Radiographic view of adhesive layer andrelationship with marginal leakage in class II composite resin restorations

ABSTRACT

This study assessed the influence of the application of bonding agents prior to or after matrix and wedge placement in the radiographic view of the adhesive layer in cervical walls of Class II composite resin restorations and correlated the findings with marginal leakage. Standard cavities were prepared in the mesial and distal faces of human molars, with cervical margins placed in dentin/cementum. Restorations were made using metallic matrix bands and wooden wedges. The microhybrid composite Filtek Z250 (3M ESPE) and two adhesive systems – Single Bond 2 (SB-3M ESPE) and Scotchbond Multi-Purpose (SMP-3M ESPE) – were used, thus defining five groups (n= 12): [SB1] and [SMP1]- matrix and wedge placed after bonding application; [SB2] and [SMP2]-matrix and wedge placed prior to bonding application; [Control] – restorations without adhesive system. Bitewing radiographs from each tooth were obtained and the view or not of the adhesive layer in the cervical wall of each restoration was observed under magnification (40x). Specimens were thermalcycled and dye penetration (0.5% basic fuchsine) evaluated under magnification (40x). Data were submitted to Kruskal-Wallis and Spearman correlation tests (p=0.05). The placement of matrix and wedge before bonding agent application increased the view of the adhesive layer only for SB (p<0.001). Matrix did not influence marginal leakage, and no significant relationship between radiographic view of adhesive layerand marginal leakage (r=-0.020; p =0.877) could be observed. In conclusion, SB presented better sealingability than SMP (p<0.01).