An earlier study showed that some of the variation in appearance of defects of enamel in sheep incisor teeth induced by trauma during tooth development was related to the phase of activity of the ameloblasts at the time of injury. In the present study, sixteen selected defects were examined by microhardness and microradiography. It was found that in some of the fully formed teeth, the defects had retained the pattern of mineralization present at the time of trauma, i.e., mineralization had ceased. In other teeth, further mineralization of the defects occurred after trauma, resulting in well-mineralized enamel, although sometimes of incomplete thickness. It was concluded that the trauma, depending on its severity, leads to either permanent or temporary dysfunction of the ameloblasts, which also influences the appearance of the resulting lesions.