Stability of open bite treatment with occlusal adjustment

O objetivo desse trabalho foi avaliar cefalométrica e clinicamente a estabilidade em longo prazo do tratamento da mordida aberta anterior por meio do ajuste oclusal, bem como a sensibilidade dentinária causada por esse procedimento em longo prazo. A amostra consistiu de 17 pacientes dentre mais de 4000 pacientes tratados nos cursos de Pós-Graduação (Latu e Strictu sensu) da Disciplina de Ortodontia da Faculdade de Odontologia de Bauru - USP, com mordida aberta anterior e que haviam sido previamente tratados ortodonticamente e apresentaram recidiva do trespasse vertical negativo (em média de -1,06mm) e foram retratados com a técnica do ajuste oclusal. As alterações cefalométricas foram avaliadas em telerradiografias em norma lateral, obtidas de cada um dos pacientes antes e logo após a realização do procedimento de ajuste oclusal, e em longo prazo (média de 3,4 anos após o ajuste). Concomitantemente, foi realizada uma avaliação da sensibilidade dentinária em longo prazo (3,4 anos pós-ajuste), que foi comparada com a sensibilidade encontrada nos pacientes antes, 1,35 e 4,61 meses após a realização do ajuste oclusal. Os resultados demonstraram que algumas das alterações conseguidas com a realização do ajuste oclusal, como a diminuição da altura facial ântero-inferior (AFAI) e da altura posterior molar (APM) e o aumento do trespasse vertical apresentaram uma recidiva significante em longo prazo. Apesar disso, a maioria das alterações obtidas com o tratamento permaneceu estável em longo prazo. Os pacientes com menos de 21 anos apresentaram o mesmo comportamento em longo prazo que a amostra total. Porém, os pacientes com 21 anos ou mais apresentaram estabilidade do trespasse vertical, apesar de apresentarem também uma recidiva da AFAI e da APM em longo prazo. Houve correlação da recidiva da mordida aberta anterior com a recidiva da AFAI e com a retrusão do lábio inferior em longo prazo. Houve diferença significante da sensibilidade à mastigação, calor, frio e percussão entre as fases antes e 1,35 meses após o ajuste, porém 4,61 meses depois, a sensibilidade já havia retornado aos níveis normais prévios ao desgaste, e isto se manteve em longo prazo. Apesar da recidiva estatisticamente significante da mordida aberta anterior observada, houve estabilidade \"clinicamente significante\" em 66,7% dos casos .The objective of this study was to evaluate the cephalometric and clinical longterm stability of anterior open bite treatment with occlusal adjustment, as well as the dentinal sensitivity caused by this procedure in the long-term. The sample consisted of 17 patients among more than 4,000 treated in Graduating Program (Latu and Strictu sensu) of the Orthodontics Discipline at Bauru Dental School - USP, with open bite and who were previously treated and that presented a relapse of the negative vertical overbite (mean of -1.06mm) and were retreated with occlusal adjustment technique. The cephalometric changes were evaluated in lateral headfilms obtained from each patient before and after the occlusal adjustment procedure, and in the long-term (mean of 3,4 years after occlusal adjustment). Concurrently, dentinal sensitivity was also evaluated before, after 1.35 and 4.61 months of the occlusal adjustment and in the long-term (3,4 years after adjustment). Results demonstrated that some of the alterations obtained with the occlusal adjustment, such as the decrease of lower anterior face height (LAFH) and posterior molar height (PMH) and the increase of the overbite, presented a significant relapse in the long-term. However, most of the changes obtained with treatment remained stable in the long-term. Patients younger than 21 years-old showed the same long-term behaviour than the whole sample. Therefore, patients aging 21 years or older presented stability of the overbite, despite they also presented a relapse of LAFH and PMH in the long-term. There was correlation of open bite relapse with the LAFH relapse and with the retrusion of the lower lip in the long-term. There was significant difference of dentinal sensitivity to mastication, heat, cold and percussion among the stages before and 1,35 months after occlusal adjustment, but 4,61 months after, sensitivity returned to normal levels exhibited previous to adjustment, and this remained stable in the long-term. In spite of the statistically significant relapse of anterior open bite

Estudo da recidiva da sobremordida relacionada com a curva de Spee, em pacientes Classe II, divisão 1, na fase pós-contenção

INTRODUÇÃO: a estabilidade dos resultados do tratamento ortodôntico é um assunto muito estudado na literatura, sem respostas conclusivas. A sobremordida, ou trespasse vertical, define-se como a relação vertical entre as bordas incisais dos incisivos superiores e inferiores, apresentando-se como um aspecto importante na avaliação dos resultados do tratamento e sua estabilidade. OBJETIVO: este estudo se propôs a avaliar a recidiva da sobremordida e sua relação com a curva de Spee. METODOLOGIA: a amostra (grupo experimental) constituiu-se de 29 pacientes, de ambos os gêneros, apresentando má oclusão de Classe II, divisão 1, e sobremordida mínima de 3,5mm, tratados com extração dos 4 primeiros pré-molares. Este grupo foi comparado a um grupo controle, com oclusão normal. A amostra faz parte do Arquivo da Disciplina de Ortodontia da FOB-USP. Avaliaram-se as telerradiografias em norma lateral e os modelos de estudo do início, final e 5 anos pós-tratamento e, para o grupo controle, as telerradiografias de dois tempos de avaliação, compatível com o tempo de tratamento do grupo experimental. Para comparação intergrupos, utilizou-se o teste t independente e, para comparação intragrupo, os testes ANOVA e Tukey. Para verificar a relação da recidiva da sobremordida com a curva de Spee, utilizou-se o coeficiente de correlação de Pearson. RESULTADOS: pela análise dos resultados obtidos, observou-se que a sobremordida apresentou uma correção significante durante o tratamento, comparando-se ao grupo controle. Porém, apresentou recidiva significante na fase pós-contenção. CONCLUSÃO: a recidiva da sobremordida apresentou uma correlação significante com a curva de Spee na fase pós-contenção.INTRODUCTION: the long-term stability of the treatment outcomes presents as one of the main points in orthodontic literature, without conclusive answers. The overbite is defined as the vertical distance between upper and lower incisors, and it is important for evaluation of treatment and its stability. AIM: this study aimed to evaluate, in cephalograms and study casts, the overbite relapse and its relation with the curve of Spee. METHODS: the sample (experimental group) comprised 29 patients of both genders, presenting Class II, division 1 malocclusion and an overbite of at least 3.5mm, treated by Edgewise mechanics. This experimental group was compared to a control group of normal occlusion, comprising 29 subjects. Both groups are part of the records from Orthodontics Department at Bauru Dental School, University of São Paulo. For the experimental group, cephalograms and study casts of the pretreatment, posttreatment and 5 years post retention were studied, and for the control group, cephalograms in two times of evaluation, compatible with the treatment time of the experimental group. The independent t test was used for the intergroup comparison, and the one way ANOVA and Tukey test, for intragroup comparison. In order to verify the relation between the overbite relapse and the curve of Spee, a Pearson s correlation test was performed. RESULTS: the results showed that the overbite was significantly corrected by the orthodontic treatment, when compared to control group, and presented a significant relapse in the post retention stage. CONCLUSION: the overbite relapse presented significant correlation with the curve of Spee in the post retention stage

Stability of anterior open-bite treatment with occlusal adjustment

Introduction: In this study, we aimed to evaluate the long-term stability of anterior open-bite treatment with occlusal adjustment and the dentinal sensitivity caused by this procedure in the long term. Methods: The sample comprised 17 open-bite patients who experienced relapse of the negative vertical overbite after orthodontic treatment and were retreated with occlusal adjustment. The cephalometric changes were evaluated on lateral cephalograms obtained before and after the occlusal adjustment and in the long term (mean, 3.4 years after occlusal adjustment). Dentinal sensitivity was also evaluated before the occlusal adjustment, and 1.35 months, 4.61 months, and 3.4 years later. The cephalometric statuses between the 3 evaluations were compared with analysis of variance (ANOVA) and Tukey tests. The percentages of clinically significant relapse were calculated. To compare dentinal sensitivity at the several stages, nonparametric Friedman and Wilcoxon tests were performed. Results: Statistically significant relapse of anterior open bite occurred in 33.3% of the patients. Those who had the procedure before 21 years of age were most likely to experience relapse. Dentinal sensitivity remained within the normal range in the long term. Conclusions: Despite the statistically significant relapse of anterior open bite, clinically significant stability was found in 66.7% of the patients. (Am J Orthod Dentofacial Orthop 2010; 138:14.e1-14.e7

Evaluation of anterior open-bite treatment with occlusal adjustment

Introduction: The purpose of this study was to evaluate the cephalometric and occlusal changes, the functional occlusion, and the dentinal sensitivity of anterior open-bite treatment with occlusal adjustment. Methods: The sample comprised 20 patients who experienced relapse of the anterior open bite (mean, -1.06 mm). Occlusal adjustment was performed until a positive overbite was established. Cephalometric changes were evaluated on lateral cephalograms taken before and after the occlusal adjustment. The functional occlusion analysis consisted of evaluating immediate anterior and canine guidance and the number of teeth in contact before and after the procedure. Dentinal sensitivity was evaluated before, shortly after, and 4.61 months after the occlusal adjustment. Pretreatment and posttreatment cephalometric changes and the number of teeth in contact were compared with dependent t tests. Percentages of anterior and canine guidance before and after the adjustment procedure were compared with the McNemar test. To compare dentinal sensitivity at several stages, the nonparametric Friedman test was used, followed by the Wilcoxon test. Results: Significant increases in overbite and mandibular protrusion were seen, as were significant decreases in apical base discrepancy, facial convexity, and growth pattern angles. The percentages of immediate anterior and canine guidance increased significantly, as did the number of teeth with occlusal contacts. Dentinal sensitivity increased immediately after the adjustment but decreased to normal levels after 4.61 months. Conclusions: Occlusal adjustment is a viable treatment alternative for some open-bite patients; it establishes positive vertical overbite and improves the functional occlusion with only transient dentinal sensitivity

Effect of hydrofluoric acid concentration and thermal cycling on the bond strength of brackets to ceramic

This study to evaluate the effects of different hydrofluoric acid (HF) concentrations and thermal cycling on the shear bond strength (SBS) of brackets to ceramic. Cylinders of ceramic were divided into 10 groups (n=15), according to HF concentrations: 1-1%;2- 2.5%;3-5%;4-7.5%;5-10% (storage 24 h); 6-1%;7-2.5%;8-5%;9-7.5%; and, 10-10% (thermal cycling). All cylinders were etched for 60s and received one layer of silane. Metallic brackets were bonded to the cylinders using Transbond-XT, light activated for 40 s, using a LED (Radii Plus) and stored in deionized water at 37o C for 24h. The groups 6 to 10 were submitted to thermal cycling (7,000 cycles – 5o/55oC). SBS was performed in an Instron at crosshead speed of 1.0 mm/min. Data were submitted to two-way ANOVA and Tukey’s post-hoc test (α=0.05). The Adhesive Remaining Index (ARI) was evaluated at 40x magnification. The different HF acid concentrations influenced on the SBS of the brackets to ceramic306587591CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ304493/2014-

Influence of Thermal Cycles Number on Bond Strength of Metallic Brackets to Ceramic

<div><p>Abstract The aim of this study was to evaluate the effect of different number of thermal cycles on the shear bond strength (SBS) of metallic orthodontic brackets bonded to feldspathic ceramic by a composite resin. Twenty-five ceramic cylinders were etched with 10% hydrofluoric acid for 60 s and received two layers of silane. Brackets were bonded to the cylinders using Transbond XT and assigned to 5 groups (n=5): Group 1 - Control group (without thermal cycling); Group 2 - 500 thermal cycles; Group 3 - 5,000 thermal cycles; Group 4 - 7,000 thermal cycles and Group 5 - 10,000 thermal cycles. Light-activation was carried out by Radii Plus LED. SBS testing was carried out after 24 h of storage in deionized water and thermal cycling (5/55 oC and 30 s dwell time). Five brackets were bonded to each cylinder, totalizing 25 brackets for each group. Data were submitted to one-way ANOVA and Tukey’s test (α=0.05). The Adhesive Remnant Index (ARI) was evaluated at 8× magnification. The SBS (MPa) of control group (9.3±0.8), 500 (9.0±0.7) and 5,000 (8.4±0.9) thermal cycles were significantly higher than those after 7,000 (6.8±0.6) and 10,000 (4.9±1.0) thermal cycles (p<0.05). The ARI showed a predominance of Scores 0 (adhesive failure) prevailed in all groups, as shown by the ARI, with increased scores 1 and 2 (mixed failures) for control group and 500 thermal cycles. In conclusion, thermal fatigue may compromise the bonding integration between metallic brackets and ceramic restorations. For in vitro testing, use of at least 7,000 cycles is advised to result in significant fatigue on the bonding interface.</p></div