Comparative evaluation of the bond strength of posterior composite with different cavity configurations and different liners using a two-step etch and rinse adhesive system: In vitro study

INTRODUCTION: Conventional Class II cavity preparations used for restoring small lesions with amalgam may be inappropriate for composite resin restorations due to the extensive cavity form, large occlusal contact area, and thin or missing margins of the tooth. Cavity preparation in the proximal areas as per the precepts of Clark is a conservative method of caries excavation and tooth preparation. MATERIALS AND METHODS: Conventional Class II and Clark's Class II cavities were prepared on the mesial surfaces of 60 molars. All cavities were given a standard buccolingual width of 2 mm, an occlusogingival height of approximately 3.5 mm and an axial depth of 1.5 mm. These were then restored using flowable composites or resin-modified glass-ionomer cement liners and nanohybrid composites. The compressive bond strength was tested with a universal testing machine. RESULTS: The compressive bond strength was the highest for Clarks Class II cavity preparation with a lining of flowable composites. Conventional Box only Class II cavities restored with flowable liners showed the next best result. CONCLUSION: Clark's class II cavity preparation can be used as efficiently as the conventional Class II box preparation with the advantage of preserving more tooth structure, more precise tooth preparation, good bond strength and better esthetics.