Chlorhexidine Alone for Intracanal Medication

CHX alone has also been used and evaluated as an intracanal medication. This substance is a topical antiseptic solution that has been used worldwide since 1954 [131]. CHX is a cationic bis-biguanide that is insoluble in water and is formulated with either gluconic or acetic acid to form water-soluble

digluconate or diacetate salts. CHX is highly effective against several gram-positive and gram-nega- tive oral bacterial species as well as yeasts [114, 132–137]. In addition to its antimicrobial activity, CHX also presents substantivity in dentin [138– 140] and displays low irritation to living tissues [141, 142]. Because of these properties, CHX has emerged as a potential interappointment medication to be used alternatively to calcium hydroxide.

CHX is bacteriostatic at low concentrations and bactericidal at high concentrations [136]. The initial site of CHX action is the cytoplasmic membrane. CHX crosses the cell wall, presumably by passive diffusion, and subsequently attacks the cytoplasmic membrane. CHX binds to the negatively charged bacterial cell membrane and, at low concentrations, can affect its integrity, leading to rupture of the membrane (without lysis of the cell wall) and release of the cell constituents at a very low rate [143]. This effect is usually insufficient to induce cell death. However, at the high concentrations used under antiseptic/disinfectant conditions, CHX enters the cytoplasm via the damaged cytoplasmic membrane and promotes precipitation of cytoplasmic contents, particularly phosphated entities, with resulting cell death [144, 145].

While hydroxyapatite has little or no inhibitory effects on CHX [73], dentin matrix [146], bovine serum albumin [73], and necrotic tissue [72] have been shown to significantly inhibit its activity. CHX solutions may be stored at room temperature and a shelf-life of at least 1 year is expected, provided that packaging is adequate. Prolonged exposure to high temperature or light should be avoided.

Several in vitro studies have demonstrated that CHX is more effective than calcium hydroxide in eliminating E. faecalis or C. albicans from dentinal tubules [112, 127, 147–149]. There are not many clinical studies evaluating the effects of CHX alone as an intracanal medication. One study showed no significant difference in the incidence of postoperative pain in treatment or retreatment cases following chemomechanical preparation and intracanal medication with either CHX or a calcium hydroxide paste [150]. In terms of antimicrobial effectiveness, Vianna et al. [151] evaluated the antibacterial effects of a treatment protocol using chemomechanical preparation with 2 % CHX gel as auxiliary chemical substance followed by 7 days of intracanal dressing with calcium hydroxide, 2 % CHX gel, or calcium hydroxide/2 % CHX gel. The incidence of positive cultures after these medications was 62.5 %, 50 %, and 50 %, respectively, with no significant difference between them. Manzur et al. [71] reported an incidence of positive cultures of 18 % after calcium hydroxide

medication, 45.5 % after 2 % CHX, and 27 % after calcium hydroxide/CHX. They concluded that the antibacterial efficacy of the 3 medications was statistically comparable. Paquette et al. [32] evaluated the antibacterial efficacy of intracanal medication with 2 % CHX liquid and reported 68 % positive cultures. Malkhassian et al. [152] assessed the antibacterial efficacy of a final rinse with BioPure MTAD and intracanal medication with 2 % CHX gel and concluded that these approaches did not reduce bacterial counts beyond levels achieved by chemomechanical preparation with NaOCl. Teles et al. [153] observed that a 14-day intracanal medication with calcium hydroxide in inert vehicle performed significantly better than 2 % CHX gel as for reducing bacterial counts in teeth with apical periodontitis.

A study [154] evaluated the 2- to 4-year outcome of treatment using 2 % CHX liquid as the intracanal medication for 7–15 days. Findings revealed that 94 % of the teeth were healed and this finding did not differ significantly from that in a historical control using calcium hydroxide (90 %), suggesting a comparable outcome after medication with these two substances.

Other Intracanal Medicaments

In the past, several toxic substances were used as intracanal medicaments, including aldehydes (formocresol, tricresol formalin, glutaraldehyde) and phenolics (camphorated phenol or paramonochlorophenol, cresatin, eugenol). Most of them are too toxic to host tissues and some of them were ineffective in the clinical setting. Consequently, their use was abolished and no longer recommended.

Other Indications for Intracanal Medication

In addition to be indicated to improve disinfection in routine cases of primary or posttreatment apical periodontitis, an intracanal medication has also been recommended in the following occasional situations:

(a)To serve as a physicochemical barrier to protect against, or at least delay, bacterial contamination of the canal between appointments in uninfected cases where the endodontic treatment could not be completed in a single visit

(b)To act indirectly on inflammation by helping eliminate its primary cause, i.e., residual microorganisms in the apical canal in cases with persistent symptoms or exudation

(c)To help clean and disinfect areas untouched by instruments in teeth with aberrant internal anatomy, as, for instance, because of internal resorption or developmental anomalies. It has been shown that soft tissue pretreated with calcium hydroxide is more rapidly dissolved by NaOCl than when NaOCl is used alone [155]. It is recommended that a calcium hydroxide paste be packed into irregularities and then in the subsequent visit be removed by using endodontic instruments under copious irrigation with NaOCl and/or ultrasonic activation of NaOCl

(d)To help halt external root resorption processes, either by acting on the cause, i.e., bacteria infecting the root canal system, or by directly interfering with the resorptive process

(e)To eliminate infection and create an appropriate environment for apical closure or for regenerative approaches in immature teeth with necrotic pulps and open apexes

References

1.Langeland K. Tissue response to dental caries. Endod Dent Traumatol. 1987;3:149–71.

2. Ricucci D, Siqueira Jr JF. Fate of the tissue in lateral canals and apical ramifications in response to pathologic conditions and treatment procedures. J Endod. 2010;36:1–15.

3. Siqueira Jr JF. Treatment of endodontic infections. London: Quintessence Publishing; 2011.

4. Kakehashi S, Stanley HR, Fitzgerald RJ. The effects of surgical exposures of dental pulps in germ-free and conventional laboratory rats. Oral Surg Oral Med Oral Pathol. 1965;20:340–9.

5. Sundqvist G. Bacteriological studies of necrotic dental pulps [Odontological Dissertation no.7]. Umea: University of Umea; 1976.

6.Ricucci D, Siqueira Jr JF. Biofilms and apical periodontitis: study of prevalence and association with

clinical and histopathologic findings. J Endod. 2010;

8. Orstavik D. Root canal disinfection: a review of concepts and recent developments. Aust Endod J. 2003; 29:70–4.

9. Siqueira Jr JF. Strategies to treat infected root canals. J Calif Dent Assoc. 2001;29:825–37.

10. Haapasalo M, Endal U, Zandi H, Coil JM. Eradication of endodontic infection by instrumentation and irrigation solutions. Endod Topics. 2005;10:77–102.

11. Hoskinson SE, Ng YL, Hoskinson AE, Moles DR, Gulabivala K. A retrospective comparison of outcome of root canal treatment using two different protocols. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2002;93:705–15.

12. Cheung GS, Liu CS. A retrospective study of endodontic treatment outcome between nickel-titanium rotary and stainless steel hand filing techniques. J Endod. 2009;35:938–43.

13. Chugal NM, Clive JM, Spångberg LS. Endodontic infection: some biologic and treatment factors associated with outcome. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2003;96:81–90.

14. Chugal NM, Clive JM, Spångberg LS. A prognostic model for assessment of the outcome of endodontic treatment: effect of biologic and diagnostic variables. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2001;91:342–52.

15. de Chevigny C, Dao TT, Basrani BR, Marquis V, Farzaneh M, Abitbol S, Friedman S. Treatment outcome in endodontics: the Toronto study–phase 4: initial treatment. J Endod. 2008;34:258–63.

16. Orstavik D, Qvist V, Stoltze K. A multivariate analysis of the outcome of endodontic treatment. Eur J Oral Sci. 2004;112:224–30.

17. Sjögren U, Hagglund B, Sundqvist G, Wing K. Factors affecting the long-term results of endodontic treatment. J Endod. 1990;16:498–504.

18.Sjögren U, Figdor D, Persson S, Sundqvist G. Influence of infection at the time of root filling on the

outcome of endodontic treatment of teeth with apical periodontitis. Int Endod J. 1997;30:297–306.

19. Nair PNR. Light and electron microscopic studies of root canal flora and periapical lesions. J Endod. 1987;13:29–39.

20. Siqueira Jr JF, Rôças IN, Lopes HP. Patterns of microbial colonization in primary root canal infections. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2002;93:174–8.

21. Molven O, Olsen I, Kerekes K. Scanning electron microscopy of bacteria in the apical part of root canals in permanent teeth with periapical lesions. Endod Dent Traumatol. 1991;7:226–9.

22. Carr GB, Schwartz RS, Schaudinn C, Gorur A, Costerton JW. Ultrastructural examination of failed molar retreatment with secondary apical periodontitis: an examination of endodontic biofilms in an endodontic retreatment failure. J Endod. 2009;35:1303–9.

23. Schaudinn C, Carr G, Gorur A, Jaramillo D, Costerton JW, Webster P. Imaging of endodontic biofilms by combined microscopy (FISH/cLSM – SEM). J Microsc. 2009;235:124–7.

24. Nair PN, Henry S, Cano V, Vera J. Microbial status of apical root canal system of human mandibular first molars with primary apical periodontitis after “onevisit” endodontic treatment. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2005;99:231–52.

25. Ricucci D, Siqueira Jr JF. Apical actinomycosis as a continuum of intraradicular and extraradicular infection: case report and critical review on its involvement with treatment failure. J Endod. 2008;34: 1124–9.

26. Vera J, Siqueira Jr JF, Ricucci D, Loghin S, Fernandez N, Flores B, Cruz AG. Oneversus two-visit endodontic treatment of teeth with apical periodontitis: a histobacteriologic study. J Endod. 2012;38: 1040–52.

27. Tronstad L, Barnett F, Cervone F. Periapical bacterial plaque in teeth refractory to endodontic treatment. Endod Dent Traumatol. 1990;6:73–7.

28. Ferreira FB, Ferreira AL, Gomes BP, Souza-Filho FJ. Resolution of persistent periapical infection by endodontic surgery. Int Endod J. 2004;37:61–9.

29. Ricucci D, Martorano M, Bate AL, Pascon EA. Calculus-like deposit on the apical external root surface of teeth with post-treatment apical periodontitis: report of two cases. Int Endod J. 2005;38:262–71.

30. Peters LB, Wesselink PR, Buijs JF, van Winkelhoff AJ. Viable bacteria in root dentinal tubules of teeth with apical periodontitis. J Endod. 2001;27:76–81.

31. Vieira AR, Siqueira Jr JF, Ricucci D, Lopes WS. Dentinal tubule infection as the cause of recurrent disease and late endodontic treatment failure: a case report. J Endod. 2012;38:250–4.

32.Paquette L, Legner M, Fillery ED, Friedman S. Antibacterial efficacy of chlorhexidine gluconate intracanal medication in vivo. J Endod. 2007;33:788–95.

33.McGurkin-Smith R, Trope M, Caplan D, Sigurdsson A. Reduction of intracanal bacteria using GT rotary

instrumentation, 5.25% NaOCl, EDTA, and Ca(OH)2. J Endod. 2005;31:359–63.

34. Byström A, Sundqvist G. The antibacterial action of sodium hypochlorite and EDTA in 60 cases of endodontic therapy. Int Endod J. 1985;18:35–40.

35.Shuping GB, Ørstavik D, Sigurdsson A, Trope M. Reduction of intracanal bacteria using nickeltitanium rotary instrumentation and various medications. J Endod. 2000;26:751–5.

36.Siqueira Jr JF, Guimarães-Pinto T, Rôças IN. Effects of chemomechanical preparation with 2.5% sodium hypochlorite and intracanal medication with calcium hydroxide on cultivable bacteria in infected root canals. J Endod. 2007;33:800–5.

37.Siqueira Jr JF, Magalhães KM, Rôças IN. Bacterial reduction in infected root canals treated with 2.5% NaOCl as an irrigant and calcium hydroxide/camphorated paramonochlorophenol paste as an intracanal dressing. J Endod. 2007;33:667–72.

38.Siqueira Jr JF, Paiva SS, Rôças IN. Reduction in the cultivable bacterial populations in infected root canals by a chlorhexidine-based antimicrobial protocol. J Endod. 2007;33:541–7.

39. Siqueira Jr JF, Rôças IN, Paiva SS, Guimarães-Pinto T, Magalhães KM, Lima KC. Bacteriologic investigation of the effects of sodium hypochlorite and chlorhexidine during the endodontic treatment of teeth with apical periodontitis. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2007;104:122–30.

40.Rôças IN, Siqueira Jr JF. In vivo antimicrobial effects of endodontic treatment procedures as

assessed by molecular microbiologic techniques. J Endod. 2011;37:304–10.

41. Rôças IN, Siqueira Jr JF. Comparison of the in vivo antimicrobial effectiveness of sodium hypochlorite and chlorhexidine used as root canal irrigants: a molecular microbiology study. J Endod. 2011;37:143–50.

Ferreira DC, Curvelo JA, Soares RM, Rosado AS. Supplementing the antimicrobial effects of chemomechanical debridement with either passive ultrasonic irrigation or a final rinse with chlorhexidine: a clinical study. J Endod. 2012;38:1202–6.

44. Huffaker SK, Safavi K, Spångberg LS, Kaufman B. Influence of a passive sonic irrigation system on the elimination of bacteria from root canal systems: a clinical study. J Endod. 2010;36:1315–8.

45. Fabricius L, Dahlén G, Sundqvist G, Happonen RP, Möller AJR. Influence of residual bacteria on periapical tissue healing after chemomechanical treatment and root filling of experimentally infected monkey teeth. Eur J Oral Sci. 2006;114:278–85.

46. Waltimo T, Trope M, Haapasalo M, Ørstavik D. Clinical efficacy of treatment procedures in endodontic infection control and one year follow-up of periapical healing. J Endod. 2005;31:863–6.

47. Heling B, Shapira J. Roentgenologic and clinical evaluation of endodontically treated teeth with or without negative culture. Quintessence Int. 1978;11: 79–84.

48. Engström B, Hard AF, Segerstad L, Ramström G, Frostell G. Correlation of positive cultures with the prognosis for root canal treatment. Odontol Revy. 1964;15:257–70.

49. Sundqvist G, Figdor D, Persson S, Sjogren U. Microbiologic analysis of teeth with failed endodontic treatment and the outcome of conservative re-treatment. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 1998;85:86–93.

50. Siqueira Jr JF, Rôças IN. Optimising single-visit disinfection with supplementary approaches: a quest for predictability. Aust Endod J. 2011;37:92–8.

51. Siqueira Jr JF, Araujo MC, Garcia PF, Fraga RC, Dantas CJ. Histological evaluation of the effectiveness of five instrumentation techniques for cleaning the apical third of root canals. J Endod. 1997;23: 499–502.

52.Walton RE. Histologic evaluation of different methods of enlarging the pulp canal space. J Endod. 1976;2:304–11.

53. Peters OA, Schönenberger K, Laib A. Effects of four Ni-Ti preparation techniques on root canal geometry assessed by micro computed tomography. Int Endod J. 2001;34:221–30.

54. Siqueira Jr JF, Alves FR, Versiani MA, Rôças IN, Almeida BM, Neves MA, Sousa-Neto MD. Correlative bacteriologic and micro-computed tomographic analysis of mandibular molar mesial canals prepared by self-adjusting file, Reciproc, and Twisted File systems. J Endod. 2013;39:1044–50.

55. Paque F, Balmer M, Attin T, Peters OA. Preparation of oval-shaped root canals in mandibular molars using nickel-titanium rotary instruments: a microcomputed tomography study. J Endod. 2010;36: 703–7.

56.Hermann BW. Calciumhydroxyd als mittel zum behandeln und füllen von zahnwurzelkanälen. Würzburg, Med. Diss. 1920. 48p.

57.Fava LR, Saunders WP. Calcium hydroxide pastes:

classification and clinical indications. Int Endod

J. 1999;32:257–82.

58.Heithersay GS. Calcium hydroxide in the treatment of pulpless teeth with associated pathology. J Brit Endod Soc. 1975;8:74–92.

59.Siqueira Jr JF, Lopes HP. Mechanisms of antimicrobial activity of calcium hydroxide: a critical review. Int Endod J. 1999;32:361–9.

60.Byström A, Claesson R, Sundqvist G. The antibacterial effect of camphorated paramonochlorophenol, camphorated phenol and calcium hydroxide in the treatment of infected root canals. Endod Dent Traumatol. 1985;1:170–5.

61.Sharma P, Jha AB, Dubey RS, Pessarakli M. Reactive oxygen species, oxidative damage, and antioxidative defense mechanism in plants under stressful conditions. J Botany. 2012;Article ID 217037, doi:10.1155/2012.

62. Lobo V, Patil A, Phatak A, Chandra N. Free radicals, antioxidants and functional foods: impact on human health. Pharmacogn Rev. 2010;4:118–26.

63. Kumar V, Abbas AK, Fausto N, Aster JC. Robbins and Cotran pathologic basis of disease. 8th ed. Philadelphia: Saunders/Elsevier; 2010.

64.Freeman BA, Crapo JD. Biology of disease: free radicals and tissue injury. Lab Invest. 1982;47: 412–26.

65.Halliwell B, Gutteridge JMC. Free radicals in biology and medicine. 3rd ed. Oxford, UK: Oxford University Press; 1999.

66. Stuart KG, Miller CH, Brown Jr CE, Newton CW. The comparative antimicrobial effect of calcium hydroxide. Oral Surg Oral Med Oral Pathol. 1991;72:101–4.

67. Georgopoulou M, Kontakiotis E, Nakou M. In vitro evaluation of the effectiveness of calcium hydroxide and paramonochlorophenol on anaerobic bacteria from the root canal. Endod Dent Traumatol. 1993;9: 249–53.

68.Siqueira Jr JF, de Uzeda M. Influence of different vehicles on the antibacterial effects of calcium hydroxide. J Endod. 1998;24:663–5.

69. Sjögren U, Figdor D, Spångberg L, Sundqvist G. The antimicrobial effect of calcium hydroxide as a shortterm intracanal dressing. Int Endod J. 1991;24:119–25.

70. Peters LB, van Winkelhoff AJ, Buijs JF, Wesselink PR. Effects of instrumentation, irrigation and dressing with calcium hydroxide on infection in pulpless teeth with periapical bone lesions. Int Endod

J. 2002;35:13–21.

71.Manzur A, Gonzalez AM, Pozos A, Silva-Herzog D, Friedman S. Bacterial quantification in teeth with apical periodontitis related to instrumentation and different intracanal medications: a randomized clinical trial. J Endod. 2007;33:114–8.

72.Oliveira JC, Alves FR, Uzeda M, Rocas IN, Siqueira Jr JF. Influence of serum and necrotic soft tissue on the antimicrobial effects of intracanal medicaments. Braz Dent J. 2010;21:295–300.

73.Portenier I, Haapasalo H, Rye A, Waltimo T, Ørstavik D, Haapasalo M. Inactivation of root canal medicaments by dentine, hydroxylapatite and bovine serum albumin. Int Endod J. 2001;34:184–8.

74. Haapasalo M, Qian W, Portenier I, Waltimo T. Effects of dentin on the antimicrobial properties of endodontic medicaments. J Endod. 2007;33: 917–25.

75. Ricucci D, Siqueira Jr JF. Anatomic and microbiologic challenges to achieving success with endodontic treatment: a case report. J Endod. 2008;34:1249–54.

76. Love RM. Invasion of dentinal tubules by root canal bacteria. Endod Topics. 2004;9:52–65.

77. Barnett F. The role of endodontics in the treatment of luxated permanent teeth. Dent Traumatol. 2002;18: 47–56.

78. Estrela C, Pimenta FC, Ito IY, Bammann LL. Antimicrobial evaluation of calcium hydroxide in infected dentinal tubules. J Endod. 1999;25:416–8.

79. Haapasalo M, Ørstavik D. In vitro infection and disinfection of dentinal tubules. J Dent Res. 1987;66: 1375–9.

80. Heling I, Steinberg D, Kenig S, Gavrilovich I, Sela MN, Friedman M. Efficacy of a sustained-release device containing chlorhexidine and Ca(OH)2 in preventing secondary infection of dentinal tubules. Int Endod J. 1992;25:20–4.

81. Orstavik D, Haapasalo M. Disinfection by endodontic irrigants and dressings of experimentally infected dentinal tubules. Endod Dent Traumatol. 1990;6: 142–9.

82. Safavi KE, Spångberg LS, Langeland K. Root canal dentinal tubule disinfection. J Endod. 1990;16: 207–10.

83.Siqueira Jr JF, de Uzeda M. Disinfection by calcium hydroxide pastes of dentinal tubules infected with two obligate and one facultative anaerobic bacteria. J Endod. 1996;22:674–6.

84. Sukawat C, Srisuwan T. A comparison of the antimicrobial efficacy of three calcium hydroxide formulations on human dentin infected with Enterococcus faecalis. J Endod. 2002;28:102–4.

85. Siqueira JF Jr, Machado de Oliveira JC, Magalhães FAC, Lopes HP. Efeitos do hidróxido de cálcio associado a diferentes veículos sobre dentina contaminada. Revista Brasileira de Odontologia. 2001;58:44–7.

86. Weiger R, de Lucena J, Decker HE, Lost C. Vitality status of microorganisms in infected human root dentine. Int Endod J. 2002;35:166–71.

87.Tronstad L, Andreasen JO, Hasselgren G, Kristerson L, Riis I. pH changes in dental tissues after root canal filling with calcium hydroxide. J Endod. 1981;7:17–21.

88. Padan E, Zilberstein D, Schuldiner S. pH homeostasis in bacteria. Biochim Biophys Acta. 1981;650: 151–66.

89.Atlas RM. Principles of microbiology. 2nd ed. Dubuque, USA: WCB Publishers; 1997.

90.Waltimo TM, Siren EK, Ørstavik D, Haapasalo MP. Susceptibility of oral Candida species to calcium hydroxide in vitro. Int Endod J. 1999;32:94–8.

91.Evans M, Davies JK, Sundqvist G, Figdor D. Mechanisms involved in the resistance of Enterococcus faecalis to calcium hydroxide. Int

Endod J. 2002;35:221–8.

92. Pinheiro ET, Gomes BP, Ferraz CC, Sousa EL, Teixeira FB, Souza-Filho FJ. Microorganisms from canals of root-filled teeth with periapical lesions. Int Endod J. 2003;36:1–11.

93. Rôças IN, Jung IY, Lee CY, Siqueira Jr JF. Polymerase chain reaction identification of microorganisms in previously root-filled teeth in a South Korean population. J Endod. 2004;30:504–8.

94. Rôças IN, Siqueira Jr JF, Santos KR. Association of Enterococcus faecalis with different forms of periradicular diseases. J Endod. 2004;30:315–20.

95. Siqueira Jr JF, Rôças IN. Polymerase chain reactionbased analysis of microorganisms associated with failed endodontic treatment. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2004;97:85–94.

96. Rôças IN, Siqueira Jr JF. Characterization of microbiota of root canal-treated teeth with posttreatment disease. J Clin Microbiol. 2012;50:1721–4.

97. Gomes BP, Pinheiro ET, Jacinto RC, Zaia AA, Ferraz CC, Souza-Filho FJ. Microbial analysis of canals of root-filled teeth with periapical lesions using polymerase chain reaction. J Endod. 2008;34: 537–40.

98. Rietschel ET, Kirikae T, Schade U, Mamat U, Schmidt G, Loppnow H, Ulmer AJ, Zahringer U, Seydel U, Padova FD, Schreier M, Brade H. Bacterial

endotoxin: molecular relationships of structure to activity and function. FASEB J. 1994;8:217–25.

99.Rietschel ET, Brade H. Bacterial endotoxins. Sci Am. 1992;267:26–33.

100.Safavi KE, Nichols FC. Effect of calcium hydroxide on bacterial lipopolysaccharide. J Endod. 1993;19: 76–8.

101.Safavi KE, Nichols FC. Alteration of biological properties of bacterial lipopolysaccharide by calcium hydroxide treatment. J Endod. 1994;20:127–9.

102.Nelson-Filho P, Leonardo MR, Silva LA, Assed S. Radiographic evaluation of the effect of endotoxin (LPS) plus calcium hydroxide on apical and periapical tissues of dogs. J Endod. 2002;28:694–6.

103.Silva L, Nelson-Filho P, Leonardo MR, Rossi MA, Pansani CA. Effect of calcium hydroxide on bacterial endotoxin in vivo. J Endod. 2002;28:94–8.

104.Tanomaru JM, Leonardo MR, Tanomaru Filho M, Bonetti Filho I, Silva LA. Effect of different irrigation solutions and calcium hydroxide on bacterial LPS. Int Endod J. 2003;36:733–9.

105.Jiang J, Zuo J, Chen SH, Holliday LS. Calcium hydroxide reduces lipopolysaccharide-stimulated osteoclast formation. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2003;95:348–54.

106.Buck RA, Cai J, Eleazer PD, Staat RH, Hurst HE. Detoxification of endotoxin by endodontic irrigants and calcium hydroxide. J Endod. 2001;27: 325–7.

107.Vianna ME, Horz HP, Conrads G, Zaia AA, SouzaFilho FJ, Gomes BP. Effect of root canal procedures on endotoxins and endodontic pathogens. Oral Microbiol Immunol. 2007;22:411–8.

108.Baik JE, Kum KY, Yun CH, Lee JK, Lee K, Kim KK, Han SH. Calcium hydroxide inactivates lipoteichoic acid from Enterococcus faecalis. J Endod. 2008;34:1355–9.

109.Siqueira Jr JF, Rôças IN. Bacterial pathogenesis and

mediators in apical periodontitis. Braz Dent

J. 2007;18:267–80.

110.Siren EK, Haapasalo MP, Waltimo TM, Orstavik D. In vitro antibacterial effect of calcium hydroxide combined with chlorhexidine or iodine potassium iodide on Enterococcus faecalis. Eur J Oral Sci. 2004;112:326–31.

111.Waltimo TM, Ørstavik D, Siren EK, Haapasalo MP.

In vitro susceptibility of Candida albicans to four

disinfectants and their combinations. Int Endod

J.1999;32:421–9.

112.Siqueira Jr JF, Rôças IN, Lopes HP, Magalhaes FA, de Uzeda M. Elimination of Candida albicans infection of the radicular dentin by intracanal medications. J Endod. 2003;29:501–4.

113.Siqueira Jr JF, Rôças IN, Magalhaes FA, de Uzeda

M.Antifungal effects of endodontic medicaments. Aust Endod J. 2001;27:112–4.

114.Siqueira Jr JF, de Uzeda M. Intracanal medicaments: evaluation of the antibacterial effects of chlorhexidine, metronidazole, and calcium hydroxide associated with three vehicles. J Endod. 1997;23:167–9.

115.Gomes BP, Ferraz CC, Garrido FD, Rosalen PL, Zaia AA, Teixeira FB, de Souza-Filho FJ. Microbial susceptibility to calcium hydroxide pastes and their vehicles. J Endod. 2002;28:758–61.

116.Menezes MM, Valera MC, Jorge AO, Koga-Ito CY, Camargo CH, Mancini MN. In vitro evaluation of the effectiveness of irrigants and intracanal medicaments on microorganisms within root canals. Int Endod J. 2004;37:311–9.

117.Siqueira Jr JF, Lopes HP, Uzeda M. Atividade antibacteriana da pasta de hidróxido de cálcio/PMCC/ glicerina contendo diferentes proporções de iodofórmio sobre bactérias anaeróbias estritas e facultativas. Rev Paul Odontol. 1997;19:17–21.

118.Siqueira Jr JF, Lopes HP, Uzeda M. Atividade antibacteriana de medicamentos endodônticos sobre bactérias anaeróbias estritas. Rev Assoc Paul Cir Dent. 1996;50:326–32.

119.Siqueira Jr JF, Magalhães FAC, Uzeda M. Avaliação da atividade antibacteriana de medicação intracanal. Três bases fortes e pastas à base de hidróxido de cálcio e paramonoclorofenol canforado. Rev Gaucha Odontol. 1996;44:271–4.

120.Silveira AM, Lopes HP, Siqueira Jr JF, Macedo SB, Consolaro A. Periradicular repair after two-visit endodontic treatment using two different intracanal medications compared to single-visit endodontic treatment. Braz Dent J. 2007;18:299–304.

121.Grecca FS, Leonardo MR, da Silva LA, Tanomaru Filho M, Borges MA. Radiographic evaluation of periradicular repair after endodontic treatment of dog’s teeth with induced periradicular periodontitis. J Endod. 2001;27:610–2.

122.Siqueira Jr JF, Rôças IN, Favieri A, Machado AG, Gahyva SM, Oliveira JC, Abad EC. Incidence of postoperative pain after intracanal procedures based on an antimicrobial strategy. J Endod. 2002;28:457–60.

123.Siqueira Jr JF, Rôças IN, Riche FN, Provenzano JC. Clinical outcome of the endodontic treatment of teeth with apical periodontitis using an antimicrobial protocol. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2008;106:757–62.

124.Evans MD, Baumgartner JC, Khemaleelakul SU, Xia T. Efficacy of calcium hydroxide: chlorhexidine paste as an intracanal medication in bovine dentin. J Endod. 2003;29:338–9.

125.Podbielski A, Spahr A, Haller B. Additive antimicrobial activity of calcium hydroxide and chlorhexidine on common endodontic bacterial pathogens. J Endod. 2003;29:340–5.

126.Gomes BP, Vianna ME, Sena NT, Zaia AA, Ferraz CC, de Souza Filho FJ. In vitro evaluation of the antimicrobial activity of calcium hydroxide combined with chlorhexidine gel used as intracanal medicament. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2006;102:544–50.

127.Schafer E, Bossmann K. Antimicrobial efficacy of chlorhexidine and two calcium hydroxide formulations against Enterococcus faecalis. J Endod. 2005; 31:53–6.

128.Zerella JA, Fouad AF, Spångberg LS. Effectiveness of a calcium hydroxide and chlorhexidine digluconate mixture as disinfectant during retreatment of failed endodontic cases. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2005;100:756–61.

129.Paiva SS, Siqueira Jr JF, Rôças IN, Carmo FL, Leite DC, Ferreira DC, Rachid CT, Rosado AS. Clinical antimicrobial efficacy of NiTi rotary instrumentation with NaOCl irrigation, final rinse with chlorhexidine and interappointment medication: a molecular study. Int Endod J. 2013;46:225–33.

130.de Oliveira LD, Carvalho CA, Carvalho AS, de Souza Alves J, Valera MC, Jorge AO. Efficacy of endodontic treatment for endotoxin reduction in primarily infected root canals and evaluation of cytotoxic effects. J Endod. 2012;38:1053–7.

131.Davies GE, Francis J, Martin AR, Rose FL, Swain G. 1:6-Di-4’-chlorophenyldiguanidohexane (hibitane); laboratory investigation of a new antibacterial agent of high potency. Br J Pharmacol Chemother. 1954;9:192–6.

132.Milstone AM, Passaretti CL, Perl TM. Chlorhexidine: expanding the armamentarium for infection control and prevention. Clin Infect Dis. 2008;46:274–81.

133.Stanley A, Wilson M, Newman HN. The in vitro effects of chlorhexidine on subgingival plaque bacteria. J Clin Periodontol. 1989;16:259–64.

134.Ohara P, Torabinejad M, Kettering JD. Antibacterial effects of various endodontic irrigants on selected anaerobic bacteria. Endod Dent Traumatol. 1993;9:95–100.

135.Theraud M, Bedouin Y, Guiguen C, Gangneux JP. Efficacy of antiseptics and disinfectants on clinical and environmental yeast isolates in planktonic and biofilm conditions. J Med Microbiol. 2004;53: 1013–8.

136.Denton GW. Chlorhexidine. In: Block SS, editor. Disinfection, sterilization, and preservation. 4th ed. Philadelphia: Lea & Febiger; 1991. p. 276–7.

137.Vianna ME, Gomes BP, Berber VB, Zaia AA, Ferraz CC, de Souza-Filho FJ. In vitro evaluation of the antimicrobial activity of chlorhexidine and sodium hypochlorite. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2004;97:79–84.

138.Rosenthal S, Spangberg L, Safavi K. Chlorhexidine substantivity in root canal dentin. Oral Surg Oral

Med Oral Pathol Oral Radiol Endod. 2004;98: 488–92.

139. Komorowski R, Grad H, Wu XY, Friedman

S.Antimicrobial substantivity of chlorhexidinetreated bovine root dentin. J Endod. 2000;26:315–7.

140.Basrani B, Santos JM, Tjaderhane L, Grad H, Gorduysus O, Huang J, Lawrence HP, Friedman

S.Substantive antimicrobial activity in chlorhexidinetreated human root dentin. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2002;94:240–5.

141.Yesilsoy C, Whitaker E, Cleveland D, Phillips E, Trope M. Antimicrobial and toxic effects of established and potential root canal irrigants. J Endod. 1995;21:513–5.

142.Tanomaru Filho M, Leonardo MR, Silva LAB, Anibal FF, Faccioli LH. Inflammatory response to different endodontic irrigating solutions. Int Endod J. 2002;35:735–9.

143.Maris P. Modes of action of disinfectants. Rev Sci Tech. 1995;14:47–55.

144.Hugo WB, Longworth AR. Some aspects of the mode of action of chlorhexidine. J Pharm Pharmacol. 1964;16:655–62.

145.McDonnel G, Russell AD. Antiseptics and disinfectants: activity, action, and resistance. Clin Microbiol Rev. 1999;12:147–79.

146.Portenier I, Haapasalo H, Ørstavik D, Yamauchi M, Haapasalo M. Inactivation of the antibacterial activity of iodine potassium iodide and chlorhexidine digluconate against Enterococcus faecalis by dentin, dentin matrix, type-I collagen, and heat-killed microbial whole cells. J Endod. 2002;28:634–7.

147.Delgado RJ, Gasparoto TH, Sipert CR, Pinheiro CR, de Moraes IG, Garcia RB, Duarte MA, Bramante CM, Torres SA, Garlet GP, Campanelli AP, Bernardineli N. Antimicrobial activity of calcium hydroxide and chlorhexidine on intratubular Candida albicans. Int J Oral Sci. 2013;5:32–6.

148.Delgado RJ, Gasparoto TH, Sipert CR, Pinheiro CR, Moraes IG, Garcia RB, Bramante CM, Campanelli AP, Bernardineli N. Antimicrobial effects of calcium hydroxide and chlorhexidine on Enterococcus faecalis. J Endod. 2010;36:1389–93.

149.Krithikadatta J, Indira R, Dorothykalyani AL. Disinfection of dentinal tubules with 2% chlorhexidine, 2% metronidazole, bioactive glass when compared with calcium hydroxide as intracanal medicaments. J Endod. 2007;33:1473–6.

150.Gama TG, de Oliveira JC, Abad EC, Rocas IN, Siqueira Jr JF. Postoperative pain following the use of two different intracanal medications. Clin Oral Investig. 2008;12:325–30.

151.Vianna ME, Horz HP, Conrads G, Feres M, Gomes BPFA. Comparative analysis of endodontic pathogens using checkerboard hybridization in relation to culture. Oral Microbiol Immunol. 2008;23:282–90.

152.Malkhassian G, Manzur AJ, Legner M, Fillery ED, Manek S, Basrani BR, Friedman S. Antibacterial efficacy of MTAD final rinse and two percent chlorhexidine gel medication in teeth with apical periodontitis: a randomized double-blinded clinical trial. J Endod. 2009;35:1483–90.

153.Teles AM, Manso MC, Loureiro S, Silva R, Madeira IG, Pina C, Cabeda JM. Effectiveness of two intracanal dressings in adult Portuguese patients: a qPCR

and anaerobic culture assessment. Int Endod J. 2014; 47:32–40.

154.Tervit C, Paquette L, Torneck CD, Basrani B, Friedman S. Proportion of healed teeth with apical periodontitis medicated with two percent chlorhexidine gluconate liquid: a case-series study. J Endod. 2009;35:1182–5.

155.Hasselgren G, Olsson B, Cvek M. Effects of calcium hydroxide and sodium hypochlorite on the dissolution of necrotic porcine muscle tissue. J Endod. 1988;14:125–7.

156.Reit C, Dahlen G. Decision making analysis of endodontic treatment strategies in teeth with apical periodontitis. Int Endod J. 1988;21:291–9.

157.Orstavik D, Kerekes K, Molven O. Effects of extensive apical reaming and calcium hydroxide dressing on bacterial infection during treatment of apical periodontitis: a pilot study. Int Endod J. 1991; 24:1–7.

158.Yared GM, Dagher FE. Influence of apical enlargement on bacterial infection during treatment of apical periodontitis. J Endod. 1994;20:535–7.

159.Lana MA, Ribeiro-Sobrinho AP, Stehling R, Garcia

GD, Silva BK, Hamdan JS, Nicoli JR, Carvalho MA, Farias LM. Microorganisms isolated from root canals presenting necrotic pulp and their drug susceptibility in vitro. Oral Microbiol Immunol. 2001;16:100–5.

160. Kvist T, Molander A, Dahlen G, Reit C. Microbiological evaluation of oneand two-visit endodontic treatment of teeth with apical periodontitis: a randomized, clinical trial. J Endod. 2004;30: 572–6.

161. Chu FC, Leung WK, Tsang PC, Chow TW, Samaranayake LP. Identification of cultivable microorganisms from root canals with apical periodontitis following two-visit endodontic treatment with antibiotics/steroid or calcium hydroxide dressings. J Endod. 2006;32:17–23.

162.Wang CS, Arnold RR, Trope M, Teixeira FB. Clinical efficiency of 2% chlorhexidine gel in reducing intra-

canal bacteria. J Endod. 2007;33:1283–9.

J Endod. 2012;38:1479–83.