Clinical effects of scaling and root planing on untreated teeth

Objective: The aim of this report is to examine whether scaling and root planing (SRP) in one area of the mouth may affect periodontal improvement in untreated areas in the same patient, possibly through systemic effects of treatment. Material and Methods: Twenty patients diagnosed with generalized aggressive periodontitis were randomized into treatment (n = 11) and no treatment (n = 9) groups. Within the treatment group, three quadrants were treated by SRP at week 0, 3, 12, and 24, while a single experimental quadrant remained untreated throughout the study. The outcome for all teeth was assessed using clinical parameters, subtraction radiography, and pathogenic bacteria levels in the subgingival flora over the 24-week study period. Results: Compared with sites in no treatment patients, the treated sites in the treated patients showed a 1 mm decrease in probing depth (PD) (p < 0.01) and a 0.5 mm increase in bone height (p < 0.01) by 24 weeks. In untreated sites within treated subjects, however, PDs tended to improve (p = 0.09) but at a reduced rate compared with treated sites. The levels of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Tannerella forsythensis (Bacteroides forsythus) remained unchanged in untreated sites while levels of Prevetolla intermedia and Treponema denticola tended to decrease as compared with controls but did not reach significance. Conclusions: This study indicates that untreated sites in treated periodontitis patients show a trend towards clinical improvement and exhibit reductions in some but not all periodontopathic bacterial species tested.