USE OF TOPICAL DESSICANT AGENT (HYBENX®) AS AN ADJUNCT TO ULTRASONIC DEBRIDEMENT IN THE INITIAL TREATMENT OF CHRONIC PERIODONTITIS: A CLINICAL AND MICROBIOLOGICAL PILOT STUDY IN HUMANS. Lombardo G., Signoretto C., Pardo A., *Flor C., Gelio V., Lubich S., Faccincani M. The aim of the study was to clinically and microbiologically evaluate if the ultrasonic debridement efficacy can be enhanced by the adjunctive topical administration of a liquid with hygroscopic properties (HYBENX ® Oral Tissue Decontaminant). RESULTS 16 patients completed this 3-month study. Compared with the control group the test group presented both at T2 and at T3 significantly greater reductions in Visible Plaque Index (VPI), Bleeding on Probing scores (BoP) (Fig. 1 e 2). No significant changes of PPD, GM and CAL between groups have been provided (Data not shown). As monotherapy, HBX reached the same bacterial load reduction as UD alone (Fig. 3 e 4). Compared to UD, HBX associated to UD, resulted immediately after treatment in a statistically significant greater bacterial load reductions, and the difference was still present after 6 weeks in the anaerobic bacterial load. At 3 months, after the repeated treatment, both groups presented significant differences in anaerobic bacterial load compared with the baseline (Fig. 5) MATERIALS AND METHOD Twenty patients presenting moderate to severe chronic periodontitis were enrolled in a randomized 3-month, split- mouth, single-blind, prospective study. At baseline control and test sides were treated with supra and subgingival ultrasonic debridement (UD) in adjunction, for the test group, of a locally delivered desiccant liquid (HYBENX®). Treatments were repeated after 6 weeks. Clinical (VPI, BoP, GI, PPD, CAL, GM) and microbiological anaerobic (ANAER) and aerobic (AER) bacterial loads were assessed at baseline before treatment. Samples were collected in the same session in test group immediately after the topical administration (T1b) to assess whether the topical agent had some effectiveness if administered alone, and then samples were repeated in both group after UD treatment (T1c). Microbiological sampling and Clinical measurements were repeated after 6 weeks (T2) and after 3 months (T3). CONCLUSIONS The short term results of this 3-month study demonstrated that greater inflammatory signs and anaerobic bacterial load reductions may be provided from the topical association of a desiccant liquid (HybenX ® ) to the ultrasonic instrumentation. Under the limitations of this study design, no statistical differences were demonstrated on PPD, CAL and GM. HBX as monotherapy Fig. 3 e 4: Comparison between the aerobic and anaerobic total bacterial loads reductions (log10) assessed after the mere HBX subgingival administration in the test group (A) and after the UD administration in the control group (B) T1a: First treatment session, at baseline, before treatments T1b: First treatment session, immediately after HBX administration and before UD, in the test group T1c: First treatment session, immediately after UD administration in the control group Fig. 1 e 2: Percentage of sites presenting plaque accumulation(VPII) and presenting bleeding after probing (BoP) at the various examination intervals: statistically significant difference between groups. Fig. 5: Aerobic and anaerobic total bacterial loads (log10) in subgingival biofilm at different time intervals for control and test groups. T1a: First treatment session, at baseline, before treatments; T1c: First treatment session, immediately after UD administration; T2: Second treatment session, after 6 weeks from baseline, (ie 6 weeks from the first treatment );T3: Third treatment session, after 3 months from baseline, (ie 6 weeks from the repeated treatment) UD-HBX: UD-HBX treated sites UD: UD treated sites (A) (B) UD as monotherapy