Long-Term Stability After Regenerative Treatment of Infrabony Defects: A Retrospective Case Series

This study aims to evaluate long-term stability of attachment achieved in infrabony defects (IBDs) by regenerative treatment.

All patients who had received regenerative treatment for at least one IBD between 2004 and 2010 were screened for this retrospective case series. If complete examinations (plaque/gingival index, probing depth [PD], vertical clinical attachment level [CAL-V]) were available for patients at baseline and 12 months after surgery, they were invited for reexamination 60 ± 12 months after surgery. Reexamination involved testing for interleukin (IL)-1 polymorphism and counting number of supportive periodontal treatment (SPT) visits. Forty-one patients (24 males and 17 females; age, median: 62.0 years, lower/upper quartile: 49.8/68.3 years; six smokers, and 9 IL-1 positive) were included for analysis, each contributing one IBD.

Regenerative therapy resulted in significant attachment gain after 1 (median: -3 mm, lower/upper quartile: -1.5/-4 mm; P <0.001) and 5 (median: -3 mm, lower/upper quartile: -1.9/4.5 mm; P <0.001) years. The study failed to detect median change of CAL-V from 1 to 5 years after surgery (median: 0 mm; lower/upper quartile: -1/1.5 mm; P = 0.84). Multiple regression analysis identified that number of SPT visits is correlated with CAL-V gain from 1 to 5 years after surgery. IL-1 polymorphism and percentage of sites with PD >6 mm at 5-year reexamination are correlated with CAL-V loss from 1 to 5 years after surgery.

CAL-V achieved by regenerative therapy in IBDs may have retained stability over 5 years. Frequent SPT is associated with stability. IL-1 polymorphism and generalized reinfection are associated with less stability.