Effect of laminate veneer designs on abfraction incidence using different loading conditions “finite element analysis”

Statement of problem: Abfraction incidence is usually challenging and difficult to be identified accurately, especially, in case of existing restoration.
Aim of the study: This study aimed to evaluate the influence of laminate veneer design on abfraction incidence in maxillary central incisor with different loading protocols using finite element analysis.
Materials and methods: Maxillary central incisor was subjected to Computerized tomography (CT) scan to obtain 3D finite element model. Tooth without restoration (control) was subjected to a load of 100 N at 60° and 125°, the same load was applied with the previous directions on the tooth model with lithium disilicate laminate veneer using three preparation designs: veneer is taken up to the incisal edge level but the edge, is not reduced (Feather) (FP), design (FP) is prepared with 0.5mm incisal reduction without palatal overlapping (Butt joint.) (BJP) and (POP) in which, design (FP) is prepared with 2 mm incisal reduction and 0.5 mm palatal overlap.
Results: In feather preparation (FP) design, stress values were slightly higher than that in control model in enamel and dentin at both load directions. While, but joint preparation (BJP) design exhibited the lowest stress in both layers and direction of load.
Conclusion Highest stresses were concentrated at the cement – enamel junction in all loading scenarios, butt joint preparation (BJP) design in both load conditions developed lower stresses than that in other designs, and feather preparation (FP) design suggested the probability of abfraction formation.