Fracture Localisation of Porcelain Veneers with Different Preparation Designs

BACKGROUND: Porcelain veneers are permanent restorations that combine good aesthetic with functionality by minimal destructive techniques. AIM: This study aimed to investigate the influence of the preparation designs on the fracture localisation. MATERIAL AND METHODS: Three preparation designs of porcelain veneers fabricated by a method of laying on a fireproof abutment on maxillary central incisor were examined in this in vitro study-feather preparation, bevel preparation and incisal overlap – palatal chamfer. The samples from all three groups were loaded into a universal test machine-TRITECH WF 10056 until damage occurred on the porcelain veneer. Fracture localisation was classified as an incisal, gingival or combination. Data were analysed with statistical programs: STATISTICA 7.1; SPSS 17.0. RESULTS: In feather preparation, as a consequence of the mechanical force, the most common is the incisal localisation (66.7%), followed by the combined (33.3%), while the gingival fracture localisation is not registered. In bevel preparation, the most common fracture localisation is combined (53.6%), followed by incisal (35.7%) and subsequent gingival localisation (10.7%). In incisal overlap (palatal chamfer), combined and gingival localisation of the fracture is equally recorded in 14.3% of the samples, while the incisal is the most common localisation and is registered in 72.4%. CONCLUSION: During the study, a statistically significant dependence was found between the localisation of the occurred changes (incisal, gingival and combination) and the three different types of preparation.