Evaluation of efficacy of different irrigation techniques in the removal of calcium hydroxide

The aim of study is to compare the removal of calcium hydroxide by the usage of two different irrigation techniques and two different laser (Er:YAG, Er,Cr:YSGG) systems. After root canal preparation with rotary system, each root was split longitudinally through the canal, forming two halves. A standard groove was cut in one canal wall 2–6 mm from the apex, to simulate the irregularities in root canal system. After each groove was filled with calcium hydroxide paste using paper points, the teeth were reassembled with sticky wax and orthodontic latex elastics and the apical foramen was sealed with wax. The teeth were stored for 1 week at 37 ˚C ve % 100 relative humidity to simulate the clinical situation when Ca(OH)2 is used as an canal dressing between two treatment visits. Ca(OH)2 was removed with syringe irrigation by using 10 ml % 5 NaOCl and 10 ml % 17 EDTA, respectively. 4 groups were created. Group 1 (n= 10) was chosen as control group. In group 2, % 5 NaOCl within the root canals were activated by performing Er: YAG laser with a plain fiber tip (Preciso 300/14, Fotona). In group 3 (n= 10), % 5 NaOCl within the root canals were activated by using Er: Cr: YSGG laser with 21mm fiber optic RFT2 tip. In Group 4 (n= 10), the teeth were ultrasonically irrigated using % 2.5 NaOCl as the irrigant. After that, all teeth were irrigated with 10 ml distilled water as final irrigation. The root halves were separated again. The grooves were examined under the stereo microscope under x20 magnification and scored. The results were statistically analyzed by using 3-way ANOVA and Tukey tests. Ca(OH)2 residues were observed in all groups. No significant difference was found between Group 2, 3 and 4.