A microleakage study of ceramic laminate veneers by autoradiography: effect of incisal edge preparation

The purpose of this study was to evaluate the microleakage characteristics of laminate veneers with different incisal edge preparation. Two groups of 20 extracted human maxillary central incisors were used for fabricating laminate veneers. The cervical margin of all veneers were placed 1 mm above the cementoenamel junction. The incisal finish line of 20 teeth was placed at the incisal edge (window type preparation). The incisal finish line of the other 20 teeth was placed linguoincisally (incisal edge overlapped type preparation). All veneers were fabricated according to the manufacturer's instructions with vacuum fired porcelain and cemented with dual-cure resin cement. The autoradiographic method was used for determination of microleakages. Microleakages at the interface of the laminate veneer and tooth were determined according to the scale described in the manuscript. Mc Nemar test was used for comparison of microleakages at cervical margins. Microleakage grades at other areas were compared in percentage. In the two preparation types the cervical microleakages were of similar degree. The incisal microleakages in the overlapped laminate veneers were greater than in the window type veneers. In conclusion, the window preparation type was more effective in terms of prevention of microleakage at the incisal margin than the overlapped type laminates.