Clinical, microbiological and histological factors associated with successful guided tissue regeneration in human mandibular Class II buccal furcation defects
The aim of this study was to look at factors, clinical, microbiological, and histological, that would affect the success of GTR in mandibular Class II buccal furcation defects. Researchers took 30 subjects with an age range of 22 to 66 years, all of whom had Class II furcas on first and second molars with no radiographically detectable interproximal bony defects. Their study design consisted of Phase I therapy of oral hygiene and supragingival scaling. They randomized into group A, which received subgingival scaling and root planing, and group B, which received subgingival scaling and root planing except for the last tooth. One month after the hygiene phase they took the following baseline measurements: PI, GI, PD, and PAL, using a stent and subgingival plaque sampling. They also took intrasurgical measurements and followed the protocol for e-PTFE membrane placement. After six weeks they harvested the membrane, fixed it in formaldehyde, and examined it histologically. The subjects were given OHI and prophylaxis biweekly for the first three months and then every month for one year. They reentered the sites after 12 months and retook measurements.
The results showed a mean pocket depth reduction of 50% from 5.43 to 2.82. The horizontal attachment level showed a gain of 2.59 mm and the vertical attachment level showed a gain of 0.95 mm. They showed 90% resolution of Class II defects. Groups A and B had similar healing results. The researchers looked at the factors that affected the healing and saw that age was not a significant factor. Preoperative pocket depth showed that the greater the pocket depth, the greater the potential for new bone formation in the furcation. Patients that demonstrated better oral hygiene consistently showed a better regenerative response. A. actinomycetemcomitans was a factor that negatively affected bone regeneration. The subjects who did not harbor the A.a. had significantly better bone regeneration than patients who did. Retrieved membrane that had connective tissue cells as opposed to bacterial plaque or epithelial remnants was associated with better regenerative results. In summary, the variables that affect guided tissue regeneration are initial probing depths, oral hygiene, presence or absence of A.a., and presence or absence of connective tissue cells on the retrieved membranes. [M.C.R.]
Machtei E.E., M. Cho, R. Dunford, J. Norderyd, J. Zambon, and R. Genco, J Periodont, 65:154,1994