title: Leakage pathway of Class V cavities restored with different flowable resin composite restorations.
abstract: This study investigated the leakage pathway of facial and lingual Class V cavities restored with different flowable resin composites bonded with one bonding agent by examining the resin/dentin interface. Forty Class V cavities were etched with 37% phosphoric acid gel; Single Bond dental adhesive was applied, then the cavities were randomly divided into four groups (n=10). Three groups were restored with one of three flowable resin composites (Grandio Flow, Filtek Flow and Admira Flow). The fourth group was restored with Z250 (hybrid resin composite) to serve as a control. The specimens were then placed in 50% w/v silver nitrate solution for 24 hours and immersed in a photodeveloping solution for eight hours. Thereafter, the specimens were sectioned bucco-lingually, polished, mounted on stubs, gold sputter coated and examined by scanning electron microscope. Silver particle penetration length with and without gap formation was measured directly on the scanning electron microscope monitor and calculated as a percentage of the total length of the cut dentin surface that was penetrated by silver nitrate. The data were analyzed with one-way ANOVA and Tukey HSD test. The groups restored with Filtek Flow and Admira Flow showed a microleakage pattern where silver nitrate penetration was observed with gap formation at the tooth/restoration interface and Filtek Flow recorded significantly higher leakage than Admira Flow. Grandio Flow showed similar marginal adaptation to Z250 resin composite with no gap formation at the interface. However, silver ions had penetrated beneath the resin-impregnated layer in cavities restored with Grandio Flow and Z250, indicating nanoleakage occurred. This study suggests that volumetric shrinkage in resin composites remains a problem. Although some new technologies are trying to solve the problem of composite shrinkage, the bonding system used in this study did not achieve perfect sealing at the restoration/dentin interface. This might affect durability of the bond to dentin.
authors.affiliation: Department of Restorative Dental Science, College of Dentistry, King Saud University, Riyadh, Saudi Arabia. wawliya@hotmail.com
authors.forename: Wedad Yassin
authors.initials: WY
authors.lastname: Awliya
authors.forename: Ali M
authors.initials: AM
authors.lastname: El-Sahn
mesh_terms: D000704:Analysis of Variance; D017438:Bisphenol A-Glycidyl Methacrylate; D003188:Composite Resins; D003737:Dental Cavity Preparation; D003738:Dental Cements; D003763:Dental Leakage; D018772:Dental Marginal Adaptation; D003793:Dental Restoration, Permanent / Q000379:methods*; D003799:Dental Stress Analysis; D017220:Dentin-Bonding Agents; D006801:Humans; D008855:Microscopy, Electron, Scanning; D008964:Molar, Third; D044367:Phase Transition; D019279:Resin Cements; D016622:Silver Staining
chemical_list: D003188:Composite Resins; D003738:Dental Cements; D017220:Dentin-Bonding Agents; C467913:Filtek Flow; D019279:Resin Cements; C525452:admira flow; C115612:single bond; D017438:Bisphenol A-Glycidyl Methacrylate