七條 なつ子

Background: Melanotic neuroectodermal tumor of infancy (MNTI) is a very rare tumor, and case reports of orthodontic treatment for patients with MNTI may be previously unreported. This article describes the orthodontic treatment for a 7-year-old girl with MNTI in the mandible. Case: Her chief complaint was anterior crossbite. Although she had an MNTI diagnosis at the age of 8 months, it remained subclinical. Therefore, she has been regularly followed-up by computed tomography (CT) and magnetic resonance (MR) imaging without aggressive treatment. We had worried about the stimulation of MNTI on the mandible by changing her occlusal position with orthodontic treatment. Therefore, we sufficiently explained to her and her family that orthodontic treatment was at risk for worsening MNTI. However, they desired treatment that consisted of maxillary protraction and slow expansion to correct anterior crossbite and encourage the permanent tooth eruption. After 19 months of active orthodontic treatment, the anterior crossbite was improved, and the eruption of permanent teeth made good progress. No evidence of progression and exacerbation of MNTI has been found by both CT and MR imaging. As the observation period is still short, we need a careful and long-term follow-up of her occlusion and MNTI. Furthermore, when we encounter rare cases without previous experience and reports, informed consent was of particular importance.

BACKGROUND: Open bite is considered one of the most complicated malocclusions in orthodontic treatment. In this study, the authors successfully treated total open bite involved in hypercementosis using orthodontic miniscrews. CASE DESCRIPTION: A woman aged 25 years 8 months had total open bite. Her occlusal contact at the maximum intercuspation was present at the right second molars. A panoramic radiograph showed diffuse hypercementosis. The titanium miniscrews were interradicullay implanted between the first and second molars, and intrusion force was applied for 14 months. After active treatment, the patient's maxillary first molars showed about 1.6-millimeters of intrusion, resulting in counterclockwise mandibular rotation. Her acceptable occlusion was maintained after 1.0-year retention. PRACTICAL IMPLICATIONS: Miniscrews might be useful tool to improve malocclusion involved in diffuse hypercementosis though they are considered to be difficult to move and brought on ankylosis.