The effect of scaling and root planing on the clinical and microbiologicalparameters of periodontal diseases: 12-month results

Background/aims: Previously, we reported that SRP resulted in a decrease in mean pocket depth and attachment level and reduced prevalence and levels o f Bacteroides forsythus, Porphyromonas gingivalis, and Treponema denticola at 3 and 6 months post-SRP in 57 subjects with adult periodontitis. 32 of t he 57 subjects were monitored at 9 and 12 months. Thus, the purpose of the present investigation was to evaluate the microbial and clinical effects of SRP in 32 (mean age 48+/-11) subjects over a 12-month period. Method: Clinical assessments of plaque, gingival redness, suppuration, blee ding on probing, pocket depth and attachment level were made prior to SRP a nd at 3, 6, 9, and 12 months post-therapy. Subgingival plaque samples were taken at each visit and analyzed using the checkerboard DNA-DNA hybridizati on technique for the presence and levels of 40 subgingival species. Each su bject also received maintenance scaling at each of the subsequent monitorin g visits. Differences in clinical parameters and prevalence and levels of b acterial species were analyzed pre- and post-therapy using the Wilcoxon sig ned ranks test. The Quade test for related samples was used for analysis of multiple visits. Results: Mean pocket depth (mm+/-SEM) decreased from 3.2+/-0.3 at baseline to 2.9+/-0.3 at 12 months (p<0.01). Mean attachment level showed significan t reduction at 6 months, but did not diminish further. Bleeding on probing and plaque were significantly reduced at 12 months (p<0.001, p<0.05, respec tively). P. gingivalis, B. forsythus and T. denticola decreased in prevalen ce and levels up to the 6-month visit and remained at these lower levels at 9 and 12 months. Significant increases in levels and prevalence were noted at 12 months for Actinomyces naeslundii genospecies 2, Actinomyces odontol yticus, Fusobacterium nucleatum as polymorphum, Streptococcus mitis, Capnoc ytophaga sp, and Veillonella parvula. Conclusions: The data suggest that the maintenance phase of therapy may be essential in consolidating clinical and microbiological improvements achiev ed as a result of initial therapy.