title: Ultrastructural analysis of the root canal walls after simultaneous irrigation of different sodium hypochlorite concentration and 0.2% chlorhexidine gluconate.
abstract: To determine whether sodium hypochlorite (NaOCl) with 0.2% chlorhexidine gluconate (CHX) leads to colour change and precipitate formation, and to ultrastructurally analyse the dentine surface after simultaneous irrigation with 0.5% NaOCl and 0.2% CHX. Four tubes in which 5ml of different NaOCl concentrations and 5ml 0,2% CHX were placed, were observed every 15 minutes in the first two hours and after 7 days. Mixture solutions were centrifuged at 800 rpm/4 min. A precipitate is observed under light-microscopy. Thirty-five single-rooted teeth were instrumented using crown-down technique with irrigation: Positive control: distilled water, Negative control: 0,5% NaOCl+15% EDTA, Experimental group: identical to the negative control, then canals were treated with 0.5% NaOCl+0.2% CHX. The longitudinal root sections were observed under scanning-electron-microscopy. The amount of debris was assessed with 5/score-system, and the results were analysed using the Mann-Whitney U test (p < 0.001). Change in colour was noticed immediately after the merger and it did not change with time. Mixture solutions showed considerable turbidity, but precipitate was observed only after centrifugation. Statistical analysis showed a significant difference in the dentinal wall purity when comparing the cervical and middle root canal thirds between the experimental and negative control group. The difference was also observed between the cervical and middle thirds compared to the apical third of the root canal within these groups. Interaction between NaOCl and CHX, as well as the creation of precipitates, depends not only on the concentration of NaOCl, but also on the concentration of CHX.
authors.affiliation: Department of Restorative Dentistry and Endodontics, Clinic of Dentistry, Medical Faculty, University of Nis, Nis. jgasic@yahoo.com
authors.forename: Jovanka
authors.initials: J
authors.lastname: Gasic
authors.forename: Jelena
authors.initials: J
authors.lastname: Popovic
authors.forename: Slavoljub
authors.initials: S
authors.lastname: Zivković
authors.forename: Aleksandar
authors.initials: A
authors.lastname: Petrovic
authors.forename: Radomir
authors.initials: R
authors.lastname: Barac
authors.forename: Marija
authors.initials: M
authors.lastname: Nikolic
mesh_terms: D002498:Centrifugation; D011232:Chemical Precipitation; D002710:Chlorhexidine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D003116:Color; D003786:Dental Pulp Cavity / Q000187:drug effects / Q000648:ultrastructure*; D003804:Dentin / Q000737:chemistry / Q000187:drug effects*; D006801:Humans; D008855:Microscopy, Electron, Scanning; D009391:Nephelometry and Turbidimetry / Q000379:methods; D012388:Root Canal Irrigants / Q000737:chemistry / Q000494:pharmacology; D016369:Smear Layer; D012973:Sodium Hypochlorite / Q000737:chemistry / Q000494:pharmacology*; D018709:Statistics, Nonparametric; D014070:Tooth / Q000187:drug effects; D014075:Tooth Discoloration / Q000517:prevention & control
chemical_list: D012388:Root Canal Irrigants; D012973:Sodium Hypochlorite; C010882:chlorhexidine gluconate; D002710:Chlorhexidine