Prognosis of implants placed in combination with bone spreading

Objectives: Bone spreading using hand osteotomes has been described as a technique to allow implant placement in cases of reduced widths of the alveolar ridge. Objective of this prospective study was to investigate the short-term outcome of implants placed in the maxilla in combination with bone spreading.

Methods: A total of 126 implants were placed in the maxilla with reduced bone width using osteotomes to spread the alveolar bone. After a 2.2mm pilot drill the further preparation was performed with standardized hand osteotomes. Sixty-three maxillary implants inserted without bone spreading or bone augmentation served as controls. A total of 83 implants were placed in the anterior region and 106 in the posterior maxilla, including 153 Straumann implants (SLA) and 36 Replace select implants (Nobel Biocare). Implant failures were recorded after a minimal observation period of 7 months (mean: 1.48 years; maximum: 4.81). Survival analyses were used to estimate survival curves for the implants and to isolate risk factors for implant failures and complications.

Results: A total of 6 complications were recorded (experimental group: 2; control group: 4). Three implants failed because of missing osseous integration during the first 3 months after implant placement. Other severe complications were peri-implant inflammations (n=2) occurring between 1 and 2 years after surgery, and one exposure of the rough implant surface. After 2 years, Kaplan-Meier curves demonstrate a probability of survival without complications of 94.5% for the experimental group and 92% for the control group. The tendency to higher complication rates in the control group was not significant (p=0.076). Using Cox regression analysis the factors bone spreading location, implant system or closed versus open healing showed no effect on the complication rate (0.074<p<0.932). Conclusions: Implant placement combined with bone spreading technique using hand osteotomes does not increase short-term complications compared to conventionally placed implants.