Assessment of Microleakage of Class V Composite Resin Restoration Following Erbium-Doped Yttrium Aluminum Garnet (Er:YAG) Laser Conditioning and Acid Etching with Two Different Bonding Systems

Abstract INTRODUCTION: The use of laser for cavity preparation or conditioning of dentin and enamel surfaces as an alternative for dental tissue acid-etch have increased in recent years. The aim of this in vitro study was to compare microleakage at enamel-composite and dentincomposite interfaces following Erbium-Doped Yttrium Aluminum Garnet(Er:YAG) laser conditioning or acid-etching of enamel and dentin, hybridized with different bonding systems.METHODS: Class V cavities were prepared on the lingual and buccal surfaces of ۵۰ recently extracted intact human posterior teeth with occlusal margin in the enamel and gingival margin in the dentin. The cavities were randomly assigned to five groups: group۱:conditioned with laser (Energy=۱۲۰mJ, Frequency=۱۰Hz, Pulse duration=۱۰۰μs for Enamel and Energy=۸۰mJ, Frequency=۱۰Hz, Pulse duration=۱۰۰μs for Dentin) + Optibond FL, group۲:conditioned with laser + etching with ۳۵% phosphoric acid + Optibond FL, group۳:conditioned with laser + Clearfil SE Bond, group ۴ (control):acid etched with ۳۵% phosphoric acid + Optibond FL, group ۵ (control): Clearfil SE Bond. All cavities were restored using Point ۴ composite resin. All samples were stored in distilled water at ۳۷°c for ۲۴ h, then were thermocycled for ۵۰۰ cycles and immersed in ۵۰% silver nitrate solution for ۲۴ h. The teeth were sectioned bucco-lingually to evaluate the dye penetration. Kruskal-Wallis & Mann-Whitney tests were used for statistical analysis.RESULTS: In occlusal margins, the least microleakage showed in groups ۲, ۴ and ۵. The maximum microleakage was observed in group ۳ (P=۰.۰۰۹). In gingival margins, the least microleakage was recorded in group۲, while the most microleakage was found in group ۵ (P=۰.۰۰۱). Differences between ۵ study groups were statistically significant (P<۰.۰۵). The microleakage scores were higher at the gingival margins.CONCLUSION: The use of the Er:YAG laser for conditioning with different dentin adhesive systems influenced the marginal sealing of composite resin restorations. Keywords: Er-YAG Laser conditioning resin composite bonding agent