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Frenkel ES, Mustafa M, Khosravi R, Woloshyn H, Mancl L, Bollen AM. Occlusal contact changes in patients treated with clear aligners: A retrospective evaluation using digital dental models. Am J Orthod Dentofacial Orthop 2024; 165:680-688.e4. [PMID: 38573295 DOI: 10.1016/j.ajodo.2024.01.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 01/01/2024] [Accepted: 01/01/2024] [Indexed: 04/05/2024]
Abstract
INTRODUCTION This study used digital intraoral scans to evaluate how clear aligner treatment affects occlusal contacts and to determine the influence of sex and age on contact changes. Results were compared with contact changes that occur during fixed appliance therapy. METHODS Patients included in this study were treated in a University setting and private practice. Inclusion criteria were a Class I malocclusion treated nonextraction with clear aligners and the presence of pretreatment and posttreatment digital intraoral scans. Scans were imported into specialized software, and occlusal contacts were analyzed. The effects of age and sex on contact changes during clear aligner treatment were determined. Changes in occlusal contacts were compared with changes that occur during nonextraction treatment of patients with a Class I relationship using fixed edgewise appliances. RESULTS A total of 45 clear aligner patients fit the eligibility criteria. Clear aligner treatment reduced the percentage of tight, near, and approximating contacts, whereas the percentage of open and no contacts increased. These changes in occlusal contacts were greater for the older age group studied. Genderinfluenced occlusal contact changes in the anterior dentition only where the decrease in near contacts and increase in open contacts were greater for males. These results for patients treated with clear aligners were similar to those for patients treated with fixed appliances; both treatment modalities reduced close occlusal contacts at the time active treatment was completed. CONCLUSIONS These results indicated that when clear aligners or fixed appliances are used to treat a Class I malocclusion, the resulting occlusion immediately after debonding is not as "tight" as it was at pretreatment.
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Affiliation(s)
- Erica Shapiro Frenkel
- Department of Orthodontics, School of Dentistry, University of Washington, Seattle, Wash.
| | - Mariam Mustafa
- Department of Orthodontics, School of Dentistry, University of Washington, Seattle, Wash
| | - Roozbeh Khosravi
- Department of Orthodontics, School of Dentistry, University of Washington, Seattle, Wash
| | - Heather Woloshyn
- Department of Orthodontics, School of Dentistry, University of Washington, Seattle, Wash
| | - Lloyd Mancl
- Oral Health Sciences, School of Dentistry, University of Washington, Seattle, Wash
| | - Anne-Marie Bollen
- Department of Orthodontics, School of Dentistry, University of Washington, Seattle, Wash
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Hamdi A, Kallala R, Harzallah B. Chewing efficiency and contact area discrepancies in Angle's class I and II malocclusion: A comparative study. Saudi Dent J 2024; 36:633-637. [PMID: 38690385 PMCID: PMC11056408 DOI: 10.1016/j.sdentj.2023.12.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 12/22/2023] [Accepted: 12/25/2023] [Indexed: 05/02/2024] Open
Abstract
Objective The study aimed to assess and compare both the chewing efficiency and the contact area between class I and class II of Angle's malocclusions. Material and methods A total of 120 individuals aged between 19 and 30 years were examined and were divided into two groups according to Angle's class (Class I and class II). The chewing efficiency was quantified using the ViewGum software and two-colored chewing gum. The contact area was quantified using modeling wax and MATLAB software. All data were collected, then, analyzed using SPSS software 21. Data normality was checked through kurtosis test. Descriptive results were calculated. Matched sample t-tests were used to compare chewing efficiency measurements between right and left sides. Independent t-tests were used to compare chewing efficiency and the contact area between class I and class II of Angle's malocclusions. Linear regression and Pearson correlation were used to assess the correlation between chewing efficiency and the contact area. The significance level was fixed at p = 0.05. Results For group 1, the mean hue value on both sides was 0.086 ± 0.058. For group 2, it was 0.095 ± 0.055. The difference between both groups was statistically significant (p = 0.03). For group 1, the mean contact area was 49.91 ± 21.47 mm2. For group 2, it was 51.42 ± 19.76 mm2. The difference was statistically not significant (p = 0.4). The correlation between the contact area and the chewing efficiency in both groups was statistically significant and it was negative (in class I p = 0 and R = -0.616; in class II p = 0.01 and R = -0.408). Conclusion The Chewing is better for patients with Angle's Class I malocclusion. The contact area is higher. Larger occlusal contact area leads to higher masticatory efficiency. Further studies should be conducted.
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Affiliation(s)
- Ahmed Hamdi
- Faculty of Dental Medicine Monastir Tunisia; University of Monastir
| | - Rim Kallala
- Faculty of Dental Medicine Monastir Tunisia, University of Monastir, Department of Fixed Prosthodontics, Laboratory of Dental Anatomy, Research Laboratory of Occlusodontics and Ceramic Prostheses LR16ES15, 5000 Monastir, Tunisia
| | - Belhassen Harzallah
- Faculty of dental Medicine Monastir Tunisia, University of Monastir, Department of fixed prosthodontics, Research laboratory of Occlusodontics and Ceramic Prostheses LR16ES15, 5000, Monastir, Tunisia
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Nalamliang N, Thongudomporn U. Effects of class II intermaxillary elastics on masticatory muscle activity balance, occlusal contact area and masticatory performance: A multicenter randomised controlled trial. J Oral Rehabil 2023; 50:131-139. [PMID: 36435988 DOI: 10.1111/joor.13395] [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: 05/02/2022] [Revised: 08/04/2022] [Accepted: 11/23/2022] [Indexed: 11/29/2022]
Abstract
BACKGROUND Bilateral Class II intermaxillary elastics (CII elastics) are commonly used in orthodontics; however, the effects of CII elastics on masticatory muscle activity and the occlusal contact area have not been studied. OBJECTIVES To evaluate the short-term effects of CII elastics on masticatory muscle activity balance, occlusal contact area and masticatory performance in a group of adult orthodontic patients after 3 months. MATERIALS AND METHODS Forty-three patients with a <3 mm Class II molar relationship receiving ongoing treatment with fixed appliances were recruited. The experimental group (n = 21) wore CII elastics (100-150 g/side) full time; the control group (n = 22) did not wear CII elastics. Surface electromyography, the areas of occlusal contact and near contact (ACNC) and the median particle size of a test food were assessed prior to (T0) and after one (T1) and 3 months (T2). Within- and between-group differences were analysed and the relationships between changes in dependent variables were examined (α = 0.05). RESULTS At T2, the experimental group showed better masticatory muscle activity balance (p < .001) and masticatory performance (p < .05) than controls. Both masticatory muscle activity balance (p < .001) and masticatory performance (p < .001) significantly improved in the experimental group between T0 and T2. The changes in masticatory muscle activity balance and masticatory performance were significantly related (p < .05). No significant changes in cumulative ACNC or ACNC balance were observed (p > .05). CONCLUSION After 3 months, CII elastics improved masticatory muscle activity balance, which led to better masticatory performance.
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Affiliation(s)
- Napat Nalamliang
- Department of Occlusion, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand
| | - Udom Thongudomporn
- Orthodontic Section, Department of Preventive Dentistry, Faculty of Dentistry, Prince of Songkla University, Songkhla, Thailand
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Ryakhovsky AN. [3D analysis of occlusal surfaces of teeth and their contacts. Part I. Development of a method for assessing the area of the occlusal surface, the severity of its relief and the histogram of contacts]. STOMATOLOGII︠A︡ 2021; 100:37-43. [PMID: 34357726 DOI: 10.17116/stomat202110004137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The article is devoted to the development of methods and software for 3D analysis of the occlusal surface of teeth and occlusal contacts between antagonists. An algorithm for accurately determining the boundaries of the occlusal surface on the tooth surface for subsequent quantitative analysis: the area of the occlusal surface, the relief index, and the height of the cusps is presented. The area of not only direct contacts, but also near-contact zones in any of the selected surface separation ranges is quantified. Examples with geometric primitives and clinical examples explain the features and interpretation of 3D analysis datas obtained using the developed software.
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Affiliation(s)
- A N Ryakhovsky
- Central Research Institute of Dentistry and Maxillofacial Surgery, Moscow, Russia
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The rationale for orthodontic retention: piecing together the jigsaw. Br Dent J 2021; 230:739-749. [PMID: 34117429 DOI: 10.1038/s41415-021-3012-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 03/08/2021] [Indexed: 12/12/2022]
Abstract
Retaining teeth in their corrected positions following orthodontic treatment is one of the most challenging aspects of orthodontic practice. Despite much research, the rationale for retention is not entirely clear. Teeth tend to revert to their pre-treatment positions due to periodontal and gingival, soft tissue, occlusal and growth factors. Changes may also follow normal dentofacial ageing and are unpredictable with great variability. In this overview, each of these factors are discussed with their implications for retention, along with adjunctive procedures to minimise relapse. The state of current knowledge, methods used to assess relapse, factors regarded as predictive of or associated with stability as well as overcorrection are outlined. Potential areas requiring further investigation are suggested. The way in which the clinician may manage current retention practice, with a need for individualised retention plans and selective retainer wear, is also considered.
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The Effects of Orthodontic Brackets on the Time and Accuracy of Digital Impression Taking. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18105282. [PMID: 34065653 PMCID: PMC8156877 DOI: 10.3390/ijerph18105282] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 05/07/2021] [Accepted: 05/13/2021] [Indexed: 11/29/2022]
Abstract
Background: The aim of the study was to study how the presence or the type of the orthodontic brackets influence the time measurement and accuracy of impressions using a digital oral scanner. Methods: The same models were divided into the control group (the model without a bracket), MB group (the model with a metal bracket), and CB group (the model with a monocrystalline bracket). Subsequently, scanning was conducted five times for each model using the Trios Pod 2®. Simultaneously, the duration for taking the digital impression was measured. The degree of accuracy was compared among the three groups. Results: As compared with the control group, scanning took 53.3 s longer in the MB group and 194.23 s longer in the CB group. In the canine and the first molar, the mean values of errors were compared between the left and right sides; in both the canine and the first molar, errors between the control group and the CB group were the greatest. Conclusions: Following a comparison of the duration and accuracy of the impressions between the three groups, our results suggest that its degree was the highest in the CB group where a monocrystalline bracket was attached.
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Lee Y, Chun Y. An investigation into structural behaviors of skulls chewing food in different occlusal relationships using FEM. Clin Exp Dent Res 2020; 6:277-285. [PMID: 32558315 PMCID: PMC7301394 DOI: 10.1002/cre2.273] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 11/29/2019] [Accepted: 11/29/2019] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVES This study aims to investigate the effect of different occlusal relationships on skull structural and mechanical behaviors through simulation of chewing food. METHODS Finite element (FE) skull models of occlusion for Class I, end-on Class II, and full-cusp Class II were generated. End-on Class II and full-cusp Class II were chosen as mild and severe Class II occlusions, respectively. A simplified food bolus was introduced between the upper and lower dentition of the right molars. Chewing food was simulated in the skulls by moving the mandible. An experiment was conducted to measure strains at selective locations and compared them to the analytical results for validation. RESULTS In the early stages of mandibular movement, masticatory forces predicted from the skull models without food were lower than the skull models with food but increased drastically after occluding teeth full enough. As a result, the relationship between masticatory force and mandible movement shows that there is no significant difference between the skull models with food and without food in the range of human masticatory force, approximately 250 N. In all the cases of skulls including a food bolus, stress was similarly propagated from the mandible to the maxilla and concentrated in the same regions, including the mandibular notch and alveolar bone around the lower molars. CONCLUSION It is predicted that there is no significant difference of bite force-mandible movement relationships and stress distributions of skull and teeth, between end-on Class II and full-cusp Class II models. When simulating chewing activities on candy and carrot, it is also found that there is no difference of masticatory performance between Class II occlusions, from structural as well as mechanical perspectives.
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Affiliation(s)
- Yeo‐Kyeong Lee
- Architectural and Urban System Engineering, Division of Sustainable Systems Engineering, ELTEC College of EngineeringEwha Womans UniversitySeoulSouth Korea
| | - Youn‐Sic Chun
- Orthodontics & dentofacial orthopedics, School of MedicineEwha Womans UniversitySeoulSouth Korea
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Hwang S, Choi YJ, Jung S, Kim S, Chung CJ, Kim KH. Posterior dental compensation and occlusal function in adults with different sagittal skeletal malocclusions. Korean J Orthod 2020; 50:98-107. [PMID: 32257935 PMCID: PMC7093660 DOI: 10.4041/kjod.2020.50.2.98] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 07/30/2019] [Accepted: 09/09/2019] [Indexed: 11/11/2022] Open
Abstract
Objective The aim of this study was to compare posterior tooth inclinations, occlusal force, and contact area of adults with different sagittal malocclusions. Methods Transverse skeletal parameters and posterior tooth inclinations were evaluated using cone beam computed tomography images, and occlusal force as well as contact area were assessed using pressure-sensitive films in 124 normodivergent adults. A linear mixed model was used to cluster posterior teeth into maxillary premolar, maxillary molar, mandibular premolar, and mandibular molar groups. Differences among Class I, II, and III groups were compared using an analysis of variance test and least significant difference post-hoc test. Correlations of posterior dental inclinations to occlusal function were analyzed using Pearson's correlation analysis. Results In male subjects, maxillary premolars and molars had the smallest inclinations in the Class II group while maxillary molars had the greatest inclinations in the Class III group. In female subjects, maxillary molars had the smallest inclinations in the Class II group, while maxillary premolars and molars had the greatest inclinations in the Class III group. Occlusal force and contact area were not significantly different among Class I, II, and III groups. Conclusions Premolar and molar inclinations showed compensatory inclinations to overcome anteroposterior skeletal discrepancy in the Class II and III groups; however, their occlusal force and contact area were similar to those of Class I group. In subjects with normodivergent facial patterns, although posterior tooth inclinations may vary, difference in occlusal function may be clinically insignificant in adults with Class I, II, and III malocclusions.
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Affiliation(s)
- Soonshin Hwang
- Department of Orthodontics, Gangnam Severance Dental Hospital, College of Dentistry, Yonsei University, Seoul, Korea
- Department of Orthodontics and Institute of Craniofacial Deformity, College of Dentistry, Yonsei University, Seoul, Korea
| | - Yoon Jeong Choi
- Department of Orthodontics and Institute of Craniofacial Deformity, College of Dentistry, Yonsei University, Seoul, Korea
| | - Sooin Jung
- Department of Orthodontics, Gangnam Severance Dental Hospital, College of Dentistry, Yonsei University, Seoul, Korea
- Department of Orthodontics and Institute of Craniofacial Deformity, College of Dentistry, Yonsei University, Seoul, Korea
| | - Sujin Kim
- Department of Orthodontics, Gangnam Severance Dental Hospital, College of Dentistry, Yonsei University, Seoul, Korea
- Department of Orthodontics and Institute of Craniofacial Deformity, College of Dentistry, Yonsei University, Seoul, Korea
| | - Chooryung J. Chung
- Department of Orthodontics, Gangnam Severance Dental Hospital, College of Dentistry, Yonsei University, Seoul, Korea
- Department of Orthodontics and Institute of Craniofacial Deformity, College of Dentistry, Yonsei University, Seoul, Korea
| | - Kyung-Ho Kim
- Department of Orthodontics, Gangnam Severance Dental Hospital, College of Dentistry, Yonsei University, Seoul, Korea
- Department of Orthodontics and Institute of Craniofacial Deformity, College of Dentistry, Yonsei University, Seoul, Korea
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Ayuso‐Montero R, Mariano‐Hernandez Y, Khoury‐Ribas L, Rovira‐Lastra B, Willaert E, Martinez‐Gomis J. Reliability and Validity of T‐scan and 3D Intraoral Scanning for Measuring the Occlusal Contact Area. J Prosthodont 2019; 29:19-25. [DOI: 10.1111/jopr.13096] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/26/2019] [Indexed: 02/02/2023] Open
Affiliation(s)
- Raul Ayuso‐Montero
- Department of ProsthodonticsSchool of DentistryFaculty of Medicine and Health SciencesUniversity of BarcelonaIDIBELL Spain
- Oral Health and Masticatory System Group(Bellvitge Biomedical Research Institute) IDIBELL L'Hospitalet de Llobregat Barcelona Spain
| | | | - Laura Khoury‐Ribas
- Department of ProsthodonticsSchool of DentistryFaculty of Medicine and Health SciencesUniversity of BarcelonaIDIBELL Spain
- Oral Health and Masticatory System Group(Bellvitge Biomedical Research Institute) IDIBELL L'Hospitalet de Llobregat Barcelona Spain
| | - Bernat Rovira‐Lastra
- Department of ProsthodonticsSchool of DentistryFaculty of Medicine and Health SciencesUniversity of BarcelonaIDIBELL Spain
- Oral Health and Masticatory System Group(Bellvitge Biomedical Research Institute) IDIBELL L'Hospitalet de Llobregat Barcelona Spain
| | - Eva Willaert
- Department of ProsthodonticsSchool of DentistryFaculty of Medicine and Health SciencesUniversity of BarcelonaIDIBELL Spain
- Oral Health and Masticatory System Group(Bellvitge Biomedical Research Institute) IDIBELL L'Hospitalet de Llobregat Barcelona Spain
| | - Jordi Martinez‐Gomis
- Department of ProsthodonticsSchool of DentistryFaculty of Medicine and Health SciencesUniversity of BarcelonaIDIBELL Spain
- Oral Health and Masticatory System Group(Bellvitge Biomedical Research Institute) IDIBELL L'Hospitalet de Llobregat Barcelona Spain
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Bae J, Son WS, Kim SS, Park SB, Kim YI. Comparison of masticatory efficiency according to Angle's classification of malocclusion. Korean J Orthod 2017; 47:151-157. [PMID: 28523241 PMCID: PMC5432436 DOI: 10.4041/kjod.2017.47.3.151] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 10/27/2016] [Accepted: 11/01/2016] [Indexed: 12/05/2022] Open
Abstract
Objective The objective of this study was to investigate the differences in masticatory efficiency among patients with different Angle's classes of malocclusion and to assess the correlation between masticatory efficiency and the occlusal contact area. Methods The mixing ability index (MAI) was calculated for measuring masticatory efficiency of 61 adult patients according to Angle's classifications of malocclusion. The study included 25, 15, and 21 patients with Angle's Class I, II, and III malocclusions, respectively. Silicone interocclusal recording material was used to measure the occlusal contact area. Results Both the MAI and occlusal contact area showed the highest average values in the Class I malocclusion group, followed by the Class II and Class III malocclusion groups. No significant difference was observed in the MAI values between the Class I and Class II malocclusion groups (p > 0.05), whereas a significant difference was observed between the Class I and Class III malocclusion groups (p < 0.01) and between the Class II and Class III malocclusion groups (p < 0.05). A weak positive correlation was also observed between the MAI and occlusal contact area (p < 0.01, r2 = 0.13). Conclusions The results of this study indicated that masticatory efficiency was the highest in patients with Angle's Class I malocclusion, followed by those with Angle's Class II and Angle's Class III malocclusions. Moreover, a weak positive correlation was observed between masticatory efficiency and the occlusal contact area.
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Affiliation(s)
- Jungin Bae
- Department of Orthodontics, Pusan National University Dental Hospital, Yangsan, Korea
| | - Woo-Sung Son
- Department of Orthodontics, Pusan National University Dental Hospital, Yangsan, Korea
| | - Seong-Sik Kim
- Department of Orthodontics, Pusan National University Dental Hospital, Yangsan, Korea
| | - Soo-Byung Park
- Department of Orthodontics, Pusan National University Dental Hospital, Yangsan, Korea
| | - Yong-Il Kim
- Department of Orthodontics, Pusan National University Dental Hospital, Yangsan, Korea.,Dental Research Institute, Pusan National University Dental Hospital, Yangsan, Korea.,Institute of Translational Dental Sciences, Pusan National University, Busan, Korea
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Yoon W, Hwang S, Chung C, Kim KH. Changes in occlusal function after extraction of premolars: 2-year follow-up. Angle Orthod 2017; 87:703-708. [PMID: 28485615 DOI: 10.2319/112116-836.1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVE To determine the effects of extraction and the number of teeth extracted on changes in occlusal function by measuring occlusal contact area and force before and after orthodontic treatment with a fixed appliance. MATERIALS AND METHODS Female patients treated with a fixed appliance were divided into nonextraction (n = 36), two maxillary premolar extraction (n = 31), and four premolar extraction (n = 18) groups. Bite pressure-sensitive films were used to analyze the occlusal contact area and force. Measurements were performed before treatment (Pre-Tx), immediately afterward (After-Tx), and 2 years later (2Y After-Tx). The data were analyzed using a linear mixed model and the post hoc Bonferroni test. RESULTS The occlusal contact area and force after treatment decreased significantly compared with Pre-Tx values but were increased 2 years later in all groups. There were no significant differences in occlusal contact area or force during the entire observation period among the three groups (P > .05). The occlusal contact area and force in the nonextraction and two maxillary premolar extraction groups recovered to Pre-Tx levels 2 years later (P > .05). The occlusal contact area in the four premolar extraction group was significantly lower than the Pre-Tx level after 2 years of retention (P < .05). CONCLUSIONS The occlusal contact area and force showed a tendency to decrease immediately after treatment and then gradually increase to pretreatment levels during the observation period. However, the occlusal contact area did not recover fully after 2 years in the four premolar extraction group.
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