The aim of this 5-year retrospective clinical study was to evaluate the failure rates of implants installed in the anterior and posterior region of maxilla and mandible.
Method: One thousand and twenty patients (809 men and 211 women, aged between 19 and 75 years) received a total of 2130 dental implants. The implants were installed in the maxilla (n=1057) anterior (n=551) and posterior region (n=506); and in the mandible (n=1073), anterior (n=167) and posterior region (n=906) too. All surgical and prosthetic procedures were performed by six experienced dentists that followed strict clinical protocols. All subjects were examined by pre-operative computed tomography and the surgery was planned according to a computer-assisted surgical protocol to define the width and length of each implant. A two stage technique was used in the majority of the cases. The healing time was 6 months in the maxilla and 4 months in the mandible. Second-stage surgery was performed to install the healing abutments. The final impressions were taken with pick-up transfers, custom impression trays and polyether. After careful occlusal adjustment, the definitive restorations were placed.
Result:
The failure rate was 3.5% for maxilla and 2.5 % for mandible, however there was no significant difference in implant failure rate between maxilla and mandible (p=0.22). Most of the implants were placed in the posterior quadrant of the mandible. Comparing failure rates of implants placed in anterior maxilla versus posterior maxilla (p=0.92), and anterior mandible versus posterior mandible (p=0.48), there was no significant difference. There was also no difference when the posterior maxilla was compared with the posterior mandible (p=0.23), or when comparing the anterior maxilla with the anterior mandible (p=0.88).
Conclusion: The results obtained in this retrospective study revealed that the implants installed had high survival rates and the location did not influence the failure.