Comparação da resistência ao cisalhamento após colagem com dois cimentos ortodônticos ­ estudo in vitro / A comparison of shear bond strength after bonding with two orthodontic cements ­ an in vitro study

O objetivo deste trabalho foi avaliar a resistência ao cisalhamento de bandas ortodônticas cimentadas com um novo compósito Orthobite, comparando-as ao cimento ionômero de vidro convencional em esmalte bovino e analisar o Índice de Remanescente Adesivo (IRA). A amostra consistiu de 30 dentes bovinos divididos em 2 grupos: Grupo I ­ Orthobite (FGM) e Grupo II ­ CIV MERON (VOCO). Foi realizada profilaxia com pedra-pomes e água, seguida da cimentação conforme instruções dos fabricantes. Logo após, os mesmos foram submetidos ao ensaio de cisalhamento com velocidade de 0,5 mm/minutos. Os dados foram submetidos aos testes de T Student e Kruskal-Wallis. Foram encontradas diferenças estatísticas significantes entre os grupos, tanto nos valores de resistência ao cisalhamento (p>0,05), quanto na avaliação do IRA (p>0,05). O cimento Orthobite mostrou-se estatisticamente superior ao MERON, ou seja, apresentou um melhor vedamento das margens e uma maior resistência ao deslocamento, dessa forma essa união estável entre o dente e a banda é fundamental para o sucesso do tratamento ortodôntico (AU)

The objective of this study was to evaluate the shear strength of orthodontic bands cemented with a new Orthobite composite, comparing them to the conventional glass ionomer cement in bovine enamel and to analyze the Adhesive Remnant Index (ARI). The sample consisted of 30 bovine teeth divided into 2 groups: Group I ­ Orthobite (FGM) and Group II ­ CIV MERON (VOCO). Prophylaxis has been made with pumice and water followed by cementation according to the manufacturer's instructions. Afterwards, they were subjected to the shear test at a speed of 0.5 mm/minute speed. Data were submitted to the Student T and Kruskal-Wallis tests. Significant statistical differences were found between the groups both in the shear strength values (p> 0.05) and in the ARI assessment (p> 0.05). The Orthobite cement proved to be statistically superior to MERON, that is, it presented a better margins seal and a greater resistance to displacement, so this stable union between the tooth and the band is fundamental for the success of the orthodontic treatment. (AU)

Evaluation of the Shear Strength of Orthodontic Bands Cemented with New Composite Using Adhesive System / Evaluación de la Resistencia al Cizallamiento de Bandas Ortodónticas Cementadas con Nuevo Compuesto Utilizando Sistema Adhesivo

ABSTRACT: Orthodontic cements have been used to enhance retention between the band and the crown, however, unfavorable properties found in many of these cements may contribute to cement failure between band and crown's surface and leading to unsuccessful application of orthodontic forces. The aim of this study was to evaluate the shear strength of the Orthobite composite (FGM) using the Single Bond adhesive system (3M). The sample consisted of 30 bovine incisors divided in 2 groups (n=15). All teeth were submitted to prophylaxes with pumice stone and etching with phosphoric acid. In Group I the Orthobite was used conventionally. Group II was similar to Group I, however, the Single Bond adhesive system was applied after conditioning. The samples were stored in distilled water in incubator at 37 ºC for 24 h and submitted to the shear strength test at a speed of 0.5 mm/minute speed. Data were submitted to the Student T test (5 %). The results (MPa) showed no statistically significant differences between the groups, regardless of surface treatment. Thus, all groups exhibited adequate adhesive bond strength for clinical use.

RESUMEN: Los cementos ortodónticos se han utilizado para aumentar la retención entre la banda y la corona, sin embargo, las propiedades desfavorables encontradas en muchos de estos cementos pueden contribuir a la falla del cemento entre la superficie de la banda y la corona y llevar a la aplicación incorrecta de fuerzas de ortodoncia. El objetivo de este trabajo fue evaluar la resistencia al cizallamiento del compuesto Orthobite (FGM) utilizando el sistema adhesivo Single Bond (3M). La muestra consistió de 30 incisivos bovinos divididos en dos grupos (n = 15). Todos los dientes recibieron profilaxis con piedra pómez y acondicionamiento del esmalte con ácido fosfórico. En el Grupo I, se utilizó Orthobite de manera convencional. El Grupo II fue similar al I, pero se aplicó el sistema adhesivo Single Bond, después de acondicionamiento. Los cuerpos de prueba fueron almacenados en agua destilada en estufa a 37 ºC por 24 h y sometidos al ensayo de resistencia al cizallamiento, con velocidad de 0,5 mm por minuto. Los datos fueron sometidos a la prueba de T Student (5 %). Los resultados (en MPa) no mostraron diferencias estadísticamente significativas entre los grupos, independientemente del tratamiento de la superficie. De esta forma, todos los grupos presentaron resistencia adhesiva adecuada para uso clínico.

Ceramic Laminate Veneers for Reestablishment of Esthetics in Case of Lateral Incisor Agenesis.

The increasing demand of patients looking for esthetics has resulted in the development of several techniques to restore anterior teeth. Conservative treatments should always be the first therapeutic option for the solution of aesthetic problems involving morphological changes and usually provide the result that the patient expects. In this context, ceramic laminate veneers, also known as "contact lenses," are capable to provide an extremely faithful reproduction of natural teeth with great color stability and periodontal biocompatibility. Minimal or no preparation veneers are heavily advertised as the answer to patients' cosmetic needs, when properly indicated by the dentist. This paper reports a clinical case where lateral incisor agenesis was aesthetically corrected using ceramic laminates.