A number of the bizarre and unusual anormalies in human teeth becomes evident during the childhood years. While teeth usually erupt synmetrically at certain times, it is often found that in spite of the eruption of a tooth on one side. The tooth on the other side does not erupt and moreover is found to be transposited or rotated. If teeth are not erupted or delayed in erupting. They become an obstacle not only with respect to occlusal function but also esthetically. In the case examined it was found by X-ray examination that the mandibular second molar inclined mesially during the eruption period, and absorbed the distal root at the center of cervical area of the mandibular first molar. On the other hand, the mandibular left second molar was about to erupt, and it appeared normal. There was nothing peculiar about the growth of the patient, and the cause of uneruption of the tooth was not clear. It is suggested that a recall examination must be carried out till the second molars perfectly erupt.