Dual-cured adhesive system improves adhesive properties of dentin cavities restored with a bulk-fill resin composite

Ana Margarida Dos Santos Melo,Anne Kaline Claudino Ribeiro,Vicente De Paulo Aragão Saboia,Isauremi Vieira De Assunção,Diana Araújo Cunha,Nara Sousa Rodrigues,Boniek Castillo Dutra Borges

doi:10.20396/bjos.v21i00.8666262

Abstract

Aim: To evaluate the impact of a dual-cured adhesive system on the in situ degree of conversion (DC), bond strength (BS) and failure mode (FM) of adhesive interfaces in dentin cavities restored with a bulk-fill resin composite. Methods: 4-mm-deep dentin cavities with a 3.1 C-factor were created in 68 bovine incisors (n = 17 per group). The lightcured (Scotchbond™ Universal) or the dual-cured (Adper™ Scotchbond™ Multi-purpose Plus) adhesive system was applied to the cavities, which were then restored with a bulkfill resin composite (Filtek™ Bulk Fill). In situ DC analysis was performed by means of micro Raman spectroscopy at the top and bottom interfaces. Push-out BS was measured in a universal testing machine after 24-h or 6-month water storage. FM was determined with a stereomicroscope. Data of in situ DC and BS were analyzed by two-way analysis of variance (ANOVA) and Tukey test (p<0.05), while the FM was analyzed descriptively. Results: The groups that received the dual-cured adhesive system showed statistically higher in situ DC and BS than those that received the light-cured adhesive system. Cohesive failure mode was the most frequent in all conditions. Conclusion: In situ DC and BS were influenced by the curing strategies of the adhesive systems with better performance of the dual-cured material.

Highlights

The proper cure of the adhesive system is one of the factors needed to achieve the required mechanical properties[1] and longevity[2,3] of dental restorations
The use of dual-cured adhesive systems has been suggested in 2-mm-deep cavities resulting in greater dentin bonding durability[8], probably due to their higher degree of conversion in the hybrid layer and faster cure
Teeth were decontaminated in a water solution of thymol (0.1%) at 4oC for a week, and the roots were removed at the cementoenamel junction (CEJ) with a diamond saw using a precision cutting machine (Isomet 1000; Buehler, Lake Forest, IL, USA) under irrigation

Summary

Introduction

The proper cure of the adhesive system is one of the factors needed to achieve the required mechanical properties[1] and longevity[2,3] of dental restorations. Areas of the cavity preparation for direct resin composite restorations that are too far from the curing light tip may receive insufficient energy, negatively affecting the degree of conversion and bond stability[7] To overcome this inconvenience, the use of dual-cured adhesive systems has been suggested in 2-mm-deep cavities resulting in greater dentin bonding durability[8], probably due to their higher degree of conversion in the hybrid layer and faster cure. The use of dual-cured adhesive systems has been suggested in 2-mm-deep cavities resulting in greater dentin bonding durability[8], probably due to their higher degree of conversion in the hybrid layer and faster cure When such tooth preparations occur in posterior teeth, the tip of the curing light can be set even further than 2 mm in certain dentin sites, negatively affecting interfacial properties in such areas. The null hypothesis tested was that different curing strategies of adhesive systems and storage times would not affect the physical properties of the adhesive interface

Materials and Methods

Findings

Results