Evaluation of Chitosan as Irrigating Solution for Pulpectomy in Non-Vital Primary Teeth

45 teeth will be sub-divided at random with a computerized method, according to the type irrigant and duration of its application into 3 groups (15 teeth in each group): Group1(control group): The teeth will be irrigated by 2 ml 1% NaOCl after each file. Group2: The teeth will be irrigated by 2 ml 1% NaOCl after each file then with 5 ml of 0.2% chitosan for one minute. Group 3: The teeth will be irrigated by 2 ml 1% NaOCl after each file then with 5 ml of 0.2% chitosan for 3 minutes. Evaluation Clinical evaluation will be done for all groups at one, three, six and 12 months. The following parameters will be evaluated: Pain (spontaneous pain and pain with percussion) Degree of mobility Resolution of signs of infection (fistula) at the mucobuccal fold. Radiographical evaluation will be performed to each patient immediately after the final restoration and three, six and 12 months postoperatively. The decrease of radiolucency and the presence of internal or external root resorption will be evaluated. Bacteriology : The microbiological evaluation will be done at the Biotechnology Research Institute - Suez Canal University. PCR will be used for detection of Enterococcus faecalis. Microbiological investigation will be used for counting the number of Enterococcus faecalis.