Prosthetic complications of fixed dental prostheses supported by locking-taper implants: a retrospective study with a mean follow-up of 5 years.

BACKGROUND: Restoration with locking-taper implants is a widely used methodology. However, conical connection systems such as locking-taper implant systems have rarely been examined. This study provides a retrospective investigation of locking-taper fixed restorations, mainly focusing on prosthetic complications. METHODS: Patients undergo treatment with conical connected implants from 2008 to 2010 were examined. Preparation of the implant sites was performed according to the standard procedures for the Bicon system. Bone healing took over 6 months, and the prosthetic procedure was initiated thereafter. Integrated abutment crowns or gold porcelain crowns were used, and the prosthesis type was a single crown or a fixed dental prosthesis. Once the crown was in place, its occlusion was thoroughly checked and adjusted, and then the crown was glazed or finely polished. The Kaplan-Meier method was used to calculate the cumulative complication-free rates for 5 and 10 years. Additionally, a Cox regression model was used to identify the factors that independently influenced the results. Implant survival and marginal bone loss were also investigated. RESULTS: A total of 392 patients who underwent 541 implants and 434 locking taper implant-based restorations from 2008 to 2010 were examined. The overall 5-year cumulative complication-free rate was 83.34%. The most common prosthetic complication was veneer chipping, with a frequency of 67.53%. According to the Cox regression model, the complication-free rate of integrated abutment crowns was significantly higher than that of gold porcelain crowns, that of molar regions was significantly higher than that of premolar regions, and that of females was significantly higher than that of males. Only three implant failures happened, and the mean marginal bone loss values at 1- year, 5-years and 10- years were 0.25 mm (95% CI ± 0.12), 0.40 mm (95% CI ± 0.03) and 0.51 mm (95% CI ± 0.05), respectively. CONCLUSION: Veneer chipping was the most common complication with locking-taper implant-supported fixed restorations. The incidence of complications for IACs is significantly higher than that for GPCs. Age, location, and prosthesis type are not determinants of prosthetic complications. Besides, the long-term clinical effect of locking-taper implant can meet the clinical needs. The bone tissue level around the implant can maintain long-term stability.

Antagonist Wear Of Zirconia Fixed Restorations In Vitro And In Vivo- A Systematic Review.

PURPOSE: To evaluate the wear of zirconia on natural teeth in humans in vitro and in vivo. MATERIALS AND METHODS: Embase, the Cochrane Database, PubMed, and the Web of Science were searched (January 2014 to May 2019), and all references were retrieved. After preliminary screening of the literature, two researchers read the full texts of the remaining literature and determined whether the literature should be included. Data and information were extracted from the included literature, then analyzed and discussed. RESULTS: A total of 49 in vivo experiments and 229 in vitro experiments were retrieved. After duplication removal and screening, 7 in vivo studies and 13 in vitro studies were included. The results of the in vitro studies showed that fine polished zirconia causes less antagonist wear on natural teeth than other treatments with zirconia or other restorative materials. The results of the in vivo studies showed the antagonist wear of zirconia on natural teeth was within the clinically acceptable range. CONCLUSION: Both in vivo and in vitro studies have shown polishing can reduce the wear of zirconia on natural teeth more than glazed or veneering porcelain. However, whether glazed zirconia causes less natural tooth wear after polishing is still a matter of debate. Due to the short observation period and heterogeneity of the experiment, the above conclusions should be carefully interpreted.