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Wu C, Mangal U, Seo JY, Kim H, Bai N, Cha JY, Lee KJ, Kwon JS, Choi SH. Enhancing biofilm resistance and preserving optical translucency of 3D printed clear aligners through carboxybetaine-copolymer surface treatment. Dent Mater 2024; 40:1575-1583. [PMID: 39068090 DOI: 10.1016/j.dental.2024.07.009] [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: 02/27/2024] [Revised: 06/30/2024] [Accepted: 07/23/2024] [Indexed: 07/30/2024]
Abstract
OBJECTIVES This study aimed to use a carboxybetaine methacrylate (CBMA) copolymer solution to surface treat 3D printed clear aligners at different fabrication stages, to impart antifouling properties, and assess the surface treatment at various fabrication stages' impact on physico-mechanical characteristics. METHODS Surface treatments using a blend of 2-hydroxyethyl methacrylate (HEMA) and CBMA, termed CCS, were performed at various stages of 3D printed clear aligner fabrication. Experimental groups, CB1, CB2, and CB3, were determined by the stage of surface treatment during post-processing. CB1, CB2, and CB3 received treatment before post-curing, after post-curing, and after post-processing, respectively. Untreated samples served as controls. Physical and mechanical properties were assessed through tensile testing, Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and UV-Vis spectroscopy. The surface was further characterized through scanning electron microscopy and contact angle measurements. The cytotoxicity was assessed with 7-day elution and agar diffusion assays. Lastly, bacterial biofilm resistance was evaluated using confocal laser scanning microscopy. Crystal violet assay was performed using Streptococcus mutans. RESULTS Surface treatment during CB1 stage exerted the most significantly unfavorable influence on properties of the 3D printed aligner resin. CB2 samples showed the maximum preservation of translucency even after 7-day aging. CB2 and CB3 phases showed enhanced hydrophilicity of sample surfaces with reduced adhesion of multispecies biofilm and S. mutans. SIGNIFICANCE Application of CCS surface treatment immediately after post-curing (CB2) can enhance the biofilm resistance of 3D printed clear aligners while maintaining high fidelity to optical translucency and constituent mechanical properties.
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Affiliation(s)
- Chengzan Wu
- Department of Orthodontics, Institute of Craniofacial Deformity, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, Republic of Korea
| | - Utkarsh Mangal
- BK21 FOUR Project, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, Republic of Korea
| | - Ji-Young Seo
- Department of Orthodontics, Institute of Craniofacial Deformity, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, Republic of Korea
| | - Hoon Kim
- Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea
| | - Na Bai
- Department of Prosthodontics, The Affiliated Hospital of Qingdao University, Qingdao University, School of Stomatology of Qingdao University, Qingdao 266000, Shandong, China
| | - Jung-Yul Cha
- Department of Orthodontics, Institute of Craniofacial Deformity, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, Republic of Korea
| | - Kee-Joon Lee
- Department of Orthodontics, Institute of Craniofacial Deformity, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, Republic of Korea
| | - Jae-Sung Kwon
- BK21 FOUR Project, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, Republic of Korea; Department and Research Institute of Dental Biomaterials and Bioengineering, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, Republic of Korea
| | - Sung-Hwan Choi
- Department of Orthodontics, Institute of Craniofacial Deformity, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, Republic of Korea.
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Bhate M, Nagesh S. Assessment of the Effect of Thermoforming Process and Simulated Aging on the Mechanical Properties of Clear Aligner Material. Cureus 2024; 16:e64933. [PMID: 39156374 PMCID: PMC11330653 DOI: 10.7759/cureus.64933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2024] [Accepted: 07/19/2024] [Indexed: 08/20/2024] Open
Abstract
Background Choosing the optimal aligner material on the market is crucial to ensure constant forces for tooth displacement. Processes like manufacturing and intraoral usage can result in the degradation of certain properties, which can affect the overall efficacy of treatment. Objective The objective of the study is to compare the surface roughness and flexural modulus of two aligner materials following the processes of thermoforming and aging. Materials and methods Two groups of 12 samples each were tested: Group 1 consisted of polyethylene terephthalate glycol (PET-G) and Group 2 of zendura-polyurethane (PU). The groups were tested at three time points: T0 - pre-thermoformed; T1 - after thermoforming; T2 - after thermoforming and aging. The surface roughness and the flexural modulus were evaluated. One-way ANOVA followed by a Bonferroni post hoc test was conducted to compare the changes within each group across the three times. An independent t-test was done to compare the values between the two groups at each time point. The statistical tests were performed using SPSS software version 26 (IBM Corp., Armonk, NY, USA). P-values >0.05 were considered statistically significant. Results There was a significant change in the surface roughness post-aging in Group 2 (p=0.03) and flexural strength within Group 1 (p=0.031) and Group 2 (p=0.06) across the three time points. Comparing the changes within the three time points in Group 1, significant changes were observed between T0-T1 (p=0.045) and T0-T2 (p=0.07). In Group 2, significant changes were observed between T0-T2 (p=0.012). Comparing the flexural strength between the two groups, significant differences were observed at T0 (p=0.012) and T1 (p=0.001). Conclusion The aging process affected the surface roughness in Zendura (PU). The thermoforming and aging process resulted in reduced flexural strength in both Zendura (PU) and Duran groups (PET-G).
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Affiliation(s)
- Manjiri Bhate
- Orthodontics and Dentofacial Orthopedics, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, IND
| | - Shweta Nagesh
- Orthodontics and Dentofacial Orthopedics, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, IND
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Colonna A, Lobbezoo F, Gravili G, Lombardo L, Ahlberg J, Manfredini D. Effects of orthodontic aligners on 24-hour masseter muscle activity: a multiple-day electromyographic study. Cranio 2024:1-10. [PMID: 38840500 DOI: 10.1080/08869634.2024.2357054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2024]
Abstract
OBJECTIVE This study aimed to assess the effects of aligners on masseter muscle activity by using an electromyographic device in the home environment. METHODS The study was performed on healthy patients who required orthodontic treatment. Three different 24 h-EMG recording sessions were performed in different conditions: without aligners, with passive aligners, and with active aligners. The non-functional MMA work index (nfMMA-WI) and the non-functional MMA time index (nfMMA-TI) for both awake and sleep hours were assessed. ANOVA test was used to compare the average activity during the three recording conditions. RESULTS On average, a total recording time of 204.7 ± 7.9 hours were provided for each patient. For most patients, ANOVA test showed an absence of significant differences between the recording sessions. CONCLUSIONS The impact of our results is not negligible: clinicians can find remarkable support to the hypothesis that the use of aligners affects the MMA only in a minority of subjects.
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Affiliation(s)
- A Colonna
- School of Dentistry, Department of Medical Biotechnologies, University of Siena, Siena, Italy
- Postgraduate School of Orthodontics, University of Ferrara, Ferrara, Italy
| | - F Lobbezoo
- Department of Orofacial Pain and Dysfunction, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - G Gravili
- Postgraduate School of Orthodontics, University of Ferrara, Ferrara, Italy
| | - L Lombardo
- Postgraduate School of Orthodontics, University of Ferrara, Ferrara, Italy
| | - J Ahlberg
- Department of Oral and Maxillofacial, Diseases, University of Helsinki, Helsinki, Finland
| | - D Manfredini
- School of Dentistry, Department of Medical Biotechnologies, University of Siena, Siena, Italy
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Barile C, Cianci C, Paramsamy Kannan V, Pappalettera G, Pappalettere C, Casavola C, Suriano C, Ciavarella D. Thermoplastic clear dental aligners under cyclic compression loading: A mechanical performance analysis using acoustic emission technique. J Mech Behav Biomed Mater 2024; 152:106451. [PMID: 38310814 DOI: 10.1016/j.jmbbm.2024.106451] [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: 12/19/2023] [Revised: 01/26/2024] [Accepted: 01/30/2024] [Indexed: 02/06/2024]
Abstract
The objective of this work is to analyse the performance of clear aligners made of thermoplastic materials. Within this framework, the damage evolution stages and damage states of the aligners at different cycles of the compressive loading are evaluated using the Acoustic Emission (AE) technique. Three different clear aligner systems were prepared: thermoformed PET-g (polyethylene terephthalate glycol) and PU (polyurethane), and additively manufactured PU. Cyclic compression tests are performed to simulate 22500 swallows. The mechanical results show that the energy absorbed by the thermoformed PET-g aligner remains stable around 4 Nmm throughout the test. Although the PU-based aligners show a higher energy absorption of about 7 Nmm during the initial phase of the cyclic loading, this gradually decreases after 12500 cycles. The time-domain based, and frequency-based parameters of the stress wave acoustic signals generated by the aligners under compression loading are used to identify the damage evolution stages. The machine learning-based AE results reveal the initiation and termination of the different damage states in the aligners and the frequency-based results distinguish the different damage sources. Finally, the microscopy results validated the damage occurrences in the aligners identified by the AE results. The mechanical test results indicate that the thermoformed PET-g has the potential to match the performance and requirements of the dentistry of the popular Invisalign (additively manufactured PU). The AE results have the potential to identify at which cycles the aligners may start losing their functionality.
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Affiliation(s)
- Claudia Barile
- Dipartimento di Meccanica, Matematica e Management, Politecnico di Bari, Bari, Italy
| | - Claudia Cianci
- Dipartimento di Meccanica, Matematica e Management, Politecnico di Bari, Bari, Italy
| | | | - Giovanni Pappalettera
- Dipartimento di Meccanica, Matematica e Management, Politecnico di Bari, Bari, Italy.
| | - Carmine Pappalettere
- Dipartimento di Meccanica, Matematica e Management, Politecnico di Bari, Bari, Italy
| | - Caterina Casavola
- Dipartimento di Meccanica, Matematica e Management, Politecnico di Bari, Bari, Italy
| | - Carmela Suriano
- Dipartimento di Medicina Sperimentale e Clinica, Università di Foggia, Foggia, Italy
| | - Domenico Ciavarella
- Dipartimento di Medicina Sperimentale e Clinica, Università di Foggia, Foggia, Italy
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Geramy A, Safari F. Effect of clear aligner type on maxillary full-arch intrusion: 3D analysis using finite element method. BMC Oral Health 2024; 24:231. [PMID: 38350943 PMCID: PMC10865575 DOI: 10.1186/s12903-024-03984-6] [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: 09/26/2023] [Accepted: 02/05/2024] [Indexed: 02/15/2024] Open
Abstract
BACKGROUND Vertical maxillary excess (VME) is one of the most common reasons for seeking orthodontic treatment. Total intrusion with aligners is a promising alternative to surgery in some cases. Considering the elastic deformation of aligners, this study aimed to evaluate the possible desirable and undesirable teeth displacements during full maxillary arch intrusion using clear aligners and temporary anchorage devices (TADs). METHODS The maxillary arch and clear aligners were modeled in SolidWorks. Four aligner brands including Leon, Duran, Duran Plus, and Essix Plus were selected based on their material properties. Anterior and posterior intrusion forces of 80 and 300 g were applied from attachments between the canines and first premolars and between the first and second molars, respectively. Vertical and anteroposterior tooth displacements were determined. RESULTS The greatest intrusion was recorded at the buccal of the second molar, followed by the first molar. The lowest value was measured at the palatal of the molars with all aligners except Duran, which indicated minimal intrusion in the central incisor. All teeth were mesially displaced at the incisal/occlusal except incisors that moved distally. All apices showed distal movement. CONCLUSIONS Total intrusion using clear aligners may be accompanied by other tooth movements, including buccal tipping and mesial-in rotation of the molars, retrusion of incisors, and mesial movement of other teeth.
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Affiliation(s)
- Allahyar Geramy
- Department of Orthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
| | - Fatemeh Safari
- Department of Orthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
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Cen X, Pan X, Wang R, Huang X, Zhao Z. The complex of tannic acid and cetylpyridinium chloride: An antibacterial and stain-removal cleaner for aligners. Am J Orthod Dentofacial Orthop 2024; 165:173-185. [PMID: 37906245 DOI: 10.1016/j.ajodo.2023.08.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 08/01/2023] [Accepted: 08/01/2023] [Indexed: 11/02/2023]
Abstract
INTRODUCTION Effective aligner hygiene is recognized as an important part of orthodontic treatments and oral hygiene. However, there is no effective cleansing method for removable aligners. METHODS In this study, we incorporated tannic acid (TA) with cetylpyridinium chloride (CPC) to develop the TA-CPC complex. The antibacterial properties of 15.8 mg/mL TA-CPC against Escherichia coli and Staphylococcus aureus were evaluated in vitro, which were compared with 5.1 mg/mL TA, 10.7 mg/mL CPC, a commercial denture cleansing solution (YA; 15 mg/mL), and water. As for the assessment of stain-removal ability, the aligners stained by coffee were soaked in cleansing solutions, and the color changes (ΔE∗) were calculated on the basis of the CIE L∗a∗b∗ color system, and the National Bureau of Standards system was used for the clinical interpretation of the color change. Atomic force microscope examination, tensile property assessment, and wavelength dispersive x-ray fluorescence analysis were performed to investigate the material compatibility of TA-CPC, and Cell Counting Kit-8 assay and live/dead assay were used to test the cytotoxicity of TA-CPC. RESULTS The results showed that TA-CPC had a positive zeta-potential, and cation-π interaction changed the chemical environments of the phenyl group in TA-CPC, resulting in greater inhibition zones of S. aureus and E. coli than other cleaners. The quantification of the biofilm biomass and the fluorescent intensities also reflected that the TA-CPC solution exhibited better antibacterial ability. As for the ability of stain removal, ΔE∗ value of group TA-CPC was 2.84 ± 0.55, whereas those of stained aligners immersed with deionized distilled water, TA, YA, and CPC were 10.26 ± 0.04, 9.54 ± 0.24, 5.93 ± 0.36, and 4.69 ± 0.35, respectively. The visual inspection and National Bureau of Standards ratings also showed that the color of stained aligners cleansed by TA-CPC was much lighter than those of the other groups. Meanwhile, TA-CPC had good compatibility with the aligner material and cells. CONCLUSIONS TA-CPC is a promising strategy to inhibit the formation of biofilms and remove the stains on the aligners safely, which may disinfect the aligners to improve oral health and help keep the transparent appearances of aligners without impacting the morphology and mechanical properties.
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Affiliation(s)
- Xiao Cen
- State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Xuefeng Pan
- State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Rong Wang
- Zhejiang International Scientific and Technological Cooperative Base of Biomedical Materials and Technology, Zhejiang Engineering Research Center for Biomedical Materials, Cixi Institute of Biomedical Engineering, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, China.
| | - Xinqi Huang
- State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
| | - Zhihe Zhao
- State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
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Nicita F, D'Amico C, Filardi V, Spadaro D, Aquilio E, Mancini M, Fiorillo L. Chemical-Physical Characterization of PET-G-Based Material for Orthodontic Use: Preliminary Evaluation of micro-Raman Analysis. Eur J Dent 2024; 18:228-235. [PMID: 37247624 PMCID: PMC10959632 DOI: 10.1055/s-0043-1764424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023] Open
Abstract
OBJECTIVES Orthodontic treatment with clear thermoplastic aligners is in great demand by patients especially for aesthetics. Any alterations in the chemical composition of the thermoplastic material for aligners, subjected to the oral environment and exposure to various commonly used substances, could influence the desired orthodontic movement decreasing the predictability of the treatment. The objective of this study was to determine the chemical-physical characterization by micro-Raman spectroscopy of a thermoplastic material based on polyethylene terephthalate glycol (PET-G) used for the manufacture of Lineo aligners (Micerium Lab, Avegno, Italy) subjected to different staining beverages and cleaning agents. MATERIALS AND METHODS Twenty-two thermoformed PET-G samples were immersed to various substances of daily use for 10 and 15 days (coffee, tea, Coca-Cola, red wine, colloidal silver disinfectant, nicotine, artificial saliva, cigarette smoke, and different combinations of saliva with some of the previous solutions). Subsequently, the chemical-physical characterization was investigated by micro-Raman spectroscopy. RESULTS The analysis of the spectra acquired for all the specimens showed no difference in the exposure to the different solvents at 10 and 15 days. Furthermore, having ascertained the heterogeneous surface morphology of the PET-G material due to thermoforming, various deposits were present on all the samples whose consistency and concentration depended on the substance used. CONCLUSION The spectroscopic investigations have provided a precise and detailed analysis of the qualitative and structural data of the PET-G material under examination. No significant structural modifications of the thermoplastic polymer were found after immersion in different solutions in the exposure times adopted.
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Affiliation(s)
- Fabiana Nicita
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, via Consolare Valeria, Messina, Italy
| | - Cesare D'Amico
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, via Consolare Valeria, Messina, Italy
| | - Vincenzo Filardi
- D.A. Research and Internationalization, University of Messina, Via Consolato del mare 41, Messina, Italy
| | | | | | - Maura Mancini
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, via Consolare Valeria, Messina, Italy
| | - Luca Fiorillo
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, via Consolare Valeria, Messina, Italy
- Multidisciplinary Department of Medical-Surgical and Dental Specialties, University of Campania Luigi Vanvitelli, Naples, Italy
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Ravuri P, Kubavat AK, Rathi V, Luke John T, Varma PK, Mujoo S, Somaraj V. Effectiveness and Biocompatibility of Tooth Aligners Made from Polyethylene Terephthalate Glycol (PeT-G), Polypropylene (PP), Polycarbonate (PC), Thermoplastic Polyurethanes (TPUs), and Ethylene-Vinyl Acetate (EVA): A Systematic Review. JOURNAL OF PHARMACY AND BIOALLIED SCIENCES 2024; 16:S93-S96. [PMID: 38595485 PMCID: PMC11001044 DOI: 10.4103/jpbs.jpbs_883_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 09/19/2023] [Accepted: 09/23/2023] [Indexed: 04/11/2024] Open
Abstract
Objective This systematic review examines the efficacy and biocompatibility of orthodontic clear aligner tooth aligners constructed from polyethylene terephthalate glycol (PeT-G), polypropylene (PP), polycarbonate (PC), thermoplastic polyurethanes (TPUs), and ethylene-vinyl acetate (EVA). Materials and Methods To find relevant papers published through September 2021, PubMed was searched extensively. Randomized clinical trials (RCTs) and observational studies assessing the effectiveness and biocompatibility of the aligner materials were included. Data were extracted independently, and the quality of included research was appraised using relevant procedures. The research variability necessitated a narrative synthesis. Results Five studies were included for comparison. All materials were biocompatible; however, PeT-G and EVA aligners caused the least tissue irritation. Patients preferred TPU aligners for initial comfort and PeT-G aligners for transparency and endurance. Conclusion Biocompatible PeT-G, PP, PC, TPU, and EVA tooth aligners fix malocclusions. Aligner materials should be chosen based on patient preferences, treatment goals, and material qualities. For stronger proof, a longer-term study is needed.
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Affiliation(s)
- Preetham Ravuri
- Department of Orthodontics and Dentofacial Orthopedics, Narsinhbhai Patel Dental College and Hospital, Sankalchand Patel University, Visnagar, Gujarat, India
| | - Ajay K. Kubavat
- Department of Orthodontics and Dentofacial Orthopedics, Narsinhbhai Patel Dental College and Hospital, Sankalchand Patel University, Visnagar, Gujarat, India
| | - Vipul Rathi
- Department of Orthodontics and Dentofacial Orthopedics, VYWS Dental College and Hospital, Amravati, Maharashtra, India
| | - T. Luke John
- Department of Orthodontics and Dentofacial Orthopeadics, Anil Neerukonda Institute of Dental Sciences, Sangivalasa, Visakhapatnam, Andhra Pradesh, India
| | - Praveen K. Varma
- Department of Orthodontics, Vishnu Dental College, Vishnupur, Bhimavaram, Andhra Pradesh, India
| | - Sheetal Mujoo
- Division of Oral Medicine and Radiology, College of Dentistry, Jazan University, Jazan, Saudi Arabia
| | - Vinej Somaraj
- Department of Public Health Dentistry, Rajas Dental College and Hospital, Tirunelveli, Tamil Nadu, India
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Staderini E, Chiusolo G, Guglielmi F, Papi M, Perini G, Tepedino M, Gallenzi P. Effects of Thermoforming on the Mechanical, Optical, Chemical, and Morphological Properties of PET-G: In Vitro Study. Polymers (Basel) 2024; 16:203. [PMID: 38257002 PMCID: PMC10820839 DOI: 10.3390/polym16020203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 12/30/2023] [Accepted: 12/30/2023] [Indexed: 01/24/2024] Open
Abstract
The effectiveness of clear aligners in correcting malocclusions is closely linked to the properties of the materials used to make them. The polymers used in the manufacture of clear aligners have well-established properties. However, the process of manufacturing clear aligners, known as thermoforming, involves thermal and mechanical shocks that may alter these properties. The objective of this study was to evaluate the effects of thermoforming on the mechanical, optical, chemical, and morphological properties of sixty PET-G specimens. The study compared the thickness, weight, absorbance, chemical structure, surface roughness, elastic modulus, yield strength, and breaking load of thirty thermoformed specimens with thirty non-thermoformed specimens. The study introduces a new approach by using standardized samples to analyze both chemical and physical properties. The results showed statistically significant differences in thickness (-15%), weight (-11%), and surface roughness (+1233% in roughness average; +1129% in RMS roughness) of the material. Additionally, a correlation was found between reduction in thickness and increase in opalescence. There was no significant change in the functionality of the aligners after thermoforming, as no significant mechanical changes were found. However, the increase in surface roughness may lead to plaque and fluid accumulation and worsen the fit of the aligners.
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Affiliation(s)
- Edoardo Staderini
- School of Dentistry, Dean: Prof. Massimo Cordaro, Catholic University of the Sacred Heart, IRCCS “A. Gemelli” University Polyclinic Foundation, Largo Agostino Gemelli 8, 00168 Rome, Italy; (E.S.); (G.C.); (P.G.)
- Postgraduate School of Orthodontics–Director: Prof. Massimo Cordaro, Catholic University of the Sacred Heart, Largo Agostino Gemelli 8, 00168 Rome, Italy
| | - Giuseppe Chiusolo
- School of Dentistry, Dean: Prof. Massimo Cordaro, Catholic University of the Sacred Heart, IRCCS “A. Gemelli” University Polyclinic Foundation, Largo Agostino Gemelli 8, 00168 Rome, Italy; (E.S.); (G.C.); (P.G.)
| | - Federica Guglielmi
- School of Dentistry, Dean: Prof. Massimo Cordaro, Catholic University of the Sacred Heart, IRCCS “A. Gemelli” University Polyclinic Foundation, Largo Agostino Gemelli 8, 00168 Rome, Italy; (E.S.); (G.C.); (P.G.)
- Postgraduate School of Orthodontics–Director: Prof. Massimo Cordaro, Catholic University of the Sacred Heart, Largo Agostino Gemelli 8, 00168 Rome, Italy
| | - Massimiliano Papi
- Department of Neurosciences, Catholic University of the Sacred Heart, Largo Francesco Vito 1, 00168 Rome, Italy; (M.P.); (G.P.)
- IRCCS “A. Gemelli” University Polyclinic Foundation, Largo Agostino Gemelli 8, 00168 Rome, Italy
| | - Giordano Perini
- Department of Neurosciences, Catholic University of the Sacred Heart, Largo Francesco Vito 1, 00168 Rome, Italy; (M.P.); (G.P.)
- IRCCS “A. Gemelli” University Polyclinic Foundation, Largo Agostino Gemelli 8, 00168 Rome, Italy
| | - Michele Tepedino
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, Piazza Santa Margherita 2, 67100 L’Aquila, Italy
| | - Patrizia Gallenzi
- School of Dentistry, Dean: Prof. Massimo Cordaro, Catholic University of the Sacred Heart, IRCCS “A. Gemelli” University Polyclinic Foundation, Largo Agostino Gemelli 8, 00168 Rome, Italy; (E.S.); (G.C.); (P.G.)
- Postgraduate School of Orthodontics–Director: Prof. Massimo Cordaro, Catholic University of the Sacred Heart, Largo Agostino Gemelli 8, 00168 Rome, Italy
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10
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Cintora-López P, Arrieta-Blanco P, Martin-Vacas A, Paz-Cortés MM, Gil J, Aragoneses JM. In vitro analysis of the influence of the thermocycling and the applied force on orthodontic clear aligners. Front Bioeng Biotechnol 2023; 11:1321495. [PMID: 38173871 PMCID: PMC10761475 DOI: 10.3389/fbioe.2023.1321495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Accepted: 12/11/2023] [Indexed: 01/05/2024] Open
Abstract
The mechanical properties of polyurethane dental aligners have been studied in an oral environment at 37°C and subjected to thermal cycling between 5°C and 55°C for long periods of time at different mechanical stresses. The aim is to determine the efficacy of the orthodontic aligner at different stress levels, the effect of thermal cycling with therapy time on tooth position correction. Sixty aligners with the same design were studied applying tensions of 0, 3 and 30 N and determining the deformation at different times from 1 to 760 h. Half of these aligners were subjected to stresses submerged in artificial saliva at 37°C and the other half were subjected to thermal cycles between 2°C and 55°C in salivary medium. Deformation was determined using a high-resolution stereo magnifier and ImageJ image analysis software. Water adsorption by the polyurethane was determined at the different test times. The results showed that in the unloaded aligners there is no appreciable deformation, but with thermal cycling there is a light shrinkage of the aligner due to the semi-crystallization process (ordering of polymeric chains) of the polyurethane. When applying loads of 3 and 30 N, creep curves with constant deformation transition zones can be seen. The transition zones decrease as the applied mechanical load increases. In addition, the significant effect of thermal cycling on the reduction of the transition zone of the aligners has been demonstrated. The transition zones are optimal for dental correction as constant stresses are exerted for tooth movement. The effect of thermal cycling shortens the constant deformation zone and reduces tooth alignment time. It was observed that the absorption of water in the aligner is constant after 1 h of immersion and does not exceed 0.4% by weight of absorbed water.
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Affiliation(s)
| | | | - Andrea Martin-Vacas
- Faculty of Dentistry, Alfonso X El Sabio University, Villanueva de la Cañada, Spain
| | | | - Javier Gil
- Faculty of Medicine and Health Sciences, Bionegineering Institute of Technology, International University of Catalunya, Barcelona, Spain
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Bichu YM, Alwafi A, Liu X, Andrews J, Ludwig B, Bichu AY, Zou B. Advances in orthodontic clear aligner materials. Bioact Mater 2023; 22:384-403. [PMID: 36311049 PMCID: PMC9588987 DOI: 10.1016/j.bioactmat.2022.10.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 10/05/2022] [Accepted: 10/06/2022] [Indexed: 11/24/2022] Open
Abstract
Rapid technological improvements in biomaterials, computer-aided design (CAD) and manufacturing (CAM) have endorsed clear aligner therapy (CAT) as a mainstay of orthodontic treatment, and the materials employed for aligner fabrication play an all-important role in determining the clinical performance of clear aligners. This narrative review has attempted to comprehensively encompass the entire gamut of materials currently used for the fabrication of clear aligners and elucidate their characteristics that are crucial in determining their performance in an oral environment. Historical developments and current protocols in aligner fabrication, features of contemporary bioactive materials, and emerging trends related to CAT are discussed. Advances in aligner material chemistry and engineering possess the potential to bring about radical transformations in the therapeutic applications of CAT; in the absence of which, clear aligners would continue to underperform clinically, due to their inherent biomechanical constraints. Finally, while innovations in aligner materials such as shape memory polymers, direct three-dimensional (3D) printed clear aligners and bioactive materials combined with clear aligner materials are essential to further advance the applications of CAT; increased awareness of environmental responsibilities among aligner manufacturers, aligner prescribing clinicians and aligner users is essential for better alignment of our climate change goals towards a sustainable planet.
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Affiliation(s)
| | - Abdulraheem Alwafi
- Department of Oral Health Science, Faculty of Dentistry, University of British Columbia, Vancouver, Canada
- Faculty of Dentistry, Department of Dental Public Health, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Xiaomo Liu
- Department of Orthodontics, Peking University School and Hospital of Stomatology, Beijing, China
| | | | - Björn Ludwig
- Department of Orthodontics, University of Homburg, Saar, Germany
| | | | - Bingshuang Zou
- Department of Oral Health Science, Faculty of Dentistry, University of British Columbia, Vancouver, Canada
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12
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Iliadi A, Enzler V, Polychronis G, Peltomaki T, Zinelis S, Eliades T. Εffect of cleansers on the composition and mechanical properties of orthodontic aligners in vitro. Prog Orthod 2022; 23:54. [PMID: 36517652 PMCID: PMC9751251 DOI: 10.1186/s40510-022-00449-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 11/09/2022] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND The aim of the study was to investigate the effect of three aligner cleaners on the composition and mechanical properties of two types of orthodontic aligners. MATERIALS AND METHODS The cleaners tested were two alkaline peroxide solutions (Retainer Brite-RB; Retainer Cleaner-RC) and one peroxide-free (Steraligner-ST) and the aligners Clear Aligner (C, polyester) and Invisalign (I, polyester-urethane). The aligners were immersed in the cleaner solutions as instructed every day (15 min for RB, RC; 5 min for ST) for a two-week period. The acidity of the solutions was tested with a pH meter. The changes in the chemical composition of the aligners were studied by attenuated total-reflection Fourier transform infrared spectrometry (ATR-FTIR), while Instrumented Indentation Testing (IIT) was used for assessment of changes in Martens Hardness (HM), modulus (EIT), elastic index (nIT) and relaxation (RIT). RESULTS RB and RC were weakly acidic (pH = 6.3), whereas ST was mildly acidic (pH = 4.8). The ATR-FTIR analysis demonstrated evidence of acidic hydrolysis of C in ST and I in RB. The IIT-derived properties of I were not affected by the cleaners. However, for C a significant change was found in HM (all cleaners), nIT (all cleaners) and RIT (RB, ST). Although the chemical changes support a hydrolytic material deterioration, the results of mechanical properties may interfere with the material residual stresses during fabrication. CONCLUSIONS Caution should be exerted in the selection of aligner cleaners. The mild acidic cleanser was more aggressive to the polyester, whereas an alkaline peroxide to the polyester-urethane aligner.
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Affiliation(s)
- Anna Iliadi
- grid.5216.00000 0001 2155 0800Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Vera Enzler
- grid.7400.30000 0004 1937 0650Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, Plattenstrasse 11, 8032 Zurich, Switzerland
| | - Georgios Polychronis
- grid.5216.00000 0001 2155 0800Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Timo Peltomaki
- grid.502801.e0000 0001 2314 6254Department of Oral and Maxillofacial Diseases, Tampere University Hospital, Tampere, Finland Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland ,grid.410705.70000 0004 0628 207XDepartment of Oral and Maxillofacial Diseases, Kuopio University Hospital, Kuopio, Finland ,grid.9668.10000 0001 0726 2490Faculty of Health Sciences, Institute of Dentistry, University of Eastern Finland, Kuopio, Finland
| | - Spiros Zinelis
- grid.5216.00000 0001 2155 0800Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Theodore Eliades
- grid.7400.30000 0004 1937 0650Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, Plattenstrasse 11, 8032 Zurich, Switzerland
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Arveda N, Colonna A, Palone M, Lombardo L. Aligner hybrid orthodontic approach to treat severe transverse divergence in an adolescent girl: A case report. Int Orthod 2022; 20:100686. [PMID: 36096935 DOI: 10.1016/j.ortho.2022.100686] [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: 07/24/2022] [Revised: 08/13/2022] [Accepted: 08/15/2022] [Indexed: 11/16/2022]
Abstract
OBJECTIVE To resolve a complex Class II case with unilateral crossbite through an aesthetic approach, namely a hybrid orthodontic treatment combining aligners with miniscrews and auxiliaries. MATERIALS AND METHODS A 14-year-old hypodivergent female patient with dental Class II and posterior crossbite presented for orthodontic treatment. The patient refused conventional fixed multibracket treatment and was therefore prescribed aligners used in association with miniscrews and sectional lingual appliances. Pre- and post-treatment records and 2-year follow-up records are presented. RESULTS Treatment objectives, namely ideal occlusion and improved profile, were achieved in 12 months. Post-treatment panoramic radiography showed good root parallelism, and no sign of either crestal bone height reduction or apical root resorption. The patient was satisfied with the functional and aesthetic outcomes, which were stable at 2 years. CONCLUSION This case report illustrates that a hybrid aligner approach may be used to treat posterior crossbite and class II malocclusion with reduced treatment times, optimal oral hygiene and excellent aesthetics.
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Affiliation(s)
- Niki Arveda
- University of Ferrara, Postgraduate school of Orthodontics, Ferrara, Italy
| | - Anna Colonna
- University of Ferrara, Postgraduate school of Orthodontics, Ferrara, Italy.
| | - Mario Palone
- University of Ferrara, Postgraduate school of Orthodontics, Ferrara, Italy
| | - Luca Lombardo
- University of Ferrara, Postgraduate school of Orthodontics, Ferrara, Italy
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Warnecki M, Sarul M, Kozakiewicz M, Zięty A, Babiarczuk B, Kawala B, Jurczyszyn K. Surface Evaluation of Aligners after Immersion in Coca-Cola and Orange Juice. MATERIALS (BASEL, SWITZERLAND) 2022; 15:ma15186341. [PMID: 36143665 PMCID: PMC9504463 DOI: 10.3390/ma15186341] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 09/09/2022] [Accepted: 09/12/2022] [Indexed: 05/31/2023]
Abstract
Orthodontic removable appliances made of transparent thermoplastic materials-aligners-are becoming increasingly popular in contemporary orthodontic practice. It is important for the clinician to fully understand the mechanical properties and behavior of the appliance used. Because of that, the aim of our study was to investigate the changes in aligner surface after immersion in Coca-Cola and orange juice. For surface evaluation, fractal analysis, texture analysis, and wetting angle measurement were performed. Statistically significant changes were found between some of the groups in the fractal dimension analysis. In texture analysis, all but one intergroup comparison showed statistically significant differences. For wetting angle assessment, statistically significant differences were found. These were, however, more numerous when assessing glycol droplets, rather than water droplets. Fractal dimension analysis confirmed a correlation between the intensity of changes in the aligner surface with immersion time in the liquids assessed. Texture analysis showed a high sensitivity to the changes in aligner surface. It failed, however, to reveal changes relative to immersion time. Wetting angle analysis revealed aligner surface degradation for Coca-Cola. It did not, however, prove the dependence of the intensity of this degradation as a function of time. Both Coca-Cola and orange juice can cause aligner surface degradation.
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Affiliation(s)
- Maciej Warnecki
- Independent Researcher, Niemodlińska 63, 45-864 Opole, Poland
| | - Michał Sarul
- Department of Integrated Dentistry, Wrocław Medical University, 50-425 Wrocław, Poland
| | - Marcin Kozakiewicz
- Department of Maxillofacial Surgery, Medical University of Lodz, 113 Żeromskiego Str., 90-549 Lodz, Poland
| | - Anna Zięty
- Department of Mechanics, Materials and Biomedical Engineering, Faculty of Mechanical Engineering, Wrocław University of Science and Technology, Smoluchowskiego 25, 50-372 Wrocław, Poland
| | - Bartosz Babiarczuk
- Department of Mechanics, Materials and Biomedical Engineering, Faculty of Mechanical Engineering, Wrocław University of Science and Technology, Smoluchowskiego 25, 50-372 Wrocław, Poland
| | - Beata Kawala
- Department of Dentofacial Orthopedics and Orthodontics, Wrocław Medical University, Krakowska 26, 50-425 Wrocław, Poland
| | - Kamil Jurczyszyn
- Department of Oral Surgery, Wrocław Medical University, Krakowska 26, 50-425 Wrocław, Poland
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Ammann R, Tanner C, Schulz G, Osmani B, Nalabothu P, Töpper T, Müller B. Three-dimensional analysis of aligner gaps and thickness distributions, using hard x-ray tomography with micrometer resolution. J Med Imaging (Bellingham) 2022; 9:031509. [PMID: 36267352 PMCID: PMC9574087 DOI: 10.1117/1.jmi.9.3.031509] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 05/31/2022] [Indexed: 07/02/2024] Open
Abstract
PURPOSE The morphology of a polymer aligner, designed according to an orthodontic treatment plan, determines clinical outcomes. A fundamental element of orthodontic tooth movement with aligner treatment is the fit of the aligner's surface to the individual teeth. Gaps between the aligner and teeth do occur because current aligner fabrication is not capable of completely reproducing the complex anatomy of the individual denture. Our study aims at a quantitative three-dimensional assessment of the fit between optically transparent aligners placed on a polymeric model of the upper dental arch for two thermofoil thicknesses at preselected thermoforming temperatures. APPROACH Using an intraoral scan of a subject's upper dental arch, eight models were printed using a stereolithographic system. A series of eight NaturAligners® was manufactured with a pressure molding process, using thermofoils with thicknesses of 550 and 750 μ m and preselected process temperatures between 110°C and 210°C. These aligners placed on the corresponding models were imaged by an advanced micro computed tomography system. The aligners and the models were segmented to extract the gaps and aligners' local thicknesses as a function of the processing temperature for the two foil thicknesses. RESULTS The results indicate that the aligners show a better fit when the foils are processed at higher temperatures. Nevertheless, processing temperatures can be kept below 150°C, as the gain becomes negligible. Thermal processing reduces the average thickness of the aligners to 60% with respect to the planar starting foil. These thickness distributions demonstrate that the aligners are generally thicker on the occlusal surfaces of molars and premolars but thinner around the incisors and buccal as well as on oral surfaces. CONCLUSIONS Hard x-ray tomography with micrometer resolution is a powerful technique employed to localize the gaps between aligners and teeth, and it also enables film thickness measurements after thermoforming. The thicker film on the occlusal surfaces is most welcome because of aligner abrasion during wear. The NaturAligner® surfaces consist of a 25 - μ m -thin cellulose layer, and thus the microplastics released via abrasion of less than this thickness are expected to be substantially less critical than for other commercially available, optically transparent aligners.
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Affiliation(s)
- Rémi Ammann
- University of Basel, Biomaterials Science Center, Department of Biomedical Engineering, Allschwil, Switzerland
- University of Basel, Biomaterials Science Center, Department of Clinical Research, Basel, Switzerland
| | - Christine Tanner
- University of Basel, Biomaterials Science Center, Department of Biomedical Engineering, Allschwil, Switzerland
- University of Basel, Biomaterials Science Center, Department of Clinical Research, Basel, Switzerland
| | - Georg Schulz
- University of Basel, Biomaterials Science Center, Department of Biomedical Engineering, Allschwil, Switzerland
- University of Basel, Core Facility Micro- and Nanotomography, Department of Biomedical Engineering, Allschwil, Switzerland
| | - Bekim Osmani
- University of Basel, Biomaterials Science Center, Department of Biomedical Engineering, Allschwil, Switzerland
- University of Basel, Biomaterials Science Center, Department of Clinical Research, Basel, Switzerland
| | - Prasad Nalabothu
- University Hospital Basel, Department of Oral and Craniomaxillofacial Surgery, Basel, Switzerland
- University of Basel, Center for Dental Medicine, Department of Pediatric Oral Health and Orthodontics, Basel, Switzerland
| | - Tino Töpper
- University of Basel, Biomaterials Science Center, Department of Biomedical Engineering, Allschwil, Switzerland
- University of Basel, Biomaterials Science Center, Department of Clinical Research, Basel, Switzerland
| | - Bert Müller
- University of Basel, Biomaterials Science Center, Department of Biomedical Engineering, Allschwil, Switzerland
- University of Basel, Biomaterials Science Center, Department of Clinical Research, Basel, Switzerland
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16
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Koenig N, Choi JY, McCray J, Hayes A, Schneider P, Kim KB. Comparison of dimensional accuracy between direct-printed and thermoformed aligners. Korean J Orthod 2022; 52:249-257. [PMID: 35466087 PMCID: PMC9314211 DOI: 10.4041/kjod21.269] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 11/19/2022] Open
Abstract
Objective The purpose of this study was to evaluate and compare the dimensional accuracy between thermoformed and direct-printed aligners. Methods Three types of aligners were manufactured from the same reference standard tessellation language (STL) file thermoformed aligners were manufactured using Zendura FLXTM (n = 12) and Essix ACETM (n = 12), and direct-printed aligners were printed using Tera HarzTM TC-85DAP 3D Printer UV Resin (n = 12). The teeth were not manipulated with any tooth-moving software in this study. The samples were sprayed with an opaque scanning spray, scanned, imported to Geomagic® Control XTM metrology software, and superimposed on the reference STL file by using the best-fit alignment algorithm. Distances between the aligner meshes and the reference STL file were measured at nine anatomical landmarks. Results Mean absolute discrepancies in the Zendura FLXTM aligners ranged from 0.076 ± 0.057 mm to 0.260 ± 0.089 mm and those in the Essix ACETM aligners ranged from 0.188 ± 0.271 mm to 0.457 ± 0.350 mm, while in the direct-printed aligners, they ranged from 0.079 ± 0.054 mm to 0.224 ± 0.041 mm. Root mean square values, representing the overall trueness, ranged from 0.209 ± 0.094 mm for Essix ACETM, 0.188 ± 0.074 mm for Zendura FLXTM, and 0.140 ± 0.020 mm for the direct-printed aligners. Conclusions This study showed greater trueness and precision of direct-printed aligners than thermoformed aligners.
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Affiliation(s)
- Nickolas Koenig
- Department of Orthodontics, Saint Louis University, Saint Louis, MO, USA
| | - Jin-Young Choi
- Department of Orthodontics, Graduate School of Dentistry, Kyung Hee University, Seoul, Korea
| | - Julie McCray
- Department of Orthodontics, Saint Louis University, Saint Louis, MO, USA
| | - Andrew Hayes
- Department of Orthodontics, Saint Louis University, Saint Louis, MO, USA
| | - Patricia Schneider
- Department of Orthodontics, Saint Louis University, Saint Louis, MO, USA
| | - Ki Beom Kim
- Department of Orthodontics, Saint Louis University, Saint Louis, MO, USA
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ERGEL D, SADRY S, OK U. Ortodontide Kullanılan Şeffaf Plakların Su Emilimlerinin ve Renklenmelerinin Değerlendirmesi. İSTANBUL GELIŞIM ÜNIVERSITESI SAĞLIK BILIMLERI DERGISI 2021. [DOI: 10.38079/igusabder.1010796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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18
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Pratto I, Busato MCA, Bittencourt PRS. Thermal and mechanical characterization of thermoplastic orthodontic aligners discs after molding process. J Mech Behav Biomed Mater 2021; 126:104991. [PMID: 34864573 DOI: 10.1016/j.jmbbm.2021.104991] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 11/17/2021] [Accepted: 11/18/2021] [Indexed: 10/19/2022]
Abstract
Polymeric aesthetic aligners were introduced in orthodontics as an innovative alternative to fixed appliances, however, their compositions and the thermal molding process may influence the biomechanical characteristics of these aligners. In this study four different clear aligner brands were used, ACE 035 Essix, C + Essix, Crystal 0.75 and Crystal 1.0, whose aim was to identify the thermal-processing influence on the mechanical and physicochemical properties of these materials, and to suggest a orthodontic sequence of wear for these appliances to achieve more effective treatment results. For the tensile tests the sample size calculation was based on probability distributions from the F test. The effect size used was 0.3, type 1 error of 0.05. Statistical Yield strength and Young's Modulus results were evaluated using the Shapiro-Wilk test. The groups were compared using the parametric test of analysis of variance, with Tukey post-test. Differences were statistically considered at the p < 0.05. The Infrared spectroscopy analysis showed no changes in the samples' chemical structure after thermal-processing. However, in the polypropylene aligner, differences were verified in the region attributed to the crystalline phase. Differential Scanning Calorimetry analysis for the same sample showed a crystallinity fraction decrease due to relaxation between polymer chains after molding. In the tensile tests evaluated, the tensile strength and 'Young's modulus presented higher values for aligners containing 100% polyethylene terephthalate glycol. Performing an analogy exercise of the properties of orthodontic wires used in conventional fixed appliances and, relating them to orthodontic plastics, aligners composed of different materials and/or thicknesses could be used in increasing sequence in terms of the modulus of elasticity, starting with C+, which has a lower elastic modulus value, using the ACE 035 as an intermediate and finishing with the Crystal 0.75 and 1.0, providing the desired stiffness to the aligners for the final phase.
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Affiliation(s)
- Isabella Pratto
- Universidade Estadual do Oeste do Paraná (UNIOESTE), Departamento de Odontologia, ZIP 85819-110, Cascavel, Paraná, Brazil
| | - Mauro Carlos Agner Busato
- Universidade Estadual do Oeste do Paraná (UNIOESTE), Departamento de Odontologia, ZIP 85819-110, Cascavel, Paraná, Brazil
| | - Paulo Rodrigo Stival Bittencourt
- Universidade Tecnológica Federal do Paraná (UTFPR), Departamento Acadêmico de Química, Bloco I4, ZIP 85884-000, Medianeira, Paraná, Brazil.
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Xiang N, Zhang X, Zheng M, Xu R, Yan Y. Investigation of tensile behavior and molecular structure of the thermoplastic polyurethane sheets injection molded at different mold temperatures. J Appl Polym Sci 2021. [DOI: 10.1002/app.50959] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Ning Xiang
- Beijing Institute of Aeronautical Materials AECC, Beijing Engineering Research Centre of Advanced Structural Transparencies for the Modern Traffic System Beijing China
| | - Xiaowen Zhang
- Beijing Institute of Aeronautical Materials AECC, Beijing Engineering Research Centre of Advanced Structural Transparencies for the Modern Traffic System Beijing China
| | - Mengyao Zheng
- Beijing Institute of Aeronautical Materials AECC, Beijing Engineering Research Centre of Advanced Structural Transparencies for the Modern Traffic System Beijing China
| | - Ruijie Xu
- Guangdong Provincial Key Laboratory of Functional Soft Condensed Matter, Guangdong Provincial Engineering Laboratory of Energy Storage Materials and Devices, School of Materials and Energy Guangdong University of Technology Guangzhou China
| | - Yue Yan
- Beijing Institute of Aeronautical Materials AECC, Beijing Engineering Research Centre of Advanced Structural Transparencies for the Modern Traffic System Beijing China
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20
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Palone M, Longo M, Arveda N, Nacucchi M, Pascalis FD, Spedicato GA, Siciliani G, Lombardo L. Micro-computed tomography evaluation of general trends in aligner thickness and gap width after thermoforming procedures involving six commercial clear aligners: An in vitro study. Korean J Orthod 2021; 51:135-141. [PMID: 33678629 PMCID: PMC7940810 DOI: 10.4041/kjod.2021.51.2.135] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 11/28/2020] [Accepted: 12/09/2020] [Indexed: 11/10/2022] Open
Abstract
Objective To assess the effects of thermoforming on aligner thickness and gap width in six aligner systems with the same nominal thickness. Methods Six passive upper aligners of different brands were adapted to a single printed cast. Each sample was evaluated with high-resolution micro-computed tomography. To investigate aligner thickness and gap width, two-dimensional (2D) analysis was conducted assessing the effects of the following variables tooth type (central incisor, canine, and first molar), 2D reference points, and aligner type. Data were analyzed and compared using analysis of variance and Tukey’s post-hoc tests (p < 0.05). Results Tooth type, dental region, and aligner type affected both the gap width and aligner thickness. The aligner thickness remained moderately stable across the arch only in the F22. Conclusions All thermoformed samples displayed smaller aligner thickness and gap width at anterior teeth and both gingival and coronal centers than at posterior teeth and occlusal surfaces.
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Affiliation(s)
- Mario Palone
- Postgraduate School of Orthodontics, University of Ferrara, Ferrara, Italy
| | - Mattia Longo
- Postgraduate School of Orthodontics, University of Ferrara, Ferrara, Italy
| | - Niki Arveda
- Postgraduate School of Orthodontics, University of Ferrara, Ferrara, Italy
| | - Michele Nacucchi
- Division for Sustainable Materials, Research Centre of Brindisi, Brindisi, Italy
| | - Fabio De Pascalis
- Division for Sustainable Materials, Research Centre of Brindisi, Brindisi, Italy
| | | | - Giuseppe Siciliani
- Department of Translational Medicine and for Romagna, School of Dentistry, University of Ferrara, Ferrara, Italy
| | - Luca Lombardo
- Postgraduate School of Orthodontics, University of Ferrara, Ferrara, Italy
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21
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Putrino A, Barbato E, Galluccio G. Clear Aligners: Between Evolution and Efficiency-A Scoping Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18062870. [PMID: 33799682 PMCID: PMC7998651 DOI: 10.3390/ijerph18062870] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 02/18/2021] [Accepted: 03/02/2021] [Indexed: 12/21/2022]
Abstract
In recent years, clear aligners have diversified and evolved in their primary characteristics (material, gingival margin design, attachments, divots, auxiliaries), increasing their indications and efficiency. We overviewed the brands of aligners used in Italy and reviewed the literature on the evolution of clear aligners based on their characteristics mentioned above by consulting the main scientific databases (PubMed, Scopus, Lilacs, Google Scholar, Cochrane Library). Inclusion and exclusion criteria were established. The data were collected on a purpose-made data collection form and analyzed descriptively. From the initial 580 records, 527 were excluded because they were not related to the subject of the review or because they did not meet the eligibility criteria. The remaining 31 studies were deemed comprehensive for the purpose of the review, although the “gingival margin design” feature and “auxiliaries” tool are not well represented in the more recent literature. Current knowledge on invisible aligners allows us to have a much clearer idea of the basic characteristics of aligner systems. There remains a need to deepen the use of systems other than Invisalign™ to give greater evidence to aligners that are very different based on the characteristics analyzed here and that are very widespread on the market.
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ATR-FTIR Analysis of Orthodontic Invisalign ® Aligners Subjected to Various In Vitro Aging Treatments. MATERIALS 2021; 14:ma14040818. [PMID: 33572096 PMCID: PMC7914755 DOI: 10.3390/ma14040818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 02/03/2021] [Accepted: 02/04/2021] [Indexed: 11/16/2022]
Abstract
Clear and removable tooth aligners for orthodontics treatments have become an increasingly popular alternative to fixed appliances. Even if protocols suggest removing aligners before eating or drinking, most patients retain them when they drink beverages. Alterations in the material during the daily use could determine a reduction in the application forces, affecting the desired orthodontic movement; the knowledge of how this material reacts when subjected to different aging processes is mandatory to establish the predictability of the orthodontic treatment. According to this, the aim of the present study was to assess a new objective approach, coupling spectroscopic and chemometric tools, to evaluate the changes occurring in Invisalign® aligners, the most widely used brand, exposed in vitro to coffee, tea, Coca Cola® and UV radiation for 24 and 48 h. In particular, ATR-FTIR spectroscopy was utilized to characterize, at the molecular level, the chemical and color modifications in the surfaces of the appliances; the obtained data were submitted to PCA and one-way ANOVA and Tukey's multiple comparison test. Moreover, a colorimetry analysis was carried out to evaluate any changes in color and transparency. Coffee and tea samples displayed the major color changes between the tested groups. The differences highlighted in the spectral features of coffee, tea and UV-treated samples were mainly ascribable to color and transparency changes, because the chemical properties remained unaltered.
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Yaosen C, Mohamed AM, Jinbo W, Ziwei Z, Al-balaa M, Yan Y. Risk Factors of Composite Attachment Loss in Orthodontic Patients during Orthodontic Clear Aligner Therapy: A Prospective Study. BIOMED RESEARCH INTERNATIONAL 2021; 2021:6620377. [PMID: 33553424 PMCID: PMC7847320 DOI: 10.1155/2021/6620377] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Revised: 01/16/2021] [Accepted: 01/20/2021] [Indexed: 12/15/2022]
Abstract
BACKGROUND The composite attachment loss during orthodontic clear aligner therapy is an adverse event that commonly happens in our daily practice. However, there is a lack of related statistical analysis and studies analyzing the related risk factors. Therefore, the aim of this study is to assess the incidence of attachment loss during orthodontic clear aligner therapy and to identify rick factors that may predict such event. MATERIALS AND METHODS The demographics and clinical variables of 94 patients undergoing clear aligner therapy (27 males and 67 females; average age: 27.60 ± 0.86 years) were recorded. Both patient-related and tooth-related attachment loss was recorded. The chi-squared test and logistic regressive analysis were applied to identify the potential risk factors. SPSS for Mac (version 23.0, IBM, USA) was used for statistical analyses. P < 0.05 was considered statistically significant. RESULTS Our study suggested that the risk factors for attachment loss include frequent aligner removal (≥ 5 times a day) (losing rate = 60.0%, P = 0.005), aligner wear time less than 18 hours a day (losing rate = 50.8%, P = 0.014), eating without aligners inserted (losing rate = 47.9%, P = 0.034), utilizing aligner tray seaters (losing rate = 48.2%, P = 0.006), and unilateral mastication (losing rate = 52.1%, P = 0.002). The multivariable logistic regression analysis indicates that aligner wear time less than 18 hours a day (P = 0.020, B = 0.925), using aligner tray seaters (P = 0.007, B = 1.168), and unilateral mastication (P = 0.034, B = -0.458) were considered independent factors that can predict the composite attachment loss in orthodontic clear aligner therapy. CONCLUSION Wearing aligner less than 18 hours a day, using aligner tray seaters, and unilateral mastication may contribute to increased incidence of composite attachment loss during orthodontic clear aligner therapy.
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Affiliation(s)
- Chen Yaosen
- MDS Orthodontic Section of Stomatology Department, Zhongnan Hospital, Wuhan University, Wuhan, China 430000
| | - A. M. Mohamed
- MDS Orthodontic Section of Stomatology Department, Zhongnan Hospital, Wuhan University, Wuhan, China 430000
| | - Wang Jinbo
- Master of Nursing Department, Zhongnan Hospital, Wuhan University, Wuhan, China 430000
| | - Zheng Ziwei
- College of Stomatology, Hubei University of Science and Technology, Xianning, China 437000
| | - Maher Al-balaa
- MDS Orthodontic Section of School of Stomatology, Wuhan University, Wuhan, China 430000
| | - Yang Yan
- Stomatology Department, Zhongnan Hospital, Wuhan University, Wuhan, Hubei 430000, China
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Behaviour of Human Oral Epithelial Cells Grown on Invisalign ® SmartTrack ® Material. MATERIALS 2020; 13:ma13235311. [PMID: 33255259 PMCID: PMC7727678 DOI: 10.3390/ma13235311] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 11/13/2020] [Accepted: 11/15/2020] [Indexed: 11/18/2022]
Abstract
Invisalign aligners have been widely used to correct malocclusions, but their effect on oral cells is poorly known. Previous research evaluated the impact of aligners’ eluates on various cells, but the cell behavior in direct contact with aligners is not yet studied. In the present study, we seeded oral epithelial cells (cell line Ca9-22) directly on Invisalign SmartTrack material. This material is composed of polyurethane and co-polyester and exhibit better mechanical characteristics compared to the predecessor. Cell morphology and behavior were investigated by scanning electron microscopy and an optical cell moves analyzer. The effect of aligners on cell proliferation/viability was assessed by cell-counting kit (CCK)-8 and 3,4,5-dimethylthiazol-2-yl-2,5-diphenyl tetrazolium bromide (MTT) assay and live/dead staining. The expression of inflammatory markers and proteins involved in epithelial barrier function was measured by qPCR. Cells formed cluster-like structures on aligners. The proliferation/viability of cells growing on aligners was significantly lower (p < 0.05) compared to those growing on tissue culture plastic (TCP). Live/dead staining revealed a rare occurrence of dead cells on aligners. The gene expression level of all inflammatory markers in cells grown on aligners’ surfaces was significantly increased (p < 0.05) compared to cells grown on TCP after two days. Gene expression levels of the proteins involved in barrier function significantly increased (p < 0.05) on aligners’ surfaces after two and seven days of culture. Aligners’ material exhibits no cytotoxic effect on oral epithelial cells, but alters their behavior and the expression of proteins involved in the inflammatory response, and barrier function. The clinical relevance of these effects has still to be established.
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Lombardo L, Palone M, Carlucci A, Siciliani G. Clear aligner hybrid approach: A case report. J World Fed Orthod 2020; 9:32-43. [PMID: 32672666 DOI: 10.1016/j.ejwf.2020.01.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Revised: 12/31/2019] [Accepted: 01/02/2020] [Indexed: 11/16/2022]
Abstract
INTRODUCTION This case demonstrates that hybrid application of clear aligners can be a rational and efficient approach for treating malocclusions, as compared with a clear aligner therapy alone option in which the magnitude of some movements would require a higher number of aligners and likely further refinement. TREATMENT PLAN AND PROGRESS After a first successful orthopedic phase face mask + rapid maxillary expansion (FM + RME), a diagnostic digital setup of the second orthodontic treatment phase was performed, opting for an esthetic approach to make the treatment as fast and efficient as possible. After positioning lingual tubes on both arches, digital models were obtained and lingual archwires, passing through the previously positioned tubes, were simulated digitally. Then, a virtual setup comprising 10 steps for both arches was planned. Aligners enveloped fixed partial lingual appliances, improving patient comfort and efficiency of overall treatment. Aligners were changed every 7 days and the second phase of treatment was finished in 10 weeks with good occlusion and alignment in both arches. The entire treatment of the Class III patient was completed in 13 months of active therapy. CONCLUSION Combining clear aligner therapy and fixed lingual appliance is an esthetic means of treating malocclusions in a shorter treatment time with low costs and high efficiency.
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Affiliation(s)
- Luca Lombardo
- Department of Orthodontics, University of Ferrara, Ferrara, Italy
| | - Mario Palone
- Department of Orthodontics, University of Ferrara, Ferrara, Italy.
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Lombardo L, Palone M, Longo M, Arveda N, Nacucchi M, De Pascalis F, Spedicato GA, Siciliani G. MicroCT X-ray comparison of aligner gap and thickness of six brands of aligners: an in-vitro study. Prog Orthod 2020; 21:12. [PMID: 32390068 PMCID: PMC7211786 DOI: 10.1186/s40510-020-00312-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 04/08/2020] [Indexed: 11/10/2022] Open
Abstract
Background To investigate and compare the gap (i.e. fit) and thickness of six aligner systems (Airnivol, ALL IN, Arc Angel, F22, Invisalign and Nuvola) using industrial computed tomography (CT). The null hypothesis was that there would be no detectable differences in either measurement between the aligners investigated. Materials and methods Passive aligners of each brand were fitted to one single resin cast prototyped from an STL file from a single patient. The samples obtained were examined under high-resolution micro-CT, and the resulting tomographic microphotographs and volumetric data were compared. 3D analysis investigated the gap volume, the mean gap width and the maximum gap width of each sample. A total of 204 linear 2D measurements were made on 18 microtomographic images to investigate the aligner gap and thickness among different systems. Investigated regions were the central incisor, canine and first molar. The resulting measurements were analysed by ANOVA and compared using Tukey’s post hoc analysis (P < 0.05). Results 3D analysis revealed that the F22 displayed lower gap volume and mean gap width, followed by Airnivol and Invisalign, whereas Airnivol the lowest maximum gap width. 2D analysis showed that F22 had the lowest mean gap and aligner thickness at all teeth investigated. Comparison of the 2D point values revealed statistically significant differences between brands in terms of both measurements (P < 0.05), with the exception of six points in the gap analysis and one in the thickness analysis. Conclusions There are differences between the six aligner systems examined in terms of 2D and 3D measurements of aligner thickness and gap.
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Affiliation(s)
- Luca Lombardo
- Postgraduate School of Orthodontics, University of Ferrara, Via Luigi Borsari 46, 44121, Ferrara, Italy
| | - Mario Palone
- Postgraduate School of Orthodontics, University of Ferrara, Via Luigi Borsari 46, 44121, Ferrara, Italy.
| | - Mattia Longo
- Postgraduate School of Orthodontics, University of Ferrara, Via Luigi Borsari 46, 44121, Ferrara, Italy
| | - Niki Arveda
- Postgraduate School of Orthodontics, University of Ferrara, Via Luigi Borsari 46, 44121, Ferrara, Italy
| | - Michele Nacucchi
- Division for Sustainable Materials, Research Centre of Brindisi, S.S. 7 Appia km 706,00, I-72100, Brindisi, Italy
| | - Fabio De Pascalis
- Division for Sustainable Materials, Research Centre of Brindisi, S.S. 7 Appia km 706,00, I-72100, Brindisi, Italy
| | | | - Giuseppe Siciliani
- Postgraduate School of Orthodontics, University of Ferrara, Via Luigi Borsari 46, 44121, Ferrara, Italy
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Bernard G, Rompré P, Tavares JR, Montpetit A. Colorimetric and spectrophotometric measurements of orthodontic thermoplastic aligners exposed to various staining sources and cleaning methods. Head Face Med 2020; 16:2. [PMID: 32070379 PMCID: PMC7027305 DOI: 10.1186/s13005-020-00218-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 02/12/2020] [Indexed: 11/25/2022] Open
Abstract
Background Manufacturers of orthodontic aligners suggest that users remove appliances every time they consume solid foods or any drink (except water). This is to avoid a color change within the clear thermoplastic material of which they are made. However, limited quantitative evidence exists to guide users and practitioners in this regard. Herein, we evaluated the color stability of the polymer forming three different American brands of aligners and the stain-removal potential of two cleansers to provide such guidelines. Methods The removable appliances (300 specimens, 100 per brand) were exposed to different staining agents common in a regular diet (coffee, black tea, red wine, cola) or to a control solution in vitro over 12 h or 7 days. The three brands evaluated were Invisalign®, ClearCorrect® and Minor Tooth Movement®. These were then cleaned by using either Invisalign® cleaning crystals or the Cordless Sonic Cleaner combined with a Retainer Brite® tablet. The CIELAB color space approach was used to compare color changes (ΔE) in aligners before immersion (T0), after a 12-h exposure (T1), after a 7-day exposure (T2) and after cleaning (T3). Statistical methods (Levene’s test, ANOVA, Brunner-Langer model, Tukey’s range test and t-test) were used to identify interactions between the brands themselves or between the brands and the cleaning methods. Statistical analyses were performed at the .05 significance level. Results A 12-h or 7-day exposure to instant coffee or red wine significantly colored the Invisalign® aligners compared to the two other brands. Black tea created an important extrinsic color change for all three brands after 7 days. Clinically, both cleaning methods showed a better efficacy in removing stains from black tea compared to other staining agents. Conclusions The Invisalign® aligners were more prone to pigmentation than the ClearCorrect® or the Minor Tooth Movement® devices after an exposure to coffee or red wine. Black tea caused important stains on the surface of the three tested brands. Both cleansing methods performed similarly.
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Affiliation(s)
- Gabrielle Bernard
- Department of Oral Health - Orthodontics Section, Faculty of Dental Medicine, Université de Montréal, Québec, Canada
| | - Pierre Rompré
- Department of Oral Health - Orthodontics Section, Faculty of Dental Medicine, Université de Montréal, Québec, Canada
| | - Jason Robert Tavares
- CREPEC, Department of Chemical Engineering, Polytechnique Montréal, P.O. Box 6079, Stat. Centre-Ville, Montréal, Québec, H3C 3A7, Canada.
| | - Andrée Montpetit
- Department of Oral Health - Orthodontics Section, Faculty of Dental Medicine, Université de Montréal, Québec, Canada
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Xiang N, Zhang X, Zheng M, Ge Y, Wang T, Liu H, Maharaj C, Dear JP, Yan Y. Microstructure and tensile properties of injection molded thermoplastic polyurethane with different melt temperatures. J Appl Polym Sci 2020. [DOI: 10.1002/app.48891] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Ning Xiang
- Beijing Institute of Aeronautical Materials, AECCBeijing Engineering Research Centre of Advanced Structural Transparencies for the Modern Traffic System Beijing 100095 China
| | - Xiaowen Zhang
- Beijing Institute of Aeronautical Materials, AECCBeijing Engineering Research Centre of Advanced Structural Transparencies for the Modern Traffic System Beijing 100095 China
| | - Mengyao Zheng
- Beijing Institute of Aeronautical Materials, AECCBeijing Engineering Research Centre of Advanced Structural Transparencies for the Modern Traffic System Beijing 100095 China
| | - Yong Ge
- Beijing Institute of Aeronautical Materials, AECCBeijing Engineering Research Centre of Advanced Structural Transparencies for the Modern Traffic System Beijing 100095 China
| | - Tao Wang
- Beijing Institute of Aeronautical Materials, AECCBeijing Engineering Research Centre of Advanced Structural Transparencies for the Modern Traffic System Beijing 100095 China
| | - Haibao Liu
- Department of Mechanical EngineeringImperial College London London SW7 2AZ United Kingdom
| | - Chris Maharaj
- Department of Mechanical and Manufacturing EngineeringThe University of the West Indies St. Augustine Trinidad and Tobago
| | - John P. Dear
- Department of Mechanical EngineeringImperial College London London SW7 2AZ United Kingdom
| | - Yue Yan
- Beijing Institute of Aeronautical Materials, AECCBeijing Engineering Research Centre of Advanced Structural Transparencies for the Modern Traffic System Beijing 100095 China
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Bucci R, Rongo R, Levatè C, Michelotti A, Barone S, Razionale AV, D'Antò V. Thickness of orthodontic clear aligners after thermoforming and after 10 days of intraoral exposure: a prospective clinical study. Prog Orthod 2019; 20:36. [PMID: 31495908 PMCID: PMC6732265 DOI: 10.1186/s40510-019-0289-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 08/06/2019] [Indexed: 12/18/2022] Open
Abstract
Background Clear aligners (CA) are among the most chosen orthodontic therapies for patients who require an invisible treatment. Previous studies showed that the thermoforming process and the complexity of the intraoral environment might alter the properties of these devices. The aim of the current prospective clinical study was to assess the thickness changes of the CA after 10 days of intraoral use. The secondary aim was to assess the reproducibility of the thermoforming process, in terms of aligner thickness. Materials and methods CA from 18 consecutive patients (13 women, 5 men, mean age 28.8 ± 9.6 years) were investigated. Before intraoral exposure (T0), the thickness of the unused CA was measured at different occlusal points on a 3D model with a dedicated software (Geomagic Qualify 2013; 3D Systems, Rock Hill, SC, USA). Two CA configurations were studied: passive maxillary aligner (P—no tooth movement; no shape for attachments) and active maxillary aligner (A—tooth movement; shape for attachments and divot). The used aligners were returned after 10 days (T1) and the thickness measurements were repeated. A Student’s t test for paired data (T1 vs. T0) was applied to compare the thicknesses of used and unused devices (significance level after Bonferroni correction for multiple comparison was set at p < 0.0014). Furthermore, to study the reproducibility of the thermoforming process, P and A aligners were thermoformed twice, and the thicknesses of the two unused thermoformed devices were compared by means of Student’s t test for paired data (significance level after Bonferroni correction for multiple comparison was set at p < 0.0014) and Dahlberg’s error. Results The thermoforming process showed good reproducibility for both aligner configurations, with a maximum Dahlberg’s error of 0.13 mm. After intraoral use, the thickness of P showed some statistically significant, but not clinically relevant, thickness changes as compared to the unused aligners, while A did not show any significant changes. Conclusion Considering the thickness changes, the thermoforming process is reliable both with active and passive aligner configurations. Also, the CA examined show good thickness stability after physiological intraoral ageing in a population of healthy adults.
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Affiliation(s)
- Rosaria Bucci
- Department of Neurosciences, Reproductive Sciences and Oral Sciences, University of Naples Federico II, via Pansini 5, 80131, Naples, Italy
| | - Roberto Rongo
- Department of Neurosciences, Reproductive Sciences and Oral Sciences, University of Naples Federico II, via Pansini 5, 80131, Naples, Italy
| | - Carmine Levatè
- Department of Neurosciences, Reproductive Sciences and Oral Sciences, University of Naples Federico II, via Pansini 5, 80131, Naples, Italy
| | - Ambrosina Michelotti
- Department of Neurosciences, Reproductive Sciences and Oral Sciences, University of Naples Federico II, via Pansini 5, 80131, Naples, Italy
| | - Sandro Barone
- Department of Civil and Industrial Engineering, University of Pisa, Largo Lucio Lazzarino 1, 56122, Pisa, Italy
| | - Armando Viviano Razionale
- Department of Civil and Industrial Engineering, University of Pisa, Largo Lucio Lazzarino 1, 56122, Pisa, Italy
| | - Vincenzo D'Antò
- Department of Neurosciences, Reproductive Sciences and Oral Sciences, University of Naples Federico II, via Pansini 5, 80131, Naples, Italy.
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Papadopoulou AK, Cantele A, Polychronis G, Zinelis S, Eliades T. Changes in Roughness and Mechanical Properties of Invisalign ® Appliances after One- and Two-Weeks Use. MATERIALS 2019; 12:ma12152406. [PMID: 31357697 PMCID: PMC6696190 DOI: 10.3390/ma12152406] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 07/23/2019] [Accepted: 07/26/2019] [Indexed: 11/25/2022]
Abstract
The aim of this study was to estimate the possible changes of surface roughness and the mechanical properties of Invisalign® appliances over one- and two-week of service. Forty appliances with attachments were retrieved after the end of orthodontic treatment from different patients. Half of them had been used for one week (1W), and the rest for two weeks (2W). Ten unused Invisalign® appliances were used as the control (CON). An equal number of teeth possessing attachments were cut of aligners deriving from all groups (1W, 2W, and CON), and the Sa, Sq, Sz, Sc, and Sv roughness parameters of the internal surface of the aligner attachment area and the opposite lingual side (which was in contact to enamel) were determined by optical profilometry. Then, ten first molars originating from all groups were embedded in acrylic resin, and were ground and polished. Instrumented indentation testing (IIT) was performed in order to determine the Martens hardness (HM), indentation modulus (EIT), and relaxation index (RIT), according to ISO 14577-2002. The produced data were statistically processed by one- or two-way analysis of variance (ANOVA) and multiple comparison post-hoc tests (a = 0.05). Both the surface roughness and mechanical properties of the retrieved groups (1W and 2W) showed statistically significant differences compared with CON, but without statistically significant differences between each other. The roughness variables of the as-received material were shown to be reduced after intraoral service demonstrating a wear effect. Ageing has a detrimental effect on the surface roughness and mechanical properties of Invisalign® appliances, although this effect is restricted to the first week of clinical usage.
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Affiliation(s)
| | - Aurelie Cantele
- Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, 8032 Zurich, Switzerland
| | - Georgios Polychronis
- Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, 11527 Athens, Greece
| | - Spiros Zinelis
- Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, 11527 Athens, Greece
| | - Theodore Eliades
- Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, 8032 Zurich, Switzerland.
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Condo' R, Pazzini L, Cerroni L, Pasquantonio G, Lagana' G, Pecora A, Mussi V, Rinaldi A, Mecheri B, Licoccia S, Maiolo L. Mechanical properties of "two generations" of teeth aligners: Change analysis during oral permanence. Dent Mater J 2018; 37:835-842. [PMID: 29998941 DOI: 10.4012/dmj.2017-323] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Aim of this in vitro study was to analyze structural properties of two different polymeric orthodontic aligners, Exceed30 (EX30) and Smart Track (LD30), before and after use. Forty patterns of aligners were randomly selected: 20 LD30 and 20 EX30, worn intra-orally for 14±3 days, 22 h/day. From each aligner, 10 specimens were prepared from buccal surfaces of the incisor region by the cutting of samples 5×5 mm under a stereomicroscope. All samples were subjected to Fourier transform infrared spectroscopy, micro-Raman spectroscopy, X-ray diffraction, tensile and indentation strength test. LD30 appeared more homogeneous, with a crystalline fraction lower than EX30 and exhibited a higher elastic behavior and a lower tendency to warp after use than EX30. LD30 demonstrated better adaptability to the dental arch and greater consistency of application of orthodontic forces than produced with EX30. However, both materials showed structural modifications that resulted in increased sample hardness and hyper-plasticity.
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Affiliation(s)
- Roberta Condo'
- Department of Clinical Sciences and Translational Medicine, University of Rome "Tor Vergata", Via Montpellier
| | - Luca Pazzini
- Institute for Microelectronics and Microsystems -National Research Council (IMM-CNR) Via del Fosso del Cavaliere
| | - Loredana Cerroni
- Department of Clinical Sciences and Translational Medicine, University of Rome "Tor Vergata", Via Montpellier
| | - Guido Pasquantonio
- Department of Clinical Sciences and Translational Medicine, University of Rome "Tor Vergata", Via Montpellier
| | - Giuseppina Lagana'
- Department of Clinical Sciences and Translational Medicine, University of Rome "Tor Vergata", Via Montpellier
| | - Alessandro Pecora
- Institute for Microelectronics and Microsystems -National Research Council (IMM-CNR) Via del Fosso del Cavaliere
| | - Valentina Mussi
- Institute of Complex Systems -National Research Council (ISC-CNR) Via del Fosso del Cavaliere
| | - Antonio Rinaldi
- ENEA -Technical Unit for Material Technologies (UTTMAT) Casaccia Research Center, Via Anguillarese
| | - Barbara Mecheri
- Department of Chemical Science and Technology, University of Rome "Tor Vergata"
| | - Silvia Licoccia
- Department of Chemical Science and Technology, University of Rome "Tor Vergata"
| | - Luca Maiolo
- Institute for Microelectronics and Microsystems -National Research Council (IMM-CNR) Via del Fosso del Cavaliere
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Zafeiriadis AA, Karamouzos A, Athanasiou AE, Eliades T, Palaghias G. An in vivo spectrophotometric evaluation of Vivera® and Essix® clear thermoplastic retainer discolouration. AUSTRALASIAN ORTHODONTIC JOURNAL 2018. [DOI: 10.21307/aoj-2020-053] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Abstract
Aim
To assess the in vivo colour alterations of two different clear thermoplastic retainers.
Methods
Thirty patients were randomly allocated into two Groups (N = 15) following the completion of active orthodontic treatment. Group 1 received Vivera® and Group 2 Essix® C+ thermoplastic retainers. Each patient was provided with two fabricated retainers (one for use and the other to serve as a control). The CIELAB parameters of the patients’ upper central incisors were measured with a SpectroShade™ spectrophotometer immediately after retainer placement (T0) and again after 15 days (T1), one month (T2) and three months (T3). The measurements were also performed on teeth without the retainer in place. ΔE differences were calculated.
Methods
ΔE changes from T0 to Tp T2 or T3 showed no statistically significant differences between Groups 1 and 2 within any combination of measurements or teeth. ΔEļŢ3-Ţ0ļ changes for used retainers were 1.55 times higher than control appliances (p = 0.002) and 1.44 times higher than for teeth-only (p = 0.004). For used retainers, changes between T3 and T0 were 1.56 times higher than between T and T0 and 1.47 higher than between T2 and T0 (p < 0.001). There were no statistically significant differences in ΔE between teeth 11 and 21.
Results
Used retainers exhibited greater colour change than control appliances or teeth-only readings, and increased commensurate with the duration of use. Vivera® and Essix® retainers exhibited similar colour stability. All differences observed were considered clinically acceptable (ΔE < 3.7), although prolonged use could cause clinically significant colour changes.
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Affiliation(s)
- Anastasios A Zafeiriadis
- Department of Orthodontics , Faculty of Dentistry, School of Health Sciences, Aristotle University of Thessaloniki , Thessaloniki , Greece
| | - Andreas Karamouzos
- Department of Orthodontics , Faculty of Dentistry, School of Health Sciences, Aristotle University of Thessaloniki , Thessaloniki , Greece
| | - Athanasios E Athanasiou
- Hamdan Bin Mohammed College of Dental Medicine, Mohammed Bin Rashid University of Medicine and Health Sciences , Dubai , United Arab Emirates
| | - Theodore Eliades
- Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich , Zurich , Switzerland
| | - George Palaghias
- Departments of Basic Dental Sciences and Operative Dentistry, Faculty of Dentistry, School of Health Sciences, Aristotle University of Thessaloniki , Thessaloniki , Greece
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Lombardo L, Arreghini A, Ramina F, Huanca Ghislanzoni LT, Siciliani G. Predictability of orthodontic movement with orthodontic aligners: a retrospective study. Prog Orthod 2017; 18:35. [PMID: 29130127 PMCID: PMC5682257 DOI: 10.1186/s40510-017-0190-0] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 09/18/2017] [Indexed: 11/23/2022] Open
Abstract
Background The aim of this study was to evaluate the predictability of F22 aligners (Sweden & Martina, Due Carrare, Italy) in guiding teeth into the positions planned using digital orthodontic setup. Methods Sixteen adult patients (6 males and 10 females, mean age 28 years 7 months) were selected, and a total of 345 teeth were analysed. Pre-treatment, ideal post-treatment—as planned on digital setup—and real post-treatment models were analysed using VAM software (Vectra, Canfield Scientific, Fairfield, NJ, USA). Prescribed and real rotation, mesiodistal tip and vestibulolingual tip were calculated for each tooth and, subsequently, analysed by tooth type (right and left upper and lower incisors, canines, premolars and molars) to identify the mean error and accuracy of each type of movement achieved with the aligner with respect to those planned using the setup. Results The mean predictability of movements achieved using F22 aligners was 73.6%. Mesiodistal tipping showed the most predictability, at 82.5% with respect to the ideal; this was followed by vestibulolingual tipping (72.9%) and finally rotation (66.8%). In particular, mesiodistal tip on the upper molars and lower premolars were achieved with the most predictability (93.4 and 96.7%, respectively), while rotation on the lower canines was the least efficaciously achieved (54.2%). Conclusions Without the use of auxiliaries, orthodontic aligners are unable to achieve programmed movement with 100% predictability. In particular, although tipping movements were efficaciously achieved, especially at the molars and premolars, rotation of the lower canines was an extremely unpredictable movement.
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Affiliation(s)
- Luca Lombardo
- Postgraduate School of Orthodontics, University of Ferrara, Via Fossato di Mortara, 44100, Ferrara, Italy
| | - Angela Arreghini
- Postgraduate School of Orthodontics, University of Ferrara, Via Fossato di Mortara, 44100, Ferrara, Italy.
| | - Fabio Ramina
- Postgraduate School of Orthodontics, University of Ferrara, Via Fossato di Mortara, 44100, Ferrara, Italy
| | | | - Giuseppe Siciliani
- Postgraduate School of Orthodontics, University of Ferrara, Via Fossato di Mortara, 44100, Ferrara, Italy
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Lombardo L, Martini M, Cervinara F, Spedicato GA, Oliverio T, Siciliani G. Comparative SEM analysis of nine F22 aligner cleaning strategies. Prog Orthod 2017; 18:26. [PMID: 28782094 PMCID: PMC5592163 DOI: 10.1186/s40510-017-0178-9] [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: 04/26/2017] [Accepted: 06/23/2017] [Indexed: 12/04/2022] Open
Abstract
Background The orthodontics industry has paid great attention to the aesthetics of orthodontic appliances, seeking to make them as invisible as possible. There are several advantages to clear aligner systems, including aesthetics, comfort, chairside time reduction, and the fact that they can be removed for meals and oral hygiene procedures. Methods Five patients were each given a series of F22 aligners, each to be worn for 14 days and nights, with the exception of meal and brushing times. Patients were instructed to clean each aligner using a prescribed strategy, and sections of the used aligners were observed under SEM. One grey-scale SEM image was saved per aligner in JPEG format with an 8-bit colour depth, and a total of 45 measurements on the grey scale (“Value” variable) were made. This dataset was analysed statistically via repeated measures ANOVA to determine the effect of each of the nine cleaning strategies in each of the five patients. Results A statistically significant difference in the efficacy of the cleaning strategies was detected. Specifically, rinsing with water alone was significantly less efficacious, and a combination of cationic detergent solution and ultrasonication was significantly more efficacious than the other methods (p < 0.05). Conclusions Of the nine cleaning strategies examined, only that involving 5 min of ultrasonication at 42 k Hz combined with a 0.3% germicidal cationic detergent was observed to be statistically effective at removing the bacterial biofilm from the surface of F22 aligners.
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Affiliation(s)
- Luca Lombardo
- Postgraduate School of Orthodontics, University of Ferrara, Via Montebello 31, Ferrara, 44100, Italy.
| | - Marco Martini
- Postgraduate School of Orthodontics, University of Ferrara, Via Montebello 31, Ferrara, 44100, Italy
| | | | - Giorgio Alfredo Spedicato
- School of Economics, Management and Statistics, University of Bologna, Piazza Scaravilli 2, Bologna, 40121, Italy
| | - Teresa Oliverio
- Postgraduate School of Orthodontics, University of Ferrara, Via Montebello 31, Ferrara, 44100, Italy
| | - Giuseppe Siciliani
- Postgraduate School of Orthodontics, University of Ferrara, Via Montebello 31, Ferrara, 44100, Italy
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ATP Bioluminometers Analysis on the Surfaces of Removable Orthodontic Aligners after the Use of Different Cleaning Methods. Int J Dent 2016; 2016:5926941. [PMID: 27242901 PMCID: PMC4875988 DOI: 10.1155/2016/5926941] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2016] [Accepted: 04/14/2016] [Indexed: 01/14/2023] Open
Abstract
Purpose. The aim was to quantify the bacteria concentration on the surface of orthodontic clear aligners using three different cleaning methods. Furthermore the objective was to validate the efficacy of the bioluminometer in assessing the bacteria concentration. Materials and Methods. Twenty subjects (six males and fourteen females) undergoing orthodontic therapy with clear aligners (Invisalign® Align Technology, Santa Clara, California) were enrolled in this study. The observation time was of six weeks. The patients were instructed to use different cleaning methods (water, brushing with toothpaste, and brushing with toothpaste and use of sodium carbonate and sulphate tablet). At the end of each phase a microbiological analysis was performed using the bioluminometer. Results. The highest bacteria concentration was found on aligners cleaned using only water (583 relative light units); a value of 189 relative light units was found on aligners cleaned with brushing and toothpaste. The lowest bacteria concentration was recorded on aligners cleaned with brushing and toothpaste and the use of sodium carbonate and sulfate tablet. Conclusions. The mechanical removal of the bacterial biofilm proved to be effective with brushing and toothpaste. The best results in terms of bacteria concentration were achieved adding the use of sodium carbonate and sulfate tablet.
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