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Wan B, Man Z, Li KC, Swain MV, Li Q. On elastoplastic behavior of porous enamel - an indentation and numerical study. Acta Biomater 2024:S1742-7061(24)00277-0. [PMID: 38801871 DOI: 10.1016/j.actbio.2024.05.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Revised: 05/16/2024] [Accepted: 05/22/2024] [Indexed: 05/29/2024]
Abstract
The micro/nano pores in natural mineralized tissues can, to a certain extent, affect their responses to mechanical loading but are generally ignored in existing indentation analysis. In this study, we first examined the void volume fraction of sound and caries lesion enamels through micro-computed tomography (micro-CT). A Berkovich indentation study was then carried out to characterize the effect of porous microstructure on the mechanical behavior of the human enamels. The indentation tests were also modeled using the nonlinear finite element analysis technique to simulate indentation load-displacement curves, which showed reasonable agreement with the experimental measurements. From the simulation results, the extent of densification in the plastic zone was identified and the corresponding stress and contact pressure evolutions were quantified. Further, a conventional elastic-perfectly plastic material model without considering micropores was also developed to investigate the compaction effect of the porous structure. The simulation results reveal that conventional elastic perfect-plastic constitutive models become less reliable to model the mechanical behavior of carious lesion enamel with increasing loss of mineral content as it underestimates the yield stress and plastic energy dissipation. This study divulges the importance of compaction of porous enamel structure beneath the indented area. Note that understanding the effect of porous microstructures on plastic behavior is vital as the involved inelastic deformation mechanism associated with irreversible processes such as localized microcracking has a significant bearing on wear and fatigue behavior of enamel. STATEMENT OF SIGNIFICANCE: Based on micro-CT and nano-indentation characterization, a numerical model was developed aiming to precisely describe the deformation behavior of naturally porous enamel. Inelastic properties and energy dissipation characteristics of porous enamel were investigated in detail. This work demonstrated that the existence of micro-pores in White Spot Lesions (WSLs) contributes to mechanical stability, which can mitigate the reduction in Young's modulus and fracture toughness resulting from loss of mineral components. The knowledge gained from this study can be used to explain the mechanisms related to irreversible processes, such as contact induced cracking and wear, and strengthen understanding of the mechanical behavior of porous mineralized tissues.
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Affiliation(s)
- Boyang Wan
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, NSW 2006, Australia.
| | - Ziyan Man
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, NSW 2006, Australia.
| | - Kai Chun Li
- Sir John Walsh Research Institute, University of Otago, Dunedin, New Zealand.
| | - Michael V Swain
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, NSW 2006, Australia.
| | - Qing Li
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, NSW 2006, Australia.
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Aziz S, Loch C, Li KC, Anthonappa R, Meldrum A, Ekambaram M. Remineralization potential of dentifrices with calcium sodium phosphosilicate and functionalized tri-calcium phosphate in the deeper incipient carious lesions: An in vitro study. Clin Exp Dent Res 2024; 10:e876. [PMID: 38506322 PMCID: PMC10952118 DOI: 10.1002/cre2.876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 02/04/2024] [Accepted: 02/25/2024] [Indexed: 03/21/2024] Open
Abstract
OBJECTIVES This study evaluated the remineralization potential of calcium sodium phosphosilicate and functionalized tri-calcium phosphate (f-TCP) dentifrices in deeper incipient carious lesions (ICLs). MATERIALS AND METHODS Artificial ICLs were created by placing premolars into demineralizing solutions. Teeth were randomly assigned into four groups: calcium sodium phosphosilicate (Group 1), f-TCP (Group 2), 1450 ppm fluoride (Group 3), and distilled water (Group 4), which were subjected to 10-day pH cycling. Mineral density (MD) was assessed using microcomputed tomography (Micro-CT), while hardness (H) and elastic modulus (EM) were assessed using nanomechanical testing. RESULTS MD % gain was higher in Groups 1-3 than in Group 4. In addition, Groups 1 and 2 exhibited significantly higher MD % gain than Group 3. Also, Groups 1-3 showed significantly higher EM and H values than Group 4 in the outer enamel area; yet, Groups 1 and 2 displayed significantly higher EM and H values than Groups 3 and 4 in the inner enamel. CONCLUSIONS The MD, EM, and H of ICLs significantly increased with the addition of calcium sodium phosphosilicate or f-TCP to fluoridated dentifrices compared to standard fluoride dentifrices. The added active ingredients remineralized the deeper parts of the ICLs, while remineralization at the lesion surface was similar between tested dentifrices.
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Affiliation(s)
- Shafiq Aziz
- Sir John Walsh Research Institute, Faculty of DentistryUniversity of OtagoDunedinNew Zealand
| | - Carolina Loch
- Sir John Walsh Research Institute, Faculty of DentistryUniversity of OtagoDunedinNew Zealand
| | - Kai Chun Li
- Sir John Walsh Research Institute, Faculty of DentistryUniversity of OtagoDunedinNew Zealand
| | - Robert Anthonappa
- Paediatric Dentistry, UWA Dental SchoolThe University of Western AustraliaPerthAustralia
| | - Alison Meldrum
- Sir John Walsh Research Institute, Faculty of DentistryUniversity of OtagoDunedinNew Zealand
| | - Manikandan Ekambaram
- Sir John Walsh Research Institute, Faculty of DentistryUniversity of OtagoDunedinNew Zealand
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Almejrad L, Almansour A, Bartlett D, Austin R. CAD/CAM leucite-reinforced glass-ceramic for simulation of attrition in human enamel in vitro. Dent Mater 2024; 40:173-178. [PMID: 37951749 DOI: 10.1016/j.dental.2023.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 10/25/2023] [Accepted: 11/04/2023] [Indexed: 11/14/2023]
Abstract
OBJECTIVE Investigate attrition simulation using CAD/CAM leucite-reinforced glass-ceramic antagonists on occlusal vs. buccal enamel. METHODS Three dental materials with known wear rates (resin-modified glass-ionomer, micro-filled, and fine particle composites) validated the wear simulator (CAD/CAM glass-ceramic antagonists, 200 cycles, 80 N load, deionised water irrigation, 0.7 mm sliding movement). Following this, human molars were sectioned into paired occlusal and buccal polished samples (n = 8/gp). Exposed 1.5 mm Ø enamel areas were subjected to attritional wear with and without pre-immersion in citric acid (5 min, 0.3%, pH 3.8). Profilometry measured step-height enamel wear and surface microhardness at different depths was calculated using Vickers indentation at 0.1 N and 0.5 N loads. RESULTS Dental material wear using the CAD/CAM antagonists showed consistency with previous data: mean (SD) resin-modified glass ionomer material loss of 177.77 (16.89) µm vs. 22.15 (1.30) µm fine particle hybrid composite resin wear vs. 13.63 (1.02) µm micro filled composite resin wear (P < 0.001). The coefficient of variation was less than 10%. Following validation, enamel sample wear was significantly increased when attrition was introduced (P < 0.001) independent of buccal vs. occlusal sample location (P < 0.05). Attrition resulted in occlusal wear of 26.1 ± 4.5 µm vs. buccal 26.3 ± 1.2 µm and attrition/erosion resulted in occlusal wear of 26.05 ± 4.46 µm vs. buccal 25.27 ± 1.16 µm. Whereas erosion-alone resulted in occlusal wear of 1.65 ± 0.13 µm and buccal 1.75 ± 0.03 µm. Microhardness testing at different loads revealed significantly greater hardness reductions in occlusal enamel vs. buccal enamel for 0.1 KgF indentations (P < 0.001) whereas in contrast 0.5 KgF indentations showed no differences. SIGNIFICANCE Wear simulation with CAD/CAM glass ceramic antagonists produced consistent wear in dental materials and human enamel, regardless of enamel surface origin. Lighter (0.1 KgF) hardness testing of occlusal vs. buccal origin revealed damage to the mechanical integrity of the superficial worn enamel.
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Affiliation(s)
- Lamya Almejrad
- Department of Prosthodontics, Centre for Oral, Clinical & Translational Sciences, King's College London, Faculty of Dentistry, Oral and Craniofacial Sciences, Guy's Hospital, London SE1 9RT, UK; King Saud University, Collage of Dentistry, Prosthetic Dental Science Department, Riyadh, Saudi Arabia
| | - Abdullah Almansour
- Department of Prosthodontics, Centre for Oral, Clinical & Translational Sciences, King's College London, Faculty of Dentistry, Oral and Craniofacial Sciences, Guy's Hospital, London SE1 9RT, UK; King Sattam Bin Abdulaziz University, College of Dentistry, Al-Kharj, Saudi Arabia
| | - David Bartlett
- Department of Prosthodontics, Centre for Oral, Clinical & Translational Sciences, King's College London, Faculty of Dentistry, Oral and Craniofacial Sciences, Guy's Hospital, London SE1 9RT, UK
| | - Rupert Austin
- Department of Prosthodontics, Centre for Oral, Clinical & Translational Sciences, King's College London, Faculty of Dentistry, Oral and Craniofacial Sciences, Guy's Hospital, London SE1 9RT, UK.
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Beckett DM, Vaz Viegas S, Broadbent JM, Wheeler BJ, Bērziņš K, Fraser-Miller SJ, Gordon KC, Drummond BK, Mahoney EK, Loch C. An Exploration of Mineral Density, Elemental and Chemical Composition of Primary Teeth in Relation to Cord-Blood Vitamin D, Using Laboratory Analysis Techniques. J Bone Miner Res 2023; 38:1846-1855. [PMID: 37877440 DOI: 10.1002/jbmr.4928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 09/22/2023] [Accepted: 10/06/2023] [Indexed: 10/26/2023]
Abstract
Postnatally, severe vitamin D deficiency commonly results in rickets as well as potential defects in tooth mineralization. The effects of milder deficiency on oral health outcomes later in life are still unclear. This study used micro-computed tomography (μCT), energy dispersive X-ray analysis (EDX), and Raman spectroscopy to investigate mineral density, total density, and elemental composition of enamel and dentine in 63 exfoliated primary incisors from participants with known 25-hydroxyvitamin D levels (25-OHD) at birth. No differences in mineralization and chemical composition using μCT and EDX analysis were observed irrespective of 25-OHD status. Subtle structural differences were observed via Raman spectroscopy, with more crystalline enamel observed in those with sufficient 25-OHD at birth. Although subtle, the differences seen suggest further attention should be given to children with known milder levels of vitamin D deficiency in early life. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Deanna M Beckett
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | - Shaun Vaz Viegas
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | - Jonathan M Broadbent
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | - Benjamin J Wheeler
- Paediatric Endocrinology, Te Whatu Ora Southern, Dunedin, New Zealand
- Department of Women's and Children's Health, University of Otago, Dunedin, New Zealand
| | - Kārlis Bērziņš
- Department of Pharmacy, University of Copenhagen, Copenhagen, Denmark
- Department of Chemistry, University of Otago, Dunedin, New Zealand
| | | | - Keith C Gordon
- Department of Chemistry, University of Otago, Dunedin, New Zealand
| | | | - Erin K Mahoney
- Dental Department, Te Whatu Ora Capital, Coast and Hutt Valley, Wellington, New Zealand
- Department of Paediatrics and Child Health, University of Otago, Wellington, New Zealand
| | - Carolina Loch
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
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Alqareer A, Baghdady M, Alyahya A. Three-dimensional characterization of naturally developed early caries lesions using high-resolution micro-computed tomography. J Dent 2022; 126:104317. [PMID: 36195250 DOI: 10.1016/j.jdent.2022.104317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 09/26/2022] [Accepted: 09/30/2022] [Indexed: 02/05/2023] Open
Abstract
OBJECTIVES The goal of this micro-Computed-Tomography (μCT) study was to characterize the structural parameters of natural, early proximal enamel caries lesions and correlate them with two-dimensional radiographic findings. METHODS Extracted human premolar teeth with ICDAS score 2 proximal lesions were examined using visual-tactile, μCT and simulated bitewing radiographs (BTX). Sound enamel and caries-lesions' structural and mineral density (MD) parameters were analyzed which included surface layer (SL) status and thickness, depth of lesion, and MD. RESULTS Thirty-six extracted premolars with 54 proximal early enamel caries lesions were analyzed. Lesions varied notably in lesion depth and MD. SL thickness ranged between 20 and 139μm. Three teeth (5.6%) had micro-cavitations upon the μCT examination despite being "clinically" non-cavitated. Cavitation status had no significant association with μCT nor BTX radiographic depth. Depth of lesions correlated weakly but statistically significantly with mineral loss (ML) at body of lesion (r=0.301, p=0.027). SL thickness also correlated negatively with ML at SL (r=-0.501, p<0.001). CONCLUSIONS Early proximal enamel lesions with ICDAS 2 score as determined by visual-tactile examination exhibited a wide range of lesion parameters and cavitation status when examined by μCT. Visual-tactile examination may fail to detect micro-cavitations in enamel surface that are detectable by μCT. CLINICAL SIGNIFICANCE Clinicians have direct access to early proximal enamel lesions during orthodontic separation, exfoliation, extraction or restoration of adjacent teeth. This study invites the clinician to consider more decisive management options in high risk individuals (e.g. micro-invasive techniques), given the finding of vast structural variability of such lesions.
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Affiliation(s)
- Athbi Alqareer
- Department of Developmental and Preventive Sciences, Faculty of Dentistry, Kuwait University, P.O. Box 24923 Safat, 13110, Kuwait.
| | - Mariam Baghdady
- Department of Diagnostic Sciences, Faculty of Dentistry, Kuwait University, P.O. Box 24923 Safat, 13110, Kuwait
| | - Asma Alyahya
- Department of Developmental and Preventive Sciences, Faculty of Dentistry, Kuwait University, P.O. Box 24923 Safat, 13110, Kuwait
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An Assessment of Mineral Concentration of Dental Enamel Neighbouring Hypothetical Orthodontic Brackets Using X-ray Microtomography. J Dent 2022; 126:104306. [PMID: 36162638 DOI: 10.1016/j.jdent.2022.104306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Revised: 09/14/2022] [Accepted: 09/22/2022] [Indexed: 11/21/2022] Open
Abstract
OBJECTIVES Differences in the mineral concentration (MC) level of dental enamel may represent a precursor of white spot lesions adjacent to fixed orthodontic brackets. The aim of the current in vitro study was to compare the MC level central, occlusal and cervical to orthodontic attachments. METHODS AND MATERIALS A total of 16 enamel blocks were obtained from sound human premolar samples extracted for orthodontic reasons. The buccal portion of the dental enamel blocks was divided into central, occlusal, and cervical regions and then imaged and measured to calculate the level of MC using quantitative X-ray microtomography methods (XMT) at each site. RESULTS There was a substantial variation in the mineral concentration with the lowest level being detected in the cervical region when compared with other regions. The MC of the gingival zone was significantly lower than that of the middle zone (P<0.05) and was insignificantly lower than that of the occlusal zone. CONCLUSION Within the limitations of the current study, it can be concluded that the cervical region of the permanent enamel had the lowest mineral concentration using XMT. The cervical region may therefore be more vulnerable to the development of white spot lesions (WSLs) adjacent to a fixed orthodontic appliance during orthodontic treatment. CLINICAL SIGNIFICANCE Using X-ray microtomography lower mineral concentration in the cervical region of the enamel was observed. This may make these areas particularly susceptible to demineralisation during fixed appliance-based orthodontic treatment and may influence the bond strength of fixed orthodontic attachments.
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Desoutter A, Cases O, Collart Dutilleul PY, Simancas Escorcia V, Cannaya V, Cuisinier F, Kozyraki R. Enamel and dentin in Enamel renal syndrome: A confocal Raman microscopy view. Front Physiol 2022; 13:957110. [PMID: 36091358 PMCID: PMC9453029 DOI: 10.3389/fphys.2022.957110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 08/01/2022] [Indexed: 11/13/2022] Open
Abstract
Enamel Renal Syndrome (ERS) is a rare genetic disorder caused by biallelic mutations in Family with sequence similarity 20A (FAM20A) gene encoding the secretory pathway pseudokinase FAM20A. ERS is characterized by hypoplastic amelogenesis imperfecta (AI), impaired tooth eruption, intra-pulpal calcifications, gingival fibromatosis and nephrocalcinosis of various severity. Previous studies showed that the hypoplastic enamel was also hypomineralized but its chemical composition has not been extensively studied. Furthermore it is currently unclear whether dentinal defects are associated with AI in ERS patients. The objective of the study was to provide a structural and chemical analysis of enamel, dentin and dentin enamel junction (DEJ) in ERS patients carrying four, previously reported, distinct mutations in FAM20A. Chemical cartography obtained with Raman microscopy showed that compared to control samples, ERS enamel composition was severely altered and a cementum-like structure was observed in some cases. Chemical composition of peripulpal dentin was also affected and usual gradient of phosphate intensity, shown in DEJ profile, was absent in ERS samples. DEJ and dentinal anomalies were further confirmed by scanning electron microscopy analysis. In conclusion, our study shows that enamel formation is severely compromised in ERS patients and provides evidence that dentinal defects are an additional feature of the ERS dental phenotype.
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Affiliation(s)
- Alban Desoutter
- Laboratoire Bioingénierie et Nanosciences LBN, Université de Montpellier, Montpellier, France
- *Correspondence: Alban Desoutter,
| | - Olivier Cases
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris Cité, Laboratory of Oral Molecular Pathophysiology, Paris, France
| | | | - Victor Simancas Escorcia
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris Cité, Laboratory of Oral Molecular Pathophysiology, Paris, France
- Facultad de Odontología, Universidad de Cartagena, Grupo Interdisciplinario de Investigaciones y Tratamientos Odontológicos Universidad de Cartagena (GITOUC), Cartagena, Colombia
| | - Vidjea Cannaya
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris Cité, Laboratory of Oral Molecular Pathophysiology, Paris, France
| | - Frédéric Cuisinier
- Laboratoire Bioingénierie et Nanosciences LBN, Université de Montpellier, Montpellier, France
| | - Renata Kozyraki
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris Cité, Laboratory of Oral Molecular Pathophysiology, Paris, France
- CRMR O-RARES, Hôpital Rothshild, UFR d’Odontologie-Garancière, Université de Paris Cité, Paris, France
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Moheet IA, Luddin N, Ab Rahman I, Masudi SM, Kannan TP, Nik Abd Ghani NR. Analysis of Ionic-Exchange of Selected Elements between Novel Nano-Hydroxyapatite-Silica Added Glass Ionomer Cement and Natural Teeth. Polymers (Basel) 2021; 13:polym13203504. [PMID: 34685263 PMCID: PMC8537145 DOI: 10.3390/polym13203504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Revised: 10/05/2021] [Accepted: 10/08/2021] [Indexed: 11/16/2022] Open
Abstract
One of the foremost missions in restorative dentistry is to discover a suitable material that can substitute lost and damaged tooth structure. To this date, most of the restorative materials utilized in dentistry are bio-inert. It is predicted that the addition of nano-HA-SiO2 to GIC matrix could produce a material with better ion-exchange between the restorative material and natural teeth. Therefore, the aim of the current study was to synthesize and investigate the transfer of specific elements (calcium, phosphorus, fluoride, silica, strontium, and alumina) between nano-hydroxyapatite-silica added GIC (nano-HA-SiO2-GIC) and human enamel and dentine. The novel nano-hydroxyapatite-silica (nano-HA-SiO2) was synthesized using one-pot sol-gel method and added to cGIC. Semi-quantitative energy dispersive X-ray (EDX) analysis was carried out to determine the elemental distribution of fluorine, silicon, phosphorus, calcium, strontium, and aluminum. Semi-quantitative energy dispersive X-ray (EDX) analysis was performed by collecting line-scans and dot-scans. The results of the current study seem to confirm the ionic exchange between nano-HA-SiO2-GIC and natural teeth, leading to the conclusion that increased remineralization may be possible with nano-HA-SiO2-GIC as compared to cGIC (Fuji IX).
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Affiliation(s)
- Imran Alam Moheet
- Baqai Dental College, Baqai Medical University, Karachi 75340, Pakistan;
| | - Norhayati Luddin
- School of Dental Sciences, Universiti Sains Malaysia, Kubang Kerian 16150, Kelantan, Malaysia; (I.A.R.); (T.P.K.); (N.R.N.A.G.)
- Correspondence: ; Tel.: +60-199-381-138
| | - Ismail Ab Rahman
- School of Dental Sciences, Universiti Sains Malaysia, Kubang Kerian 16150, Kelantan, Malaysia; (I.A.R.); (T.P.K.); (N.R.N.A.G.)
| | - Sam’an Malik Masudi
- Faculty of Dentistry, Lincoln University College, Petaling Jaya 47301, Selangor, Malaysia;
| | - Thirumulu Ponnuraj Kannan
- School of Dental Sciences, Universiti Sains Malaysia, Kubang Kerian 16150, Kelantan, Malaysia; (I.A.R.); (T.P.K.); (N.R.N.A.G.)
| | - Nik Rozainah Nik Abd Ghani
- School of Dental Sciences, Universiti Sains Malaysia, Kubang Kerian 16150, Kelantan, Malaysia; (I.A.R.); (T.P.K.); (N.R.N.A.G.)
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Barreto de Oliveira RD, de Sousa FB, Algarni AA, Eckert GJ, Hara AT. Susceptibility of Dental Enamel of Different Ages to Caries-Like Lesion Development. Caries Res 2020; 54:475-482. [PMID: 33176329 DOI: 10.1159/000509461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 06/10/2020] [Indexed: 11/19/2022] Open
Abstract
This study investigated the impact of estimated age, anatomical location, and the presence of wear facets on the susceptibility of enamel to develop caries-like lesions. Extracted human premolars (n = 261) had their age estimated between 10 and 93 years old, using established forensic methods. Specimens of enamel (4 × 4 mm) were prepared from the middle of the buccal surfaces, preserving the outer surface layer. The central area of the block (4 × 1 mm) was protected with nail polish and used as an internal control. The specimens were demineralized for 8 days (with 0.1 M acetic acid, 1.28 mM Ca, 0.74 mM Pi, and 0.03 µg F/mL, pH 5.0), to simulate caries-like lesion development. They were then scanned individually using microtomography, and digital 2D images were used to calculate the outcomes of integrated mineral concentration loss (ΔZ in µm/g/cm3) and lesion depth (LD in µm) at 3 locations, i.e., the cervical, middle, and occlusal thirds. The presence of natural surface wear facets was considered in the analysis. Data were evaluated using a linear mixed-effects models (α = 0.05). ΔZ increased significantly as a function of estimated tooth age at all 3 locations, and this increase was greater after the age of 30 years (p < 0.001), when a higher ΔZ was found in the occlusal third than in the middle and cervical thirds (p < 0.001). LD increased only in the occlusal third before the age of 30 years (p = 0.039) and this increase was significantly greater after 30 years at all 3 locations (p < 0.01), with no differences among them (p > 0.15). The presence of wear facets significantly increased ΔZ and LD (p < 0.001 for both). Overall, we concluded that the susceptibility of enamel to developing caries-like lesions increased with estimated dental age. This effect was more pronounced after the estimated age of 30 years and in the presence of natural tooth wear facets.
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Affiliation(s)
| | | | - Amnah A Algarni
- Department of Restorative Dentistry, College of Dentistry, Taibah University, Medina, Saudi Arabia
| | - George J Eckert
- Department of Biostatistics, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Anderson T Hara
- Department of Cariology, Operative Dentistry and Dental Public Health, Indiana University School of Dentistry, Indianapolis, Indiana, USA,
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Malik QUA, Iftikhar S, Zahid S, Safi SZ, Khan AF, Nawshad M, Ghafoor S, Khan AS, Tufail Shah A. Smart injectable self-setting bioceramics for dental applications. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2020; 113:110956. [PMID: 32487378 DOI: 10.1016/j.msec.2020.110956] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 03/29/2020] [Accepted: 04/10/2020] [Indexed: 10/24/2022]
Abstract
A thermo-responsive injectable bioactive glass (BAG) that has the ability to set at body temperature was prepared using pluronic F127 and hydroxypropyl methylcellulose as the carrier. The injectable composite has the advantage to fill irregular shape implantation sites and quick setting at body temperature. The structural and morphological analysis of injectable BAG before and after setting was done by using Fourier Transform Infrared spectroscopy (FTIR), and Scanning Electron Microscope (SEM). The effect of an ultrasonic scaler for a quick setting of injectable BAG was also investigated. The ultrasonic scaler sets the BAG formulation three-folds faster than at body temperature and homogenized the dispersion. The in vitro bio-adhesion was studied in the bovine tooth in both artificial saliva and deionized water for periodic time intervals, i.e., day 7, 30, 90, and 180, which confirmed the apatite layer formation. The mineral density analysis was used to differentiate the newly formed apatite with tooth apatite. In the MTT assay, the experimental material showed continuous proliferation and cell growth. This indicated that injectable hydrogel promoted cell growth, facilitated proliferation, and had no cytotoxic effect. The SEM and micro-CT results (performed after in vitro bioactivity testing) showed that the injectable BAG had the ability to regenerate dentin, hence this material has the potential to be used for dental and biomedical applications including tooth and bone regeneration in minimally invasive procedures in future.
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Affiliation(s)
- Qurat Ul Ain Malik
- Interdisciplinary Research Centre in Biomedical Materials, COMSATS University Islamabad, Lahore Campus, 54000, Pakistan; Department of Oral Biology, University of Health Sciences Lahore, Khayaban-e-Jamia Punjab, Lahore, 54600, Pakistan
| | - Sundus Iftikhar
- Interdisciplinary Research Centre in Biomedical Materials, COMSATS University Islamabad, Lahore Campus, 54000, Pakistan; Department of Oral Biology, University of Health Sciences Lahore, Khayaban-e-Jamia Punjab, Lahore, 54600, Pakistan
| | - Saba Zahid
- Interdisciplinary Research Centre in Biomedical Materials, COMSATS University Islamabad, Lahore Campus, 54000, Pakistan
| | - Sher Zaman Safi
- Interdisciplinary Research Centre in Biomedical Materials, COMSATS University Islamabad, Lahore Campus, 54000, Pakistan
| | - Ather Farooq Khan
- Interdisciplinary Research Centre in Biomedical Materials, COMSATS University Islamabad, Lahore Campus, 54000, Pakistan
| | - Muhammad Nawshad
- Interdisciplinary Research Centre in Biomedical Materials, COMSATS University Islamabad, Lahore Campus, 54000, Pakistan
| | - Sarah Ghafoor
- Department of Oral Biology, University of Health Sciences Lahore, Khayaban-e-Jamia Punjab, Lahore, 54600, Pakistan
| | - Abdul Samad Khan
- Department of Restorative Dental Sciences, College of Dentistry, Imam Abdulrahman Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia.
| | - Asma Tufail Shah
- Interdisciplinary Research Centre in Biomedical Materials, COMSATS University Islamabad, Lahore Campus, 54000, Pakistan.
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Alyahya A, Alqareer A, Swain M. Microcomputed Tomography Calibration Using Polymers and Minerals for Enamel Mineral Content Quantitation. Med Princ Pract 2019; 28:247-255. [PMID: 30820021 PMCID: PMC6597939 DOI: 10.1159/000499186] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Accepted: 02/28/2019] [Indexed: 12/15/2022] Open
Abstract
OBJECTIVE The aim of this paper was to develop calibration standards (CSs) that are readily available for clinical researchers for the quantitation of enamel mineral content. METHOD Polyethylene terephthalate (PET), acetal, polyphenylene sulfide (PPS), selenite, Egyptian alabaster, aragonite, and fluorite were fashioned into discs, and their densities were measured and stacked for microcomputed tomography examination. Frame averaging, flat-field correction, pre-filtration, and beam-hardening correction were applied. CSs were checked for homogeneity. The linear relationship between the mean greyscale value (GSV) of each disc and its physically calculated density was explored, and reproducibility was tested. A calibration function was established and then validated using a bovine enamel disc and sound enamel of extracted human premolar teeth. RESULTS Measured densities were PET (ρ = 1.38 g/cm3), acetal (ρ = 1.41 g/cm3), PPS (ρ = 1.64 g/cm3), selenite (ρ = 2.24 g/cm3), Egyptian alabaster (ρ = 2.7 g/cm3), aragonite (ρ = 2.72 g/cm3), and fluorite (ρ = 3.11 g/cm3). Examination of the profile sections of CSs confirmed the uniformity of GSVs with minimal beam-hardening effect. A squared Pearson correlation coefficient of R2 = 0.994 was determined between the mean GSV of each CS and its calculated density and was reproduced at different settings with R2 >0.99. A linear regression equation of density (y) versus GSV (x) was established using the least squares regression equation method. The estimated density of the bovine enamel disc (2.48 g/cm3) showed high accuracy when compared to the physically measured value (2.45 g/cm3). The -relative error was 1.2%. Densities of sound enamel in the extracted human premolar teeth were 2.6-3.1 g/cm3. CONCLUSIONS This is a simple, valid, and reproducible method to quantitate enamel mineral content. This simple, yet accurate system could be used to expand knowledge in the field of enamel caries research.
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Affiliation(s)
- Asma Alyahya
- Department of Developmental and Preventive Sciences, Faculty of Dentistry, Kuwait University, Safat, Kuwait,
| | - Athbi Alqareer
- Department of Developmental and Preventive Sciences, Faculty of Dentistry, Kuwait University, Safat, Kuwait
| | - Michael Swain
- Department of Bioclinical Sciences, Faculty of Dentistry, Kuwait University, Safat, Kuwait
- Don State Technical University, Rostov-on-Don, Russian Federation
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Al-Mosawi M, Davis GR, Bushby A, Montgomery J, Beaumont J, Al-Jawad M. Crystallographic texture and mineral concentration quantification of developing and mature human incisal enamel. Sci Rep 2018; 8:14449. [PMID: 30262903 PMCID: PMC6160435 DOI: 10.1038/s41598-018-32425-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 08/30/2018] [Indexed: 11/08/2022] Open
Abstract
For human dental enamel, what is the precise mineralization progression spatially and the precise timing of mineralization? This is an important question in the fundamental understanding of matrix-mediated biomineralization events, but in particular because we can use our understanding of this natural tissue growth in humans to develop biomimetic approaches to repair and replace lost enamel tissue. It is important to understand human tissues in particular since different species have quite distinct spatial and temporal progression of mineralization. In this study, five human central incisors at different stages of enamel maturation/mineralization were spatially mapped using synchrotron X-ray diffraction and X-ray microtomography techniques. From the earliest developmental stage, two crystallite-orientation populations coexist with angular separations between the crystallite populations of approximately 40° varying as a function of position within the tooth crown. In general, one population had significantly lower texture magnitude and contributed a higher percentage to the overall crystalline structure, compared to the other population which contributed only 20-30% but had significantly higher texture magnitude. This quantitative analysis allows us to understand the complex and co-operative structure-function relationship between two populations of crystallites within human enamel. There was an increase in the mineral concentration from the enamel-dentin junction peripherally and from the incisal tip cervically as a function of maturation time. Quantitative backscattered-electron analyses showed that mineralization of prism cores precedes that of prism boundaries. These results provide new insights into the precise understanding of the natural growth of human enamel.
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Affiliation(s)
- Mohammed Al-Mosawi
- Institute of Dentistry, Barts and the London School of Medicine and Dentistry, Queen Mary, University of London, London, E1 4NS, United Kingdom
| | - Graham Roy Davis
- Institute of Dentistry, Barts and the London School of Medicine and Dentistry, Queen Mary, University of London, London, E1 4NS, United Kingdom
| | - Andy Bushby
- School of Engineering and Materials Science, Queen Mary University of London, London, E1 4NS, United Kingdom
| | - Janet Montgomery
- Department of Archaeology, Durham University, South Road, Durham, DH1 3LE, United Kingdom
| | - Julia Beaumont
- School of Archaeological and Forensic Sciences, University of Bradford, Bradford, BD7 1DP, United Kingdom
| | - Maisoon Al-Jawad
- Institute of Dentistry, Barts and the London School of Medicine and Dentistry, Queen Mary, University of London, London, E1 4NS, United Kingdom.
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Woods C, Fernee C, Browne M, Zakrzewski S, Dickinson A. The potential of statistical shape modelling for geometric morphometric analysis of human teeth in archaeological research. PLoS One 2017; 12:e0186754. [PMID: 29216199 PMCID: PMC5720725 DOI: 10.1371/journal.pone.0186754] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2017] [Accepted: 10/07/2017] [Indexed: 01/15/2023] Open
Abstract
This paper introduces statistical shape modelling (SSM) for use in osteoarchaeology research. SSM is a full field, multi-material analytical technique, and is presented as a supplementary geometric morphometric (GM) tool. Lower mandibular canines from two archaeological populations and one modern population were sampled, digitised using micro-CT, aligned, registered to a baseline and statistically modelled using principal component analysis (PCA). Sample material properties were incorporated as a binary enamel/dentin parameter. Results were assessed qualitatively and quantitatively using anatomical landmarks. Finally, the technique’s application was demonstrated for inter-sample comparison through analysis of the principal component (PC) weights. It was found that SSM could provide high detail qualitative and quantitative insight with respect to archaeological inter- and intra-sample variability. This technique has value for archaeological, biomechanical and forensic applications including identification, finite element analysis (FEA) and reconstruction from partial datasets.
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Affiliation(s)
- Christopher Woods
- Bioengineering Sciences Research Group, University of Southampton, Highfield Campus, Highfield, Southampton, United Kingdom
| | - Christianne Fernee
- Department of Archaeology, University of Southampton, Avenue Campus, Highfield, Southampton, United Kingdom
| | - Martin Browne
- Bioengineering Sciences Research Group, University of Southampton, Highfield Campus, Highfield, Southampton, United Kingdom
| | - Sonia Zakrzewski
- Department of Archaeology, University of Southampton, Avenue Campus, Highfield, Southampton, United Kingdom
| | - Alexander Dickinson
- Bioengineering Sciences Research Group, University of Southampton, Highfield Campus, Highfield, Southampton, United Kingdom
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Gomes MN, Rodrigues FP, Silikas N, Francci CE. Micro-CT and FE-SEM enamel analyses of calcium-based agent application after bleaching. Clin Oral Investig 2017; 22:961-970. [PMID: 28689366 DOI: 10.1007/s00784-017-2175-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 06/28/2017] [Indexed: 10/19/2022]
Abstract
OBJECTIVES The objective of the present study is to evaluate the effects of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on bleached enamel. MATERIALS AND METHODS A bleaching agent (35% hydrogen peroxide) was applied, 4 × 8 min on premolar teeth (n = 8). A CPP-ACP paste was applied for 7 days. Prior and post-treatment, microtomography images were obtained and 3D regions of interest (ROIs) were selected, from outer enamel, extending to 110.2-μm depth. CT parameters of structure: thickness (St.Th), separation (St.Sp), and fragmentation index (Fr.I.) were calculated for each (ROI). Data was submitted to paired t tests at a 95% confidence level. The samples were evaluated at 3000 to 100,000 magnification. Quantitative analysis of enamel mineral content was also determined by SEM EDX. RESULTS There was a significant increase in structure thickness and calcium content. The phosphorus content increased after bleaching. There was also a decreased separation and fragmentation index on the outer enamel to a depth of 56.2 μm (p < 0.05). There were no changes at 110.2-μm depth for the bleaching CPP-ACP association. A covering layer and decreased spaces between the hydroxyapatite crystals appeared around the enamel prisms, 7 days after the CPP-ACP application. CONCLUSIONS The application of a CPP-ACP provides a compact structure on the enamel's outer surface, for 7 days, due to calcium deposition. CT parameters seem to be a useful tool for mineralizing and remineralizing future studies. CLINICAL RELEVANCE CPP-ACP neutralizes any adverse effects on enamel surface when applied during a week after bleaching and minimizes any side effects of the bleaching treatment due to a more compact structure.
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Affiliation(s)
- Mauricio Neves Gomes
- Department of Biomaterials and Oral Biology, School of Dentistry, University of São Paulo, Av. Prof. Lineu Prestes, 2227, Cidade Universitária, São Paulo, SP, 05508-900, Brazil.
| | - Flávia Pires Rodrigues
- Post-graduate Programme in Dentistry, School of Dentistry, Paulista University-UNIP, Av. Dr Bacelar 1212, Vila Clementino, São Paulo, SP, 04026-002, Brazil.,Department of Restorative Dentistry School of Dentistry Faculty of Pharmacy, Dentistry and Nursing, Federal University of Ceará, R. Gilberto Studart, 770/901, Cocó, Fortaleza, CE, 60190-750, Brazil
| | - Nick Silikas
- Biomaterials Science Research Group, School of Dentistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Carlos Eduardo Francci
- Department of Biomaterials and Oral Biology, School of Dentistry, University of São Paulo, Av. Prof. Lineu Prestes, 2227, Cidade Universitária, São Paulo, SP, 05508-900, Brazil
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Akkus A, Karasik D, Roperto R. Correlation between micro-hardness and mineral content in healthy human enamel. J Clin Exp Dent 2017; 9:e569-e573. [PMID: 28469825 PMCID: PMC5410680 DOI: 10.4317/jced.53345] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 07/18/2016] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND Enamel is the hardest and the stiffest tissue in the human body. The enamel undergoes multidirectional stresses, withstands multimillion chewing cycles, all while protecting the internal dentin and pulp from damage due to mechanical overload and exposure to the harsh chemical environment of the mouth. Raman spectroscopy allows to study enamel mineral content in a non-destructive and site-specific way. While Raman spectroscopy has been applied in other studies to assess tooth mineralization, there are no studies that examine the relationship between micro-hardness and mineral content of the untreated enamel. An understanding of this relationship is extremely important in a clinical context. The effect of various agents on enamel hardness was investigated, though the relationship between healthy enamel mineral content and micro-hardness remains obscure. MATERIAL AND METHODS Twenty human incisor teeth were obtained in compliance with the NIH guidelines and imaged site-specifically with a Raman microscope and evaluated with a Brinell hardness measurement device. The front portion of each tooth was divided into apical, medium and cervical regions and subsequently imaged with a Raman microscope in these three locations. RESULTS AND CONCLUSIONS The results demonstrated that enamel mineral content varies significantly between individuals and is correlated with the hardness of the enamel. Non-invasive, sample preparation free Raman spectroscopy was successfully employed to measure the mineral content of healthy enamel and it correlated the mineralization score to the hardness measurements of the selected cervical location. The overall level of enamel mineral content may serve as a robust predictor of patients' susceptibility to developing caries, and overall enamels wear resistance, thus allowing for the prevention of caries via clinically available methods of remineralization, fluoride treatment and frequent cleaning. Key words:Enamel, raman spectroscopy, micro-hardness, extracted teeth.
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Affiliation(s)
- Anna Akkus
- Department of Comprehensive Care, Case Western Reserve University, Cleveland, Ohio 44106, USA
| | | | - Renato Roperto
- Department of Comprehensive Care, Case Western Reserve University, Cleveland, Ohio 44106, USA
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Kucuk EB, Malkoc S, Demir A. Microcomputed tomography evaluation of white spot lesion remineralization with various procedures. Am J Orthod Dentofacial Orthop 2017; 150:483-90. [PMID: 27585777 DOI: 10.1016/j.ajodo.2016.02.026] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 02/01/2016] [Accepted: 02/01/2016] [Indexed: 11/29/2022]
Abstract
INTRODUCTION The aim of this study was to use microcomputed tomography to evaluate the effects on white spot lesions of 3 remineralizing agents compared with artificial saliva (Inonu University, Malatya, Turkey). The agents were GC Tooth Mousse (GC International, Itabashi-ku, Tokyo, Japan), 50-ppm sodium fluoride solution (Inonu University, Malatya, Turkey), and Clinpro 5000 (3M ESPE Dental Products (St Paul, Minn). The experimental and control teeth were stored in artificial saliva. METHODS Forty-four extracted premolars were divided into 4 groups of 11 teeth each (3 experimental groups and 1 control group). After white spot lesions were created on the teeth, a remineralizing agent was applied. Microcomputed tomography scanning was performed at the following times: T0 (sound enamel), T1 (day 0, when the white spot lesion was formed), T2 (day 15), and T3 (day 30). Volume, depth, surface area, and mineral density changes of the white spot lesions were evaluated at different time points using CTAn software (SkyScan; Bruker, Kontich, Belgium). RESULTS GC Tooth Mousse and Clinpro 5000 improved all measurements after 30 days. However, Clinpro 5000 was not as effective in reducing lesion depth as it was in the other parameters. The artificial saliva group and the 50-ppm sodium fluoride solution did not show significant effects in the regression of the white spot lesions at the end of the 30-day experiment. CONCLUSIONS GC Tooth Mousse and Clinpro 5000 were more effective in remineralization of white spot lesions than sodium fluoride solution and artificial saliva. They can be preferred for use clinically. Microcomputed tomography is a novel and effective method that shows promise in accurately evaluating white spot lesions and remineralization.
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Affiliation(s)
- Eyup Burak Kucuk
- Assistant professor, Department of Orthodontics, Faculty of Dentistry, Mustafa Kemal University, Hatay, Turkey.
| | - Siddik Malkoc
- Professor, Department of Orthodontics, Faculty of Dentistry, İnönü University, Malatya, Turkey
| | - Abdullah Demir
- Professor, Department of Orthodontics, Faculty of Dentistry, Selçuk University, Konya, Turkey
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Gambetta-Tessini K, Mariño R, Ghanim A, Adams GG, Manton DJ. Validation of quantitative light-induced fluorescence-digital in the quantification of demarcated hypomineralized lesions of enamel. ACTA ACUST UNITED AC 2017; 8. [DOI: 10.1111/jicd.12259] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 11/17/2016] [Indexed: 11/28/2022]
Affiliation(s)
- Karla Gambetta-Tessini
- Oral Health Cooperative Research Centre; Melbourne Dental School; The University of Melbourne; Melbourne Victoria Australia
| | - Rodrigo Mariño
- Oral Health Cooperative Research Centre; Melbourne Dental School; The University of Melbourne; Melbourne Victoria Australia
| | - Aghareed Ghanim
- Oral Health Cooperative Research Centre; Melbourne Dental School; The University of Melbourne; Melbourne Victoria Australia
| | - Geoffrey G. Adams
- Oral Health Cooperative Research Centre; Melbourne Dental School; The University of Melbourne; Melbourne Victoria Australia
| | - David J. Manton
- Oral Health Cooperative Research Centre; Melbourne Dental School; The University of Melbourne; Melbourne Victoria Australia
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18
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Akkus A, Yang S, Roperto R, Mustafa H, Teich S, Akkus O. A portable fiber-optic raman spectrometer concept for evaluation of mineral content within enamel tissue. J Clin Exp Dent 2017; 9:e238-e241. [PMID: 28210442 PMCID: PMC5303324 DOI: 10.4317/jced.53185] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 06/08/2016] [Indexed: 11/24/2022] Open
Abstract
Background Measurement of tooth enamel mineralization using a clinically viable method is essential since variation of mineralization may be used to monitor caries risk or in assessing the effectiveness of remineralization therapy. Fiber optic Raman systems are becoming more affordable and popular in context of biomedical applications. However, the applicability of fiber optic Raman systems for measurement of mineral content within enamel tissue has not been elucidated significantly in the prior literature. Material and Methods Human teeth with varying degrees of enamel mineralization were selected. In addition alligator, boar and buffalo teeth which have increasing amount of mineral content, respectively, were also included as another set of samples. Reference Raman measurements of mineralization were performed using a high-fidelity confocal Raman microscope. Results Analysis of human teeth by research grade Raman system indicated a 2-fold difference in the Raman intensities of v1 symmetric-stretch bands of mineral-related phosphate bonds and 7-fold increase in mineral related Raman intensities of animal teeth. However, fiber optic system failed to resolve the differences in the mineralization of human teeth. Conclusions These results indicate that the sampling volume of fiber optic systems extends to the underlying dentin and that confocal aperture modification is essential to limit the sampling volume to within the enamel. Further research efforts will focus on putting together portable Raman systems integrated with confocal fiber probe. Key words:Enamel, mineral content, raman spectroscopy.
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Affiliation(s)
- Anna Akkus
- PhD, CWRU School of Dental Medicine, 2124 Cornell Road, Cleveland, OH 44106-4905
| | - Shan Yang
- PhD, Jackson State University, Department of Physics, Atmospheric Science and Geophysics, 1400 John R. Lynch St Jackson, MS 39217
| | - Renato Roperto
- DDS, MSc, PhD, CWRU School of Dental Medicine, 2124 Cornell Road, Cleveland, OH 44106-4905
| | - Hathem Mustafa
- PhD, Department of Mechanical and Aerospace Engineering, Case Western Reserve University, 10900 Euclid Ave.Cleveland, Ohio 44106-7222
| | - Sorin Teich
- DDS, MBA, CWRU School of Dental Medicine, 2124 Cornell Road, Cleveland, OH 44106-4905
| | - Ozan Akkus
- PhD, Department of Mechanical and Aerospace Engineering, Case Western Reserve University, 10900 Euclid Ave.Cleveland, Ohio 44106-7222
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Akkus A, Akkus A, Roperto R, Akkus O, Porto T, Teich S, Lang L. Evaluation of mineral content in healthy permanent human enamel by Raman spectroscopy. J Clin Exp Dent 2016; 8:e546-e549. [PMID: 27957268 PMCID: PMC5149089 DOI: 10.4317/jced.53057] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 03/16/2016] [Indexed: 11/30/2022] Open
Abstract
Background An understanding of tooth enamel mineral content using a clinically viable method is essential since variations in mineralization may serve as an early precursor of a dental health issues, and may predict progression and architecture of decay in addition to assessing the success and effectiveness of the remineralization strategies. Material and Methods Twenty two human incisor teeth were obtained in compliance with the NIH guidelines and site specifically imaged with Raman microscope. The front portion of the teeth was divided into apical, medium and cervical regions and subsequently imaged with Raman microscope in these three locations. Results Measured mineralization levels have varied substantially depending on the regions. It was also observed that, the cervical enamel is the least mineralization as a populational average. Conclusions Enamel mineralization is affected by a many factors such as are poor oral hygiene, alcohol consumption and high intake of dietary carbohydrates, however the net effect manifests as overall mineral content of the enamel. Thus an early identification of the individual with overall low mineral content of the enamel may be a valuable screening tool in determining a group with much higher than average caries risk, allowing intervention before development of caries. Clinically applicable non-invasive techniques that can quantify mineral content, such as Raman analysis, would help answer whether or not mineralization is associated with caries risk. Key words:Enamel, Raman spectroscopy, mineral content, dental caries.
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Affiliation(s)
- Anna Akkus
- PhD, Department of Comprehensive Care, School of Dental Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Asya Akkus
- Case Biomanufacturing and Microfabrication Laboratory, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Renato Roperto
- DDS, MSc, PhD, Department of Comprehensive Care, School of Dental Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Ozan Akkus
- PhD, Department of Mechanical and Aerospace Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Thiago Porto
- PhD, Department of Comprehensive Care, School of Dental Medicine, Case Western Reserve University, Cleveland, OH 44106, USA; DDS, MSc, PhD, Department of Restorative Dentistry, Faculty of Dentistry, Sao Paulo State University, Araraquara, SP, Brazil
| | - Sorin Teich
- DDS, MBA, Department of Comprehensive Care, School of Dental Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Lisa Lang
- DDS, MBA, Department of Comprehensive Care, School of Dental Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
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Smith CEL, Murillo G, Brookes SJ, Poulter JA, Silva S, Kirkham J, Inglehearn CF, Mighell AJ. Deletion of amelotin exons 3-6 is associated with amelogenesis imperfecta. Hum Mol Genet 2016; 25:3578-3587. [PMID: 27412008 PMCID: PMC5179951 DOI: 10.1093/hmg/ddw203] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 06/17/2016] [Accepted: 06/21/2016] [Indexed: 11/15/2022] Open
Abstract
Amelogenesis imperfecta (AI) is a heterogeneous group of genetic conditions that result in defective dental enamel formation. Amelotin (AMTN) is a secreted protein thought to act as a promoter of matrix mineralization in the final stage of enamel development, and is strongly expressed, almost exclusively, in maturation stage ameloblasts. Amtn overexpression and Amtn knockout mouse models have defective enamel with no other associated phenotypes, highlighting AMTN as an excellent candidate gene for human AI. However, no AMTN mutations have yet been associated with human AI. Using whole exome sequencing, we identified an 8,678 bp heterozygous genomic deletion encompassing exons 3-6 of AMTN in a Costa Rican family segregating dominant hypomineralised AI. The deletion corresponds to an in-frame deletion of 92 amino acids, shortening the protein from 209 to 117 residues. Exfoliated primary teeth from an affected family member had enamel that was of a lower mineral density compared to control enamel and exhibited structural defects at least some of which appeared to be associated with organic material as evidenced using elemental analysis. This study demonstrates for the first time that AMTN mutations cause non-syndromic human AI and explores the human phenotype, comparing it with that of mice with disrupted Amtn function.
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Affiliation(s)
- Claire E L Smith
- Leeds Institute of Biomedical and Clinical Sciences, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK.,Department of Oral Biology, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK
| | - Gina Murillo
- University of Costa Rica, School of Dentistry, San Pedro, Costa Rica
| | - Steven J Brookes
- Department of Oral Biology, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK
| | - James A Poulter
- Leeds Institute of Biomedical and Clinical Sciences, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK
| | - Sandra Silva
- University of Costa Rica, Molecular Biology Cellular Centre (CBCM), San Pedro, Costa Rica and
| | - Jennifer Kirkham
- Department of Oral Biology, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK
| | - Chris F Inglehearn
- Leeds Institute of Biomedical and Clinical Sciences, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK
| | - Alan J Mighell
- Leeds Institute of Biomedical and Clinical Sciences, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK, .,School of Dentistry, University of Leeds, Leeds LS2 9LU, UK
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Shahmoradi M, Swain MV. Quantitative characterization and micro-CT mineral mapping of natural fissural enamel lesions. J Dent 2016; 46:23-9. [PMID: 26836704 DOI: 10.1016/j.jdent.2016.01.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 01/21/2016] [Accepted: 01/27/2016] [Indexed: 10/22/2022] Open
Abstract
OBJECTIVES The aim of this study was to characterize the mineral distribution pattern of natural fissural enamel lesions and to quantify structural parameters and mineral density of these lesions in comparison to proximal white spot enamel lesions. METHODS Imaging was undertaken using a high-resolution desktop micro-computed tomography system. A calibration equation was used to transform the grey level values of images into true mineral density values. The value of lesion parameters including the mineral density and the thickness of the surface layer of the enamel lesion were extracted from mineral density profiles. RESULTS The thickness of the surface layer showed variation among different lesions and it ranged from 0-90 μm in proximal lesions and 0-137 μm in fissural lesions. The average thickness of surface layer in fissural lesions was significantly higher than smooth surface proximal lesions. Sound fissural enamel showed lower mineral density compared to proximal enamel. CONCLUSION Micro-CT and the suggested de-noising and visualization method provide an efficient high-resolution approach for non-destructive evaluation of fissural lesions. Using these methods, the current study revealed the exclusive pattern and structure of fissural enamel lesions which may provide a basis for future studies on prevention and remineralization of these lesions. CLINICAL SIGNIFICANCE The common demineralization pattern of fissural lesions, which indicates the extension of the lesion in two directions towards the pulp horns, may explain the early inflammation and symptoms of the pulp in fissural lesions even when the lesion base appears far from the pulp roof in normal radiographs. In addition, the presence of the surface layer, indicates that vigorous probing of the occlusal fissures may lead to breakage and cavitation of the enamel lesions.
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Affiliation(s)
- Mahdi Shahmoradi
- Biomaterials and Bioengineering, Faculty of Dentistry, The University of Sydney, Australia
| | - Michael V Swain
- Biomaterials and Bioengineering, Faculty of Dentistry, The University of Sydney, Australia; Faculty of Dentistry, Health Sciences Centre, Kuwait University, Kuwait.
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22
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Das B, Muthu MS, Farzan JM. Comparison of the chemical composition of normal enamel from exfoliated primary teeth and teeth affected with early childhood caries: an in vitro study. Int J Paediatr Dent 2016; 26:20-5. [PMID: 25604081 DOI: 10.1111/ipd.12153] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
AIM The aim of this study was to compare the chemical composition of enamel from teeth with early childhood caries (unaffected fragments) and from healthy primary teeth. DESIGN Forty exfoliated primary teeth (Group I) and 40 teeth affected with ECC (Group II) were collected. Unaffected enamel from the ECC group was sampled. Elemental analysis was carried out with energy-dispersive X-ray spectroscopy (EDS), following which the same tooth samples were subjected to amino acid analysis by high-performance liquid chromatography (HPLC). RESULTS Statistically significant differences were observed in the percentage of phosphorus (P) and the Ca/P ratios between the two groups in the elemental analysis. Amino acid analysis revealed no significant difference in the amino acid profile and the quantity of amino acid or protein content between the two groups. CONCLUSIONS This study showed significant differences in the P content and Ca/P ratio between the enamel from teeth with ECC and in that from healthy primary teeth. These findings indicate that differences in the composition of enamel could be a risk factor for ECC.
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Affiliation(s)
- Bhaskar Das
- Department of Pedodontics and Preventive Dentistry, Saveetha University, Chennai, India
| | - Murugan Satta Muthu
- Department of Pedodontics and Preventive Dentistry, Sri Ramachandra University, Chennai, India
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Davis GR, Fearne JM, Sabel N, Norén JG. Microscopic study of dental hard tissues in primary teeth with Dentinogenesis Imperfecta Type II: Correlation of 3D imaging using X-ray microtomography and polarising microscopy. Arch Oral Biol 2015; 60:1013-20. [DOI: 10.1016/j.archoralbio.2015.03.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 03/18/2015] [Accepted: 03/20/2015] [Indexed: 10/23/2022]
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Koubar K, Bekaert V, Brasse D, Laquerriere P. A fast experimental beam hardening correction method for accurate bone mineral measurements in 3D μCT imaging system. J Microsc 2015; 258:241-52. [PMID: 25818096 DOI: 10.1111/jmi.12238] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 02/03/2015] [Indexed: 11/29/2022]
Abstract
Bone mineral density plays an important role in the determination of bone strength and fracture risks. Consequently, it is very important to obtain accurate bone mineral density measurements. The microcomputerized tomography system provides 3D information about the architectural properties of bone. Quantitative analysis accuracy is decreased by the presence of artefacts in the reconstructed images, mainly due to beam hardening artefacts (such as cupping artefacts). In this paper, we introduced a new beam hardening correction method based on a postreconstruction technique performed with the use of off-line water and bone linearization curves experimentally calculated aiming to take into account the nonhomogeneity in the scanned animal. In order to evaluate the mass correction rate, calibration line has been carried out to convert the reconstructed linear attenuation coefficient into bone masses. The presented correction method was then applied on a multimaterial cylindrical phantom and on mouse skeleton images. Mass correction rate up to 18% between uncorrected and corrected images were obtained as well as a remarkable improvement of a calculated mouse femur mass has been noticed. Results were also compared to those obtained when using the simple water linearization technique which does not take into account the nonhomogeneity in the object.
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Affiliation(s)
- Khodor Koubar
- Université de Strasbourg, IPHC, Strasbourg, France.,CNRS, UMR7178, Strasbourg, France
| | - Virgile Bekaert
- Université de Strasbourg, IPHC, Strasbourg, France.,CNRS, UMR7178, Strasbourg, France
| | - David Brasse
- Université de Strasbourg, IPHC, Strasbourg, France.,CNRS, UMR7178, Strasbourg, France
| | - Patrice Laquerriere
- Université de Strasbourg, IPHC, Strasbourg, France.,CNRS, UMR7178, Strasbourg, France
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Abstract
Enamel is unique. It is the only epithelial-derived mineralized tissue in mammals and has a distinct micro- and nanostructure with nanofibrous apatite crystals as building blocks. It is synthesized by a highly specialized cell, the ameloblast, which secretes matrix proteins with little homology to any other known amino acid sequence, but which is composed of a primary structure that makes it competent to self-assemble and control apatite crystal growth at the nanometer scale. The end-product of ameloblast activity is a marvel of structural engineering: a material optimized to provide the tooth with maximum biting force, withstanding millions of cycles of loads without catastrophic failure, while also protecting the dental pulp from bacterial attack. This review attempts to bring into context the mechanical behavior of enamel with the developmental process of amelogenesis and structural development, since they are linked to tissue function, and the importance of controlling calcium phosphate mineralization at the nanometer scale. The origins of apatite nanofibers, the development of a stiffness gradient, and the biological processes responsible for the synthesis of a hard and fracture-resistant dental tissue are discussed with reference to the evolution of enamel from a fibrous composite to a complex, tough, and damage-tolerant coating on dentin.
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Affiliation(s)
- S Habelitz
- Preventive and Restorative Dental Sciences, University of California, San Francisco, CA, USA
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Narrenthran JS, Muthu MS, Renugalakshmi A. In vivo scanning electron microscope assessment of enamel permeability in primary teeth with and without early childhood caries. Caries Res 2015; 49:209-15. [PMID: 25677114 DOI: 10.1159/000367602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2014] [Accepted: 08/12/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Over the years, certain primary teeth have been shown to be highly sensitive to dental caries, while others have remained caries-free. It has been hypothesized that this may be attributed to differences in the permeability of the enamel surface. AIM The aim of the study was to evaluate the hypothesized differences in the permeability of primary tooth enamel in children with and those without Severe Early Childhood Caries (S-ECC) using scanning electron microscopy. MATERIALS AND METHODS Sixteen children between 3 and 6 years of age were randomly selected and divided into two groups: Group 1, children without S-ECC (n = 8), and Group 2, children with S-ECC (n = 8). In each child, 4 teeth (the maxillary right and left central and lateral incisors) were subjected to evaluation. An impression was made with polyvinylsiloxane impression material, and scanning electron microscopy was used to inspect the negative replicas for droplets. RESULTS The results indicated higher significance when individual regions (cervical, middle, and incisal thirds) in the two groups were evaluated and compared. Similarly, the overall results showed high statistical significance between S-ECC and non-S-ECC teeth. CONCLUSION There could be a positive relationship between the permeability of tooth enamel and the development of caries, which needs further research.
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Affiliation(s)
- J S Narrenthran
- Department of Pedodontics and Preventive Dentistry, Sri Ramachandra Dental College and Hospital, Sri Ramachandra University, Porur, Chennai, India
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27
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Chen Y, Fok A. Stress distributions in human teeth modeled with a natural graded material distribution. Dent Mater 2014; 30:e337-48. [DOI: 10.1016/j.dental.2014.08.372] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 05/22/2014] [Accepted: 08/08/2014] [Indexed: 11/26/2022]
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Dong G, Dong Q, Liu Y, Lou B, Feng J, Wang K, Zhou X, Wu H. High-resolution micro-CT scanning as an innovative tool for evaluating dental hard tissue development. J Appl Clin Med Phys 2014; 15:4956. [PMID: 25207426 PMCID: PMC5875498 DOI: 10.1120/jacmp.v15i4.4956] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 04/09/2014] [Indexed: 12/22/2022] Open
Abstract
Microcomputerized tomography (micro‐CT) allows discriminating very small changes in dental hard tissue volumes. The aim of the present study was to create a new method for obtaining high‐resolution, three‐dimensional images of dental hard tissue development using micro‐CT, and to observe the changes in dental hard tissue development and composition in growing rat pups. Tooth germs from rats at the end of the 20‐day embryonic period (E20) and during the neonatal period (D1‐14) were subjected to micro‐CT. Three‐dimensional reconstructions were analyzed to compare dental hard tissue formation and mineralization during the different development periods. Scanning electron microscopy and energy dispersive spectroscopy were used to confirm mineral density (MD). Dental hard tissue began to form during the E20, but the process was slow and resulted in minimal deposition. Hard tissue volume increased by approximately 0.040 mm3/day from E20 to D3, and by 0.12‐0.42 mm3/day after D3, peaking at 0.42 mm3/day at D12. This increase in hard tissue volume resulted in continuous increases in hard tissue thickness, from 90.0 ± 20.7 μm at E20 to 545.2 ± 14.1 μm by D14. MD was 298 ± 3.1 mg HA/cm at E20 and increased to 678.2 ± 6.1 mg HA/cm by D14. The degree of calcification also progressively increased during the first 14 days of development. Dental MD was strongly associated with calcification. This study indicates that micro‐CT is a nondestructive, high‐resolution, reliable, and innovative tool for the evaluation of volume and MD of dental hard tissues during development. Micro‐CT minimizes artifacts caused by sample preparation. PACS number: 87
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29
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Poulter JA, Murillo G, Brookes SJ, Smith CEL, Parry DA, Silva S, Kirkham J, Inglehearn CF, Mighell AJ. Deletion of ameloblastin exon 6 is associated with amelogenesis imperfecta. Hum Mol Genet 2014; 23:5317-24. [PMID: 24858907 PMCID: PMC4168819 DOI: 10.1093/hmg/ddu247] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Amelogenesis imperfecta (AI) describes a heterogeneous group of inherited dental enamel defects reflecting failure of normal amelogenesis. Ameloblastin (AMBN) is the second most abundant enamel matrix protein expressed during amelogenesis. The pivotal role of AMBN in amelogenesis has been confirmed experimentally using mouse models. However, no AMBN mutations have been associated with human AI. Using autozygosity mapping and exome sequencing, we identified genomic deletion of AMBN exon 6 in a second cousin consanguineous family with three of the six children having hypoplastic AI. The genomic deletion corresponds to an in-frame deletion of 79 amino acids, shortening the protein from 447 to 368 residues. Exfoliated primary teeth (unmatched to genotype) were available from family members. The most severely affected had thin, aprismatic enamel (similar to that reported in mice homozygous for Ambn lacking exons 5 and 6). Other teeth exhibited thicker but largely aprismatic enamel. One tooth had apparently normal enamel. It has been suggested that AMBN may function in bone development. No clinically obvious bone or other co-segregating health problems were identified in the family investigated. This study confirms for the first time that AMBN mutations cause non-syndromic human AI and that mouse models with disrupted Ambn function are valid.
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Affiliation(s)
- James A Poulter
- Leeds Institute of Biomedical and Clinical Sciences, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK
| | | | | | - Claire E L Smith
- Leeds Institute of Biomedical and Clinical Sciences, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK
| | - David A Parry
- Leeds Institute of Biomedical and Clinical Sciences, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK
| | - Sandra Silva
- Biology, Molecular Cellular Centre (CBCM), University of Costa Rica, San Pedro, Costa Rica
| | | | - Chris F Inglehearn
- Leeds Institute of Biomedical and Clinical Sciences, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK
| | - Alan J Mighell
- Leeds Institute of Biomedical and Clinical Sciences, St James's University Hospital, University of Leeds, Leeds LS9 7TF, UK School of Dentistry, University of Leeds, Leeds LS2 9LU, UK
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30
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Besinis A, van Noort R, Martin N. Remineralization potential of fully demineralized dentin infiltrated with silica and hydroxyapatite nanoparticles. Dent Mater 2014; 30:249-62. [DOI: 10.1016/j.dental.2013.11.014] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 08/16/2013] [Accepted: 11/25/2013] [Indexed: 11/29/2022]
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31
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Tatara MR, Szabelska A, Krupski W, Tymczyna B, Luszczewska-Sierakowska I, Bieniaś J, Ostapiuk M. Morphometric, densitometric and mechanical properties of mandibular deciduous teeth in 5-month-old Polish Merino sheep. BMC Vet Res 2014; 10:45. [PMID: 24548814 PMCID: PMC3936944 DOI: 10.1186/1746-6148-10-45] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2013] [Accepted: 02/15/2014] [Indexed: 11/10/2022] Open
Abstract
Background Caries, enamel hypoplasia, molar incisor hipomineralization, amylogenesis imperfecta, dentine dysplasia, hypophosphatasia and other dental disorders lead to tooth mineralization disturbances and structural abnormalities, decreasing masticatory organ functions. Dental disorders in sheep can lead to premature slaughter before they have attained final stage of their reproductive life and induce economic loss due to high flock replacement costs. Growth rate, health status and meat quality of sheep depends on tooth properties and quality determining in large extent efficiency of the masticatory apparatus and initial food break up. Considering lack of basic anatomical and physiological data on teeth properties in sheep, the aim of the study was to evaluate morphometric, densitometric and mechanical traits of deciduous mandibular incisor, canine and the second premolar obtained at the slaughter age of 5 months of life. Results The obtained results have shown the highest values of weight, total tooth volume, enamel volume and dentine volume in second premolar. Morphometric and mechanical parameters of incisors reached the highest values in first incisor and decreased gradually in second and third incisor, and in canine. Densitometric measurements have not revealed significant differences of the volumetric tooth mineral density in hard dental tissues between the investigated teeth. Conclusions In conclusion, proposed methodological approach is noninvasive since the deciduous teeth undergo physiological replacement with permanent teeth. Deciduous teeth can be easy collected for analyses from large animal population and may reflect mineral status and metabolism resulting from postnatal growth and development of the whole flock. In individual cases, evaluation of properties of deciduous teeth may serve for breeding selection and further reproduction of sheep possessing favorable traits of teeth and better masticatory system functions.
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Affiliation(s)
- Marcin R Tatara
- Department of Animal Physiology, Faculty of Veterinary Medicine, University of Life Sciences in Lublin, ul, Akademicka 12, 20-950 Lublin Poland.
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Poulter JA, Brookes SJ, Shore RC, Smith CEL, Abi Farraj L, Kirkham J, Inglehearn CF, Mighell AJ. A missense mutation in ITGB6 causes pitted hypomineralized amelogenesis imperfecta. Hum Mol Genet 2013; 23:2189-97. [PMID: 24319098 PMCID: PMC3959822 DOI: 10.1093/hmg/ddt616] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We identified a family in which pitted hypomineralized amelogenesis imperfecta (AI) with premature enamel failure segregated in an autosomal recessive fashion. Whole-exome sequencing revealed a missense mutation (c.586C>A, p.P196T) in the I-domain of integrin-β6 (ITGB6), which is consistently predicted to be pathogenic by all available programmes and is the only variant that segregates with the disease phenotype. Furthermore, a recent study revealed that mice lacking a functional allele of Itgb6 display a hypomaturation AI phenotype. Phenotypic characterization of affected human teeth in this study showed areas of abnormal prismatic organization, areas of low mineral density and severe abnormal surface pitting in the tooth's coronal portion. We suggest that the pathogenesis of this form of AI may be due to ineffective ligand binding of ITGB6 resulting in either compromised cell-matrix interaction or compromised ITGB6 activation of transforming growth factor-β (TGF-β) impacting indirectly on ameloblast-ameloblast interactions and proteolytic processing of extracellular matrix proteins via MMP20. This study adds to the list of genes mutated in AI and further highlights the importance of cell-matrix interactions during enamel formation.
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Affiliation(s)
- James A Poulter
- Leeds Institutes of Molecular Medicine, University of Leeds, Leeds LS9 7TF, UK
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33
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Lynch RJ. The primary and mixed dentition, post-eruptive enamel maturation and dental caries: a review. Int Dent J 2013; 63 Suppl 2:25-30. [DOI: 10.1111/idj.12074] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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34
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Kuscu OO, Sandalli N, Dikmen S, Ersoy O, Tatar I, Turkmen İ, Çaglar E. Association of amoxicillin use and molar incisor hypomineralization in piglets: Visual and mineral density evaluation. Arch Oral Biol 2013; 58:1422-33. [DOI: 10.1016/j.archoralbio.2013.04.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 04/15/2013] [Accepted: 04/23/2013] [Indexed: 10/26/2022]
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35
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McKay S, Farah R, Broadbent JM, Tayles N, Halcrow SE. Is it health or the burial environment: differentiating between hypomineralised and post-mortem stained enamel in an archaeological context. PLoS One 2013; 8:e64573. [PMID: 23734206 PMCID: PMC3667180 DOI: 10.1371/journal.pone.0064573] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 04/16/2013] [Indexed: 12/03/2022] Open
Abstract
Developmental enamel defects are often used as indicators of general health in past archaeological populations. However, it can be difficult to macroscopically distinguish subtle hypomineralised opacities from post-mortem staining, unrelated to developmental defects. To overcome this difficulty, we have used non-destructive x-ray microtomography to estimate the mineral density of enamel. Using a sample of deciduous teeth from a prehistoric burial site in Northeast Thailand, we demonstrate that it is possible to determine whether observed enamel discolourations were more likely to be true hypomineralised lesions or artefacts occurring as the result of taphonomic effects. The analyses of our sample showed no evidence of hypomineralised areas in teeth with macroscopic discolouration, which had previously been thought, on the basis of macroscopic observation, to be hypomineralisations indicative of growth disruption. Our results demonstrate that x-ray microtomography can be a powerful, non-destructive method for the investigation of the presence and severity of hypomineralisation, and that diagnosis of enamel hypomineralisation based on macroscopic observation of buried teeth should be made with caution. This method makes it possible to identify true dental defects that are indicative of growth disruptions.
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Affiliation(s)
- Samantha McKay
- Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | - Rami Farah
- Department of Oral Sciences, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | - Jonathan M. Broadbent
- Department of Oral Rehabilitation, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | - Nancy Tayles
- Department of Anatomy, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - Sian E. Halcrow
- Department of Anatomy, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
- * E-mail:
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36
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Sabel N, Robertson A, Nietzsche S, Norén JG. Demineralization of enamel in primary second molars related to properties of the enamel. ScientificWorldJournal 2012; 2012:587254. [PMID: 22629152 PMCID: PMC3354421 DOI: 10.1100/2012/587254] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Accepted: 12/18/2011] [Indexed: 11/25/2022] Open
Abstract
Enamel structure is of importance in demineralization. Differences in porosity in enamel effect the rate of demineralization, seen between permanent and deciduous teeth. Individual differences have been shown in the mean mineral concentration values in enamel, the role of this in demineralization is not thoroughly investigated. The aim of this study was to study variations of depths of artificial lesions of demineralization and to analyze the depth in relation to variations in the chemical and mineral composition of the enamel. A demineralized lesion was created in second primary molars from 18 individuals. Depths of lesions were then related to individual chemical content of the enamel.
Enamel responded to demineralization with different lesion depths and this was correlated to the chemical composition. The carbon content in sound enamel was shown to be higher where lesions developed deeper. The lesion was deeper when the degree of porosity of the enamel was higher.
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Affiliation(s)
- N Sabel
- Department of Pedodontics, Institute of Odontology at the Sahlgrenska Academy, University of Gothenburg, Box 450, SE-405 30 Göteborg, Sweden.
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Hamba H, Nikaido T, Sadr A, Nakashima S, Tagami J. Enamel Lesion Parameter Correlations between Polychromatic Micro-CT and TMR. J Dent Res 2012; 91:586-91. [DOI: 10.1177/0022034512444127] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Transverse microradiography (TMR) is considered as the gold standard technique for the evaluation of enamel lesions. Micro-computed tomography (µCT) has the advantage of non-destructive measurements, but the beam-hardening effect with polychromatic x-rays is a major drawback. To date, no study has validated µCT against TMR. The objective of this study was to validate µCT measurements of enamel lesions under various x-ray conditions and software beam-hardening correction (BHC) against TMR. Human molars with natural white-spot lesions were scanned for 5 min by µCT at 100 kV in different conditions: 50 µA (0.5-mm Al filter), 165 µA (0.5-mm Al/0.3-mm Cu), and 200 µA (0.5-mm Al/0.4-mm Cu), with or without BHC. Grayscale values were converted into mineral density values using phantoms. Thin sections at the same positions were then prepared for TMR. Lesion depth (LD; µm) and mineral loss (ΔZ; vol%µm) were compared between µCT and TMR by Pearson’s correlations. µCT measurements correlated well with TMR under all conditions (p < 0.001, r > 0.86 for LD and ΔZ), except for 0.5-mm Al without BHC (p > 0.05). Even without BHC, combined Al/Cu filters successfully reduced the beam-hardening effect. µCT can be used as a non-destructive alternative to TMR with comparable parameters for the study of enamel lesions.
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Affiliation(s)
- H. Hamba
- Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
- Global Center of Excellence (GCOE) Program, International Research Center for Molecular Science in Tooth and Bone Diseases at Tokyo Medical and Dental University, Tokyo, Japan
| | - T. Nikaido
- Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - A. Sadr
- Global Center of Excellence (GCOE) Program, International Research Center for Molecular Science in Tooth and Bone Diseases at Tokyo Medical and Dental University, Tokyo, Japan
| | - S. Nakashima
- Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - J. Tagami
- Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
- Global Center of Excellence (GCOE) Program, International Research Center for Molecular Science in Tooth and Bone Diseases at Tokyo Medical and Dental University, Tokyo, Japan
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38
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Watanabe K, Nakamura T, Ogihara T, Ochiai Y, Watanabe S. Longitudinal evaluation of mineral loss at the earliest stage of enamel demineralization using micro-computed tomography. Health (London) 2012. [DOI: 10.4236/health.2012.46055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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39
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Cochrane N, Anderson P, Davis G, Adams G, Stacey M, Reynolds E. An X-ray Microtomographic Study of Natural White-spot Enamel Lesions. J Dent Res 2011; 91:185-91. [DOI: 10.1177/0022034511429570] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022] Open
Abstract
White-spot enamel lesions are an early presentation of dental caries and are ideally managed by non-invasive procedures. The aim of this study was to characterize white-spot enamel lesions by x-ray microtomography. In particular, mineral content across the lesion from the surface to the base of the lesion was measured and surface layers defined. Molars with long buccal white-spot enamel lesions were collected, photographed, and each sectioned to produce 3 500-µm-thick sections. The sections were mounted and imaged by quantitative x-ray microtomography at a 15-µm voxel size. We analyzed line profiles through the middle of each 3D image to determine mineral content and depth. The surface layer thickness of the lesions ranged from 35 to 130 µm, with the maximum mineral content in this layer being 74% to 100% of that of sound enamel. The average mineral content across the lesions ranged from 1.73 to 2.48 g/cm3. No significant differences could be found between lesions clinically categorized as active and those categorized as inactive. However, for depth-matched active and inactive lesions, the active lesions exhibited a more porous surface layer than the inactive lesions. White-spot enamel lesions are highly variable, with surface layers of considerable thickness.
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Affiliation(s)
- N.J. Cochrane
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio 21 Institute, The University of Melbourne, 720 Swanston Street, Melbourne, Victoria 3010, Australia
| | - P. Anderson
- Centre for Oral Growth and Development, Barts and The London, Queen Mary’s School of Medicine and Dentistry, London, E1 4NS, United Kingdom
| | - G.R. Davis
- Centre for Oral Growth and Development, Barts and The London, Queen Mary’s School of Medicine and Dentistry, London, E1 4NS, United Kingdom
| | - G.G. Adams
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio 21 Institute, The University of Melbourne, 720 Swanston Street, Melbourne, Victoria 3010, Australia
| | - M.A. Stacey
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio 21 Institute, The University of Melbourne, 720 Swanston Street, Melbourne, Victoria 3010, Australia
| | - E.C. Reynolds
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio 21 Institute, The University of Melbourne, 720 Swanston Street, Melbourne, Victoria 3010, Australia
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40
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Soviero VM, Leal SC, Silva RC, Azevedo RB. Validity of MicroCT for in vitro detection of proximal carious lesions in primary molars. J Dent 2011; 40:35-40. [PMID: 21930181 DOI: 10.1016/j.jdent.2011.09.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Revised: 09/01/2011] [Accepted: 09/05/2011] [Indexed: 11/25/2022] Open
Abstract
OBJECTIVE This study aimed to validate the MicroCT for detection of proximal carious lesions in primary molars, using histology as the gold standard. METHODS Forty-eight proximal surfaces of primary molars were examined. Two calibrated examiners conducted the examinations independently. Proximal surfaces were visually scored, using ICDAS. Bitewing radiographs, Micro-CT and histological analyses used caries scores: 0=sound; 1=outer enamel; 2=inner enamel; 3=not spread dentine; 4=outer dentine; 5=inner dentine. Axial and sagital images were used for Micro-CT analysis, whilst for histology, tooth sections (400μm) were analyzed stereomicroscopically (×15). RESULTS Inter-examiner agreement ranged from 0.87 to 0.93 kappa coefficient (k). Histological analysis revealed a frequency of sound tooth surfaces (18.8%) enamel carious lesions (E1) (48%) and dentine carious lesions (D1) (33.3%). MicroCT showed high correlation with histology (r(s)0.88). At both diagnostic thresholds (E1 and D1), sensitivity and accuracy were higher for MicroCT. Inter-device agreement between MicroCT and histology was k=0.81. No difference was found between MicroCT and histology as gold standards for detecting carious lesions using ICDAS. CONCLUSION MicroCT can be used as a gold standard for detecting carious lesions in proximal surfaces in primary molars.
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Affiliation(s)
- V M Soviero
- Department of Preventive and Community Dentistry, Universidade do Estado do Rio de Janeiro, Brazil.
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41
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Zou W, Hunter N, Swain MV. Application of polychromatic µCT for mineral density determination. J Dent Res 2010; 90:18-30. [PMID: 20858779 DOI: 10.1177/0022034510378429] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Accurate assessment of mineral density (MD) provides information critical to the understanding of mineralization processes of calcified tissues, including bones and teeth. High-resolution three-dimensional assessment of the MD of teeth has been demonstrated by relatively inaccessible synchrotron radiation microcomputed tomography (SRµCT). While conventional desktop µCT (CµCT) technology is widely available, polychromatic source and cone-shaped beam geometry confound MD assessment. Recently, considerable attention has been given to optimizing quantitative data from CµCT systems with polychromatic x-ray sources. In this review, we focus on the approaches that minimize inaccuracies arising from beam hardening, in particular, beam filtration during the scan, beam-hardening correction during reconstruction, and mineral density calibration. Filtration along with lowest possible source voltage results in a narrow and near-single-peak spectrum, favoring high contrast and minimal beam-hardening artifacts. More effective beam monochromatization approaches are described. We also examine the significance of beam-hardening correction in determining the accuracy of mineral density estimation. In addition, standards for the calibration of reconstructed grey-scale attenuation values against MD, including K(2)PHO(4) liquid phantom, and polymer-hydroxyapatite (HA) and solid hydroxyapatite (HA) phantoms, are discussed.
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Affiliation(s)
- W Zou
- Biomaterials Research Unit, Faculty of Dentistry, University of Sydney, Sydney Dental Hospital, 2 Chalmers Street, Surry Hills, NSW 2010, Australia
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Lo E, Zhi Q, Itthagarun A. Comparing two quantitative methods for studying remineralization of artificial caries. J Dent 2010; 38:352-9. [DOI: 10.1016/j.jdent.2010.01.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2009] [Revised: 01/05/2010] [Accepted: 01/07/2010] [Indexed: 10/20/2022] Open
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Farah RA, Swain MV, Drummond BK, Cook R, Atieh M. Mineral density of hypomineralised enamel. J Dent 2010; 38:50-8. [PMID: 19737596 DOI: 10.1016/j.jdent.2009.09.002] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2009] [Revised: 08/29/2009] [Accepted: 09/01/2009] [Indexed: 10/20/2022] Open
Abstract
OBJECTIVES To characterize molar-incisor hypomineralisation (MIH) defects of different severities quantitatively and qualitatively using X-ray microtomography (XMT) and to measure the range of reduction in mineral density (MD) of MIH enamel compared with the normal range. METHODS Ten sound teeth and ten MIH teeth were scanned using a commercial XMT system. Four hydroxyapatite phantoms of different densities were used as calibration standards with each scan. A calibration equation derived from the phantoms with each tooth was used for MD calibration. MD was traced from the cementum-enamel junction (CEJ) to the cusp tip and from the dentine-enamel junction (DEJ) to the outer enamel surface. RESULTS In sound teeth, MD increased from CEJ to cusp/incisal tip, while in MIH teeth MD dropped from the CEJ to the occlusal region, then increased again at the cusp tip. MD was highest midway between DEJ and outer enamel in sound teeth. In MIH, enamel showed normal thickness and MD was highest near the DEJ and then decreased towards the outer enamel. MD of MIH enamel was on average about 19% lower than sound enamel. The MIH defects seemed to follow the incremental lines of enamel formation. CONCLUSIONS MIH defects are hypomineralised defects of different severities that follow the natural incremental lines of enamel formation. Cuspal areas are usually only mildly affected and cervical enamel always appears to be sound.
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Affiliation(s)
- R A Farah
- Dept of Oral Sciences, Faculty of Dentistry, University of Otago, Dunedin, Otago, New Zealand.
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Kovács M, Danyi R, Erdélyi M, Fejérdy P, Dobó-Nagy C. Distortional effect of beam-hardening artefacts on microCT: a simulation study based on an in vitro caries model. ACTA ACUST UNITED AC 2009; 108:591-9. [PMID: 19778746 DOI: 10.1016/j.tripleo.2009.06.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2009] [Revised: 05/07/2009] [Accepted: 06/15/2009] [Indexed: 11/28/2022]
Abstract
OBJECTIVE The aim of this study was to assess quantitatively the degrading effect of artefacts caused by beam hardening on the microscopic computerized tomography (microCT) measurements of an in vitro caries model. STUDY DESIGN A simulation-based method was described, with which the degrading effect of microCT artefacts on certain parameters of the observed structure could be determined. Simulations were carried out with polychromatic and monochromatic X-ray source, and a linearization method with a second-order polynomial fit algorithm was used in specific cases to correct the beam hardening artefact. The virtual test object was a half-crown of a tooth with an artificial caries lesion. RESULTS For simulation with monochromatic X-ray source, the relative error of lesion depth and thickness measurements of the remineralized layer was found to be 1%-2%. For polychromatic X-ray source, and omitting beam hardening correction, the relative error exceeded 6%. After appropriate beam-hardening correction, the relative error of the measurement could be reduced to 1%-2%. CONCLUSION With the adjustment simulated in this study, microCT having polychromatic X-ray source resulted in the same level of error as with monochromatic source if the linearization method to correct the beam hardening was used. The presented simulation-based method is a useful way to determine artefact-caused distortions for other studies testing objects with different material and geometry.
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Affiliation(s)
- Miklós Kovács
- Independent Section of Radiology, Semmelweis University, Budapest, Hungary.
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45
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Zou W, Gao J, Jones AS, Hunter N, Swain MV. Characterization of a novel calibration method for mineral density determination of dentine by X-ray micro-tomography. Analyst 2009; 134:72-9. [DOI: 10.1039/b806884d] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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46
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Diffusive transport within dentinal tubules: An X-ray microtomographic study. Arch Oral Biol 2008; 53:736-43. [DOI: 10.1016/j.archoralbio.2008.03.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2007] [Revised: 03/11/2008] [Accepted: 03/20/2008] [Indexed: 11/19/2022]
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Abstract
Recent developments in microspatial analysis of enamel chemistry provide the resolution needed to reconstruct detailed chronological records of an individual's early life history. Evidence of nutritional history, residential mobility, and exposure to heavy metals can potentially be retrieved from archaeological and even fossil teeth. Understanding the pattern and timing of incorporation of each trace element or stable isotope into enamel is crucial to the interpretation of the primary data. Here, we use laser ablation inductively coupled plasma mass spectrometry and ArcGIS software to map variation in calcium-normalized strontium intensities across thin sections of enamel from exfoliated deciduous teeth. Differences in calcium-normalized strontium intensities across each tooth reflect variation in tooth mineralization, implying that sampling location must be taken into account in interpreting results. Chronologically consistent shifts in calcium-normalized strontium intensities in teeth from children with known nursing histories reflect the onset and duration of breastfeeding and the introduction of nonmaternal sources of food. This tool is likely to be valuable for studying weaning and nursing behavior in the past. The distribution of normalized strontium intensities presented here is consistent with a model for the differential incorporation of strontium and calcium into enamel during the secretory and maturational phases of formation.
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Huang TTY, Jones AS, He LH, Darendeliler MA, Swain MV. Characterisation of enamel white spot lesions using X-ray micro-tomography. J Dent 2007; 35:737-43. [PMID: 17683844 DOI: 10.1016/j.jdent.2007.06.001] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2007] [Revised: 05/25/2007] [Accepted: 06/03/2007] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVES The aim of this study was to characterise the mineral density (MD) of natural enamel white spot lesions (WSLs) using X-ray micro-tomography calibrated with different density hydroxyapatite phantoms. METHODS Seven natural WSLs from four extracted non-carious premolar teeth were scanned at a voxel size of 7.6 microm using a desktop X-ray micro-tomography system. Five hydroxyapatite phantoms (sintered pellets of hydroxyapatite powder) with densities ranging from 1.52 to 3.14 g/cm(3) were used as calibration standards for each scan. Three-dimensional image reconstruction enabled MD gradients throughout the lesion to be quantified using an MD calibration equation derived from hydroxyapatite phantoms. Background noise generated during the measurement of MD was reduced using a Gaussian filter. RESULTS Gaussian filter reduced the signal-to-noise ratio (standard deviation) significantly while the basic MD information (average value) remained intact. The mineral gradients through the WSLs examined were compared and are discussed in terms of existing literature. The MD of sound enamel, apparent intact surface layer of WSL, and lowest level of WSL was found to be 2.65-2.89 g/cm(3), 2.23-2.58 g/cm(3) and 1.48-2.03 g/cm(3), respectively. Our MD results are comparable with other studies. CONCLUSIONS X-ray micro-tomography is a sensitive in vitro technique capable of characterising and quantifying MD of small non-cavitated WSLs. This method has a promising potential for future carious and quantitative remineralisation studies.
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Affiliation(s)
- Tiffany T Y Huang
- Biomaterials Science Research Unit, Faculty of Dentistry, University of Sydney, NSW, Australia
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Vila Verde A, Ramos MMD, Stoneham AM. The role of mesoscopic modelling in understanding the response of dental enamel to mid-infrared radiation. Phys Med Biol 2007; 52:2703-17. [PMID: 17473346 DOI: 10.1088/0031-9155/52/10/005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Human dental enamel has a porous mesostructure at the nanometre to micrometre scales that affects its thermal and mechanical properties relevant to laser treatment. We exploit finite-element models to investigate the response of this mesostructured enamel to mid-infrared lasers (CO(2) at 10.6 microm and Er:YAG at 2.94 microm). Our models might easily be adapted to investigate ablation of other brittle composite materials. The studies clarify the role of pore water in ablation, and lead to an understanding of the different responses of enamel to CO(2) and Er:YAG lasers, even though enamel has very similar average properties at the two wavelengths. We are able to suggest effective operating parameters for dental laser ablation, which should aid the introduction of minimally-invasive laser dentistry. In particular, our results indicate that, if pulses of approximately 10 micros are used, the CO(2) laser can ablate dental enamel without melting, and with minimal damage to the pulp of the tooth. Our results also suggest that pulses with 0.1-1 micros duration can induce high stress transients which may cause unwanted cracking.
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Affiliation(s)
- A Vila Verde
- Department of Chemical Engineering, Fenske Laboratory, The Pennsylvania State University, University Park, PA 16802, USA
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Humphrey L, Dean M, Jeffries T. An evaluation of changes in strontium/calcium ratios across the neonatal line in human deciduous teeth. VERTEBRATE PALEOBIOLOGY AND PALEOANTHROPOLOGY 2007. [DOI: 10.1007/978-1-4020-5845-5_21] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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