Abstract
In order to asses histopathologically the changes that occur when teeth that have fallen out are replanted in the cavity wall of alveolar sockets damaged by trauma, we used the immature second maxillary incisors of dogs, and after they had fallen out, subjected the alveolar bone proper of the cavity wall of the alveolar socket to mild and severe damage, and conducted a replantation experiment. We prepared undecalcified standard horizontal continual ground sections and made comparative observations using microradiograhy, fluorescence microscopy, and polarization microscopy, and also included stanardized roentgeography and clinical findings.
1) When there was mild damage to the tooth, superfical resorption was observed in a portion of the root, and cement fomation was noted around the entire cicumference of the root. Inflammatory resorption and osseous ankylosis were observed in severely damaged teeth, and cement formation was irregular.
2) Extensive regeneration of tha periodontal ligaments was observed in mildly damaged teeth, but only a slight degree of periodontal ligament regeneration was detected in severely damaged teeth.
3) When we examind the periodontal ligament space around the replanted teeth in the horizontal sections, we found that it was of nearly uninform width in the mildly damaged teeth, but that its width had become irregular in the severely damaged teeth, and that its width had become slightly narrower.
4) Examination of the periodontal ligament space along the axis of the tooth showed that it was in the form of a functional hourglass in tha mildly damaged teeth, but that its width had become irregular in the severely damaged teeth and its functional shape had lost.
5) New laminar bone fotmation was observed in the perialveoar bone in mildly damaged teeth, but bony trabeculae had intermingled in the severely damaged teeth and had formed irregulaly.
6) Assessment of root formation revealed no abnormalities in the amount of root formation in the mildly damaged teeth, whereas root shortening and infraversion were noted in the severely damaged teeth.
