The Effect Of Residual Root's Surface Shape On The Resistance To Fracture Of Endodontically Treated Teeth Restored With Post

Objective:To study the effect of residual root's surface shape on the resistance to fracture of endondontically treated teeth restored with post.Methods:The experiments were performed with a homogeneous sample of twenty-four intact single-rooted human maxillary first premolars of similar dimensions,all recently extracted from adolescents who were receiving orthodontic treatment.After endodontically treated by the manual lateral condensation method,the teeth were randomly distributed into 3 epual groups of 8 specimens:In Group A the anatomic crowns of all teeth were sectioned vertically to the long axis,2mm coronal tissue to the CEJ with a water spray-cooled diamond at high speed.Teeth were restored with castmetal post.In Group B the anatomic crowns of all teeth were sectioned vertically to the long axis,2mm coronal tissue to the CEJ and were prepared with two inclined planes with a water spray-cooled diamond at high speed.The distance between CEJ and planes was 1mm. Teeth were restored with castmetal post.In Group C the anatomic crowns of all teeth were sectioned vertically to the long axis,2mm coronal tissue to the CEJ and were prepared.The prepared residual root's surface was rounded with dentine. Teeth were restored with castmetal post.All cast post were luted with a glass ionomer cement(3M Dental Products).Then all specimens were deeped into solved wax and taken out immediately .This design simulated the periodontal membrane.Specimens were embedded vertically in autopolymerizing acrylic resin surrounded by metal cylinders with 2cm diameter,which had a flat surface 2mm below the facial CEJ.This design simulated the natural biologic width.Spesimens were secured in CMT5105 Electromechanical Universal Testing...