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Potential of Trichloroacetic Acid in Smear Layer and Calcium Hydroxide Removal in Root Canals-Exploratory Pilot
Eulogio Munoz1, Andrew B Benbow1, Jon-Brighton C Russell1
1Department of Endodontics, College of Dentistry, University of Tennessee Health Science Center, Memphis, Tennessee, USA.
Introduction And Aims:
This study investigated whether trichloroacetic acid (TCA) can function as an adjuvant solution to facilitate pulp dissolution and removal of smear layer and calcium hydroxide (Ca(OH)2) during endodontic procedures.
Methods:
For pulp dissolution studies, fresh pulp was weighed before and after immersion in 90% TCA and/or 6% NaOCl. For smear layer or Ca(OH)2 removal, each study utilized 25 extracted human teeth with prepared root canal systems. For Ca(OH)2 removal, canals were filled with Ca(OH)2 and stored at 37 °C for 14 days. Teeth were divided into five groups (n=5/group) and the canal irrigated with various solutions. Group I: saline; Group II: 17% EDTA; Group III-V: 90% TCA for 15, 30 or 60 seconds, respectively. Samples were subjected to scanning electron microscopy (SEM) or spectrum analysis.
Results:
Under our experimental conditions, NaOCl alone consistently dissolved more pulp than TCA at all time points (1, 3, and 5 minutes) under static conditions at RT (P < .01 or < .001). Some TCA groups had significantly less smear layer than the saline or EDTA group in the coronal and middle thirds (P < .05 to < .001). In the apical third, there was significantly less smear layer in the TCA 15-second group than the control or EDTA group (P < .01 or P < .001). In Ca(OH)2 removal studies, the coronal third showed that TCA 30-second group and middle third TCA 60-second group had significantly less Ca(OH)2 than the EDTA group (P < .05).
Conclusion:
These findings warrant further studies with a larger sample size to validate the potential use of TCA as an adjunctive agent to facilitate smear layer and Ca(OH)₂ removal from root canal walls, CLINICAL RELEVANCE: This is the first study to evaluate whether TCA can be used as an adjunctive endodontic irrigant. Our findings suggest that a brief treatment with TCA is more effective than EDTA for canal smear layer removal and may facilitate Ca(OH) 2 removal.
