Bone density of class II furcation lesions treated by guided tissue regeneration - A follow-up study by digital analysis of superimposable radiographs

12 buccal or lingual class II furcation lesions were selected in the lower molars of 7 patients after treatment by routine scaling. In each of the 7 patients, 1 lesion was treated by guided tissue regeneration (GTR) with expanded polytetrafluoroethylene membranes, while 5 neighbouring molars underwent conventional flap operations. The index of gingival inflammation, the plaque index, the depths of the pockets, the horizontal and vertical attachment levels were measured before and 6 months, 1 year and 2 years after surgery. Standardized reproducible radiographs were taken before treatment, post-operatively (at the time of membrane removal for the GTR treated sites), at 6 months, 1 year and 2 years after treatment. The density of bone was quantified in several areas by using high-resolution digital analysis. With the exception of the higher gain in horizontal attachment observed in the GTR treated furcations, the improvement of clinical parameters was similar in all sites during the 2 years of follow-up. The radiographical analysis showed no statistically significant changes neither in the GTR nor in the conventionnally treated lesions over this period of time, even when they were compared to untreated bone control areas. However, in this study limited to 7 patients, the interdental bone next to the GTR treated furcations showed significant signs of remodeling.