Evaluation of the fracture strength of porcelain sectional veneers made from different sintered feldspathic porcelains: An in vitro study

Background. Porcelain sectional veneers with no preparation (no-prep) are an ultra-conservative choice for the esthetic treatment of the anterior teeth. They can be made from a sintered feldspathic porcelain, which gives a great appearance with small thickness, but there are still concerns about the fracture strength of this material. Objectives The aim of this study was to evaluate the fracture strength of porcelain sectional veneers made from 2 different sintered feldspathic porcelains. Material and methods Twenty recently extracted human incisors were randomly divided into 2 groups according to the porcelain material (n = 10). The 1st group was applied the IPS Style (R) Ceram feldspathic porcelain and the 2nd group - GC Initiar MC. The porcelain sectional veneers were fabricated following the manufacturers' instructions. After the veneers bonded with resin cement (Variolink (R) N), the fracture strength was measured using a universal testing machine (Instron (R) 1195) at 1 mm/min until failure occurred. Failure modes were determined under a stereomicroscope. Results. The mean fracture strength for group IPS Style Ceram was higher than that for group GC Initial MC (182.7 N and 155.7 N, respectively). The lowest value was observed in group IPS Style Ceram (78 N) and the highest value - also in the group IPS Style Ceram (294 N). Student's t-test demonstrated no statistically significant differences between the 2 groups (p > 0.05). Conclusions. There was no difference in the fracture strength of the porcelain sectional veneers for the 2 types of sintered porcelain used in this study. Cohesive failure within the porcelain sectional veneer was the most common mode of failure.