EFFECT OF COMPOSITE PREHEATING AND PLACEMENT TECHNIQUES ON MARGINAL INTEGRITY OF CLASS V RESTORATIONS

Abstract

Introduction: Different placement techniques of resin-based composite (RBC) systems have been developed to improve the marginal adaptation and reduce microleakage. These techniques included preheating and vibration of resin composite materials. Objectives: The current study aimed to investigate the effect of preheating and placement techniques on microleakage and marginal gap formation of class V composite restorations. Materials and methods: A total of eighty sound extracted human molars were used in this study. Standard class V cavities were prepared on their buccal surfaces (4mm mesiodistally, 3mm occlusocervically, and 3 mm pulpal depth). The teeth were divided into 4 groups (n=20): Group I: restored with Filtek bulk fill flowable composite, Group II: restored with Filtek bulk fill composite after it was heated to 60°C using Calset device, Group III: restored with Filtek bulk fill composite adapted with a vibrating instrument (Compothixo), Group IV: restored with Filtek Z350 XT. Specimens were light cured, thermocycled between (5 oC and 55 oC in water) and marginal gaps assessment was measured under a stereomicroscope and measured in micrometers. Then teeth were dyed with 0.5% basic fuchsin dye for 24 hours. The dyed specimens were sectioned in the buccolingual direction and evaluated for microleakage (dye penetration) using a stereomicroscope. Results:For marginal gap assessment, results revealed a significant difference between the tested groups, where flowable bulk‑fill showed the lowest statistically significant marginal gaps compared to other groups at the occlusal and gingival margins (p < 0.05). For the microleakage test, the groups showed more microleakage at gingival margins compared to occlusal margins, flowable bulk- fill and preheated bulk -fill showed the lower microleakage scores among groups. Conclusions: None of the placement techniques produced gap-free margins. Flowable bulk-fill composite and preheated composite preserved better marginal integrity and reduced microleakage.