Chlorhexidine Inhibits the Proteolytic Activity of Root and Coronal Carious Dentin in vitro.
ABSTRACT The purpose of this study was to evaluate the effect of chlorhexidine on the proteolytic activity of carious coronal and root dentin collected from patients. Sound dentin from freshly extracted human teeth was used as a control. Dentin fragments were mixed with a synthetic substrate for proteolytic enzymes (N-benzoyl-DL-arginine-naphthylamide--BANA) and the suspensions mixed with either 0.12% chlorhexidine digluconate or distilled water. These mixtures were incubated for 18 h at 37 degrees C, color was developed by the addition of 0.1% Fast Garnet and their optical density was recorded spectrophotometrically. BANA hydrolysis measured by the optical density of incubated specimens was detected in all tested groups, but was significantly higher for carious than for sound dentin (p < 0.05). The proteolytic activity was reduced for carious coronal and root dentin by chlorhexidine (p < 0.05; 50 and 30%, respectively). Chlorhexidine also reduced the proteolytic activity in sound root dentin (p < 0.05; 20%). Conversely, changes in the proteolytic activity of sound coronal dentin were not observed in the presence of chlorhexidine. The reduction in proteolytic activity by chlorhexidine was significantly higher in carious coronal dentin than in carious root dentin (p < 0.05). In conclusion, part of the effect of chlorhexidine in controlling caries progression in humans may be due to a decrease in the proteolytic activity of carious coronal and root dentin. Because of the prolonged incubation time in the present study, similar results may be obtained clinically with prolonged dentin exposure to chlorhexidine, e.g. chlorhexidine-containing varnishes.
- SourceAvailable from: Luciana Mendonça da Silva[Show abstract] [Hide abstract]
ABSTRACT: AIM: To assess the immediate influence of dentine bonding systems (DBS) associated with 2% chlorhexidine digluconate (CHX) on glass-fibre post-bond strength to root dentine, in terms of coronal, middle and apical thirds. METHODOLOGY: Sixty bovine roots were root filled and randomly assigned to 1 of 6 groups (n = 10): SBMP (3-step etch-and-rinse system, Scotchbond Multi-Purpose), SB (2-step etch-and-rinse system, Single Bond 2), SE (2-step self-etching system, Clearfil SE Bond) and SBMP-CHX, SB-CHX and SE-CHX, respectively, associated with CHX. For all groups, a glass-fibre post was luted with a dual-cure resin cement, RelyX ARC. After 7-day storage, specimens were subjected to the push-out test. Failure modes were analysed under optical microscopy (40x). Bond strength values were statistically analysed by two-way anova and Bonferroni tests (P < 0.05). RESULTS: The effect of DBS was significant (P < 0.05), and SE reached higher bond strength in comparison with the other DBS tested. CHX association did not show improvement with any DBS (P > 0.05); rather, it negatively affected SE, which was detected for all thirds. There was no difference between thirds (P > 0.05), except for the SE-CHX, which presented lower values for the apical third (P < 0.05). Adhesive cement/dentine adhesive failure was predominant for all groups. CHX did not influence the failure mode for any DBS (P > 0.05). CONCLUSIONS: The performance of the dentine bonding systems was material dependent. CHX did not improve immediate bond strength; however, CHX negatively affected the bond strength of the self-etching system, especially in the third apical.International Endodontic Journal 01/2013; DOI:10.1111/iej.12070
- Dental Materials 03/2012; 28(6):687-694.
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ABSTRACT: This study evaluated catechin and chlorhexidine release from copolymers based on bis-GMA diluted with TEGDMA (R1), propoxylated bis-GMA-CH(3)bis-GMA (R2) or fluorinated bis-GMA-CF(3)bis-GMA (R3). Mechanical properties, degree of conversion, water sorption and solubility were also tested. Experimental comonomers (R1, R2, R3) were prepared combining bis-GMA with the diluents (70/30 mol%). Each comonomer had either catechin or chlorhexidine incorporated in the following ratios: 0, 0.2, 1.0, 2.0 wt%. The degree of conversion (%DC) of resins was evaluated by FT-IR spectrophotometry (n=3). Flexural strength and elastic modulus were tested on a universal testing machine at a crosshead speed of 0.5mm/min (n=6). Resin disks (7 mm in diameter × 2 mm high) were immersed in deionized water and mass changes recorded daily. Spectral measurements were made to follow any changes in optical densities of deionized water in order to examine catechin and chlorhexidine release rates (n=6). After a 28-day period, water sorption and solubility were calculated using appropriate equations (n=6). Data within the tests were evaluated by one- and three-way ANOVA and Tukey-Kramer's test (α=0.05). Except for R1 with 2.0% drug none of the groups had changes in degree of conversion and water sorption. Solubility increased with increased drug ratios. Changes in flexural strength and elastic modulus were shown to be variable and material-dependent. All resins presented a ∼24 h burst of drug release. Release rates were drug-ratio dependent and significantly higher for chlorhexidine than for catechin. Monomer type, %DC, drug ratio and type lead to different interactions between resins and chlorhexidine/catechin drug particles. It should be possible to develop different resins based on clinical needs.Dental materials: official publication of the Academy of Dental Materials 03/2012; 28(6):687-94. DOI:10.1016/j.dental.2012.03.003