Evaluation of the survival rate of short implants placed in the posterior atrophic mandible: 5-year clinical study

Objective: The aim of the study was to assess the long-term prognosis of short implants (5 to 6 mm) placed in the posterior region of the atrophic mandible. Method and materials: The study included 81 patients with severe vertical atrophy of the bone in the posterior region. The patients had 248 short implants (5 to 6 mm) implants placed in the mandibular posterior region and 256 implants with length greater than 10 mm in the mandib-ular anterior region. Analysis of implant and prosthesis failures, cumulative survival rate, and marginal bone loss was determined at 1 year and 5 years of follow-up (58 +/- 7 months). Results: Mean marginal bone loss after 1 year of prosthetic loading was 0.74 mm for short implants and 0.72 mm for implants with length greater than 10 mm; after 5 years of prosthetic loading this was 1.27 mm for short implants and 1.31 mm for implants with length greater than 10 mm. Of 248 short implants (5 to 6 mm), six failed: four due to peri-implantitis and two due to lack of osseointegration (early rejection). Of 256 implants with length greater than 10 mm, five failed: three due to peri-implantitis and two due to lack of osse-ointegration (early rejection). On average, over the observation period (58 +/- 7 months), the 5-year cumulative implant survival rate was 97.8% in short implants, and 98.1% in longer implants; the prosthesis cumulative survival rate was 98.2%. Conclusions: Based on the results, it was concluded that the prognosis of the use of short implants for prosthetics in the posterior resorbed mandible can be considered favorable and reasonable.