Temperature change of the pulpal floor and restoration with preheated bis-GMA free and containing resin composite (a randomized clinical trial)

Abstract

Abstract Background Preheating is one of several innovative approaches and improvements developed to increase the durability and clinical behavior of resin composites. Development of preheated composites is to reduce its viscosity in order to improve resin composite adaptation and placement ease. The purpose of this clinical trial was to study the effect of preheating Bis-GMA free and Bis-GMA-containing resin composites at different temperatures on the pulpal floor and restoration temperature. A total of twenty individuals (N = 40) have two carious posterior teeth that need to be restored were randomly assigned to one of two groups based on the type of restorative materials used: (group 1) Bis-GMA-containing resin composite VisCalor bulk (VCB), and (group 2) Bis-GMA-free resin composite Admira Fusion x-tra (AFX). Preheating temperatures of 50 °C and 70 °C were utilized to separate each group into two subgroups. Class I or II cavities were prepared. Thermometer device with two separate K-type temperature probes was used to measure the base line temperature values at the pulpal floor before beginning the restorative procedure (C0), pulpal floor during packing of preheated composite (C1), the top composite surface after packing and before curing (C2), pulpal floor after curing of the preheated composite (C3), and top composite surface after curing (C4). One-way ANOVA and the Kruskal–Wallis test were used to analyze the data. Results The measured temperature of pulpal floor for both preheated VCB or AFX at 50 °C or 70 °C revealed significant increasing from base line measured temperature to during packing as well as after curing with (P-value < 0.001). There was no significant difference for mean composite surface temperature for both preheated materials at 50 °C or 70 °C whether before or after curing. Conclusions Preheating of bulk fill Bis-GMA free and containing resin composite rises both the pulpal floor and the restoration temperature; meanwhile, the rise in temperature was limited. The application of the curing unit caused the greatest temperature rise.