The cervical defect (CD), the so-called wedge-shaped defect in Japan, or the non-carious cervical tooth lesion of human permanent teeth may be eroded by cross tooth-brushing with and without occlusal stress, or by attachment of dental clasp for a long time. Such a CD occasionally causes dentin hypersensitivity although the reparative dentin (RD) is deposited towards the dental pulp cavity. However, the correlation of a CD and the RD in volume has not been elucidated yet except for the difference of their areas on the ground sections reported previously. In this study, we analyzed the area and volume correlations of a CD and the RD in each teeth (n=10) by micro CT analysis. The area ratio (RD/CD) was 72.4±28.6 % (r=0.856, p<0.01) on the longitudinal cut plane showing the maximum areas of a CD and the RD, which were similar to those of the ground section assumed longitudinal central line of a tooth. On the other hand, the volume ratio (RD/CD) was 18.0±8.2 % (r=0.792, p<0.01). Therefore, it is clearly illustrated by micro CT analysis that the volume ratio (RD/CD) should be extremely lower than the area ratio in the longitudinal X-ray slices and also the ground sections previously reported. As the clinical consideration, the RD formation will be alleviated dentin hypersensitivity. On the basic observations, it was accuracy illustrated that micro CT analysis was useful for the volume measurement of the RD as well as the CD.
We report here a case of skeletal Class III malocclusion with mandibular prognathism treated with a combination of orthodontic and orthognathic surgery. A 28-year-old woman presented with a cross bite and the inability to incise food; she had no history of trauma or serious illness. She was diagnosed with a skeletal Class III malocclusion and crowded teeth. The left mandibular first molar showing an inappropriate root canal treatment was extracted and the left mandibular third molar was implanted into the first molar extraction space. She was treated with conventional fixed edgewise appliance therapy combined with orthognathic surgery (sagittal split ramus osteotomy). The mandibular prognathism was eliminated. The transplanted tooth remains stable more than 5 years after the procedure.