Enhanced root planing and systemic metronidazole administration improve clinical and microbiological outcomes in a two-step treatment procedure

Background: Recently we described a non-surgical two-step treatment concept, in which we distinguished between a first scaling and root planing step (SRP) and an additional second enhanced root planing step (ERP). Until now it is difficult to determine how often a root surface should be instrumented during ERP. Methods: The aim of the present study was to investigate the outcomes after different root planing intensities during ERP in 37 patients with aggressive periodontitis after SRP. During ERP a full-mouth root planing was performed. The patients were randomly assigned to one of two root planing regimens (group 1, N = 12 and group 2, N = 11), based on number of curet strokes per root surface (instrumentation frequency, IF) and probing depth. Group 1: PD 1 to 3.5 mm, 4 IF (for group 2, 8 IF); PD 4 to 6 mm, 8 IF (group 2, 14 IF); PD 6.5 to 9 mm, 12 IF (group 2, 20 IF); and PD > 9 mm, 16 IF (group 2, 24 IF). Group 3 patients (controls; N = 14) received only the initial SRP. All three groups received the same adjunctive systemic antibiotic treatment. Results: In all groups, the results showed statistically significant differences in PD and clinical attachment level (CAL) after 6 and 24 months compared to baseline data. Compared with the controls, a significant reduction in PD was observed in groups 1 and 2. The reduction in mean PD was distinctly greater in group 2 (higher IF). Furthermore, Porphyromonas gingivalis (Pg) and Actinobacillus actinomycetemcomitans (Aa) were completely suppressed in group 2 after 24 months. Conclusions: The present results show that the extent of root planing has a distinct influence on treatment outcomes. Patients treated with the highest instrumentation frequency showed the best long-term results.