EFFECTS OF DIFFERENT ROOT CANAL IRRIGANTS ON DECALCIFICATION

OF ROOT CANAL DENTIN: AN IN-VITRO STUDY

by

Dr.JOSEPH CHAKKALAMATTATH

Dissertation Submitted to the

Rajiv Gandhi University of Health Sciences, Karnataka, Bengaluru

In partial fulfillment

of the requirements for the degree of

MASTER OF DENTAL SURGERY in the Specialty of

BRANCH IV: CONSERVATIVE DENTISTRY AND ENDODONTICS

Under the guidance of

Dr. M.C. PONAPPA

Coorg institute of Dental Sciences,

Virajpet

2018

6

ACKNOWLEDGEMENT

I would like to express my appreciation to a few important individuals, for all their

contributions which have played an important role in the completion of this thesis.

First and foremost, my sincerest thanks to my guide Professor Dr.M.C.Ponnappa,

for his valuable guidance, constructive criticism and timely suggestions. Sir, I shall always be

grateful to you for your encouragement and moral support.

I also take this opportunity to thank Dr.K.C.Ponnappa, Professor& HOD for his

constant help at all times. I gratefully acknowledge & whole heartedly thank Dr.Girish.T.N,

Professor, for his full support, guidance & constant encouragement.

I am very grateful to all my faculty members – Dr.N.M Ganapathy, Dr.Nanjamma

K.K, Dr. Salin Nanjappa, and Dr.M.Neha Subbaiah for all their guidance, contributions

and moral support.

A significant piece of work involved the analysis of the samples under flame

photometer and I would like to express my gratitude towards Dr.V.O Rejini Professor &

Head of Chemical Department Govt. Engineering college, Thrissur, for her help in carrying

out the same. I would also like to thank Dr.Austin, Head of the Department of Biochemistry

Coorg Institute of Dental sciences, Virajpet for his valuable guidance in the study.

I am also very grateful to my friends; Dr.Nithin Mathew, Dr.Jeffin joseph,

Dr.Jabin O.J, Dr.Poornachandran, Dr.Richie, Dr. Charles, Dr. Sanjeed, Dr.Deepa rose

Sebastian, and Dr. Sandra sunny for their valuable support throughout my life.

I express my heartfelt gratitude to my seniors; Dr.Antony, Dr.Aravind,

Dr.Shameem, Dr.Akhil, Dr.Sajith and Dr.Sarin, to my batch mates; Dr.Jophy, Dr.Joshil,

Dr.Roshan, Dr.Dhanya and Dr.Manju, to my immediate juniors Dr.Vivek A, Dr.Vivek B,

Dr. Deep Shah, Dr.Nileena, Dr.Tintu and Dr. Migha for being such great and fantastic

individuals.

I cannot even begin to articulate what an important role my loving parents Mr. Jiji

John C & Ms. Rani Jiji and my brothers Dr.Paul Chakkalamattath and John

Chakkalamattath have played throughout my life. I dedicate this dissertation to them and

would like to express my gratitude for all their endless sacrifices, their love and support

which always motivated me and moulded me into the person I am today.

7

Most of all I would like to thank God Almighty for all his blessings & kindness and

for having given me the opportunities to try and give my best, into all that life has to offer. I

bow in front of the Almighty without whose blessings none of this would have been possible.

THANK YOU GOD!.

Place: Virajpet.

Date: Dr. JOSEPH CHAKKALAMATTATH

8

LIST OF ABBREVIATIONS

Ca2+ - Calcium ion.

Ca(OH)2 - Calcium hydroxide

CHX - Chlorohexidine

CTR - Cetrimide

EA - Etidronic acid

EDTA - Ethylene diamine tetra acetic acid

Er:YAG - Erbium doped Yttrium Aluminium Garnet laser.

FTIR - Fourier Transform Infrared Spectroscopy

MA - Maleic acid

MTAD - Mixture of Tetracycline isonomer Acid and Detergent.

NaOCl - Sodium hypochlorite

PA - Peracetic acid

PPM - Parts per million

SEM - Scanning Electron Microscope

SX - Sterilox

9

LIST OF TABLES

Table no. Tittle Page No:

Table 1

Comparisson Of Decalcification Effects Of Different Root

Canal Irrigants

23

Table 2

Inter Group Comparison Between Different Groups

23-24

10

LIST OF FIGURES

Sl.No.

Title

Page no.

1.

Mean Ca2+ displacement- Graph

24

2

Sectioned Samples for MTAD Group

40

3

Sectioned Samples for Qmix group

40

4

Sectioned Samples for Smearclear group

41

5

Sectioned Samples for Control group

41

6

Sectioned Samples for 2% CHX

41

7

Electromagnetic stirrer

43

8

Flame photometer

43

Abstract

12

ABSTRACT

INTRODUCTION:

Successful root canal therapy relies on the combination of proper instrumentation, irrigation,

and obturation of the root canal. Smear layer is formed regardless of the instrumentation

technique used during biomechanical preparation. Ideally, all microorganisms and smear layer

that is created during instrumentation should be removed, so that root canal filling will adapt

to the canal perfectly. Hence removal of smear layer requires the use of irrigants that can

dissolve both organic and inorganic components. A very few studies were only reported to state

the decalcification effects of the irrigants. Hence this study was undertaken to compare the

decalcification effects of different irrigants.

METHODS:

Fifty premolar teeth with single canals were collected and decoronated. Tooth is then splited

into two equal halves and pulp tissues were removed. Root surface were then covered with

cyanoacrylate glue except root canal lumen. Tests solution were prepared of 10ml of each

irrigants and grouped. All the collected teeth had been cleaned, splited into two equal halves

and pulp tissues were removed. Root surfaces were then covered with cyanoacrylate glue

except root canal lumen. Tests solution were prepared of 10ml of each irrigants and grouped.

(n=10)

GROUP I : Samples immersed in 37% Phosphoric acid

GROUP II : Samples immersed in Smear clear

GROUP III : Samples immersed in Qmix

GROUP IV : Samples immersed in MTAD

GROUP V: Samples immersed in 2% Chlorohex glucanate

Tooth were dived equally and placed into sample solution and paced it over the magnetic stirrer

for 5 minutes. 5 readings of 0.1 ml solution is taken from each group and aspirated into flame

photometer for the analysis of the displaced calcium.

Abstract

13

Results:

Samples were evaluated for the amount of calcium displaced from the radicular dentin at an

interval of 5 minutes. While comparing the above results, SmearClear showed the maximum

calcium displacement followed by MTAD, Qmix and 2% CHX.

Conclusion:

Within the limitations of the methodology followed and procedures performed; following

were drawn from this study.

Smear Clear had displaced more calcium from the root canal while comparing other

root canal irrigants.

2% CHX expressed the least calcium displacement

Introduction

14

INTRODUCTION

Successful root canal therapy relies on the combination of proper instrumentation, irrigation,

and obturation of the root canal. Of these three essential steps, cleaning & shaping of the root

canal along with appropriate choice of root canal irrigants is one of the most important

determinants in the healing of the periapical tissues. The primary endodontic treatment goal

must thus be to optimize root canal disinfection and to prevent reinfection.

Irrigants can be mainly divided into antibacterial and decalcification or their combinations. Not

all root canal solutions are decalcifying agents and they are mainly used for removal of smear

layer. Smear layer is formed regardless of the instrumentation technique used during

biomechanical preparation. Ideally, all microorganisms and smear layer that is created during

instrumentation should be removed, so that root canal filling will adapt to the canal perfectly.

Hence removal of smear layer requires the use of irrigants that can dissolve both organic and

inorganic components. However, no single solution has been able to achieve these goals, so the

combined, concomitant or sequential use of two or more irrigating solutions is required.1

Currently, sodium hypochlorite (0.5-5.25%) and EDTA (15-17%) are the two most commonly

used intracanal irrigants2-4. NaOCl acts as a solvent of organic material and is a potent primary

antimicrobial agent, it has a wide range of activity against gram-ve and gram+ve bacteria, while

EDTA serves as an inorganic solvent or chelating agent. Chelating agents were introduced to

endodontics by Nygaard-Ostby in 1957 as an aid for the preparation of narrow and calcified

canals. Ethylenediaminetetraacetic acid (EDTA), citric acid and tetracycline are commonly

used for removal of the inorganic portion of the smear layer. EDTA can be used in the form

of a gel or liquid. MTAD Is an alternative solution to EDTA for removing the smear layer,

MTAD™ (DENTSPLY Tulsa Dental Specialties, Tulsa, Okla.) is a mixture of tetracycline

isomer, an acid (citric acid) and a detergent. It has sustained antimicrobial activity superior to

CHX, biocompatible and enhance bond strength. 2%CHX is now advocated as an intracanal

medicament. It’s used alone as a gel or combination with Ca(OH)2. The combination of

2%CHX with Ca(OH)2 has high antimicrobial activity than the combination of Ca(OH)2with

saline. QMix is an irrigant which is available as 2 in 1 solution and contains a mixture of a bis

biguanide antimicrobial agent, a polyaminocarboxylic acid calcium-chelating agent, and a

surfactant and has been found to be effective against bacterial biofilms.

A very few studies were only reported to state the decalcification effects of the irrigants. Hence

this study was undertaken to compare the decalcification effects of different irrigants.

Aim &Objectives

15

AIM

To compare the decalcification effects of MTAD, Qmix , Smearclear and 2%CHX.

OBJECTIVE OF THE STUDY

1. To evaluate the decalcifying effect of Qmix.

2. To evaluate the decalcifying effect of MTAD.

3. To evaluate the decalcifying effect of Smearclear.

4. To evaluate the decalcifying effect of 2% CHX.

Review of literature

16

REVIEW OF LITERATURE

1) A study was conducted to determine the efficacy of 17% EDTA plus 1.25% sodium lauryl ether

sulfate(EDTA-T), 10% citric acid, 17% EDTA with respect to calcium extraction and concluded

that both 10% citric acid and 17% EDTA are good decalcifying agents5.

2) A study was conducted to compare the efficacy on smear layer removal of 4 decalcifying agents:

17% EDTA, 20% citric acid, BioPure MTAD and Smear Clear and concluded that 17% EDTA was

better than MTAD and smear clear6.

3) A study was done to measure the demineralization capability of 1 and 10% citric acid,10% sodium

citrate and 17% EDTA during immersions of 5, 10, 15 minutes on root canal dentin and concluded

that citric acid at 10% was most effective decalcifying agent, followed by 1% citric acid,17% EDTA

and 10% sodium citrate7.

4) A study was done to compare to evaluate the effect of initial use of NaOCl on the decalcification

and erosion ability of EDTA and Qmix, found that the rate of calcium removal and root canal wall

erosion was considerably more severe with the use of 5% NaOCl for 3 min. Qmix as a final solution

showed less decalcification and erosion than 17% EDTA when used 5% NaOCl as an initial irrigant8.

5) An another study was done to evaluate the effects of Ethylenediaminetetraacetic (EDTA),

etidronic (EA) and peracetic acid (PA) when used in conjunction with sodium hypochlorite (NaOCl)

as root canal irrigants on calcium eluted from canals, smear layer, and root dentine demineralization

after instrumentation/irrigation and concluded that, Irrigation protocols employing 1% NaOCl and

then 17% EDTA, 1% NaOCl and then 2.25% peracetic acid, or a combined solution containing 1%

NaOCl and 9% etidronic acid left similar amounts of smear layer on instrumented root canal walls9.

6) A spectroscopic study was done to investigate the effects of several decalcifying agents alone and

in combination with sodium hypochlorite (NaOCl) on the organic and inorganic components of

dentine using Attenuated Total Reflectance in Fourier Transform Infrared Spectroscopy (ATR -

FTIR). 0.9% saline, 9% and 18% etidronic acid (HEDP), 5% and 10% tetrasodium EDTA

(EDTANa 4), 17% trisodium EDTA (EDTAHNa 3), and 0.5% and 2.0% peracetic acid (PAA) for

0.5 - 10 min. Results concluded that HEDP and EDTANa 4 caused minor while EDTAHNa 3 and

PAA caused greater demineralization of dentine, both effects were time and concentration

dependent10.

Review of literature

17

7) A study was done to evaluate the effect of reducing surface tension in endodontic chelator

solutions on their ability to remove calcium from instrumented root canals and results concluded that

none of the solutions with reduced surface tension chelated more calcium from canals than their pure

counterparts11.

8) A study was done to assess the decalcifying Effect of Different root canal irrigants of the

following, Tetraclean, Largal Ultra, 17% ethylenediaminetetraacetic acid, Tubuliclean). Results

concluded that the higher release of Ca2+ was observed in samples treated with Tetraclean; this citric

acid–based agent showed significantly higher decalcifying capability. For all irrigating solutions

tested, 10 minutes of application are sufficient to obtain the maximum Ca2+release12.

9) A study aimed to evaluate the effects of Sterilox (Sx), a super oxidized water, 5% and 2%

sodium hypochlorite (5NaOCl and 2NaOCl), and 17% EDTA (E) on the organic and inorganic

components of bovine dentin. The results concluded that five percent NaOCl promoted the most

extensive damage to the organic component of dentin, and when associated to EDTA, dentinal

erosion could be seen. Considering these specific aspects, 2% NaOCl and Sterilox (Sx) had milder

effects on bovine root dentin13.

10) A study was done to compare the effect of following different irrigants on root dentin micro

hardness and smear layer removal,( 2.5%NaOcl, 2.5%NaOCl+Malic acid, 2.5% NaOCl followed by

17% Ethylenediaminetetraacetic acid (EDTA), 2.5% NaOCl followed by mixture of tetracycline,

acid and detergent (MTAD) and saline.) Results concluded that Maliec acid is the most efficient final

irrigant solution after NaOCl irrigation throughout instrumentation14.

11) A study was done to evaluate the effect of Morinda Citrifolia Juice (MCJ) on smear layer

removal and micro hardness value of root canal dentin in compared with various endodontic

irrigants. Results concluded that 6% MCJ followed by a final flush of 17% EDTA can be regarded

as an effective solution on smear layer removal without any adverse influence on micro hardness

property of root canal dentin15.

12) A study was done to evaluate the cleaning efficacy of different irrigant agitation

techniques on debris and smear layer removal in curved root canals. Results concluded that in

curved root canals, activation of NaOCl and Ethylenediaminetetraacetic acid did not enhance

debris removal but resulted in significantly more effective smear layer removal at coronal

levels16.

Review of literature

18

13) A study was done to determine the effectiveness of laser on final irrigants and observe

smear layer removal from coronal, middle, and apical third region of root canal. Results

concluded that Er: YAG PIPS showed maximum smear layer removal in coronal, middle and

apical third region on 17% EDTA activation17.

14) A study was done to measure the demineralization capacity of 10% and 20% citric acid

and 17% EDTA after three time periods and to determine whether it was modified by the

addition of 1% of commercial chlorhexidine (CHX) and concluded that addition of 1% CHX

did not modify the demineralizing capacity of these solutions18.

15) A study was done to investigate smear layer removal and erosive capacity of different

concentrations of EDTA on instrumented root canal walls (15%, 10%, 5%, and 1%) and

concluded that Lower concentrations of EDTA can be recommended for clinical usage to

avoid excessive erosion of root canal dentin19.

16) A study was done to evaluate the effect of single and combined use of ethylenediamine

tetra acetic acid (EDTA), ethylene glycol bis [b-aminoethylether] N,N,N′,N′-tetraacetic acid

(EGTA), EDTA plus Cetavlon (EDTAC), tetracycline-HCl, and NaOCl on the micro

hardness of root canal dentin.and concluded that The use of EDTA alone or prior to NaOCl

resulted in the maximum decrease in dentin micro hardness. The softening effect of

subsequent NaOCl treatment was both material and region dependent. However, for

combined treatment regimens, subsequent use of NaOCl levels the statistical differences

between the regional micro hardness values obtained after treatment with EGTA, EDTAC,

and tetracycline-HCl20.

17) A study was to find a relation between erosion and micro hardness of root canal dentin

after irrigation with different canal irrigants. Results concluded that 17% EDTA the most

erosive effect on dentin along with the least decrease of dentin micro hardness at depth of,

whereas MTAD showed the most reduction of dentin micro hardness and less erosive effect

on dentin21.

18) A study was done to evaluate the Effects of combined and single use of EDTA, RC Prep,

and NaOCl on mineral content of root dentin and concluded that results showed that EDTA

combined with NaOCl irrigation as final flush and NaOCl alone changed the

calcium/phosphorus ratio of root dentin significantly22.

Review of literature

19

19) A study was done to compare the efficacy of SmearClear, 17% EDTA, and 10% citric

acid in smear layer removal and the results showed that there were no significant differences

in the efficacy of three chelating agents at all levels of the root canals23.

20) A study was to investigate the effect of various concentrations of sodium hypochlorite

(NaOCl) as an intracanal irrigant before the use of MTAD as a final rise to remove the smear

layer. The results showed that MTAD removes most of the smear layer when used as an

intracanal irrigant24.

21) A study was done to quantify the amount of calcium ions removed from the root canal by

etidronicacid (HEBP), BioPure MTAD, and SmearClear using atomic absorption

spectrophotometer. Results concluded that SmearClear was the most effective agent for the

removal of calcium ions from the root canal.25

22) A study was done to measure the demineralization capability of 1 and 10% citric acid,

10% sodium citrate and 17% EDTA during immersions of 5, 10 and 15 min on root canal

dentine results concluded that 1 and 10% citric acid were more effective than EDTA or

sodium citrate at the three immersion times.26

Materials & metodology

20

MATERIALS AND METHODOLOGY

Source of data:

Fifty premolar teeth with single canals were collected from the Department of Oral and Maxillofacial

Surgery and stored in saline.

Method of Collection of Data:

Selection of Teeth:

Inclusion criteria:

Sound caries free single canal premolar teeth extracted for orthodontic reasons.

Exclusion criteria:

Teeth with more than one canal, immature root apices, carious teeth with fracture or craze lines, thinly

curved roots and malformed teeth.

Materials:

i. 50 Single canal human premolar teeth.

ii. MTAD (Dentsply Tulsa Dental, Tulsa, OK, USA. LOT 161027)

iii. Qmix (Dentsply Sirona, USA. LOT 170920)

iv. 2%CHLOROHEX GLUCANATE (Asep-RC, Anabond Stedman Pharma Research.

Chennai.)

v. Smear clear (SybronEndo,CA. LOT 6824437)

vi. 37% Phosphoric acid

vii. Cyanoacrylate glue

viii. Saline

ix. 0.5 Chloramine

x. Distilled water

xi. Diamond disc

xii. Flame photometer (Systronics, single channel128, Mumbai.)

xiii. Magnetic stirrer

Materials & metodology

21

Grouping Of Teeth:

The teeth were divided into 5 groups depending on root canal irrigants to be used.

Methodology:

All the collected teeth had been cleaned, split into two equal halves and pulp tissues were

removed. Root surface were then covered with cyanoacrylate glue except root canal lumen. Tests

solution were prepared of 10ml of each irrigants and grouped. (n=10).

GROUP I : Samples immersed in 37% Phosphoric acid

GROUP II : Samples immersed in Smearclear

GROUP III : Samples immersed in Qmix

GROUP IV : Samples immersed in MTAD

GROUP V : Samples immersed in 2% CHX

Tooth were divided equally and placed into sample solution and placed it over the magnetic stirrer for

5 minutes. 0.1 ml solution was taken from each group and aspirated into flame photometer for the

analysis of the displaced calcium. Five readings from each groups was taken to avoid any error in the

readings.

Results

23

RESULTS

TABLE 1: COMPARISON OF DECALCIFICATION EFFECTS OF DIFFERENT ROOT

CANAL IRRIGANTS (ONE WAY ANOVA).

Mean Standard

deviation F Sig .

Group 1 (37%

Phosphoric acid) 386.7800 1.87803

37143.431

0.000 (H.S) Group 2 (Smear clear) 325.8800 1.26372

Group 3 (Qmix) 288.8800 1.26372

Group 4 (MTAD) 310.1480 1.11701

Group 5 (2% CHX) 51.0600 1.80083

Table 1 shows amount of Mean calcium displaced from the radicular dentin at an interval of 5

minutes. While comparing the above results, Group 2 showed the maximum mean calcium

displacement of 325.8800 followed by Groups 4, 3 and 5

TABLE 2: INTER GROUP COMPARISON USING POST-HOC TUKEY TEST

Mean

difference

Standard

error Sig.

95% Confidence Interval

Lower

Bound

Upper

Bound

Group 1

(37%

Phosphoric

acid)

Group 2

(Smear

clear) 60.9000 .94707

0.000

(H.S) 58.0660 63.7340

Group 3

(Qmix) 97.900 .94707

0.000

(H.S) 95.0660 100.7340

Group 4

(MTAD) 76.632 .94707

0.000

(H.S) 73.7980 79.4660

Group 5

(2% CHX) 335.700 .94707

0.000

(H.S) 332.8860 338.5540

Group 2

(Smear

clear)

Group 3

(Qmix) 37.000 .94707

0.000

(H.S) 34.1660 39.8340

Group 4

(MTAD) 15.732 .94707

0.000

(H.S) 12.8980 18.5660

Results

24

Group 5

(2% CHX) 274.820 .94707

0.000

(H.S) 271.9860 277.6540

Group 3

(Qmix)

Group 4

(MTAD) -21.268 .94707

0.000

(H.S) -24.1020 -18.4340

Group 5

(2% CHX) 237.820 .94707

0.000

(H.S) 234.9860 240.6540

Group 4

(MTAD)

Group 5

(2% CHX) 259.088 .94707

0.000

(H.S) 256.2540 261.9220

Table 2 shows the inter group comparison using a post hoc tukey test. Comparison among the

test groups, showed had a highly statistically significant difference between them.

Graph 1 shows the Mean calcium displaced from the root canal dentin at a time period of 5

minutes.

0

50

100

150

200

250

300

350

400

CALCIUM DISSOLUTION

386.78

325.88

288.88310.148

51.06

37% PHOSPHORIC ACID SMEAR CLEAR QMIX MTAD 2% CHX

Discussion

25

DISCUSSION

The main objectives of endodontic therapy are to remove the diseased tissue, eliminate the

bacteria present in the canals, dentinal tubules and prevent recontamination after treatment.

Current concepts of chemo-mechanical preparation imply that chemicals should be applied on

instrumented root canal surfaces in order to remove the formed smear layer in the radicular

dentin.

The decalcifying effect of chelators in the removal of inorganic content of the smear layer and

negotiation of the fine, tortuous and calcified canal to ascertain patency depends on many

factors. This include the root length, application time, diffusion into the dentin, relationship

between the amount of available active substance (chelator) and the canal wall surface area

and especially, pH of the solution, because the demineralization process continues until all

chelating agents have formed complexes with calcium.25

Although the effects of demineralizing solutions on restorative /dentin bond strength have

been extensively evaluated, little is known about the effects of such solutions on the

mechanical properties of the dentin substrate. Stress distribution at the restorative /dentin

interface depends on the mechanical properties of its components. Chemical pre-treatments

induce considerable changes in the surface morphology and physical properties of dentin.

This study quantified the amount of calcium ions chelated, by different root canal irrigation

solutions, from the root canal, using flame atomic emission photometry or flame photometry.

Atomic absorption spectrometry, Flame photometry, complexometric titration with EDTA,

SEM, Energy dispersive spectrometer, Fourier Transform Infrared (FTIR) or inductively

coupled plasma–atomic emission spectroscopy (ICP-AES) are the different methods

employed to evaluate the demineralization effect of different chemicals, provided that

calibration is accomplished precisely.27

Discussion

26

Flame photometry (more accurately called Flame Atomic Emission Spectrometry) is a branch

of spectroscopy in which the species examined in the spectrometer are in the form of atoms.

A photoelectric flame photometer is an instrument used in inorganic chemical analysis to

determine the concentration of certain metal ions, among them sodium, potassium, calcium

and lithium. Flame Photometry is based on measurement of intensity of the light emitted

when a metal is introduced into the flame.

In principle, it is a controlled flame test, with the intensity of the flame colour quantified by

photoelectric circuitry. The intensity of the colour will depend on the energy that has been

absorbed by the atoms that was sufficient to vaporise them. The sample is introduced to the

flame at a constant rate. Filters select which colours the photometer detects and exclude the

influence of other ions. Before use, the device requires calibration with a series of standard

solutions of the ion to be tested.

Quantitative analysis is performed by measuring the flame emission of solutions containing

the metal salts. Optical filters are used to select the emission wavelength monitored for the

analyte species.

In the present study, experiments were conducted on intact uninstrumented root canal dentin.

The rationale behind this procedure was to enable measurement of Ca2+ loss that occurred

solely on intact root dentin, while avoiding any possible “contamination” of readings that

could have been caused by the Ca2+ incorporated into the loosely bound smear.

The significant alteration in dentin hardness after irrigation indicates the potent direct effect

of the chemical solutions on the components of dentin structure and it has to be considered in

conditions with thinned root canal walls or immature root dentin where loosing too much of

mineral content will adversely affect the longevity of the tooth.28

Adhesive restoration of endodontically treated teeth, generally involves the pulp chamber,

whose mineral content is adversely affected by exposure to endodontic irrigants and this

region generally does not contain much of smear layer because of the conservative nature of

endodontic access cavity preparation. Finally, the extent of Ca2+ removal by the tested

chemicals might be reduced in the presence of smear.

All decalcification procedures were carried out on the same day at the same room

temperature, because an increase in temperature accelerates the demineralization process.

Three immersion periods were studied, as has been done previously (Silveira 1990)7,

Discussion

27

although the periods were shorter (5 minutes) in the present study. The solution was not

renewed between immersions. Renewal of the solution increases the effectiveness of its

action compared with a single continuous application over the same time period (Weinreb &

Meier 1965) because it maintains the pH at neutral levels, thereby increasing its moisturizing

and decalcifying capacity (Perez et al.1989).26Ulusoy and Gorqul used the irrigants for 5

minutes, as duration is important in clinical practice. In the present study, in order to

understand the effects of each sample solution & their decalcification potential, the contact

time was kept at a constant of 5 minutes, since the recommended usage time varies according

to different manufacturers. For calcium analysis 0.1ml of test solution was taken from each

group 5 times to avoid bias. All the 5 readings were taken at same period, since the readings

might change with increase in contact time.

The pH of BioPure MTAD is 2.15, so it contributes to its role as a calcium chelator, thereby

causing enamel and root surface demineralization29. The extent of dentin surface

demineralization is comparable to that of citric acid, and it mainly removes the inorganic

substances. BioPure MTAD contains Citric acid and Tween 80. Citric acid is a crystalline

organic acid, antibacterial and helps in removal of smear layer, in concentration of 10% and

25%, thus helping deeper penetration of doxycycline into the dentinal tubules and exerting its

antibacterial action. Tween 80 (poly oxyethylene sorbitan mono oleate) is a detergent present

in MTAD and is a non-ionic surfactant. It helps in reducing the surface tension of distilled

water. Godoy et al, stated that both MTAD and EDTA decrease the microhardness of root

canal dentin because they induce collapse of the dentin matrix structure. The effect of MTAD

on decreasing dentin microhardness may be attributed to its chelating components. The 3%

doxycycline hyclate component of MTAD is an isomer of tetracycline. Tetracycline has a low

pH and thus can act as a calcium chelator and cause root surface demineralization.21

Moreover, MTAD consists of 4.25% citric acid, which is capable of dissolving the mineral

contents of dentin (67%). Torabinejad et al. showed that MTAD is an effective solution for

the removal of smear layer and does not significantly change the structure of the dentinal

tubules when canals are irrigated with NaOCl followed with a final rinse of MTAD.19

De-Deus et.al, stated that although citric acid has the same concentration as that of EDTA,

their pH were different. The more the acidic pH, the more the removal of calcium ions from

dentin.

Discussion

28

Considering the above mentioned facts with the results of the present study, MTAD group

showed a mean valve of 310.148 and it had a significant difference among the other groups.

It showed a mean difference of 76.63 from the control group, whereas comparing with other

groups, it has a less significant difference among the group II (SmearClear) and group III

(Qmix) respectively. While comparing with Group IV (CHX) it had a greater significant

difference.

Interestingly, the chlorhexidine group showed a few calcium displacement, though it doesn’t

contain any known chealator’s present. It may be because it is a cationic compound. CHX has

the ability to bind anionic molecules such as phosphate present in the structure of

hydroxyapatite. Phosphate exists in the calcium carbonate complexes in dentin. CHX can

bind phosphate, which in turn can lead to the release of small amounts of Ca2+ from the root

canal dentin. Provided that this assumption is true, CHX might show a possible indirect effect

on the removal of Ca2+ by binding the phosphate28.

While considering the above discussed effects of CHX on dentine, these might be the reason

why 2% CHX showed the least amount of the calcium displaced in our study. CHX had

expressed mean value of 51.0600 ppm which is much less when compared with other groups.

In contrast with the results of our study Ari et al, using the ICP-AES technique, reported a

significant decrease in the calcium and phosphorus levels of dentin after using 0.2% CHX as

irrigation solution21.

Nowadays, Ethylene diamine tetra acetic acid (EDTA) and Citric acid are the most

commonly used chemicals for the instrumentation of root canals and smear layer removal.

However, alternative chemicals to remove the smear layer have also been suggested such as

EDTAC (EDTA + cetavlon), EGTA (ethylene glycolbis (β‑aminoethylether)‑N, N, N’,

N’‑tetra acetic acid, maleic acid, per acidic acid, etc. Studies have reported that EDTA or

citric acid strongly reacts with NaOCl, thus making the latter ineffective. The recommended

pH of EDTA solutions for decalcification is around 7.3 while for citric acid it is 0.8–1.9.

In a gravimetrical analysis, Seidberg and Schilder showed that the properties of chelators

(EDTA) were self‑limiting, because of pH changes during the demineralization of dentin.

Under normal conditions, most chelators have an almost neutral pH. Because of the release of

the acid by interchange of calcium from dentin with hydrogen, the efficiency of EDTA

decreases with time; on the other hand, the reaction of the acid with hydroxyapatite affects

Discussion

29

the solubility of dentin. Hülsmann and Hahn in their study demonstrated that EDTA solutions

demineralized dentin up to a depth of 50 μm per canal wall.25

While having minimal effects on the mechanical properties of dentin and having desirable

antimicrobial effect, especially reinfection or failed endodontic cases, QMix has been

recommended as an alternative to EDTA. Therefore, this study evaluated the decalcification

capability of QMix on root canal dentin8. QMix is an EDTA-based solution that also contains

chlorhexidine (CHX) and a detergent as surfactant. QMix is comprised of a combination of

the aforementioned substances that can have different effects when used in a mixed solution.

The addition of a surfactant to the chelating agent leads to a reduction in dentine micro

hardness as it reduces surface tension and hence increases the ability of the chelator to

penetrate the dentine. Therefore, it would have been expected that QMix would reduce

dentine micro hardness more than the combined use of 17% EDTA + 2% CHX. Contrary to

this expectation, however, the results of the present study demonstrated the mean calcium

removal value of 288.8800 ppm which was lower when compared with Groups II and IV.

Irrigants must be in contact with the dentin walls for effective debris removal and penetrate

more readily into the root canal system, thus making more surface area available for action.

The closeness of this contact is directly related to its surface tension. According to Grossman

and Meiman, low surface tension is one of the ideal characteristics of an irrigant.

These views are in support of our study, in which SmearClear was found to be most efficient

in removing Ca2+ ions from root canal than all others, this may be because of low surface

tension (33 mJ/m2) resulting from the presence of additional surfactants. This leads to a

better flow of chelating solution inside the canal25. However, other studies have shown that

the reducing surface tension of chelators did not enhance their calcium‑binding ability. This

is in contrast to our study were the SmearClear showed the mean amount of 325.8800ppm

calcium displaced while comparing with the other groups, which was higher when comparing

with the mean of other groups.

Under the methodological limitations of this study, while evaluating the above results, it is

difficult to co-relate it directly with clinical scenario, since the contact time of irrigants

differs according to manufacturer’s instruction. It should also be noted that, concentration of

the solutions might decrease as the time of the interaction between the ions increases. And

Discussion

30

there is a certain amount of dentin lost during the preparation of the teeth samples, while

sectioning of tooth and during decoronation, all of which were done in the present study.

Although CHX showed the least calcium removal in our study, it’s still used as an effective

root canal irrigant as it is proven to have good antimicrobial property and is very effective in

re-treatment cases. Hence newer root canal irrigants are focused towards a combination of

chelation along with antimicrobial property. In our study both Qmix and MTAD had better

results in the removal of calcium.

Further investigations regarding effects of instrumentation on the radicular dentin and their

effects in bonding & strength should be done to attain better clarity about the chealator’s

which are used routinely in endodontics.

Conclusion

32

CONCLUSION

Within the limitations of the methodology followed and procedures performed; following

were drawn from this study.

Smear Clear had displaced more calcium from the root canal while comparing other

root canal irrigants.

2% CHX expressed the least calcium displacement.

Summary

31

SUMMARY

An In vitro study was done to compare the decalcification effects of 4 different root canal

irrigants.

For determining the decalcification, 50 single rooted mandibular first premolars were

randomly divided into 5 groups, consisting of 10 in each group (Group1. 37% Phosphoric

Acid, Group2.SmearClear, Group3.QMix, Group4.MTAD, Group5. 2%CHX). All the

collected teeth had been cleaned, split into two equal halves and pulp tissues were removed.

Root surface were then covered with cyanoacrylate glue except root canal lumen. Test

solutions were prepared of 10ml of each irrigants and grouped. (n=10). Tooth were divided

equally and placed into sample solution and placed it over the magnetic stirrer for 5 minutes.

0.1 ml solution was taken from each group and aspirated into flame phtometer for the

analysis of the displaced calcium.

Results showed that the highest Calcium displaced from the radicular dentin from a given

time of 5 minutes was Group2, followed by Group 4 and 3. Group 5 exhibited the least

calcium displacement.

References

33

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Consent form

36

CONSENT FORM

Since it is an in-vitro study informed consent is not applicable.

Proforma

38

PROFORMA

GROUPS

AMOUNT OF CALCIUM

DISPLACED( IN PPM)

CONTROL GROUP ( 37 %

PHOSPHORIC ACID)

GROUP 1 ( SMEAR CLEAR)

GROUP 2 (Qmix)

GROUP 3 (MTAD)

GROUP 4 (2 %CHX)

Annexure

40

ANNEXURE

Fig 1: Sectioned samples for MTAD group

Fig 2: Sectioned samples for QMix group.

Annexure

41

Fig 3: Sectioned samples for SmearClear group

Fig 4: Sectioned samples for Control group.

Fig 5: Sectioned samples for 2%CHX group

Annexure

42

Fig 6: Root canal irrigation solutions

Annexure

43

Fig 7: Samples placed in Electromagnet stirrer

Fig 8: Flame Photometer