Fracture Resistance of Endodontically Treated Maxillary Premolars Restored by Various Direct Filling Materials: An In Vitro Study

Abstract

The aim of this study is to compare the effect of various restorative materials on fracture resistance in maxillary premolars. Premolars (n=64) with no restorations or cracks were selected. MOD cavities were prepared considering the buccolingual width to be equal to half of the intercuspal distance. The specimens were randomly divided into 8 groups, 8 specimens each:group Aintact teeth,group Bunfilled cavity,group Ccomposite made by oblique layering technique,group Dcomposite with 2 mm cusp coverage,group Ebulk-filled posterior composite,group Fglass-ionomer,group Gamalgam, andgroup Hcomposite with proximal boxes. The specimens were subjected to an axial compression load with the mean values of fracture resistance in group A: 1289 N, group B: 181.75 N, group C: 445.38 N, group D: 645.88 N, group E: 355.13 N, group F: 352.00 N, group G: 191.38 N, and group H: 572.00 N. There was no significant difference between groups B and G, between C and D, E, and F, and between group D and H. All other measurements were statistically significant. We conclude that composite restoration with cusp coverage is the most ideal nonprosthetic solution for endodontically treated teeth. Cusp coverage increases the fracture resistance compared to the conventional cavity design.