Shear bond strength of porcelain laminate veneers to enamel, dentine and enamel–dentine complex bonded with different adhesive luting systems

Abstract

ObjectivesThe aim of this study was to evaluate the shear bond strength of porcelain laminate veneers to 3 different surfaces by means of enamel, dentine, and enamel–dentine complex. MethodsOne hundred thirty-five extracted human maxillary central teeth were used, and the teeth were randomly divided into 9 groups (n=15). The teeth were prepared with 3 different levels for bonding surfaces of enamel (E), dentine (D), and enamel–dentine complex (E–D). Porcelain discs (IPS e.max Press, Ivoclar Vivadent) of 2mm in thickness and 4mm in diameter were luted to the tooth surfaces by using 2 light-curing (RelyX Veneer [RV], 3M ESPE; Variolink Veneer [VV], Ivoclar Vivadent) and a dual-curing (Variolink II [V2], Ivoclar Vivadent) adhesive systems according to the manufacturers’ instructions. Shear bond strength test was performed in a universal testing machine at 0.5mm/min until bonding failure. Failure modes were determined under a stereomicroscope, and fracture surfaces were evaluated with a scanning electron microscope. The data were statistically analysed (SPSS 17.0) (p=0.05). ResultsGroup RV-D exhibited the lowest bond strength value (5.42±6.6MPa). There was statistically no difference among RV-D, V2-D (13.78±8.8MPa) and VV-D (13.84±6.2MPa) groups (p>0.05). Group VV-E exhibited the highest bond strength value (24.76±8.8MPa). ConclusionsThe type of tooth structure affected the shear bond strength of the porcelain laminate veneers to the 3 different types of tooth structures (enamel, dentine, and enamel–dentine complex). Clinical significanceWhen dentine exposure is necessary during preparation, enough sound enamel must be protected as much as possible to maintain a good bonding; to obtain maximum bond strength, preparation margins should be on sound enamel.