Evaluation of mandibular implant-supported fixed prosthesis retained by 3 dental implants, 1 straight and 2 angled: A retrospective clinical study

The minimum number of implants to support fixed complete dentures is still unclear. The purpose of this retrospective clinical study was to evaluate the survival rate of fixed complete dentures supported by 3 immediately loaded implants opposing maxillary complete dentures. A retrospective study of edentulous patients rehabilitated with complete dentures opposing mandibular metal-resin implant-supported fixed complete dentures supported by 3 immediately loaded implants was conducted in a 48-hour protocol. Fifty-one machined and 99 rough-surface implants were evaluated from 2.2 up to 8 years. Implant loss, peri-implant outcomes, and mechanical complications were assessed by considering the influence of age, sex, health status, smoking, excessive alcohol consumption, educational level, and socioeconomic status. The presence of comorbidities in relation to the implant surface or the cantilever lengths was also evaluated. Four machined and 6 rough-surface implants failed, a 6.7% failure rate. The cantilever length varied from 3.3 to 22.9 mm. Mechanical complications were abutment screw loosening (3.0%), prosthetic screw loosening (17%), screw fracture (1%), superstructure detachment and fractures (16%), metal framework fracture (2%), maxillary denture fractures (6%), and mandibular prosthesis loss (4%). Peri-implant mucositis was found in 27% of participants. The cumulative implant and mandibular prosthesis survival rates were 93.3% and 96%, respectively. None of the variables evaluated, including demographic data and health status, were found to influence clinical failures and/or mechanical complications. Mandibular fixed complete dentures supported by 3 implants can be considered a successful treatment with reduced costs compared with those of other fixed options for application in public health.