Tilted Implants in the Immediate Loading Rehabilitation of the Maxilla: A Systematic Review

Prosthetic rehabilitation of the atrophic maxilla with implant-supported prostheses frequently represents a challenge because of inadequate quantity and quality of bone. The use of distal tilted implants has been proposed as a viable alternative to traditional protocols. The aim of this meta-analysis was to evaluate the survival rate and bone reabsorption next to upright and tilted implants supporting full-arch fixed dentures for the immediate rehabilitation of edentulous maxillae, after at least 1 year of function. This review was conducted in accordance with the guidelines of Transparent Reporting of Systematic Reviews and Meta-analyses (PRISMA statement). An electronic search of databases plus a hand search of the most relevant journals in Oral Implantology was performed up to August 2011. Papers regarding immediate loading protocols of the edentulous maxilla using full-arch bridge supported by both up-right and tilted implants were selected. The literature search yielded 1069 articles. A first screening based on title and abstract identified 26 eligible studies. Finally, eleven articles were selected for analysis. One paper was a prospective cohort study, 7 were prospective single-cohort studies, and 3 had a retrospective design. A total of 1623 implants (778 tilted, 845 upright) were inserted in the maxilla of 324 patients. A total of 17 tilted (2.19%) and 16 upright implants (1.89%) failed during the first year. No significant difference in failure rate was found between tilted and upright implants (Pooled RR = 1.23 [95% CI: 0.66-2.30]; p-value = 0.52) and no heterogeneity between studies was highlighted (I2 = 0%). No prosthesis failure was reported. Marginal bone level results were obtained from 6 studies that showed results separated for tilted (n = 536) and upright (n = 539) implants in the maxilla. A non-significant mean difference between tilted and upright implants (MD = 0.02; 95% [CI: -0.05-0.09]; p-value = 0.58) was found. Some amount of heterogeneity between studies (I2 = 34.2%) was shown but no differences between results from fixed or random effects models were found. In conclusion, the use of tilted implants to support full-arch fixed prostheses for the immediate loading rehabilitation of edentulous maxillae can be considered a predictable technique, with an excellent prognosis in the short term. Randomized long-term trials are needed to determine the effectiveness of this surgical approach.