Clinical, microbiological and immunological effects of antiseptics in periodontal treatment

Abstract: Periodontal diseases are characterized by high prevalence in many populations and the chronic and progressive course of the disease. A fundamental stage of treatment is mechanical debridement of the tooth surface. During debridement antimicrobial agents may be applied as adjunctive intrasulcular irrigants. There is lack of consensus as to the optimal type of antimicrobial therapy in treatment of periodontal disease. A new antiseptic solution, containing polyhexa- methylene guanidine phosphate (PHMG-P) as the active ingredient, has recently been marketed as an adjunctive irrigant in periodontal treatment. Since there is no sufficient history of oral application of this antiseptic, few scientific is evidence available to support its efficiency. The aim of the thesis was to investigate the effects of antiseptics on bacteria and human cells and to evaluate the efficacy of adjunctive (PHMG-P) irrigation of periodontal pockets during scaling and root planing (SRP). Clinical, microbiological and immunological parameters were evaluated. In the initial in vitro study (Paper I), the anti-microbial activity of antiseptics was investigated. Using a quantitative suspension method, PHMG-P was com- pared with chlorhexidine (CHX) on standard quality control bacterial strains of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans, the periopathogens Porphyromonas gingivalis, Aggregatibacter actino- mycetemcomitans and also Streptococcus mutans, and Lactobacillus acidophilus, microorganisms implicated in dental caries. In Paper II the cytotoxic and immune- modulatory effects of the antiseptics on human gingival fibroblasts were determined. In Paper III the clinical efficacy of intrasulcular irrigation with PHMG-P and CHX as adjunctives to periodontal debridement in patients with severe chronic peri- odontitis was investigated. Finally, Paper IV evaluated the impact of the antiseptics on microflora and cytokine profiles in periodontal pockets undergoing treatment. Papers I and II showed that PHMG-P had anti-microbial activity and cytotoxic- ity and expressed anti-inflammatory properties. In Paper III it was shown that adjunctive PHMG-P irrigation improved the short-term outcome of SRP, but had no significant long-term effect on the mean pocket depth. Paper IV showed that although antiseptic treatment caused changes in biomarkers and bacterial counts, no differences in these parameters were observed between the treatment groups at any of the follow-up examinations. Conclusion: In the in vitro studies, PHMG-P showed pronounced antimicrobial activity. The primary response to periodontal treatment was attributable to the mechanical debridement. The adjunctive antiseptic irrigants, applied in accord- ance with the study protocol, had only limited effects.