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Ji L, Li B, Wu X. Evaluation of biomechanics using different traction devices in distalization of maxillary molar with clear aligners: a finite element study. Comput Methods Biomech Biomed Engin 2023; 26:559-567. [PMID: 35543236 DOI: 10.1080/10255842.2022.2073789] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The study aimed to mechanically evaluate the tooth displacement of molar distalization by clear aligners combined with micro-implant through different traction devices using finite element analysis. A three-dimensional finite element model of complete maxillary dentition was constructed. Simultaneously move the maxillary first and second molars 0.2 mm distally at the height of 4 mm and 6 mm of micro-implant, and 150 g force was applied to button, precision cut and angelbutton respectively. Initial tooth movement in six different conditions of anterior tooth and molars was analyzed and calculated with ANSYS software. All the upper anterior tooth exhibited uncontrolled labial tipping and intrusion upon the six conditions, and the central incisor showed the largest tendency of crown labial inclination. Among the absolute values of crown-root displacement difference of the anterior tooth in sagittal direction, the angelbutton was the smallest, which means the torque control ability was superior to others. However, button played a more accurate role in the sagittal and vertical control of canine. With the increase of micro-implant height, the torque control ability of anterior tooth was decreased, but the intrusion trend increased. The controlled distal inclination with extrusion of the first molar and uncontrolled distal inclination with intrusion of the second molar were observed, and the angelbutton had more effective horizontal and vertical control on molars, which was close to bodily movement than others. As a new type of traction device, angelbutton has excellent anchorage control effect in clear aligners therapy of molar distalization, which further realizes the accurate expression of orthodontic force.
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Affiliation(s)
- Lili Ji
- Dental Hospital of Shanxi Medical University, Taiyuan, P. R. China
| | - Bing Li
- Dental Hospital of Shanxi Medical University, Taiyuan, P. R. China
| | - Xiuping Wu
- Dental Hospital of Shanxi Medical University, Taiyuan, P. R. China
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2
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Matuck B, Ferraz da Silva LF, Warner BM, Byrd KM. The need for integrated research autopsies in the era of precision oral medicine. J Am Dent Assoc 2023; 154:194-205. [PMID: 36710158 PMCID: PMC9974796 DOI: 10.1016/j.adaj.2022.11.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 11/18/2022] [Accepted: 11/20/2022] [Indexed: 01/29/2023]
Abstract
BACKGROUND Autopsy has benefited the practice of medicine for centuries; however, its use to advance the practice of oral health care is relatively limited. In the era of precision oral medicine, the research autopsy is poised to play an important role in understanding oral-systemic health, including infectious disease, autoimmunity, craniofacial genetics, and cancer. TYPES OF STUDIES REVIEWED The authors reviewed relevant articles that used medical and dental research autopsies to summarize the advantages of minimally invasive autopsies of dental, oral, and craniofacial tissues and to outline practices for supporting research autopsies of the oral and craniofacial complex. RESULTS The authors provide a historical summary of research autopsy in dentistry and provide a perspective on the value of autopsies for high-resolution multiomic studies to benefit precision oral medicine. As the promise of high-resolution multiomics is being realized, there is a need to integrate the oral and craniofacial complex into the practice of autopsy in medicine. Furthermore, the collaboration of autopsy centers with researchers will accelerate the understanding of dental, oral, and craniofacial tissues as part of the whole body. CONCLUSIONS Autopsies must integrate oral and craniofacial tissues as part of biobanking procedures. As new technologies allow for high-resolution, multimodal phenotyping of human samples, using optimized sampling procedures will allow for unprecedented understanding of common and rare dental, oral, and craniofacial diseases in the future. PRACTICAL IMPLICATIONS The COVID-19 pandemic highlighted the oral cavity as a site for viral infection and transmission potential; this was only discovered via clinical autopsies. The realization of the integrated autopsy's value in full body health initiatives will benefit patients across the globe.
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Affiliation(s)
- Bruno Matuck
- Department of Pathology, School of Medicine University of São Paulo, São Paulo, Brazil
- Division of Oral and Craniofacial Health Sciences, Adams School of Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | | | - Blake M. Warner
- Salivary Disorders Unit, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, USA
| | - Kevin Matthew Byrd
- Salivary Disorders Unit, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, USA
- Division of Oral and Craniofacial Health Sciences, Adams School of Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Lab of Oral & Craniofacial Innovation (LOCI), Department of Innovation and Technology Research, ADA Science & Research Institute, Gaithersburg, MD, USA
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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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Matelski J, Rendahl A, Goldschmidt S. Effect of Alternative Palatal Root Access Technique on Fracture Resistance of Root Canal Treated Maxillary Fourth Premolar Teeth in Dogs. Front Vet Sci 2020; 7:600145. [PMID: 33363238 PMCID: PMC7759647 DOI: 10.3389/fvets.2020.600145] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 11/20/2020] [Indexed: 11/13/2022] Open
Abstract
A biomechanical study was performed to identify the effect of different treatment methods for difficult to instrument palatal roots on the fracture resistance of root canal treated maxillary fourth premolar teeth in dogs. Forty maxillary fourth premolar teeth with surrounding alveolar bone were harvested from beagle cadavers. Inclusion criteria included maxillary fourth premolars with no evidence of disease and similar distal root canal volumes on radiographic evaluation. The teeth were randomly divided into a control group and three treatment groups based on the endodontic treatment technique for the palatal root. The control group had a single 2 mm transcoronal access on the mesiobuccal aspect of the tooth to allow instrumentation of both the mesiobuccal and palatal root through a single small access. Alternative treatment modalities that are described for difficult to instrument palatal roots investigated in this study included enlarging the transcoronal mesiobuccal access to 4 mm, making an additional access directly over the palatal root (2 mm), and hemisection with extraction of the palatal root. All teeth had the same distal root access size (2 mm) and relative location. After access, all teeth were filed, shaped, obturated, and restored in the same fashion. Axial compression testing was performed at an angle of 60 degrees to the long axis of the tooth using a universal materials testing machine. The maximum force prior to fracture was determined for each tooth based on a force vs. deflection curve. The mean maximum force prior to fracture for all teeth was 831 N. No significant difference in mean fracture resistance was identified between the control group and treatment groups or between the different treatment groups themselves. Thus, when faced with a difficult to instrument palatal root, the treatment method chosen should be based on operator preference and experience.
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Affiliation(s)
- Jennifer Matelski
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, United States
| | - Aaron Rendahl
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, United States
| | - Stephanie Goldschmidt
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, United States
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Keilig L, Goedecke J, Bourauel C, Daratsianos N, Dirk C, Jäger A, Konermann A. Increased tooth mobility after fixed orthodontic appliance treatment can be selectively utilized for case refinement via positioner therapy - a pilot study. BMC Oral Health 2020; 20:114. [PMID: 32299416 PMCID: PMC7164254 DOI: 10.1186/s12903-020-01097-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 03/29/2020] [Indexed: 11/13/2022] Open
Abstract
Background Increased tooth mobility persists after fixed orthodontic appliance removal, which is therapeutically utilized for post-treatment finishing with positioners. As such a fine adjustment is only required for selected teeth, the aim of this pilot study was to investigate tooth mobility in vivo on corrected and uncorrected subgroups under positioner therapy. Methods Mobility was measured on upper teeth of 10 patients (mean age 16.8) by applying loadings for 0.1, 1.0 and 10.0 s with a novel device directly after multibracket appliance debonding as much as 2d, 1, 2 and 6 weeks later. Positioners were inserted at day 2. Specimens were divided into Group C (teeth corrected via positioner), Group N (uncorrected teeth adjacent to teeth from group C), and Group U (uncorrected teeth in an anchorage block). Untreated individuals served as controls (n = 10, mean age 22.4). Statistics were performed via Kolmogorov-Smirnov test and Welch’s unequal variances t-test for comparisons between groups. P < 0.05 was considered statistically significant. Results After 1 week, tooth mobility in Group U almost resembled controls (13.0–15.7 N), and reached physiological values after 6 weeks (17.4 N vs. 17.3 N in controls). Group C (9.0–13.4 N) and Group N (9.2–14.7 N) maintained increased mobility after 6 weeks. Tooth mobility was generally higher by reason of long loading durations (10.0 s). Conclusions Positioner therapy can selectively utilized increased tooth mobility upon orthodontic fixed appliance treatment for case refinements. Here, uncorrected teeth in anchorage blocks are not entailed by unwanted side effects and recover after 6 weeks post treatment. Corrected teeth and their neighbors exhibit enhanced mobility even after 6 weeks, which represents a necessity for the proper correction of tooth position, and concurrently arouses the requirement for an adequate retention protocol.
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Affiliation(s)
- L Keilig
- Endowed Professorship for Oral Medical Technology, University of Bonn, Bonn, Germany
| | - J Goedecke
- Endowed Professorship for Oral Medical Technology, University of Bonn, Bonn, Germany
| | - C Bourauel
- Endowed Professorship for Oral Medical Technology, University of Bonn, Bonn, Germany
| | - N Daratsianos
- Department of Orthodontics, University of Bonn, Welschnonnenstr. 17, 53111, Bonn, Germany
| | - C Dirk
- Endowed Professorship for Oral Medical Technology, University of Bonn, Bonn, Germany
| | - A Jäger
- Department of Orthodontics, University of Bonn, Welschnonnenstr. 17, 53111, Bonn, Germany
| | - A Konermann
- Department of Orthodontics, University of Bonn, Welschnonnenstr. 17, 53111, Bonn, Germany.
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Meirelles L, Siqueira R, Garaicoa-Pazmino C, Yu SH, Chan HL, Wang HL. Quantitative tooth mobility evaluation based on intraoral scanner measurements. J Periodontol 2019; 91:202-208. [PMID: 31378924 DOI: 10.1002/jper.19-0282] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 07/18/2019] [Accepted: 07/21/2019] [Indexed: 11/10/2022]
Abstract
BACKGROUND Tooth mobility assessment is subjective and current techniques require the translation of a continuous variable to a categorical variable based on the perception of the examiner. The aim of this study was to evaluate the reliability of a novel technique to assess tooth mobility. METHODS Three experienced periodontists were asked to push tooth #16 into a buccal position to in a typodont model with different mobility (M1-M2). Tooth position was obtained using an intraoral scanner and files were compared in metrology software. Mobility was calculated at three reference points at the cervical (C), middle (M), and occlusal (O) regions of the buccal surface of the tooth to determine the linear deviation in the three axes (x, y, and z). Reliability was determined by intraclass-correlation coefficient, differences between M1 and M2 determined by t test, and the analysis of variance (ANOVA) was used to compare the data at the C-M-O regions. RESULTS Excellent reliability was assessed by Cronbach alpha >0.9 on the x-y-z axes for both mobility tested, except for M1-C X (0.85), M1-M Y (0.89), and M2-M Z (0.89). The correlation between the examiners demonstrated excellent (˃0.90) or good (0.75˃ x ˂0.90) consistency, except for M1-C Y (0.73; examiner 1 to 2) and M1-M X (0.69; examiners 1 to 3). Significant changes were detected in all axes at the three reference points comparing M1 and M2, and a similar proportional change was observed between O-M-C reference points for M1 and M2. CONCLUSION A novel technique to assess tooth mobility based on intraoral scanner measurements provided reliable data in an in vitro experiment.
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Affiliation(s)
- Luiz Meirelles
- Department of Restorative and Prosthetic Dentistry, College of Dentistry, Ohio State University, Columbus, OH
| | - Rafael Siqueira
- Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, MI
| | - Carlos Garaicoa-Pazmino
- Department of Periodontology, School of Dentistry, Oregon Health & Science University, Portland, OR
| | - Shan-Huey Yu
- Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, MI
| | - Hsun-Liang Chan
- Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, MI
| | - Hom-Lay Wang
- Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, MI
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Soltero-Rivera M, Elliott MI, Hast MW, Shetye SS, Castejon-Gonzalez AC, Villamizar-Martinez LA, Stefanovski D, Reiter AM. Fracture Limits of Maxillary Fourth Premolar Teeth in Domestic Dogs Under Applied Forces. Front Vet Sci 2019; 5:339. [PMID: 30761310 PMCID: PMC6364561 DOI: 10.3389/fvets.2018.00339] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Accepted: 12/17/2018] [Indexed: 11/21/2022] Open
Abstract
A cadaveric study was performed to investigate the external mechanical forces required to fracture maxillary fourth premolar teeth in domestic dogs and describe a clinically relevant model of chewing forces placed on functionally important teeth in which fracture patterns are consistent with those defined by the American Veterinary Dental College (AVDC). Twenty-four maxillary fourth premolar teeth were harvested from dog cadavers. Samples consisted of teeth with surrounding alveolar bone potted in polycarbonate cylinders filled with acrylic. The cylinders were held by an aluminum device at an angle of 60° with respect to the ground. An axial compression test was performed, creating a force upon the occluso-palatal aspects of the main cusps of the crowns of the teeth. The highest compressive force prior to failure was considered the maximum force sustained by the teeth. Results showed the mean maximum force (± SD) sustained by the tested teeth at the point of fracture was 1,281 N (± 403 N) at a mean impact angle (± SD) of 59.7° (± 5.2°). The most common fracture type that occurred among all samples was a complicated crown fracture (n = 12), followed by an uncomplicated crown fracture (n = 6), complicated crown-root fracture (n = 5), and uncomplicated crown-root fracture (n = 1). There was no statistically significant correlation between dog breed, age, weight, impact angle, crown height or crown diameter, and the maximum force applied at the point of fracture. The only independent variable that remained significantly associated with maximum force was the crown height to diameter ratio (p = 0.005), suggesting that a decreased ratio increases tooth fracture resistance. The methodology described herein has been successful in creating a pattern of fracture of maxillary fourth premolar teeth consistent with that defined by the AVDC under angled compression at forces within the maximum chewing capability of the average domestic dog.
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Affiliation(s)
- Maria Soltero-Rivera
- Department of Clinical Sciences and Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | | | - Michael W Hast
- The McKay Orthopedic Research Laboratory, University of Pennsylvania, Philadelphia, PA, United States
| | - Snehal S Shetye
- The McKay Orthopedic Research Laboratory, University of Pennsylvania, Philadelphia, PA, United States
| | - Ana C Castejon-Gonzalez
- Department of Clinical Sciences and Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Lenin A Villamizar-Martinez
- Department of Clinical Sciences, North Carolina State University College of Veterinary Medicine, Raleigh, NC, United States
| | - Darko Stefanovski
- Department of Clinical Studies-New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, PA, United States
| | - Alexander M Reiter
- Department of Clinical Sciences and Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, United States
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Knaup TJ, Dirk C, Reimann S, Keilig L, Eschbach M, Korbmacher-Steiner H, Bourauel C. Time-dependent behavior of porcine periodontal ligament: A combined experimental, numeric in-vitro study. Am J Orthod Dentofacial Orthop 2018; 153:97-107. [DOI: 10.1016/j.ajodo.2017.05.034] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Revised: 05/01/2017] [Accepted: 05/01/2017] [Indexed: 10/18/2022]
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Hamanaka R, Yamaoka S, Anh TN, Tominaga JY, Koga Y, Yoshida N. Numeric simulation model for long-term orthodontic tooth movement with contact boundary conditions using the finite element method. Am J Orthod Dentofacial Orthop 2017; 152:601-612. [PMID: 29103438 DOI: 10.1016/j.ajodo.2017.03.021] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 03/01/2017] [Accepted: 03/01/2017] [Indexed: 10/18/2022]
Abstract
INTRODUCTION Although many attempts have been made to simulate orthodontic tooth movement using the finite element method, most were limited to analyses of the initial displacement in the periodontal ligament and were insufficient to evaluate the effect of orthodontic appliances on long-term tooth movement. Numeric simulation of long-term tooth movement was performed in some studies; however, neither the play between the brackets and archwire nor the interproximal contact forces were considered. The objectives of this study were to simulate long-term orthodontic tooth movement with the edgewise appliance by incorporating those contact conditions into the finite element model and to determine the force system when the space is closed with sliding mechanics. METHODS We constructed a 3-dimensional model of maxillary dentition with 0.022-in brackets and 0.019 × 0.025-in archwire. Forces of 100 cN simulating sliding mechanics were applied. The simulation was accomplished on the assumption that bone remodeling correlates with the initial tooth displacement. RESULTS This method could successfully represent the changes in the moment-to-force ratio: the tooth movement pattern during space closure. CONCLUSIONS We developed a novel method that could simulate the long-term orthodontic tooth movement and accurately determine the force system in the course of time by incorporating contact boundary conditions into finite element analysis. It was also suggested that friction is progressively increased during space closure in sliding mechanics.
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Affiliation(s)
- Ryo Hamanaka
- Department of Orthodontics and Dentofacial Orthopedics, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
| | - Satoshi Yamaoka
- Department of Orthodontics and Dentofacial Orthopedics, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Tuan Nguyen Anh
- Department of Orthodontics and Dentofacial Orthopedics, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Jun-Ya Tominaga
- Department of Orthodontics and Dentofacial Orthopedics, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Yoshiyuki Koga
- Department of Orthodontics, Nagasaki University Hospital, Nagasaki, Japan.
| | - Noriaki Yoshida
- Department of Orthodontics and Dentofacial Orthopedics, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
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In vivo determination of tooth mobility after fixed orthodontic appliance therapy with a novel intraoral measurement device. Clin Oral Investig 2016; 21:1283-1289. [DOI: 10.1007/s00784-016-1881-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 06/09/2016] [Indexed: 12/20/2022]
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Sung EH, Kim SJ, Chun YS, Park YC, Yu HS, Lee KJ. Distalization pattern of whole maxillary dentition according to force application points. Korean J Orthod 2015; 45:20-8. [PMID: 25667914 PMCID: PMC4320314 DOI: 10.4041/kjod.2015.45.1.20] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 07/05/2014] [Accepted: 07/21/2014] [Indexed: 12/26/2022] Open
Abstract
Objective The purpose of this study was to observe stress distribution and displacement patterns of the entire maxillary arch with regard to distalizing force vectors applied from interdental miniscrews. Methods A standard three-dimensional finite element model was constructed to simulate the maxillary teeth, periodontal ligament, and alveolar process. The displacement of each tooth was calculated on x, y, and z axes, and the von Mises stress distribution was visualized using color-coded scales. Results A single distalizing force at the archwire level induced lingual inclination of the anterior segment, and slight intrusive distal tipping of the posterior segment. In contrast, force at the high level of the retraction hook resulted in lingual root movement of the anterior segment, and extrusive distal translation of the posterior segment. As the force application point was located posteriorly along the archwire, the likelihood of extrusive lingual inclination of the anterior segment increased, and the vertical component of the force led to intrusion and buccal tipping of the posterior segment. Rotation of the occlusal plane was dependent on the relationship between the line of force and the possible center of resistance of the entire arch. Conclusions Displacement of the entire arch may be dictated by a direct relationship between the center of resistance of the whole arch and the line of action generated between the miniscrews and force application points at the archwire, which makes the total arch movement highly predictable.
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Affiliation(s)
- Eui-Hyang Sung
- Department of Orthodontics, School of Dentistry, Yonsei University, Seoul, Korea
| | - Sung-Jin Kim
- Department of Orthodontics, School of Dentistry, Yonsei University, Seoul, Korea
| | - Youn-Sic Chun
- Division of Orthodontics, Department of Dentistry, Ewha Womans University Medical Center, Seoul, Korea
| | - Young-Chel Park
- Department of Orthodontics, School of Dentistry, Yonsei University, Seoul, Korea
| | - Hyung-Seog Yu
- Department of Orthodontics, School of Dentistry, Yonsei University, Seoul, Korea
| | - Kee-Joon Lee
- Department of Orthodontics, School of Dentistry, Yonsei University, Seoul, Korea
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Kim M, Seol KS, Lee Y, Park J, Kim M, Chun YS. Effects of retraction force and anchorage reinforcement on occlusal force: a model study. Eur J Orthod 2013; 36:563-8. [PMID: 24265465 DOI: 10.1093/ejo/cjt085] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVES The aim of this study was to investigate the effects of retraction force and anchorage reinforcement with orthodontic mini implants on occlusal force. MATERIALS AND METHODS A strain gauge was attached to the palatal surface of the maxillary right first molar on an en masse retraction model. RESULTS Occlusal forces were measured from this model, according to different retraction forces that were generated by elastic chain, under varied compressive forces (simulating masticatory forces). This retraction experiment was then performed again, after using anchorage reinforcement with an orthodontic mini implant. Occlusal force decreased as retraction force increased. The decrease showed a significant difference above 150g of retraction force (P < 0.05) and was more definite under compressive force higher than 150 N (P < 0.001). After anchorage reinforcement with the orthodontic mini implant, however, occlusal force did not significantly decrease with increasing retraction force. Significant differences in occlusal force were noted between the conditions with and without anchorage reinforcement when the applied retraction force was greater than 200g. CONCLUSION Occlusal force tends to decrease during retraction, and this decrease can be prevented by anchorage reinforcement with orthodontic mini implants. LIMITATIONS Further investigation on the actual masticatory process in humans is required for more clear clinical implication.
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Affiliation(s)
- MoonHee Kim
- *Division of Orthodontics, Department of Dentistry, Ewha Womans University Medical Center and Divisions of
| | | | | | - Jiman Park
- ***Prosthodontics, Department of Dentistry, Ewha Womans University School of Medicine, Seoul, Korea
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Goellner M, Berthold C, Holst S, Petschelt A, Wichmann M, Schmitt J. Influence of attachment and bone loss on the mobility of incisors and canine teeth. Acta Odontol Scand 2013; 71:656-63. [PMID: 23145485 DOI: 10.3109/00016357.2012.711488] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE The purpose of this clinical study was to evaluate the correlation between tooth mobility (TM), crown-to-root ratio (CRR) and clinical attachment loss (CAL) in periodontally-compromised participants. MATERIALS AND METHODS While slowly biting on a load cell, the mobility of the upper incisors and canine teeth of 20 volunteers was measured using a photogrammetric measurement technique. An automated software program recorded the force-related three-dimensional TM at 3-N intervals. CAL was assessed clinically and CRR values were assessed radiographically. For each contralateral pair of teeth (central, lateral incisor, canine) and for each main level of force, the Pearson product-moment correlation coefficient between TM and CRR and between TM and CAL was computed. Correlations were considered statistically significant at p < 0.05. RESULTS Statistically significant positive correlations were found between TM and CRR for incisors and canines for each main level of force, whereas canines had the lowest correlation. Statistically significant positive correlations were also found between TM and CAL for the central and lateral incisors at each main level of force. Canines showed no significant correlation between CAL and TM, regardless of force level. CONCLUSION The loss of attachment and bone seem to have more influence on the mobility of incisors than canines.
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Affiliation(s)
- Matthias Goellner
- Dental Clinic 2, Department of Prosthodontics, University Clinic Erlangen, Glueckstr. 11, 91054 Erlangen, Germany.
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Meireles JKSD, Ursi W. Optimization of orthodontic treatment using the Centrex System to retract anterior teeth. Dental Press J Orthod 2012. [DOI: 10.1590/s2176-94512012000400011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
INTRODUCTION: In the end of 90's the adoption of mini-implants as Anchorage allowed a paradigm change influencing even the way of thinking orthodontic mechanics. The overlapping of the specialties of Orthodontics and Implantology started with orthodontic preparations for prosthetic implants insertion, aroused with the use of palatal implants and late with the introduction of mini-implants. The improvement of mini-implants insertion technique with the appearing of self-drilling screws has allowed orthodontists to plan and to place this precious Anchorage piece. Taking into account the versatility of positioning of these screws it was developed a concept that allows the construction of force action lines aiming at optimize the planning and predictability of orthodontic motion. OBJECTIVE: To present some clinical results treatments conduct using Centrex System of orthodontic treatment, approximating the force line action of resistance center of units to be moved. The traced way to its development, previously treated in this journal, will be detailed for better understanding of its functioning.
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Papadopoulou K, Keilig L, Eliades T, Krause R, Jager A, Bourauel C. The time-dependent biomechanical behaviour of the periodontal ligament--an in vitro experimental study in minipig mandibular two-rooted premolars. Eur J Orthod 2011; 36:9-15. [DOI: 10.1093/ejo/cjr134] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Goellner M, Schmitt J, Karl M, Wichmann M, Holst S. Photogrammetric measurement of initial tooth displacement under tensile force. Med Eng Phys 2010; 32:883-8. [PMID: 20619717 DOI: 10.1016/j.medengphy.2010.06.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2009] [Revised: 06/09/2010] [Accepted: 06/10/2010] [Indexed: 11/15/2022]
Abstract
The purpose of this study was to quantitatively measure tooth displacement under low horizontal tensile force (≤18 N) and to test the reproducibility of measurements. Anterior tooth mobility was measured using a photogrammetric measurement technique in 23 periodontally healthy subjects. While slowly increasing the tension on each tooth, an automated software program recorded three-dimensional tooth displacement at 3 N intervals, up to 18 N. Measurements were repeated three-times for each tooth. The vector of absolute tooth mobility in the buccal direction was calculated. Intra-class correlations of the three repeated measurements of each tooth were calculated and ranged between "good" and "optimal". The agreement of measurements was significant (p≤0.05). The analysis of differences between the deviation vectors of contralateral teeth revealed that most differences emerged to be statistically non-significant. The combination of a mechanical loading approach with the optoelectronic system allowed the measurement of three-dimensional tooth mobility in vivo.
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Affiliation(s)
- Matthias Goellner
- Dental Clinic 2, Department of Prosthodontics, University Clinic Erlangen, Glueckstr. 11, 91054 Erlangen, Germany.
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Göllner M, Holst A, Berthold C, Schmitt J, Wichmann M, Holst S. Noncontact intraoral measurement of force-related tooth mobility. Clin Oral Investig 2009; 14:551-7. [DOI: 10.1007/s00784-009-0344-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2009] [Accepted: 09/03/2009] [Indexed: 11/29/2022]
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Bosshardt DD, Bergomi M, Vaglio G, Wiskott A. Regional structural characteristics of bovine periodontal ligament samples and their suitability for biomechanical tests. J Anat 2008; 212:319-29. [PMID: 18304207 DOI: 10.1111/j.1469-7580.2008.00856.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Mechanical testing of the periodontal ligament requires a practical experimental model. Bovine teeth are advantageous in terms of size and availability, but information is lacking as to the anatomy and histology of their periodontium. The aim of this study, therefore, was to characterize the anatomy and histology of the attachment apparatus in fully erupted bovine mandibular first molars. A total of 13 teeth were processed for the production of undecalcified ground sections and decalcified semi-thin sections, for NaOH maceration, and for polarized light microscopy. Histomorphometric measurements relevant to the mechanical behavior of the periodontal ligament included width, number, size and area fraction of blood vessels and fractal analysis of the two hard-soft tissue interfaces. The histological and histomorphometric analyses were performed at four different root depths and at six circumferential locations around the distal and mesial roots. The variety of techniques applied provided a comprehensive view of the tissue architecture of the bovine periodontal ligament. Marked regional variations were observed in width, surface geometry of the two bordering hard tissues (cementum and alveolar bone), structural organization of the principal periodontal ligament connective tissue fibers, size, number and numerical density of blood vessels in the periodontal ligament. No predictable pattern was observed, except for a statistically significant increase in the area fraction of blood vessels from apical to coronal. The periodontal ligament width was up to three times wider in bovine teeth than in human teeth. The fractal analyses were in agreement with the histological observations showing frequent signs of remodeling activity in the alveolar bone - a finding which may be related to the magnitude and direction of occlusal forces in ruminants. Although samples from the apical root portion are not suitable for biomechanical testing, all other levels in the buccal and lingual aspects of the mesial and distal roots may be considered. The bucco-mesial aspect of the distal root appears to be the most suitable location.
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Affiliation(s)
- Dieter D Bosshardt
- Department of Periodontology and Fixed Prosthodontics, School of Dental Medicine, University of Berne, Berne, Switzerland.
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Yoshida N, Jost-Brinkmann PG, Koga Y, Mimaki N, Kobayashi K. Experimental evaluation of initial tooth displacement, center of resistance, and center of rotation under the influence of an orthodontic force. Am J Orthod Dentofacial Orthop 2001; 120:190-7. [PMID: 11500662 DOI: 10.1067/mod.2001.115036] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The purpose of this study was to determine the location of the center of resistance and the center of rotation of the maxillary central incisors under the influence of a single simple force and to investigate related geometric parameters of the teeth and the surrounding periodontal tissues. By measuring the initial displacement of the central incisors with a magnetic sensing system, the location of the center of resistance and the centers of rotation associated with various forces were determined in 3 human subjects. The results show that the location of the center of resistance of the maxillary central incisor depends on the palatal bone level and is at approximately two-thirds of the palatal alveolar bone height, measured from the root apex. A greater moment-to-force ratio is needed for any controlled movement of the maxillary incisors during retraction in patients with reduced palatal alveolar bone height. This study suggests a method for estimating the location of the center of resistance of a tooth.
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Affiliation(s)
- N Yoshida
- Department of Orthodontics, Nagasaki University School of Dentistry, Japan.
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Yoshida N, Koga Y, Saimoto A, Ishimatsu T, Yamada Y, Kobayashi K. Development of a magnetic sensing device for tooth displacement under orthodontic forces. IEEE Trans Biomed Eng 2001; 48:354-60. [PMID: 11327504 DOI: 10.1109/10.914799] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We have developed a system for measuring tooth displacement from orthodontic force. Eight small magnetic sensors and a magnet are combined to measure three-dimensional displacement. Sensors, arranged cubically in the three planes of space, are placed in the mouth and fixed to the posterior teeth by a splint. A magnet is placed in the center of the eight sensors and attached to a front tooth that is subjected to orthodontic force. Sensors detect the magnet's movement as target tooth displacement. The system was designed to achieve displacement resolution of 1 microm. The mean percentage of measurement errors was determined to be less than 1% in a 600-cubic-microm volume from calibration. The system was tested clinically on human teeth. Although the oral environment, with high temperature and humidity, was not agreeable with the sensors, this system was stable and accurate enough for quantitative measurement of tooth displacement. The advantage of this system is the ability to detect tooth trajectories by decomposing displacement into translation and rotation and to determine the position of the center of rotation from these parameters.
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Affiliation(s)
- N Yoshida
- Department of Orthodontics, Nagasaki University School of Dentistry, Japan.
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Matsui S, Caputo AA, Chaconas SJ, Kiyomura H. Center of resistance of anterior arch segment. Am J Orthod Dentofacial Orthop 2000; 118:171-8. [PMID: 10935957 DOI: 10.1067/mod.2000.103774] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
It is important to know the location of the center of resistance (CR) to control tooth movement. In this study, photoelastic techniques were used to determine the center of resistance. The photoelastic model included the anterior 4 maxillary teeth, which were interconnected firmly with 6 mm of space between lateral incisors and canines. Determination of the CR for the anterior arch segment was based on considerations of a wide variety of load conditions that generated the more uniform stresses in the supporting alveolar bone simulant. For the arch having the anterior 4 teeth connected, the CR was located within the mid-sagittal plane, 6-mm apical and 4-mm posterior to a line perpendicular to the occlusal plane from the labial alveolar crest of the central incisor.
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Affiliation(s)
- S Matsui
- Department of Orthodontics, School of Dentistry, Meikai University, Saitama, Japan.
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Hinterkausen M, Bourauel C, Siebers G, Haase A, Drescher D, Nellen B. In vitro analysis of the initial tooth mobility in a novel optomechanical set-up. Med Eng Phys 1998; 20:40-9. [PMID: 9664284 DOI: 10.1016/s1350-4533(97)00042-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
An optomechanical set-up was developed to accurately measure displacement/force curves of the initial tooth mobility in vitro. The system presented is capable of recording all six components of a tooth movement resulting from an applied orthodontic force system, and consists of a laser diode-based optical part and a six degree of freedom mechanical part. Three laser diodes were mounted in orthogonal arrangement on the tooth of a specimen and their light (lambda = 670 nm) was focused on the surfaces of three position sensing detectors. The laser beams thus defined a cartesian rigid body coordinate system and the movements of the tooth could directly be derived from the movements of the laser spots on the surfaces of the optical detectors. The force system was applied and simultaneously measured via a three-dimensional force-torque transducer mounted on a six-axis positioning table. Measuring accuracy of the tooth displacements was in the range of 9.0 microns and 0.022 deg for translations and rotations, respectively. Resolution and accuracy of the mechanical system was approx. 0.02 N for the measurement of forces and 0.5 Nmm for torques. Displacement/force diagrams of the specimen of a swine's mandible are presented, showing the relationships between applied force system and tooth displacement of the lower first premolar. The accuracy reached proved to be sufficient for the verification of numerical (Finite Element) models of the initial tooth mobility.
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Affiliation(s)
- M Hinterkausen
- Poliklinik für Kieferorthopädie, Universität Bonn, Germany
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Siatkowski RE. Continuous arch wire closing loop design, optimization, and verification. Part I. Am J Orthod Dentofacial Orthop 1997; 112:393-402. [PMID: 9345151 DOI: 10.1016/s0889-5406(97)70047-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In Part I, a systematic approach to closing loop design for use in continuous arch wires is presented. The design process uses Castigliano's theorem to derive equations for moment-to-force ratio (M/F) in terms of loop geometry. The equations are used to optimize designs by optimizing M/F to produce tooth movement via translation. Further refinements are performed with finite element simulations of designs. In Part II, predicted results are verified experimentally. The result of this process is a new design, the Opus loop, which is capable of delivering a nonvarying target M/F within the range of 8.0 to 9.1 mm inherently, without adding residual moments via twist or bends (commonly gable bends) anywhere in the arch wire or loop before insertion. The resulting precise force systems delivered with nonvarying M/F can move groups of teeth more accurately to achieve predetermined anteroposterior treatment goals for esthetics and/or stability. In Part II the experimental results show that the loops must be bent accurately to achieve their design potential. The negative impact on M/F of various dimensional changes to the loop design are presented. Experimental data are presented illustrating the improved performance of the new design over standard available designs. Suggested applications of the design for varying anchorage requirements are presented, along with a case report in which rigorous protraction requirements were met.
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Norton LA, Andersen KL, Arenholt-Bindslev D, Andersen L, Melsen B. A methodical study of shape changes in human oral cells perturbed by a simulated orthodontic strain in vitro. Arch Oral Biol 1995; 40:863-72. [PMID: 8651891 DOI: 10.1016/0003-9969(95)00044-p] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Cells are known to alter their shape as a response to physical and chemical changes. Mechanical loads applied to teeth produced cellular perturbations resulting in orthodontic movement. An in vitro model was developed to simulate the in vivo strain of orthodontic movement. Calibrated forces were applied to human periodontal ligament cells and buccal mucosal fibroblasts (controls). A biaxial strain-producing device was used to stretch vital cells growth on flexible polytetrafluorethylene membranes. In addition, a new cell adhesive, Cell Tak, was employed to examine the effect of an adhesive substrate on the cellular response to two known loads. The shape changes of unstrained (control) and strained cells were evaluated by time-lapse telemicroscopy, and plots of time-dependent alterations in area and shape were recorded. The fusiform cells became more rounded over a given time of up to 1400 s. The responses appeared to be independent of cell type, the strain employed, and the presence of cell adhesive. Scanning electron microscopy demonstrated, irrespective of cell type, that the surface of stressed cells produced a striking number of microvilli as compared with the relatively smooth-surfaced controls.
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Affiliation(s)
- L A Norton
- Department of Orthodontics, University of Connecticut School of Dental Medicine, Farmington 06030, USA
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