The main goal of endodontic treatment is cleaning and disinfection of the root canal system. (Martins et al., 2016) One of the important causes of the failure in endodontic treatment is the presence of untreated canals. (Song et al., 2011) Identification of variations in the anatomy of the root canal system is a prerequisite for successfully diagnosis and treatment of endodontics. (Martins et al., 2016; Neelakantan et al., 2010) One of the most important anatomical variations is the c -shaped root canal. (Jo et al., 2016) The anatomical complexities of the root canal cause a challenge during endodontic treatment. (Naseri et al., 2013) C-shape teeth treatment is one of the most challenging treatments. (Fernandes et al., 2014) It is due to its unique characteristics and the presence of web and fins connecting the individual root canals to each other, (Jo et al., 2016) which causes difficulty in proper shaping, cleaning and obturation of root canal system. (Kim et al., 2018) The c-shape root canal was first described by Cooke and Cox in 1979. (Cooke and Cox, 1979) This variation is more common in the mandibular second molars (Ladeira et al., 2014; Martins et al., 2016; Zheng et al., 2011) and its occurrence is very rare in the maxilla primary molars. (De Moor, 2002; Cleghorn et al., 2006) The morphological variation of the c-shape root canal is unusual and can lead to problems during treatment. This research has described the successful treatment of two unusual c-shape maxilla primary teeth.
