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Azerbaycan Saytlari

 »  Home  »  Endodontic Articles 9  »  Inflammatory response to different endodontic irrigating solutions
Inflammatory response to different endodontic irrigating solutions
Introduction - Materials and methods.

M. Tanomaru Filho, M. R. Leonardo, L. A. B. Silva, F. F. Anibal & L. H. Faccioli.
Department of Endodontics, School of Dentistry of Araraquara, University of the State of Sao Paulo, Araraquara, SP, Brazil.
Department of Clinical Pediatrics, School of Dentistry of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, SP, Brazil.
School of Medicine of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, SP, Brazil.
School of Pharmaceutical Science, University of Sao Paulo, Ribeirao Preto, SP, Brazil.

During the biomechanical preparation of infected teeth with no pulp vitality, special attention must be given to the elimination of bacteria and their subproducts from the root-canal system. These factors play an important role in the development and maintenance of periapical lesions and thus, the success of root-canal treatment (Leonardo et al.1994, Sjogren et al. 1997). Therefore, biomechanical preparation must be supplemented by irrigating solutions that have an antibacterial effect (Bystrom & Sundqvist 1983, Jeansonne &White1994, Leonardo et al.1995, Leonardo 1998).
The most popular irrigating solution is sodium hypochlorite because of its physico-chemical and antibacterial properties. It is recommended for treatment of teeth without pulp vitality, particularly at high concentrations, because these have greater antibacterial effect than diluted solutions (Yesilsoy et al. 1995, Ayhan et al. 1999). However, more concentrated solutions can irritate periapical and apical tissues (Spangberg 1973). Since irrigating solutions can contact periapical tissue during biomechanical preparation, biocompatibility with these tissues is important. Thus, irrigating solutions with antibacterial activity and biocompatibility, such as chlorhexidine, have been proposed as an alternative for treatment of teeth with infected root canals. The antibacterial effect and long-acting nature of 2% chlorhexidine digluconate (Delany et al.1982, Ohara et al. 1993, Jeansonne &White1994, White et al.1997, Komorowski et al. 2000) has led researchers to recommend its use in root-canal treatment (Jeansonne & White 1994, White et al.1997, Leonardo et al.1999).The biocompatibility of chlorhexidine has been reported (Southard et al. 1989); however, its biological response when associated with sodium hypochlorite has not been studied.
The objective of this study was to analyze the inflammatory response of 0.5% sodium hypochlorite and 2% chlorhexidine injected into the peritoneal cavity of mice.

Materials and methods.
All animals were housed in facilities approved by the UNESP, Brazil. The use of animals for this research was approved by the local Ethical Committee for Animal Research and NIH guidelines stated in the ‘Principles of Laboratory Animal Care’ (NIH guidelines 1985) were followed.

Cellular migration to the peritoneal cavity.
Sixty male Swiss mice (6-8 weeks old, 15-20 g body weight) were randomly divided into three groups of 20 mice each. Each group received a 0.3-mL intra-peritoneal injection:
  1. phosphate buffered saline (control, PBS:7.2g sodium chloride,1.38 g of monobasic sodium phosphate and 6.96 g of dibasic potassium phosphate);
  2. 0.5% sodium hypochlorite;
  3. 2% chlorhexidine digluconate.
The solutions were prepared at the Chemistry Institute of Araraquara, UNESP, Brazil.
Five animals from each group were sacrificed at 4, 24, 48 h or 7 days (168 h) after intra-peritoneal injection with an anaesthetic overdose. Four milliliters of PBS/ 0.05% sodium citrate was injected for intra-peritoneal washing. An aliquot was separated and centrifuged, and the supernatant was stored at _20 8C for cell counting. Total and differential cell count Twenty-microlitre aliquots of peritoneal liquid were diluted and homogenized in 400 mL of Turk solution (15 mL glacial acetic acid, 0.2m L genetian violet, 500 mL distilled and deionized water) and then placed in Neubauer chamber (Improved Neubauer, Levy Hemacytometer, Hausser Scientific, Gaithersburg, MD, USA). Total inflammatory cell count was performed with an optic microscope (Zeiss, Jena, Germany, 120x).
Twenty microlitres of intra-peritoneal washing were centrifuged (Cytospin 3, Shandon Inc., Pittsburgh, PA, USA), at 900 _ g, for 3 min. Smear slides were dried at room temperature and were stained with Rosenfeld stain (Faccioli et al. 1990) for differential inflammatory cell, polymorphonuclear neutrophil and mononuclear cell counts (macrophage and lymphocyte). Neutrophil and mononuclear cell counts were performed with an optic microscope (Jenamed 2, Zeiss) with an immersion lens (1000x).

Protein leakage.
The supernatant of the peritoneal cavity stored at _20 8C was used for evaluation of protein leakage, as a parameter of oedema. Protein concentration was determined using Comassie stain (Pierce, Rockford, IL, USA), according the instructions of the manufacturer.

Statistical analysis.
The inflammatory cell migration was analyzed by the Kruskal-Wallis test. The groups were also compared using the Miller test.