Evaluation of Fracture Resistance of Some Contemporary Class II Glass Ionomer Restorations at Different Time Intervals

Purpose: was to evaluate and compare fracture resistance of some contemporary glass ionomer restorations (Amalgomer CR, EQUIA Fort fil and EQUIA fil) in class II cavities at different time intervals. Materials and Methods: A total of 90 class II cavities were prepared in extracted maxillary premolars (n=90).   The samples were divided into three main groups (30 each) according to the materials; These three groups were further subdivided into three groups according to assessment time; 24 hours, one month and three months. Each material was applied to the cavity according to manufactures’ instructions. Samples were stored in artificial saliva for the study storage periods. At the end of each storage period samples were subjected to thermocycling at 5˚C and 55˚C for 1000 cycles. The samples were subjected to fracture resistance test using universal testing machine. Failure modes were evaluated using stereomicroscope and micromorphology of fractured restorations and tooth restoration interface were evaluated using Scanning Electron Microscope (ESM). Results: the results revealed that the highest mean value recorded for Amalgomer CR followed by Equia Fort fil while Equia fil recorded the lowest mean value. Also the results revealed that the highest mean value recorded after three months storage followed by one moth storage while one month storage recorded the lowest mean value. Conclusions: Fracture resistance of cone temporary glass ionomers in class II cavities is affected by storage for 3 months. Ceramic reinforced glass ionomer (Amalgomer CR) appears promising regarding fracture resistance.