Uma análise dos testes in vitro de força de adesão em Ortodontia

Abstract

The aim of this study was to examine the recent methodology used in laboratory analysis of bond strength in orthodontics. The material used was all the articles published in the American Journal of Orthodontics and Dentofacial Orthopaedics or The Angle Orthodontics in which the bonding between the bracket and several surfaces were evaluated by Instron Universal Testing Machine or similar devices. It was found 127 articles, in which 86% tested the specimens in shear mode, and 14% used the tensile technique. Among the studies with human teeth (68%) premolars were the most frequent (57%), followed by molars (31%). According to the number of specimens per group, 28 studies analysed from 6 to 10; 30 from 11 to 15; 33 from 16 to 20; and 36 analyzed more than 20 specimens. According to nature of the storage solution, the most used were distilled water (43%), followed by 0.1% Timol (28%) and 0.9% saline solution (12%). With regard to the cross head speed, in 25 studies were of 0,5mm/min; in 43 were of 1.0mm/min; in 8 was of 2.0mm/min; and in 38 was of 5.0mm/min. The authors concluded that there was not an agreement in the methodology on those studies, and so there is a potential need of technique standardization.

The influence of adhesives and the base structure of metal brackets on shear bond strength

“…The parameters that influence the tests are dental material, type of adhesive, bracket base structure, specimen storage, and the testing machine's shearing velocity. This large number of parameters made it difficult to compare our values with those obtained in earlier investigations [7,13,14].…”

“…Die Prüfparameter, welche die Tests beeinflussen, sind: Zahnmaterial, Art des Adhäsivs, Struktur der Bracketbasis, Lagerung der Prüfkörper und die Abschergeschwindigkeit der Prüfmaschine. Diese Vielzahl der Parameter erschwerte den Vergleich der erzielten Werte in früheren Arbeiten untereinander [7,13,14]. ing of a bracket during orthodontic treatment is an annoying complication.…”