Comparison of effectiveness of three different irrigation systems in removal of intracanal calcium hydroxide by clearing teeth technique. an invitro study

Introduction: Calcium hydroxide [Ca(OH)2] paste is generally used as intra canal medicament for several weeks. It must be completely removed prior to final obturation, if not Ca(OH)2 residues can affect the quality of root canal obturation by reducing the sealing ability of endodontic sealers, increases apical leakage, results in resorption etc. Various irrigation protocols are employed for effective removal of Ca(OH)2. Materials and methods: 30 freshly extracted single rooted human maxillary anterior teeth were selected. The root canals were then instrumented with ProTaper rotary files up to a size of F3 ProTaper. Between each rotary file, canals were irrigated with 3ml of 3% NaOCl and then rinsed with 17% EDTA for 60 seconds. After instrumentation, aqueous radiopaque Ca(OH)2 paste (CAL-EXCEL) was mixed with a drop of India ink and introduced into all the root canals using lentulo spiral and stored for 1 week. Later Ca(OH)2 paste was removed using conventional irrigation (Needle), ultrasonic irrigation (Piezoelectric) and sonic irrigation (Endoactivator) techniques. After irrigation access cavities were filled with glass ionomer cement and then subjected to clearing technique making them transparent to visualize the internal anatomy of the root canals. The cleared teeth were then observed under stereomicroscope for remnants of India ink stained calcium hydroxide
Results: All the analysis were done using SPSS version 18. Comparison of amount of calcium hydroxide remaining among the study groups was done using Mann-Whitney U test and Kruskal-Wallis tests. Statistically significant differences were found between conventional versus ultrasonic (P<0.01) and conventional versus sonic irrigation (P<0.05). There was no statistical significant difference between ultrasonic and sonic irrigation.
Conclusion: Ultrasonic irrigation technique was better able to remove Ca(OH)2
from the root canal as compared to sonic irrigation and conventional needle
irrigation technique. Conventional needle irrigation had least ability to remove Ca (OH)2 from the root canal.