Yasutaka Kaihara

Management of intruded primary teeth after traumatic injuries

Intrusions occur frequently in the primary dentition. It has been reported that conservative treatment of the intruded primary tooth is preferred if the apex is away from the permanent tooth germ. Conservative treatments include waiting for spontaneous re-eruption, and surgical re-positioning and fixation. Few papers have been published in Japan comparing the prognoses of intruded primary teeth between these two different modes of treatment. Therefore, optimal treatment for intruded primary teeth has been a topic of controversy among clinicians. The aim of this study was to compare the outcomes of intruded primary teeth between these two modes of treatment. Moreover, we examined the issue of treatment of choice for intruded primary teeth. The subjects consisted of 17 children referred to the Hiroshima University Hospital Department of Pediatric Dentistry for the treatment of 21 intruded primary teeth. Fourteen teeth were allowed to spontaneously re-erupt (group W), and 7 teeth were repositioned and fixed (group R). Antibiotic therapy and irrigation were performed in all intruded teeth. Treatment outcomes were evaluated using the following parameters: re-eruption, pathological pulp changes, increased mobility, discoloration, pulp canal obliteration, pathological root resorption, and disturbances of permanent teeth. In group W, root canal treatment or extraction were not performed since re-erupted teeth reveal no signs of infection. On the other hand, in group R, 57% of teeth required endodontic treatment or extracted due to signs of infection. The result showed treatment outcomes in group R were worse than those in group W. Our study indicates that most intruded primary teeth re-erupt with a favorable prognosis. Therefore, observation with irrigation and antibiotic therapy should be the treatment of first choice.

Three-dimensional analysis of the effects of the treatment on anterior crossbite in the primary dentition

We performed measurement using a 3-dimensional measurement system in study models of children with anterior crossbite in the primary dentition treated using a chin cap and lingual arch, and evaluated changes in the dentition and occlusion after treatment based on measurement values and also using wire frame models. Comparing with the situation before treatment, the overbite of anterior teeth shows improvement to become shallow and the terminal plane becomes vertical type and the occlusal plane becomes flatter. Labioclination of upper anterior teeth, linguoclination of lower anterior teeth and backward movement of lower dentition are observed. Occlusal view shows that both upper and lower dental arch become semicircular configuration. The width, depth and height of the post-treatment dentition became closer to the standard values. Chin cap and lingual arch treatment for anterior crossbite during early childhood is effective, and also helpful in the normal development of occlusion in children.