Influence of Different Marginal Preparation Designs on the Fracture Resistance of Vita Ambria and Vita Suprinity Endocrowns (An In Vitro Study )

Aim: This study evaluated the fracture resistance of endocrowns with two marginal preparation designs and manufactured with two all ceramic materials.Methods: Twenty endodontically treated maxillary premolar teeth were prepared to receive endocrown restorations and divided into two equal main groups according to the preparation designs; endocrowns with butt joint design and endocrowns with ferrule design (n=10). The main groups were subdivided into two equal subgroups according to all ceramic material used; endocrowns manufactured from Vita Ambria and endocrowns manufactured from Vita Suprinity (n=5). The endocrown restorations were cemented to the prepared teeth using dual cured self-adhesive resin cement. The specimens were subjected to thermo-cycling. All specimens were subjected to a compressive force until fracture by using universal testing machine. The maximum compressive force was recorded for all the specimens, then the failure modes were examined using a digital microscope.Results: Regarding the two materials effect, there were non-significant difference between Vita Ambria and Vita Suprinity on fracture resistance (P=0.66). Regarding the two marginal preparation designs effect, there were non-significant difference between butt joint and ferrule designs on fracture resistance (P=0.73). Regarding the failure mode, there was non-significant difference between all failure mode patterns in all groups except Vita Suprinity with butt joint design.Conclusion: There was no significant difference between Vita Ambria and Vita Suprinity endocrowns, either using ferrule or butt joint design in this study.