Periodontal regeneration of human infrabony defects. II. Re-entry procedures and bone measures.

This paper evaluates the osseous healing response of 40 infrabony defects treated with guided tissue regeneration. The selected sites presented with deep periodontal lesions with a 1-, 2-, and 3-wall combination infrabony component of 6.1 +/- 2.5 mm. Baseline intrasurgical clinical measurements were compared with intrasurgical clinical measurements obtained at the 1 year surgical re-entry. A significant regeneration of bone of 4.3 +/- 2.5 mm was observed, along with a 0.4 +/- 1.9 mm resorption of the alveolar bone crest, which resulted in a 4.7 mm reduction of the original infrabony defect. Almost 90% of the sites showed a bone gain of 2 mm or more, while no site lost supporting bone; 73 +/- 31.2% of the original defect was filled with bone. The 3- and 2-wall components were filled 95 +/- 6.2% and 82 +/- 18.7% of their original depth, respectively; however, the 1-wall component was filled only 39 +/- 62.4%. It is concluded that treatment of infrabony defects according to the principles of guided tissue regeneration and a strict plaque control regimen resulted in clinically significant and highly predictable bone regeneration.