This systematic literature review set out to investigate the relationship between serum vitamin D levels and dental implants in terms of survival rates, marginal bone loss, and associated complications. The review was conducted according to PRISMA guidelines, performing an electronic search in four databases (Pubmed, Web of Science, Cochrane, and Scopus), complemented by a manual search up to April 2022. Four articles were selected for analysis. The Newcastle-Ottawa Quality Assessment Scale tool was used to assess the quality of evidence of cohort studies, and the Cochrane bias assessment tool was used to assess the quality of evidence of randomized clinical trials. The study included 1089 patients restored with 1984 dental implants, with follow-up periods ranging from 20–240 months. Cases presenting lower serum vitamin D levels obtained slightly worse results in terms of marginal bone loss. Longer follow-up periods are needed in order to determine whether serum vitamin D levels affect implant survival rates and osseointegration over time.

Background/Objectives: Subperiosteal implants (SPIs) were first used in the 1940s, but due to their complications and the rise of dental implants, they were discontinued. Thanks to new technologies and new materials, nowadays they are being used again and studied as a treatment for severe bone defects. This review analyzes the clinical results—survival rates and complications—of SPIs used to support full arch rehabilitations of severely resorbed maxillae and mandibles, comparing the outcomes resulting from implant placement conducted in one or two surgical interventions. Methods: An automated search was conducted in four databases (Medline/Pubmed, Scopus, Web of Science, and Cochrane Library), as well as a manual search for relevant clinical articles published before 28 February 2025. The review included human studies with at least four patients, in which SPIs were placed to restore full-arch edentulous maxillae and mandibles. Quality of evidence was evaluated using the Newcastle–Ottawa Quality Assessment Scale and the Joanna Briggs Institute Critical Appraisal tool. Results: A total of 14 studies met the inclusion criteria and were included for analysis, including 958 patients and 973 SPIs. The survival rate was 100% when one surgical intervention was performed and 85% when two interventions were performed after 4–38 months and 3–22 years follow-up, respectively. Conclusions: SPIs would appear to offer a good alternative for patients with severe bone atrophies, especially SPIs fabricated using digital techniques in a single step, presenting promising survival rates and a low complication rate, although more randomized clinical trials with long-term follow-up are needed.

Background/Objectives: Titanium implants remain the gold standard in implant dentistry. However, growing interest in metal-free alternatives has led to increased use of zirconia implants. Despite encouraging short-term outcomes, evidence regarding the medium- to long-term survival of one-piece zirconia implants (O-PZIs) and associated risk factors remains limited. The aim of this retrospective cohort study was to evaluate the survival of O-PZIs over follow-up periods of up to 8 years and to explore variables potentially associated with implant failure. Methods: This retrospective observational cohort study was conducted at a private dental clinic (Madrid, Spain). A total of 307 O-PZIs placed in 196 patients between 2017 and 2021 were analyzed. Implant survival was assessed using Kaplan–Meier analysis, while associations between clinical variables and implant failure were explored using chi-square tests and multivariate Cox regression models (p < 0.05). The mean follow-up period was 61.37 ± 2.25 months. Results: After a mean follow-up of 61.37 ± 2.25 months (range: 39–96 months), 42 failures were recorded, resulting in a cumulative survival rate of 86.32% (CI 95%: 79.28–92.96%). Most failures (64.29%) occurred before prosthetic loading. Kaplan–Meier analysis revealed significantly lower survival for tapered implants (p < 0.001) and among smokers (p < 0.001). Multivariate analysis indicated that only simultaneous guided bone regeneration (GBR) was independently associated with implant failure (Exp(B) = 3.191; 95% CI: 1.299–7.840; p = 0.011). However, this association should be interpreted with caution due to the retrospective design, potential confounding, limited number of events, and lack of adjustment for clustering at the patient level. The discrepancies observed between statistical methods highlight the importance of time-to-event analyses in implant research. Conclusions: Within the limitations of this study, O-PZIs demonstrated acceptable medium- to long-term survival. Simultaneous GBR may be associated with increased risk of failure. However, these findings should be considered exploratory. Further prospective studies are required to confirm these results and to better define risk factors in ceramic implant therapy.