Single molar replacement in the lower jaw: a retrospective study

Objectives: The aim of this retrospective clinical trial was to evaluate the clinical performance of posterior implants in the lower jaw placed in a private practice. Methods: From November 1997 to December 2004, 80 implants (Ankylos, Friadent GmbH, Germany) were placed in 54 patients (31 male, 23 female) without simultaneous bone augmentation for the replacement of molars. All implants were restored with titanium abutments and metal-ceramic crowns (Golden Gate System, DeguDent GmbH, Germany) and luted with a temporary cement (Temp-Bond, KerrHawe, Germany). Restorations were evaluated every 6 months according to the following criteria: 1. Implant in situ, 2. Fracture of implant 3. Fracture of abutment or screw loosening, 3. Loss of retention for the superstructure, 4. Fracture of the veneering material. Results: Just one implant failed during the submerged healing period, two month after insertion (region 36). None of the remaining 79 implants failed after prosthetic treatment. The survival rate according to Kaplan-Meier was 98.8 % after 48 months, (mean clinical observation time: 29.5 ± 17.6 months). Prosthetic complications were observed in 4 restorations, summing up for a complication rate of 5.0 % (screw loosening: 0 %, loss of retention: 1.25 %, chipping of the veneering material: 3.75 %). All restorations could be maintained by recementation or intraoral polishing of the ceramics.Conclusions: Regarding the calculated survival rate for the implants and the low prosthetic complication rate of 5.0 %, after a mean observation period of 29.5 months, the use of osseointegrated implants for the replacement of posterior teeth in the lower jaw with temporarily cemented single tooth restorations seems to be a reliable treatment option for the use in a private practice.