Fracture resistance of endodontically treated teeth of different ferrule lengths restored with all ceramic crowns using two types of posts

Abstract

The fracture resistance of endodontically treated and treated teeth has always been unpredictable. This present study was designed to evaluate the effect of ferrule existence and the effect of post type on the fracture resistance of endodontically treated teeth. The total of 30 intact upper central incisors were collected and divided according to ferrule existence into 3 groups: • Group1: 10 teeth with ( 2mm ferrule ) The crowns of the teeth were sectioned horizontally 2 mm cronal to the cej, and roots were endodontically treated. Group 1: was further subdivided according to post type into :  G1a-roots restored with taperad fiber post and composite core (5 teeth )  G1b-roots restored with parallel fiber post and composite core (5 teeth) All teeth restored with all ceramic crown • Group 2: 10 teeth with (1mm ferrule ) The crowns of the teeth were sectioned horizontally 1mm cronal to the cej, and roots were endodontically treated. Group 2: was further subdivided according to post type into :  G 2a- roots restored with taperad fiber post and composite core (5 teeth)  G 2b-roots restored with parallel fiber post and composite core (5 teeth) All teeth restored with all ceramic crown • Group 3: 10 teeth with ( zero ferrule) The crowns of the teeth were sectioned horizontally at the cej , and roots were endodontically treated. Group 3: was further subdivided according to post type into :  G3a-roots restored with taperad fiber post and composite core (5 teeth )  G3b-roots restored with parallel fiber post and composite core (5 teeth) All teeth restored with all ceramic crown All teeth were embedded in acrylic resin blocks and mounted in a specially designed block holder . This block allowed the loading of the teeth at a 45 degrees angle at their longitudinal axes. The point of load application was 2 mm below the incisal edge on the palatal surface. A continous increasing compressive force was delivered through a specially designed applicator connected to a universal testing machine at a cross head speed of 0.5 \ min till failure occurs. The results of this study revealed that the 2mm ferrule group sample G1 were higher fracture resistance than 1mm ferrule group sample G2 than zero ferrule group sample G 3 It was also found that the tapered fiber post restored samples recorded higher fracture resistance than the parallel fiber post restored samples. The mode of failure of tapered post with 2 mm ferrule was 60% favourable mode and 40% non favourable . While 1mm ferrule 80% favorable and 20 %unfavorable. While zero mm ferrule all samples were favorable mode of failure . Also the mode of failure of parallel post for all samples was favorable whether in 2mm, 1mm, zero mm ferrule . The fracture pattern of most samples was repairable without involvement of post fracture, core fracture or all ceramic crown fracture.