Guided tissue regeneration with bioabsorbable barriers. II. Long-term results in infrabony defects

The aim of this 5-year randomized controlled clinical trial was to evaluate the long-term results after guided tissue regeneration (GTR) therapy of infrabony defects using two bioabsorbable barriers.

Fifteen pairs of contralateral infrabony defects in 15 patients with moderate to severe periodontitis were treated. Each patient received one polydioxanon (test: T) and one polylactide acetyltributyl citrate (control: C) barrier by random assignment. At baseline, 12, and 60 +/- 3 months after surgery clinical parameters and standardized radiographs were obtained. Vertical bone levels (PBL-V) were measured during surgery and 60 +/- 3 months later by transgingival bone sounding.

Thirteen patients were available for the 60-month examinations. Twelve and 60 +/- 3 months after GTR, statistically significant (P< or =0.001) vertical attachment (CAL-V) gain was found in both groups (T12: 3.5 +/- 1.5 mm; T60: 2.2 +/- 1.8 mm; C12: 4.0 +/- 0.9 mm; C60: 2.4 +/- 1.0 mm). However, from 12 to 60 months after therapy both groups experienced significant CAL-V loss (P<0.05): two defects in the test group and three in the control group had CAL-V loss >2 mm compared to the 12-month reexamination. Twelve and 60 +/- 3 months after surgery, statistically significant (P<0.05) radiographic bony fill was found in both groups (T12: 1.2 +/- 1.3 mm; T60: 1.5 +/- 2.2 mm; C12: 0.9 +/- 1.4 mm; C60: 1.0 +/- 1.6 mm). Further, 60 months after surgery significant (P<0.05) PBL-V gain was found in both groups (test: 1.8 +/- 2.3 mm; control: 2.2 +/- 1.8 mm). The study failed to show statistically significant differences between test and control regarding CAL-V and PBL-V gain 60 months after surgery.

CAL-V gain achieved after GTR therapy in infrabony defects using both bioabsorbable barriers was stable after 5 years in 21 of 26 defects (81%).