Total bonding vs selective bonding: Marginal adaptation of class 2 composite restorations

For improving the marginal integrity of composite restorations, a total bon ding method has been advocated besides the conventional selective bonding m ethod. Total bonding avoids the placement of a base. The entire internal ca vity surface is available for the adhesive bond. Selective bonding involves the placement of a base covering the pulpal floor as well as the pulpoaxia l wall. In this study, five dentin/enamel bonding system/composite combinat ions were used to restore 60 class 2 cavities with their cervical margins b elow the cementoenamel junction (CEJ); six teeth per material were restored according to the total bonding and the selective bonding methods. Before a nd after simultaneous thermocycling and mechanical loading (TCML) marginal adaptation was evaluated on replicas in the SEM. Microleakage was determine d by dye penetration on the original samples after TCML. The data were stat istically evaluated with the Mann-Whitney U-test and the Wilcoxon test. The error rates method was applied. In SEM analysis the error rates method ind icated a significant difference between the two restoration methods in gene ral. In the pairwise comparisons, no significant differences between the se lective bonding and total bonding methods were found for Syntac/Tetric, Glu ma 2000/Pekafill, and Gluma/Pekafill. With Scotchbond Multi-Purpose (SBMP) and All-Bond 2 (AB2), total bonding revealed significantly (P less than or equal to 0.01) less gap formation before and after TCML than selective bond ing. Accordingly, total bonding showed significantly less (P less than or e qual to 0.01) dye penetration with Scotchbond Multi-Purpose and All-Bond 2 compared to selective bonding. In conclusion, the reduction of microleakage by application of the total bonding method depended upon the bonding syste m used. Total bonding could be an alternative procedure for the adhesive re storation of class 2 cavities when their gingival margins are apical to the cementoenamel junction, provided the proper system is used and pulp damage is prevented.