Effect of Placement Technique on Microleakage of Cervical Composite Restorations

"Objectives:" To investigate the effect of placement technique (bulk vs incremental) on the microleakage at enamel and dentin margins of class V composite restorations. "Methods:" Standardized class V cavities (6x2x2mm) were prepared in the buccal and lingual surfaces of 120 extracted molars. The gingival half of the preparations extended 0.5mm apical to the cemento-enamel junction and the walls finished to a butt joint. The teeth were randomly divided into 6 groups of 20, each group was equally divided into two subgroups: (a) restored by bulk placement; (b) restored by incremental technique using 6 composites namely Arabesk, Silux-Plus, Solitaire 2, Durafill VS, Charisma and Renew. The composite was either placed in bulk or in 2 consecutive layers and light polymerized according to manufactures’ recommendations. The teeth were stored in distilled water at room temperature for 24h, thermocycled for 500 cycles between 5 and 55°C at a dwell time of 30s and then immersed in 1% methylene blue for 4h. The teeth were sectioned bucco-lingually and examined at 4x magnification using a Stereomicroscope. Dye penetration (DP) was scored as follows: "score 0" no DP, "score 1" DP up to half the length of the walls, "score 2" DP along the entire length of the occlusal or gingival interface not reaching the axial wall, "score 3" DP reaching the axial wall. Data was analyzed using the Generalized Linear Models (GENMOD) Statistical test at P < 0.05. "Results:" The restorative technique, material type and preparation orientation had no significant effect on microleakage scores (P=0.5914, 0.1811 and 0.8417, respectively). The type of tooth structure (enamel/dentine) was the only factor significantly affecting microleakage (P=0.0026). "Conclusions:" There was no difference between the incremental and bulk placement techniques in terms of microleakage at the enamel and dentine margins of class V cavities restored using the above mentioned composites.