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Xiao S, Li L, Yao J, Wang L, Li K, Yang C, Wang C, Fan Y. Microcracks on the Rat Root Surface Induced by Orthodontic Force, Crack Extension Simulation, and Proteomics Study. Ann Biomed Eng 2021; 49:2228-2242. [PMID: 33686616 DOI: 10.1007/s10439-021-02733-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 01/13/2021] [Indexed: 12/12/2022]
Abstract
Root resorption is a common complication during orthodontic treatment. Microcracks occur on the root surface after an orthodontic force is applied and may be related to the root resorption caused by the orthodontic process. However, the mechanisms underlying root resorption induced by microcracks remain unclear. In this study, a rat orthodontic model was used to investigate the biological mechanisms of root resorption caused by microcracks. First, the first molar was loaded with 0.5-N orthodontic force for 7 days, and microcracks were observed on the root apex surface using a scanning electron microscope. Second, to describe the mechanical principle resulting in microcracks, a finite element model of rat orthodontics was established, which showed that a maximum stress on the root apex can cause microcrack extension. Third, after 7 days of loading in vivo, histological observation revealed that root resorption occurred in the stress concentration area and cementoclasts appeared in the resorption cavity. Finally, proteomics analysis of the root apex area, excluding the periodontal ligament, revealed that the NOX2, Aifm1, and MAPK signaling pathways were involved in the root resorption process. Microcrack extension on the root surface increases calcium ion concentrations, alters the proteins related to root resorption, and promotes cementoclast formation.
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Affiliation(s)
- Shengzhao Xiao
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Chinese Education Ministry, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China
| | - Linhao Li
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Chinese Education Ministry, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China.
| | - Jie Yao
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Chinese Education Ministry, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China
| | - Lizhen Wang
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Chinese Education Ministry, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China
| | - Kaimin Li
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Chinese Education Ministry, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China
| | - Chongshi Yang
- College of Stomatology, Chongqing Medical University, Chongqing, 401147, China
| | - Chao Wang
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Chinese Education Ministry, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China
- College of Stomatology, Chongqing Medical University, Chongqing, 401147, China
| | - Yubo Fan
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Chinese Education Ministry, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China.
- School of Engineering Medicine, Beihang University, Beijing, 100083, China.
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Knaup TJ, Dirk C, Reimann S, Keilig L, Eschbach M, Korbmacher-Steiner H, Bourauel C. Time-dependent behavior of porcine periodontal ligament: A combined experimental, numeric in-vitro study. Am J Orthod Dentofacial Orthop 2018; 153:97-107. [DOI: 10.1016/j.ajodo.2017.05.034] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Revised: 05/01/2017] [Accepted: 05/01/2017] [Indexed: 10/18/2022]
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He Y, Hasan I, Keilig L, Chen J, Pan Q, Huang Y, Bourauel C. Combined implant-residual tooth supported prosthesis after tooth hemisection: A finite element analysis. Ann Anat 2016; 206:96-103. [PMID: 26851558 DOI: 10.1016/j.aanat.2016.01.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 11/25/2015] [Accepted: 01/17/2016] [Indexed: 10/22/2022]
Abstract
Tooth hemisection preserves partial tooth structure and reduces the resorption of alveolar bone. The aim of this study was to analyze the feasibility of preserving a molar after hemisection and inserting a dental implant with different prosthetic superstructures by means of finite element analysis. First, the distance between the root of the mandibular second premolar and the distal root of the first molar were measured in 80 cone beam computed tomography (CBCT) data sets. Based on these data, the lower right posterior jaw segment was reconstructed and the geometries of the appropriate implant were imported. Four models were created: (1) Hemi-1: An implant (3.7×9mm) replaced the mesial root of the molar, and a single crown was placed on the implant and residual tooth. (2) Hemi-2: Two separate crowns were generated for the implant and the residual tooth. (3) Single: An implant (5.5×9mm) with crown replaced the whole molar. (4) FPD: A 3-unit fixed partial denture combined the distal residual part of the molar and premolar. The results indicated that stresses in the cortical bone and strains in the majority region of the spongious bone were below the physiological upper limits. There were higher stresses in implant with the Hemi-1 and Single models, which had the same maximum values of 45.0MPa. The FPD models represented the higher values of stresses in the teeth and strains in PDL compared to other models. From a biomechanical point of view, it can be concluded that a combination of an implant and residual molar after tooth hemisection is an acceptable treatment option.
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Affiliation(s)
- Yun He
- Department of Oral and Maxillofacial Surgery, Hospital of Stomatology, Luzhou Medical College, Jianyangnanlu 2, Luzhou 646000, China; Endowed Chair of Oral Technology, Rheinische Friedrich-Wilhelms University, Welschnonnenstr. 17, Bonn 53111, Germany
| | - Istabrak Hasan
- Endowed Chair of Oral Technology, Rheinische Friedrich-Wilhelms University, Welschnonnenstr. 17, Bonn 53111, Germany; Department of Prosthetic Dentistry, Preclinical Education and Materials Science, Dental School, Rheinische Friedrich-Wilhelms University, Welschnonnenstr. 17, 53111 Bonn, Germany.
| | - Ludger Keilig
- Endowed Chair of Oral Technology, Rheinische Friedrich-Wilhelms University, Welschnonnenstr. 17, Bonn 53111, Germany; Department of Prosthetic Dentistry, Preclinical Education and Materials Science, Dental School, Rheinische Friedrich-Wilhelms University, Welschnonnenstr. 17, 53111 Bonn, Germany
| | - Junliang Chen
- Department of Oral and Maxillofacial Surgery, Hospital of Stomatology, Luzhou Medical College, Jianyangnanlu 2, Luzhou 646000, China
| | - Qing Pan
- Department of Oral and Maxillofacial Surgery, Hospital of Stomatology, Luzhou Medical College, Jianyangnanlu 2, Luzhou 646000, China
| | - Yue Huang
- Department of Orthodontics, Hospital of Stomatology, Luzhou Medical College, Jianyangnanlu 2, Luzhou 646000, China
| | - Christoph Bourauel
- Endowed Chair of Oral Technology, Rheinische Friedrich-Wilhelms University, Welschnonnenstr. 17, Bonn 53111, Germany
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Lee JC, Park JH, Ahn JH, Kim IH, Cho JH, Choi JH, Yoo KY, Lee CH, Hwang IK, Cho JH, Kwon YG, Kim YM, Kang IJ, Won MH. New GABAergic Neurogenesis in the Hippocampal CA1 Region of a Gerbil Model of Long-Term Survival after Transient Cerebral Ischemic Injury. Brain Pathol 2015; 26:581-92. [PMID: 26509872 DOI: 10.1111/bpa.12334] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 10/19/2015] [Indexed: 01/31/2023] Open
Abstract
We investigated the probability of newly generated neurons that could survive and mature in the ischemic hippocampal CA1 region (CA1) of a gerbil model of transient cerebral ischemia. Neuronal death was shown in the stratum pyramidale (SP) from 4 days post-ischemia, and a significant increase in NeuN-positive ((+) ) neurons was found in the SP at 180 days post-ischemia. 5-Bromo-2-deoxyuridine (BrdU)(+) cells were co-stained with NeuN and glutamic decarboxylase 67 (GAD67). Brain-derived neurotrophic factor (BDNF) immunoreactivity and protein level was shown in nonpyramidal cells from 4 days post-ischemia, and the immunoreactivity was strong at 30 days post-ischemia and not significantly changed until 180 days post-ischemia. Furthermore, TrkB immunoreactivity was co-stained with GAD67 when we examined at 180 days post-ischemia. Myelin basic protein (MBP)(+) nerve fibers were reduced at 4 days post-ischemia and maintained until 60 days post-ischemia, and MBP immunoreactivity and levels were significantly increased at 180 days post-ischemia. In the passive avoidance test, cognitive dysfunction was improved at 180 days post-ischemia. These results suggest that the differentiation of neural progenitor cells into new GABAergic neurons may be promoted via BDNF in the ischemic CA1 and that the neurogenesis may partially mediate the recovery of cognitive impairments via increasing myelinated nerve fibers.
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Affiliation(s)
- Jae-Chul Lee
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, 200-701, South Korea
| | - Joon Ha Park
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, 200-701, South Korea
| | - Ji Hyeon Ahn
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, 200-701, South Korea
| | - In Hye Kim
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, 200-701, South Korea
| | - Jeong Hwi Cho
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, 200-701, South Korea
| | - Jung Hoon Choi
- Department of Anatomy, College of Veterinary Medicine, Kangwon National University, Chuncheon, 200-701, South Korea
| | - Ki-Yeon Yoo
- Department of Oral Anatomy, College of Dentistry, Gangneung-Wonju National University, Gangneung, 210-702, South Korea
| | - Choong Hyun Lee
- Department of Pharmacy, College of Pharmacy, Dankook University, Cheonan, 330-714, South Korea
| | - In Koo Hwang
- Department of Anatomy and Cell Biology, College of Veterinary Medicine, and Research Institute for Veterinary Science, Seoul National University, Seoul, 151-742, South Korea
| | - Jun Hwi Cho
- Department of Emergency Medicine, and Institute of Medical Sciences, Kangwon National University Hospital, School of Medicine, Kangwon National University, Chuncheon, 200-701, South Korea
| | - Young-Guen Kwon
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, 120-749, South Korea
| | - Young-Myeong Kim
- Department of Molecular and Cellular Biochemistry, School of Medicine, Kangwon National University, Chuncheon, 200-701, South Korea
| | - Il Jun Kang
- Department of Food Science and Nutrition, Hallym University, Chuncheon, 200-702, South Korea
| | - Moo-Ho Won
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, 200-701, South Korea
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Hasan I, Keilig L, Bourauel C, Lückerath W. The effect of screw preload and framework material on the success of cementable fixed partial prostheses: A finite element study. Ann Anat 2014; 199:58-66. [PMID: 24877686 DOI: 10.1016/j.aanat.2014.03.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 03/07/2014] [Accepted: 03/31/2014] [Indexed: 11/17/2022]
Abstract
The rigidity of framework materials and overload of the implant system directly affect the final transferred load of the bone around implants. The aim of the present study has been to analyse the influence of framework materials on the transferred load to the implant system and the surrounding bone. A finite element model of a long-span cementable implant-supported fixed prosthesis was created with two coping layers (gold and hybrid composite) to optimise the fitting of the prosthesis to the abutments. Three framework materials were analysed: titanium, gold alloy, and zirconia. The connection screws were first preloaded with 200 N. The framework was then loaded with 500 N vertically and at 30° to the framework long axis. Two loading conditions were considered: at the mesial and distal boundaries of the framework and at the centre of the framework. The stresses and strains within the framework materials and bone bed around the supporting implants were analysed. The region and angle of load applications showed an obvious effect on the values of the stresses and strains within the framework itself and, consequently, their distribution in the implant system and surrounding bone. A correlation of the framework material and stresses of the coping materials was observed as well. The gold framework showed acceptable values of stress within the cortical bone (92 MPa and 89 MPa with 30° loading at two points and at the centre, respectively) in comparison to titanium (92 MPa and 113 MPa) and zirconia (88 MPa and 115 MPa).
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Affiliation(s)
- Istabrak Hasan
- Endowed Chair of Oral Technology, Rheinische Friedrich-Wilhelms University, Welschnonnenstr. 17, 53111 Bonn, Germany.
| | - Ludger Keilig
- Endowed Chair of Oral Technology, Rheinische Friedrich-Wilhelms University, Welschnonnenstr. 17, 53111 Bonn, Germany; Department of Prosthetic Dentistry, Preclinical Education and Materials Science, Dental School, Rheinische Friedrich-Wilhelms University, Welschnonnenstr. 17, 53111 Bonn, Germany
| | - Christoph Bourauel
- Endowed Chair of Oral Technology, Rheinische Friedrich-Wilhelms University, Welschnonnenstr. 17, 53111 Bonn, Germany
| | - Walter Lückerath
- Department of Prosthetic Dentistry, Preclinical Education and Materials Science, Dental School, Rheinische Friedrich-Wilhelms University, Welschnonnenstr. 17, 53111 Bonn, Germany
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Favino M, Gross C, Drolshagen M, Keilig L, Deschner J, Bourauel C, Krause R. Validation of a heterogeneous elastic-biphasic model for the numerical simulation of the PDL. Comput Methods Biomech Biomed Engin 2013; 16:544-53. [DOI: 10.1080/10255842.2011.628660] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Papadopoulou K, Hasan I, Keilig L, Reimann S, Eliades T, Jager A, Deschner J, Bourauel C. Biomechanical time dependency of the periodontal ligament: a combined experimental and numerical approach. Eur J Orthod 2013; 35:811-8. [DOI: 10.1093/ejo/cjs103] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Material parameters of the reindeer antler for use in dental implant biomechanics. Ann Anat 2012; 194:518-23. [DOI: 10.1016/j.aanat.2012.02.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2011] [Revised: 02/09/2012] [Accepted: 02/09/2012] [Indexed: 11/24/2022]
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Hasan I, Röger B, Heinemann F, Keilig L, Bourauel C. Influence of abutment design on the success of immediately loaded dental implants: Experimental and numerical studies. Med Eng Phys 2012; 34:817-25. [DOI: 10.1016/j.medengphy.2011.09.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2011] [Revised: 08/19/2011] [Accepted: 09/22/2011] [Indexed: 11/27/2022]
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Huang Y, Keilig L, Rahimi A, Reimann S, Bourauel C. Torque capabilities of self-ligating and conventional brackets under the effect of bracket width and free wire length. Orthod Craniofac Res 2012; 15:255-62. [PMID: 23020696 DOI: 10.1111/j.1601-6343.2012.01553.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVES To numerically investigate the torque capacity of conventional and self-ligating brackets under the effect of varying bracket width and free wire length. MATERIAL AND METHODS Finite element models of three kinds of orthodontic brackets in the 0.022-inch slot size were investigated: Discovery, Damon 3MX, Speed. Additionally, finite element (FE) models of Speed and Damon brackets were generated with the same width as the Discovery. From the left upper incisor to the right upper canine, four brackets each were modelled. The total wire length at the upper right incisor was kept constant at 12 mm for all brackets types. For the Discovery brackets, the wire length was increased from 12 to 16 mm in 2-mm steps. A torque of 20° was applied to the upper right incisor with 0.46 × 0.64 mm(2) (0.018″ × 0.025″) and 0.48 × 0.64 mm(2) (0.019″ × 0.025″) wires. Wires made of stainless steel, titanium molybdenum and nickel titanium were studied. Torque angle/moment characteristics were recorded. RESULTS Wider brackets showed more torque control capability (e.g. Discovery: 10.6 Nmm, Damon: 9.2 Nmm, Speed: 4.0 Nmm for the NiTi wire). Even with the same width as the Discovery bracket, Damon and Speed brackets showed lower torque capability than the Discovery bracket. Increasing the free wire length decreased the torsional stiffness of the wire and thus decreased the torque capability. CONCLUSION The results showed that the bracket design has less influence on the torquing moment than other parameters, such as bracket width, free wire length, wire/slot play or misalignment.
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Affiliation(s)
- Y Huang
- Department of Orthodontics, Hospital of stomatology, Luzhou Medical College, Luzhou, China
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Chatzigianni A, Keilig L, Duschner H, Gotz H, Eliades T, Bourauel C. Comparative analysis of numerical and experimental data of orthodontic mini-implants. Eur J Orthod 2011; 33:468-75. [DOI: 10.1093/ejo/cjr097] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Numeric modeling of torque capabilities of self-ligating and conventional brackets. Am J Orthod Dentofacial Orthop 2009; 136:638-43. [DOI: 10.1016/j.ajodo.2009.04.018] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2008] [Revised: 04/01/2009] [Accepted: 04/01/2009] [Indexed: 11/19/2022]
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Bauer N, Heckmann K, Sand A, Lisson JA. Craniofacial growth patterns in patients with congenitally missing permanent teeth. J Orofac Orthop 2009; 70:139-51. [PMID: 19322532 DOI: 10.1007/s00056-009-0744-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2008] [Accepted: 01/16/2009] [Indexed: 10/21/2022]
Abstract
OBJECTIVE Aim of this study was to investigate any correlations between the congenital absence of certain permanent teeth and individual craniofacial growth patterns. MATERIAL AND METHODS The lateral cephalograms of n = 101 patients (65 female und 36 male) with various congenitally missing teeth were analyzed according to Hasund [11] prior to orthodontic treatment. Cephalometric data to determine the craniofacial growth pattern comprised GntgoAr, NSBa, ML-NSL, NL-NSL, MLNL angles and the index between upper and lower facial heights. Correlations between the type of missing teeth and growth pattern were examined. Group distribution was A = all patients with missing teeth (n = 101), P = missing second premolars (n = 49), S = missing upper lateral incisors (n = 30), X = various missing teeth (n = 22). We included a control group for each of these groups using data from Riolo et al.'s [22] growth study. RESULTS Group A revealed an even distribution with n = 32 patients (31.7%) having a vertical growth pattern, n = 37 patients (36.6%) a neutral growth pattern, and n = 32 patients (31.7%) a horizontal growth pattern. The majority of patients (n = 20, 40.8%) in group P exhibited a horizontal growth pattern, whereas there were no significant correlations between the kind of congenitally missing teeth and growth patterns in groups S and X. Comparison of the mean values of groups P, S and X, revealed no significant differences. When comparing the control group to groups A, P and S, we noted significantly or highly significantly smaller gonial and basal plane angles. No significant differences were apparent concerning group X. CONCLUSIONS This examination demonstrates no statistically-relevant correlation between craniofacial growth pattern and the congenital absence of certain permanent teeth, although horizontal growth is more frequent (but not significant) in patients with congenitally missing second premolars.
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Affiliation(s)
- Natascha Bauer
- Private Orthodontic Practice, Brauerstr. 8, 66663 Merzig/Saar, Germany.
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TAJIMA K, CHEN KK, TAKAHASHI N, NODA N, NAGAMATSU Y, KAKIGAWA H. Three-dimensional finite element modeling from CT images of tooth and its validation. Dent Mater J 2009; 28:219-26. [DOI: 10.4012/dmj.28.219] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Gedrange T, Mai R, Weingaertner J, Hietschold V, Bourauel C, Pradel W, Lauer G, Proff P. Finite element representation of bone substitute remodelling in the jaw bone. ACTA ACUST UNITED AC 2008; 53:220-3. [DOI: 10.1515/bmt.2008.039] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Viecilli R, Katona T, Roberts W. Optimization of microCT data processing for modelling of dental structures in orthodontic studies. Comput Methods Biomech Biomed Engin 2007; 10:257-63. [PMID: 17671859 DOI: 10.1080/10255840701303950] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Dental studies evaluating microCT output often examine resolution as a parameter that affects the data, but many other factors can influence image quality. The objective of this paper is to present the issues involved with the optimization of microCT data acquisition and processing for two biomechanical animal models. The first model evaluates surface and volumetric changes in root structure after in vitro fatigue loading of dog incisors. The second evaluates the in vivo morphometric bone and tooth responses to application of orthodontic force in inbred and transgenic mice. This type of data required specific magnification and noise control microCT settings to segment and render objects with acceptable definition. The proposed procedures enabled high definition rendering of changes in tooth and bone morphology in orthodontic studies. They also allowed for the construction of solid models for finite element analyses.
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Affiliation(s)
- R Viecilli
- Department of Oral Facial Development--Biomechanics Laboratory, Indiana University--Purdue University Indianapolis, Indianapolis, IN 46202, USA.
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Natali AN, Carniel EL, Pavan PG, Bourauel C, Ziegler A, Keilig L. Experimental–numerical analysis of minipig's multi-rooted teeth. J Biomech 2007; 40:1701-8. [PMID: 17074355 DOI: 10.1016/j.jbiomech.2006.08.011] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2006] [Accepted: 08/31/2006] [Indexed: 11/30/2022]
Abstract
The paper pertains to the analysis of the biomechanical behaviour of the periodontal ligament (PDL) by using a combined experimental and numerical approach. Experimental analysis provides information about a two-rooted pig premolar tooth in its socket with regard to morphological configuration and deformational response. The numerical analysis developed for the present investigation adopts a specific anisotropic hyperelastic formulation, accounting for tissue structural arrangement. The parameters to be adopted for the PDL constitutive model are evaluated with reference to data deducted from experimental in vitro tests on different specimens taken from literature. According to morphometric data relieved, solid models are provided as basis for the development of numerical models that adopt the constitutive formulation proposed. A reciprocal validation of experimental and numerical data allows for the evaluation of reliability of results obtained. The work is intended as preliminary investigation to study the correlation between mechanical status of PDL and induction to cellular activity in orthodontic treatments.
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Affiliation(s)
- A N Natali
- Centre of Mechanics of Biological Materials, University of Padova, Italy
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Dalstra M, Cattaneo PM, Beckmann F. Synchrotron radiation-based microtomography of alveolar support tissues. Orthod Craniofac Res 2006; 9:199-205. [PMID: 17101027 DOI: 10.1111/j.1601-6343.2006.00376.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To study the alveolar support structures using synchrotron radiation (SR)-based microtomography with particular focus on the alveolar surface. DESIGN High-resolution microtomography of jaw segments of various species and subsequent three-dimensional (3D) reconstruction. SETTING AND SAMPLE POPULATION Microtomography was performed at the DORIS-ring of the synchrotron facility of HASYLAB/DESY in Hamburg, Germany. The samples consisted of human, simian and porcine jaw segments. RESULTS With SR being monochromatic, no beam-hardening artifacts could occur and the grey values in the scans were therefore directly related to the local tissue densities. Apart from the mineralized tissues, the beam energy was low enough to allow for the visualization of soft tissues like the fibers of the periodontal ligament (PDL) and blood vessels. 3D reconstructions of the alveolar bone showed that it can be rough and sharply edged. Furthermore, an intricate network of marrow cavities and blood vessels penetrates its surface. Differences in the local grey value distribution in the alveolar bone pointed to remodeling activity in the close vicinity of the PDL. CONCLUSION The assumption that the alveolar bone surface is smooth and continuous is not correct. This means that even small orthodontic loads can already give rise to high local stresses and strains in the bone and thus initiate remodeling processes.
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Affiliation(s)
- M Dalstra
- Department of Orthodontics, School of Dentistry, University of Aarhus, Denmark.
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