Investigation of the fracture resistance of endodontically treated teeth with mesio-occluso-distal (MOD) cavity preparations with fiber insertion

One of the most important factors affecting the success of the endodontically treated teeth is the quality of the final restoration and its resistance to occlusal stresses. The aim of this study was to investigate the effect of fiber reinforcement on the endodontically treated teeth with MOD cavity preparations which have high post operative fracture frequency. 135 intact and non carious human maxillary premolar teeth, extracted for orthodontic reasons, were used in this study. After root canal treatment MOD cavities were prepared. Two experimental groups were assigned by using polyethylene and glass fibers and each group was placed 4 different positions as gingival, middle, occlusal and circumferential. No fiber group was served as control. Vertical comppressive force was applied at a cross-head speed of 0.5mm/min using universal test machine until fracture and the values obtained were recorded in Newtons. The data was analyzed by using Mann Whitney U test and Kruskal Wallis test. When the results obtained from our study were examined; the use of polyethylene and glass fiber was found to increase the fracture strength of maxillary premolar teeth with MOD cavities statistically (p <0.05). When both fiber groups were compared with each other, there was no statistically significant difference; but the values obtained from glass fiber groups were higher than the average fracture values obtained from polyethylene fiber groups (p> 0.05). This study concluded that the use of both polyethylene and glass fiber mesh increased the fracture resistance of the restoration of endodontically treated teeth with MOD cavities.