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1122 JIDA, Vol. 5, No. 11, November 2011

INTRODUCTION

The complete root canal morphology has alwaysdaunted the genius of the researcher, teacher &clinician. To study, evaluate & research it in Vitro.Methods like Vertical and Longitudinal sectioning,1andSEM studies have been tried out however, each have

their own shortcomings.Hence a technique called The Clearing Technique2,3

was modified and after some changes tried and carriedout successfully.

AIMThe objective of this study was three-dimensional

continuous view of the root canal system.

MATERIAL AND METHODS27 extracted teeth were chosen randomly. Some of

them were already root canal treated but extracted dueto complications or failures or patients reluctance for reroot canal treatment. Some had been extracted due toperiodontal reasons or the patient was going in for acomplete denture, a few were third molar etc.

Technique: A simple inexpensive procedureconsisting of decalcification, dehydration and clearingwas done.

Teeth that were already root canal treated wereimmersed in pelican ink for 48 hours after removing thecoronal restoration to evaluate for microleakage. Teethwhose pulpal anatomy was to be studied were injectedwith the same ink after coronal access preparation. Insome of the teeth the coronal part of the tooth that wasnot to be made transparent was coated with sticky wax.

Decalcification: The teeth were placed in 5% Nitricacid at room temperature, which was changed daily &manually agitated 3 times. Depending on the size of thespecimen, they were placed for 48 to 72 hours duration.

The end point of decalcification was assured by theneedle method, which was inserted in an unimportantpart of the tooth.

This was followed by a 4 hour running water wash toremove all traces of the acid.

Dehydration: Was done in a series of Ethyl alcoholrinses

1. 80% Ethyl alcohol overnight followed by

2. 90% Ethyl alcohol for 3 hours and finally

3. 100% Ethyl alcohol four rinses of 1 hour each.

Clearing: The dehydrated teeth were placed in methylsalicylate for 24 hours that rendered them transparent.

Preservation of the specimen: The cleared specimensmay be stored and displayed in their final clearing agentsor permanent mounting in clear plastic too can be done.

RESULTSThe tooth can be rendered transparent in Vitro by a

Clearing Technique and its Potential Applications -An In Vitro Study

Meenakshi Verma*

Abstract

Objective : Sectioning, SEM studies and various different methods have been tried out for In Vitro visualizationof the complex root canal morphology, but each have their own limitations. A different technique namely thetransparent tooth system or the clearing technique was modified and tried out.

Material & Methods : 27 teeth extracted for various reasons were randomly selected and were subjected to theprocess of decalcification, dehydration & clearing, which rendered them transparent. These teeth were thenstudied for their morphology, micro-leakage, broken instrument etc.

Results : The tooth can be rendered transparent in Vitro by a relatively easy & inexpensive method. This canbe put to many uses like studying the pulpal anatomy, micro leakage studies, analysis of broken instrumentsand perforations, homogeneity and adaptation of Guttapercha, etc.

Conclusion: The clearing technique allows three dimensional study of the root canal system with a plethoraof applications and advantages.

Key Words : Clearing technique, Transparent tooth, Three dimensional visualization, Canning electronmicroscope.

*Reader, Department of Conservative Dentistry andEndodontia, Bharati Vidyapeeth Dental College & Hospital,Navi Mumbai.

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relatively easy & inexpensive method. This can be put tomany uses like studying the pulpal anatomy, microleakage studies, analysis of broken instruments and

perforations, homogeneity and adaptation ofGuttapercha, etc (Figs. 1-5).

DISCUSSIONThe study of the complex root canal morphology is

very important and various techniques have beenadvocated. Vertical sectioning can be done but this doesnot allow a continuous view of the entire root canalsystem. Longitudinal sectioning compensates for it buta three dimensional picture is not possible.1 SEM studiestoo have a major disadvantage of limited area available.

Till 1982 the Clearing procedure was used foranatomical studies of the pulp cavity2. In 1983 Tagger M

etal put forward an improved method with methylsalicylate as the clearing agent for three dimensionalstudy on apical leakage.4

The clearing technique or transparent root canal

a) Makes three dimensional assessments possible5.

b) Maintains the original form of the root canal even toits minute detail.6

c) Failure in preparation of the specimen is rare.

d) Specimen can be preserved for a long time.

Hence this technique has numerous uses andadvantages.

1. Can be used as an important teaching and todemonstrate the Pulpal Vascular System.6,7

2. Can be used for better understanding andappreciation of Instrumentation.

3. Can be used as an important research tool forinvestigation of micro leakage studies.4

4. In addition to micro leakage, this technique can beused to study, distribution of sealer, fillingmorphology extent, homogeneity and adaptation ofGuttapercha.8

5. Can provide an insight for analysis of clinical

failures such as broken instruments andperforations.

SUMMARY AND CONCLUSIONSThe methodology of rendering teeth transparent in

vitro was studied.

27 teeth extracted for various reasons were randomlyselected and were subjected to the process ofdecalcification, dehydration & clearing, which renderedthem transparent. These teeth were then studied for theirmorphology, micro-leakage, broken instrument etc. Theresults showed that the Clearing technique is a relativelyeasy technique to obtain a three dimensional continuousview of the root canal system3.

From this study it is also evident that the transparentmodel system has a number of possible applications2

limited only by imagination.

We hope this technique will benefit the student whoin due course will become a good researcher or a clinicianwhich will ultimately lead to improved Endodontics.

REFERENCES1 . Weine F.S , et al. Canal configuration in mesio-buccal root of

maxillary first molar and its endodontic significance. OSOM OP 1969; 28(3) : 419-25.

2. Tagger Micheal. Clearing of teeth for study and demonstrationof pulp. J Dent Edn 1976; 40 (3) : 172-4.

3 . Robertson D, et al. A clearing technique for the study of root

canal system. J Endo 1980; 5 (2) : 421-24.4 . Tagger M, et al. An improved method of three-dimensionalstudy of apical leakage. Quintessence Int 1983; 10 : 981-6.

5. Robertson DC, Leeb IJ. Evaluation of transparent tooth modelsystem T. M. for evaluation of Endodontically filled tooth. JEndo 1982; 8(7) : 317-21.

6 . Al Shalabi RM, et al. Root canal anatomy of maxillary firstand second permanent molars. Int Endod J 2000; 33 : 405-14.

7 . Blaine M Cleghorn, et al. Root and root canal morphology ofpermanent maxillary first molars A literature review.J Endod2006; 32 : 813-21.

8. Evans John, Simon J. Apical Seal produced by injectablethermoplasticised gutta-percha in the absence of a smearlayer and root canal sealer. J Endo 1986; 12(3) : 101-7.

Fig. 1 : Unpredictable RadicularAnatomy and purpal vascularsystem of a lower third molar.

Fig. 2 : Fractured file in alower mandibular molar.

Fig. 4 : Microleakage seenin the form of dye

penetration around the GPpoint in a mandibularanterior due to loss of

coronal seal.

Fig. 5 : Perforationin a mandibular

second molar.

Fig. 3 : Maxillary caninethat had been RC treatedby conventional method.

Each GP point can be seenclearly.