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Table of Contents   
ORIGINAL RESEARCH  
Year : 2012  |  Volume : 23  |  Issue : 2  |  Page : 226-229
The effect of calcium hydroxide placement on pH and calcium concentration in periapical environment: An in vitro study


1 Department of Endodontics and Torabinejad Dental Research Center, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran
2 General Dentist, Isfahan University of Medical Sciences, Isfahan, Iran

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Date of Submission29-Oct-2010
Date of Decision15-Mar-2011
Date of Acceptance08-Nov-2011
Date of Web Publication3-Sep-2012
 

   Abstract 

Aims: Comparing the calcium concentration and pH levels of Ca(OH) 2 medicament placing in pulp chamber and root canal.
Materials and Methods: Ninety-nine extracted human mandibular second premolars were instrumented to size #40 k file. Nine teeth served as the control group and the remaining teeth were assigned into two groups. Group 1-Ca(OH) 2 was placed in the dried pulp chamber, while root canals remained wet with normal saline; group 2-Ca(OH) 2 was placed in dried root canals. In control group, canals remained wet without medication. Each group was divided into 3 sub-groups of 15 teeth in which pH and calcium concentration were measured in three intervals of 2 days, 1 week, and 2 weeks by pH meter and atomic absorption spectrometer system, respectively. Findings were assessed using Kruskal-Wallis and t-test.
Results: At 1 and 2 weeks, the calcium concentration had increased without being significantly different from Ca(OH) 2 placed either in the root canal or in the pulp chamber. Ca(OH) 2 placed in the pulp chamber or root canal provided similar pH values (P=0.362).
Conclusions: Placing Ca(OH) 2 in pulp chamber is as effective as placing it in the root canal.

Keywords: Ca(OH) 2 , calcium, pH, periapical

How to cite this article:
Barekatain B, Hasheminia SM, Shadmehr E, Attary Z. The effect of calcium hydroxide placement on pH and calcium concentration in periapical environment: An in vitro study. Indian J Dent Res 2012;23:226-9

How to cite this URL:
Barekatain B, Hasheminia SM, Shadmehr E, Attary Z. The effect of calcium hydroxide placement on pH and calcium concentration in periapical environment: An in vitro study. Indian J Dent Res [serial online] 2012 [cited 2020 Feb 25];23:226-9. Available from: http://www.ijdr.in/text.asp?2012/23/2/226/100431
The number of live bacteria in contaminated canals will be reduced using different techniques and materials such as: Mechanical instrumentation, irrigating and dressing with anti-bacterial interappointment medicaments. The value of Ca(OH) 2 in endodontic treatment of necrotic, infected teeth is now well documented. [1] Ca(OH) 2 is also useful in treatment of root resorption, perforation, apexification, and pulp capping. [2],[3] Effects of Ca(OH) 2 depends on properties of two ions, calcium and hydroxyl, which are released in liquid environment. Hydroxyl group is the most important component because it makes the environment alkalinized, which has anti-bacterial effect and inhibits bacterial growth. Calcium ion promotes repair and calcification of pulp canal. [4],[5] Ca(OH) 2 can kill microorganisms by consuming carbon dioxide, which is necessary for bacterial growth. [6] In necrotic teeth with weeping canals, Ca(OH) 2 dressing makes the canals dry and suitable for obturation. [7]

There are some concerns regarding the use of Ca(OH) 2 . The handling and proper placement of Ca(OH) 2 present a challenge to clinicians. Also, the removal of Ca(OH) 2 is frequently incomplete, even copious irrigation with saline, NaOCl, or EDTA resulting in a residue covering 20% to 45% of the canal wall surfaces. [8],[9] Complete removal of Ca(OH) 2 before obturation of the canal is important to achieve fluid hermetic seal. This process is time consuming and should be done using chemical irrigation simultaneously with reaming motion of the files. [10],[11],[12],[13] Considering the fact that Ca(OH) 2 has an essential role in endodontic treatment, the hypothesis of this study is that placing Ca(OH) 2 in the pulp chamber is as effective as placing it in root canal. Furthermore, placing Ca(OH) 2 in pulp chamber do not contaminate root canal walls and do not interfere with bacterial tight seal, the ultimate goal of endodontic therapy.


   Materials and Methods Top


In this experimental in vitro study, 99 extracted human single-rooted mandibular second premolars with nearly the same lengths (20-22 mm) were collected and immersed in 5% sodium hypochlorite (Pakshoo Co., Iran) for 30 minutes to be disinfected. Adherent tissue and cementum were removed with currette and the teeth were stored in normal saline solution. Standard access cavity was prepared using high speed handpiece with water spray and a diamond fissure bur No. 1 (Tizkavan, Iran). The appropriate working length was measured with file No. 10 (Mani, Japan). A 1 mm short of apex was considered as working length. The root canals were enlarged at the apical foramen with K-files to size 40. A standard flare was produced by instrumentation up to file No. 80. Irrigation during cleaning and shaping was accomplished using 10 ml of 2.5% NaOCl (Aria Dent, Iran). After each instrument, patency was maintained by using file No. 10 or 15, which passed 1 mm beyond the apex. After instrumentation, root canals were irrigated with 10 ml of 2.5%NaOCl, then 3 ml of 17% EDTA (Aria Dent, Iran) for 1 min, followed by a final flush using 3ml NaOCl and 10 ml normal saline. [11] All root surfaces except for the apical 2 mm were covered by two layers of nail polish. Nine teeth served as the control group and remaining teeth were randomly assigned into two experimental groups. In group 1 the access cavity was dried with a cotton pellet and the root canal remained wet after root canal preparation (final flush of 10 ml normal saline) in order to allow hydroxyl and calcium ions to be released. The Ca(OH) 2 paste [0.6 g Ca(OH) 2 powder (Merck, Germany) mixed with 1 ml of normal saline] was inserted into the pulp chamber by spatula. Root canals of the second group were dried with paper point and filled with the Ca(OH) 2 paste by Lentulo spiral No.3 (Dentsply Maillefer). In nine teeth of control group nothing was applied into the wet canals. All access cavities were then filled with 3 mm of Cavit (AryaDent, Iran). They were immersed in 10cc normal saline in capped test tubes individually. The specimens were stored in an incubator (Behdad incubator, Iran) at 37°C in 100% humidity. Then, the samples were again divided into three sub-groups, which were either assessed in A: 2 days, B: 1 week, and C: 2 weeks. These groups contained a total 15 teeth from group 1, 15 teeth from group 2, and 3 teeth from control group. Calcium ion concentration and normal saline pH were measured by atomic absorption spectrometer system (Perkin Elmer, USA) and pH meter (Oakton, Malaysia), respectively.

Statistical analysis

The results were assessed using Kruskal-Wallis and t-tests.


   Results Top


When Ca(OH) 2 was placed in the root canal and pulp chamber, calcium ion concentration in 1 and 2 weeks was significantly higher (P>0.05) than control group, except for 48 hours in which the difference with control groups was not significant [Table 1]. At 1 and 2 weeks, the calcium concentration had significantly increased without being significantly different between the root canal group and the pulp chamber group [Table 1]. The highest calcium concentration was observed after 2 weeks for both groups. The difference in calcium ion concentration between the pulp chamber and root canal was not statistically significant in 1 and 2 weeks (P=0.87), however in 48 hours the concentration of calcium ions were significantly higher in group in which the paste was inserted in pulp chamber.
Table 1: Ca ion concentration means±SD in experimental groups

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The difference in pH values between case and control groups was significant, regardless of location, overall, aqueous Ca(OH) 2 paste placed in the pulp chamber or root canal provided similar pH values during the experimental period (P=0.362) [Table 2].
Table 2: PH means±SD in the experimental groups

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   Discussion Top


The value of Ca(OH) 2 in endodontic treatment of necrotic, infected teeth is well documented. [2],[3],[4],[5],[6] It normally is used as slurry of Ca(OH) 2 in a water base. At body temperature, Ca(OH) 2 is dissolved into calcium and hydroxyl ions. Because it needs water to dissolve, saline is used as the vehicle for the paste. According to Simon et al., [16] normal saline or camphorated paramonocholorophenol result in more favorable release characteristics of the two ionic species than phosphate buffer saline or propylene glycol. Normal saline was used in this study, as Ca(OH) 2 paste generally is produced by mixing the powder with distilled water or saline.

Since temperature of the experimental area is an important factor for evaluating the pH, samples were kept in incubator at 37°C. To simulate in vivo conditions, the test media of normal saline was not renewed after each measurement period.

The desired therapeutic effect of Ca(OH) 2 is in part dependent on the dissociation of Ca(OH) 2 into hydroxyl ion and calcium ion and their diffusion through the apical foramen and dentinal tubules. Moreover, much of the effect is believed to occur via the apical foramen. [14] In this study smear layer was removed, using EDTA 17% and 2.5% sodium hypochlorite, to increase Ca(OH) 2 penetration through apical foramen and root dentin.

There are some concerns regarding the use of Ca(OH) 2 . The handling and proper placement present a challenge to the average clinician. Also, the removal of Ca(OH) 2 is frequently incomplete, resulting in a residue covering 20% to 45% of the canal wall surfaces. It may interfere with the seal of the root canal filling and compromise the quality of treatment. So if Ca(OH) 2 in pulp chamber could have the same result as Ca(OH) 2 in the root canal we can use it without those concerns and it could be washout from the pulp chamber easily.

Our results showed that Ca(OH) 2 in both places (root canal or pulp chamber) can penetrate to periapical area and increased pH and Ca ion concentration by time. Hosaya et al., [15] examined changes in calcium ion concentration and pH changes in transparent root canal models in time intervals as well as the present study, and they reported that the time required for optimum intracanal activity when using Ca(OH) 2 mixtures is at least 2 weeks. In the present study the calcium ion concentration around the root had increased over time in both groups (root canal and pulp chamber). In 1 and 2 weeks the differences of Ca ion concentration between case and control groups were statistically significant. However, in 48 hours the difference between experimental groups and control one was not significant. Our results showed that there was no significant difference in calcium ion concentration in pulp chamber or root canal, except for 48 hours period that we had the higher level of the calcium ion concentration around the root by placing the paste in pulp chamber. We believe that this is probably because Ca(OH) 2 paste in the pulp chamber can quickly release calcium ions by absorbing the moisture from root canal. However, when Ca(OH) 2 is placed in the root canal, it needs more time to obtain moisture from periapical surrounding tissue, to enhance ions releasing.

The results of present study showed that difference in pH changes were not significant between both Ca(OH) 2 placement (pulp chamber or root canal) the same as Perez's study. [17] They demonstrated that in 7 and 14 days there was no significant difference in pH level between pulp chamber and root canal, whereas in 48 hours pH level in group, which Ca(OH) 2 was inserted in pulp chamber was higher. Perez et al. measured hydroxyl ions propagation through the root dentin, yet we measured hydroxyl ion released from the apical foramen.

After the insertion of Ca(OH) 2 in both places (pulp chamber and root canal), there was a significant increase in pH level contrary to control groups, also we had a slight increase in pH value between 48-hours and 1 week and 2 weeks but the difference was not statistically significant. This trend is also seen in the study of Zmener et al., [18] who measured hydroxyl ion propagation from apical foramen after placement of Ca(OH) 2 in root canal. They had used the glass model for this purpose and observed that after 24 hours in the root environment a significant increase in pH occurs, but these differences after two weeks was not significant. The numbers of our study were less than Zmener's results because of buffering effect of natural teeth dentin. [19] Numbers of our finding were lower than Simon's results because in his experimental model, the size of the apical foramen was one millimeter. This large foramen permit more ion diffusion than our study in which, the canal was enlarged only up to size 40 k-file. He also did not use natural teeth as we did in our study.


   Conclusion Top


There is no significant differences in concentration of Ca(OH) 2 ions and pH if Ca(OH) 2 is placed in the pulp chamber or in the root canal. These results show that placing Ca(OH) 2 in pulp chamber is as effective as placing it in root canal. Also, in order to gain the maximum effect without difficulty in cleaning the remained Ca(OH) 2 , it is recommended to use it in pulp chamber and keep it for a longer period of time.

 
   References Top

1.Lin S, Kfir A, Laviv A, Sela G, Fuss Z. The in vitro antibacterial effect of calcium hydroxide in infected dentinal tubules at different time intervals. J Contemp Dent Pract 2009;10:59-66.  Back to cited text no. 1
    
2.Carrotte P. Calcium hydroxide's application in endodontic. Br Dent J 2004;197:735-43.  Back to cited text no. 2
    
3.Orucoglu H, Cabankara FK. Effect of unintentionally extruded calcium hydroxide paste including barium sulfate as a radiopaquing agent in treatment of teeth with periapical lesions: Report of a case. J Endod 2008;34:888-91.  Back to cited text no. 3
    
4.Leonardo MR, da Silva LA, Tanomaru Filho M, Bonifácio KC, Ito IY. In vitro evaluation of antimicrobial activity of sealers in endodontics. J Endod 2000;26:391-4.  Back to cited text no. 4
    
5.da Silva LA, Leonardo MR, da Silva RS, Assed S, Guimarães LF. Calcium hydroxide root canal sealers: Evaluation of pH, Calcium ion concentration and conductivity. Int Endod J 1997;30:205-9.  Back to cited text no. 5
    
6.Kontakiotis EG, Wu MK, Wesselink PR. Effect of calcium hydroxide dressing on seal of permanent root filling. Endod Dent Traumatol 1997;13:281-4.  Back to cited text no. 6
[PUBMED]    
7.Cohen S, Hargreaves KM, Keiser K. Pathway of the pulp. 9 th ed. Mosby Elsevier; 2006. p. 361-2.  Back to cited text no. 7
    
8.Lohbaur U, Dahl U, Dasch W, Petschelt A. Calcium release and PH of gutta-percha points containing calcium hydroxide. J Dent Res 2001;80:272.  Back to cited text no. 8
    
9.Siren EK, Lavonious E, Kontakiotis E. Effect of Ca(OH)2 gutta-percha points on bacteria in root canals. J Dent Res 2000;79:543.  Back to cited text no. 9
    
10.Porkaew P, Retief DH, Barfield RD, Lacefield WR, Soong SJ. Effect of calcium hydroxide paste as an intracanal medicament on apical seal. J Endod 1990;16:369-74.  Back to cited text no. 10
[PUBMED]    
11.Lambrianidis T, Kosti E, Boutsioukis C, Mazinis M. Removal efficacy of various calcium hydroxide/chlorhexidine medicaments from the root canal. Int Endod J 2006;39:55-61.  Back to cited text no. 11
[PUBMED]    
12.Lambrianidis T, Margelos J, Beltes P. Removal efficiency of calcium hydroxide dressing from the root canal. J Endod 1999;25:85-8.  Back to cited text no. 12
[PUBMED]    
13.Margelos J, Eliades G, Verdelis C, palaghias G. Interaction of calcium hydroxide with zinc oxide- eugenol type sealers: A potenial clinical problem. J Endod 1997;23:43-8.  Back to cited text no. 13
[PUBMED]    
14.Farhad A, Barekatain B, Khodarahmi GH. PH Change and calcium ione diffusion from calcium hydroxide intracanal medication through root dentin. Dent Sch Shahid Beheshti Univ Med Sci J 2003;21:374-82.  Back to cited text no. 14
    
15.Pérez F, Franchi M, Péli JF. Effect of calcium hydroxide form and placement on root dentine pH. Int Endod J 2001;34:417-23.  Back to cited text no. 15
    
16.Hosoya N, Takahashi G, Arai T, Nakamura J. Calcium concentration and pH of the periapical environment after applying calcium hydroxide into root canals in vitro. J Endod 2001;27:343-6.  Back to cited text no. 16
    
17.Simon ST, Bhat KS, Francis R. Effect of four vehicles on the pH of calcium hydroxide and the release of calcium ion. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1995;80:459-64.  Back to cited text no. 17
    
18.Zmener O, Pameijer CH, Banegas G. An in vitro study of the pH of three calcium hydroxide dressing materials. Dent traumatol 2007;23:21-5  Back to cited text no. 18
    
19.Haapasalo HK, Sirén EK, Waltimo TM, Ørstavik D, Haapasalo MP. Inactivation of local root canal medicaments by dentine: An in vitro study. Int Endod J 2000;33:126-31.  Back to cited text no. 19
    

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Correspondence Address:
Seyed Mohsen Hasheminia
Department of Endodontics and Torabinejad Dental Research Center, School of Dentistry, Isfahan University of Medical Sciences, Isfahan
Iran
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0970-9290.100431

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