[ effects of adhesive type and different curing methods on micro leakage and marginal adaptation of composite veneers]

ABSTRACT

The adhesives type and placement application technique may be important in long term stability and function of composite veneers. This study was conducted to evaluate the influence of dentin adhesive application techniques [pre-curing vs. non-curing] on micro leakage and marginal adaptation of indirect composite veneer restorations. A total etch bonding system, Excite/Variolink II [EXV], and a self-etching primer system, Panavia F 2.0 [PF2] were used in this in-vitro investigation. Forty-eight human central incisors were prepared for composite veneer restoration. These teeth were then divided into two groups [n=24]. Pre-cure adhesive [PC] with light cure technique as well as no pre-cure [NPC] prior to resin cement insertion in half of specimens in each group. By using these methods, we worked with four experimental subgroups [PC+EXV, NPC+EXV, PC+PF2, NPC+PF2]. Composite veneers [Tetric Ceram resin] were cemented using a dual-cured resin luting agents. All specimens were then stored in distilled water at 37°C for 24 hours before checking for marginal leakage. By random sampling, two specimens were selected from each group for SEM observations and evaluation of marginal adaptation at 1050 time magnifications. Data was analyzed by ordinal regression and link function of probit type at alpha leakage values were observed in dentinal margins of NPC+EXV and PC+EXV subgroups respectively. A significant difference was observed between dentinal and enamel margins on micro leakage values of PC and NPC groups [P<0.05], meaning that, precure adhesive was more effective than resin cements alone. No adhesive layer was observed in non precured adhesive specimens. The effect of pre-curing adhesive was not material specific. The pre-cured adhesives showed the best resistance to dye penetration, although the film thickness of luting agent was slightly increased