Clinical internal and marginal gap of porcelain laminate veneers with minimal tooth preparation and without tooth preparation and 2-year clinical evaluation

Irregularities affecting the esthetic view of maxillary anterior region can be corrected with several prosthetic treatment options such as crowns and porcelain laminate veneers (PLV). The first choice of treatment had been crowns for many years. However, today this technique is considered as invasive approach. Minimal invasive (minimal tooth preparation and no tooth preparation) PLVs are good and conservative treatment choice for esthetic corrections at maxillary anterior region; however, no study comparing marginal and internal adaptation of minimal invasive PLVs (minimal tooth preparation vs no tooth preparation) has been published. Therefore, the aim of this clinical study were to compare marginal and internal three-dimensional (3D) adaptation of PLVs with minimal tooth preparation and without tooth preparation (prepless) using micro CT and to evaluate the clinical outcomes. Thirty-one prepless PLVs and 31 PLVs with minimal tooth preparation were fabricated using lithium disilicate glass ceramic material and placed in 12 patients. A silicone replica was obtained to measure marginal and internal adaptation of each PLV just before luting using a low viscosity polyvinyl siloxane impression material. Silicone replicas were scanned in X-ray micro computed tomography (micro CT). Clinical evaluations took place at baseline (2 days after luting) and at 6, 12, and 24 months after luting. Esthetic, functional and biological properties were evaluated following FDI criteria. There was statistically significant difference with respect to marginal gap and internal adaptation between 2 groups. Because no restoration required replacement during 2 years, the overall survival rate of the 62 PLVs was 100% according to the Kaplan-Meier survival estimation method. Keywords: Porcelain laminate veneers; minimally invasive therapy; marginal adaptation; internal adaptation.