Evaluation of the stress concentration of different incisal ridge preparations of porcelain veneers (Finite element analysis)

Abstract

Background: Porcelain veneers are under a great deal of stress which may lead to clinical failure as fracture ordettachment. This study examined whether different finishing lines and lingual shoulder preparations in the incisalarea of the maxillary central incisor affect the bond of the porcelain veneers.Materials and methods: A two- dimensional finite element model was made. Location and magnitude of maximumVon Mises stresses were calculated in porcelain veneer. Six types of preparations were drawn as:incisal overlap of0.5mm, 1mm and 1.5mm depth and lingual shoulder, and incisal overlap of 0.5mm, 1mm and 1.5mm depth withoutshoulder preparation.Results: Stress formation is maximum in the incisal edge region. All the lingual shoulder preparations presented betterstress distribution than the non shoulder preparationsConclusion: Stress is distributed more evenly when the tested preparation possesses a good thickness of porcelainand the more the surface area with incisal overlap the less possibility of bond failure