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Xu S, Peng H, Yang L, Zhong W, Gao X, Song J. An Automatic Grading System for Orthodontically Induced External Root Resorption Based on Deep Convolutional Neural Network. JOURNAL OF IMAGING INFORMATICS IN MEDICINE 2024; 37:1800-1811. [PMID: 38393620 PMCID: PMC11300848 DOI: 10.1007/s10278-024-01045-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 02/09/2024] [Accepted: 02/09/2024] [Indexed: 02/25/2024]
Abstract
Orthodontically induced external root resorption (OIERR) is a common complication of orthodontic treatments. Accurate OIERR grading is crucial for clinical intervention. This study aimed to evaluate six deep convolutional neural networks (CNNs) for performing OIERR grading on tooth slices to construct an automatic grading system for OIERR. A total of 2146 tooth slices of different OIERR grades were collected and preprocessed. Six pre-trained CNNs (EfficientNet-B1, EfficientNet-B2, EfficientNet-B3, EfficientNet-B4, EfficientNet-B5, and MobileNet-V3) were trained and validated on the pre-processed images based on four different cross-validation methods. The performances of the CNNs on a test set were evaluated and compared with those of orthodontists. The gradient-weighted class activation mapping (Grad-CAM) technique was used to explore the area of maximum impact on the model decisions in the tooth slices. The six CNN models performed remarkably well in OIERR grading, with a mean accuracy of 0.92, surpassing that of the orthodontists (mean accuracy of 0.82). EfficientNet-B4 trained with fivefold cross-validation emerged as the final OIERR grading system, with a high accuracy of 0.94. Grad-CAM revealed that the apical region had the greatest effect on the OIERR grading system. The six CNNs demonstrated excellent OIERR grading and outperformed orthodontists. The proposed OIERR grading system holds potential as a reliable diagnostic support for orthodontists in clinical practice.
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Affiliation(s)
- Shuxi Xu
- College of Stomatology, Chongqing Medical University, Chongqing, 401147, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, 401147, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, 401147, China
| | - Houli Peng
- College of Stomatology, Chongqing Medical University, Chongqing, 401147, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, 401147, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, 401147, China
| | - Lanxin Yang
- College of Stomatology, Chongqing Medical University, Chongqing, 401147, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, 401147, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, 401147, China
| | - Wenjie Zhong
- College of Stomatology, Chongqing Medical University, Chongqing, 401147, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, 401147, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, 401147, China
| | - Xiang Gao
- College of Stomatology, Chongqing Medical University, Chongqing, 401147, China.
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, 401147, China.
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, 401147, China.
| | - Jinlin Song
- College of Stomatology, Chongqing Medical University, Chongqing, 401147, China.
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, 401147, China.
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, 401147, China.
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Kuharattanachai K, Jotikasthira D, Rangsri W, Tripuwabhrut K. Effect of occlusal hypofunction on centre of resistance in maxillary central incisor using the finite element method. J Orthod 2024; 51:19-27. [PMID: 37269106 DOI: 10.1177/14653125231176575] [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] [Indexed: 06/04/2023]
Abstract
OBJECTIVES To determine differences in the location of centre of resistance (Cres) between functional and hypofunctional teeth and to evaluate the relationship between the pulp cavity volume and locations of the Cres, using the finite element (FE) method. DESIGN Retrospective cohort study. PARTICIPANTS FE models of right maxillary central incisor, derived from cone-beam computed tomography (CBCT) images of 46 participants, were divided into normal function (n = 23) and hypofunction (n = 23) groups using anterior overbite and cephalometric measurements. METHODS Measurements of the tooth and pulp cavity volume were made from the CBCT. Cres levels were presented as percentages of the root length from the root's apex. All data were analysed and compared using the independent t-test (P < 0.05). The relationship between the location of Cres and volume ratios were evaluated statistically. RESULTS The means of the pulp cavity/tooth volume and root canal/ root volume ratio of the maxillary central incisor in the anterior open bite group were significantly greater than those in the normal group. The average location of Cres in the anterior open bite group was 0.6 mm (3.7%) apically from the normal group, measured from root apex. The difference was statistically significant (P < 0.01). There was a significant correlation between root canal/root volume ratio and locations of Cres (r = -0.780, P < 0.001). CONCLUSIONS The Cres in the hypofunctional group was located more apical than the functional group. As the pulp cavity volume increased, the level of Cres shifted apically.
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Affiliation(s)
- Kachaphol Kuharattanachai
- Department of Orthodontics and Pediatric Dentistry, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand
| | - Dhirawat Jotikasthira
- Department of Orthodontics and Pediatric Dentistry, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand
| | - Wetchayan Rangsri
- Department of Mechanical Engineering, Faculty of Engineering, Chiang Mai University, Chiang Mai, Thailand
| | - Kanich Tripuwabhrut
- Department of Orthodontics and Pediatric Dentistry, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand
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Terada K, Kameda T, Sakamoto M. Three-dimensional positions of the center of resistance of the maxillary canine distal movement under orthodontic force loading. Dent Mater J 2024; 43:44-51. [PMID: 38044144 DOI: 10.4012/dmj.2023-160] [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] [Indexed: 12/05/2023]
Abstract
Using finite-element analysis, we aimed to determine the center of resistance (CRes) of the maxillary canine for setting orthodontic forces. The inclination of the canine was measured by first loading from the mesial to the distal side of the mesial root surface, then the position and direction of the load that minimized the inclination were investigated. The CRes was defined as the set of midpoints of the minimum distances between two inclination lines. Twenty-one CRes values were calculated from a set of seven lines. These CRes data were then aggregated as a 95% confidence ellipsoid of width 0.170×0.016×0.009 mm with center points 4.269, 0.224, and 4.315 mm in the apical, mesial, and lingual directions from the origin, respectively. Further studies are required to effectively apply the CRes identified in this study to clinical applications.
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Affiliation(s)
- Kazuto Terada
- Orthodontic Dentistry, The Nippon Dental University Niigata Hospital
| | - Takashi Kameda
- Department of Orthodontics, The Nippon Dental University at Niigata
| | - Makoto Sakamoto
- Department of Health Sciences, Niigata University School of Medicine
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Schmid JQ, Gerberding E, Hohoff A, Kleinheinz J, Stamm T, Middelberg C. Non-Surgical Transversal Dentoalveolar Compensation with Completely Customized Lingual Appliances versus Surgically Assisted Rapid Palatal Expansion in Adults-Tipping or Translation in Posterior Crossbite Correction? J Pers Med 2023; 13:jpm13050807. [PMID: 37240977 DOI: 10.3390/jpm13050807] [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: 04/13/2023] [Revised: 05/04/2023] [Accepted: 05/06/2023] [Indexed: 05/28/2023] Open
Abstract
The aim of this study was to investigate buccolingual tooth movements (tipping/translation) in surgical and nonsurgical posterior crossbite correction. A total of 43 patients (f/m 19/24; mean age 27.6 ± 9.5 years) treated with surgically assisted rapid palatal expansion (SARPE) and 38 patients (f/m 25/13; mean age 30.4 ± 12.9 years) treated with dentoalveolar compensation using completely customized lingual appliances (DC-CCLA) were retrospectively included. Inclination was measured on digital models at canines (C), second premolars (P2), first molars (M1), and second molars (M2) before (T0) and after (T1) crossbite correction. There was no statistically significant difference (p > 0.05) in absolute buccolingual inclination change between both groups, except for the upper C (p < 0.05), which were more tipped in the surgical group. Translation, i.e., bodily tooth movements that cannot be explained by pure uncontrolled tipping, could be observed with SARPE in the maxilla and with DC-CCLA in both jaws. Dentoalveolar transversal compensation with completely customized lingual appliances does not cause greater buccolingual tipping compared to SARPE.
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Affiliation(s)
- Jonas Q Schmid
- Department of Orthodontics, University of Münster, 48149 Münster, Germany
| | - Elena Gerberding
- Department of Orthodontics, Hannover Medical School (MHH), 30625 Hannover, Germany
- Private Practice, 49152 Bad Essen, Germany
| | - Ariane Hohoff
- Department of Orthodontics, University of Münster, 48149 Münster, Germany
| | - Johannes Kleinheinz
- Department of Cranio-Maxillofacial Surgery, University of Münster, 48149 Münster, Germany
| | - Thomas Stamm
- Department of Orthodontics, University of Münster, 48149 Münster, Germany
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Polizzi A, Quinzi V, Ronsivalle V, Venezia P, Santonocito S, Lo Giudice A, Leonardi R, Isola G. Tooth automatic segmentation from CBCT images: a systematic review. Clin Oral Investig 2023:10.1007/s00784-023-05048-5. [PMID: 37148371 DOI: 10.1007/s00784-023-05048-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Accepted: 04/26/2023] [Indexed: 05/08/2023]
Abstract
OBJECTIVES To describe the current state of the art regarding technological advances in full-automatic tooth segmentation approaches from 3D cone-beam computed tomography (CBCT) images. MATERIALS AND METHODS In March 2023, a search strategy without a timeline setting was carried out through a combination of MeSH terms and free text words pooled through Boolean operators ('AND', 'OR') on the following databases: PubMed, Scopus, Web of Science and IEEE Explore. Randomized and non-randomized controlled trials, cohort, case-control, cross-sectional and retrospective studies in the English language only were included. RESULTS The search strategy identified 541 articles, of which 23 have been selected. The most employed segmentation methods were based on deep learning approaches. One article exposed an automatic approach for tooth segmentation based on a watershed algorithm and another article used an improved level set method. Four studies presented classical machine learning and thresholding approaches. The most employed metric for evaluating segmentation performance was the Dice similarity index which ranged from 90 ± 3% to 97.9 ± 1.5%. CONCLUSIONS Thresholding appeared not reliable for tooth segmentation from CBCT images, whereas convolutional neural networks (CNNs) have been demonstrated as the most promising approach. CNNs could help overcome tooth segmentation's main limitations from CBCT images related to root anatomy, heavy scattering, immature teeth, metal artifacts and time consumption. New studies with uniform protocols and evaluation metrics with random sampling and blinding for data analysis are encouraged to objectively compare the different deep learning architectures' reliability. CLINICAL RELEVANCE Automatic tooth segmentation's best performance has been obtained through CNNs for the different ambits of digital dentistry.
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Affiliation(s)
- Alessandro Polizzi
- Department of General Surgery and Surgical-Medical Specialties, School of Dentistry, University of Catania, AOU "Policlinico-San Marco", Via S. Sofia 78, 95124, Catania, Italy.
- Department of Life, Health & Environmental Sciences, Postgraduate School of Orthodontics, University of L'Aquila, 67100, L'Aquila, Italy.
| | - Vincenzo Quinzi
- Department of Life, Health & Environmental Sciences, Postgraduate School of Orthodontics, University of L'Aquila, 67100, L'Aquila, Italy
| | - Vincenzo Ronsivalle
- Department of General Surgery and Surgical-Medical Specialties, School of Dentistry, University of Catania, AOU "Policlinico-San Marco", Via S. Sofia 78, 95124, Catania, Italy
| | - Pietro Venezia
- Department of General Surgery and Surgical-Medical Specialties, School of Dentistry, University of Catania, AOU "Policlinico-San Marco", Via S. Sofia 78, 95124, Catania, Italy
| | - Simona Santonocito
- Department of General Surgery and Surgical-Medical Specialties, School of Dentistry, University of Catania, AOU "Policlinico-San Marco", Via S. Sofia 78, 95124, Catania, Italy
| | - Antonino Lo Giudice
- Department of General Surgery and Surgical-Medical Specialties, School of Dentistry, University of Catania, AOU "Policlinico-San Marco", Via S. Sofia 78, 95124, Catania, Italy
| | - Rosalia Leonardi
- Department of General Surgery and Surgical-Medical Specialties, School of Dentistry, University of Catania, AOU "Policlinico-San Marco", Via S. Sofia 78, 95124, Catania, Italy
| | - Gaetano Isola
- Department of General Surgery and Surgical-Medical Specialties, School of Dentistry, University of Catania, AOU "Policlinico-San Marco", Via S. Sofia 78, 95124, Catania, Italy
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Kuruthukulam RM, Patil AS. The center of resistance of a tooth: a review of the literature. Biophys Rev 2023; 15:35-41. [PMID: 36909954 PMCID: PMC9995625 DOI: 10.1007/s12551-023-01042-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 01/05/2023] [Indexed: 01/18/2023] Open
Abstract
The center of resistance is considered the fundamental reference point for controlled tooth movement. Accurate determination of its location can greatly enhance the efficiency of orthodontic treatment. The purpose of this review was to analyse the scientific literature related to the location of center of resistance of tooth determined by various approaches. The literature describes three essential approaches to identify the center of resistance point, one being experimental in nature, one based on an analytical physical approach, and one using a numerical physical approach that uses a finite element simulation. A review on data referring to the location of the center of resistance, limited to single rooted tooth has been performed from electronic databases. It showed variation in its location related to the assumptions used in the model. The center of resistance of tooth therefore cannot be considered a static point, but rather as the composite point of all factors offering resistance to the applied force such as the tooth morphology and mass distribution within the tooth, the structure of the periodontium, the alveolar bone level, the adjacent teeth and direction of force applied.
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Affiliation(s)
- Reene Mary Kuruthukulam
- Department of Orthodontics and Dentofacial Orthopaedics, Bharati Vidyapeeth Dental College and Hospital, Pune, Maharashtra India
| | - Amol Somaji Patil
- Department of Orthodontics and Dentofacial Orthopaedics, Bharati Vidyapeeth Dental College and Hospital, Pune, Maharashtra India
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Terada K, Kameda T, Sakamoto M. Three-dimensional location and distribution of the center of resistance in the maxillary first molar applied to occlusal force. Dent Mater J 2023; 42:133-139. [PMID: 36351599 DOI: 10.4012/dmj.2022-136] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We aimed to investigate the center of resistance (CRes) of the maxillary first molar to set the occlusal force through finite element analysis. The inclination of the molar was measured, with loading to the root on the crown, and the position and direction of the load that minimized the inclination were investigated. The CRes was defined as the set of midpoints of the minimum distances between the two lines. Nine hundred and ninety CRes points were estimated from forty-five lines. The CRes was estimated as the point 1.22 mm (Z), -0.74 mm (X), and 0.23 mm (Y) from the origin in the apical, distal, and buccal side directions, respectively, with an ellipsoid area of 1.578 (Z) mm×0.097 (X) mm×0.100 (Y) mm. Further research is required to make effective use of the CRes identified in this study for clinical applications.
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Affiliation(s)
| | - Takashi Kameda
- Department of Orthodontics, The Nippon Dental University at Niigata
| | - Makoto Sakamoto
- Department of Health Sciences, Niigata University School of Medicine
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Nowak CM, Othman A, Ströbele DA, von See C. Comparative mechanical testing for different orthodontic aligner materials over time - in vitro study. J Clin Exp Dent 2022; 14:e457-e463. [PMID: 35765355 PMCID: PMC9233917 DOI: 10.4317/jced.59569] [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: 03/10/2022] [Accepted: 04/11/2022] [Indexed: 11/08/2022] Open
Abstract
Background The purpose of the present study is to mechanically evaluate and compare the forces over 12 hours on different orthodontic aligners manufactured by Polyethylene terephthalate glycol (PETG).
Material and Methods Twelve orthodontic aligner specimens will be produced by a thermoforming laboratory vacuum machine. All specimens will be divided into two equal groups, group A representing Duran (Scheu Dental GmbH, Iserlohn, Germany) and group B representing Erkodur (Erkodent, Pfalzgrafenweiler, Germany). These specimens will be fabricated via CAD/CAM technology by scanning a Frasaco model (Henry Schein Dental, Gallin, Germany) using D 800 (3Shape, Copenhagen, Denmark) and printed via a Varseo S machine using Varseo ModelWax material (BEGO, Bremen, Germany). Group A specimens are manufactured by a Twinster thermoforming machine (Scheu Dental GmbH, Iserlohn, Germany) while group B is produced using Erkoform thermoforming machine (Erkodent, Pfalzgrafenweiler, Germany). Afterwards, a tooth will be removed from the printed model and replaced by an ivory tooth (Henry Schein Dental, Gallin, Germany) to apply forces at a predicted measured centre of resistance. The universal testing machine Z010 (ZwickRoell, Ulm, Germany) will be used for mechanical testing with 0.3 mm displacement over 12 hours. Statistical analysis was performed using Sigmaplot 13.0 (Systat Software GmbH, Erkrath, Germany). Behaviours over time were analysed using R2-regression analysis (SPSS 26.0, IBM SPSS Statistics, Armonk, USA).
Results There is no statistically significant difference in the maximum force between both groups (p=0.071). The mechanical testing over 12 hours showed cubic properties.
Conclusions The PETG material has no influence on the produced mechanical forces regardless of the manufacturing company. The forces over time showed no tendency towards a lower boundary of force. Key words:Mechanical testing, CAD/CAM, orthodontics, thermoplastic aligner materials.
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Affiliation(s)
- Clara-Marie Nowak
- Researcher in the digital technologies in dentistry and CAD/CAM department- Danube Private University- Austria
| | - Ahmed Othman
- Assistant Professor, Research Center for Digital Technologies in Dentistry and CAD/CAM, Department of Dentistry, Faculty of Medicine and Dentistry, Danube Private University, 3500 Krems, Austria
| | - Dragan-Alexander Ströbele
- Researcher in the digital technologies in dentistry and CAD/CAM department- Danube Private University- Austria
| | - Constantin von See
- Professor and Director of Research Center for Digital Technologies in Dentistry and CAD/CAM, Department of Dentistry, Faculty of Medicine and Dentistry, Danube Private University, 3500 Krems, Austria
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Kuharattanachai K, Rangsri W, Jotikasthira D, Khemaleelakul W, Tripuwabhrut K. Does pulp cavity affect the center of resistance in three-dimensional tooth model? A finite element method study. Clin Oral Investig 2022; 26:6177-6186. [PMID: 35641835 DOI: 10.1007/s00784-022-04567-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 05/22/2022] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To compare the center of resistance (Cres) of the maxillary central incisor in models with and without the pulp cavity and to evaluate the association of pulp cavity/tooth volume ratio and difference in Cres position between the two models. MATERIALS AND METHODS CBCT images of the right maxillary central incisor were collected from 18 subjects. Pulp cavity/tooth volume ratio was measured, and finite element models of teeth and periodontal structures were generated. Cres location was presented as a percentage of root length measured from the root apex. Differences in Cres positions between models were compared using the paired t-test, while the correlation between pulp cavity/tooth volume ratio and a difference in Cres was evaluated by Pearson's correlation coefficient. RESULTS For the pulp cavity model, the average location of the Cres measured from the apex of the root was 58.8% ± 3.0%, which resulted in a difference of 4.1% ± 1.1% (0.5 mm) apically, when compared with the model without pulp cavity. Differences in Cres between the models were statistically significant (P < 0.01), while the correlation between pulp cavity/tooth volume ratio and a difference in Cres between models was significantly positive (r = 0.709, P = 0.001). CONCLUSIONS In the pulp cavity model, the Cres was located in a more apical position. The difference in Cres between models increased as the pulp cavity/tooth volume ratio increased. CLINICAL RELEVANCE The line of force must be applied more apically in the pulp cavity model to achieve the desired orthodontic tooth movement.
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Affiliation(s)
- Kachaphol Kuharattanachai
- Department of Orthodontics and Pediatric Dentistry, Faculty of Dentistry, Chiang Mai University, Suthep Road, Muang, Chiang Mai, 50200, Thailand
| | - Wetchayan Rangsri
- Department of Mechanical Engineering, Faculty of Engineering, Chiang Mai University, Chiang Mai, Thailand
| | - Dhirawat Jotikasthira
- Department of Orthodontics and Pediatric Dentistry, Faculty of Dentistry, Chiang Mai University, Suthep Road, Muang, Chiang Mai, 50200, Thailand
| | - Wikanda Khemaleelakul
- Department of Orthodontics and Pediatric Dentistry, Faculty of Dentistry, Chiang Mai University, Suthep Road, Muang, Chiang Mai, 50200, Thailand
| | - Kanich Tripuwabhrut
- Department of Orthodontics and Pediatric Dentistry, Faculty of Dentistry, Chiang Mai University, Suthep Road, Muang, Chiang Mai, 50200, Thailand.
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Sonone T, Nawab A, Krishnaraj P, Nagar P, Arya, Mohan I. The effects of corticotomy and piezocision in orthodontic canine retraction: A randomized controlled clinical trial. JOURNAL OF PHARMACY AND BIOALLIED SCIENCES 2022; 14:S757-S764. [PMID: 36110789 PMCID: PMC9469311 DOI: 10.4103/jpbs.jpbs_170_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 03/15/2022] [Indexed: 11/10/2022] Open
Abstract
Background: There have been many studies and experiments to evaluate the effectiveness of different types of dental treatment. Maxillary canine extraction is such a dental treatment which can be performed through either alveolar corticotomy (AC) or piezocision (PZ). The current study aims to compare the effectiveness of these two types of dental procedures. It is based on a randomized clinical trial (RCT) through the split-mouth technique supported by a parallel group design. The participants in the trial were selected on the basis of a medical criterion. The clinical trial involved extraction of both the first maxillary premolar teeth through use of orthodontic instruments. This study aims to evaluate the comparative effectiveness of alveolar corticotomy and piezocision corticotomy in acceleration of maxillary canine retraction and how it can be used for expression of multiple bone remodeling gingival crevicular fluid (GCF). As part of this study, a RCT was performed on the basis of split-mouth technique at the Department of Orthodontics of Pontifical Catholic University at Minas Gerais in Brazil. The sample size for the clinical trial consisted of people who required extraction of maxillary premolar teeth after canine extraction. After digital intraoral scans, the cumulative distal movement of canines was measured on the basis of superimposition of digital model and the results were considered as the primary outcome of the study. The GCF bone remodeling samples were considered as the secondary outcomes. Results: 50 patients, involving 22 males and 28 females were analyzed in this particular clinical trial. The age range that was considered for this clinical trial was 19–33 years. In case of understanding the distal movement between control and AC, no statistical significance was observed in Group1 (G1). Lower cumulative cervical and incisal measurements in case of PZ was lower than the measurement in the control state. In all the groups, the expression of the biomarkers had occurred in specific timepoints (P < 0.05) but no distinct pattern was observed. Conclusions: In order to accelerate the maxillary canine retraction, PZ and AC were ineffective. No distinct induction pattern of biomarker expression was noted as well.
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Gandhi V, Luu B, Dresner R, Pierce D, Upadhyay M. Where is the center of resistance of a maxillary first molar? A 3-dimensional finite element analysis. Am J Orthod Dentofacial Orthop 2021; 160:442-450.e1. [PMID: 34272138 DOI: 10.1016/j.ajodo.2020.04.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 03/01/2020] [Accepted: 04/01/2020] [Indexed: 10/20/2022]
Abstract
INTRODUCTION The center of resistance (CRes) is regarded as the fundamental reference point for predictable tooth movement. Accurate estimation can greatly enhance the efficiency of orthodontic tooth movement. Only a handful of studies have evaluated the CRes of a maxillary first molar; however, most had a low sample size (in single digits), used idealized models, or involved 2-dimensional analysis. The objectives of this study were to: (1) determine the 3-dimensional (3D) location of the CRes of maxillary first molars, (2) evaluate its variability in a large sample, and (3) investigate the effects of applying orthodontic load from 2 directions on the location of the CRes. METHODS Cone-beam computed tomography scans of 50 maxillary molars from 25 patients (mean age, 20.8 ± 8.7 years) were used. The cone-beam computed tomography volume images were manipulated to extract 3D biological structures via segmentation. The segmented structures were cleaned and converted into virtual mesh models made of tetrahedral triangles having a maximum edge length of 1 mm. The block, which included the molars and periodontal ligament, consisted of a mean of 7753 ± 2748 nodes and 38,355 ± 14,910 tetrahedral elements. Specialized software was used to preprocess the models to create an assembly and assign material properties, interaction conditions, boundary conditions, and load applications. Specific loads were applied, and custom-designed algorithms were used to analyze the stress and strain to locate the CRes. The CRes was measured in relation to the geometric center of the buccal surface of the molar and the trifurcation of the molar roots. RESULTS The average location of the CRes for the maxillary first molar was 4.94 ± 1.39 mm lingual, 2.54 ± 2.7 mm distal, and 7.86 ± 1.66 mm gingival relative to the geometric center of the buccal surface of the molar and 0.136 ± 1.51 mm lingual (P <0.01), 1.48 ± 2.26 mm distal (P <0.01), and 0.188 ± 1.75 mm gingival (P >0.01) relative to the trifurcation of the molar roots. In the anteroposterior (y-axis) and the vertical (z-axis) planes, the CRes showed significant association with root divergence (P <0.01). CONCLUSIONS The CRes of the maxillary first molar was located apical and distal to the trifurcation area. It showed significant variation in its location. The 3D location of and also varied with the force direction. In some samples, this deviation was large. For accurate and predictable movement, tooth-specific CRes need to be calculated.
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Affiliation(s)
- Vaibhav Gandhi
- Division of Orthodontics, School of Dentistry, University of Louisville, Louisville, KY
| | | | - Rebecca Dresner
- Division of Orthodontics, Department of Craniofacial Sciences, University of Connecticut Health Center, Farmington, CT
| | - David Pierce
- Department of Mechanical Engineering, Department of Biomedical Engineering, and Department of Mathematics, University of Connecticut, Storrs, CT
| | - Madhur Upadhyay
- Division of Orthodontics, Department of Craniofacial Sciences, University of Connecticut Health Center, Farmington, CT.
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Maret D, Vergnes JN, Peters OA, Peters C, Nasr K, Monsarrat P. Recent Advances in Cone-beam CT in Oral Medicine. Curr Med Imaging 2021; 16:553-564. [PMID: 32484089 DOI: 10.2174/1573405615666190114152003] [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: 09/24/2018] [Revised: 12/09/2018] [Accepted: 12/19/2018] [Indexed: 11/22/2022]
Abstract
BACKGROUND The cone-beam computed tomography (CBCT) technology has continuously evolved since its appearance in oral medicine in the early 2000s. OBJECTIVES To present recent advances in CBCT in oral medicine: i) selection of recent and consensual evidence-based sources, ii) structured summary of the information based on an iterative framework and iii) compliance with ethical, public health and patient-centered concerns. MAIN FINDINGS We will focus on technological advances, such as sensors and reconstruction algorithms used to improve the constant quality of the image and dosimetry. CBCT examination is now performed in almost all disciplines of oral medicine: currently, the main clinical disciplines that use CBCT acquisitions are endodontics and oral surgery, with clearly defined indications. Periodontology and ear, nose and throat medicine are more recent fields of application. For a given application and indication, the smallest possible field of view must be used. One of the major challenges in contemporary healthcare is ensuring that technological developments do not take precedence over admitted standards of care. The entire volume should be reviewed in full, with a systematic approach. All findings are noted in the patient's record and explained to the patient, including incidental findings. This presupposes the person reviewing the images is sufficiently trained to interpret such images, inform the patient and organize the clinical pathway, with referrals to other medical or oral medicine specialties as needed. CONCLUSION A close collaboration between dentists, medical physicists, radiologists, radiographers and engineers is critical for all aspects of CBCT technology.
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Affiliation(s)
- Delphine Maret
- Oral Rehabilitation Department, Dental Faculty, Paul Sabatier University, Toulouse University Hospital (CHU de Toulouse), Toulouse, France.,AMIS Laboratory - Laboratoire Anthropologie Moléculaire et Imagerie de Synthèse, Université de Toulouse, UMR 5288 CNRS, UPS, Toulouse, France
| | - Jean-Noel Vergnes
- Epidemiology and Public Health Department, Dental Faculty, Paul Sabatier University, Toulouse University Hospital (CHU de Toulouse), Toulouse, France.,Division of Oral Health and Society, Faculty of Dentistry, McGill University, Montreal, Quebec, Canada
| | - Ove A Peters
- Department of Endodontics, Arthur A. Dugoni School of Dentistry, University of the Pacific, San Francisco, California, United States.,School of Dentistry, University of Queensland, Brisbane, Queensland, Australia
| | - Christine Peters
- Department of Endodontics, Arthur A. Dugoni School of Dentistry, University of the Pacific, San Francisco, California, United States
| | - Karim Nasr
- Oral Rehabilitation Department, Dental Faculty, Paul Sabatier University, Toulouse University Hospital (CHU de Toulouse), Toulouse, France
| | - Paul Monsarrat
- Oral Rehabilitation Department, Dental Faculty, Paul Sabatier University, Toulouse University Hospital (CHU de Toulouse), Toulouse, France.,STROMALab, Université de Toulouse, CNRS ERL 5311, EFS, ENVT, Inserm U1031, UPS, Toulouse, France
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Jiang F, Roberts WE, Liu Y, Shafiee A, Chen J. Mechanical environment for lower canine T-loop retraction compared to en-masse space closure with a power-arm attached to either the canine bracket or the archwire. Angle Orthod 2021; 90:801-810. [PMID: 33378514 DOI: 10.2319/050120-377.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 06/01/2020] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVES To assess the mechanical environment for three fixed appliances designed to retract the lower anterior segment. MATERIALS AND METHODS A cone-beam computed tomography scan provided three-dimensional morphology to construct finite element models for three common methods of lower anterior retraction into first premolar extraction spaces: (1) canine retraction with a T-loop, (2) en-masse space closure with the power-arm on the canine bracket (PAB), and (3) power-arm directly attached to the archwire mesial to the canine (PAW). Half of the symmetric mandibular arch was modeled as a linear, isotropic composite material containing five teeth: central incisors (L1), lateral incisor (L2), canine (L3), second premolar (L4), and first molar (L5). Bonded brackets had 0.022-in slots. Archwire and power-arm components were 0.016 × 0.022 in. An initial retraction force of 125 cN was used for all three appliances. Displacements were calculated. Periodontal ligament (PDL) stresses and distributions were calculated for four invariants: maximum principal, minimum principal, von Mises, and dilatational stresses. RESULTS The PDL stress distributions for the four invariants corresponded to the displacement patterns for each appliance. T-loop tipped the canine(s) and incisors distally. PAB rotated L3 distal in, intruded L2, and extruded L1. PAW distorted the archwire resulting in L3 extrusion as well as lingual tipping of L1 and L2. Maximum stress levels in the PDL were up to 5× greater for the PAW than the T-loop and PAB methods. CONCLUSIONS T-loop of this type is more predictable because power-arms can have rotational and archwire distortion effects that result in undesirable paths of tooth movement.
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Liu Y, Jiang F, Chen J. Can interfaces at bracket-wire and between teeth in multi-teeth finite element model be simplified? INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2019; 35:e3169. [PMID: 30427587 DOI: 10.1002/cnm.3169] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 10/31/2018] [Accepted: 11/02/2018] [Indexed: 06/09/2023]
Abstract
OBJECTIVE Finite element (FE) method's correctness depends heavily on modeling method. This study aimed at determining whether the interfaces at bracket-wire and between teeth can be simplified for multi-teeth FE analysis. METHOD A three-dimensional FE model of a mandible was created from cone-beam computed tomography scan. Due to symmetry, only a half of the mandible was modeled, which consisted of five teeth (first premolar extraction and only first molar), brackets and archwire, periodontal ligament (PDL), cortical bone, and cancellous bone. All the bone, teeth, and PDL were considered to be isotropic and linear. The En-masse retraction case was simulated. A detailed model, which has contact elements between the bracket and archwire and between teeth, was developed to allow relative motion at the interfaces. A model with simplified interfacial conditions, which does not allow the relative motion, was also created. The stresses and displacements as results of the treatment on these two models were calculated and compared. RESULTS The stress and displacement distributions from the detailed model were more close to reality based on the expected displacement pattern of the clinical case than from the simplified model. The maximum stresses from the two methods were also different. The highest stress from the detailed model is twice as high as from the simplified model. CONCLUSIONS The detailed model provides much more reasonable results than the simplified model. Thus, the simplified model should not be used to replace the detailed model if the stress magnitude and highest stress location are the expected outcomes.
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Affiliation(s)
- Yanzhi Liu
- Department of Mechanical Engineering, Indiana University Purdue University Indianapolis (IUPUI), Indianapolis, IN, USA
| | - Feifei Jiang
- Department of Mechanical Engineering, Indiana University Purdue University Indianapolis (IUPUI), Indianapolis, IN, USA
| | - Jie Chen
- Department of Mechanical Engineering, Department of Oral Facial Genetics, Indiana University Purdue University Indianapolis, Indianapolis, IN, USA
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Sifakakis I, Eliades T. Laboratory evaluation of orthodontic biomechanics: The clinical applications revisited. Semin Orthod 2017. [DOI: 10.1053/j.sodo.2017.07.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Galibourg A, Dumoncel J, Telmon N, Calvet A, Michetti J, Maret D. Assessment of automatic segmentation of teeth using a watershed-based method. Dentomaxillofac Radiol 2017; 47:20170220. [PMID: 28937285 DOI: 10.1259/dmfr.20170220] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE Tooth 3D automatic segmentation (AS) is being actively developed in research and clinical fields. Here, we assess the effect of automatic segmentation using a watershed-based method on the accuracy and reproducibility of 3D reconstructions in volumetric measurements by comparing it with a semi-automatic segmentation(SAS) method that has already been validated. METHODS The study sample comprised 52 teeth, scanned with micro-CT (41 µm voxel size) and CBCT (76; 200 and 300 µm voxel size). Each tooth was segmented by AS based on a watershed method and by SAS. For all surface reconstructions, volumetric measurements were obtained and analysed statistically. Surfaces were then aligned using the SAS surfaces as the reference. The topography of the geometric discrepancies was displayed by using a colour map allowing the maximum differences to be located. RESULTS AS reconstructions showed similar tooth volumes when compared with SAS for the 41 µm voxel size. A difference in volumes was observed, and increased with the voxel size for CBCT data. The maximum differences were mainly found at the cervical margins and incisal edges but the general form was preserved. CONCLUSION Micro-CT, a modality used in dental research, provides data that can be segmented automatically, which is timesaving. AS with CBCT data enables the general form of the region of interest to be displayed. However, our AS method can still be used for metrically reliable measurements in the field of clinical dentistry if some manual refinements are applied.
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Affiliation(s)
- Antoine Galibourg
- 1 Laboratoire Anthropologie Moléculaire et Imagerie de Synthèse, Université Paul Sabatier, Toulouse, France.,2 Faculté de Chirurgie Dentaire, Université Paul Sabatier, Centre Hospitalier Universitaire, Toulouse, France
| | - Jean Dumoncel
- 1 Laboratoire Anthropologie Moléculaire et Imagerie de Synthèse, Université Paul Sabatier, Toulouse, France
| | - Norbert Telmon
- 1 Laboratoire Anthropologie Moléculaire et Imagerie de Synthèse, Université Paul Sabatier, Toulouse, France.,3 Service de Médecine Légale, Hôpital de Rangueil, Toulouse, France
| | - Adèle Calvet
- 1 Laboratoire Anthropologie Moléculaire et Imagerie de Synthèse, Université Paul Sabatier, Toulouse, France.,4 Faculté de médecine, Université Paul Sabatier, Centre Hospitalier Universitaire, Toulouse, France
| | - Jérôme Michetti
- 2 Faculté de Chirurgie Dentaire, Université Paul Sabatier, Centre Hospitalier Universitaire, Toulouse, France
| | - Delphine Maret
- 1 Laboratoire Anthropologie Moléculaire et Imagerie de Synthèse, Université Paul Sabatier, Toulouse, France.,2 Faculté de Chirurgie Dentaire, Université Paul Sabatier, Centre Hospitalier Universitaire, Toulouse, France
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