IADR Abstract Archives
INTRACANAL CHLORHEXIDINE SOLUTION AFFECTS BIOFILM on INITIAL NATURAL ROOT CARIES
Objectives: Currently, it is believed that initial natural root caries lesions (INRC) are underlined by dentine sclerosis that blocks the transport of materials from the pulp to the INRC, but this view is based on 2D analyzes. The aim of this in vitro study was to test a hypothesis that the composition of the endodontic material (irrigating solution with chlorhexidine) affects the cariogenicity of S.mutans biofilm formed on INRC surface in endodontically treated teeth.
Methods: Two studies (paired samples) were performed: (1) intracanal application of 2% chlorhexidine irrigating solution (n = 8; G1: INRC and G2: sound root surface); (2) intracanal application of solutions with different chlorhexidine concentrations (0.0%; 0.25%; 0.5%) (n = 24; INRC surfaces). Human anterior permanent single-rooted teeth with single root canal, presenting both sound (control) and INRC (experimental) surfaces, were selected (examiner Kappa of 0.97) with the aid of microCT, treated endodontically without canal obturation, sterilized with ethylene oxide, and then subjected for 5 days to Streptococcus mutans UA159 biofilm formation on the root surface (sound first, followed by INRC). After each biofilm formation period, CFUs, and both soluble (ECPs) and insoluble extracellular polysaccharides (ECPi) were quantified.
Results: Biofilms formed on INRC presented lower cariogenicity based on all parameters: CFU (p <0.0001; Hedge g = -5.3), ECPs (p <0.0001; Hedge g = -1.51;), and ECPi (p <0.0001; Hedge g = 1.80). Chlorhexidine concentration in the intracanal solution correlated negatively with CFU formed on INRC surface (p = 0.0068; R = -0.537). All lesions in study 1 presented a facilitated transport pathway between INRC surface and root canal, as revealed by microCT analysis using contrast solution.
Conclusions: Chlorhexidine irrigation solution applied in the root canal negatively affected S. mutans biofilm cariogenicity formed on the INRC surface due to a facilitated transport pathway between the root canal and INRC surface.
Methods: Two studies (paired samples) were performed: (1) intracanal application of 2% chlorhexidine irrigating solution (n = 8; G1: INRC and G2: sound root surface); (2) intracanal application of solutions with different chlorhexidine concentrations (0.0%; 0.25%; 0.5%) (n = 24; INRC surfaces). Human anterior permanent single-rooted teeth with single root canal, presenting both sound (control) and INRC (experimental) surfaces, were selected (examiner Kappa of 0.97) with the aid of microCT, treated endodontically without canal obturation, sterilized with ethylene oxide, and then subjected for 5 days to Streptococcus mutans UA159 biofilm formation on the root surface (sound first, followed by INRC). After each biofilm formation period, CFUs, and both soluble (ECPs) and insoluble extracellular polysaccharides (ECPi) were quantified.
Results: Biofilms formed on INRC presented lower cariogenicity based on all parameters: CFU (p <0.0001; Hedge g = -5.3), ECPs (p <0.0001; Hedge g = -1.51;), and ECPi (p <0.0001; Hedge g = 1.80). Chlorhexidine concentration in the intracanal solution correlated negatively with CFU formed on INRC surface (p = 0.0068; R = -0.537). All lesions in study 1 presented a facilitated transport pathway between INRC surface and root canal, as revealed by microCT analysis using contrast solution.
Conclusions: Chlorhexidine irrigation solution applied in the root canal negatively affected S. mutans biofilm cariogenicity formed on the INRC surface due to a facilitated transport pathway between the root canal and INRC surface.