Resistance to fracture of crowned endodontically treated premolars restored with ceramic and metal post systems.

OBJECTIVES: The objective of this study was to assess the resistance to fracture of crowned endodontically treated premolars with varying ceramic and metal post systems under simulated occlusal load. METHOD AND MATERIALS: The study consisted of 60 extracted intact premolars with similar root diameter and length. Teeth were divided equally into 4 groups (n = 15) and prepared for posts and cast crowns as follows: group 1 = preformed metal post, composite core, and cast crown; group 2 = cast post and core and cast crown; group 3 = zirconia post, composite core, and cast crown; and group 4 = zirconia post and heat-pressed ceramic core and cast crown. All prepared teeth had 2 mm of sound dentin on which the cast crowns were cemented. A continuous load (kg) was applied by an Instron testing machine to the buccal cusp at a 30-degree angle to the long axis of each tooth at a crosshead speed of 2 mm/min until failure. One-way analysis of variance with Scheffe test was used to statistically compare the differences between groups. RESULTS: Mean failure loads (in newtons) for the 4 test groups were as follows: 1,103.3 (group 1), 1,234.5 (group 2), 826.6 (group 3), and 870.6 (group 4). No significant difference in failure load values was found among all tested groups (F[3,59] = 2.05; P >.05). The primary mode of failure (85%) in all groups was an oblique radicular fracture, either apical to the post or at the post level. Horizontal fracture (15% to 20%) of the root and post was found in groups 3 and 4. CONCLUSION: Within the limitations of this study, varying ceramic and metal post systems did not affect the failure resistance of teeth restored with full-coverage cast metal crowns, under simulated occlusal load.

Wide-diameter implant placement and internal sinus membrane elevation in the immediate postextraction phase: clinical and radiographic observations in 12 consecutive molar sites.

PURPOSE: To evaluate whether the combination of 5 surgical techniques in implant dentistry could be performed simultaneously in a predictable manner as effectively as each technique separately. MATERIALS AND METHODS: Immediately postextraction, 12 wide-diameter (WD) implants were placed in maxillary first or second molar sites. The residual vertical bone height ranged between 6 and 9 mm (average 7.8 mm). An internal sinus elevation, via the osteotomy site, was carried out in 10 sites using an osteotome tool implants were then self-tapped into the osteotomy site followed by Insertion of a customized healing screw. Consequently, horizontal gaps between the bony walls and the implant neck were filled by either bovine bone mineral or tricalcium phosphate particles. Full soft tissue closure around the healing cap screw was achieved by coronal positioning of the buccal flap. RESULTS: Soft tissue healing around the 12 implants was immaculate. In 10 sites, Internal osteotome sinus membrane elevation resulted in a height gain of between 2.5 and 6 mm (average 4.3 mm). Radiographically, bone-to-implant contact was evident. All implants were integrated and the prosthetic phase was completed after 6 months. DISCUSSION AND CONCLUSIONS: The combination of 1-stage technique and immediate placement of WD implants, along with internal sinus floor elevation and no soft tissue reflection at the time of implantation, is an achievable task and can be performed predictably. Time, cost, and morbidity are reduced, and the prosthetic solution is also eased for the benefit of the patient.