Influence of Screw Channel Angulation on the Fracture Resistance of Zirconia Abutments: An In Vitro Study.

PURPOSE: The aim of this study was to investigate the effect of implant screw channel angulation on the fracture resistance of zirconia abutments without artificial aging. MATERIALS AND METHODS: Ten implant replicas were embedded in a jig of autopolymerizing acrylic resin. Using a surveyor and a metallic platform, the implant replicas were mounted centrally and with an angulation of 30°. A maxillary left central incisor crown was fabricated from pattern resin and scanned. The digital design of a monolithic zirconia implant abutment-crown was completed using a 3D imaging software. For all specimens of this group (ASC25 ), the screw channel was positioned at 25° to the lingual. Following fabrication, the samples were attached onto the embedded implant replicas and manually torqued to 35 Ncm as recommended by the manufacturer. The monolithic zirconia implant abutment-crowns were mounted in a metallic platform, positioned perpendicular to the indenter, and subjected to loading until failure. Crosshead speed was set at 0.5 mm/min for the universal testing machine. Data from a similar in vitro study where straight zirconia custom abutments (ASC0 ) were subjected to static load until failure was used as a control group. An unpaired Student's t-test was used to determine if fracture resistance based on load at failure and maximum load in each group were significantly different from each other (ASC25 vs ASC0 ). Statistical significance level was inferred at p ≤ 0.05 RESULTS: Group ASC25 fractured at a mean (SD) load of 215.49 (47.10) N and a mean (SD) maximum load of 420.50 (17.18) N. Group ASC0 fractured at a mean (SD) load of 534.04 (133.77) N and a mean (SD) maximum load of 762.69 (109.59) N. The difference was statistically significant for both mean load and mean maximum load at failure (p ≤ 0.05). The survival rate of 0° zirconia abutments was significantly higher than that of 25° ASC zirconia abutments. CONCLUSIONS: Within the limitations of this in vitro study the mean fracture load was significantly higher in the group with a straight channel angulation.

Use of a surgical template for minimally invasive second-stage surgery: A dental technique.

The introduction of new techniques and new technology has been directly related to successful outcomes in implant dentistry. Merging information from high-quality cone beam computed tomography images and detailed prosthetically driven digital planning translates into computer-guided surgery. A surgical template is a guide used to assist in the proper surgical placement and angulation of dental implants. However, a surgical guide not only facilitates implant placement but can also be used for other purposes, including diagnosis, treatment planning, and even second-stage surgery. In situations where multiple implants have been placed through computer-guided implant surgery, the preexisting surgical template can be used to perform the second-stage surgery with a flapless approach if the patient's soft tissue condition permits.

Oral Care Program for Successful Long-Term Full Mouth Habilitation of Patients with Hypohidrotic Ectodermal Dysplasia.

Hypohidrotic ectodermal dysplasia (HED) is a rare congenital disorder that associates with dental manifestations of anodontia, hypodontia, and atrophic alveolar ridges. Although the disorder does not affect the life expectancy of the patient, it poses tremendous challenges on the patient's physical and psychosocial development. Early and multidisciplinary dental care can benefit HED children's development and improve their quality of life. This study presents two cases addressing the dental management continuously for 10 to 13 years in the dental school clinics. The keys to long-term success of the oral care program for HED patients at different age phases are reviewed and discussed, which can be summarized as early intervention, multidisciplinary collaborative care, and continuous recall.