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Background: The aim of the current study was to evaluate the outcomes and complications of three-unit porcelain-fused-to-metal tooth-implant-supported prostheses in comparison with implant-supported prostheses. Materials and Methods: In this review article, the electronic databases, PubMed, Scopus, LILACS, Web of Science, EBSCO, LIVIVO, and Embase were searched over the past 20 years until December 2021. Risk ratio with 95% confidence interval (CI), fixed effect model, and Mantel–Haenszel method was calculated. The meta-analysis was performed with the statistical software Stata/MP v. 16. Results: Two hundred and three studies were selected for reviewing the abstracts, from which the full texts of 16 studies were reviewed. Finally, five studies were selected. The risk ratio of prosthesis failure between the tooth-implant-supported prosthesis and the implant-supported prosthesis was RR (Risk Ratio)= 1.83 (0.79, 4.24), ( P = 0.16) and for prosthesis complication, it was RR = 0.61 (0.35, 1.06), ( P = 0.08). Risk ratio of implant failure between the mentioned groups was RR = 2.33 (0.84, 6.41), ( P = 0.10), and for implant complications, this rate was 0.09 (RR, 0.09 95% CI − 1.30, 1.48; P = 0.90). Conclusion: The meta-analysis of the present study showed that there was no significant difference between the two groups (three-unit porcelain-fused-to-metal tooth-implant-supported prosthesis and implant-supported prosthesis reconstruction) in terms of the total failure of implants and prostheses and the complication rate of implants and prostheses.

Introduction. Discrepancy between the crown border and prepared tooth margin leads to a microleakage that eases the penetration of microorganisms and causes the dissolution of luting cement consequently. Several factors should be considered to achieve optimal fitness, including tooth preparation taper and type of cementing agent. The study aimed to determine the relation of tooth preparation taper and cement type on the microleakage of zirconia crowns. Materials and Methods. Fifty-six freshly extracted premolars without caries and restorations were selected as the study sample and divided into two groups of different tapering degrees (6 and 12 degrees). Zirconia copings were designed and fabricated by the CAD/CAM system. The samples were divided into four subgroups for cementation, and each subgroup was cemented with a different luting cement (n = 7). After 5000 thermocycles at 5°C–55°C and dye penetration, the specimens were sectioned in the mid-buccolingual direction, and a digital photograph of each section was taken under a stereomicroscope. Data were analyzed by the Kruskal–Wallis and Mann–Whitney tests (α = 0.05). Results. The results showed significant differences among the four types of luting cement in marginal permeability (PV < 0.001). Regardless of the type of cement, the 12-degree tapering resulted in a lower microleakage (46.4% without microleakage) with statistically significant differences from the 6-degree tapering (PV = 0.042). Conclusion. Within the limitations of this study, increasing the tapering degree of the prepared tooth for CAD/CAM zirconia copings improved the marginal fit and decreased the microleakage score. In addition, total-etch resin cement indicated the least microleakage.

In this research, silver-doped zinc oxide (SdZnO) nanoparticles (NPs) were synthesized in an environmental-friendly manner. The synthesized NPs were identified by UV-vis spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). Finally, the antimicrobial activity of synthesized ZnO and SdZnO NPs was performed. It was observed that by doping silver, the size of ZnO NPs was changed. By adding silver to ZnO NPs, the antimicrobial effect of ZnO NPs was improved. Antibacterial test against gram-positive bacterium Streptococcus mutants showed that SdZnO NPs with a low density of silver had higher antibacterial activity than ZnO NPs; Therefore, SdZnO NPs can be used as a new antibacterial agent in medical applications.

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