ABSTRACT
Aim: To evaluate the fracture strength of ceramic brackets submitted to archwire torsional strain. Methods: Different types of maxillary central incisor ceramic brackets from four different commercial brands, Roth prescription (0.022" x 0.028"), were evaluated, namely: Mystique (GAC), InVu (TP Orthodontics), Clarity (3M Unitek) and Luxi II (RMO Ortohodontics). To evaluate the fracture strength, 0.019"x 0.025" stainless steel orthodontic wires were inserted into the bracket channels and submitted to torsion until they fractured. Results: The InVu brackets showed a significantly higher fracture strength than the other brackets (p<0.05), which did not differ significantly among them (p>0.05). Conclusions: Among the brackets tested, the traditional ceramic bracket InVu showed the highest fracture strength, while the Luxi II bracket, obtained the lowest value.
Subject(s)
Orthodontics , Biomechanical Phenomena , Braces , CeramicsABSTRACT
A análise do perfil facial torna-se cada vez mais importante no diagnóstico e plano de tratamento, onde o ângulo nasolabial apresenta-se como importante estrutura da estética facial; por isso detém as maiores discussões sobre as suas formas, variações e modificações. Propõe-se neste trabalho o estudo comparativo das medidas iniciais e finais do ângulo nasolabial e da inclinação dos incisivos superiores em duas amostras tratadas com extração de primeiros pré-molares e segundos pré-molares, com Classe I de Angle, brasileiros, de ambos os gêneros, tratados ortodonticamente. A amostra foi obtida no arquivo de documentação de casos clínicos do Departamento de Ortodontia da Universidade Estadual de Minas Gerais - Campus de Lavras, com idade variando entre 11 anos e três meses e 13 anos e oito meses. Comprovou-se um aumento médio no ângulo nasolabial (ANL) de 4,68O, e uma diminuição da inclinação dos incisivos superiores (I .NA) de 6,35 graus e uma variância padronizada para o ângulo nasolabial de 4,12" e de 2,77O para os incisivos superiores. Concluiu-se que para os indivíduos tratados com extração dos quatro primeiros pré-molares houve um aumento médio do ângulo nasolabial de 10,8" e um aumento médio de 6,22O para os indivíduos tratados com extração dos segundos pré-molares. Com reação a inclinação dos incisivos superiores houve uma diminuição média de 11,95" para os indivíduos tratados com extração dos primeiros pré-molares e uma diminuição média de 5,6O para os indivíduos tratados com extração dos segundos pré-molares.
The analysis of the face profile is becoming more important for the diagnosis and for treatment plan; once the noselip angle is important for the aesthetic face structure, therefore there are increasing discussions about forms. variations and modifications. This work aims a comparative study of the initial and final measures of the noselip angle and of the inclination of the superior incisors in 2 (two) samples studied by the extraction of the first premolars and second premolars from 20 individuals, from class I of Angle, Brazilians, from both genders, who were being treated orthodontically. The samples were taken from the Archieve of Clinic Reports from the Orthodontics Department of the Universidade Estadual de Minas Gerais - Lavras Campus, while the ages varied from 11 years old to 3 months and 13 years old to 8 months. It was proved that the average increase of the noselip angle (ANL) was 4.68º, and a decrease of the inclination of the superior incisors (I.NA) was 6.35 It was also noticed a standard variation of the noselip angle of 4.12º and 2.77º on the superior incisors. In conclusion, the individuals who were treated with the extraction of the first four premolars, there was an average increase of the noselip angle of 10.8º an average increase of 6.22º on the individuals who had the extraction of the second premolars. Concerning the superior incisors inclination, there was an average decrease of 11.95 on the individuals who had the extraction of the first premolars and an average decrease of 5.6º on the individuals who had extraction of the second premolars.