A comparative evaluation of preheat treatment, postcure heat treatment, and combined heat treatment on degree of conversion of a bulk-fill composite: An in vitro study.

Abstract

The aim of this study was to evaluate the effect on the degree of conversion of Tetric N-Ceram Bulk Fill Composite subjected to preheat treatment, postcure heat treatment, and combined heat treatment. A total of 90 samples were prepared from Tetric N-Ceram Bulk Fill using customized stainless steel molds and divided into six groups of 15 samples each based on the heat treatment. Group I (control group): no heat treatment, Group II: preheat treatment at 60°C, Group III: postcure heat treatment at 100°C, Group IV: postcure heat treatment at 200°C, Group V: combined preheat treatment at 60°C and postcure heat treatment at 100°C, and Group VI: combined preheat treatment at 60°C and postcure heat treatment at 200°C. The degree of conversion was analyzed using Raman spectrometer. Data were analyzed using analysis of variance followed by the Scheffé test using Statistical Package for the Social Sciences 20.0 version. The order of values of degree of conversion from maximum to minimum for the groups are as follows: Group VI (98.77 ± 0.52) > Group V (97.11 ± 0.78) > Group IV (95.00 ± 0.86) > Group III (93.00 ± 1.22) > Group II (86.88 ± 1.36) > Group I (76.55 ± 1.42). The statistical analysis revealed a statistically significant difference between the groups (P < 0.05). Combined heat treatment samples showed better values of degree of conversion.