Failure Load of Maxillary Central Incisor Restored with CAD/CAM Endocrown Using Different Designs

Abstract

Statement of problem: Restoration of a severely destructed non-vital tooth is usually challenging, especially, in case of incomplete circumferential tooth structures. Materials and methods: Sixty intact maxillary central incisors were collected. All teeth were decoronated leaving 2 mm above the CEJ then were divided into two divisions (30 specimens for each) according to the radicular depth (2 mm &4 mm). Each division was divided into three groups (10 specimens for each) according to residual coronal tooth structures (circumferential, only labial and only palatal) to obtain six groups of testing. Then milling was done for (IPS e.max CAD) followed by final cementation. Fracture resistance was tested using a universal testing machine. Results: Specimens restored with endocrowns having 2 mm radicular length, exhibited fracture resistance better than that with 4 mm radicular length, without statistical significant difference. Endocrowns with 2 mm circumferential residual coronal tooth structures in both radicular lengths exhibited fracture resistance better than that having either labial or palatal residual coronal tooth structures with a statistically significant difference. The specimens having 2 mm labial residual coronal tooth structures in each radicular length exhibited fracture resistance better than that with 2 mm palatal residual coronal tooth structures in each radicular length with a statistically significant difference. Conclusion: For restored endodontically treated maxillary central incisor by endocrown: residual 2 mm circumferential wall presented better fracture resistance than that with only residual labial or palatal wall and residual labial wall presented better fracture resistance than the palatal wall.