Technical complications and failures of zirconia-based prostheses supported by implants followed up to 7 years: a case series.

PURPOSE: To evaluate technical complications and failures of zirconia-based fixed prostheses supported by implants. MATERIALS AND METHODS: Consecutive patients received zirconia-based single crowns (SCs) and fixed dental prostheses (FDPs) on implants in a private clinical setting between 2005 and 2010. One dentist performed all surgical and prosthetic procedures, and one master technician performed and coordinated all laboratory procedures. One-piece computer-aided design/ computer-assisted manufacture technology was used to fabricate abutments and frameworks, which were directly connected at the implant level, where possible. All patients were involved in a recall maintenance program and were finally reviewed in 2012. Data on framework fractures, chipping of veneering ceramics, and other technical complications were recorded. The primary endpoint was failure of the prostheses, ie, the need for a complete remake. A life table analysis was calculated. RESULTS: A total of 289 implants supported 193 zirconia-based prostheses (120 SCs and 73 FDPs) in 127 patients (51 men, 76 women; average age: 62.5 ± 13.4 years) who were reviewed in 2012. Twenty-five (13%) prostheses were cemented on 44 zirconia abutments and 168 (87%) prostheses were screw-retained directly at the implant level. Fracture of 3 frameworks (1 SC, 2 FDPs) was recorded, and significant chipping resulted in the remake of 3 prostheses (1 SC, 2 FDPs). The 7-year cumulative survival rate was 96.4% ± 1.99%. Minor complications comprised 5 loose screws (these were retightened), small chips associated with 3 prostheses (these were polished), and dislodgement of 3 prostheses (these were recemented). Overall, 176 prostheses remained free of technical problems. CONCLUSIONS: Zirconia-based prostheses screwed directly to implants are clinically successful in the short and medium term.

Zirconia for teeth and implants: a case series.

This case series reports on the use of nonsilica-based high-strength full ceramics for different prosthetic indications. Fifty-two consecutive patients received tooth- or implant-supported zirconia reconstructions during a 2-year period. The observation period for reexamination was 12 to 30 months. The most frequent indications were single crowns and short-span fixed partial dentures. A few implant superstructures were screw-retained, whereas all remaining restorations were cemented on natural teeth or zirconia implant abutments. Clinical examination included biologic (probing depths, bleeding on probing) and esthetic (Papilla Index) parameters, as well as technical complications. No implant was lost or caused any problems, but two teeth were lost after horizontal fracture. Overall, the periodontal parameters were favorable. Fractures of frameworks or implant abutments were not observed. Abutment-screw loosening occurred once for one premolar single crown. Furthermore, five implant crowns in the posterior region exhibited chipping of the porcelain veneering material. With regard to esthetics, no reconstructions were considered unacceptable, but three crowns were remade shortly after delivery. In this short-term study, it was observed that biologic, esthetic, and mechanical properties of zirconia were favorable, and the material could be used in various prosthetic indications on teeth or implants.

A follow-up study of maxillary implants supporting an overdenture: clinical and radiographic results.

PURPOSE: Studies of maxillary overdentures supported by endosseous implants often show a high implant failure rate. The aim of the present investigation was to evaluate clinically and radiographically non-submerged implants supporting an overdenture in the maxilla. MATERIALS AND METHODS: Forty-one patients were consecutively admitted for treatment. The standard procedure was to place 4 implants and to mount a U-shaped bar for overdenture connection. When the overdenture was delivered to the patients, peri-implant parameters were recorded and radiographs were taken. All patients were required to follow a maintenance care program. In the context of this study, all patients were clinically examined and the peri-implant parameters were compared. Crestal bone loss was analyzed using linear radiographic measurements. A life table analysis was applied to calculate the cumulative survival rate (CSR). RESULTS: Three implants failed in the early healing phase, and 3 patients lost 6 implants during the loading period. The 5-year CSR of all implants was 94.2%. The peri-implant parameters gave evidence of healthy soft tissues and good oral hygiene. The increases in probing depths and attachment loss were significant (P < .05). The mean marginal crestal bone loss was about 0.7 mm and was statistically significant at mesial and distal sites (P < .001). DISCUSSION: The correlation between clinical attachment loss and crestal bone loss was not significant. Pronounced marginal bone loss was found around some implants. CONCLUSION: In planned maxillary overdenture treatment, it is possible to achieve a satisfactory survival rate of the implants.