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1
Shank, Stephanie Brooke. "Bone Damage Associated with Orthodontic Miniscrew Implants." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1299685868.
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Busciglio, Dana. "Effect of thread design of orthodontic miniscrew implants on stress generation using photoelastic analysis." Thesis, NSUWorks, 2011. https://nsuworks.nova.edu/hpd_cdm_stuetd/34.
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A thesis submitted to the College of Dental Medicine of Nova Southeastern University of the degree of Master of Science in Dentistry.
Objectives. The purpose of this study was to determine the effect of pitch and thread depth of orthodontic miniscrew implants(MSI's) on stress generation. Methods. Quasi-three dimensional photoelastic models were created with MSI's embedded and then loaded with 60 and 104 grams respectively and evaluated under a full field reflection polariscope. The control MSI's (1.0mm pitch / 0.25mm thread depth) were compared to 3 experimental groups (n=10) which varied with only one design characteristic: Group 1 (0.75mm pitch), Group 2 (1.25mm pitch) and Group 3 (0.40 thread depth). The maximum shear stress (τmax) was calculated at 5 predetermined and standardized points. A two-way ANOVA was conducted to compare the means of τmax followed by a Tukey's post hoc (p<0.05). Results. No statistical differences were found for τmax between the control group and each of the 3 experimental groups except at point 4. At point 4, the control group was higher by an average of 5.05 and 7.1 MPa for the 60 and 104 gram loads respectively (p<0.05). No statistically significant differences were found for points 1, 2, and 5 for the 60 gram load and for points 1, 2, 3, and 5 for the 104 gram load. The mean τ max from highest to lowest was located at points 5<1< 2<4 <3 in both the 60 and 104 load steps. The variability in τmax at point 4 may have been due to its proximity to the neutral zone of the present loading conditions. Conclusions. As the orthodontic load was increased, maximum shear stress also increased for each of the four MSI designs used in this study. The results of this study suggest that, within limits, variation of pitch and thread depth of MSI's may not have a significant influence on the stress generation when loaded for orthodontic purposes. Photoelastic analysis has shown to be a viable option to evaluate mechanical properties of MSI'S.
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Pollei, Jason Karl Ko Ching-Chang. "Finite Element Analysis of miniscrew placement in maxillary alveolar bone with varied angulation and material type." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2009. http://dc.lib.unc.edu/u?/etd,2417.
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Thesis (M.S.)--University of North Carolina at Chapel Hill, 2009.<br>Title from electronic title page (viewed Sep. 3, 2009). "... in partial fulfillment of the requirements for the degree of Master of Science in the School of Dentistry Orthodontics." Discipline: Orthodontics; Department/School: Dentistry.
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Jackfert, Lindsay. "A comparison of bacterial adherence on standard orthodontic brackets and titanium miniscrew implants an in vivo and in vitro study /." Morgantown, W. Va. : [West Virginia University Libraries], 2008. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5608.
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Thesis (M.S.)--West Virginia University, 2008.<br>Title from document title page. Document formatted into pages; contains ix, 98 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 66-70).
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Rothstein, Ira. "Effects of synthetic cortical bone thickness and force vector application on temporary anchorage device pull-out strength as related to clinical perspectives of practicing orthodontists." Thesis, NSUWorks, 2011. https://nsuworks.nova.edu/hpd_cdm_stuetd/56.
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December 2011.
A thesis submitted to the College of Dental Medicine of Nova Southeastern University of the degree of Master of Science in Dentistry.
Background: Temporary anchorage devices (TADs) provide a versatile means by which orthodontic anchorage can be established without the need for patient compliance and complex force systems. Their use is predicated on their ability to remain stable throughout the course of treatment in which they are needed. This has been shown to be the result of "primary stability" which is achieved through mechanical interlocking of the screw threads with the surrounding bone immediately upon placement. Therefore, evaluating the factors that can either enhance or detract from the primary stability of TADs can serve to improve the predictability of their success. Objectives: The objectives of this study were to describe how variations in synthetic cortical bone thickness and the angle of force applied in relation to the long axis of TADs affects their stability in terms of pull-out strength, and to ascertain the perspectives of practicing orthodontists in the state of Florida on their experiences with temporary anchorage devices with regards to success and failure. Methods: For the bench top study, 90 1.5x8mm long neck Orthotechnology Spider Screws were randomly allocated to 9 groups of 10 TADs each. The 9 groups were established based on both the thickness of synthetic cortical bone (1.0, 1.5, and 2.0mm) and the angle of force vector applied relative to the long axis of the TADs (45, 90, and 1800). Pull-out testing was carried out by applying a force to the TADs via a universal testing machine (Instron, Canton, MA) at a rate of 2.0mm/minute. Real-time graphical and digital readings were recorded, with the forces being recorded in Newtons (N). Each miniscrew was subjected to the pull force until peak force values were obtained. For the 450 and 1800 tests, the force registered at the time-point of pull-out, or screw head movement of 1.5mm within the synthetic bone blocks. The determination of 1.5mm of movement was made due the dramatically erratic deflection observed by the digital and graphical readouts at precisely this point. For the survey portion of this study, A customized survey was developed for this study. The survey was composed of 12 questions, some of which were obtained from a questionnaire that was created by Buschang et al.54 The additional questions were devised by the members of this research project, with the aim of answering questions regarding the clinical experiences that practicing orthodontists experienced with TADs. Results: For the bench top study: Implants placed in 2.0mm of synthetic cortical bone and pulled at an angle of 1800 had the highest pull-out strength among all groups (258.38N), while those placed in 1.0mm of synthetic cortical bone and pulled at an angle of 900 exhibited the lowest (67.11N). When evaluated separately, a cortical bone thickness of 2.0 mm displayed the highest pull-out forces for the three angles of force application, and 1800 angle of force displayed the highest-pull-out forces for the three cortical bone thicknesses. Conversely, 1.0mm of cortical bone thickness displayed the lowest pull-out forces for the three angles of force application, and 900 angle of force displayed the highest-pull-out forces for the three cortical bone thicknesses. For the survey: The most important factor associated with TAD failure was cited as placement location by 45.7% (n=16) of respondents, while root proximity was cited as the least important factor by 35.3% (n=12) of respondents. For the site from which practitioners indicated that they experience the greatest success, 81.8% cited the palate, while 51.9% responded that they experience the highest failure rates for the posterior maxilla (distal to the cuspids). Conclusions: A synthetic cortical bone thickness of 2mm and pull forces applied parallel to the long axis of TADs resulted in the greatest resistance to pull-out.
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Alharbi, Fahad. "An investigation of the effectiveness of miniscrews in orthodontics." Thesis, University of Dundee, 2016. https://discovery.dundee.ac.uk/en/studentTheses/2fc1207d-dbc3-43cb-b487-d19115dd346b.
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Aims: The aims of this study were to systematically review the evidence on miniscrews failure rate, their effectiveness in anchorage reinforcement, to assess the quality of reporting clinical trials in orthodontic literature in an observational study, to audit their use in the UK and to compare the anchorage effectiveness when measured against headgear and transpalatal arch in a randomised clinical trial. Methods: In two systematic reviews, databases were searched, data was extracted, the risk of bias was assessed and meta-analyses were performed when appropriate. In the observational study, clinical trials reports that were published in four major journals from 2008-2012 were identified and assessed against CONSORT checklist to evaluate the quality of reporting. The audit was a prospective multi-centre audit investigating the use of miniscrews in the UK. In a randomised clinical trial, orthodontic patients were randomly allocated into three groups (headgear, miniscrews or transpalatal arch). Digital models were measured to assess the anchorage loss. Results: The first systematic review and meta-analysis demonstrated that the failure rate of miniscrews was 14.1%(95% CI, 12-16.5). The data were obtained from 43 studies (16 clinical trials and 27 cohort studies). The second systematic review showed that overall mean difference in molar movement was 2.206mm in favour of miniscrews ( MD = - 2.20; 95% - 1.21 to -3.19) when compared with conventional anchorage methods. The data were obtained from seven clinical trials. The observational study assessed the reporting quality of 151 clinical trials and showed that clinical trials reports represented less than 5% of the articles published in four major journal and their reporting was suboptimal. The audit showed that none of the agreed standards were met except for infection/inflammation around the screw resulting in loss or removal in 5.6% of the cases while the standards were being below 20%. The miniscrew failure rate in this audit was 24.2%. The total number of placed miniscrews was 1072. The randomised clinical trial revealed no difference between headgear, transpalatal arch or miniscrews in regards to anchorage effectiveness. 51% of study models required to measure the primary outcome were missing. Conclusion: Based on the two systematic reviews, miniscrews have a modest failure rate and they are useful clinically to reinforce anchorage. Reporting clinical trials is suboptimal in orthodontic literature. The only item that met audit standards was failure due to infection/inflammation. The rest of the audit standards were not met. Recommendations are made to address these issues. In the clinical trial, no difference in anchorage effectiveness between headgear, transpalatal arch or miniscrews was found. The findings of this clinical trial should be interpreted with caution due to the missing data.
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Lee, Jim Ming-An. "Effect of Mini-implant Diameters on Primary Stability and Viscoelastic Migration of Mini-implants under Orthodontic Loading." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1365079269.
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Gigliotti, Mariana Pracucio. "Influência da proximidade entre o mini-implante e as raízes dentárias sobre o grau de estabilidade." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/25/25134/tde-29052009-111711/.
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O objetivo deste trabalho foi avaliar a influencia da proximidade entre miniimplantes autoperfurantes e as raizes dentarias sobre a estabilidade destes dispositivos de ancoragem. A amostra consistiu de 40 mini-implantes inseridos entre as raizes do primeiro molar e segundo pre-molar superiores de 21 pacientes, como recurso de ancoragem para retracao anterior. A largura do septo no local de insercao (LSI) e a menor distancia da cabeca do mini-implante a raiz dentaria (MDR) foram mensuradas nas 40 radiografias pos-cirurgicas. Sob este aspecto, os miniimplantes foram divididos em duas categorias de grupos: de acordo com a largura do septo no local de insercao, grupos G1L (LSI3mm) e G2L (LSI>3mm), e de acordo com a proximidade do mini-implante a raiz adjacente, grupos G1P (MDR0mm) e G2P (MDR>0mm). A estabilidade dos mini-implantes foi avaliada mensalmente pela quantificacao do grau de mobilidade, e a partir desta variavel foi calculada a proporcao de sucesso. Tambem foi avaliada a influencia das seguintes variaveis sobre o grau de estabilidade: caracteristica do tecido mole no local de insercao, o grau de sensibilidade, a quantidade de placa, a altura de insercao e o periodo de observacao. As duas categorias de grupos foram comparadas quanto ao grau de mobilidade e proporcao de sucesso por meio do teste de Mann-Whitney e do teste Exato de Fisher, respectivamente. Adicionalmente, avaliou-se a influencia das demais variaveis sobre a estabilidade deste sistema de ancoragem atraves do teste t e do teste do Qui-quadrado. Os resultados obtidos demonstraram que não houve diferenca estatisticamente significante para o grau de mobilidade e proporção de sucesso entre os mini-implantes inseridos em septos do grupo G1L e G2L. A proximidade entre os mini-implantes avaliados e as raizes dentarias adjacentes (grupos G1P e G2P) tambem nao influenciou na estabilidade e proporcao de sucesso deste sistema de ancoragem. A proporcao de sucesso total encontrada foi de 90% e nenhuma variavel demonstrou estar relacionada ao insucesso dos miniimplantes. No entanto, observou-se maior sensibilidade nos pacientes cujos miniimplantes apresentavam mobilidade, e que a falha destes dispositivos de ancoragem ocorria logo apos sua insercao.<br>The purpose of this study was to evaluate the influence of the proximity between self-drilling miniscrews and dental roots on the stability degree. The sample consisted of 40 miniscrews inserted in the interradicular septum between maxillary second premolars and first molars to provide skeletal anchorage for anterior retraction. The forty post-surgical radiographs were used to measure the septum width in the insertion site (SWI) and the smallest distance between miniscrew head and dental root (SDR). In this regard, the miniscrews were divided in two categories of groups: according to the septum width in the insertion site, groups G1W (SWI 3mm) and G2W (SWI>3 mm), and according to the miniscrew dental root proximity, groups G1P (SDR0mm) and G2P (SDR>0mm). The mobility degree (MD) was monthly quantified to determine miniscrew stability, and the success rate of these devices was calculated. This study also evaluated the influence of following variables on the stability degree: soft tissue characteristics in the insertion site (attached gingiva, mucogingival junction and alveolar mucosa), sensitivity degree during miniscrew load, plaque amount around miniscrew, insertion height, and total evaluation period. All the groups were compared regarding mobility degree and success rate using t test and Fisher exact test, respectively. The results showed no significant difference in mobility degree and success rate between groups G1W and G2W. The miniscrew dental root proximity did not influence the stability and success rate of this anchorage system when G1P and G2P were compared. The total success rate found was 90% and no variable was associated with the miniscrew failure. Nevertheless, the results showed that greater patient sensitivity degree was associated to the miniscrews mobility and the failure of these anchorage devices happened in a short time after their insertion.
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Gritsch, Kerstin. "Biointégration de minivis d’ancrage orthodontique : évaluation clinique et analyse de l’interface biomatériau-tissu osseux en histomorphométrie et en microtomographie." Thesis, Lyon 1, 2010. http://www.theses.fr/2010LYO10354.
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Depuis une dizaine d’années, l’essor des minivis d’ancrage orthodontique a été grandissant jusqu’à devenir, aujourd’hui, un outil incontournable dans l’arsenal thérapeutique de l’orthodontiste. Très peu d’études ont été publiées quant à la nature de la réponse tissulaire face à l’insertion et la mise en charge de ces minivis. De plus, une partie des patients concernés par l’orthodontie étant des adolescents, il serait intéressant de savoir si le tissu osseux en croissance est propice à l’utilisation de ces dispositifs. L’influence de la nature du matériau sur cette réaction tissulaire reste également à définir. L’objectif de cette étude a été d’évaluer la biointégration de deux systèmes de minivis orthodontiques présents sur le marché, l’un en acier chirurgical et l’autre en titane-aluminium-vanadium, en conduisant une analyse clinique, histomorphométrique et microtomographique chez le porc en croissance. Les résultats ont montré que la réponse osseuse se caractérise, dans un os en croissance peu compact, par un épaississement des travées osseuses au contact des dispositifs, probablement pour résister à la contrainte locale. Le tissu osseux en croissance permet la biointégration des minivis d’ancrage orthodontique, mais le taux de succès relativement faible observé implique l’adaptation des protocoles cliniques par une analyse préalable du ratio os trabéculaire/os cortical, une augmentation du délai avant mise en charge, et l’application de forces légères. La réponse tissulaire est similaire, quel que soit le système étudié. L’acier chirurgical, grandement utilisé en orthopédie, présente donc un intérêt en orthopédie dento-faciale, dans une indication temporaire<br>The miniscrew implants are increasingly used over the last decade in orthodontics and gradually replacing the use of extraoral forces because of their greater efficiency and because their effectiveness is not subject to patient compliance. Few studies seeking to understand the response to orthodontic anchorage devices at bone-tissue interface have been published over the last ten years. Despite the large use of miniscrews in teenagers, very few have included young subjects in their protocol. Furthermore, despite the use of stainless steel miniscrew implants, no studies have investigated biointegration of such devices. The aim of the present study was to evaluate tissue response to immediately loaded miniscrew implants (of Ti6Al4V and of stainless steel) in growing pigs in order to answer to the following questions: Is it possible to implant and load miniscrew implants in a growing bone? Does stainless steel devices present the same biointegration than titanium devices? A clinical evaluation, and histomorphometrical and micro-CT analyses were performed. Results showed that the growing bone seems compatible with the orthodontic anchorage. In the growing pig with low bone density areas, the trabecular thickness increase appears as the bone response to withstand the local strains induced by loaded orthodontic miniscrews. Stainless steel devices presented similar behavior to the Ti6Al4V devices in pigs. This study showed the possibility to place stainless steel miniscrew implants for orthodontic anchorage in growing models
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Liao, Joung Lin, and 廖炯琳. "Treatment Effects of Miniscrew Anchorage in Patients with Bimaxillary Protrusion: A Comparison of Various Miniscrew Setups." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/01768898015632473592.
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碩士<br>長庚大學<br>顱顏口腔醫學研究所<br>97<br>ABSTRACT
Introduction: The aim of this retrospective study was to compare treatment effects of various miniscrew anchorage setups for correction of bimaxillary protrusion. The influence of facial divergency on the miniscrew effects was also investigated.
Methods: The sample consisted of 100 adult patients with Angle Class I or Class II bimaxillary protrusion who received extraction treatment and were divided into 4 groups according to the anchorage setups. Group 1 (n=25) received traditional anchorage preparation without miniscrews; group 2 (n=25) received two upper posterior miniscrews; group 3 (n=25) received two upper posterior and one or two anterior miniscrews; group 4 (n=25) received two upper posterior, two lower posterior and one or two anterior miniscrews. Pretreatment and posttreatment lateral cephalograms were superimposed. One-way ANOVA and Kruskal-Wallis tests were used to compare the treatment changes among the 4 groups.
Results: Retraction of upper incisors was greater in groups 2, 3, and 4 than in group 1 (△U1-H: -4.8±2.9 mm vs. -8.9±2.9 mm, -7.4±1.7 mm, and -7.5±3.1 mm, p < 0.01). There was no significant difference in the upper molar horizontal anchorage loss among the 4 groups (△U6-H: 1.8±2.0 mm vs. 0.6±4.3 mm vs. 0.8±1.8 mm vs. 0.1±3.8 mm, p > 0.05). In hyperdivergent patients, groups 3 and 4 showed upward movement of Pogonion (△Pg-V: -0.8 and -1.2 mm, respectively), while group 2 showed downward movement instead (△Pg-V: 1.0 mm) (p < 0.05).
Conclusions: In patients with bimaxillary protrusion, posterior miniscrews provided maximal retraction of upper anterior teeth. In hyperdivergent patients, combined use of posterior and anterior miniscrews provided favorable vertical control with counterclockwise mandibular rotation and facial height reduction.
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Deboutteville, Lisandro Sobral Delamare. "Iatrogenias resultantes da inserçāo de mini-implantes." Master's thesis, 2017. http://hdl.handle.net/10284/6116.
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Com o intuito de facilitar e possibilitar uma atuação clinica mais tranquila na
instalação desses dispositivos, procurou-se sintetizar nesta revisāo bibliográfica
algumas das principais iatrogenias decorrentes desses procedimentos assim como certas
manobras e locais que podem auxiliar na diminuição de tais ocorrências.
Perfuraçāo do seio maxilar, trauma radicular, fratura do mini-implante,
mucosites/peri-implantites, deslize do mini-implante além de injúrias ao feixe vasculonervoso
foram as principais iatrogenias encontradas na literatura. Essa pesquisa
permitiu a tomada de conhecimento de alguns procedimentos importantes, para que as
iatrogenias nāo se intensifiquem, como: a inclinaçāo do dispositivo instalado, a
realizaçāo de pre-perfurações, a preferência da instalação do dispositivo em gengiva
queratinizadas, as localizações mais seguras para as instalações dos dispositivos de
ancoragem temporária entre raízes além de algumas técnicas mais atuais de instalação
extra-alveolar desses dispositivos.<br>In order to facilitate and facilitate and make possible a quieter clinical
performance in the installation of these devices, we tried to synthesize in this
bibliographic review some of the main iatrogenies resulting from these procedures as
well as certain maneuvers and places that can help in the reduction of such occurrences.
Maxillary sinus perforation, radicular trauma, mini-implant fracture, mucositis/
perimplantites, mini-implant slide and injuries to the vascular-nervous bundle were the
main iatrogenic factors found in the literature. This research allowed the knowledge of
some important procedures to prevent iatrogenies from intensifying, such as: inclination
of the installed device, the accomplishment of pre-perforations, the preference of
installing the device in keratinized gingiva, the safest locations for the installation of
DAT(s) between roots, and some more current techniques for extra-cellular installation
of these devices.
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Tseng, Yu-Chuan, and 曾于娟. "The research of mechanical properties of miniscrew implant." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/3m99t7.
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博士<br>高雄醫學大學<br>牙醫學系博士班<br>105<br>Purpose: The purpose of this study is to use resonance frequency (RF) analysis to investigate the correlation of different mechanical properties of temporary anchorage devices (TADs) and the outcomes of clinical application.
Materials and Methods:
Part I. The study of mechanical properties of TADs in artificial bone.
(1) Interradicular area: Thirty TADs (diameter, 1.5 mm; length, 8 mm) of the three brands (Type A, B, and C) were manually inserted 7 mm into synthetic bone without pilot drilling. The insertion torque (IT), resonance frequency (RF), and removal torque (RT) were measured in both vertical and horizontal directions.
(2) Infrazygomatic area: Thirty TADs (diameter: 2 mm; length 12 mm) of the three brands (Type A, B, and C) were manually inserted 7 mm into synthetic bone without pilot drilling. The IT, RF, and RT were measured in both 900 and 450 directions.
(3) Palatal area: Twenty-seven TADs (diameter, 2 mm; length, 7 mm) of the three brands (Type A, B, and C) were manually inserted 3-, 4-, and 5-mm into synthetic bone without pilot drilling. The IT, RF and pullout strength (PS) were measured.
(4) Buccal shelf area: Thirty TADs (diameter, 2 mm; length, 10 mm) of the three brands (Type A, B, and C) were manually inserted 7 mm into synthetic bone without pilot drilling. The IT, RF, horizontal pullout strength (HPS), and gripping volume (GV) were measured.
Statistic methods: One-way analysis of variance and Spearman’s rank correlation coefficient tests were used for intergroup and intragroup comparisons, respectively.
Part II. Assessment of TADs stability in the clinical application by resonance frequency analysis
A total of 68 patients were inserted 66 TADs (2.0 x 12 mm) in the buccal shelf (BS) and 38 TADs (1.5 x 8 mm) in the interradicular (IR) sites. Resonance frequency was measured at the time-interval 〔immediate post-placement (T0); 3 weeks (T3); 6 weeks (T6); 9 weeks (T9); 12 weeks (T12) and 15 weeks (T15)〕. A linear mixed-effect model was fitted to the change in RF value.
Results:
Part I. The study of mechanical properties of TADs in artificial bone.
(1) Interradicular area: Type A exhibited the lowest inner/outer diameter ratio and the widest apical facing angle, leading to the lowest IT and a higher RF values. However, no significant correlations in the IT, RF, and RT were observed among the three groups.
(2) Infrazygomatic area: In the 900 tests, Type C (IT, RF, and RT) were significantly higher than those of Type A. In the 450 test, the RFs of Type C was significantly higher than those of Type A and B. In the both of 900 and 450 tests, Type C exhibited the highest mechanical strengths (IT, RF, and RT) among the three types of TADs. However, Type C exhibited no significant correlation in the intragroup comparisons.
(3) Palatal area: IT of Types C and B were significantly higher than Type A in the implantation depths (5- and 4-mm). However, Type A had a largest PS at the implantation depths (5- and 4-mm). In the implantation depths (3-mm), PS was no difference among the 3 brands. The RF of Type A was significantly lower than that of Types C and Type B.
(4) Buccal shelf area: No significant difference was found in the RF analysis among the three types of TADs. In the HPS test, Type C was significantly larger than both Type B and Type A. In the GV measurement, Type C was significantly larger than Type B and Type A. The mechanical strengths (IT, RF, and HPS) of the TADs corresponded to the order and values of GV (Type C > Type B > Type A).
Part II. Assessment of TADs stability in the clinical application by resonance frequency analysis
Compared to the BS group, the IR group showed significantly lower RF values at the right side (from T0 to T12) and left side (from T0 to T6). Both of IR and BS groups, RFs were significantly decreased at the each time-interval.
Conclusions:
(1) Interradicular area: The detailed dimensions of TADs, including the inner diameter, outer diameter, inner/outer diameter ratio, thread pitch, thread depth, and apical as well as coronal face angles, are critical factors affecting their mechanical strength.
(2) Infrazygomatic area: In the 900 and 450 tests, Type C exhibited the highest mechanical strengths among the three types of TADs.
(3) Palatal area: For the implantation depth (ID) 3, 4, 5 mm, the PS was no significant difference was identified among the three brands. In the implantation depths (3-mm), RF of Type A was significantly lower than that of Types C and Type B.
(4) Buccal shelf area: A trend that larger GVs indicate greater mechanical strengths (IT, RF, and HPS) of TADs was observed.
(5) Clinical application: The RF of TADs was significantly lower in the IR group than BS group. Once applying the load, the RF of both groups were significantly decreased.
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Chen, Shih-Hsuan, and 陳式萱. "Tissue Response After Miniscrew Insertion in Orthodontic Treatment." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/65893581961074297951.
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碩士<br>臺灣大學<br>臨床牙醫學研究所<br>95<br>Anchorage control is important in orthodontic treatment. Orthodontic implants, including miniscrews and miniplates, have drawn attention in recent years for values providing absolute anchorage to achieve diverse treatment goals. However, there are potential problems of damaging adjacent roots and their consequences during miniscrew insertion into alveolar regions. Therefore, miniscrew/root contact and the possible tissue response, including root repair, were investigated histologically in current study. Furthermore, whether complete soft tissue coverage of miniscrews would affect the miniscrew performance was also investigated.
Two mongrel dogs were used. In experiment I, 12 miniscrews were surgically placed in the mandible. Among them, 4 miniscrews (experiment group) were placed with intentional root contact and were then retained for different time durations, 4 (control group 1) were also placed with intentional root contact but were removed immediately after insertion, and the rest 4 (control group 2) were placed without root contact and were retained for the same time durations as in experiment group. In experiment II, 2 miniscrews were placed in the maxilla to investigate the tissue response around the miniscrews and the adjacent roots when the teeth were under orthodontic force. One miniscrew of experiment group was placed with intentional root contact with upper third premolar, and 1 of control group was placed without root contact at the contralateral side. After extraction of upper second premolars , third premolars were then protracted with Ni-Ti coil spring attached to canines during week 3 to week 15. This animal was sacrificed after 24 weeks of experiment. In experiment III, 10 miniscrews were placed with intentional root contacts; half of them covered with gingival flap after insertion, and half of them kept exposed. The animal was sacrificed after 18 weeks and the removal torque of the miniscrews were measured at that time.
Results: (1) The roots with miniscrew damage showed significant inflammation response of surrounding tissue. (2) Root resorption was observed occasionally even if the miniscrews did not contact with the roots directly. This kind of root resorption might be seen as soon as three weeks following miniscrew insertion. (3) Root repair was noted with cementoblasts lining along the resorption surface, which could be seen three weeks following miniscrew insertion. Alveolar bone filled into the lesion when the root damage was large so that the contour of alveolar bone followed that of the damaged root, with the width of periodontal ligament space kept constant. (4) Miniscrews with clinical success were largely those which had no direct contact with adjacent roots, showing little inflammation response in surrounding tissue and some extent of direct bone contact around the miniscrews. On the contrary, most of the failed miniscrews were those which had direct contact with adjacent roots, exhibiting severe tissue inflammation and being covered with thick layers of soft tissue. Failure of miniscrews could be seen as soon as three weeks after insertion. (5) There was no statistically significant relation between the soft tissue coverage of screw head and removal torque according to Mann-Whitney test and Kruskal-Wallis test.
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Wang, Ya-Ting, and 王亞婷. "Surface treatment of 316L stainless steel orthodontic miniscrew." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/18286261478277439705.
Full textAbstract:
碩士<br>國立臺灣大學<br>臨床牙醫學研究所<br>99<br>316L stainless steel orthodontic miniscrews were quite popular in clinical orthodontics, especially in Taiwan. However, the success rate was not good as titanium alloy. We try to improve it by making osseointergration happened. In other words, our research goal was to do some surface modification of 316L stainless steel without changing its properties. The study was divided into two parts:
Part I: we learned the pros and cons of physical vapor deposition（PVD）and sol-gel method from literature review. Ti or TiO2 were coated on 316L stainless steel orthodontic miniscrews either by PVD or sol-gel method, which was supported by manufactory. After analyzing these products, we chose PVD for further investigation because of minimum or no change of the substrate.
Part II：Ti or TiO2 thin films were coated on 316L stainless steel sheet by electron beam evaporation. Then, we used FE-SEM（Field Emission Scanning Electron Microscope） and atomic force microscope（AFM）for analysis. It was found that specimen had austenite grains and grain boundary. The surface roughness was 61 ± 14.3 nm. Thin films attached on the rough surface, but the grooves caused by grain boundary were not filled in completely. There were also some gap between thin film and substrate. After being cut and polished, some film peeled off. However, grains produced by this technique could be small as 15 nm. With the same evaporation source, the higher deposition rate made the grain size larger. The surface roughness was greater, too. Furthermore, we also confirmed that no change in the surface roughness after coating.
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Wei, Ming-Wei, and 魏明偉. "Evaluation of gender difference at orthodontic miniscrew placement sites in mandible: a CBCT study." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/90362904613870175379.
Full textAbstract:
碩士<br>高雄醫學大學<br>牙醫學研究所<br>100<br>Purpose: The purpose of this study is to evaluate gender difference in mandibular bone density,
cortical bone thickness and buccal shelf inclination through three-dimensional images captured by
cone-beam computer tomography(CBCT). As the reference for further orthodontic miniscrews
placement.
Material and method: CBCT images were obtained by I-CAT CBCT image device from 36 males
and 34 females aged from 18 to 40 years old. Mandibular bone density and cortical bone thickness
were measured in 4 sites bilaterally, and buccal shelf inclination was measured in two sites . Inter-
gender and intra-class comparisons were made to distinguish the differences of the acquired data.
Result: Bone density of female showed greater bone density at almost all sites without statistically
significant except left retromolar area (p=0.0067). Intra-class comparison show an increased
tendency of bone density from anterior measuring sites to posterior sites, and significant lower bone
density in retromolar area. Cortical thickness ranges from1.4 to 4.4 mm; more than the minimal
requirement for miniscrews initial stability. And cortical thickness of 3 sites show significant greater
in male than female. For the buccal shelf inclination, both gender measurements showed an increase
tendency from anterior to posterior buccal shelf. The buccal shelf inclination also showed
significant greater in female than male in the measuring site between second molar and third molar
area.
Conclusion: No signigicant difference in bone density by sex except left retromolar area, and
cortical thickness is significant greater in male than female. Buccal shelf inclination is greater in
female than in male indicated relating easier miniscrews placement in female than in male.
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HSIN, CHANG MIN, and 張民欣. "The character of using miniscrew anchorage in the apical root resorption of maxillary incisors." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/55796572048441486940.
Full textAbstract:
碩士<br>長庚大學<br>顱顏口腔醫學研究所<br>95<br>Abstract
Purposes and null hypotheses: The purposes of this study were to study the character of using miniscrew anchorage in the apical root resorption of maxillary incisors, and to explore the possible factors predisposing to the apical root resorption in cases miniscrew anchorage is used for the en masse maxillary anterior retraction-and-intrusion. The null hypotheses were first the apical root resorption of en masse maxillary anterior retraction-and-intrusion with miniscrew anchorage has no difference from that without miniscrew anchorage, and second the dentofacial deformity, direction and extent of tooth movement, and treatment duration are not predisposing factors to the apical root resorption of maxillary incisors when miniscrew anchorage is used for the en masse maxillary anterior retraction-and-intrusion.
Material and methods: Sixty-six adult patients with maxillary protrusion were included in this study. In which, 30 patients were treated with miniscrew anchorage and extraction of maxillary first premolars (Group-I), another 16 patients were treated with miniscrew anchorage but without any teeth extraction except third molars in some cases (Group-II), and the other 20 patients were treated with extraction of maxillary first premolars (Group-III). For each patient, periapical films of the maxillary incisors and lateral cephalometric radiographs were taken before (T1) and after treatment (T2). The radiographs were scanned into computer and calibrated and measured in 1:1 ratio under the Image J measurement program for (1) the apical root resorption of the maxillary central and lateral incisors between T1 to T2, (2) the amount of en masse maxillary anterior retraction-and-intrusion between T1 to T2, (3) the T1 upper incisor angle, SNA, SNB, and ANB angle. The inter-group differences were analyzed by ANOVA and independent t-test, and the correlations were analyzed by Pearson correlation analysis.
Results: The apical root resorption of the three groups ranged from 12.5% to 20.5% or 1.9 mm to 2.7 mm of the original root length. The Group-I had significantly the most severity of intermaxillary discrepancy, greatest amount of anterior retraction at the incisor tip and root apex, and longest duration of treatment. The apical root resorption of the maxillary lateral incisors in Group-I was significantly greater than those of Group-II and –III. However, due to the varied values of standard deviation, the apical root resorption of the maxillary central incisors was not significantly different among groups. The first hypothesis was rejected due to greater apical root resorption of lateral incisors in Group-I. The apical root resorption of the maxillary central or lateral incisors in the patients who had miniscrews (Group-I combined with Group-II) was significantly correlated to the duration of treatment, amount of anterior retraction, pre-treatment severity of upper incisor proclination, mandibular retrognathism, and intermaxillary discrepancy and the second null hypothesis was rejected.
Conclusion: Using miniscrew anchorage for the en masse maxillary retraction-and-intrusion could be a contributing character to the more apical root resorption, especially to the maxillary lateral incisors and in individual who is vulnerable to apical root resorption, and who has severer intermaxillary discrepancy and needs large amount of anterior retraction and longer duration of treatment.
Key words: apical root resorption, miniscrew
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PEPLA, ERLIND, and Massimo GALLI. "TECNICHE CHIRURGICHE DI ANCORAGGIO TEMPORANEO, SURGICAL TECNIQUE OF TEMPORARY ANCHORAGE DEVICES." Doctoral thesis, 2016. http://hdl.handle.net/11573/892074.
Full textAbstract:
La ricerca nel campo della medicina rende giorno dopo giorno passi importanti verso nuove frontiere. In odontoiatria, molti progressi sono stati compiuti negli ultimi decenni, in medici infatti spinti dalla necessità di realizzare le terapie che erano sempre più avanzati, valido ed affidabile nel tempo hanno adottato tecniche per tener conto delle numerose ed elevate esigenze del paziente, come ad come importanti aspettative estetiche, il comfort durante la terapia (per non sottovalutare l'aspetto psicologico dei pazienti che possono influenzare le relazioni sociali nella loro quotidiana).
La domanda di trattamento ortodontico da parte degli adulti è aumentata negli ultimi anni. La popolazione adulta presenta spesso la riduzione dei parodontale di supporto del tessuto e diversi obiettivi di trattamento rispetto alla popolazione pediatrica e adolescenziale.
Il compromesso biomeccanico per poter rispondere più semplicemente a questa doppia componente è l'uso di dispositivi di ancoraggio semplici ed efficaci: i TADS (dall'inglese temporanee ancoraggio Devices).
Il tema è l'uso e le tecniche chirurgiche per l'inserimento di dispositivi di ancoraggio temporanei, definiti da TADS acronimo.
In questo contesto, con metodi diagnostici tradizionali e digitali e utilizzando materiali, strumenti e tecniche standardizzate è cresciuta notevolmente la prevedibilità della terapia stessa.
I vantaggi di questo nuovo dispositivo sono la minore richiesta di collaborazione da parte del paziente, con una notevole riduzione della necessità di ancoraggio dentale e riduzione dei tempi di lavorazione.
Grazie a tali dispositivi medico-chirurgici, il dentista è in grado di offrire al tempo stesso un trattamento soddisfacente e di alta qualità per il paziente.
L'uso e l'applicazione dei TADS è parte di un contesto multidisciplinare che coinvolge più professionisti appartenenti a diversi rami dentali. L'insieme dei dispositivi di ancoraggio temporanei include gli impianti osteointegrati, le piastre di mini-ancoraggio e mini-viti.
Questo documento illustra le tecniche chirurgiche di inserimento di mini-viti.<br>Research in the field of medicine makes day after day important steps toward new frontiers. In dentistry, much progress has been achieved in recent decades, in fact clinicians driven by the need to realize the therapies that were more and more advanced, valid and reliable over time have adopted techniques to take into account the numerous and high patient needs , such as important aesthetic expectations, comfort during therapy (not to underestimate the psychological aspect of patients that may affect social relationships in their daily).
The demand for orthodontic treatment by adults has increased in recent years. The adult population often presents reduction of periodontal supporting tissue and different treatment goals compared to the pediatric and adolescent population.
The biomechanical compromise to be able to respond more simply to this twofold component is the use of simple and effective anchoring devices: the TADS (from English Temporary Anchorage Devices).
The topic is the use and surgical techniques for inserting temporary anchorage devices, defined by TADS acronym.
In this context, using traditional and digital diagnostic methods and using materials, tools and standardized techniques has grown considerably the predictability of the therapy itself.
The advantages of this new device are the smaller demand for collaboration by the patient, with a remarkable reduction of the need for dental anchor and reduction of processing times.
Thanks to such medical-surgical devices, the dentist is able to offer at the same time a satisfactory treatment and high quality for the patient.
The use and application of the TADS is part of a multidisciplinary context involving more professionals belonging to different dental branches. The set of temporary anchorage devices includes the osseointegrated implants, the mini-anchor plates and mini-screws.
This paper will discuss the surgical techniques of insertion of mini-screws.
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Huang, Cheng-Tsung, and 黃丞聰. "Investigation of the contact between dental root and miniscrew during orthodontic tooth movement—an animal study." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/51831592482079303813.
Full textAbstract:
碩士<br>國立臺灣大學<br>臨床牙醫學研究所<br>96<br>Skeletal anchorage plays an important role in contemporary orthodontics. Miniscrew, which is one of the most frequently used temporal anchorage device (TADs), is famous for its small size, versatile usage, low price, and ease of insertion and removal. However, there are risks of root damage if we move a teeth to contact a miniscrew being inserted between two roots. Therefore, we used histological analysis on experimental animals to realize the possible response of root and surrounding tissues during this traumatic incidence.
In dog A , both upper and lower arch first and second premolar were extracted. Miniscrew were placed over distal side of canine and mesial side of third premolar (without contacting miniscrews). Three weeks later, space between canine and third premolar was attempted to close with 150g NiTi coil spring. After fifteen weeks, active force was stopped and fixation was performed to reserve the relation between dental root and miniscrew. In dog B, force application was continued until experiment completed. Newly formed calcifying tissues were labeled with bone markers, and the experimental animals were sacrificed after 24 weeks. In order to observe the bone labeling markers and cell morphology surrounding miniscrews and tissues, samples were embedded with resin and sectioned with microtomes.
Experimental findings:（1）There were fibroblasts, collagen fibers and capillaries surrounding the screws and roots. Inflammatory cells and cementoclasts were not found on the damaged root surface.（2） Long and shallow defect areas were seen on root surface if dental root was indeed in contact with the miniscrew. However, irregular resorptive concavity also could be detected as orthodontically induced root resorption.（3）Root repair was not initiated over resorptive area if dental root and miniscrew were still in contact with each other. On the contrary, reparative cementum can be found over resorbed concavity if dental root was displaced away from miniscrew surface.
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"Bone to implant contact of miniscrew implants: Experimental evaluation of the effects of force, timing and location." THE TEXAS A&M UNIVERSITY SYSTEM HEALTH SCIENCE CENTER, 2008. http://pqdtopen.proquest.com/#viewpdf?dispub=1447072.
Full text
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Poon, Yi-Ching, and 潘怡靜. "Evaluation of palatal bone thickness and bone density for miniscrew placement in adults: A cone-beam computed tomography study." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/82562244455204954746.
Full textAbstract:
碩士<br>高雄醫學大學<br>牙醫學研究所<br>99<br>Objective: The purpose of this study is to evaluate palatal bone thickness and bone quality by using cone beam computerized tomograms and to determine if tongue position, presence of posterior dental crossbite, palatal morphology and Frankfurt-mandibular plane angle (FMA) are associated with palatal bone thickness.
Material and Methods: Cone beam computed tomography (CBCT) images were obtained from 30 male subjects (mean, ages 25.79 years; range, ages 23.9-27.7 years) and 28 female subjects (mean, ages 27.66 years; range, ages 25.0-30.3 years). Palatal bone thickness and bone density were measured at 20 unilateral locations along and lateral to midpalatal suture and posterior to incisive foramen. Tongue position and presence of posterior dental crossbite were recorded. Palatal height and palatal width were measured and used to calculate palatal index. Lateral cephalometric radiograph was synthesized from CBCT data and used to determine FMA of each subjects.
Results: Bone density measurements ranged from 492.87 HU to 797.32 HU. Females demonstrated higher bone density values compared to males at 18 locations. For bone thickness measurements, males showed greater palatal bone thickness at almost all sites, but only showed significant difference at 6 locations. Tongue position, presence of posterior crossbite, and palatal morphology did not show clinically significantly relationship with bone thickness. For females, FMA showed significant correlation with bone thickness at 12 locations.
Conclusion: Palatal bone density was greater in female group, but further studies are needed to determine the influence of this finding to clinical success rate of miniscrews. Tongue position, presence of posterior dental crossbite and palatal morphology did not associate with palatal bone thickness. Hyperdivergent females were found to have less bone thickness at mid-posterior palatal area.
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Moreno, Fábio Manuel Lagarto. "Modificações esqueléticas e dento-alveolares na expansão palatina com dispositivos MARPE." Master's thesis, 2020. http://hdl.handle.net/10284/10648.
Full textAbstract:
A expansão rápida da maxila assistida por mini-implantes ortodônticos (Microimplant-Assisted Rapid Palatal Expansion, ou MARPE) é uma alternativa para a correção da deficiência transversal da maxila em jovens adultos, sem recorrer à expansão palatina rápida cirurgicamente assistida ou à utilização de dispositivos de expansão dento-suportados. Devido à interdigitação das suturas, com o avançar da idade, existe a
possibilidade de provocar efeitos colaterais e frequentemente insucesso na expansão. A técnica MARPE baseia-se na ancoragem esquelética através de mini-implantes ortodônticos para a transmissão das forças de expansão diretamente às estruturas ósseas.
Com este trabalho, pretende-se realizar uma revisão da literatura sobre a técnica MARPE, para compreender melhor os efeitos esqueléticos e dento-alveolares deste método de expansão, utilizado para regularizar a discrepância transversal entre a mandíbula e a maxila.
Neste contexto, foi realizada uma pesquisa bibliográfica nas bases de dados eletrónicas PubMed e B-on, não tendo sido imposto qualquer limite temporal ou linguístico.<br>The miniscrew-assisted rapid palatal expansion (Microimplant-Assisted Rapid Palatal Expansion, or MARPE) is an alternative for the correction of transverse maxillary deficiency in young adults, without resorting to surgically assisted rapid palatal expansion or the use of tooth-borne maxillary expander . Due to the interdigitation of sutures, with advancing age, there is a possibility of causing side effects and often failure to expand. MARPE is based on skeletal anchorage through orthodontic miniscrew for the transmission of expansion forces
directly to bone structures.
With this work, it is intended to carry out a literature review on the MARPE technique to better understand the skeletal and dento-alveolar effects of this expansion method used to regularize the transverse discrepancy between the mandible and the maxilla.
In this context, a bibliographic search was performed in the electronic databases PubMed and B-on, with no temporal or linguistic limits imposed.
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Inglez, Josias Andrade. "Dispositivos intrabucais indicados para distalização de molares superiores." Master's thesis, 2018. http://hdl.handle.net/10284/7174.
Full textAbstract:
O tratamento ortodôntico-ortopédico facial tem por objetivo, além da correção da má oclusão e promover a estética, manter os dentes e estruturas em função, devolvendo ao paciente um sorriso agradável e uma boca saudável. O presente estudo tem por objetivo analisar os diferentes tipos de aparelhos de distalização de molares superiores. O que se pretende, fundamentalmente, é demonstrar os meios de distalização intrabucais, que não dependem da colaboração do paciente, para se atingir os objetivos ortodônticos-ortopédicos faciais, as forças distalizadoras indicadas, bem como os métodos de ancoragem utilizados nos distalizadores de molares superiores.<br>Orthodontic-orthopedic facial treatment aims to, in addition to malocclusion correction and aesthetic promotion, keeps the teeth and structures in function, restoring a pleasant smile and a healthy mouth to the patient. The present study intends to analyze the different types of upper molar distalization appliances. Indeed, the purpose is to demonstrate intrabuccal distalization methods, which do not depend on patient collaboration to achieve orthodontic-orthopedic facial goals. the indicated distal forces, as well as the anchoring methods used in the maxillary molars distalizers.
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Huang, Li-ling, and 黃莉玲. "Anodization of orthodontic archwires and orthodontic miniscrews." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/87318029242857662537.
Full textAbstract:
碩士<br>國立清華大學<br>化學工程學系<br>96<br>Dental archwires and miniscrews are frequently used in the orthodontic treatments which are very popular nowadays owing to various healthy and cosmetic reasons. Commercial titanium and titanium-based archwires and miniscrews are anodized and examined in this study. The β-Ti archwires with different colors are produced by anodization with different anodized voltages. The surface of anodized wire is titanium oxide, and the oxidation states of Ti vary from TiO2 on the surface to inwardly a mixture of TiO2 and Ti2O3. For most of the anodization conditions, the oxide layers are amorphous. The thickness of oxide layer is determined by TEM and AES. The color of the anodized β-Ti archwires are primarily controlled by the thickness of the oxides which increases with the magnitudes of the applied voltage. With longer anodization time, the archwires change to milky white color. Composition and structure analysis results of the milky white archwires indicate that it is still TiO2 on the surface, but the titanium oxide layers became crystalline. Ti-6Al-4V miniscrews with mesoporous surfaces are produced by anodization using electrolyte with a small amount of fluorine. The mesoporous surfaces could significantly affect the products' osseointegration properties which need to be further explored. In the study of friction experiments, the anodized β-Ti and Ni-Ti archwires shows lower friction than the β-Ti archwires in the conventional stainless steel bracket with elastomeric ligature. When the friction experiments are carried out using the Damon3MX self-ligating bracket rather than the conventional bracket, the friction is singnificantly lower for all the archwires with and witout anodization and no differences can be observed between various archwires.
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Liu, Te-Chun, and 劉得均. "Biomechanical investigation of miniscrews for orthodontic anchorage." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/09661690857240445198.
Full textAbstract:
碩士<br>國立成功大學<br>口腔醫學研究所<br>94<br>Anchorage control plays an important and determinant role in successful orthodontic treatment. Recently, orthodontic miniscrews, used as temporary implants, have been widely used for anchorage control in clinical practice. Compared to the traditional dental implant anchorage systems, the advantages of miniscrew are simple to insert and to remove, less trauma surgery, less limitation in implant position, immediate loading and less cost. However, the failure of miniscrews in clinic is still bothering the orthodontists. It was hypothesized that bone quality, miniscrew dimensions, implanted depth, exposed length and force conditions would contribute to the failure of miniscrew. The aim of the present study was to investigate the biomechanical influences of these factors in miniscrews for orthodontic anchorage by finite element method and clinical data analysis. Eleven patients were included with total 20 miniscrews applied for orthodontic anchorage for clinical analysis. In finite element simulations, the three-dimensional model of bone block integrated with miniscrew was built. The evaluated parameters included cortex thickness, cancellous bone property, miniscrew diameter, miniscrew length, implanted depth, exposed length, force magnitude and force direction. The maximum von Mises stress of cortex and displacement of miniscrew were investigated and compared. The results showed that the maximum von Mises stress of cortex concentrated in the compressed surface adjacent to the miniscrew and the maximum displacement of miniscrew located at the top of screw head in all models. The tendency of changes of the stress and displacement related to these parameters were similar. In general, both stress and displacement increased with the decreasing of cortex thickness, decreasing of miniscrew diameter, increasing of exposed length, and were linearly proportioned to the force magnitude and had the largest values in 90° force direction. For various lengths of miniscrew, these two indices were almost unchanged when the exposed lengths were equal with the implanted depths larger than 2 mm. For the same miniscrew, both stress and displacement varied insignificantly under various cancellous bone properties with cortex thickness greater than 0.5 mm. This study concluded that to increase the clinical success rate of miniscrew anchorage, the cortex should be thicker than 0.5 mm; the miniscrew diameter should be greater than 1.2 mm; the implanted depth should be longer than 2 mm; the exposed length should be as short as possible; the force magnitude should not exceed the clinical indications; and the force direction should prevent perpendicular to the miniscrew axis.
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Chen, Yuan-Hou, and 陳源厚. "Evaluation of Stability and Risks Using Miniscrews in Orthodontics." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/80459759748838382565.
Full textAbstract:
碩士<br>國立臺灣大學<br>臨床牙醫學研究所<br>93<br>Abstract
With more psychosocial and facial concerns, there is an increasing demand for orthodontic treatment to improve facial esthetics, speech, and chewing function. The success of orthodontic treatments relies on the precision of tooth movement with proper anchorage control. Recently, implant anchors such as miniscrews and miniplates have been used for absolute anchorage during orthodontic treatment. However, the potential problem of damaging the adjacent roots while mini-implants placement is a major concern. Therefore, we use animal experiments simulating orthodontic tooth movement to evaluate the risks of placing the miniscrews.
Eighty-four miniscrews were surgically placed in maxillary and mandibular alveolar bone at each side of 6 adult beagle dogs with metabolic bone labeling at three-week intervals. In experiment 1, the miniscrews were placed, retained for different time points and then removed in mandibular area with or without hitting the adjacent teeth. In experiment 2, a NiTi coil for orthodontic force (150g) was used to pull the maxillary fourth premolar (PM4) and the canine towards each other for 6 months after a miniscrew was placed in the furcation of PM3 with or without intentional root damaging. The insertion torque, clinical measurements every three weeks, the removal torque, and the histological findings were analyzed.
In the animal study, we demonstrated that (1) the values of insertion torque were significantly higher in the mandible than those in the maxilla. The miniscrews contacting with the roots showed a significantly higher insertion torque than those without contact. (2) For removal torque: there was a significant difference of the removal torque measurements for the following variables: the mobility of miniscrew, the state of root contact, and the duration of miniscrew in place (3 weeks vs. 24 weeks). (3) The miniscrews contacting with the root was at greater risks for failures. (4) From histological findings: the failed miniscrews were surrounded with more soft tissue with inflammation. When more inflammation was present, it seems that the adjacent roots experienced more surface resorption. However, some of the inflammation induced root resorption could be repaired with surface deposition of mineralized tissue, likely the cellular cementum, or being partially filled with alveolar bone, both labeled with fluorophore markers.
The other purpose of this study was to measure the removal torque of the immediately loaded miniscrews in orthodontic patients after clinical usage and to find the possible factors associated with this value. From twenty patients with malocclusions, 35 miniscrews were removed and the removal torque was measured with a torque gauge. Removal torque values were subjected to statistical analysis for possible association of different clinical characteristics. The removal-torque value of 75% miniscrews was above 0.5kgcm. These values were significantly higher in the mandible than those in the maxilla. However, we could not detect a significant association between the removal-torque value and the following variables: age, gender, screw length, healing time and time in function. For uprighting tipped molars using anchorage from miniscrew, excessive torque in the counterclockwise direction may loosen it. From our measurement, the miniscrews should be able to sustain an uprighting moment in order for a more precise tooth movement.
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Chang, Chin-Shan, and 張金山. "The effect of microrough surface treatment on miniscrews used as orthodontic anchors." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/42570961490423005475.
Full textAbstract:
碩士<br>國立成功大學<br>口腔醫學研究所<br>95<br>Anchorage control continues to be a very important issue in orthodontic treatment and plays a key role for successful treatment. Compared to traditional anchorage devices, intraosseous anchors are more effective, efficient, and can be used for non-compliance anchorage source. In recent years, as an intraosseous anchorage source, miniscrews are used in clinical orthodontic treatment. In comparison with prosthetic dental implant, miniscrews have advantages of easier surgical installation, immediate loading, less cost and easier removal after orthodontic treatment. Miniscrew is made of pure titanium or Ti alloy, and its diameter is much smaller than that of implant. However, previous studies on the relationship between microroughness surface treatment and osseointrgration focused only on prosthetic dental implant. There were limited studies regarding the effect of surface treatment on miniscrews. The aim of this study is to investigate the effects of 4 different microrough surface treatments on miniscrews as orthodontic anchors. The study is divided in two parts. Part I is an in vitro study. Ti alloy discs with 12.8mm diameter received surface treatment of acid etching, sandblasting, sandblasting & acid etching, and sandblasting & alkaline etching. Ti alloy discs by different treatment are checked with profilometer and SEM to identify the surface roughness and morphological character. Cell culture is done for observing their biocompatibility by cell proliferation in 1, 4, and 7 days. It shows that sandblasting significantly effect surface roughness, and different surface treatment fabricates different surface morphology. Part II is an animal study. Twenty-four New Zealand white rabbits are selected. Three miniscrews are implanted in each tibia of the rabbits. Orthodontic forces with Ni-Ti coils are applied immediately to miniscrews in each tibia. After 2, 4, 8 and 12 weeks, the rabbits are sacrificed. The removal torque is tested first, and histomorphometry and miniscew-bone contact are examined. The differences in removal torque are analyzed by Mann Whitney U test. The result shows that sand blasting is the major factor influence surface roughness, and different surface treatment makes different surface topography. The optical density of Po surface was significantly increased form day 1 to day 4. In loaded condition, RTV of SLA surface increased significantly after 4 weeks of healing. The RTV of SL/NaOH surface increased after 8 weeks of healing, and reached a significant difference with SLA surface after 12 weeks of healing. After 12 weeks of healing, the BIC of SLA and SL/NaOH surface was higher than smooth surface. After test with regression model, the correlation of BIC and RTV was moderate. A systemic and interdisciplinary work must be required to be able to make a sound prediction of bone-healing process from a removal torque testing.
By integrating biocompatibility, histological finding and removal torque analysis, we hope to provide the best method of surface treatment on miniscrews to increase the anchor force of miniscrews and the success rate of treatment.
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Ko, Hsiu-Ching, and 柯秀靜. "Surface Treatment of 316L stainless steel in the application of orthodontic miniscrews." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/03570311190151453447.
Full textAbstract:
碩士<br>國立臺灣大學<br>臨床牙醫學研究所<br>103<br>With the advances of dental implants, temporary skeletal anchorage devices have now become established orthodontic anchorage aids and launched a new era for clinical orthodontic therapy. In recent years, numerous publications have investigated multiple factors affecting success rates of orthodontic mini-screws, such as shape design, material science, or surface topography. The success rate of 316L stainless steel orthodontic miniscrews was found to be lower than titanium alloy, and our research goal was to make surface modification by coating a TiO2 thin film on 316L stainless steel, which aimed to improve the biocompatibility and induce osseointegration.
The 316L stainless steel plates were used in this study to test mechanical conditions. The experimental variables were included as follow: 1. Coating methods : ion-beam assisted electron beam evaporation and sol-gel method for titanium;2 Coating thickness, ranging from 30 to 500 nm; 3. Surface roughness. The composition and crystalline phase were analyzed by Energy Dispersive Spectrometer (EDS) and X-ray diffraction analyzer (XRD). The surface and cross-section of films were examined by scanning electron microscope. And the color three-dimensional laser scanning analyzer was used to analyze the surface roughness of films. Finally, the film adhesion under various coating parameters was evaluated by a scratch test machine. Besides, all the data would compare with the previous results of magnetron sputtering and produce a comprehensive view of those results.
The study results showed that TiO2 thin film with good quality and dense
structure can be coated on 316L stainless steel by magnetron sputtering, electron beam
evaporation, and sol-gel method. The magnetron sputtering can produce best results regarding to film adhesion and crystallization structure. The sol-gel method also could produce thin film with good adhesion property and crystallization structure after rapid thermal annealing. However, the ion-beam assisted electron beam evaporation can produce thin film with dense structure, but the adhesion property was poorer than magnetron sputtering and sol-gel method. Besides, the film thickness played an important role in the adhesion property, and the surface roughness was not altered by the coating.
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Chu, Ting-Wei, and 朱庭緯. "Surface treatment of 316L stainless steel in the application of orthodontic miniscrews-Mechanical analysis." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/ed8sz5.
Full textAbstract:
碩士<br>國立臺灣大學<br>臨床牙醫學研究所<br>101<br>In recent years, with the increased application of the orthodontic bony anchorage, it had been proposed to improve the clinical success rate of orthodontic mini-screws by a variety of modification of screw geometry, material or surface morphology. Our intention in this study was to modify the surface of stainless steel by surface coating of biocompatible films and improve the biocompatibility and the capability of bone integration.
The 316L stainless steel plates with the same composition of orthodontic stainless steel screws were used in this study to eliminate variables and simplify the mechanical testing conditions. The experimental variables were included as follow: 1. Coating materials. Titanium and titanium dioxide. 2. Coating methods. Magnetron sputtering or sol-gel method for titanium dioxide film. And magnetron sputtering or electron beam evaporation method for titanium film. 3 Coating thickness. With the range of 30 to 500 nm. 4. Surface roughness.
The composition and crystalline phase were analyzed by electron probe microanalyzer (EPMA) and X-ray diffraction analyzer (XRD). The surface and cross-section of films were examined by field emission scanning electron microscope. And the color three-dimensional laser scanning analyzer was used to calculate the surface roughness of films. Finally, the film adhesion under various coating parameters was evaluated by a scratch test machine.
The study results show that the titanium film could be made by the magnetron sputtering or the electron beam evaporation method. However, poor adhesion between the titanium coating and the substrate was noted by the scratch test. On the other hands, regardless of the coating methods by magnetron sputtering or sol-gel method, the
v
titanium dioxide film performed good adhesion properties. In addition, the film thickness and surface roughness does affect the property of film adhesion. The ability of spalling resistance was improved by increased coating thickness and by increased surface roughness. But the crack resistance property was weaken with increase of the surface roughness of films.
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Wu, Kuan-Yi, and 巫冠誼. "Investigation of the removal torque of miniscrews after giving different direction of moment—an animal study." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/65394801329323217156.
Full textAbstract:
碩士<br>國立臺灣大學<br>臨床牙醫學研究所<br>97<br>Miniscrews, which are different from traditional dental implants, can be loaded immediately or quite early after primary stability established. New design of its head structure , with a bracket slot , tube, or hole, can be connected to a sectional wire in order to achieve three dimenisional control of tooth movement during orthodontic treatment. However, this mechanical design would give a moment, which may endanger the stability of the miniscrews. Therefore, we used animal experiments to simulate this type of loading on miniscrews to test its effect on the miniscrew stability.
Eighty miniscrews (2.0mm diamter, 11mm length) were surgically placed in maxillary and mandibular alveolar bone between canine and first molar in 3 adult mongrel dogs. At each quardrant, we bonded the brackets on the posterior miniscrews. At left side, we gave a clockwise moment to the posterior miniscrew by cantilever arm devices. At right side, we gave a counter-clockwise moment to the posterior miniscrew. The total experimental time was six months in dogs A and B, and seven months in dog C. Each dog was given metabolic bone labeling at three-week intervals. Clinically, we recorded the insertion torque, the removal torque and loading time of each miniscrews before animals sacrificed. In order to observe the tissue changes at interface of bone and miniscrews, samples were embedded with resin and sectioned with microtomes, and the results were evaluated under a microscope By multivariate logistic regression method, parameters from clinical data and histological results were analysed for their influences on removal torque.
Clinical data showed: 1) In some areas, the brackets on miniscrews were rotated gradually by the given moment. 2) There was a significant positive correlation between the loading time of miniscrews and the removal torque, but not the other variables. 3) There was no significant difference in the removal torque between the clockwise- and counter-clockwise groups. 4) The values of insertion torque were significantly higher in the mandible than those in the maxilla.
Histological finding showed:1) Higher bone to implant contact (BIC) ratio was found towards the tip of the miniscrews. 2) In experimental loading group, there seems to be more flurorence labeled bone tissue surrounding the miniscrews.
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Yadav, Sumit. "Histomorphometric and Biomechanical Analyses of Osseointegration of Four Different Orthodontic Mini Implant Surfaces." Thesis, 2011. http://hdl.handle.net/1805/2704.
Full textAbstract:
Indiana University-Purdue University Indianapolis (IUPUI)<br>Objective: To evaluate the osseointegration potential of four different surfaces of mini-implants .We hypothesized that mini-implants surface roughness alters the intrinsic biomechanical properties of the bone integrated to titanium. Materials and Methods: Mini implants and circular discs were made from alloy Ti6Al4V grade 5. On the basis of surface treatment study was divided into 4 groups: Group 1: Machined: no surface treatment, Group 2: Acid etched: with hydrochloric acid, Group 3: Grit Blasted with alumina and Group 4: Grit blasted +Acid etched. Surface roughness parameters (mean surface roughness: Ra and Quadratic Average roughness: Rq) of the four discs from each group were measured by the optical profilometer. Contact angle measurement of 3 discs from each group was done with a Goniometer. Contact angle of liquids with different hydrophobicity and hydrophilicity were measured. 128 mini implants, differing in surface treatment, were placed into the tibias and femurs of 8 adult male New Zealand white rabbits. Biomechanical properties (Removal torque and hardness) measurements and histomorphometric observations were measured. Results: Ra and Rq of groups were: Machined (1.17±0.11, 2.59±0.09) Acid etched (1.82±0.04, 3.17±0.13), Grit blasted (4.83±0.23, 7.04±0.08), Grit blasted + Acid etched (3.64±0.03, 4.95±0.04) respectively. Group 4 had significantly (p=0.000) lower Ra and Rq than Group 3. The interaction between the groups and liquid was significant. Group 4 had significantly lower contact angle measurements (40.4°, 26.9°), both for blood and NaCl when compared to other three groups (p≤0.01). Group 4 had significantly higher torque than Group 3 (Tibia: 13.67>9.07N-cm; Femur: 18.21>14.12N-cm), Group 4 (Tibia: 13.67>9.78N-cm; Femur: 18.21>12.87N-cm), and machined (Tibia: 13.67>4.08N-cm; Femur: 18.21>6.49N-cm). SEM analysis reveals significantly more bone implant gap in machined implant surfaces than treated implant surfaces. Bone to implant contact had significantly higher values for treated mini implant surface than machined surface. Hardness of the bone near the implant bone interface is 20 to 25% less hard than bone 1mm away from it in both Femur and Tibia. Conclusion: Surface roughness and wettability of mini implants influences their biological response. Grit blasted and acid etched mini implants had lowest contact angle for different liquids tested and highest removal torques.
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Luna, Arethuza Carolina Brochado. "Aplicação clínica dos mini-implantes ortodônticos como método de ancoragem." Master's thesis, 2018. http://hdl.handle.net/10284/7131.
Full textAbstract:
Na Ortodontia um dos factores mais importantes do tratamento é ancoragem. Fornecer e controlar
um sistema de ancoragem absoluta é um problema comum na prática. Para solucionar este
problema, lançava-se mão de dispositivos extra e intra-orais. Entretanto, alguns destes, não eram
facilmente aceitos pelos utentes. Enfatizando diminuir a cooperação dos mesmos e estender as
possibilidades de tratamento, vários tipos de mini-implantes têm sido aplicados como âncoras,
conferindo uma ancoragem absoluta para auxiliar o tratamento. A proposição para uso de miniimplantes,
servindo de apoio a uma variedade grande de movimentos e por tempo indeterminado
é uma alternativa útil para resolver os problemas de ancoragem. Sobretudo, devido a sua alta
versatilidade clínica, tamanho reduzido, simples cirurgia de instalação, possibilidade de carga
imediata, facilidade de colocação e remoção. No presente estudo foram apresentadas situações
clínicas utilizando mini-implantes, foram citadas suas vantagens e desvantagens. Actualmente as
suas aplicações clínicas têm sido aceitas e ampliadas.<br>Anchorage is one of the most important factor that affects the orthodontic treatment. Control and
provide a system of absolute anchorage is an usual problem in practice. Until now, to solve this
problem various techniques to reinforce anchorage have been devised and used an extraoral and
intraoral appliances. However, some of them were not easily accept. Emphasizing to reduce
demands minimum patient cooperation and enlarge treatment possibilitys, several kinds of miniimplants
have been used as anchors providing anchorage to assist treatment. The purpose of
mini-implants an useful alternative has provided clinicians with a reliable means of solving
anchorage problems for undetermined time. Therefore, has shown to be highly acceptable
because of their reduced size, easy placement and removal, low cost, simpler placement surgery,
in addition orthodontic force can be applied to them almost immediately after implantation. In the
present study were presented mini-implants in clinical applications, related following advantages
and disadvantages. Current their clinical applications have been expanded and adopted.