The aim of this investigation was to evaluate the effect of smoking on the outcome of periodontal therapy. The study consisted of 54 patients who participated in a 4-group parallel-arm clinical trial on the efficacy of three locally delivered antimicrobial systems as adjuncts to scaling and root planing in the treatment of sites with persistent pocketing after a course of scaling and root planing. These groups included scaling and root planing either alone (S) (n = 3), or in conjunction with the application of 25% tetracycline fibers (S&T) (n = 13), 2% minocycline gel (S&Mi) (n = 14), or 25% metronidazole gel (S&Me) (n = 14). In each patient four pockets > 5 mm with bleeding on probing (BOP) and/or suppuration were studied. The number of subjects who smoked was: 8 (61.5%) in the S&T group, 8 (57.1%) in the S&Mi group, 6 (42.9%) in the S&Me group, and 6 (46.2%) in the S group. The probing depth, attachment level and other clinical parameters were assessed at baseline and 6 weeks after treatments. The clinical results of this comparative study have been previously reported. Regardless of the type of treatment, the change in the probing depth (delta PD) and attachment gain (delta AL) were greater in non-smoker subjects than smoker subjects. delta PD was 1.14 mm versus 0.76 mm (P = 0.019), and delta AL was 0.52 mm versus 0.50 mm at (P = 0.845) for non-smokers and smokers respectively. The analysis of variance using the general linear model (GLM) was used for delta PD and delta AL and took into account the variations in the treatments, number of smoker subjects per group, and baseline probing depth. There was a significant interaction between the "smoking" and the "baseline PD." Further analysis using linear regression indicated that, while there was a significant relationship between the baseline PD and the delta PD or delta AL among the non-smokers, weak and insignificant relationship existed among the smoker subjects. Thus, smoking may have an important role in determining the prognosis of periodontal treatment, particularly in persistent and deep pockets.

Although all 3 locally applied antimicrobial systems seem to offer some benefit over scaling and root planing alone, a treatment regimen of scaling and root planing plus tetracycline fiber placement gave the greatest reduction in probing depth over the 6 months after treatment.

The aim of this study was to evaluate the efficacy of 3 commercially available periodontal systems for local delivery of antibiotics as adjuncts to scaling and root planing in treatment of sites with persistent periodontal lesions following a course of scaling and root planing. Fifty-four patients with 4 pockets > or = 5 mm and bleeding on probing and/or suppuration were randomized in 4 treatment groups including: scaling and root planing plus application of 25% tetracycline fiber (S + Tet) (13 patients), scaling and root planing plus application of 2% minocycline gel (S + Min) (14 patients), scaling and root planing plus application of 25% metronidazole gel (S + Met) (14 patients), and scaling and root planing alone (S) (13 patients). Clinical measurements were taken at baseline and 6 weeks after the end of treatment periods. All treatments were applied using the distributors' recommended protocols and resulted in significant improvement in probing depth, attachment level, bleeding on probing and the modified gingival index (MGI) scores. The improvements in clinical parameters were greater in all three adjunctive treatment groups than scaling and root planing alone. The mean probing depth reductions were: S + Tet = 1.35 mm, S + Met = 0.95 mm, S + Min = 0.87 mm and S = 0.60 mm. The probing depth reduction was significantly greater in the scaling plus tetracycline fiber group than the scaling and root planing alone group (P = 0.002). The difference between groups in improvement of attachment level or bleeding on probing was not significant Scaling plus tetracycline fiber treatment resulted in the greatest reduction in the MGI scores which was significantly greater than all other groups. While the frequency of sites with suppuration was markedly reduced following all treatments, it reached zero in the scaling plus tetracycline fiber group. No serious adverse effects were observed or reported for any treatment. While all three locally applied antimicrobial systems seem to offer some benefit over scaling and root planing alone, a treatment regimen of scaling and root planing plus tetracycline fiber replacement gave the greatest advantage in the treatment of persistent periodontal lesions at least during the 6-week period following treatment.

These findings call into question the value of performing repeated subgingival scaling at 3-month intervals for patients with persistent disease.

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