NEW MICROBIOLOGICA, 36, 289-302, 2013 Comparison of the antibacterial activity of an ozonated oil with chlorhexidine digluconate and povidone-iodine. A disk diffusion test Marco Montevecchi 1 , Antonio Dorigo 1 , Monica Cricca 2 , Luigi Checchi 1 1 Department of Periodontology and Implantology, School of Dentistry, Alma Mater Studiorum, University of Bologna, Bologna, Italy; 2 Department of Experimental, Diagnostic and Specialty Medicine-DIMES, Alma Mater Studiorum, University of Bologna, Bologna, Italy INTRODUCTION Bacterial colonization of dental surfaces is con- sidered to be the primary causative factor of pe- riodontitis (Socransky et al., 1998; Flemming, 1999). The World Workshop of Periodontology defined Aggregatibacter actinomycetemcomitans, Porphy- romonas gingivalis and Tannerella forsythia as pe- riodontal pathogens (Consensus Report., 1996). This designation is based on strong evidence sup- Corresponding author Marco Montevecchi Department of Periodontology and Implantology School of Dentistry Via San Vitale, 59 - 40120 Bologna, Italy E-mail: m.montevecchi@unibo.it porting an etiologic role of periodontal diseases for these species. Other bacteria, classified in chromatic microbial complexes on the basis of their interaction, have also been related to peri- odontal diseases (Socransky et al., 1998). The periodontal impairment mostly results from an intricate sequence of host immune reactions to pathogens (Honda et al., 2006). This process, conditioned by multiple factors, progressively in- volves the apical portions of the tooth support, inducing a gradual loss of periodontal attachment and alveolar bone, with tooth loss as the final out- come (Schwartz et al., 1997). A similar pattern has been recognized for peri-implantitis (Lindhe et al., 1992; Berglundh et al., 2004). The primary goal of periodontal therapy is to erad- icate the periodontal pathogens within tooth and dental implants. Removal of subgingival biofilm Ozonated oils are antiseptics obtained from the chemical reaction between ozone and unsaturated fatty acids of veg- etable oils. The aim of this study was to investigate the antimicrobial effectiveness of a commercially available ozonat- ed oil (O 3 -Oil), in comparison with 0.2% chlorhexidine digluconate (CHX) and 10% povidone-iodine (PVP-I) through a disk diffusion test. For each antiseptic a series of two-fold dilutions was made, obtaining seven dilutions: 1:2, 1:4, 1:8, 1:16, 1:32, 1:64 and 1:128. The undiluted antiseptics and the seven dilutions were tested against two freeze-dried bacterial strains: Staphylococcus aureus (Sa) and Porphyromonas gingivalis (Pg). O 3 -Oil showed significantly greater diameters of growth inhibition (p<0.01) than CHX and PVP-I in all dilutions for both tested strains. CHX lost any an- tibacterial efficacy when diluted more than 1:32. At the highest dilution, the diameters of growth inhibition against Sa were 20.67±0.58 mm and 15.33±0.58 mm, for O 3 -Oil and PVP-I, respectively. At the same dilution, the diameters of growth inhibition against Pg were: 19.00 mm for O 3 -Oil and 13.67±0.58 mm for PVP-I. The promising results ob- tained for the O 3 -Oil, against the opportunistic Sa, and Pg, one of the main periodontal pathogens, suggest its poten- tial applicability for periodontal treatment. Further preclinical and clinical investigations are warranted. KEY WORDS: Ozonated oil, Antibacterial activity, Staphylococcus aureus, Porphyromonas gingivalis, Periodontal dis- ease, Peri-implantitis. SUMMARY Received February 11, 2013 Accepted May 26, 2013