SPLINTED AND UNSPLINTED SHORT IMPLANTS IN MANDIBLES: A RETROSPECTIVE EVALUATION WITH 5 TO 16 YEARS OF FOLLOW-UP

Background: The aim of this retrospective study was to investigate the medium- to long-term prognosis of short implants in partially and totally edentulous patients with mandibular bone atrophy. Methods: The study involved 109 patients with 280 implants placed in the mandible. The implants were 7 or 8.5 mm long and 3.75 or 4 mm in diameter. The fixture surfaces were machined (M) and rough (R) for 176 and 104 implants, respectively. Patients were asked to attend a radiographic and clinical follow-up and their previous clinical records and X-rays were assessed. Implant-related and prosthetic failures, and complications were recorded. Results: The mean follow-up was 9 years (range 5-16 years). The survival rate (SSR) and success rate (SR) were calculated using life table analysis, for both M and R short implants. The M implants had a 16-year SSR of 95.7% and a corresponding SR of 93.9%, while the 16-year SSR and SR for the R implants were 97.2% and 95.2%, respectively. The mean bone resorption for all implants was 1.37 mm (SD 0.5 mm). As regards marginal bone loss (MBL), there was no statistically significant difference between the two implant lengths (p=0.38) or diameters (p=0.34), or between the M and R implant surfaces (p=0.47). Conclusions: Different implant lengths, diameters, and surface treatments do not appear to influence the implant's prognosis. Within the limitation that most of the short implants were splinted to longer implants, the reduced length of the fixtures did not worsen the long-term survival of the implant-supported fixed prostheses.