Dissertations / Theses on the topic 'Orthodontic aligner'

The purpose of this study was to investigate differences in case confidence, treatment management, and Invisalign® expertise between orthodontists and general dentists. A survey was mailed to 1,000 randomly selected orthodontists and general dentists, respectively, who are Invisalign® providers, and results were analyzed. The results indicated that orthodontists treated significantly more Invisalign® cases and received more Invisalign® training than general dentists (P

Purpose: To evaluate the factors that influence potential orthodontic patients choosing between an orthodontist, general dentist, and direct-to-consumer (DTC) aligners for their treatment, and to determine the demand for each provider type. Methods: An electronic survey was administered to 250 individuals among the general population of adults in the United States. Questions were designed to determine the respondent’s level of interest in pursuing orthodontic treatment with each provider type, evaluate their current level of knowledge concerning provider options, and identify factors influencing their selection. Pearson’s chi-squared test and ANOVA were used to evaluate the factors influencing patients in their selection. Results: When asked their preference in provider type, 43.8% of respondents selected orthodontist, 34.1% selected DTC aligners, and 22.1% selected general dentist. Among respondents with the highest level of interest in pursuing orthodontic treatment, 50% selected an orthodontist and 27% selected DTC aligners. For respondents with moderate levels of interest in pursuing treatment, only 21% selected an orthodontist and 48% selected DTC aligners. The biggest perceived advantage of treatment with an orthodontist was quality of treatment, and the biggest disadvantage was cost. For DTC aligners, the biggest perceived advantage was convenience, followed by cost, and the biggest disadvantage was quality of treatment. Among adults with children, 34% selected DTC aligners for themselves and only 16% selected DTC aligners when selecting for their children. Conclusion: Adults in the United States have similar levels of interest in pursuing orthodontic treatment with orthodontists and DTC aligners and, to a lesser degree, general dentists. A significant portion of those who select DTC aligners for their treatment are patients who would not have otherwise undergone treatment with an orthodontist. Patients tend to select orthodontists due to quality of treatment, whereas DTC aligners are selected due to convenience, followed by cost. Even among parents who prefer DTC aligners for their own treatment, parents tend to select an orthodontist for their child’s treatment.

Oral Biology
M.S.
The relationship between applied force and aligner thickness is poorly understood. Therefore, the aims of the present study were to: 1) Evaluate the effect of initial material thickness on force output of clear aligners; and 2) Recommend a consistent, repeatable method for measuring aligner cross-section and distribution. A total of 40 clear aligners were fabricated over stereolithographic (SLA) models with ideal dentition, using proprietary gRxh material in four different thicknesses: (10) Rx15 [0.015h], (10) Rx20 [0.020h], (10) Rx30 [0.030h], (10) Rx40 [0.040h]. For measuring initial force output when tipping a tooth, a custom-made force measurement apparatus (FMA) was used with the upper right central incisor translated facially 0.25 mm. All six components of force and torque were measured (Fx, Fy, Fz, Tx, Ty, Tz) over a 16 second period of time upon seating each aligner. After gathering FMA data, cross-section and distribution of aligner material thickness was then measured using three methods for comparison: hall effect transduction, computed tomography (CT) scanning, and cross-sectional analysis under a stereomicroscope. All measurements were taken along the mid-sagittal plane of the facial surface of the upper right central incisor. Force output and variability both generally increased with an increase in material thickness. The range of measured forces were 3.5 to 28 times higher than ideal tipping forces reported by Proffit. The results for lingual force correlated well with those of total force (ã(Fx)2 + (Fy)2 + (Fz)2). As for the thickness measurement results, the hall effect transducer (HET) data correlated well with that of the CT scan. The stereomicroscope produced values that were relatively elevated. Mean measurements taken with both HET and CT consistently got smaller when moving from occlusal to middle to gingival points. The same trend was noted with the stereomicroscope, but with less consistency. The thinner Rx15 material appeared best suited for lingual tipping of a maxillary central incisor in vitro. The hall effect transducer produced simple measurements that were extremely similar to those from the CT scan, and appears to be a suitable stand-in for the more expensive and labor intensive CT scanning process.
Temple University--Theses

Introduction: Surgically Facilitated Orthodontic Therapy (SFOT) has been utilized for years to overcome the limitations encountered with traditional orthodontic treatment of dentoalveolar and alveoloskeletal malocclusions. The procedure, which consists of full flap corticotomies and bone grafting, has many proposed benefits including increased speed and range of tooth movement. The purpose of this study is to evaluate arch expansion in patients treated with SFOT and clear aligners. Materials and Methods: A retrospective cohort study design was used to evaluate 51 consecutive adult patients that were treatment planned for significant arch expansion with corticotomies, bone grafting, and clear aligners. 17 of the 51 patients refused the surgical procedure and served as controls. Eight transverse arch width measurements were obtained at three different time points (Initial, ClinCheck, Refinement). Five calculations were performed to determine the magnitude, predictability, and efficiency of arch expansion. Results: The difference in treatment time between the two groups was statistically significant at 5.2 months (P < .0001). On average, corticotomies reduced the length of treatment by 46% and increased the rate of expansion 2.4x. Patients that received SFOT achieved a greater magnitude (+28%) of expansion at a significantly higher rate (P< 0.002) than controls for all eight interarch measurements. The SFOT group displayed higher predictability (% goal achieved) and a smaller difference between predicted and achieved tooth movements for all measures obtained. The mean age for the entire sample was 42.81 (+12.51 years). Conclusion: Arch expansion with corticotomy-assisted clear aligner therapy is significantly more effective, efficient, and predictable than with clear aligners alone. The predictability of expansion with aligners appears to have a higher range than initially thought, even in patients that do not receive corticotomies.

ABSTRACT EVALUATION OF FIT FOR 3D PRINTED RETAINERS AS COMPARED TO THERMOFORM RETAINERS By David Cole, D.M.D. A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Dentistry at Virginia Commonwealth University Thesis Directors: Eser Tüfekçi, D.D.S., M.S., Ph.D., M.S.H.A. Professor, Department of Orthodontics Sompop Bencharit, D.D.S., M.S., Ph.D. Associate Professor and Director of Digital Dentistry, Department of General Practice Introduction: Despite recent advances in three-dimensional (3D) printing, little information is available on 3D printed retainers Methods: Three reference models were used to fabricate traditional vacuum formed, commercially-available vacuum formed, and 3D printed retainers. For each model, three retainers were made using the three methods (a total of 27 retainers). To determine the trueness, the distances between the intaglio surface of the retainers and the occlusal surface of the reference models were measured using an engineering software. A small difference was indicative of a good fit. Results: Average differences of the traditional vacuum formed retainers ranged from 0.10 to 0.20mm. The commercially-available and 3D printed retainers had a range of 0.10 to 0.30mm and 0.10 to 0.40mm, respectively. Conclusions: The traditional vacuum formed retainers showed the least amount of deviation from the original reference models while the 3D printed retainers showed the greatest deviation.

Introduction: Orthodontic and orthopedic expansion is necessary to create space to resolve crowding due to arch deficiency or tooth size discrepancy. The Invisalign First clear aligner appliance as a modality for early interceptive orthodontic treatment has become incorporated into orthodontic practices in very recent years. The present study aims to investigate the magnitude of expansion of the Invisalign First clear aligner appliance compared to a Schwartz removable expander in patients with mixed dentition. Additionally, the study aims to compare the efficacy and predictability of Invisalign First clear aligners in this population. Materials & Methods: In this retrospective study, a sample was collected from a single orthodontist practitioner. The sample consisted of 34 patients, 16 patients treated with Invisalign First clear aligners only (Group1) and 19 patients treated with a Schwartz removable appliance and Invisalign First clear aligners (Group 2). Intraoral scans of four timepoints, initial (T1), post-expansion for Group 2 only (T1Exp), first refinement (T2), and final (T3), and planned Clincheck goal (P) model from Clincheck software were imported to Align Technology’s digital measure program (Quantify©). Arch widths and molar inclinations were measured at each timepoint and the changes between timepoints were calculated. Predictability of arch expansion was calculated as T13 (change between initial and final) divided by the Planned dimension multiplied by one hundred. A two sample t-test was used to assess differences in the changes in arch widths and predictability of expansion between two groups. Results: There were statistically significant differences found in the magnitude of expansion and predictability of arch expansion between two groups. Group 2 showed a greater amount of expansion and predictability. Group 1 showed about 50-60% of the planned expansion at the end of treatment. In regards to magnitude of expansion when comparing the two groups, the efficacy predictability of transverse dimensional changes were significantly greater in the Group 2 compared to Group 1, 83% vs 56% (p = 0.001), respectively. The changes in inclination were similar in both groups, with no statistically significant differences.Conclusions: There is a significantly greater amount of expansion and greater predictability with the Schwartz removable appliance compared to the Invisalign First clear aligner appliance in the mixed dentition. The predictability of Invisalign First was 56% and indicates a significant overcorrection of arch expansion is required at the virtual treatment planning stage in Clincheck in order to obtain the arch expansion that was planned

Dissertação para obtenção do grau de Mestre no Instituto Universitário Egas Moniz
Introdução: O avanço na Ortodontia que ocorreu nas últimas décadas foi impulsionado pela demanda estética. O aumento do interesse dos adultos na correção dentária impõe o fator estético como ponto determinante na decisão do tipo de aparelho ortodôntico a utilizar. Assim sendo, os alinhadores surgem como uma alternativa aos dispositivos multibrackets com arcos, uma alternativa não só confortável, mas também impercetível. Por sua vez, a responsabilidade de se realizar atualizações frequentes e conhecer as aplicações e principalmente limitações da nova técnica, é unicamente do Ortodontista. Objetivos: Esta revisão de literatura tem como objetivo avaliar as vantagens, desvantagens e eficácia clínica da Ortodontia Plástica em comparação com os sistemas multibrackets. Metodologia: Para a busca eletrônica de artigos usamos as seguintes bases de dados: “Cochrane”, “ScienceDirect”, “B-on”, “Google Acadêmico” e finalmente o “PubMed”. Restringimos a pesquisa a artigos na língua portuguesa, inglesa e espanhola publicados desde 2013 incluindo todos os tipos de estudo com preferência pelas revisões sistemáticas e meta-análises, bem como artigos chave listados nas referências dos artigos selecionados. Recorremos ainda ao arquivo bibliográfico do IUEM. Conclusão: Concluímos neste trabalho que as vantagens do uso dos alinhadores plásticos como aparelho ortodôntico apresentam a estética como principal ponto de decisão, seguido do conforto do paciente e por último da higiene oral. Por outro lado, a desvantagem dos sistemas plásticos está atualmente relacionada com a limitação de tipos de movimentos ortodônticos, sendo estes os movimentos de extrusão, rotação e torque os mais difíceis de serem alcançados. Acreditamos que avanços na tecnologia ocorrem continuamente e podem vir a mudar definitivamente as limitações ortodônticas dos alinhadores plásticos.

Objective: To assess in orthodontic treatment the distalization of uppers molars with invisalign Materials and methods: A literature review was carried out through articles and journals retrieved from the “PubMed" data base using the following keywords "orthodontic treatment", "tooth movement technique", "aligner appliances", "invisalign", "removable orthodontic appliance” “clear aligners”. Several articles were pre-selected, of which 24 were used to compose write this document. Discussion: Clear aligner as an orthodontics treatment during the distalization purposes has been a controversial topic due to its complexity and lees studies. In This paper provides a deeper knowledge of the distalization in upper molars under invisalign treatment enable and helping professionals to make the right decision when planning orthodontic treatment. Conclusion: The Upper Molars Distalization with clear aligner could be effective, being able to reach up to 3mm of movement; however, is very important for the clinician to develop a thorough knowledge of the current Align Protocol and to acquire sufficient Invisalign experience before attempting the complex movements required for successful completion of these types of cases.

O sistema de alinhadores do sistema Invisalign® foi introduzido como uma alternativa estética ao uso de brackets no tratamento ortodôntico. Os alinhadores são aparelhos removíveis transparentes feitos à medida e capazes de induzir movimento dentario. Face a uma maior procura por parte dos pacientes, este sistema tem evoluído significativamente com o objetivo de atingir resultados semelhantes aos obtidos com os tratamentos convencionais com brackets. Levando em conta os fatores que podem influenciar o movimento dentário ortodôntico, através de uma revisão bibliográfica, a autora deste trabalho teve como objetivo a avaliação da eficácia e eficiência do sistema Invisalign®.
Clear aligners of the Invisalign® system were introduced as an aesthetic alternative to the use of brackets in orthodontic treatment. The aligners are custom-made removable transparent appliances capable of inducing tooth movement. Faced with increasing patient demand, this system has evolved significantly in order to achieve results similar to those obtained with conventional brackets treatments. Taking into account factors that may influence orthodontic tooth movement, through a bibliographic review, the author of this work had the objective of evaluating the effectiveness and efficiency of the Invisalign® system.

Os sistemas de alinhadores surgiram devido ao aumento da exigência estética do tratamento ortodôntico pelos pacientes. Graças ao desenvolvimento destes sistemas e ao aumento da procura verifica-se uma evolução significativa, cujo objetivo é atingir resultados semelhantes aos obtidos com os aparelhos ortodônticos fixos convencionais, no entanto, existem outros fatores que diferem entre estes dois sistemas. Esta revisão bibliográfica tem como principal objetivo realizar uma comparação entre o aparelho ortodôntico fixo convencional e o sistema Invisalign® em relação a alguns fatores, nomeadamente, à saúde periodontal, à dor, às reabsorções radiculares e à eficácia dos tratamentos. Para além do sistema Invisalign® ter como vantagem a estética, é possível concluir que com este sistema os pacientes apresentam maior conforto, menos dor e melhor saúde periodontal, proporcionando maior qualidade de vida, contudo, não estão indicados em todos os pacientes, uma vez que, são mais eficazes no tratamento de maloclusões leves a moderadas.
The aligners system emerged due to the increase in the aesthetic demand of orthodontic treatment by patients. With the development of these systems and the increase in demand, a summarized evolution has been achieved, the objective being to achieve results like those obtained with conventional fixed orthodontic appliances, however there are other factors that differ between these two systems. The main objective of this literature review is to make a comparison between the conventional fixed orthodontic appliance and the Invisalign® system in relation to some factors, namely periodontal health, pain, root resorption and the effectiveness of treatments. In addition to the aesthetic advantage of the Invisalign® system, it is possible to conclude that with this system patients have greater comfort, less pain and better periodontal health, providing a better quality of life, however, they are not indicated for all patients, since they are more effective in the treatment of mild to moderate malocclusions.

I sistemi biologici e biomedici presentano delle caratteristiche tali da renderli a tutti gli effetti assimilabili a dei sistemi meccanici complessi. In questo lavoro di tesi si presentano le ricerche condotte in due diversi ambiti di studio della biomeccanica. Nella prima parte, sono stati studiati gli effetti degli ultrasuoni a bassa intensità sulle cellule tumorali. Diversi studi dimostrano che il calore, la cavitazione e l'ipertermia indotti dagli ultrasuoni possono produrre effetti antitumorali. Inoltre, la terapia ad ultrasuoni a bassa intensità può svolgere un ruolo positivo nella cura del cancro causando danni alla membrana delle cellule tumorali, inducendo l'apoptosi e migliorando l'effetto dei farmaci anticancro. In questo lavoro vengono presentati gli effetti degli ultrasuoni a bassa intensità su due particolari linee cellulari tumorali: l'osteosarcoma MG63 ed il linfoma U937. Le cellule di osteosarcoma MG63 sono state sonicate per 180 secondi a frequenze fisse comprese tra 400 e 1.000 kHz. I risultati hanno mostrato che la mortalità delle cellule MG-63 raggiungeva valori pari a oltre il 60% per valori di frequenza pari a 1.000 kHz. Inoltre, il monitoraggio del comportamento cellulare dopo il trattamento con ultrasuoni ha mostrato che il trattamento produce effetti sulla proliferazione cellulare anche dopo la sonicazione. Risultati interessanti sono stati ottenuti anche sulla linea cellulare U937, per la quale il trattamento con ultrasuoni a frequenza fissa a 1 MHz ha determinato una mortalità cellulare pari a oltre l'80%. Nella seconda parte di questo lavoro è stato studiato il comportamento meccanico degli allineatori ortodontici. Gli allineatori sono dispositivi medici in grado di produrre il movimento di uno o più denti attraverso una serie di passaggi decisi dall'ortodontista. In particolare, sono stati considerati due diversi aspetti del comportamento meccanico di questi dispositivi. In primo luogo, sono state considerate le pressioni specifiche esercitate dagli allineatori sui denti e le aree dove vengono applicate tali pressioni. I risultati hanno mostrato che le pressioni esercitate dall'allineatore non sono distribuite uniformemente su tutta la superficie del dente e che, per diversi allineatori realizzati su uno stesso modello, le aree di applicazione delle forze non erano identiche, poiché influenzate da fattori risultanti dai processi di fabbricazione. Un secondo studio ha investigato la stabilità dimensionale degli allineatori dopo l'applicazione di stress dinamico in vivo e stress statico in vitro. Sono stati testati tre diversi materiali tipicamente utilizzati per la realizzazione degli allineatori (PET-G, PET e SmartTrack®). Gli effetti dello stress dinamico prodotto in vivo sono stati valutati facendo indossare ad un paziente i tre diversi allineatori per un periodo di due settimane. Gli effetti dello stress statico, invece, sono stati valutati sottoponendo gli allineatori ad un carico statico mediante macchina di prova. Gli allineatori testati sono stati scansionati e misurati al fine di valutare la loro stabilità dimensionale dopo i diversi tipi di sollecitazioni. I risultati hanno mostrato che gli allineatori PET sembrano avere la più bassa percentuale di deformazione, mentre gli allineatori PET-G e SmartTrack® mostrano una deformazione ridotta che va dalla zona posteriore a quella anteriore. Infine, è stato dimostrato che il contatto con la saliva umana induce una maggiore deformazione.
Biological and biomedical systems present characteristics that make them equivalent to complex mechanical systems. In this thesis, the research conducted on two different fields of biomechanics is presented. In the first part, the effects of low intensity ultrasound on cancer cells were studied. Several studies show that heat, cavitation and hyperthermia induced by ultrasound can produce anticancer effects. In addition, low intensity ultrasound therapy can play a positive role in the treatment of cancer by causing damage to the cancer cells membrane, inducing apoptosis and improving the effect of anticancer drugs. In this paper, the effects of low intensity ultrasound on two particular tumour cell lines are presented: the osteosarcoma MG63 and the U937 lymphoma. MG63 osteosarcoma cells were sonicated for 180 seconds at fixed frequencies between 400 and 1,000 kHz. Results showed that mortality of MG-63 cells reached values of over 60% for 1,000 kHz frequency. Furthermore, monitoring cellular behaviour after ultrasound treatment showed that the treatment has effects on cell proliferation even after sonication. Interesting results were also obtained on U937 cell line, for which the treatment with fixed frequency ultrasound at 1 MHz resulted in a cell mortality of over 80%. In the second part of this work the mechanical behaviour of orthodontic aligners was studied. The aligners are medical devices able to produce the movement of one or more teeth through a number of steps decided by the orthodontist. In particular, two different aspects of the mechanical behaviour of these devices have been considered. First, the specific pressures exerted by the aligners on the teeth and the areas on which these pressures are applied were considered. Results showed that pressures exerted by the aligner are not uniformly distributed over the entire surface of the tooth and that, for different aligners made on the same model, the areas of forces application were not identical, since they were influenced by factors resulting from the production processes. A second study investigated the dimensional stability of the aligners after applying dynamic stress in vivo and static stress in vitro. Three different materials typically used for making the aligners (PET-G, PET and SmartTrack®) were tested. The effects of dynamic stress produced in vivo were evaluated by having a patient wear the three different aligners over a two-week period. The effects of static stress were assessed by subjecting the aligners to a static load using a testing machine. The tested aligners were scanned and measured, in order to evaluate their dimensional stability after different types of stress. Results showed that the PET aligners appeared to have the lowest deformation percentage, while the PET-G and SmartTrack® aligners showed a reduced deformation going from the back to the front area. Finally, contact with human saliva seemed to induce greater deformation.

INTRODUCTION: Les gouttières thermoplastiques orthodontiques doivent souvent être retirées par les patients avant de consommer des aliments ou des liquides autres que l’eau. Cette précaution évite notamment des changements de couleur au niveau du matériau les constituant. Des études antérieures ont concentré leurs recherches sur des changements de coloration chez des marques limitées d’aligneurs thermoplastiques en excluant certaines marques américaines populaires. OBJECTIFS: L’objectif principal de cette étude vise à évaluer la résistance au changement de teinte du polymère formant trois différentes marques d’aligneurs américaines. Un but secondaire est de comparer le pouvoir de retrait de taches de deux produits nettoyants conçus pour ces appareils amovibles. Un but tertiaire est d’évaluer le type de polymère qui constitue les surfaces interne et externe de chaque marque étudiée de gouttières. MATÉRIELS ET MÉTHODES : Les gouttières ont été exposées à l’un des divers liquides colorants de l’alimentation courante (thé, café, vin rouge et cola) ou à une solution de contrôle formée d’un gel de remplacement salivaire Biotène® Oral Balance. Les trois marques évaluées étaient Invisalign®, ClearCorrect® et Minor Tooth Movement®. Après leur immersion de douze heures ou de sept jours, les mêmes gouttières étaient nettoyées pendant quinze minutes avec soit les cristaux Invisalign®, soit le bain Cordless Sonic Cleaner combiné avec un comprimé Retainer Brite®. Les données de colorimétrie étaient obtenues à l’aide d’un numériseur calibré et du logiciel Adobe Photoshop® en utilisant l’espace chromatique CIELAB pour comparer les changements de coloration (E) entre les divers moments à l’étude. Les paramètres L*, a*, b* étaient mesurés au temps initial (T0), après douze heures d’immersion (T1), après sept heures d’exposition (T2) et après nettoyage (T3). Les deltas E étaient ensuite convertis en unités du National Bureau of Standards (NBS) pour faciliter l’interprétation clinique des données. Selon la section, les analyses statistiques employées (test de Levene, ANOVA, méthode de Brunner-Langer, test de Tukey ou test-t) permettaient d’évaluer les interactions entre les trois marques entre elles ou entre les marques et les nettoyeurs. Une valeur de p < 0,05 était considérée statistiquement significative. RÉSULTATS ET DISCUSSION: Les résultats suggèrent qu’une exposition de douze heures au café pour les aligneurs Invisalign® engendre un changement de couleur statistiquement significatif par rapport aux deux autres marques. Il en est de même pour une durée identique d’immersion dans le vin rouge ; les coquilles Invisalign® présentent un changement de teinte statistiquement significatif par rapport à ses compétiteurs. Après sept jours d’exposition au café ou au vin rouge, les coquilles de la marque Invisalign® ont aussi des changements de coloration statistiquement significatifs par rapport aux deux autres marques, mais plus prononcés qu’après douze heures. Le thé noir engendre des changements de couleur importants au niveau clinique chez les trois marques après sept jours d’exposition sous forme de taches extrinsèques. Les deux méthodes de nettoyage étudiées présentent un potentiel clinique de retrait de taches accru pour celles extrinsèques du thé noir par rapport aux taches intrinsèques des autres solutions étudiées. Les résultats par spectrophotométrie à lumière infrarouge démontrent des spectres similaires pour les surfaces interne et externe de chaque marque. Or, ce n’est pas le même polymère qui est employé par chaque compagnie. Des spectres ATR-FTIR d’un matériau à base de polyuréthane sont observés pour les marques Invisalign® et ClearCorrect®. Des spectres ATR-FTIR de matériau à base de polyéthylène téréphtalate glycolisé sont plutôt représentatifs de la marque Minor Tooth Movement®. CONCLUSION: Les aligneurs de la compagnie Invisalign® sont plus susceptibles de souffrir de pigmentation par le café et le vin rouge que les deux autres marques qui ont présenté une stabilité accrue de leur coloration au contact de ces solutions. Le thé a engendré des changements de couleur extrinsèques importants chez les trois marques étudiées.
INTRODUCTION: Manufacturers of orthodontic aligners suggest that users take off removable appliances every time they consume solid foods or any drink (except water). This is to avoid a color change within the clear thermoplastic material of which they are made. Prior studies have focused on a limited set of aligners, excluding some popular American brands on the market. OBJECTIVES: The main objective of this study is to evaluate the stain resistance of the polymer forming three different American aligner brands. A secondary aim is to evaluate the stain-removal potential of two cleaning techniques for these devices. A tertiary goal is to determine the type of polymer forming the internal and external surfaces of the studied brands of aligners. MATERIALS AND METHODS: The removable appliances were exposed to different staining agents common in a regular diet (coffee, red wine, black tea and cola) or to a control solution made of a Biotene® Oral Balance saliva replacement gel. The three brands evaluated were Invisalign®, ClearCorrect® and Minor Tooth Movement®. Following exposure, the same aligners were cleaned during fifteen minutes with either the Invisalign® cleaning crystals or the Cordless Sonic Cleaner combined with a Retainer Brite® tablet. Colorimetry data was acquired via a calibrated scanner and the Adobe Photoshop® software, using a CIELAB color space approach to compare color changes (E) in aligners exposed to various media. The CIE color parameters (L*, a*, b*) of each specimen were measured before immersion (T0), after a twelve-hour exposure (T1), after a seven-day exposure (T2) and after cleaning (T3). Those color differences were then converted into National Bureau of Standards (NBS) units to facilitate the clinical interpretation. Statistics methods (Levene’s test, ANOVA, Brunner-Langer model, Tukey’s range test and t-test) were used to identify interactions between the brands themselves or between the brands and the cleaning methods. A p value < 0.05 was considered statistically significant. RESULTS AND DISCUSSION: This study suggests that an exposure of twelve hours to instant coffee affects significantly the color of the Invisalign® aligners compared to the two other brands. A twelve-hour immersion into red wine also causes a statistically significant color change for the Invisalign® devices compared to their competitors. After seven days of exposure, a more conspicuous intrinsic color change is observed in the Invisalign® aligners exposed to instant coffee and red wine. In both media, the results are statistically significant for the Invisalign® appliances compared to the ClearCorrect® and the Minor Tooth Movement® aligners. The black tea creates an important extrinsic color change in the three brands after seven days. While normal exposure conditions would not typically consist of 12 h to 7 days of continuous exposure, these data indicate that repeated, cumulative exposure may be problematic. The two cleaning methods tend to show a better efficacy in removing extrinsic stains from black tea compared to intrinsic stains of other substrates. The infrared spectrophotometry confirms that the internal and external surfaces of each studied brand of aligners were made of the same polymer. ATR FTIR spectra of polyurethane-based material are observed for the Invisalign® and the ClearCorrect® devices. However, for the Minor Tooth Movement® aligners, the ATR FTIR analysis shows that the appliances are a polyethylene glycol terephthalate polyester. CONCLUSION: The Invisalign® aligners were more prone to pigmentation from coffee and red wine than the ClearCorrect® or the Minor Tooth Movement® devices. Black tea caused important extrinsic stains on the surface of the three tested brands.

Objective: To compare the periodontal health of patients treated with conventional fixed appliance and patients treated with clear aligner systems, in various malocclusions. Methods: A systematic literature search comprised three databases: PubMed, B-on and Cochrane. Eligible studies were selected based on the inclusion and exclusion criteria. Results: Seven studies were selected for data extraction, three randomized controlled trials and four cohort studies. The total number of participants making up this systematic review was 390. The plaque index showed a statistically significant differences between patients with fixed orthodontic appliances and clear aligners while the others indices showed no statistically significant differences. Conclusion: This review didn’t found data that support the existence of significant statistic differences between clear aligners and fixed orthodontic appliances regarding periodontal health impact. More studies are needed to clarify this aspect related with the orthodontic treatment.
Objetivo: Comparar o status periodontal dos pacientes tratados com aparelhos ortodônticos fixos convencionais e o status periodontal dos pacientes tratados com aparelhos removíveis comummente designados alinhadores, em diferentes más oclusões. Metodologia: Foi realizada uma revisão sistemática da literatura, nas fontes electrónicas de informação seguintes: PubMed, B-on e Cochrane. Foram definidos critérios de inclusão e de exclusão que permitiram a seleção dos artigos analisados no trabalho. Resultados: Foram selecionados sete artigos para revisão, dos quais três respeitavam a ensaios clínicos randomizados controlados e quatro a estudos de coorte. O número total de participantes incluídos nesta revisão foi de 390 indivíduos. A análise dos dados relativos aos índices de placa bacteriana dos pacientes revelam diferenças estatisticamente significativas entre os dois grupos estudados, enquanto na análise dos restantes índices periodontais não se detectam diferenças estatisticamente significativas. Conclusão: Este trabalho não encontrou evidência científica que permita concluir que existem diferenças estatisticamente significativas relativas ao estado de saúde dos tecidos periodontais dos pacientes tratados ortodonticamente, em função do tipo de aparelhos analisados neste estudo. Sugere-se a realização de novas investigações para melhor clarificação deste assunto.

碩士
逢甲大學
纖維與複合材料學系
105
The advantages of using transparent and invisible braces as orthodontic aligner material were due to its properties of beautiful, comfortable, health, security and other advantages and therefore, they have been widely used. The thermoplastic polyester PETG as matrix material, which was modified by blending research and led to excellent comprehensive properties of orthodontic materials, were preparated. We explore the comparison with commercially available stealth orthodontic materials. In this experiment, PETG, PC and TPU were mixed according to respective different proportion of 80/10/10, 65/10/25, and 50/10/40 weight percentages. The matrix blended at different melting temperature of 200℃ and 210℃for mixing. The mixtures as experimental groups and commercialized orthodontic materials as compared group were studied. Through the experiment discovered: When the PETG content in the mixture is 80%, the blend and tensile strength are closest to each other orthodontic material. Orthodontic material tensile strength is 590MPa. The more PETG content in the blend and Orthodontic material tensile sections are rigid fracture. The more TPU content in the blend is higher the brightness. The largest brightness L is at the value of 87.77. Blend with the contact angle of 67ﾟ~78ﾟ，shows the blend has the relative hydrophobic property. The commercialized orthodontic material of CA has a water absorb rate of 0.37% after 336 hours of immersion, The PPT blend has a water absorption of 0.3 to 0.32% after 336 hours of immersion. DSC：The masured glass temperature of Blends conversion point is 68 ~ 75℃that is consisted of the commercialized orthodontic materials CA with glass temperature of conversion point 75.84℃. Both glass temperatures are quite close to the point of theoretical conversion. Normal diet will not cause too much impact on the stealth appliance, thus it will not cause material melting.

The newly emerging Clarity™ Clear Aligner System from 3M has set out to address one of the biggest pitfalls of thermoplastic aligners: accuracy of orthodontic movements. The 3M Clarity™ Clear Aligner System is unique among clear aligners because it employs a proprietary, sophisticated machine-learning algorithm to design orthodontic movement schematics. The core of the Clarity™ Aligner System is artificial intelligence, meaning that a prospective analysis of preliminary data is essential for the development and improvement of the accuracy of the algorithm. This study investigates movement and accuracy of the Clarity™ Aligner System, from a preliminary data subset from ongoing prospective, randomized clinical trials. Movement from the first trial subset is examined in terms of the following movement factors: secondary premolar-secondary premolar (5+5 in the Palmer system) arch expansion or crowding resolved, absolute rotation, absolute mesial-distal tipping, and absolute torque for both the crown and root. These movements are further examined according to specific tooth types. Both actual observational orthodontic movements and theoretical movements are designed by the Clarity™ System. The accuracy of actual movement in terms of theoretical movements is calculated; however, it is impossible to calculate the significance of these accuracies due to a complete lack of benchmark movement values for the clear aligner market. There are no benchmark values to compare to, so orthodontic movements will be critically examined for performance, and casually compared to alternative aligner systems. Identifying potential weaknesses in the Clarity™ Aligner System is imperative for maximizing its effectiveness.

Objetivo: Identificar estudos na literatura científica comparando o fundamental da saúde periodontal em pacientes que usam aparelhos ortodônticos fixos e alinhadores transparentes. Métodos: Foi realizada uma pesquisa bibliográfica integrativa através de diferentes bases de dados, Pubmed e a Biblioteca Cochrane. Este trabalho foi submetido a uma estratégia de pesquisa seguindo o método PICO. Resultados: 8 estudos foram elegíveis para esta revisão integrativa. E numerámos 204 pacientes tratados com alinhadores e 294 com aparelhos ortodônticos fixos principalmente braquetes elastoméricos ligados. Apenas o Índice de Placas mostrou uma diferença significativa entre os 2 grupos. Conclusão: São necessários mais estudos para afirmar que os alinhadores são sinónimo de melhores condições gengivais em comparação com os pacientes tratados com aparelhos fixos. Outros actores, tais como instruções de higiene oral, motivação e tratamento de suporte tendem a ser mais prevalecentes do que o tipo de aparelho em si na avaliação periodontal.
Objective: To identify studies in the scientific literature comparing the fundamental of periodontal health in patients wearing fixed orthodontic appliances and transparent aligners. Methods: An integrative literature search was performed through different databases, Pubmed and the Cochrane Library. This work was submitted to a search strategy following the PICO method. Results: 8 studies were eligible for this integrative review W e enumerated 204 patients treated with aligners and 294 with fixed orthodontic appliances mainly elastomeric ligated brackets. Only the Plaque Index displayed a significant difference between the 2 groups. Conclusion: More studies are necessary to affirm that aligners is synonym of better gingival conditions in com parison with patients treated with fixed appliances. Others actors such as oral hygiene instructions, motivation and supportive treatment tend to be more prevalent than the type of appliance itself in the periodontal evaluation.

Aims: To compare the initial discomfort between the two orthodontic methods, with pain measurements, control of the frequency of taking analgesics, and changes in daily routine. Materials and methods: The article searches were mainly carried out on the Pubmed and ResearchGate websites, using the following keywords: "invisalign", "fixed appliance", "pain", "analgesics", "discomfort", "impact on daily performance", in addition to an in-depth study of the bibliographies. Results: Eight studies were deemes relevant to our work. Conclusion: With a lower certainty, the pain in patients using aligners seems to be less intense than in patients with fixed applainces and the use of analgesic is therefore more important for the fixed group. These two parameters follow a gradual decrease during the first week of treatment. Chewing, speaking and general activity can be affected by the treatment.
Objetivos: Comparar o desconforto inicial entre os dois métodos ortodônticos, com medições da dor, controlo da frequência da toma de analgésicos e alterações da rotina diária. Materiais e métodos: As pesquisas de artigos foram realizadas principalmente nos sites Pubmed e ResearchGate, utilizando as seguintes palavras-chave: "invisalign", "aparelho fixo", "dor", "analgésicos", "desconforto", "impacto no desempenho diário", para além de um estudo aprofundado das bibliografias. Resultados: Oito estudos foram considerados relevantes para o nosso trabalho. Conclusão: Com uma certeza menor, a dor nos pacientes que utilizam alinhadores parece ser menos intensa do que nos pacientes com maçãs fixas, pelo que a utilização de analgésicos é mais importante para o grupo fixo. Estes dois parâmetros seguem uma diminuição gradual durante a primeira semana de tratamento. A mastigação, a fala e a actividade geral podem ser afectadas pelo tratamento.

INTRODUCTION Il existe actuellement de nombreuses options esthétiques de traitement pour corriger orthodontiquement les malocclusions dentaires. Le standard de traitement en chirurgie orthognatique est d’utiliser des boîtiers conventionnels fixes. Récemment, une nouvelle technique gagne en popularité en pratique privée : l’utilisation de coquilles d’alignement transparentes comme alternative esthétique. La littérature actuelle sur ce sujet consiste exclusivement de rapports de cas. Ainsi, il semble raisonnable d’affirmer que davantage de recherche est nécessaire sur ce sujet. OBJECTIFS L’objectif principal de cette étude rétrospective est d’évaluer la qualité des résultats obtenus à la suite de traitements combinés d’orthodontie et de chirurgie orthognatique en utilisant le système Invisalign®, en comparaison avec les boîtiers orthodontiques traditionnels. L’objectif secondaire de comparer la durée de traitement entre les deux systèmes. MATÉRIEL/MÉTHODES Quarante-neuf patients ont été recrutés en provenance de deux pratiques orthodontiques privées (24 Invisalign® / 25 contrôles de boîtiers fixes). Les deux groupes étaient initialement similaires, tel que mesuré par le Discrepancy Index de l’American Board of Orthodontics. Les résultats finaux ont été évalués en utilisant l’outil Phase III (Model Grading System) de l’American Board of Orthodontics. RÉSULTATS Les scores moyens de chaque catégorie du Model Grading System étaient supérieurs pour le groupe Invisalign® et une différence significative existait entre les groupes pour les catégories d’alignement, de contacts occlusaux, d’angulation des racines et de score total. Les durées de la préparation pré-chirurgicale et du traitement total se sont révélées plus courtes pour le groupe Invisalign® (p ≤ 0.05). CONCLUSION Invisalign® a produit des traitements combinés d’orthodontie et de chirurgie orthognatique plus courts que les boîtiers traditionnels. Par contre, des scores du Model Grading System supérieurs ont été répertoriés lorsque comparés avec les boîtiers conventionnels, signifiant la production de résultats de qualité inférieure à la technique traditionnelle fixe.
INTRODUCTION Numerous esthetic orthodontic treatment options currently exist to correct dental malocclusions. The gold standard in orthognathic surgery is to use bonded orthodontic brackets. Recently, clear aligners have been proposed as an alternative. The current available literature on this topic consists exclusively of case reports. Therefore, it seems reasonable to assume that further research is needed on this topic. OBJECTIVE The primary objective of this retrospective study aims to evaluate the quality of the outcomes of combined orthodontic and surgical treatments with Invisalign® when compared with conventional orthodontic treatments. The secondary objective is to compare the duration of treatment between Invisalign® and conventional brackets. MATERIAL/METHODS Forty-nine patients were recruited from two orthodontic private practices (24 Invisalign® / 25 bracket controls). Both groups were initially similar, as per the ABO Discrepancy Index. The results were assessed using the ABO Phase III method (MGS). RESULTS The MGS mean scores were consistently higher for Invisalign® and there was a significant difference between the groups regarding alignment, occlusal contacts, root angulations and total score. The duration of pre-surgical preparation and the total treatment time were shorter for the Invisalign® group (p ≤ 0.05). CONCLUSION Invisalign® provided faster combined orthodontic and orthognathic surgery treatment, yet demonstrated inferior quality of results when compared to conventional brackets using the MGS.

Objectif: Suite aux traitements avec aligneurs, une insuffisance de contacts postérieurs est souvent notée cliniquement: existe-t-elle réellement, se corrige-t-elle spontanément? Cette étude vise à comparer la qualité de l’occlusion statique chez des patients ayant été traités avec boitiers conventionnels ou par aligneurs, dès la dépose des appareils orthodontiques et après six mois de mise en place fonctionnelle. Matériel and Méthodes: La mise en place fonctionnelle de l’occlusion chez des sujets traités par boitiers conventionnels (GB, n=25) ou par aligneurs (GA, n=14) et par a été évaluée par un système d’analyse occlusale informatisée (T-scan 9), au moment de la dépose (T0), puis à 3 et 6 mois de contention (T3 et T6). Les sujets (41% de filles, âge moyenne de 19,38 ± 5,98 ans), étaient traités sans extractions, ni chirurgie, avec pour contention des fils collés ou appareils sans recouvrement occlusal. La symétrie et la simultanéité des contacts ainsi que la position antéro-postérieure du centre de forces (CF) étaient évalués. Résultats : À tout moment (T0, T3, T6), aucune différence statistiquement significative n’a été observée quant à la position antéro-postérieure du CF (p=0,854), la répartition ou la simultanéité des contacts, quelle que soit la modalité de traitement. Le CF était situé antérieurement chez les patients de sexe féminin à tout temps (p=0,002). La mise en place fonctionnelle semblait être terminée dès trois mois pour les deux groupes. Conclusion: La qualité de l’occlusion était comparable dans les deux groupes six mois après la dépose des appareils orthodontiques, signifiant l’absence d’influence du type de traitement à court terme. Le sexe féminin pourrait être associé à un CF plus antérieur même après six mois de mise en place fonctionnelle.
Objective: Following aligner therapy, a lack of posterior contacts is common and is expected to resolve with settling. The aim of the study was to compare the quality of occlusion and settling, immediately after treatment and during a retention period of six months, in patients treated with fixed appliance therapy or clear aligners. Materials and Methods: 25 patients treated with fixed appliances and 14 patients treated with aligners were evaluated by a digital occlusal analysis (T-Scan 9) at time of debonding (T0) and 3 and 6 months later (T3 and T6). Subjects (41% female, average age 19.38 ± 5.98) were treated without extraction or maxillofacial surgery using either bonded wires or removable appliances without occlusal coverage as retainers. Contact symmetry, simultaneity and the antero-posterior position of the Center of Force (COF) were assessed at the time of debonding, and after 3 and 6 months of retention. Results: At all times of evaluation, the COF position was not statistically different for both treatment modalities (p=0.854), but was located more anteriorly in female patients when compared to male patients (p= 0.002). Settling appeared to be completed by 3 months in both groups. Conclusion: The quality of the occlusion was comparable after 6 months of settling when treated with either treatment modality indicating no short-term effect of treatment type. Females maintained a more anterior COF after six months of retention.

Objetivos: Avaliar as diferenças entre médicos dentistas generalistas e ortodontistas na seleção e no tratamento ortodôntico efetuado com alinhadores transparentes, a sua experiência profissional neste domínio, a sua confiança na seleção dos pacientes, bem como as motivações para a não escolha deste tipo de tratamento. Métodos: Foi elaborado um questionário dirigido a médicos dentistas generalistas e ortodontistas, para comparação de experiência em tratamento com técnicas de alinhadores. Foi considerado um erro tipo I de 0,05. Resultados: Do total de inquiridos, observou-se um maior período cumulativo de formação pós-graduada superior para os ortodontistas, comparativamente aos médicos dentistas generalistas (p < 0,001), assim como maior utilização de técnicas de alinhadores (84,5% vs. 25,0%, p < 0,001). Os ortodontistas referem tratar maior grau de apinhamento (p = 0,001), associando com maior frequência técnicas auxiliares ao uso de alinhadores (90,1% vs. 47,1%; p < 0,001). Dos participantes que não realizam tratamento com alinhadores, a causa mais reportada foi a ausência de experiência, com mais ortodontistas a demonstrar intenção de utilizar a técnica no futuro (92,3% vs. 50,0%; p = 0,006). Conclusões: Os ortodontistas têm um maior número de anos de formação pós-graduada e utilizam com maior frequência tratamentos com técnicas de alinhadores do que os médicos dentistas generalistas, com maior utilização de técnicas auxiliares e tratamento de apinhamento de maior grau. Os médicos dentistas que não usam alinhadores são mais jovens, com menos experiência profissional e formação pós-graduada, apontando como causa para a não utilização a falta de experiência.
Aim: Assess differences between general practitioner dentists and orthodontists, regarding the use of clear aligner treatment, patient selection, professional expertise and confidence in their technique, as well as defining the reasons for not treating with clear aligners. Methods: A query was created and sent to general practitioner dentists and orthodontists, in order to compare their experience with clear aligner treatment. A type I error of 0.05 was considered for all comparisons. Results: Of all the surveyed participants, a higher cumulative period of post-graduate training was observed for orthodontists comparing to general practitioners (p < .001), with higher rate of clear aligner usage (84,5% vs. 25,0%, p < .001). Orthodontists treat higher crowning (p = .001) and associate auxiliary techniques to clear aligners more often (90.1% vs. 47.1%; p < .001). Considering participants who do not use aligners, the main reason for not using the technique was lack of experience, with orthodontists more prone to use technique in the future than general practitioners (92,3% vs. 50,0%; p = .006). Conclusion: Orthodontists have longer post-graduate education and use clear aligners more often than general practitioners, treating higher crowning and using more concomitant techniques. Dentists who do not use aligners are younger and less experienced, and do not use clear aligners due to lack of experience.

Esta dissertação tem o objetivo de analisar os alinhadores como forma de tratamento em ortodontia. É feita uma abordagem sobre a evolução destes dispositivos e quais as possíveis soluções atuais para com os mesmos elaborar correções ortodônticas. São abordadas algumas das correções de posição que eram consideradas problemáticas e de difícil resolução recorrendo a alinhadores, mas que, com desenvolvimentos mais recentes, já se tornou possível fazê-lo. As problemáticas abordadas são a mordida aberta, a mordida profunda, o fechamento de espaços, a mordida cruzada, a extrusão, a Correção de classes II e a Correção de classes III. Foi realizado um levantamento das principais vantagens e limitações dos alinhadores em relação à ortodontia fixa convencional.
The objective of this dissertation is analysing the use of clear aligners as treatment in orthodontics. For this purpose was made an approach about the evolution of this orthodontic devices and which are the most recent and possible solutions we can use to achieve certain orthodontic corrections. This dissertation will also focus in certain orthodontic corrections that have been made possible with recent developments, but not long ago were problematic and difficult to resolve with clear aligners, the issues addressed are openbite, deepbite, space clousure, crossbite, extrusion, class II correction and class III correction. Furthermore was made an analysis on the main advantages and limitations of clear aligners when compared with conventional fixed appliances.

Objectif: L'objectif primaire de cette étude était d'évaluer la validité, la fiabilité et la reproductibilité des mesures dentaires obtenues sur les modèles digitaux iTero (Align Technology, San Jose, Californie) et Unitek TMP Digital (3M, Monrovia, Californie) en comparaison avec celles obtenues sur les modèles de plâtre (gold standard). L'objectif secondaire était de comparer les deux différents matériaux à empreinte (l'alginate et le polyvinylsiloxane-PVS) afin de déterminer si le choix du matériau affectait la précision des mesures. Méthodes: Le premier volet de l'étude impliquait les modèles digitaux Unitek et iTero, obtenus à partir de 25 paires de modèles de plâtre choisis de façon randomisée et provenant de la pratique privée d'un des co-auteurs. Des empreintes d'alginate et de PVS ont été prises sur les modèles de plâtre et numérisées par le scanner Unitek. Les modèles ont ensuite été numérisés avec le scanner iTero. Le deuxième volet de l'étude cherchait à comparer les modèles digitaux iTero (numérisation intra-orale) avec les modèles de plâtre (empreintes d'alginate et de PVS) obtenus à partir de 25 patients de la clinique d'orthodontie de l'Université de Montréal ayant besoin d'un traitement orthodontique. Dans les deux volets de l'étude, deux auteurs ont pris les mesures suivantes sur les différents modèles: largeur mésio-distale de chaque dent de la première molaire à l'autre première molaire, le périmètre d'arcade, les distances intermolaire et intercanine, le surplomb vertical et le surplomb horizontal. Les ratios et excès Bolton 6 et 12, l'espace requis et les différentiels d'espace au maxillaire et à la mandibule, ont été calculés. Résultats: La fiabilité (ICC) entre les modèles digitaux (Unitek et iTero) et les modèles de plâtre était bonne à excellente pour toutes les mesures [ICC=0,762–0,998], et la fiabilité entre les deux matériaux à empreinte était excellente [ICC=0,947–0,996]. Dans les deux volets de l'étude, les mesures faites sur les modèles iTero étaient généralement plus grandes que celles faites sur les modèles de plâtre. Les plus grandes différences moyennes pour la comparaison iTero-plâtre étaient trouvées au niveau de l'espace disponible au maxillaire et à la mandibule (systématiquement plus grande pour cette variable), soit 2,24 mm et 2,02 mm respectivement dans le premier volet, et 1,17 mm et 1,39 mm respectivement dans le deuxième volet. Les différences étaient considérées cliniquement non significatives pour toutes les variables. La reproductibilité intra-examinateur était bonne à excellente pour les modèles de plâtre et les modèles digitaux, à l'exception du différentiel d'espace à la mandibule pour les modèles Unitek [ICC=0,690-0,692]. La reproductibilité inter-examinateur était bonne à excellente pour les modèles de plâtre et les modèles digitaux dans les deux volets de l'étude, mais acceptable à modérée pour les modèles Unitek au niveau des analyses Bolton 6 et 12, et des différentiels d'espace au maxillaire et à la mandibule [ICC=0,362-0,548]. Conclusions: La précision et la fiabilité des mesures dentaires faites sur les modèles digitaux Unitek et iTero étaient cliniquement acceptables et reproductibles en comparaison avec les celles faites sur les modèles de plâtre. Le choix de matériel à empreinte entre l'alginate et le PVS n'affectait pas la précision des mesures. Cette étude semble démontrer que les modèles digitaux Unitek et iTero, utilisés avec leur logiciel respectif, sont une alternative fiable et reproductible aux modèles de plâtre pour le diagnostic et l’analyse des modèles orthodontiques.
Objective: The primary objective of this study was to evaluate the validity, reliability and reproducibility of dental measurements obtained on digital models produced by iTero (Align Technology, San Jose, California) and by Unitek TMP Digital (3M, Monrovia, California) in comparison with those obtained on plaster models (gold standard). The secondary objective was to compare two different impression materials (alginate and polyvinylsiloxane-PVS) to determine whether the material used affects accuracy of the measurements. Methods: The first part of the study involved Unitek and iTero digital models, which were all obtained from 25 pairs of plaster models randomly selected from one of the co-author's private practice. Alginate and PVS impressions were taken on plaster models and were scanned by the Unitek scanner. The same models were then scanned with the iTero scanner. The second part of the study sought to compare iTero digital models (intraoral scans) with plaster models (alginate and PVS impressions) taken on 25 patients requiring treatment from the Orthodontic clinic of the University of Montreal. In both parts of the study, two authors took the following measurements on the different models: mesio-distal width of each tooth from first molar to the other first molar, intermolar and intercanine distances, overbite and overjet. Bolton 6 and 12 ratios and excesses, maxillary and mandibular space available and required were also calculated in order to determine space differentials. Results: A good to excellent reliability (ICC) was found for all measurements when comparing digital (Unitek and iTero) and plaster models [ICC=0.762–0.998], and excellent reliability when comparing both impression materials [ICC=0.947–0.996]. In the two parts of the study, measurements on iTero models were generally larger than on plaster models. Highest mean differences for iTero-plaster were found for maxillary space available and mandibular space available (systematically larger for that variable): 2.24 mm and 2.02 mm respectively in the first part of the study, 1.17 mm and 1.39 mm respectively in the second part. Differences were considered clinically insignificant for all variables. Intraexaminer reproducibility was good to excellent for plaster and digital models, except for mandibular space differential on Unitek models [ICC=0.690-0.692]. Interexaminer reproducibility was good to excellent for plaster and digital models in both parts of study, but fair to moderate for Unitek models regarding Bolton 6 and 12, and maxillary and mandibular space differentials [ICC=0.362-0.548]. Conclusions: The accuracy and reliability of dental measurements done on Unitek and iTero digital models were clinically acceptable and reproducible when compared with measurements done on traditional plaster models. The choice of impression material between alginate and PVS did not affect accuracy of the measurements. This study tends to indicate that Unitek and iTero digital models examined with their associated software can be reliably used for orthodontic cast analysis and diagnosis.

Os sistemas de alinhadores surgiram como uma das opções possíveis para o tratamento ortodôntico de pacientes mais exigentes no que concerne à estética. Graças ao desenvolvimento destes dispositivos e uma maior procura por parte dos pacientes, os tratamentos com alinhadores têm evoluído significativamente com o objetivo de atingir resultados semelhantes aos obtidos com os tratamentos convencionais com brackets, particularmente em casos mais complexos em adultos e adolescentes. O objetivo deste trabalho, através de uma revisão bibliográfica, é comparar tratamentos ortodônticos com aparatologia fixa (brackets) com os realizados com dispositivos removíveis (alinhadores).
The aligners system have emerged as one of the possible options for orthodontic treatment of more demanding patients with concerns to aesthetics. With the development of these appliances and increased patient demand, treatments with aligners have significantly evolved with the goal of achieving similar results to those obtained with the conventional bracket treatments, particularly in more complex cases in adults and adolescents. The aim of this paper, through a bibliographical review, is to compare orthodontic treatments with fixed appliances (brackets) with removable appliances (aligners).