A prospective study on implants installed with flapless-guided surgery using the all-on-four concept in the mandible

Aim Clinical data are scarce on flapless-guided surgery in the mandible using the all-on-four concept. In addition, limited documentation exists on the latter under immediate loading conditions with a pre-fabricated implant bridge. The aim was to provide detailed documentation focusing on clinical and radiographic outcome and complications. Material and methods Sixteen systemically healthy non-smoking patients (10 women, 6 men, average age 59years) with sufficient bone volume in the mandible were operated via flapless-guided surgery using the all-on-four concept. Clinical and radiographic data and complications were registered at 3, 6 and 12months. Results The overall implant survival rate was 90% with a trend for higher failure of short implants (P=0.098). The mean bone level after 12months of function was 0.83mm with a maximum of 1.07mm. Technical complications were common (15/16 patients). These mainly related to a misfit between the pre-fabricated prosthesis and abutment(s) (13/16 patients). Conclusion If immediate loading of implants is pursued fabrication of the implant bridge should be based on actual impression of the implants at the time of surgery and not on their virtual position.