Investigation of maxillofacial morphology and dental development in hemifacial microsomia.

Objective : Hemifacial microsomia (HFM) is a congenital anomaly characterized by unilateral underdevelopment of the mandible and ear. This study was conducted to characterize maxillofacial morphology and dental development in Japanese patients with HFM. Design : This is a retrospective hospital-based study. Patients : The subject population comprised 12 boys and 12 girls (average age, 9.3 years) diagnosed with HFM. Main Outcome Measures : We used posteroanterior (PA) and lateral cephalograms obtained at the first visit to analyze maxillofacial morphology and orthopantomograms to compare dental development between the affected and unaffected sides. Dental development was graded according to Nolla's stages of tooth calcification. Results : PA cephalogram analysis showed that the occlusal plane inclined upward on the affected side in each patient. The mandibular body and ramus were smaller on the affected side than on the unaffected side. Lateral cephalogram analysis showed that the patients tended to have steep mandibles, large gonial angles, and a slightly convex facial structure. The affected side/unaffected side ratio of the mandibular body and ramus correlated with SNB, ANB, convexity, and mandibular plane. The difference in dental development between the affected and unaffected sides was significant at the mandibular molars and the mandibular canine. Conclusions : This study demonstrates a correlation between lateral and frontal measurement parameters in patients with HFM. The data also showed delayed calcification in the mandibular molars on the affected side.

Three-Dimensional Comparison in Palatal Forms Between Modified Presurgical Nasoalveolar Molding Plate and Hotz's Plate Applied to the Infants With Unilateral Cleft Lip and Palate.

The presurgical nasoalveolar molding plate appliance with stent (PNAM) extended from the palatal molding plate; to correct the nostril shape of infants with cleft lip and palate is well known. The PNAM appliance is based on the finding that a high degree of plasticity is maintained in the cartilage of infants during the first 6 weeks after birth. However, on the current PNAM protocol described by Grayson et al. the nasal stent is supposed to be an adjunct to the palatal molding plate after reducing the severity of the alveolar cleft width. We have used the modified Hotz's plate from the setup model and built up the nasal stent even before reducing the severity of the alveolar deformity. In this study we assess the effects of the modified Hotz's plate and the modified PNAM appliance for the alveolar and palatal form. The lateral deviation of the incisal point, the width of the palatal cleft, and the degree of curvature of the palatal vault were first evaluated on plaster models. The PNAM group is smaller on the lateral deviation of the incisal point than the modified Hotz's group. The decreased average width of the palatal cleft and curvature of the palate, was almost the same in both the modified Hotz's and PNAM groups. In comparison with the modified Hotz's plate, the modified PNAM appliance also improves the molding of the alveolar segments and reduces cleft width.

Management of developmental enamel defects in the primary dentition.

This study attempted to identify appropriate materials for restoration of enamel defects in the primary dentition, which were classified by severity and region with the modified developmental defects of enamel index. To identify the most appropriate materials, we used restorative materials to protect teeth and evaluated clinical outcomes of restoration. Three materials were used for restoration or repair after dislodgement of restorations. Our findings in this case suggest that, because of its durability and esthetic advantages, adhesive resin is beneficial for patients with enamel defects, particularly for restorations of less than two-thirds of the extent of the defect.

The induction of enamel and dentin complexes by subcutaneous implantation of reconstructed human and murine tooth germ elements.

Tooth induction by xenogenic graft of reconstructed human tooth germ components has never been attempted. Here we report our first attempt at a transplantation of human tooth germ components, heterologously recombined with mouse dental epithelia, into immunocompromised animals. Human third molar tooth germs enucleated from young patients as prophylactic treatment for orthodontic reasons were collected. The whole or minced human dental papilla was reconstructed with human- or mouse molar enamel epithelium, and transplanted in the dorsal aspect of C.B-17/Icr-scid Jcl mice. The transplant of human dental papilla reconstructed with human enamel epithelium formed thin dentin and immature enamel layers by 3 to 4 weeks, but remained extremely small in quantity due to a shortage of epithelial components in the graft. The addition of E16 mouse molar enamel organs (n=10-12) to each graft augmented the formation of tooth germ-like structures, but the differentiation of mouse molar ameloblasts was suppressed. However, once a solid layer of mineralized dentin was established, mouse ameloblasts accelerated their differentiation, and completed the enamel matrix formation and maturation within the following 4 weeks, whereas human ameloblasts, which had interacted with human dental papilla, remained in the stage of matrix formation during the same period. These data imply that, in reconstructed transplants, the differentiation of mouse dental epithelia is restrained by putative suppressive factors derived from human dental papilla until they are separated by mineralized dentin layers that serve as a diffusion barrier. The mouse enamel organ nevertheless retains its own phenotypic characteristics and intrinsic timing of cell differentiation and function.