The adhesive potential of dentin bonding systems assessed using cuspal deflection measurements and cervical microleakage scores

Abstract

ObjectivesTo assess the cuspal deflection and cervical microleakage of standardized mesio-occluso-distal (MOD) cavities restored with a dimethacrylate resin-based-composite (RBC) placed with one 3-step, one 2-step and three 1-step bonding systems and compared with the unbound condition. MethodsForty-eight sound maxillary premolar teeth with standardized MOD cavities were randomly allocated to six groups. Restoration was performed in eight oblique increments using a quartz-tungsten-halogen (QTH) light curing unit (LCU) with the bonding condition as the dependent variable. Buccal and palatal cuspal deflections were recorded post-irradiation using a twin channel deflection measuring gauge at 0, 30, 60 and 180s. Following restoration, the teeth were thermocycled, immersed in a 0.2% basic fuchsin dye for 24h, sectioned and examined for cervical microleakage assessment. ResultsThe mean total cuspal deflection measurements with the one 3-step, one 2-step and three 1-step bonding systems were 11.26 (2.56), 10.95 (2.16), 10.03 (2.05) (Futurabond® DC SingleDose), 6.37 (1.37) (Adper™ Prompt™ L-Pop™), 8.98 (1.34) μm (All-Bond SE®), respectively when compared with the unbound condition (6.46 (1.88) μm) The one-way ANOVA of the total cuspal deflection measurements identified statistical differences (p<0.001) between groups. Cervical microleakage scores significantly increased (p<0.001) for the negative control (unbound condition) when compared with teeth restored with a bonding system although differences between the bonding systems were evident (p<0.001). SignificanceThe cuspal deflection and cervical microleakage protocol reported offers an opportunity to test the bonding technologies available to practitioners for RBCs. Poorly performing adhesives can be identified which indicated the technique may be useful as a screening tool for assessing existing and new bonding technologies which offers the potential to limit complications routinely encountered with Class II RBC restorations.