Microbiological evaluation of the efficacy of chlorhexidine in a sustained-release device for dentine sterilization.

The aim of this in-vitro study was to evaluate the effect of chlorhexidine in solution and in a sustained-release device as an intracanal medication. Hollow cylindrical dentine specimens prepared from bovine incisors were incubated with Streptococcus faecalis for a period of 3 weeks. The intracanal medicaments tested were 0.2% chlorhexidine gluconate solution (CH), chlorhexidine in a sustained-release device (1.2 mg) (SBD), camphorated paramonochlorophenol (CMCP), and a control (no medication). Each medicament was introduced into the lumen of one dentine specimen and incubated for 5 min, 24 h, 48 h or 7 days at 37 degrees C. The bacteriological samples were taken by shaving the dentine inside the lumen with dental burs ranging in size from ISO 023-033. The dentine powder was collected in test-tubes containing growth medium and incubated for 24 h. The optical density of the medium was recorded by means of a spectrophotometer at a wavelength of 540 nm. There was a statistically significant difference between the control group and all the medicaments tested.