The Effects of Thermo-mechanical Aging on Microleakage in Composite Restorations Polymerized Using One New Generation and Two Conventional Led Light Curing Units

Abstract

Objective: This study aimed to evaluate the effects of thermomechanical aging (TMA) on the microleakage scores of Class V composite restorations polymerized using one new generational and two conventional light emitting diodes (LED) light curing units (LCU). Methods: Class V cavities were prepared and restored on the buccal and lingual surfaces of 60 extracted human premolar teeth using a dental phantom head to simulate clinical conditions. After application of the adhesive system (Optibond Solo Plus, Kerr, USA) using total etch procedures. the cavities were restored with composite resin (Herculite XRV. Kerr, USA) using one new generational (Demi Ultracapacitor, Kerr, USA) and two conventional (Valo Cordless, USA and BA Optima International, UK) LED light devices. The restored teeth were then subdivided into the test (underwent TMA) and control (did not undergo TMA) groups, and the specimens were stained with 0.5% basic fuchsin dye and sectioned. Dye penetration was scored using a stereomicroscope at 40x magnification. Differences between groups were compared using the Kruskal-Wallis, Mann-Whitney U, and Wilcoxon Signed Ranks tests (p<0.05). Results: Comparison of the test and control groups by the LCUs used for polymerization showed a statistically significant difference in microleakage scores between the two (p<0.05). However, no differences in scores were observed between the new generational and two conventional LED LCUs (p>0.05). Conclusion: Thermal and mechanical aging procedures increased microlcakage in Class V composite estorations, regardless of the light curing unit used.