Extra-short implants in the posterior region: A case series of single and multi-unit fixed prostheses

Aim Anatomical and surgical conditions may require the use of implants with reduced length. This study reports a case series of patients treated with single or multi-unit fixed prostheses supported by 4-mm implants in the posterior region. The aim was to describe the success rate up to four years of loading, and the mechanical and biological complications.

Materials and methods The sample consisted of all patients treated with prostheses supported by 4-mm implants at the Military Policlinic of Porto Alegre, Brazil, between the years 2015 and 2019. The patients were recalled for clinical examination and data collection: The type of prosthesis, maximum bite force, presence of bruxism, peri-implant bone level, and crown-implant ratio were recorded.

Results Eight patients with 19 implants in the premolar and molar region were examined. Eleven implants were rehabilitated with single crowns and 8 with splinted crowns. The implant survival rate was 100%, with a mean follow-up of 33.8 ± 10.6 months after surgery. There were 6 (2 non-splinted) cases of prosthetic screw loosening, resulting in a prosthetic complications rate of 27.3%, with an average follow-up of 28.6 ± 10.86 months after prosthesis installation.

Conclusions Within the study limitations, it can be concluded that 4-mm implants show high survival but also relevant occurrence of prosthetic complications.