INTRODUCTION: The laminate veneer technique bonds a thin ceramic laminate to the tooth surface with resin cements to restore anterior teeth. A vital importance is attributed to the strength and durability of the adhesion complex. OBJECTIVES: The aim of this study was to evaluate the shear bond strength of ceramic laminate veneers to two different tooth substrates (Enamel and Enamel-Dentine complex), with different luting systems. MATERIALS AND METHODS: Sixty extracted human maxillary central incisor teeth were used, and randomly divided according to tooth surface preparations into two main groups (n=30); Group A in Enamel (E) only and Group B in Enamel-Dentin complex (E-D), each group was then subdivided according to the type of resin cement received (Light cure LC or Dual cure DC) into four sub groups of 15 specimens each: Group A 1:(E + LC); Group A 2:(E + DC); Group B 1:(E-D + LC); Group B 2:(E-D + DC). Ceramic discs (IPS e.max Press, IvoclarVivadent) of 4 mm in diameter and 2 mm in height were luted to the tooth surfaces by using the resin cement (Variolink Esthetic ® , IvoclarVivadent) according to the manufacturers' instructions. Shear bond strength test was performed in a universal testing machine at 0.5 mm/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 analyzed (p≤0.05). RESULTS: Group B 1 exhibited the lowest bond strength value(9.12±4.86MPa). There was statistically no difference among A 1,A 2 and among B 1,B 2(p>0.05).Group A 2 exhibited the highest bond strength value (14.73± 5.83MPa). CONCLUSIONS: The type of tooth substrate affected the shear bond strength of the ceramic laminate veneers to the 2 different types of tooth structures (Enamel, Enamel-Dentine complex).

Introduction: the aim of this in vitro study was to evaluate push-out bond strength and interfacial adaptation to dentine wall of EndoSequence BC (BC) and MTA Fillapex sealers compared to AH Plus sealer (AH+). Methods: sixty-six human extracted single rooted teeth with single root canal were selected and the crowns were removed at the level of CEJ to standardized the roots length (16 mm). Samples were instrumented using ProTaper universal NiTi rotary system up to size F5. After irrigation and smear layer removal samples were randomly divided according to tested sealer used into three groups of 22 sample each, and then obturated using lateral compaction technique and stored for 1 week before testing. Each group was subdivided according to test into two subgroups of 11 sample each, push-out test or interfacial adaptation. Data were statistically analyzed by one-way ANOVA and Tukay's post-hoc test (P≤0.05). Results: AH Plus has a statistically significant higher bond strength value than each of EndoSequence BC group and MTA Fillapex group. Regarding interfacial adaptation there was no statistically significant difference between the three sealers. Conclusion: EndoSequence BC bioceramic sealer, MTA Fillapex MTA based sealer showed their inferiority regarding push-out bond strength when compared to AH Plus resin based sealer. All of the three sealers showed different grades of gap width along the whole length of root canal wall.