Effect Of Different Preparation Extensions On Fracture Resistance Of Endo-crowns Fabricated With Two Ceramic Materials Restoring Premolar Teeth (In Vitro Study)

Abstract

This study was conducted to evaluate the effect of three different intrapulpal depths (2mm, 4mm, 6mm) with two ceramic materials(Vita Enamic, Vita Suprinity) On fracture resistance of endo-crowns restoring premolars teeth under loading. Forty two intact, non-carious, human premolars without any obvious cracks, were extracted for orthodontic reasons were randomly assigned to three groups of 14 teeth each, the two groups were sub divided into two sub groups of 7 teeth each A surveyor was used to ensure upright position of teeth in molds which were filled with non-shrink epoxy resin material placing the margin of the epoxy resin below the cemento-enamel junction by 1mm and parallel to the epoxy resin.Then the crown portion of all premolars were removed to within 3 mm above the CEJ Mesio-Distally . Specimens were divided into three groups according to the type of preparation extensions done, Group A (2 mm intrapulpal depth), Group B (4 mm intrapulpal depth), Group C (6 mm intrapulpal depth). Then Each group was subdivided into two sub-groups according to the type of preparation extension done, Subgroup I (Enamic), Subgroup II (Suprinity).