Effect of Different Irrigation Methods on Phantom Tissue Dissolution in Simulated Lateral Canals

Objectives: Introducing an in vitro method to compare phantom pulp tissue dissolution in endo block lateral canals using syringe irrigation, sonic and ultrasonic activation.
Methods: A 9% gelatin/5% bovine serum albumin (BSA) tissue standard was developed to mimic pulp tissue and provide identical dissolution properties. 0.01% fluorescent dye (methylene blue) was added to the phantom with no effect on the material dissolution. The gelatin/BSA/methylene blue phantom was injected into a resin endo block with a main canal and lateral canals to show the tissue mimic under a fluorescent microscope. Afterwards, the endo block was instrumented with rotary files (MAF=35,04) and then irrigated with three different methods (n = 10); i: conventional needle (gauge=27) irrigation with 5.25% NaOCI, ii: Ultrasonic activation with EndoUltra, and iii: Sonic iactivation with EndoActivator. At last, the remaining tissue in the apical lateral canal (3 mm from the apex) was observed under the fluorescent microscope. The obtained images were analyzed using the ImageJ software. The amount of remaining tissue (%) was compared between groups by t-test statistical analysis.

Results: Statistically higher dissolution rate was showed in irrigated endo blocks with EndoUltra (61.89%±11.57%) in comparison with other methods (needle irrigation = 89.54%±6.71% and EndoActivator = 71.61%±6.18%).

Conclusions: Solution activation increased the tissue-dissolving activity of NaOCl in the lateral canals. Ultrasonic activation showed the superior canal cleanliness ability among the groups.