Objective: Polymer-infiltrated ceramics materials and glass ceramics are commonly used nowadays in dental field. However, their thickness is considered critical especially when applied in areas subjected to heavy forces. Thus, the purpose of this study was to assess the stresses induced in mandibular first molar restored by polymer-infiltrated ceramics and glass ceramic crown with different occlusal thicknesses (1 mm and 1.5 mm).
Materials and methods: A 3D finite element model of mandibular first molar restored with CAD/CAM lithium disilicate glass ceramic [LD; IPS e.max CAD] and polymer-infiltrated ceramic [VE; VITA Enamic] crowns with different occlusal thicknesses (1 and 1.5 mm) were constructed (Models: LD1, LD1.5, VE1, VE1.5). A static axial load (200 N) was applied in all groups. Using sophisticated finite element analysis software, von Mises stresses were assessed.
Results: The highest stress values in the restorations were in model VE1.5 followed by LD1, then LD1.5, and the least was VE1. LD caused more stresses in the underlying cement and periodontal ligament. However, crowns with 1.5mm occlusal thickness caused less stresses in the underlying cement, periodontal ligament and cancellous bone
Conclusions: The nature of the restorative material and the occlusal thickness affect stress distribution in teeth restored with full coverage crown