title: Antimicrobial Activity and Physicochemical Properties of Calcium Hydroxide Pastes Used as Intracanal Medication.
abstract: The aim of the present study was to evaluate the pH, calcium release, solubility, and antimicrobial action against biofilms of calcium hydroxide + saline solution, Calen (SS White Artigos Dentários Ltd, Rio de Janeiro, Brazil) (CH/P), Calen camphorated paramonochlorophenol (CMCP) (CH/CMPC), and calcium hydroxide + chlorhexidine (CH/CHX) pastes.
  
  
  
  The pH of the pastes was determined with a calibrated pH meter placed in direct contact with each paste. The root canals of acrylic teeth (N = 10) were ﬁlled with the previously mentioned intracanal dressings and immersed in ultrapure water to measure hydroxyl (pH meter) and calcium ion release (atomic absorption spectrophotometer) at time intervals of 3, 7, 15, and 30 days. To assess solubility, the root canals of acrylic teeth (N = 10) were filled with the previously mentioned pastes and scanned by micro-computed tomographic imaging before (initial) and after 7, 15, and 30 days of immersion in ultrapure water. The solubility of each specimen was the difference between the initial and final volume scanning. For antimicrobial analysis, monospecies and dual-species biofilms were in vitro induced on dentin blocks (N = 20). Afterward, they were treated with the pastes for 7 days. Live/dead dye and a confocal microscope were used to measure the percentage of living cells. Data were statistically compared (P < .05).
  
  
  
  The highest OH-ion release values were found in 3 and 30 days. Ca2+releases were greater in CH/CMCP. CH/P and CH/CMCP showed a higher percentage of volume loss values. CH/CHX presented the greatest antimicrobial action.
  
  
  
  CH/P and CH/CMPC showed higher solubility values in the period analyzed. Seven days of contact may be insufficient for calcium hydroxide + saline solution, CH/P, and CH/CMCP pastes to kill bacterial cells in the biofilms studied. Chlorhexidine added to CH favored greater effectiveness against the previously mentioned bacterial biofilms.
authors: Department of Restorative Dentistry, Dental Materials and Endodontics, Bauru Dental School, University of São Paulo, Bauru, São Paulo, Brazil. Electronic address: rafaelazancan@yahoo.com.br.
authors: Rafaela Fernandes
authors: RF
authors: Zancan
authors: Department of Restorative Dentistry, Dental Materials and Endodontics, Bauru Dental School, University of São Paulo, Bauru, São Paulo, Brazil.
authors: Rodrigo Ricci
authors: RR
authors: Vivan
authors: Integrated Research Center, Bauru Dental School, University of São Paulo, Bauru, São Paulo, Brazil.
authors: Marcelo Ribeiro
authors: MR
authors: Milanda Lopes
authors: Pro-Rectory of Research and Graduate Studies, University of Sagrado Coração, Bauru, São Paulo, Brazil.
authors: Paulo Henrique
authors: PH
authors: Weckwerth
authors: Department of Restorative Dentistry, Dental Materials and Endodontics, Bauru Dental School, University of São Paulo, Bauru, São Paulo, Brazil.
authors: Flaviana Bombarda
authors: FB
authors: de Andrade
authors: Department of Surgery, Stomatology, Pathology and Radiology, Bauru Dental School, University of São Paulo, Bauru, São Paulo, Brazil.
authors: José Burgos
authors: JB
authors: Ponce
authors: Department of Restorative Dentistry, Dental Materials and Endodontics, Bauru Dental School, University of São Paulo, Bauru, São Paulo, Brazil.
authors: Marco Antonio Hungaro
authors: MA
authors: Duarte
mesh_terms: D000180:Acrylic Resins; D000890:Anti-Infective Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects / Q000254:growth & development; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D002118:Calcium / Q000737:chemistry; D002126:Calcium Hydroxide / Q000494:pharmacology*; D055598:Chemical Phenomena; D002710:Chlorhexidine / Q000494:pharmacology; D002733:Chlorophenols / Q000494:pharmacology; D003786:Dental Pulp Cavity; D004338:Drug Combinations; D006863:Hydrogen-Ion Concentration; D006878:Hydroxides; D007180:Incisor; D018613:Microscopy, Confocal; D009824:Ointments / Q000494:pharmacology*; D012387:Root Canal Filling Materials / Q000494:pharmacology; D012388:Root Canal Irrigants / Q000494:pharmacology*; D012965:Sodium Chloride / Q000494:pharmacology; D012995:Solubility; D014092:Tooth Root / Q000187:drug effects; D014867:Water; D055114:X-Ray Microtomography
chemical_list: D000180:Acrylic Resins; D000890:Anti-Infective Agents; D002733:Chlorophenols; D004338:Drug Combinations; D006878:Hydroxides; D009824:Ointments; D012387:Root Canal Filling Materials; D012388:Root Canal Irrigants; C420643:calen; D014867:Water; C029107:4-chlorophenol; D012965:Sodium Chloride; C031356:hydroxide ion; D002126:Calcium Hydroxide; D002710:Chlorhexidine; D002118:Calcium
keywords: Antimicrobial action; biofilms; calcium hydroxide paste; intracanal medication; physicochemical properties