Depth of Cure and Mechanical Properties of Bulk-Fill Posterior Dental Composites

Saamah An,Said As,Yahya Na

doi:10.22452/adum.vol23no1.2

Abstract

The objectives of this study were to compare the microhardness, flexural strength and compressive strength of a new bulk-fill composite (SonicFillâ„¢) to a conventional nanohybrid composite (Herculite Precis) and an established bulk-fill composite (Tetric N Ceram). In addition, the depth of cure of the two bulk-fill resin composites was also investigated. The materials were prepared and tested for the mechanical properties following ISO 4049:2009. Microhardness and depth of cure were measured using Vickers hardness tester. Compressive and flexural strength were tested using a universal testing machine. To determine the depth of cure, microhardness of the bulk-fill composites were measured as a function of selected depth of materials at 0.5 mm, 2.0 mm and 4.0 mm. Data were analyzed by either one-way ANOVA or Friedman test. Analysis demonstrated that SonicFillâ„¢ gave the highest microhardness value (101.8 + 4.6 VHN) compared to the other two groups. There were no significant differences among all groups in flexural and compressive strength. The depth of cure decreased as the thickness of both bulk-fill composites increased. In conclusion, SonicFillâ„¢ showed favorable mechanical properties compared to other composites tested. In both bulk-filled groups, microhardness value decreased as the thickness of the composite increased. The polymerization of the bulk-filled composites was effective only at 2 mm or less.

Highlights

Since the introduction of dental composites into the dental market more than 40 years ago, many efforts and studies have been made to improve their clinical behavior [1,2,3,4,5]
To determine the depth of cure, microhardness of the bulk-fill composites were measured as a function of selected depth of materials at 0.5 mm, 2.0 mm and 4.0 mm
Analysis demonstrated that SonicFillTM gave the highest microhardness value (101.8 + 4.6 Vickers hardness number (VHN)) compared to the other two groups

Summary

INTRODUCTION

Since the introduction of dental composites into the dental market more than 40 years ago, many efforts and studies have been made to improve their clinical behavior [1,2,3,4,5]. Incremental layering technique has been accepted as a standard protocol for placement of dental composites to ensure adequate light curing and reduce polymerization shrinkage [2]. Several manufacturers have introduced innovative bulk-fill dental composites that can be applied to the cavity in a single increment or in thickness up to 5 mm with enhanced curing and controlled shrinkage [4]. The latter is achieved by means of novel resins, special modulators, unique fillers and filler control [6,7,8]. When the sonic energy ceases, the resin returns to its high viscosity state, facilitating sculpting and carving to the desired anatomical form Studies on this innovative bulk-fill composite system are limited. There is no difference in depth of cure between the two bulk-fill composites

MATERIALS AND METHODS

RESULTS

DISCUSSION

Findings

CONCLUSION