The effect of modified access cavity preparations by preventing oblique ridge and using flowable composite of fracture resistance in distally decayed maxiller first molar teeth after endodontic treatment

The aim of this study was to eveluated the effect of modified access cavity preparations by preventing oblique ridge and using flowable composite of fracture resistance in distally decayed maxiller first molar teeth after endodontic treatment140 noncarious maxiller first molar teeth were used. 20 teeth were allowed for negative control. Teeth were randomly divided into two groups. In the first group cavities were prepared protecting oblique ridge and in the second group oblique ridge were removed. The root canals were enlarged with K files to size 40. Each group was divided into three subgroups randomly. One each subgroup was allowed for positive control. Other teeth root canals were filled with gutta-perca and AH plus. Glass ionomer cement was used for base material. We used 1mm flowable composite for base material one each subgroups. Teeth, which root canals were filled, restorated with composite resin. All teeth were embedded in the acrylic resin and subjected to an increasing compressive force with 1 mm/min until fracture occurred by using universal testing machine. The data were recorded and statistical analyses were made with Tukey and Bonferroni. Finite element analyses models were created in a computer. Tooth structures?s and material?s values were transferred to the computer and force appliedThe group which protecting oblique ridge and using flowable composite were found better than other groups which have been cavity preparations. Finite element analyses results were similar to these findingsProtecting oblique ridge and using fowable composite were increased teeth?s fracture resistance.