title: Influence of chlorhexidine on the degree of conversion and E-modulus of experimental adhesive blends.
abstract: OBJECTIVE
  This study examined the effect of chlorhexidine (CHX) content on degree of conversion (DC) and E-modulus of experimental adhesive blends. The hypothesis tested was that increasing concentrations of CHX result in decreased DC and E-modulus in relation to adhesive hydrophilicity.
  
  
  METHODS
  Experimental adhesive blends with increasing hydrophilicity R2 (70% bisGMA, 28.75% TEGDMA); R3 (70% BisGMA, 28.75% HEMA); R4 (40% BisGMA, 30% TCDM, 28.75% TEGDMA); R5 (40% BisGMA, 30% BisMP, 28.75% HEMA) and different CHX concentrations (1 and 5%) were analyzed. 5% CHX could not be dissolved in R2. A differential scanning calorimeter was used to measure the DC of resin blends. Photopolymerized disks of the experimental comonomer mixtures (n=10/gp) were used to measure the E-modulus of each specimen using a biaxial flexure test. Data were analyzed with two-way ANOVA (resin type and CHX concentration) and Tukey's post hoc test.
  
  
  RESULTS
  The addition of 1% CHX did not significantly alter the DC of R2 and R3. Significant decrease in R3 DC values was observed when 5% CHX was added. CHX significantly increased the DC of R4 and R5. 1% CHX reduced the E-modulus of all resins (p<0.05) except for R2, in which the E-modulus was significantly increased (p<0.05). 5% CHX significantly reduced the E-modulus of resins R3 to R5 (p<0.05).
  
  
  CONCLUSIONS
  In conclusion, increasing concentrations of CHX dissolved in resin blends had little adverse effect on DC but decreased the E-modulus 27-48% compared to controls. Solvation of CHX in ethanol prior to incorporation of CHX into R2 may permit higher CHX concentrations without lower polymer stiffness.
authors: Department of Biomedicine, University of Trieste, Trieste, Italy.
authors: M
authors: M
authors: Cadenaro
authors: D H
authors: DH
authors: Pashley
authors: G
authors: G
authors: Marchesi
authors: M
authors: M
authors: Carrilho
authors: F
authors: F
authors: Antoniolli
authors: A
authors: A
authors: Mazzoni
authors: F R
authors: FR
authors: Tay
authors: R
authors: R
authors: Di Lenarda
authors: L
authors: L
authors: Breschi
mesh_terms: D000891:Anti-Infective Agents, Local / Q000737:chemistry*; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002152:Calorimetry, Differential Scanning; D002710:Chlorhexidine / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry; D055119:Elastic Modulus; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D018583:Pliability; D011092:Polyethylene Glycols / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry*; D012995:Solubility; D017155:Wettability
chemical_list: D000891:Anti-Infective Agents, Local; D003188:Composite Resins; D008689:Methacrylates; D011108:Polymers; D011109:Polymethacrylic Acids; D019279:Resin Cements; C020946:triethylene glycol dimethacrylate; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; C005044:hydroxyethyl methacrylate; D002710:Chlorhexidine