Efficacy of MTAD with shortened irrigation time on smear layer removal after rotary canal instrumentation: An in vitro study

Context: A search in the endodontic literature showed the absence of any reports regarding the use of a mixture of tetracycline, acid, and detergent (MTAD) to remove smear layer at shortened irrigation time. Aims: To determine the efficacy of MTAD with shortened irrigation time on smear layer removal after Pro Taper rotary canal instrumentation. Methods: Twenty single-rooted lower premolar teeth were randomly divided into two experimental groups. After decoronation of all the samples, working length was determined and all the teeth were instrumented to master apical size # 30 (F3), using Pro Taper rotary files. Teeth were irrigated with 3% NaOCl during instrumentation. Experimental groups one and two were irrigated with a 5 ml final rinse using MTAD for 5 min and 2.5 min, respectively. After irrigation, all root canals were dried with absorbent paper points. The teeth were then sectioned longitudinally and prepared for a scanning electron microscopic examination. The scanning electron microscope photographs were evaluated using a standard scoring system developed by Rome et al. Statistical Analysis Used: Results were statistically analyzed using Mann–Whitney U-test. Results: When intercomparison was made between Group 1 and 2 at the coronal and middle third, statistically significant difference was observed, with Group 1 having significantly less smear layer than Group 2. In apical third, no statistically significant difference was observed between Group 1 and 2, even though smear layer removal was more in Group 1 than Group 2. Conclusion: Effective smear layer removal was not possible with shortened irrigation time using MTAD