• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.2
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• pp.139-145
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• 2002

In a primary teeth, dental caries is rapidly advanced the pulp disease, because the primary teeth have the thinner and the weaker enamel layer and the wider pulp chamber than relatively the permanent teeth. And the pulps of primary teeth are exposed during caries removal or even they are exposed by unexpected movement of the children or by trauma. For successive pulp treatment in primary teeth, it is necessary to understand completely about multiple canal morphology, variation of root canal anatomy and specific problem related to root formation and resorption of primary teeth. In upper primary molar, canal configuration of mesial root has the most variation same as upper molar. If not canal treatment is completely, most of all endodontic treatment should be failed. In a clinical case report, upper primary molars existed persistent pain or bleeding during treatment were founded the second MB canal and were performed the endodontic treatment of theirs. As a result, the upper primary molars have no symptom and good prognosis. In the examination of extracted upper primary molar, we found that 8 of 35 teeth(22.8%) in the upper primary first molars and 22 of 33 teeth(66.6%) in the upper primary second molar had the second mesiobuccal canal. It has revealed the high prevalence of two canals in mesiobuccal roots of upper primary molars. The frequency of occurrence of the second mesiobuccal canal must be taken into consideration when endodontic treatment is planned and as a possible cause of otherwise un explained failure.