Figure 6: Panoramic radiographs showing growth changes of the dental germ: case  2. The formation stages of the impacted permanent tooth were approximately (a) Ri at age of 9 years and 2 months, (b) R1/2 at age of 11 years and 0 months, and (c) R3/4 at age of 12 years and 6 months. (d) At age of 16 years and 7 months, most of the tooth crown of the second permanent premolar had erupted, but the second primary molar remained impacted.