title: Mechanical properties and modeling of drug release from chlorhexidine-containing etch-and-rinse adhesives.
abstract: OBJECTIVE
  To evaluate the effects of chlorhexidine (CHX) addition in different concentrations into simplified etch-and-rinse adhesives on the ultimate tensile strength (UTS), water sorption (WS), solubility (SO) and the rate of CHX release over time.
  
  
  METHODS
  We added CHX diacetate to Ambar [AM] (FGM) and XP Bond [XP] (Dentsply) in concentrations of 0, 0.01, 0.05, 0.1 and 0.2 wt%. For UTS (n=10 for each group), adhesive specimens were constructed in an hourglass shape metallic matrix with cross-sectional area of 0.8 mm(2). Half of specimens were tested after 24 h and the other half after 28 days of water storage in tension of 0.5 mm/min. For WS and SO (n=10 for each group), adhesive discs (5.8 mm×1.0 mm) were prepared into a mold. After desiccation, we weighed and stored the cured adhesive specimens in distilled water for evaluation of the WS, SO and the cumulative release of CHX over a 28-day period. For CHX release (n=10 for each group), spectrophotometric measurements of storage solution were performed to examine the release kinetics of CHX. We subjected data from each test to ANOVA and Tukey' test (α=0.05).
  
  
  RESULTS
  XP Bond adhesive showed significantly more WS and SO and lower UTS than Ambar. In general, the addition of CHX did not alter WS, SO and UTS of the adhesives. XP showed a higher CHX release than AM (p<0.05) in all concentrations and the final amount of CHX release was directly proportional to the initial CHX concentration added to the adhesives. After 28 days of water storage, approximately 20% of CHX was released from XP and 8.0-12.0% from AM.
  
  
  CONCLUSIONS
  Addition of CHX to commercial adhesive is a feasible method to provide a controlled release of CHX over time without jeopardizing WS, SO and UTS of the adhesives.
  
  
  CONCLUSIONS
  Manufacturers should consider adding CHX to commercial adhesives to provide a controlled release of CHX over time.
authors: Department of Restorative Dentistry, Center of Higher Education of Campos Gerais, Ponta Grossa, Brazil.
authors: Rodrigo
authors: R
authors: Stanislawczuk
authors: Department of Restorative Dentistry, State University of Ponta Grossa, Ponta Grossa, Brazil.
authors: Alessandra
authors: A
authors: Reis
authors: School of Dentistry, State University of Ponta Grossa, Ponta Grossa, Brazil.
authors: Pamela
authors: P
authors: Malaquias
authors: School of Dentistry, State University of Ponta Grossa, Ponta Grossa, Brazil.
authors: Fabiane
authors: F
authors: Pereira
authors: Department of Pharmaceutical Sciences, State University of Ponta Grossa, Ponta Grossa, Brazil.
authors: Paulo Vitor
authors: PV
authors: Farago
authors: Department of Chemistry, State University of Santa Catarina, Joinville, Brazil.
authors: Marcia Margarete
authors: MM
authors: Meier
authors: Department of Restorative Dentistry, State University of Ponta Grossa, Ponta Grossa, Brazil. Electronic address: aloguercio@hotmail.com.
authors: Alessandro D
authors: AD
authors: Loguercio
mesh_terms: D000134:Acid Etching, Dental; D002710:Chlorhexidine / Q000737:chemistry*; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D065546:Drug Liberation; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry*; D012995:Solubility; D013718:Tensile Strength; D014867:Water / Q000737:chemistry
chemical_list: C000604625:Ambar; D017220:Dentin-Bonding Agents; D008689:Methacrylates; C532387:XP-Bond; D014867:Water; D002710:Chlorhexidine
keywords: Adhesives systems; Chlorhexidine; Chlorhexidine release; Solubility; Ultimate tensile strength; Water sorption