The Clinical Prognosis of Single Cantilevered Restoration: the Retrospective Study
Materials and methods :
This study targeted 34 patients (20 males, 14 females)who were treated with a single cantilevered restoration (mesial direction or distal direction) combined with implant installation from May 2004 to December 2013. Radiographic examinations were taken after the implant installation, 1-year after the restoration, and at every OPD (outpatient department) follow-ups during an average of 4 years, and the status of the implant restorations were evaluated at each time. The prognosis was analyzed by clinical finding and the amount of crestal bone loss around the implant, and Pearson analysis was performed to see a correlation between the length of cantilever and the crestal bone loss around the implants using the SPSS (version 17.0)
Results
Total of 37 implants were included in this study and a half was placed in maxilla while the other implants were placed in mandible. The length of the implants was over 3mm and they were named “single cantilevered restoration”. The length of cantilevers ranged from 3.01 to 5.99
All implants survived during the average of 4 years of observation period while 7 implants showed complications. The most frequent complication was peri-implantitis with symptoms such as swelling and bleeding. Five implants showed this complication. Other complications were mechanical complications, screw loosening. and fracture. The incidence rate(5.41%) of these complications was considerable because it resembled the conventional rate of mechanical complications in other study.
1 year after the restoration, there was an average of 0.04±0.13mm crestal bone loss around the implant. At the final follow-up day, average of 0.18±0.50mm crestal bone was lost, which was a lower value than the regular crestal bone loss (first 1-year of restoration : 0.9mm / 0.1mm per every year )
There was a little correlation between the length of cantilever and the amount of crestal bone loss around implants at both 1-year after the restoration(correlation value 0.152, p-value 0.371, sample size 37 ) and the final follow-up day(correlation value 0.143, p-value 0.399, sample size 37 ).
Conclusion
Although single cantilevered restoration shorter than 6mm does not induce crestal bone loss around the implant, several complications such as peri-implantitis and mechanical complications could still remain