title: Interaction between chlorhexidine-impregnated gutta-percha points and several chlorine-containing endodontic irrigating solutions.
abstract: OBJECTIVE
  To evaluate if the immersion of chlorhexidine-impregnated gutta-percha points in chlorine-containing endodontic irrigants causes colour changes and precipitate formation.
  
  
  METHODS
  Eighty-one size 25 chlorhexidine medicated (Activ Points, Roeko, Langenau, Germany) and 27 size 25 standard gutta-percha points (Roeko) were immersed in microtubes, containing the following solutions: 0.5 and 5.25% NaOCl or Aquatine (Optident, Ilkley, UK). The samples were visually assessed, by two independent observers, at regular intervals over 3 weeks, to detect colour changes and precipitate formation. A score system was used to grade the precipitate intensity. To compare the number of days required for a precipitate to form mean and standard differences were calculated; the means between the groups were compared using a one-way analysis of variance test. Mean intensity scores were calculated and compared between groups using Kruskal-Wallis procedure followed by the Mann-Whitney test.
  
  
  RESULTS
  The groups containing 5.25% NaOCl started to produce a visible precipitate after fourteen days (16.48 ± 0.98) for the Activ points; this process was first noticed with the standard gutta-percha group on day 17 (18.33 ± 1.22 days), with a statistically significant difference (P = 0.002). When looking at the intensity scores from day 17 onwards, these two groups differed statistically, with a greater amount for the AP group (P < 0.001). No other test group presented with changes.
  
  
  CONCLUSIONS
  The placement of impregnated gutta-percha points, in 5.25% NaOCl for a 2-week period, caused the formation of a precipitate in the experimental conditions of this study.
authors: Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, RS, Brazil. grossifede@yahoo.com
authors: G
authors: G
authors: Rossi-Fedele
authors: E J
authors: EJ
authors: Doğramacı
authors: L
authors: L
authors: Steier
authors: J A P
authors: JA
authors: de Figueiredo
mesh_terms: D000891:Anti-Infective Agents, Local / Q000737:chemistry*; D011232:Chemical Precipitation; D002710:Chlorhexidine / Q000737:chemistry*; D002713:Chlorine / Q000737:chemistry*; D003116:Color; D019551:Dental Disinfectants / Q000737:chemistry; D006171:Gutta-Percha / Q000737:chemistry*; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry; D006997:Hypochlorous Acid / Q000737:chemistry; D008422:Materials Testing; D012387:Root Canal Filling Materials / Q000737:chemistry*; D012388:Root Canal Irrigants / Q000737:chemistry*; D012973:Sodium Hypochlorite / Q000737:chemistry; D013997:Time Factors
chemical_list: D000891:Anti-Infective Agents, Local; D019551:Dental Disinfectants; D012387:Root Canal Filling Materials; D012388:Root Canal Irrigants; C118085:superoxidized water; D002713:Chlorine; D006997:Hypochlorous Acid; D006171:Gutta-Percha; D006861:Hydrogen Peroxide; D012973:Sodium Hypochlorite; D002710:Chlorhexidine