MICROLEAKAGE OF CLASS-II BOX-TYPE COMPOSITE RESTORATIONS

Purpose: TO investigate whether in small box-type Class II preparation s the use of glass ionomer cement, a dentin primer or a different type of conditioner had an effect on the microleakage compared to a more s imple total-etch system using a phosphonated bonding agent. Materials and Methods: In extracted premolars, 84 hox-type Class II composite re sin restorations with margins in enamel were made following a standard ized protocol. A transparent matrix system was used and the composite resin was applied in two layers. The teeth were restored using a phosp honated total-etch bonding system as a control (Photo Bond). In the ex perimental groups a glass ionomer lining-cement (Vitrebond), a total-e tch adhesive including a primer (Scotchbond Multi-Purpose) and a total -etch adhesive using a self-etching primer (Liner Bond 2) were used. T he teeth were thermocycled, immersed in a dye solution and sectioned. The cervical and occlusal dye penetration was assessed. Results: Preve nting microleakage was not more effective in the experimental groups t han in the control group (P<0.05). Scotchbond MP groups using maleic a cid showed statistically significant more microleakage than the contro l group (Photo Bond) at the cervical side. Liner Bond 2 and Scotchbond MP groups using maleic acid showed statistically significant more mic roleakage than the control group at the occlusal side. The use of a li ning cement did not improve the quality of the restoration. From this study it was concluded that in this type of restoration, total-etch sy stems using a primer are not always an improvement.