Factors related to the control of maxillary anterior teeth torque in invisible appliances / 口腔疾病防治

@#Invisible appliance technology is a novel orthodontic technology that uses computer aided design and polymer materials to achieve a more aesthetic and comfortable treatment. Compared with traditional lip-bracket orthodontic treatments, the greatest advantages of an invisible appliance are aesthetics. In the orthodontic process, the control of the anterior teeth may not be accurate, which often directly affects the patient′s postoperative side appearance; however, in clinical practice, there is still a large deficiency in the control of the anterior tooth torque by an invisible appliance compared to traditional lip-bracket orthodontic treatments. The factors related to the expression efficiency of anterior tooth torque include the combination of morphology and position of different types of brackets and wires, the tooth movement mode and clincheck design. This article reviews the factors that influence lingual orthodontics and clear aligner therapy in the treatment of anterior tooth torque.

Application of an individualized appliance in orthodontic treatment / 口腔疾病防治

@#More than 20 years have passed since the advent of individualized appliances, which are designed according to the corrective target position. Through a series of digital technology-aided design and production processes, individual appliances have been increasingly recognized and accepted by the public. At present, there are three types of individualized orthodontic appliances: individualized lingual orthodontic appliances, non-bracket invisible appliances and individualized labial appliances. Because of their good effects in orthodontics, these appliances have gradually become mainstream orthodontic treatment tools. However, many doubts persist regarding their use in clinical treatment. This article reviews the development history, design principles and characteristics of the three types of individualized appliances. The results of a literature review showed that CAD/CAM and CBCT provide a hardware foundation for personalized orthodontic appliances that simplifies the therapeutic process. Additionally, individualized appliances also place higher demands on orthodontists. This article could provide references for and help with the clinical selection and use of individualized appliances.

Application of digital technology in orthodontic clinic / 口腔疾病防治

@#The rapid development of digital technology has made the processes of orthodontic data collection, diagnosis, design and treatment more accurate, comprehensive, convenient and safe and has improved the clinical efficiency of orthodontists. Safe, non-invasive, rapid three-dimensional facial imaging and digital dental models have enabled orthodontists to collect accurately visualized case data. In addition, during diagnosis and design, orthodontists can comprehensively analyze teeth, jaws, and cranial surfaces in 3 dimensions. Through advances that range from digitized whole-dentition information to computer-replicated design and computer-aided manufacturing, invisible orthodontic technology without brackets has become one of the best manifestations of the combination of digital technology and oral orthodontics. In addition, individualized fixed orthodontic devices have become widely used in orthodontic clinics. In this paper, the applications of digital technology in orthodontic clinics is described. It is hoped that orthodontists will be able to use digital technology rationally to benefit increasing numbers of patients with orthodontic demands.

Biomechanical analysis of micro-implants lingual straight wire appliance during retracting maxillary anterior teeth / Análisis biomecánico de microimplantes con dispositivo de alambre recto lingual durante la retracción de dientes maxilares anteriores

This study aimed to establish three-dimensional finite element models of micro-implants-lingual straight wire appliance and to investigate the effects of different wire patterns on the initial displacement of the maxillary anterior teeth and the stress of the periodontal ligament and tooth root during retracting maxillary anterior teeth in lingual orthodontics. A three-dimensional geometric models of maxilla with maxillary dentition was established using Cone-beam CT scan .Three types of maxilla models including microimplants and Duet-Slot Lingual Bracket appliance with three different arch wires ( model A: 0.016 inch × 0.022 inch stainless steel square wire; modelB: 0.016 inch stainless steel round wire; model C: double wire of 0.016 inch × 0.022 inch stainless steel square wire + anterior teeth 0.016 inch stainless steel round wire) were assembled by Unigraphics NX 8.5 software. The labial intrusion force and lingual retraction force were simulatively loaded to obtain initial displacement of the anterior teeth and the stresses of each tooth root and periodontal ligament, using three-dimensional finite element calculation software Ansys Workbench 15. The initial displacement of the lateral incisors was close to the bodily movement; and central incisors and lateral incisors slightly extruded. Compared with group A and group C, canine teeth appeared obviously horizontal "arched effect" by crown labial tipping in group B. The stress distribution of the tooth root and periodontal ligament was minimal and uniform in the group C. The 0.016 × 0.022- in stainless steel rectangular wire combined with 0.016- in stainless steel round wire used in the anterior teeth can better control the torque of the maxillary anterior teeth for space close in lingual orthodontics. Moreover, the stress distribution of tooth root and periodontal ligament is even, which is difficult to damage the periodontal ligament or result in external resorption of tooth root.

Este estudio tuvo como objetivo establecer modelos tridimensionales de elementos finitos de microimplantes linguales de alambre recto e investigar los efectos de diferentes patrones de alambre en el desplazamiento inicial de los dientes maxilares anteriores y el estrés del ligamento periodontal y la raíz del diente durante la retracción lingual sobre los dientes anteriores del hueso maxilar en ortodoncia. Se establecieron modelos geométricos tridimensionales del hueso maxilar con dentición utilizando una exploración por tomografía computarizada de haz cónico. Tres tipos de modelos maxilares, incluidos los microimplantes y el dispositivo Duet-Slot Lingual Bracket con tres arcos diferentes (modelo A: 0.016 pulgada × 0.022 pulgada alambre cuadrado de acero inoxidable; modelo B: alambre redondo de acero inoxidable de 0.016 pulgadas; alambre cuadrado de acero inoxidable de 0.016 pulgada × 0.022 pulgada y alambre redondo de acero inoxidable de 0.016 pulgada) ensamblados por el software Unigraphics NX 8.5. La fuerza de intrusión labial y la fuerza de retracción lingual se cargó simultáneamente, para obtener el desplazamiento inicial de los dientes anteriores y las tensiones de cada raíz dental y ligamento periodontal, usando el software tridimensional de cálculo de elementos finitos Ansys Workbench 15. El desplazamiento inicial de los incisivos laterales se relacionaba al movimiento corporal; mientra que los incisivos centrales e incisivos laterales se mostraron ligeramente extruidos. Comparado con el grupo A y el grupo C, los dientes caninos presentaron un "efecto arqueado" horizontal por la inclinación labial de la corona en el grupo B. La distribución del estrés de la raíz del diente y el ligamento periodontal fue mínima y uniforme en el grupo C. El alambre rectangular de acero inoxidable combinado con el alambre redondo de acero inoxidable de 0.016 usado en los dientes anteriores puede controlar mejor el torque de los dientes maxilares anteriores para cerrar el espacio en ortodoncia lingual. Además, la distribución del estrés de la raíz del diente y del ligamento periodontal es pareja, lo que dificulta dañar el ligamento periodontal o provocar una resorción externa de la raíz del diente.

The effect of occlusogingival placement of clinical bracket points on the adaptation of a straight wire to the lingual arch form / 대한치과교정학회지

OBJECTIVE: The aim of this study is to compare the adaptation of a straight wire between brackets positioned at the mid-lingual surface and those placed gingivally by using a three-dimensional simulation software. METHODS: This cross-sectional study was performed using OrthoAid, an in-house software. The subjects were 36 adolescents with normal Class I occlusion. For each dental cast, two bracket positioning approaches, namely the middle and gingival, were examined. In the middle group, the reference points were placed on the mid-lingual surface of each tooth, while in the gingival group, the reference points were positioned lingually on the anterior teeth. A 4th degree polynomial was adopted, and the in-plane and off-plane root mean squares (RMSs) of the distances between the reference points and the fitted polynomial curve were calculated using the software. Statistical analysis was performed using the paired-samples t-test (α = 0.05). RESULTS: The mean in-plane RMS of the polynomial curve to the bracket distance in the gingival group was significantly lower than that in the middle group (p < 0.001). The off-plane RMS was higher in the gingivally positioned brackets in the maxilla than in the middle group (p < 0.001). However, the off-plane RMS in mandible was not statistically significantly different between the two groups (p = 0.274). CONCLUSIONS: The results demonstrated that the gingival placement of lingual brackets on the anterior teeth could decrease the distance between a tooth and the straight wire.

A nova ortodontia é estética e digital: você estará pronto, doutor? / The new orthodontics is aesthetics and digital: will you be ready, doctor?

Evidências recentes revelaram que os pilares que sustentam a Nova Ortodontia estão fundamentados no desejo do paciente pela estética do sorriso e na utilização de tecnologia digital na produção dos aparelhos ortodônticos. Neste contexto, a técnica lingual e os alinhadores gerados pela tecnologia CAD-CAM são propostas que reúnem exatamente estes quesitos. Neste artigo, o leitor é incitado a refletir sobre o tema e conclui que será inevitável que o ortodontista acompanhe esta tendência. Por conseguinte, esta será uma atitude decisiva para atender à crescente exigência do público de pacientes adultos, num futuro muito próximo (AU)

Recent evidences indicate that new orthodontics is based on the patients' search for smile aesthetics and on digital technology to manufacture orthodontic appliances. In this scenario, lingual technique and aligners generated by CAD/CAM system are approaches that combine exactly both mentioned aspects. The present paper incites the reader to think about this subject and concludes that orthodontists will have to follow this trend in order to meet the demands of adult patients in a very near future. (AU)

Ortodontia lingual x alinhadores removíveis: quando utilizar / Lingual orthodontics x removable aligners: when to use

A Ortodontia está passando por uma nova fase. Muitos pacientes adultos estão buscando o tratamento atualmente e não querem usar um aparelho convencional. Isso tem feito com que a Ortodontia desenvolva novos métodos de tratamento mais estéticos e também aprimore os já existentes. Duas modalidades de tratamento têm ganhado muito destaque nos últimos anos: a Ortodontia Lingual e os Alinhadores Removíveis. O objetivo deste artigo é descrever a técnica lingual Harmony e os alinhadores removíveis Essix e Clear Aligner, comparando-os e mostrando o tratamento de dois casos clínicos. Para o caso tratado com a técnica Lingual foi escolhido o aparelho Harmony devido à necessidade de grande controle de torque nos incisivos superiores. O caso tratado com alinhadores era um caso simples de recidiva pós-tratamento ortodôntico. Os casos clínicos descritos evidenciaram o papel importante que as novas modalidades de tratamento estético podem ter na Ortodontia contemporânea. Cabe ao ortodontista clínico conhecer essas ferramentas e as utilizar nos casos apropriados.(AU)

Orthodontics is going through a new phase. Many adult patients are currently seeking treatment and do not want to use a conventional device. This has led Orthodontics to develop new aesthetic treatment methods, as well as to improve existing ones. Two treatment modalities have gained much prominence in recent years: Lingual Orthodontics and Removable Aligners. The purpose of this article isx to describe the Harmony lingual technique and the Essix and Clear Aligner removable aligners, comparing them and showing the treatment of two clinical cases. For the case treated with the lingual technique, the Harmony device was chosen due to the need for great torque control in the upper incisors. The case treated with aligners was a simple case of orthodontic posttreatment relapse. The clinical cases described evidenced the important role that the new modalities of aesthetic treatment can have in contemporary Orthodontics. It is up to the clinical orthodontist to know these tools and use them in appropriate clinical cases.(AU)

Construction and assessment of a three-dimensional finite element model of mandibualr second molar mesialization using customized lingual appliance and mini-implant / 中华口腔医学杂志

Objective@#To construct a three-dimensional (3D) finite element model and analyze the biomechanical characteristics during mandibular second molar mesialization using customized lingual appliances and mini-implant.@*Methods@#One adult student volunteer from The First Affiliated Hospital of Zhengzhou University with lower left first molar extraction was selected. After CT scanning, Mimics, Geomagic, ANSYS were employed to develop a 3D finite element model including customized lingual brackets, stainless steel lingual arch wire, buccal buckles, lower dentition, periodontal ligaments and alveolar bone. Four different loading methods (1. the force of 1.470 N loaded at the lingual side only; 2, 3, 4. the forces of 0.490, 0.735 and 0.980 N loaded at both buccal and lingual sides, respectively.) were included. The initial displacements of the lower second molar and stress distribution in the periodontal ligaments were analyzed.@*Results@#More uniform stress distributions in the periodontal membrane of mandibular left second molar were found when the mesial force were loaded at both buccal and lingual sides than the force loaded at lingual side only. More inclination of the second molar was observed when force loaded at both sides than at lingual side only. With the values of the force increased, the mesial inclination potential of the second molar, the initial movement of the second molar and the stress distribution in the periodontal membrane increased. Under the force of 0.735 N at both buccal and lingual sides, mesially inclined initial displacements of the mandibuar second molar were observed and the stress values of von Mises was in the suitable area.@*Conclusions@#Less second molar rotation was found when the force loaded at both buccal and lingual sides than loaded at lingual side only. However, force loaded at both sides would increase the measial inclination potential of the second molar.

A comparison between two lingual orthodontic brackets in terms of speech performance and patients' acceptance in correcting Class II, Division 1 malocclusion: a randomized controlled trial

ABSTRACT Objective: To compare speech performance and levels of oral impairment between two types of lingual brackets. Methods: A parallel-group randomized controlled trial was carried out on patients with Class II, Division 1 malocclusion treated at the University of Hama School of Dentistry in Hama, Syria. A total of 46 participants (mean age: 22.3 ± 2.3 years) with maxillary dentoalveolar protrusion were randomly distributed into two groups with 23 patients each (1:1 allocation ratio). Either STb (Ormco) or 7th Generation (Ormco) lingual brackets were applied. Fricative sound/s/ spectrograms were analyzed directly before intervention (T0), one week following premolar extraction prior to bracket placement (T1), within 24 hours of bracket bonding (T2), one month after (T3), and three months after (T4) bracket placement. Patients′ acceptance was assessed by means of standardized questionnaires. Results: After bracket placement, significant deterioration in articulation was recorded at all assessment times in the 7th Generation group, and up to T3 in the STb group. Significant intergroup differences were detected at T2 and T3. No statistically significant differences were found between the two groups in reported tongue irritation levels, whereas chewing difficulty was significantly higher in the 7th Generation group one month after bracket placement. Conclusions: 7th Generation brackets have more interaction with sound production than STb ones. Although patients in both groups complained of some degree of oral impairment, STb appliances appeared to be more comfortable than the 7th Generation ones, particularly within the first month of treatment.

RESUMO Objetivo: comparar dois tipos de braquetes linguais, em termos de influência na fala e comprometimento da dicção. Métodos: foi realizado um estudo clínico randomizado com grupos paralelos, em pacientes portadores de má oclusão de Classe II, divisão 1, tratados na Faculdade de Odontologia da University of Hama, em Hama, na Síria. No total, 46 participantes (idade média de 22,3 ± 2,3 anos), com protrusão dentoalveolar maxilar foram aleatoriamente distribuídos em dois grupos com 23 pacientes cada (coeficiente de alocação = 1:1). Foram utilizados braquetes linguais STb (Ormco) ou braquetes linguais 7th Generation (Ormco). Foram analisados espectrogramas do som fricativo /s/ imediatamente antes da intervenção (T0), uma semana após a extração dos pré-molares previamente à colagem dos braquetes (T1), após 24 horas da colagem dos braquetes (T2), um mês depois (T3) e três meses depois (T4) da colagem dos braquetes. A aceitação dos pacientes foi avaliada por meio de questionários padronizados. Resultados: após a inserção dos braquetes, registrou-se deterioração significativa da dicção, em todos os intervalos de avaliação, no grupo com os braquetes 7th Generation; e até o intervalo T3, no grupo com braquetes STb. Foram identificadas diferenças intergrupos significativas em T2 e T3. Não foram encontradas diferenças estatisticamente significativas entre os dois grupos quanto aos níveis de irritação lingual relatados, ao passo que as dificuldades na mastigação foram significativamente maiores no grupo com braquetes 7th Generation um mês após serem inseridos. Conclusões: os braquetes 7th Generation apresentam maior interferência na dicção do que os braquetes STb. Embora os pacientes dos dois grupos tenham reclamado de um certo grau de comprometimento da dicção, os braquetes STb parecem ser mais confortáveis do que os braquetes 7th Generation, principalmente durante o primeiro mês de tratamento.

Effect of increasing the vertical intrusive force to obtain torque control in lingual orthodontics: A three‑dimensional finite element method study.

Context: Biomechanical differences between lingual and labial orthodontics (LiO and LaO). Aims: To investigate the effects of intrusive forces in lingual technique during retraction treatment mechanics. Settings and Design: Intrusive forces act differently in both techniques because of the different location of force vectors in relation to the center of resistance. Increasing the vertical intrusive force is one of the methods routinely used to prevent the uncontrolled tipping and obtain bodily tooth movement in LaO. However, its effects in lingual technique need to be investigated to derive at an optimal treatment mechanics. Subjects and Methods: Finite element method which has been successfully used to simulate tooth movement and optimize orthodontic mechanics effectively was used in this study. An accurate model of the upper central and lateral incisors with the surrounding structures was developed, and the “ANSYS” version 7.0 software was used for analysis. Results: Intrusive forces as high as 3.6N was required to obtain translation in LiO that too in an undesirable direction. Efforts to obtain torque control by increasing the intrusive force only would not be successful. Conclusion: Forces that produce a translation in LaO tends to produce uncontrolled tipping in lingual technique. To obtain adequate torque control in lingual technique, a combination of the reduction in horizontal retraction forces, increased lingual root torque application, and increase in vertical intrusive forces is desirable.

Técnica do arco ideal (Parte II) – passo a passo no tratamento de um caso clínico de má oclusão de classe II e doença periodontal com ortodontia lingual / Ideal arch technique (Part II) – step by step in the treatment of a clinical case of class II malocclusion and periodontal disease using lingual orthodontic

Frequentemente acometidos por enfermidades periodontais e cada vez mais relutantes com relação à exposição visual dos aparelhos fixos tradicionais, a Ortodontia Lingual aponta um promissor caminho no tratamento de pacientes adultos. Este trabalho descreve o modus operandi de um tratamento de uma paciente portadora de uma má oclusão de Classe II com aparelhos fixos linguais, inicialmente acometida por doença periodontal de origem não infecciosa. Foram seguidas as diretrizes da Técnica do Arco Ideal, descrita, em detalhes, na primeira parte deste trabalho. Os achados demonstraram a possibilidade de atenuar, por meio desta terapia, os efeitos deletérios de uma oclusão traumática sobre a saúde periodontal, até sua correção. Em segunda instância, os resultados apontam para uma solução ortodôntica factível, indicada para casos com discrepâncias sagitais severas, como no exemplo apresentado.

Lingual orthodontics is a promising alternative for the treatment of adult patients with periodontal diseases and reluctant to the use of traditional fixed appliances due to its visual aspect. This work presents the modus operandi of the treatment of a Class II malocclusion patient with fixed lingual appliances, which was at first suffering with a non-infectious peri-odontal disease. The guidelines of Ideal Arch Technique that were described in the first part of this work were followed. Results have demonstrated that while using this therapy it is possible to minimize deleterious effects of a traumatic malocclusion over periodontal health. In addition, the outcomes point to a feasible orthodontic solution indicated to patients with severe sagittal discrepancies, as observed on the reported case.

Ortodontia lingual e toxina botulínica: uma abordagem terapêutica combinada / Lingual orthodontics and botulinum toxin: a combined therapeutic approach

A Ortodontia Lingual e o emprego da toxina botulínica em Odontologia são duas áreas que têm apresentado descobertas muito promissoras nos últimos anos. Até o momento, praticamente não foram difundidas pesquisas que mencionem a associação de ambas no tratamento de maloclusões e no restabelecimento do equilíbrio facial. Este estudo tem o objetivo de relacionar as prováveis influências biomecânicas da introdução de bráquetes linguais em pacientes com parafuncionalidade. Em segunda instância, o autor demonstrará prováveis indicações do uso terapêutico da toxina botulínica em Ortodontia Lingual. Os achados evidenciaram que a propriedade de relaxamento muscular da toxina botulínica pode auxiliar substancialmente no controle de inclinação dos incisivos em pacientes com parafuncionalidade, além de auxiliar na composição da estética do sorriso, especialmente nos casos de hipertrofias musculares e na redução temporária e cosmética do sorriso gengival.

The Lingual Orthodontics and the use of botulinum toxin in Dentistry are two areas that have shown very promising discoveries in recent years. Until now, there were almost no researches disseminated that mention the combination of both in the treatment of malocclusions and to restore facial balance. This study aims to relate the possible biomechanical influences of the introduction of lingual brackets in patients with muscular parafunctional habits. As a second instance, the author will demonstrate probable indications of the therapeutic use of botulinum toxin in Lingual Orthodontics. The findings show that muscle relaxation property of botulinum toxin can substantially help in the incisors inclination control of patients with parafunctional habits and also help the smile aesthetics composition, especially in cases of muscle hypertrophy and temporary and cosmetic reduction of gummy smile.

A prática da nova Ortodontia Lingual – estudo de casos / The practice of new Lingual Orthodontics – case study

Os recentes avanços da Ortodontia Lingual mudaram o panorama dessa técnica e, ainda assim, poucos profissionais consideram sua viabilidade rotineira. Dentro dessas evoluções, encontram-se a redução do volume dos bráquetes, o advento dos sistemas autoligados e o uso de mini-implantes como componentes de ancoragem. Este trabalho mostra o estudo de dois casos de maloclusões com etiologias distintas tratados com aparelhos linguais, utilizando uma metodologia simplificada de montagem laboratorial. As vantagens e dificuldades do tratamento com os aparelhos linguais foram ressaltadas. Concluiu-se que a viabilidade da Técnica Lingual é irrevogável e vem apoiada na chancela do anseio crescente do público pela estética máxima durante o tratamento ortodôntico

Recent developments in Lingual Orthodontics have changed the overview of this technique, and yet, few professionals take into consideration its viability. Among these evolutions are: reduction of brackets volume, the advent of self-ligating systems and the use of miniscrews as anchoring components. This paper shows the study of two malocclusion cases with distinct etiologies, both treated with lingual appliances and using a simplified laboratory methodology. The advantages and difficulties of the treatment with the lingual appliances were emphasized. It was concluded that the viability of Lingual Technique is irrevocable and that it is supported by the approval of patients and their increasing desire for maximum aesthetics results during orthodontic treatment.

Evaluation Of Changes In The Oral Environment With Lingual Orthodontic Appliances.

Background & Objective: Lingual orthodontics is gaining more popularity in orthodontic centers. The purpose of present study is to evaluate changes in the oral cavity with lingual orthodontic appliances. Methodology: The epidemiological study was conducted among 45 patients with lingual orthodontics. Before the start of orthodontic treatment all the patients received proper oral prophylaxis. The incidence of White Spot Lesions (WSLs), plaque accumulation and gingivitis were evaluated at the interval of one, six and twelve months using WSL index developed by Gorelick et al., (1982), Silness & Löe plaque index and Löe & Silness gingival index respectively. The Student’s t test and ANOVA test were used with a significance level of 5%. Results: The frequency of WSLs increased with the procedure of lingual orthodontics from first month (3.2%) to six (6.7%) and twelve months (7.9%). A significant increase in the plaque index (PI) and gingival index (GI) was observed from month one to twelve months. Overall mean of PI and GI was 2.07±0.809 and 1.67±0.929 respectively among the patients. Conclusion: The occurrence of dental plaque and gingival inflammation was mostly noticed in lingual orthodontic cases as it is difficult to remove the plaque deposits around the brackets in the lingual side.

Displacement pattern of the anterior segment using antero-posterior lingual retractor combined with a palatal plate / 대한치과교정학회지

OBJECTIVE: To evaluate and compare the effects of two appliances on the en masse retraction of the anterior teeth anchored by temporary skeletal anchorage devices (TSADs). METHODS: The sample comprised 46 nongrowing hyperdivergent adult patients who planned to undergo upper first premolar extraction using lingual retractors. They were divided into three groups, based on the lingual appliance used: the C-lingual retractor (CLR) group (group 1, n = 16) and two antero-posterior lingual retractor (APLR) groups (n = 30, groups 2 and 3). The APLR group was divided by the posterior tube angulation; posterior tube parallel to the occlusal plane (group 2, n = 15) and distally tipped tube (group 3, n = 15). A retrospective clinical investigation of the skeletal, dental, and soft tissue relationships was performed using lateral cephalometric radiographs obtained pretreatment and post en masse retraction of the anterior teeth. RESULTS: All groups achieved significant incisor and canine retraction. The upper posterior teeth did not drift significantly during the retraction period. The APLR group had less angulation change in the anterior dentition, compared to the CLR group. By changing the tube angulation in the APLR, the intrusive force significantly increased in the distally tipped tube of group 3 patients and remarkably reduced the occlusal plane angle. CONCLUSIONS: Compared to the CLR, the APLR provides better anterior torque control and canine tipping while achieving bodily translation. Furthermore, changing the tube angulation will affect the amount of incisor intrusion, even in patients with similar palatal vault depth, without the need for additional TSADs.

Evaluation on effectiveness of individual lingual orthodontics and labial straight wire orthodontics by X-ray cephalometrics / 吉林大学学报(医学版)

Objective To compare the X-ray cephalometric results of teeth and skeleton relationship between individual lingual orthodontic and labial straight wire orthodontics,and to provide reliable theoretical foundation for selecting orthodontic system in clinic. Methods The general conditions of the patients, classification of malocclusion,severity of denture crowding and orthodontic design were used as the selection criteria. Thirty familiar adult patients with malocclusion in clinic were divided into two groups randomly:individual lingual orthodontics group (A group)and labial straight wire orthodontics group (B group),15 cases in each group.X-ray cephalometrics were taken using Steiner and Tweed cephalometrics analysis,the results of analysis were compared between pre-treatment and post-treatment in two groups respectively, and the course of treatment in two groups was compared,too.The difference of treatment effect and course of treatment between two different orthodontic systems was evaluated.Results The relationship of first molar and canine of the patients in two groups was neutral relationship,overbite and overjet of anterior teeth was shallow,the teeth arrangement was orderly and no space was left after treatment.There was no statistically significant difference (P>0.05)between two groups in each measured values detected by Steiner Analysis after orthodontic treatment;there was no statistically significant difference (P>0.05)between two groups in each measured value detected by Tweed Analysis after orthodontic treatment;and there was no statistical significance (P>0.05 )in the D-values of Steiner Analysis and Tweed Analysis between two groups before and after treatment.The duration of treatment of the patients in two groups had no significant difference (P>0.05).Conclusion Both individual lingual orthodontics and labial straight wire orthodontics could obtain well teeth arrangement and occluding relationship and achieve satisfying clinical orthodontic outcome.

Restauração estética pós-tratamento ortodôntico lingual: relato de caso / Esthetic restoration after lingual orthodontic treatment: case repor

A Ortodontia Lingual já alcançou um lugar de destaque entre as técnicas utilizadas atualmente. São muitos os pacientes que têm optado por uma opção de tratamento mais estético. Como na Ortodontia convencional, alguns problemas são muito similares aos encontra dos quando se opta pelo tratamento com a Ortodontia Invisível. Deve-se sempre estar atento aos problemas de origem periodontal e de discrepâncias de tamanho dentário. O caso apresentado mostra um tratamento ortodôntico lingual, onde após a correção da Classe II, foi necessário uma reanatomização dos dentes anteriores para alcançar uma estética maior para o sorriso da paciente.

Lingual Orthodontics has reached a place of prominence among the techniques currently used. There are many patients who have opted for a more aesthetic treatment. As in conventional Orthodontics, some problems are very similar to those found when opting for Invisible Orthodontics treatment. One should always be mindful of periodontal problems and tooth size discrepancies. This case shows a lingual orthodontic treatment, in which after correction of Class II, a reanatomization of anterior teeth was needed in order to achieve better aesthetic for the patients’ smile.

Ortodontia lingual: arco reto ou arco em forma de cogumelo? / Lingual Orthodontics: straight-wire or mushroom archwire?

A Ortodontial lingual aplica dois tipos de arco com mais frequência em sua técnica. Foi introduzido mais recentemente o arco reto lingual, depois de décadas utilizando o arco em forma de cogumelo. Alguns autores defendem o uso do arco reto por terem diversas vantagens em relação ao arco cogumelo. Porém, outros ainda persistem com o arco cogumelo como uma escolha ideal para a ortodontia lingual. Esse trabalho teve como objetivo levantar comparativamente e discutir algumas vantagens e desvantagens de ambas formas de arco. Pode-se concluir que há vantagens e desvantagens em cada tipo; o arco reto pode ser uma boa opção para o ortodontista que necessita facilitações práticas para exercer a técnica e o arco em forma de cogumelo pode ser mais confortável. O arco reto pode ser uma melhor opção quando se deseja melhor controle de torque na região anterior; o arco em forma de cogumelo pode ser uma melhor opção quando se deseja alinhamentos; e os procedimentos laboratoriais para a adoção do arco reto podem ser mais trabalhosos que o arco em forma de cogumelo.

There are two archwires commonly used for lingual orthodontics. The lingual straight-wire was recently introduced after decades using the mushroom archwire. Some authors defend the use of the straight-wire affirming it has several advantages over the mushroom archwire. However, several authors still persist with the mushroom archwire as an ideal choice for lingual orthodontics technique. This study aimed to discuss the advantages and disadvantages of both archwire types establishing a comparison between both of them. It was concluded that each one of them have its advantages and disadvantages. Straigh-wire can be a good option when a more precise control of torque in the anterior region is required. In the other hand the mushroom archwire can be more comfortable, and it can also be a better option when aiming to obtain alignments. Regarding the laboratory procedures the adoption of the straight-wire can be more laborious than the mushroom archwire.

Transient dynamic analysis and optimization of a new customized lingual self-locking appliance during occluding / 医用生物力学

Objective To study the characteristics of stress distributions on a customized lingual self-locking orthodontic appliance under transient occlusal force and optimize its structure. Methods A whole 3D model including denture, appliances and wire was established by CT scanning, reverse engineering method and CAD technology; transient nonlinear dynamic analysis on this model during occluding and its structural optimization were conducted, and the optimized lingual appliance was made based on rapid prototyping technology to verify reliability of the finite element model. Results The equivalent stress on the bracket bottom was larger than that on other parts of the bracket; the maximum equivalent stress on the bracket cover was decreased by 60.9% after installing a reinforcing rib on it, which could effectively prevent stress concentration caused by the contact between the arch wire and bracket cover. The simulation results fundamentally agreed with the loading experiment on the bracket cover. Conclusions For lingual orthodontic treatment in clinic, the relative position between interaction points of the occlusal force and brackets should be concerned so as to avoid impairing the self-locking function; through optimizing the appliance design, the elastic potential energy of arch wire can be transferred more effectively to the teeth and reduce losses of the orthodontic force.

Effects of periodontal ligament thickness on mesial movement of mandibular first molar in lingual orthodontics / 医用生物力学

Objective To study the effects of the various thickness of periodontal ligament on stress and displacement of mandibular first molar and periodontal tissues during mesial movement of tooth in lingual orthodontics. Methods Based on the reverse engineering technology, the three-dimensional assembly models of the teeth, periodontal ligament and alveolar bone with the same height of alveolar bone were constructed, and thicknesses of the periodontal ligament was 0.15, 0.2, 0.25, 0.3 and 0.35 mm, respectively. The stress and displacement of periodontal ligament, root and surface of alveolar bone were analyzed under the condition of lingual tipping, rotation and translation movements. Results For the maximum stress of periodontal ligament, root and surface of alveolar bone due to different periodontal ligament thickness, the ratio of the maximum value to the minimum value was 1.46, 2.06 and 6.72, respectively. For the maximum displacement of root and the surface of alveolar bone, the ratio of the maximum value to the minimum value was 1.65 and 1.50, respectively. Corresponding with different thickness of periodontal ligament, the location of the maximum stress of root and periodontal tissues would change at root, periodontal furcation and tooth neck. Conclusions In clinical practice, changes of tooth neck, periodontal furcation and root should be observed carefully, and the translation movement is more conducive to the health of teeth and periodontal tissues for patients with thin thickness of periodontic ligament.