Comparative Evaluation of Stress Values in Different Class II Cavity Designs Restored with Composite and Amalgam Using Finite Element Analysis – An in-vitro study

Abstract

OBJECTIVES: To compare the stress values in class II Mesio-occlusal (MO) and class II Disto-occlusal (DO) cavities in mandibular first molar restored with composite and amalgam using FEA.  

MATERIALS AND METHODS: Three-dimensional models for Finite element analysis (FEA) was developed by scanning an extracted mandibular using Cone Beam Computed Tomography (CBCT). The following types of FEA models were created: Unprepared and Unrestored Molars; Class II MO & DO cavities - Amalgam restoration; Class II MO & DO cavities- Composite restoration. A masticatory load of 200N was applied to the buccal cusp tip, as well as on the mesial and distal ridges, along the long axis of the tooth. The distribution of stress in dentin and enamel was examined. Dynamic loading was also evaluated by mimicking normal cyclic loading of the individual. Stress was analysed after cyclic as well as dynamic loading. The following parameters were analysed for the stress distribution: Total deformation; Equivalent elastic strain; Equivalent elastic stress; Safety factor due to impact and cyclic loading; Life Time of the restored tooth due to cyclic loading; Damage due to cyclic loading. The values were tabulated.

RESULTS: Class II cavities restored with composite resin had less stress values and more life span when compared to amalgam restorations. Class II mesio-occlusal cavities showed less stress values than the class II disto-occlusal cavities.

CONCLUSION: Class II MO cavities showed less stress values than DO cavities. Composite had less total deformation, less equivalent stress and strain values with more life span and less damage when compared to amalgam. Both amalgam and composite restorations exhibited high safety factor