Properties and applications of calcium hydroxide …

1 Review Properties and applications of calcium hydroxide in endodontics and dental traumatology Z. Mohammadi1 & P. M. H. Dummer2. 1. Department of Endodontics, Hamedan University of Medical Sciences, Hamedan, Iran; and 2 Endodontology Research Group, School of Dentistry, Cardiff University, Cardiff, UK. Abstract dentine and its toxicity. Pure calcium hydroxide paste has a high pH (approximately ) and is Mohammadi Z, Dummer PMH. Properties and applications classified chemically as a strong base. Its main actions of calcium hydroxide in endodontics and dental traumatology. are achieved through the ionic dissociation of Ca2+.

2 International Endodontic Journal, 44, 697 730, 2011. and OH) ions and their effect on vital tissues, the calcium hydroxide has been included within several induction of hard-tissue deposition and the antibacte- materials and antimicrobial formulations that are used rial Properties . The lethal effects of calcium hydroxide in a number of treatment modalities in endodontics. on bacterial cells are probably due to protein dena- These include, inter-appointment intracanal medica- turation and damage to DNA and cytoplasmic mem- ments, pulp-capping agents and root canal sealers. branes. It has a wide range of antimicrobial activity calcium hydroxide formulations are also used during against common endodontic pathogens but is less treatment of root perforations, root fractures and root effective against Enterococcus faecalis and Candida resorption and have a role in dental traumatology, for albicans.

3 calcium hydroxide is also an effective anti- example, following tooth avulsion and luxation inju- endotoxin agent. However, its effect on microbial ries. The purpose of this paper is to review the biofilms is controversial. Properties and clinical applications of calcium hydrox- ide in endodontics and dental traumatology including Keywords: antimicrobial, apexification, calcium its antibacterial activity, antifungal activity, effect on hydroxide , dental traumatology, endodontics, root bacterial biofilms, the synergism between calcium resorption, vital pulp therapy. hydroxide and other agents, its effects on the proper- ties of dentine, the diffusion of hydroxyl ions through Received 11 November 2010; accepted 29 March 2011.

4 Bacterial biofilms, the synergism between calcium Introduction hydroxide and other agents, its effects on the Properties Materials and therapeutic agents containing calcium of dentine, the diffusion of hydroxyl ions through hydroxide are used extensively in a variety of treatment dentine, and its toxicity. The paper sets out initially to modalities within endodontics and dental traumatology. provide the background to the main clinical applica- The main purpose of this article is to review the tions of calcium hydroxide (Ca(OH)2) and then focuses Properties and clinical applications of calcium hydrox- on its specific Properties and more detailed uses.

5 Ide in endodontics and dental traumatology including its antibacterial activity, antifungal activity, effect on Background Correspondence: Zahed Mohammadi, Department of Endodon- Root canal medicaments tics, Hamedan dental School, Shahid Fahmideh Street, Microorganisms are the cause of apical periodontitis Hamedan, Iran (e-mail: (Kakehashi et al. 1965, Mo ller et al. 1981, Sundqvist 2011 International Endodontic Journal International Endodontic Journal, 44, 697 730, 2011 697. calcium hydroxide in endodontics and dental traumatology Mohammadi & Dummer 1992) and their elimination from the root canal space followed by placement of a calcium hydroxide paste during root canal treatment results in predictable to fill the canal system for 6 24 months (Frank 1966).)

6 Healing of apical pathosis (Bystro m & Sundqvist 1981). Indeed, many studies have demonstrated that Traumatology teeth with infected root canals at the time of canal dental trauma involves damage to teeth and the filling have substantially poorer outcomes than root supporting tissues. Intracanal medicaments containing canals where no culturable microorganisms could be calcium hydroxide are used to control internal resorp- detected (Molander et al. 2007). Unfortunately, the tion (Haapasalo & Endal 2006) as well as inflammatory complete elimination of bacteria by instrumentation apical root resorption (Majorana et al.)

7 2003). Further- alone is unlikely to occur (Bystro m & Sundqvist more, the International Association of dental Trauma- 1981, Wu et al. 2006). In addition, pulp tissue tology (2007) guidelines recommend that any tooth remnants may prevent microorganisms from being with a necrotic pulp associated with a luxation injury entombed (Haapasalo et al. 2007) as well as have a should be dressed with a calcium hydroxide medica- negative impact on the root filling in terms of its ment until the root canal is filled. For avulsion injuries, physical Properties and adaptation to the canal walls the use of calcium hydroxide medicament is recom- (Wu et al.

8 2006). Thus, some form of irrigation and mended for up to 1 month (Kawashima et al. 2009). disinfection is necessary to kill and remove microor- ganisms, their by-products and residual tissue, as well Retrieval of literature as remove the smear layer and other debris from the canal system. Such chemical (therapeutic) treatments A Medline search was performed from 1971 to the end of the root canal can be arbitrarily divided into of 2009 and was limited to English-language papers. irrigants, canal rinses, and inter-appointment medi- The keywords searched on Medline were calcium caments; calcium hydroxide is included in this latter hydroxide AND endodontics (1943)', calcium hydrox- group.

9 Ide AND Enterococcus faecalis (134)', calcium hydrox- ide AND Candida albicans (51)', calcium hydroxide Endodontic sealers AND endotoxin (23)', calcium hydroxide AND dentine Sealers are responsible for the principal functions of (986)', calcium hydroxide AND biofilm (17)', calcium root fillings, which aim to prevent reinfection. That is, hydroxide AND sodium hypochlorite (174)', calcium sealing the root canal system by entombing remaining hydroxide AND chlorhexidine (145)', calcium hydr- bacteria and filling of irregularities in the prepared oxide AND vital pulp therapy (121)', calcium hydrox- canal system ( rstavik 2005).

10 The rationale for the ide AND apexification (138)', calcium hydroxide AND. addition of calcium hydroxide to root canal sealers root fracture (59)', calcium hydroxide AND root eminates from observations of liners and bases con- resorption (203)', calcium hydroxide AND perforation taining Ca(OH)2 and their antibacterial and tissue (32)' and calcium hydroxide AND avulsion (73)'. repair abilities ( rstavik 2005). Then, the reference section of each of those articles was studied to find other suitable sources. The number of Immature teeth with open apices retrieved papers was presented in the parentheses.