Patient satisfaction and survival of maxillary overdentures supported by four or six splinted implants: a systematic review with meta-analysis

Abstract

Background Implant-supported overdentures offer enhanced mechanical properties, which lead to better patient satisfaction and survival rates than conventional dentures. However, it is unclear whether these satisfaction levels and survival rates depend on the number of implants supporting the overdenture. Therefore, this systematic review aimed to compare maxillary overdentures supported by four or six splinted implants in terms of patient satisfaction, implant survival, overdenture survival, and prosthodontic complications. Methods Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (PubMed), and EMBASE databases were systematically searched and complemented by hand searching from 2000 to 2019, employing a combination of specific keywords. Studies comparing the use of four versus six implants for supporting overdentures with at least one-year of follow-up after prosthesis installation and including ten fully edentulous patients were included. The risk of bias (RoB) was analyzed with Cochrane’s RoB 2 and Newcastle–Ottawa tools. Implants and prosthesis survival rates were analyzed by random-effects meta-analysis and expressed as risk ratios or risk differences, respectively, and by the non-parametric unpaired Fisher’s test. Results A total of 15 from 1865 articles were included, and reported follow-up times after implant placement ranged from 1 to 10 years. Irrespective of the number of implants used, high scores were reported by all studies investigating patient satisfaction. Meta-analysis and non-parametric Fisher’s test showed no statistical differences regarding the survival rate of implants (P = 0.34, P = 0.3) or overdentures (P = 0.74, P = 0.9) when using 4 versus 6 splinted implants to support overdentures, and no significant differences regarding prosthodontic complications were found between groups. Randomized studies presented high RoB and non-randomized studies presented acceptable quality. Conclusions Within the limits of this systematic review, we can conclude that the bar-supported overdenture on four implants is not inferior to the overdenture supported by six implants for rehabilitating the edentulous maxilla, in terms of patient satisfaction, survival rates of implants and overdentures, and prosthodontic complications.

Implant-Retained Maxillary and Mandibular Overdentures - A Solution for Completely Edentulous Patients

“…According to the literature in case of maxillary overdenture with both implant and soft tissue support four to six implants are needed for retention and stability [51,54,55]. In case of four implants reduction in palatal plate of the denture is reported and recommended (Figures 9 and 10) [56,57].…”

Implant-Supported Hybrid Prosthesis using All on Six Concept for Atrophic Ridges with Severe Gag Reflex: A Case Report

“…The major drawbacks of implant dentistry are complex procedure, extended treatment time and expensive. Advances in implant dentistry now provides optimal cost-benefit ratio by invention of "all on 4" and "all on 6" implant rehabilitation procedures which allows for the same advantage of aesthetics and support that can be obtained from traditional implants with reduced expenditure and number of visits [4].…”

TMJ & Its role in Prosthodontia: A Systematic Review

“…Several papers suggested that the relationship between TMDs and dental occlusion is weak. 20,21 Nevertheless, patients with TMD symptoms often need a prosthetic treatment, including partial edentulism, esthetic deficiencies, or functional problems. 21,22 Those patients should be managed carefully after a detailed evaluation.…”

“…[21][22][23] Different studies introducing iatrogenic changes to dental occlusion reported some interesting considerations. 20,21 Furthermore, as far as bruxism is concerned, several systematic reviews analyzing implant-supported restorations suggest that bruxism may be associated more with mechanical than biological causes. [24][25][26][27]…”