ABSTRACT

Background: Ultrasonic irrigation has been proved for itsremarkable cleaning efficiency in the field of endodontics. Butits role in endodontic re-treatment has been understated. Thereis not much data available to understand the effect of ultrasonicirrigation for the evaluation of cleanliness of dentinal tubuleswhen it is used with or without chloroform, a gutta perchasolvent during endodontic retreatment

Aim: To compare the influence of ultrasonic irrigation withsyringe irrigation on cleanliness of dentinal tubules after guttaperch removal for endodontic retreatment with or withoutthe use of chloroform a gutta percha solvent using scanningelectron microscope (SEM).

Materials and Methods: Freshly extracted 45 humanmandibular premolar teeth for periodontal and orthodonticreasons were taken and were occlusally adjusted to a workinglength of 19 mm. The root canals of all teeth were preparedchemo mechanically to a master apical file size 40 and weredivided in various groups. In Group 1 (n=5; control group), thecanals remained unfilled. In Groups 2 and 3 (n=20 each), thecanals were filled using lateral compaction with gutta-perchaand AH plus sealer, removal of root fillings was undertaken after2 weeks using Gates Glidden drills and H files without chloroformin Group 2 and with chloroform in group 3. The specimen ofGroup 2 and 3 were further divided into two subgroups I and II (n=10). In subgroup I, irrigation was done using side ventedneedles and sodium hypochlorite. In subgroup II irrigationwas done using passive ultrasonic irrigation with sodiumhypochlorite. Thereafter, the roots were split and the sectionswere observed under SEM. The number of occluded dentinaltubules /total number of dentinal tubules were calculated forthe coronal, middle and apical third of each root half. Statisticalanalysis was performed using one-way ANOVA followed byTukey’s test using standardized technique.

Result: Results indicated that the cleanest dentinal tubuleswere found in the control group (Group 1 where the canals wereunfilled) followed by the non chloroform group with ultrasonicirrigation (Group 3 subdivision II) followed by chloroform groupwith ultrasonic irrigation (Group 2 subdivision II), the nonchloroform group with syringe irrigation (Group 3 subdivisionI) and least cleanliness was found in the chloroform group withsyringe irrigation (Group 2 subdivision I).

Conclusion: Under the limitations of this study it could beconcluded that both ultrasonic and syringe irrigation showedcleaner canals when chloroform was not used. Irrigation whendone with ultrasonics leads to cleaner tubules than syringeirrigation. Hence, mechanical methods of retrieval in conjunctionwith use of passive ultrasonic irrigation should be a part ofretreatment protocol.

Keywords: AH Plus, Passive ultrasonic irrigation

INTRODUCTION

Even after practicing endodontic protocol for centuries, cent percentsuccess seems like a mirage, a 14-18% of failure has been observed[1]. There is an increasing demand to preserve teeth, and a growinginterest in conventional retreatment. This procedure requiresthe removal of the existing obturation, further instrumentation,disinfection and re-obturation [2]. Removing the maximum amountof obturating material from inadequately prepared and/or obturatedroot canal system appears to be essential in order to uncoverremaining necrotic tissue or bacteria that may be responsible forthe persistent disease and enable thorough chemomechanical reinstrumentation and disinfection of the root canal system [1,3,4].

One of the various techniques for facilitating removal of oldendodontic obturation, is chemical dissolution of gutta perchausing gutta percha solvents. Chloroform, eucalyptol, orange oil,halothane are some of the examples of gutta percha solvents. Thereis not much literature available for evaluating the role of solventsin cleanliness of dentinal tubules after retreatment using SEM.Horvarth et al., concluded that solvents led to more gutta perchaand sealer on root canal walls and inside dentinal tubules [2]. It wasproposed that further studies should evaluate the effect of ultrasonic irrigation on the cleanliness of dentinal tubules during endodonticretreatment. Till now, the effect of ultrasonic irrigation alone and incombination with chloroform has not been assessed for evaluatingcleanliness of dentinal tubules using scanning electron microscope(SEM). Hence, an in vitro study was framed to evaluate the dentinaltubules visually by SEM if root filling material remained in dentinaltubules after gutta percha removal was done with and without usingchloroform and ultrasonic irrigation.