Evaluation of Shear Bond Strength of Ceramic Laminate Veneers Prepared by Two Different Designs. An in Vitro Study

Ceramic laminate veneers are widely used in dentistry as an esthetic solution for patient with problem in appearance. The main mode of failure with bonded ceramic veneer is fracture and bond failure. To achieve proper bonding between ceramic restoration and tooth so as to evaluate the shear bond strength of ceramic laminate veneer.

To evaluate the shear bond strength of ceramic laminate veneers prepared by two different designs that are bonded on extracted human maxillary central incisors.

In this study, 24 extracted human maxillary central incisors with approximately 10 mm anatomic crown length; homogenous mesio-distal width are selected. Specimens randomly divided into 2 groups. In Group I tooth preparation done in facial reduction, without incisal reduction with feathered incisal edge. In Group II tooth prepared by facial reduction with 1mm incisal reduction with 1mm palatal chamfer. All groups are cemented with VARIOUNK N dual cure resin cement (IVOCLAR VIVADENT, LIECHTENSTEIN). Fracture loads were recorded with a mechanical testing machine.

Statistical analysis is done with Independents Test and Mann-Whitney U Test. Evaluate the frequency of veneer failure modality was done by Chi-square test. The mean Stress at Max. Load (MPa) is greater in group-l than in group-ll. The difference between means are statistically significant (P=0. 001).

Ceramic Laminate Veneer preparation without incisal involvement would be a better design as the Palatal extension in group II did not contribute to the strength of the restoration but only had an adverse effect.