Volumetric Analysis of Peri-implant Tissue Change Over Time: Validating an Innovative 3D Method.

PURPOSE: To validate an innovative 3D volumetric method of evaluating tissue changes proposed by Lee et al in 2020 by comparing the results of this method-in which the scanned peri-implant surfaces were transformed, visualized, and analyzed as 3D objects-to the results reported by an existing method based on calculation of the mean distance between measured surfaces. The null hypothesis was that there was no statistically significant difference between the two methods. Additionally, the present study evaluated peri-implant tissue changes 5 years after single implant placement in the esthetic zone. MATERIALS AND METHODS: Both methods were applied to 11 oral implant site casts (6 maxillary central incisor sites, 5 maxillary lateral incisor sites) taken from 11 patients at crown placement and at follow-up examinations 5 years later. The methods are based on digital workflows in which the reference and 5-year casts are scanned and the resulting STL files are superimposed and analyzed for three regions of interest (mesial papilla, central area, and distal papilla). The volumetric changes reported by the Lee et al method and the mean distance method were calculated and compared using the Spearman rank correlation coefficient (P < .01) and the Wilcoxon signed-rank test (P < .05). RESULTS: The correlation between the two sets of measurements was very high (Spearman rank correlation coefficient = 0.885). The new volumetric method indicated a mean volume loss of 2.82 mm3 (SD: 5.06), while the method based on the measurement of mean distance showed a mean volume loss of 2.92 mm3 (SD: 4.43; Wilcoxon signed-rank test result: P = .77). No statistically significant difference was found. The two methods gave equivalent results, and the null hypothesis was accepted. CONCLUSIONS: The new volumetric method was validated and can be considered a trustworthy tool.

Prosthetic failures in dental implant therapy.

Both fixed and removable implant-supported prostheses are well-established methods for replacing missing teeth in partially or fully edentulous patients. Numerous systematic reviews have been performed in recent years to evaluate the survival and complication rates of implant-retained fixed dental prostheses and implant-retained overdentures, displaying high 5-year survival rates ranging from 97.1% for fixed dental prostheses to 95%-100% for implant-retained overdentures. However, the survival rates only represent the prostheses remaining in use for a defined follow-up time, and do not account for the potential prosthetic complications that may have arisen and influence the general success of the implant treatment. The most common technical complications of fixed implant-retained single crowns are crown fracture, fractures of ceramic implant abutments, and esthetic problems. The predominant technical complication at multiple-unit, implant-retained fixed dental prostheses is fracture/chipping of the veneering ceramic. Reported technical complications for implant-retained overdentures are overdenture fracture or chipping of the veneer materials, whereas mechanical complications include implant fracture, attachment failure, and attachment housing or insert complications. To reduce the risk of such failures, a comprehensive pretreatment diagnostic work-up is essential, including defining the prosthetic goal with the aid of a wax-up or set-up and the associated ideal, prosthetically oriented three-dimensional implant position. Furthermore, selection of the ideal type of prosthesis, including the respective implant components and materials, is important for clinical long-term treatment success.

The Influence of Patient-Related Factors and Material Selection on the Clinical Outcomes of Fixed and Removable Complete Implant Prostheses: An Overview on Systematic Reviews.

PURPOSE: To analyze the influence of material selection, attachment type, interarch space, and opposing dentition on the prosthetic outcomes of fixed and removable implant complete prostheses (FCIPs and RCIPs, respectively). MATERIALS AND METHODS: This review was designed as an overview of systematic reviews. An electronic database search was performed to identify scientific literature that reported on FCIPs and RCIPs. The last search was performed in January 2020. The final inclusion of systematic reviews for data extraction was decided by consensus of the authors. The included studies were analyzed qualitatively. RESULTS: A total of 21 systematic reviews (FCIP: n = 11, RCIP: n = 10) out of 5,733 articles initially identified were included for data extraction and interpretation. High overall 5-year and 10-year prosthesis survival rates were shown for FCIPs and RCIPs (93.3% to 100% and 96.9% to 100%, respectively). Chipping/fracture of the veneering material was the most frequent technical complication for FCIPs, and attachment-related complications were the main technical problems for RCIPs. For FCIPs, the effect of prosthetic material was not significant on the technical complications nor the survival rates. No studies were identified that provided direct information on the effect of interarch space in FCIPs and RCIPs. CONCLUSIONS: Both FCIPs and RCIPs obtained high overall survival rates, but technical complications cannot be avoided with either prosthesis type. No prosthetic material can be considered as the material of choice over another. Attachment type has no influence on the overall clinical outcomes of RCIPs. The influence of opposing dentition and the required prosthetic space were not investigated sufficiently.