The effect of temperature variation of composite orthodontic adhesive on shear bond strength (In vitro comparative study)

Abstract

Background: The temperature of the adhesive may influence the chemical reactions and consequently interfere with bonding procedures, compromising the quality and durability of the bonding. This in vitro study was designed to assess and compare the effect of temperature variation in an orthodontic office on the shear bond strengths and the types of bond failure of two composite adhesive systems, a No-Mix and Light Cure adhesive systems. Materials and Methods: Ninety sound human upper first premolars were collected and divided randomly into six equal groups, three groups for One-Step and three groups for Light Cure adhesive systems with 15 teeth each. After a careful and standardized bonding procedure, the samples were subjected to shear tests using a Tinius-Olsen Universal Testing machine. After debonding, the bracket bases and the corresponding teeth were examined under a stereomicroscope with a magnification of 20X to determine the predominant failure type. Results: The results of this study showed that for the One-Step system temperature variation has a non-significant difference, while for the Light Cure system the refrigerated adhesive has significant higher shear bond strength. There was a non-significant difference in the failure site for both of the adhesive systems used in the study. Conclusion: In short, temperature variation affected Light Cure adhesive system more than No-Mix adhesive system.