The effect of sodium hypochlorite on microleakage of composite resin restorations using three adhesive systems.
OBJECTIVE
The aim of this study was to evaluate the effect of three different adhesive systems on microleakage of Class V restorations after the use of sodium hypochlorite.


METHODS
One-hundred eighty bovine incisors were selected and randomly divided into 9 groups (n = 20): G1: Single Bond (SB); G2: 10% NaOCl solution (NS) + SB; G3: 10% NaOCl gel (NG) + SB; G4: Prime & Bond NT (PB); G5: NS + PB; G6: NG + PB; G7: Gluma One Bond (GOB); G8: NS + GOB; G9: NG + GOB. Standardized Class V cavities were prepared. All teeth were etched with 37% phosphoric acid for 15 s. In groups 2, 5, and 8, a 10% NaOCl solution was applied for 60 s to the dentin, and in groups 3, 6, and 9, a 10% NaOCl gel was applied to dentin for 60 s. All cavities were restored with composite resin Definite. The specimens were thermocycled for 1000 cycles (5 degrees C to 55 degrees C) and then immersed in 2% buffered solution of methylene blue for 4 h. The specimens were sectioned and analyzed according to a ranking score (0 to 4). Kruskal-Wallis and Mann-Whitney non-parametric tests (p < or = 0.05) were used for statistical analysis.


RESULTS
The NaOCl treatment significantly increased microleakage at the dentin margin (p = 0.0129) as shown by the following sums of ranks: G1 = 1008.0a; G4 = 1301.5ab; G3 = 1687.0ab; G7 = 1744.0bc; G2 = 1802.0c; G9 = 1880.0c; G5 = 1889.0c; G8 = 1950.0c; G6 = 1963.0c (different superscripts indicate significant differences). For enamel, there were no statistically significant differences among the groups (p > 0.05).


CONCLUSIONS
Depending on the adhesive system used, the application of NaOCl increased microleakage along dentin margins.
Department of Restorative Dentistry, School of Dentistry of Piracicaba, University of Campinas, Piracicaba, São Paulo, Brazil.
Mirela Sanae
MS
Shinohara
Ana Karina Barbieri
AK
Bedran-de-Castro
Cristiane Mariote
CM
Amaral
Luiz André Freire
LA
Pimenta
D000134:Acid Etching, Dental / Q000379:methods*; D000269:Adhesives / Q000737:chemistry; D000818:Animals; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002417:Cattle; D004396:Coloring Agents; D003188:Composite Resins / Q000737:chemistry*; D003737:Dental Cavity Preparation / Q000145:classification; D003763:Dental Leakage / Q000145:classification*; D003793:Dental Restoration, Permanent / Q000145:classification*; D003804:Dentin / Q000648:ultrastructure; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D008422:Materials Testing; D008751:Methylene Blue; D016877:Oxidants / Q000737:chemistry*; D010756:Phosphoric Acids / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D011897:Random Allocation; D019279:Resin Cements / Q000737:chemistry; D012833:Siloxanes / Q000737:chemistry; D012973:Sodium Hypochlorite / Q000737:chemistry*; D018709:Statistics, Nonparametric; D013696:Temperature; D013729:Terpenes / Q000737:chemistry
D000269:Adhesives; D004396:Coloring Agents; D003188:Composite Resins; C421785:Definite composite resin; D017220:Dentin-Bonding Agents; C408265:Gluma One Bond; D016877:Oxidants; D010756:Phosphoric Acids; D011109:Polymethacrylic Acids; C425843:Prime and Bond NT; D019279:Resin Cements; D012833:Siloxanes; D013729:Terpenes; C115612:single bond; D017438:Bisphenol A-Glycidyl Methacrylate; D012973:Sodium Hypochlorite; D008751:Methylene Blue