title: Evaluation of effectiveness of various irrigating solutions on removal of calcium hydroxide mixed with 2% chlorhexidine gel and detection of orange-brown precipitate after removal.
abstract: BACKGROUND
  The aims of the present study were to evaluate the effect of various irrigating solutions on the removal of calcium hydroxide mixed with 2% chlorhexidine gel from an artificial groove created in a root canal and the generation of orange-brown precipitate in the remaining calcium hydroxide mixed with 2% chlorhexidine gel after irrigation with the various irrigating solutions.
  
  
  METHODS
  The root canals of 48 mandibular premolars were prepared using ProTaper Universal Rotary instruments (Dentsply Maillefer, Ballaigues, Switzerland) up to size F4. The roots were split longitudinally, and a standardized groove was prepared in the apical part of 1 segment. The root halves were reassembled, and calcium hydroxide mixed with 2% chlorhexidine gel medicament was placed into the grooves. The roots were randomly divided into 4 experimental groups specified by the irrigation solution used: 1% NaOCl, 17% EDTA, 7% maleic acid, and 10% citric acid (n = 12). The amount of remaining medicament was evaluated under a stereomicroscope using a 4-grade scoring system. After irrigation, the specimens were also evaluated for the presence/absence of orange-brown precipitate. The effects of the different irrigation solutions on medicament removal were statistically evaluated using the Kruskal-Wallis and Mann-Whitney U tests with Bonferroni correction at a 95% confidence level (P = .0083).
  
  
  RESULTS
  Solutions of 7% maleic acid and 10% citric acid were superior to solutions of 1% NaOCl and 17% EDTA in removing calcium hydroxide mixed with 2% chlorhexidine gel (P < .0083). There were no significant differences among the other groups (P > .0083). Orange-brown precipitate was observed in all specimens of the NaOCl group but in no specimens in the other groups.
  
  
  CONCLUSIONS
  Irrigation solutions of 7% maleic acid and 10% citric acid were more effective in the removal of calcium hydroxide mixed with 2% chlorhexidine gel than those of 1% NaOCl and 17% EDTA. Orange-brown precipitate was found in all specimens of the NaOCl-irrigated groups. However, the precipitate was not observed in specimens in the groups irrigated with 17% EDTA, 7% maleic acid, and 10% citric acid.
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Ataturk University, Erzurum, Turkey. Electronic address: hakan.arslan@atauni.edu.tr.
authors.forename: Hakan
authors.initials: H
authors.lastname: Arslan
authors.affiliation: Department of Endodontics, Faculty of Dentistry, İzmir Katip Çelebi University, İzmir, Turkey.
authors.forename: Tuba
authors.initials: T
authors.lastname: Gok
authors.affiliation: Department of Endodontics, Faculty of Dentistry, İzmir Katip Çelebi University, İzmir, Turkey.
authors.forename: Gokhan
authors.initials: G
authors.lastname: Saygili
authors.affiliation: Department of Pedodontics, Faculty of Dentistry, Katip Çelebi University, İzmir, Turkey.
authors.forename: Hülya
authors.initials: H
authors.lastname: Altintop
authors.affiliation: Department of Endodontics, Faculty of Dentistry, İzmir Katip Çelebi University, İzmir, Turkey.
authors.forename: Merve
authors.initials: M
authors.lastname: Akçay
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Ataturk University, Erzurum, Turkey.
authors.forename: Ismail Davut
authors.initials: ID
authors.lastname: Çapar
mesh_terms: D002126:Calcium Hydroxide / Q000737:chemistry*; D011232:Chemical Precipitation; D002710:Chlorhexidine / Q000737:chemistry*; D019343:Citric Acid / Q000737:chemistry; D004396:Coloring Agents / Q000737:chemistry; D019551:Dental Disinfectants / Q000737:chemistry*; D003786:Dental Pulp Cavity / Q000033:anatomy & histology; D004492:Edetic Acid / Q000737:chemistry; D005782:Gels; D006801:Humans; D008298:Maleates / Q000737:chemistry; D008422:Materials Testing; D011897:Random Allocation; D012388:Root Canal Irrigants / Q000737:chemistry*; D012973:Sodium Hypochlorite / Q000737:chemistry; D013499:Surface Properties; D019227:Tooth Apex / Q000033:anatomy & histology
chemical_list: D004396:Coloring Agents; D019551:Dental Disinfectants; D005782:Gels; D008298:Maleates; D012388:Root Canal Irrigants; D019343:Citric Acid; C030272:maleic acid; D004492:Edetic Acid; D012973:Sodium Hypochlorite; D002126:Calcium Hydroxide; D002710:Chlorhexidine
keywords: Calcium hydroxide; EDTA; citric acid; maleic acid; orange-brown precipitate; parachloroaniline; sodium hypochlorite