Mahdi Kadkhodazadeh, Fatemeh Mollaverdi, Zeinab Talei, Maryam Mesbahi, Comparision of Root Canal System Configuration in Primery Teeth, Research Journal of Biological Sciences, Volume 5,Issue 7, 2010, Pages 488-491, ISSN 1815-8846, rjbsci.2010.488.491, (https://makhillpublications.co/view-article.php?doi=rjbsci.2010.488.491) Abstract: The aim of this study was to evaluate the root canal system of primary incisors and molars to do the best pulpectomy. About 80 primary teeth were divided equally into 8 groups after cleaning the teeth and access cavity preparation, Indian ink was injected in all of the root canals. Teeth were placed in HCl 7% for decalcification, Ethyl alcohol for dehydration and methylsalicylate solution for transparentation. All of the teeth were examined by 2 manners: naked eye and using stereomicroscope 10x. Significant difference was found between prevalence of lateral canals in molars with prevalence in incisors and canines. Prevalence of lateral canals was more in lower molar than upper's. Fusion of DB and P roots was more significantly found in the 1st upper molars than 2nd upper molars. Roots with 2 or more canals were more prevalent in lower molars than upper's. So, root canal system of primary molars was more complex than that of primary incisors. The presence of the roots containing 2 or more canals is considerably more probable in mandibular molars than in maxillary molars. Keywords: pulpectomy;primary teeth;incisors;Root canal;methylsalicylate