A comparison of chlorhexidine release rate from three polymeric controlled release drug prototypes

Complete debridement and thorough disinfection of infected root canals are considered mandatory for the success of root canal treatment. However, canal preparation and irrigation are not always effective in eliminating total microflora from the root canal system. Traditionally, calcium hydroxide has proven to be an excellent intracanal medicament for infected root canals. However, it is known to be less effective against the therapy-resistant flora such like Enterococcus facecalis, Actinomyces and Candida that are frequently isolated in persistent root canals. This is because of dilution of calcium hydroxide as time passes or dentin buffering effects. Therefore, alternative medicaments should be explored that would maximize microbial eradication when used as intracanal disinfection. Intracanal disinfection of infected root canal is one of important treatment procedure. This in vitro study aimed to evaluate whether the surface polymers of controlled release drug (CRD) can effectively control the release rate of chlorhexidine for root canal disinfection. Four CRD prototypes were prepared: Group A (n=12); The core device (absorbent paper point) was loaded with 40% CHX solution as control. Group B (n=12); same as group A, but the device was coated with chitosan. Group C (n=12); same as group A and then coated three times with 5% PMMA. Group D (n=12); same as group A and then coated three times with 3% PLGA. All CRD prototypes were soaked in 3 mL distilled water for experimental periods and the concentrations of released CHX from each CRD prototype were determined using a UV spectrophotometer. Results showed that release rate of CHX were the greatest in the non-coated group (control group), followed by the chitosan-coated group, the PLGA-coated group, and the PMMA-coated group (P < 0.05). This data indicate that surface polymers can control the release rate of CHX from the CRD prototypes. [J Kor Acad Cons Dent 29(6):548-552, 2004]