Reconstruction images by DentaScan^® to evaluate the jaw bone, which are used for the preoperative examination of dental implantation, show highly accurate information regarding the thickness of the cortical bone in the whole circumference of the mandibular bone, the height and width of the jaw bone, and the course of the inferior alveolar nerve. In this study, to investigate the influence of age and gender in the thickness of the cortical bone and the size of the medullary cavity in the mandibular bone were bone morphometrically analyzed using reconstruction images.
The subjects were 39 patients (50 sides) aged between 40 and 70 years, in whom the teeth posterior to the mandibular second premolar were absent, among patients in whom evaluation of the mandibular bone was performed as the preoperative examination of implantation using panoramic radiography and DentaScan^®. In this study, using slice images of the area 2 cm posterior to the mental foramen, the thickness of the mandibular cortical bone and the width of the medullary cavity were measured, and the changes in the values with age and gender were analyzed. Furthermore, the results were compared with those of the evaluation of bone amount by the conventional panoramic radiography.
As a result, the panoramic radiographical morphometry could not detect the changes in the bone amount in the mandibular bone. However, analysis using reconstruction images by DentaScan^® revealed that the thickness of the cortical bone in the inferior border, and on the central and inferior buccal sides of the female mandibular bone decreased with age. Furthermore, it was speculated that the medullary cavity in the female mandibular bone enlarged with age, by the resorption of the inner surface of the cortical bone.

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To investigate the magnitude and direction of orthodontic force generated by the various arch forms, we proposed the quantitative measurement of orthodontic force by experimental arch model with strain gauges. The comparison of orthodontic force was evaluated with (1) plane arch wire, (2) toe-in bend, (3) tip-back bend, (4) crown lingual torque, and (5) step bend. The size of wires is 016″×016″,016″×022″ and 017″×025″ and made of stainless steel. Furthermore the magnitude of orthodontic force and force/root area ratio was calculated.
From the results, the force magnitude and direction were determined by relation of arch form and placement of neighboring brackets, but the effect of bending wire changed with size of wires. The maximum force/root area ratio of 2026.2 mN/cm². These results suggested that possibility of applying stronger than optimum force, and take notice to select size of wires, in orthodontic practice.

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In hemifacial microsomia (HFM), the major deficiency is seen in the mandible, but other craniofacial bony structures can be involved as well. This study was designed help establish baselines regarding Japanese craniofacial symmetry in the case of HFM symptoms that incorporate the deformity of not just the mandible but also of other craniofacial skeletal features. Six subjects between the age of 7 and 13 years were studied via three-dimensional computed tomography (3DCT) images and their occlusion. The subjects were classified as being of Pruzansky's Type II A, II B, or III. The Mandibular Deformity Scoring System (MDS), the Cranial Deformity Scoring System (CDS), and the Craniofacial Deformity Scoring System (CFDS) developed by Vaandrager are based on 3DCT reconstructions, which suggests that craniofacial morphological characteristics of HFM can be marked as the total score. We investigated the relationship between CFDS, 3D bone structure, and distinctive occlusion on each subject. The result indicated that the influence of dysplasia appeared mostly on the nasomaxillary component and on the corpus length and full length of the mandible. There were only minor differences in the lengths of ramus and lateral cranial base among the types by Pruzansky. The position of the temporomandibular joint was high compared with that of the control side because of nasomaxillary dysplasia. Therefore, regardless of the ramus length, the mandibular midline was shifted to the affected side. In the cranial area, in patients with Pruzansky type II B, the marlar bone, zygomatic arch maxilla part, and temporal part could have a much more severe appearance than in the patient with Pruzansky type II A. The CDS score for patients with Pruzansky type III were very different from patients in the other categories. CDS was conversely related to MDS; the Pruzansky's classification was not directly proportional to the CDS score.

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To investigate the cellular mechanisms of physiological root resorption in human deciduous teeth, the authors examined the immunocytochemical localization of vacuolar-type H⁺-ATPase, a lysosomal cysteine proteinase, cathepsin K, matrix metalloproteinase-9 (MMP-9), and receptor activator of NFKB ligand (RANKL) in odontoclasts. H⁺-ATPase, cathepsin K and MMP-9 are the most important enzymes for decalcification of apatite crystals and degradation of type-I collagen. In addition, RANKL is one of the key regulatory molecules in osteoclast formation and functions. Odontoclasts developed extensive ruffled borders and clear zones apposed to the resorbing root dentine surfaces. On immuno-electron microscopy, the expression of vacuolar-type H⁺-ATPase was detected along the limiting membranes of pale vacuoles and the ruffled border membranes of odontoclasts. Cathepsin K in odontoclasts was localized within pale vacuoles, lysosomes, the extracellular canals of ruffled borders, and the underlying resorbing dentine surfaces. MMP-9 localization in odontoclasts was similar to those of cathepsin K. RANKL was detected in both mononuclear stromal cells and odontoclasts located on resorbing dentine surfaces. These results suggest that (1) odontoclasts are directly involved in decalcification of apatite crystals by active extrusion of proton ions mediated by H⁺-ATPase and (2) extracellular degradation of dentine type-I collagen by both cathepsin K and MMP-9, and (3) odontoclast differentiation and activity are regulated, at least in part, by RANKL, and (4) RANKL is possibly produced by mononuclear stromal cells and odontoclasts themselves in the resorbing tissues. Thus, the cellular mechanisms of physiological root resorption appear to be quite similar to those of osteoclastic bone resorption.

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Receptor activator of NFkB ligand, RANKL, is one of the key regulatory molecules in osteoclast formation and functions. The authors examined the RANKL localization in the periodontal tissues during experimental movement of rat molars. To produce orthodontic force, an elastic band was inserted between the upper first and second molars for 4 days, and the dissected maxillae were subjected to light and electron microscopic immunocytochemical examination for RANKL. Expression of RANKL protein was detected in osteoblasts, osteocytes, fibroblasts, and osteoclasts mostly located in resorption lacunae. In osteoblasts, osteocytes, and fibroblasts, RANKL localization was mainly observed in the cytoplasm, the cisterns of rough-surfaced endoplasmic reticulum and along the plasma membranes. In osteoclasts, RANKL was expressed along the ruffled border membranes and in the cytoplasm including that of the clear zone. These results suggest that during tooth movement, osteoclast differentiation and activation are regulated, at least in part, by RANKL, possibly produced by osteoblasts/stromal cells and osteoclasts themselves in the periodontal tissues.

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The objective of the present study was to compare the changes in the occlusal contact area (OcAr) and the occlusal force (OcFr) longitudinally during retention in patients with various types of malocclusion by the use of pressure-sensitive occlusal sheets (Dental Prescale).
The subjects treated at Showa University Dental Hospital were selected according to the following criteria : 1) clinically normal function of the oral and maxillofacial region; 2) less than 4 mm deviation between the maxillary and mandibular midlines; 3) no congenital craniofacial anomaly such as cleft lip and/or palate; 4) the first and second molars being present and functioning without extensive defects. The subjects were divided into four types : Class I, II, III, and surgical class III (S-Cl. III). All subjects had active treatment completed with or without the extraction of premolars. OcAr and OcFr were recorded by using Dental Prescale at three different (early, middle, late) retention stages.
All types of subjects showed a significant increase in both OcAr and OcFr during retention in female and male. The increasing ratio during retention among four types were ranked in the following order : S-Cl. III>> Cl. I>> Cl. II>> Cl. III in both female and male. Therefore OcAr and OcFr in Cl. III were greater than those in S-Cl. III at an early stage of retention in both female and male. This order was reversed in the late stages of retention. The order of OcAr and OcFr among the four types of malocclusion in female and male were respectively as follows : Cl. I>> Cl. II>>Cl.III≅S-Cl (female); Cl.I≅Cl.III≅S-Cl. III>>Cl. II (male).
These results suggest that OcAr and OcFr obtained from the patients during retention increased time-dependently in female and male. This increase did not depend on the extraction of premolars or on the type of malocclusion.Key words : malocclusion;occlusal contact area;occlusal force;longitudinal study;retention.

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This report presents the improvement of the prosthetic treatment by the reconstruction of occlusion using bone grafting in adulthood for a case with bilateral cleft lip and palate whose treatment was initially attempted by prosthetic measures only.
The patient was a female adult with bilateral cleft lip and palate. Primary lip repair was carried out at the ages of 6 and 9 months, respectively, while palatoplasty was performed at the ages of 1 year and 9 months, followed by revisionary lip surgery at 6 years 11 months old. Since initial examination for orthodontic care at 7 years old.
A Hawley-type retainer with artificial teeth to replace some missing anteriors which was to be replaced by a metal retainer later was applied at the age of 14 years after temporary orthodontic treatment. Re-examination revealed the necessity of alveolar bone reconstruction for prosthetic rehabililtation; thus, bone grafting in the region of the alveolar cleft was planned using autogeneous particular marrow and cancerous bone harvested from the illiac crest. After that, corrective orthodontic treatment using the multibracket system was completed sparing the space for the upper central incisor which requires prosthetic treatment.

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The number of adult surgical orthodontic patients at the Department of Orthodontics Showa University Dental Hospital has dramatically increased over the past few years. The Departments of Surgery, Dental Prosthodontics, etc. follow a team approach for the treatment of such patients. For the team members to share a common diagnosis and treatment plan, relevant departments hold regular meetings, which are called MFCs (Maxillofacial Conferences). MFCs are always held at least twice, before beginning presurgical orthodontic treatment and after its completion. In the Orthodontic Department, medical information on the patient and any discussion at the MFC is recorded on a form. However, some information, such as the surgical operation and the final results of orthodontic treatment is not included on the form because MFCs are not held after the operation. In addition, since this information is not added to a database, any information must be retrieved manually from the ledger. It is very useful to manage medical information. Therefore, we used the LAN of our dental hospital to construct a database system for surgical orthodontic patients which enables data entry for the patient and also makes it possible to search and peruse the data. In this report, we summarize the current usefulness of this system and discuss its planned application.

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A statistical investigation was carried out of 388 patients with cleft lip and/or palate in the Department of Orthodontics, Showa University Dental Hospital. The following findings were obtained.
1. The frequency and variation of cleft types were CLP 55.4%, CP 21.6%, CLA 18.1%and CL 4.9%. The female/male ratio was 1.9 in CP. However, of the remaining cleft types, males had the higher ratio. The left/right ratio, Unilateral CLA and CLP was over 2.0.
2. The frequency of the 1_??_3 type of cleft position was the highest (46.8%) followed by the 1_??_23 type (40.6%) and 12_??_3 type (7.4%).
3. 209 out of 388 patients (53.9%) had a congenital missig tooth abnormality. 4. The frequency of congenital missing tooth abnormality was CLP 69.8%, CP 38.1%, CLA 31.4% and CL 26.3%. The frequency of supernumerary tooth abnormality was CL 21.1%and CLA 14.3%.
5. The most frequently congenitally missing teeth were upper lateral incisors, followed by upper second premolars and lower second premolars in all cleft lip and/or palate patients.
6. In CL patients, 2 was found to be the highest frequency supernumeray tooth abnormality, followed by 5 in congenital missing. In CLA and CLP, 2 was found the highest frequency missing tooth abnormality. In CP, 5 was found to be the highest frequency missing tooth abnormality, followed by 2 congenital missing.
7. Cleft lip and/or palate patients demonstrated various types of missing tooth pattern in different cleft types.

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