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ABSTRACT:Introduction: Calcium hydroxide is widely used in

the field of endodontics as a temporary root canal filling.This medicament significantly increases pH and optimizesthe treatment outcome. Its total removal before final obtu-ration is very important. Otherwise it could affect the her-metic filling and respectively the endodontic success.

Aim: To evaluate the most effective irrigation pro-tocol of calcium hydroxide removal from root canals.

Materials and methods: In this study 36 single rootcanal teeth were observed. They were randomly dividedinto three groups (n=10 each group) according to the tech-nique applied for calcium hydroxide removal - manual ir-rigation, irrigation and Revo-S rotary instrumentation; andpassive ultrasonic irrigation, and a control group (n=6) –irrigation with distilled water only. After calcium hydrox-ide removals following the procedures above, teeth wereseparated longitudinally in a buccal-lingual direction andremnants of medicaments were observed in the apical, mid-dle and coronal part of each tooth. Then all of the speci-mens were observed using scanning electron microscopyand evaluated by a specified scale. The results have un-dergone statistical analysis.

Results: In the case of calcium hydroxide in the apexand in the middle with highest average is Revo-S, followedby Ultrasonic and irrigation. In the coronal part the high-est average belongs to Revo-S, irrigation and Ultrasonic.In all groups the highest average is represented by controlgroup.

Conclusion: There is not a universal technique forremoval of intracanal medicaments and applying more thanone protocol is required.

Key words: calcium hydroxide, conventional irriga-tion, irrigation protocols, passive ultrasonic irrigation

INTRODUCTION:One of the main purposes in root canal treatment is to

eliminate the infection from the root canal system and toprevent the tooth from reinfection. Many approaches arebeing applied in every day dental practice. One of them isthe application of intracanal medications which affects themicrobiota.

It has been assumed that the microorganisms in theroot canals can be additionally reduced by the use ofinterappointment dressing. These dressings are in fact

EFFICACY OF DIFFERENT ENDODONTICIRRIGATION PROTOCOLS IN CALCIUMHYDROXIDE REMOVAL

Elka N. Radeva, Desislava M. TsanovaDepartment of Conservative Dentistry, Faculty of Dental medicine, MedicalUniversity, Sofia, Bulgaria

Journal of IMAB - Annual Proceeding (Scientific Papers) 2016, vol. 22, issue 4Journal of IMABISSN: 1312-773Xhttp://www.journal-imab-bg.org

intracanal medicaments which have different mechanismsof action. Some authors describe that they help in elimina-tion of unaffected microorganisms [1, 2, 3].

The aim of the dressings is to reduce the quantity ofmicroorganisms that have survived through the chemo-me-chanical preparation. These medicaments also lessen theinflammation, relieve the pain, eliminate the periapical exu-dation, protect the roots from resorption caused by inflam-mation and help to protect the root canal system from rein-fection [4].

Calcium hydroxide is one of the most commonly usedtemporary medicaments in the root canal treatment. It isintroduced in the field of endodontics by Herman as a directpulp capping agent. It has been approved as antimicrobialmedicament for more than 40 years and some authors claimthat maybe this is the best interappointment medicament ofchoice against residual microbiota [5,6]. The mechanism ofaction due to its high pH which can be kept for a long timeallows some authors to introduce the hypothesis for irre-versible inactivation of bacterial enzymes. [7] There are threemain mechanisms of action described in the literature thatdestroy the bacteria in the root canal system: First is Ca(OH)

2

activity based on its high pH, dissociation of ions and re-lease of OH- in water [8]. Second is the action of OH- - theyinduce lipid peroxidation which results in a phospholipiddestruction in the wall of microbial cells. The third mecha-nism is due to its interaction with bacterial DNA which causessegmentation of the two polynucleotide chains and geneloss. This process inhibits the replication of DNA and inac-tivates the function of the microorganisms. Calcium hydrox-ide detoxicates the endotoxin which has been produced fromthe microorganisms in the root canals [9]. Materials con-taining Ca(OH)

2 are water based with a cellulose type thick-

ener which makes them hard to be removed from the rootcanal.

One of the methods for Ca(OH)2 removal from the

root canals which is described most in the literature is thefile instrumentation combined with irrigation of NaOCl andEDTA [10].

Ultrasonic irrigation is another method for removalof intracanal medicaments. There are two methods of ultra-sonic irrigation described in the literature. The first one is acombination of ultrasonic instrumentation and irrigation.In the second method there is a lack of instrumentation andit is known as passive ultrasonic irrigation. The first methodnowadays is rarely used because it does not allow the clini-

https://doi.org/10.5272/jimab.2016224.1355

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cian to control the dentin removal of the canal walls and thefinal shape of the prepared root canal [11, 12]. Passive ultra-sonic irrigation (PUI) is more effective than irrigation withsyringe in dentine debris removal from the canals. Unfortu-nately, it is not clear if PUI can remove the whole Ca(OH)

2

from the root canals.In a perfect situation calcium hydroxide should be

entirely removed from the root canals. Otherwise it mightcompromise the integrity of materials used for obturation ofthe root canals. For example, the thickness of the sealer canchange the sealing ability of the root canal filling materials.Another outcome is that the bone strength of the root canalsealer can be reduced by Ca(OH)

2 remnants left on the root

canal walls and interfere with the sealing ability of a sili-cone-based sealer [3, 13].

All of the above shows the need of more investiga-tions in the field of Ca(OH)

2 application and its removal

from the root canals.

Aim: The aim of this study is to investigate the effec-tiveness of different irrigation protocols used for removal ofcalcium hydroxide used as intracanal medicament.

MATERIALS AND METHODS:In this study 36 single root canal teeth were observed.

The length was standardized at 15 mm, and the root canalswere shaped with Revo-S rotary instruments. The irrigationwas made with 2ml 5.25% NaOCl and 1ml Smear Clear. Allof the canals were dried and filled with Ca(OH)

2. The teeth

were divided into three groups (n=10) according to the tech-nique applied for calcium hydroxide removal - manual irri-gation, irrigation and reshape with Revo-S rotary instru-ments and passive ultrasonic irrigation (PUI), and a controlgroup (n=6) – irrigation with distilled water. After calciumhydroxide removals following the procedures above, teethwere separated longitudinally in a buccal-lingual directionand remnants of medicaments were observed in apical, mid-dle and coronal part of each tooth. Then all of the speci-mens were observed using scanning electron microscopyand evaluated by a specified scale as following: 0 – lack ofCa(OH)

2; 1- less than ½ of the surface is covered with

Ca(OH)2; 2- more than ½ of the surface is covered with

Ca(OH)2; 3- the whole surface is covered with Ca(OH)

2. The

results have undergone statistical analysis.

The following methods were applied:1. Variation analysis – for assessment of the charac-

teristics of the central tendency and scattering data.2. Graphical analysis –for visualization of the re-

sults.3. Nonparametric Shapiro-Wilk test - for verifica-

tion of normality data distribution.4. Nonparametric Kruskal-Wollis test –for verifica-

tion of hypotheses for difference between several unrelatedsamples.

5. Nonparametric Mann Whitney test – for verifica-tion of hypotheses for difference between two unrelatedexcerpts - Checks hypotheses of difference between two un-related samples.

RESULTS:Statistical results about Ca(OH)

2 removal show that:

• In the apical part - significantly highest averagebelongs to the teeth treated with Revo-S followed by Ultra-sonic (PUI) and then Irrigation only.

• In the middle part - with significantly highest aver-age is the group irrigated and reshaped with Revo-S fol-lowed by Ultrasonic and Irrigation. There is no statisticallysignificant difference between last two groups.

• In coronal part - highest average belongs to thegroup of teeth treated with Revo-S followed by Irrigationand Ultrasonic (Fig.1-2, Table 1).

Fig. 1. Comparative analysis of the Ca(OH)2 rem-nants after different cleaning procedures of the root canals.

Table 1. Comparative analysis for the Ca(OH)2

effect on the groups of investigated methods and control groupaccording to the different locations.

LocationRevo-S Ultrasonic Irrigation Control group

n X SD n X SD n X SD n X SDApex 10 2,80a 0,30 10 1,20b 0,30 10 0,80c 0,30 6 3,00d 0Middle 10 1,40a 0,37 10 0,20b 0,30 10 0,20b 0,30 6 3,00c 0Coronal 10 1,40a 0,37 10 0,20b 0,30 10 0,60c 0,37 6 3,00d 0

* - identical letters horizontals mean lack of significant difference and different - the existence of such (p <0.05)

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DISCUSSIONIn a study which was conducted to evaluate the anti-

microbial activity of Calcium hydroxide and otherintracanal medications on various microorganisms it wasfound that Ca(OH)

2 has better activity than antibiotical

medications. This can be explained with its high pH 11-12.5 and the bactericide effect of the OH-. In spite of its highantimicrobial effectiveness, there are resistant species suchas E. faecalis, calcium hydroxide which is the reason for thelack of success in many endodontically treated teeth [14].

Calcium hydroxide should be entirely removed fromthe root canals. Otherwise it might compromise the integ-rity of materials used for obturation of the root canals.

Capar et al. (2014) investigated the effect of differ-ent irrigation methods on calcium hydroxide removal andthey found that in the NaOCl irrigated groups, PUI removedsignificantly more Ca(OH)2 medicament than the othertechniques. In the EDTA/NaOCl irrigated groups, the SAFand PUI removed significantly more Ca(OH)2 than theother techniques. The use of the SAF system with the com-

Reshape withRevo-Sand irrigation

Fig. 2. SEM of dentinal wall in each third of the root canal after removal of Ca(OH)2 by using different irrigationtechnique (x1000)

apex middle coronal

Control groupconventionalirrigationwith distilled water

ConventionalIrrigation

Passive ultrasonicirrigation

bination of EDTA and NaOCl enhanced Ca(OH)2 removalwhen compared with the use of only NaOCl irrigation withthe SAF. Continuous PUI and SAF were more effective thanEndoVac, and conventional syringe irrigation in the re-moval of the Ca(OH)2 medicament from an artificial stand-ardized groove in the apical part of the root canal [15].

According to investigations comparing the efficacyand cleaning effect of different irrigation techniques basedon scanning electron microscopy the best is the sonic irri-gation technique which removes most of the smear layer[2, 16]. Second is the passive ultrasonic irrigation and thethird is the manual irrigation with endodontic files and so-lutions [17]. In our study best results in Ca(OH)2 removalfrom the apical and in the middle part of the root canals isachieved with Revo-S and irrigation, followed by PUI andconventional irrigation.

Many authors have the opinion that there is no ex-isting technique which could fully remove the temporarymedication from the root canal and in spite of the vehiculumin all of the experimental groups can be found remnants

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from the temporary root canal medicament [18]. Accordingto Da Silva et al., 2011 [19] the vehiculum is not impor-tant because the dentin surface stays smeary the same wayafter passive and active ultrasonic irrigation. We achievesimilar results to these in our SEM investigations. No mat-ter what kind of technique for Ca(OH)2 removal we use thereare always remnants left in each part of the root canals. Onlythe quantity of the remnants is different depending on theprotocol used for medicament cleaning.

Other investigators who compare different irrigationprotocols reach the conclusion that none of the irrigantsor a combination between them could totally removeCa(OH)2 but chelators such as citric acid and EDTA givebetter results [20]. Others claim that Canal Brush and Ul-trasound do not have maximum effectiveness but they showbetter results than rotary instrumentation and irrigationtechniques [21] The effects of NaOCl, 17% EDTA, 10% cit-ric acid, 7% maleic acid have been observed as individualtechniques or applied together with different mechanicalpreparation of the root canals (manual and rotary instru-mentation, ultrasonic irrigation etc.). The results are dif-ferent: 17% EDTA and 7 % maleic acid effectively removeCa(OH) 2 aqua destillata and Apexcal while 7% maleic acid

has better efficacy in Metapex removal compared to EDTA.17% EDTA and 0.2% chitosan combined with ultrasonicirrigation cannot totally remove Metapex [22].

The combination of rotary instrumentation and pas-sive ultrasonic irrigation lessens the quantity of residualcalcium hydroxide in comparison to manual preparationand sonic irrigation. Although the impossibility of full re-moval of temporary dressings highline that when manualinstrumentation and irrigation are supported by rotary in-strumentation and ultrasonic irrigation the result is muchcleaner root canals. It is important to be mentioned thatactive ultrasonic irrigation has the potential to alterate theroot morphology. That is why passive ultrasonic irrigationis more highly recommended [23].

Unfortunately, it is still evident that there is a lackof unique working protocol which might be absolutely ef-fective in its application for removal of medicaments andworkable in every clinical situation.

CONCLUSION:There in not a universal technique for removal of

intracanal medicaments and applying more than one proto-col is required.

1. Basrani B, Tjaderhane L, SantosJM, Pascon E, Grad H, Lawrence HP,et al. Efficacy of chlorhexidine- andcalcium hydroxide-containing medi-caments against Enterococcus faecalisin vitro. Oral Surg Oral Med OralPathol Oral Radiol Endod. 2003Nov;96(5): 618-24. [PubMed]

2. Castagnola R, Lajolo C,Minciacchi I, Cretella G, Foti R,Marigo L, et al. Efficacy of three dif-ferent irrigation techniques in the re-moval of smear layer and organic de-bris from root canal wall: a scanningelectron microscope study. G ItalEndod . 2014 Nov;28(2):79–86.[CrossRef]

3. Contardo L, De Luca M,Bevilacqua L, Breschi L, Di LenardaR. Influence of calcium hydroxide de-bris on the quality of endodontic api-cal seal. Minerva Stomatol. 2007 Oct;56(10):509-17. [PubMed]

4. Athanassiadis B, Abbott PV,Walsh LJ. The use of calcium hydrox-ide, antibiotics and biocides as antimi-crobial medicaments in endodontics.Aust Dent J. 2007 Mar;52(1 Suppl):S64-82. [PubMed]

5. Farhad AR, Barekatain B,Allameh M, Narimani T. Evaluation ofthe antibacterial effect of calcium hy-

droxide in combination with three dif-ferent vehicles: An in vitro study. DentRes J (Isfahan). 2012 Mar;9(2):167-72. [PubMed]

6. Mohammadi Z, Shalavi S. Ischlorhexidine an ideal vehicle for cal-cium hydroxide? A microbiologic re-view. Iran Endod J. 2012 Summer;7(3):115-22. [PubMed]

7. Estrela C, Estrela CR, HollandaAC, Decurcio Dde A, Pécora JD. Influ-ence of iodoform on antimicrobial po-tential of calcium hydroxide. J ApplOral Sci. 2006 Jan;14(1):33-7.[PubMed]

8. Kim D, Kim E. Antimicrobial ef-fect of calcium hydroxide as anintracanal medicament in root canaltreatment: a literature review - Part I.In vitro studies. Restor Dent Endod.2014 Nov;39(4):241-252. [CrossRef]

9. Oliveira LD, Leão MV, CarvalhoCA, Camargo CH, Valera MC, JorgeAO, et al. In vitro effects of calcium hy-droxide and polymyxin B on endo-toxins in root canals. J Dent. 2005Feb;33(2):107-14. [PubMed]

10. Lambrianidis T, Kosti E,Boutsioukis C, Mazinis M. Removalefficacy of various calcium hydroxide/chlorhexidine medicaments from theroot canal. Int Endod J. 2006 Jan;

39(1):55-61. [PubMed]11. Andrabi SMUN, Kumar A, Zia

A, Iftekhar H, Alam S, Siddiqui S. Ef-fect of passive ultrasonic irrigation andmanual dynamic irrigation on smearlayer removal from root canals in aclosed apex in vitro model. J InvestigClin Dent. 2014 Aug;5(3):188-193.[CrossRef]

12. van der Sluis LW, Versluis M,Wu MK, Wesselink PR. Passive ultra-sonic irrigation of the root canal: a re-view of the literature. Int Endod J.2007 Jun;40(6):415-26. [PubMed]

13. Barbizam JV, Trope M, TeixeiraE, Tanomaru-Filho M, Teixeira FB. Ef-fect of calcium hydroxide intracanaldressing on the bond strength of aresin-based endodontic sealer. BrazDent J. 2008; 19(3):224-227.[PubMed] [CrossRef]

14. George S, Kishen A, Song KP.The role of environmental changes onmonospecies biofilm formation onroot canal wall by Enterococcusfaecalis. J Endod. 2005 Dec;31(12):867-72. [PubMed]

15. Capar ID, Ozcan E, Arslan H,Ertas H, Aydinbelge HA. Effect of dif-ferent final irrigation methods on theremoval of calcium hydroxide from anartificial standardized groove in the

REFERENCES:

/ J of IMAB. 2016, vol. 22, issue 4/ http://www.journal-imab-bg.org 1359

Address for correspondence: Assoc. Prof. Elka Radeva, PhD.Department of Conservative Dentistry, Faculty of Dental Medicine, MedicalUniversity – Sofia.1, G. Sofiyski Blvd., 1431 Sofia, Bulgaria.E-mail: eliradeva@abv.bg

apical third of root canals. J Endod.2014 Mar;40(3):451-4. [PubMed]

16. Kanter V, Weldon E, Nair U,Varella C, Kanter K, Anusavice K, etal. A quantitative and qualitative ana-lysis of ultrasonic versus sonic endo-dontic systems on canal cleanlinessand obturation. Oral Surg Oral MedOral Pathol Oral Radiol Endod. 2011Dec;112(6): 809-13. [PubMed]

17. Khaord P, Amin A, Shah MB,Uthappa R, Raj N, Kachalia T, et al. Ef-fectiveness of different irrigation tech-niques on smear layer removal in api-cal thirds of mesial root canals of per-manent mandibular first molar: A scan-ning electron microscopic study. JConserv Dent. 2015 Jul-Aug;18(4):321-326. [PubMed]

18. Balvedi RP, Versiani MA,

Manna FF, Biffi JC. A comparison oftwo techniques for the removal of cal-cium hydroxide from root canals. IntEndod J. 2010 Sep;43(9):763-8.[PubMed]

19. da Silva JM, Andrade JuniorCV, Zaia AA, Pessoa OF. Microscopiccleanliness evaluation of the apicalroot canal after using calcium hydrox-ide mixed with chlorhexidine, propyl-ene glycol, or antibiotic paste. OralSurg Oral Med Oral Pathol OralRadiol Endod. 2011 Feb;111(2):260-4. [PubMed]

20. Rodig T, Vogel S, Zapf A,Hulsmann M. Efficacy of differentirrigants in the removal of calcium hy-droxide from root canals. Int Endod J.2010 Jun;43(6):519-27. [PubMed]

21. Tasdemir T, Celik D, Er

K, Yildirim T, Ceyhanli KT, YesilyurtC. Efficacy of several techniques forthe removal of calcium hydroxidemedicament from root canals. IntEndod J. 2011 Jun;44(6):505-9.[PubMed]

22. Vineeta N, Gupta S, Chandra A.Retrievabilty of calcium hydroxideintracanal medicament with Chitosanfrom root canals: An in vitro CBCTvolumetric analysis. J Conserv Dent.2014 Sep;17(5):454-7. [PubMed]

23. Wiseman A, Cox TC, ParanjpeA, Flake NM, Cohenca N, Johnson JD.Efficacy of sonic and ultrasonic acti-vation for removal of calcium hydrox-ide from mesial canals of mandibularmolars: a microtomographic study. JEndod. 2011 Feb;37(2):235-8.[PubMed]

Please cite this article as: Radeva EN, Tsanova DM. Efficacy of different endodontic irrigation protocols in calciumhydroxide removal. J of IMAB. 2016 Oct-Dec;22(4):1355-1359. DOI: https://doi.org/10.5272/jimab.2016224.1355

Received: 12/09/2016; Published online: 28/10/2016