Many tendon/ligament marker molecules play a role in healing and maintenance of constancy of periodontal ligament as well as tendon/ligament. These molecules also regulate chondrogenic differentiation. Further, transforming growth factor-β (TGF-β) stimulates tendon healing and chondrogenic differentiation. In the present study, the changes of the tendon/ligament markers expression by induction of chondrogenic differentiation and TGF-β3 treatment are assessed in human periodontal ligament cells (HPLC) and human mesenchymal stem cells (HMSC). Both cell types expressed various tendon/ligament marker genes; periostin, periodontal ligament associated protein-1 (PLAP-1) /asporin, biglycan, decorin, cartilage oligomeric protein (COMP), scleraxis, growth and differentiation factor-5 (GDF-5). When each cell type was aggregated into micropellets and incubated in chondrogenic differentiation medium (CDM) supplemented with TGF-β3 in 3 weeks (w), chondrocyte-like lacunae formation was detected in HMSC pellets, but not in HPLC pellets. In both pellets cultured for 1 and 2 w in CDM with TGF-g, expression levels of periostin, PLAP-1, biglycan and decorin genes were higher, but GDF-5 and COMP gene expression were lower levels, as compared with these pellets cultured with MSC growth medium, which did not induce chondrogenic differentiation. Further, scleraxis gene expression did not change throughout the culture periods. In monolayer cultures of HPLC, TGF-β3 stimulated expression of periostin, PLAP-1, biglycan, scleraxis and COMP, but suppressed GDF-5 expression, while, this cytokine had no effect on decorin expression. These results demonstrate that the expression of these tendon/ligament marker molecules in HPLC and HMSC is modulated under the conditions, which induce chondrogenesis, as well as by the TGF-β3 stimulation.

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Previously, a slit-shaped enamel defect had been observed in a premolar with enamel hypoplasia in the innermost enamel adjacent to the DEJ, where an abnormal step-shaped appearance was seen. In these observations, we happened to find the abnormal tubule- or elongated club-shaped defects in the ground enamel sections of 2 human permanent teeth containing an upper incisor and a third molar when observed the ground sections of 252 human teeth. The defects arose as the thicker club-edges from the innermost enamel adjacent to the dentin-enamel junction (DEJ) and the club-tips gradually thinner towards the enamel surfaces. The maximum length was about 500 μm and the thick club-edge defects were up to about 50 μm in width and contained minute granular deposits, which might be identified as whitlockite. The similar defects which showed many circular defects of the innermost enamel running along the DEJ were also observed in a third molar. Their enamel defects might be caused by the entire disappearance of the initially formed ameloblast groups or the partial break in the ameloblast activity during short or longer time of enamel formation.

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We examined the origins of the remarkable perikymata on the human permanent enamel surface mainly by using the 252 ground sections obtained from 252 teeth, although several investigators have reported their relationship in enamel hypoplasia. In these observations, the origins were roughly classified into 5 types (1-5). Some sigmoid or curbed lines of Retzius formed the wide or relatively narrow perikymata associated with the irregular dentin-enamel junction (DEJ) (type 1). One clear straight line of Retzius without the irregular DEJ formed the shallow perikymata followed with the clear or somewhat unclear lines of Retzius that converged towards the perikymata (type 2). The appositional enamel formation was concerned with the 2 sub-origins including the remarkable perikymata on the initial points of the appositional regular (type 3-1) and irregular enamel deposited on the resting lines of the already formed enamel (type 3-2). In mild enamel hypoplasia, the abnormal formation of the DEJ was concerned with the 2 sub-origins including the remarkable wave- or scallop-shaped DEJ which induced the disorder of enamel prism directions so that the irregular perikymata was formed (type 4-1) and the extremely step-shaped appearance of the DEJ which induced the abnormal perikymata (type 4-2). No incremental lines of Retzius concerning with the remarkable perikymata as well as the type 4 were also observed in some teeth, probably partial enamel hypoplasia (type 5). Some of their origins (types 1-5) were complexes.

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The purpose of this study was to investigate the features of hyoid movement during swallowing in the pharyngeal stage, and to devise an effective rehabilitation method for disabled patients. The subjects of the study were ten persons with cerebral palsy (CP : 3 years 9 months-34 years 9 months) and eight persons with mental retardation (MR : 2 years 0 months-31 years 5 months). Differences of hyoid movement were investigated and compared regarding oral dentition and disability using videofluorographic images.
The results were as follows.
1. In CP subjects, upward displacement was larger for those with deciduous dentition than those with permanent dentition. On the other hand, in MR subjects, upward displacement tended to be larger for those with permanent dentition than those with deciduous dentition.
No significant difference was found according to age for the forward displacement of the hyoid among either CP or MR subjects.
2. A comparison of the average distance of hyoid movement in different directions revealed that there was no tendency for upward displacement to be larger for CP subjects, but there was a tendency for it to be larger for MR subjects with permanent dentition than those with deciduous dentition.
There was a significant difference between the CP permanent dentition group (0.36 ± 0.12) and MR permanent dentition group (0.66 ± 0.20). However, no significant difference was found in CP and in MR subjects regarding forward displacement. These results indicated that this method could be used to evaluate the special features of hyoid movement during swallowing by videofluorographic study for dysphagia rehabilitation for disabled patients with cerebral palsy and mental retardation.

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The patient, female and hereby discussed, was 24-year-6-month years old at the first examination. She had a unilateral scissors bite, occurred from the left first premolar to the second molar, and Angle Class II division 1 malocclusion with a severe crowding.
The orthodontic treatments given were a reduction in maxillary dental arch width and some improvement, which could be responded to an expansion into mandibular dental arch width, in the scissors bite on the left side. Appliances, used in sequence for maxilla through the treatment, were a reverse porter, a sliding plate and a lingual arch with arm. In the meantime, an expansion porter was applied for mandible. Considering the unilateral scissors bite, in these appliances ingenuity was devised in order for force system to be appropriate for each side, this actually means that its force system is different from the other side. After a remarkable recovery was observed regarding the left molar occlusion, we started to make an effort, with palatal arch and head gear, to maintain and to stabilise the recoverd left occlusion. Besides, she had extractions; maxillary rigth-and-left first premolars and mandibular left second premolar.
Thus the treatments were gradually provided and this patient eventually achieved both a functionally-stable occlusion and its normal occlusion for her individual personality.

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The patient, when first examined, was 12 years and 9 months old, female. She had a Class II malocclusion with maxillary right canine of impaction, and left premolar of lingual transposition.
At first, an attempt on the impacted maxillary right canine would be required to erupt spontaneously in the line of the arch following the extraction of the right first premolar and the left second premolar. After confirmed fully eruption of the canine, started to treat with multi-bracket system.
Mandibular deviation to left side due to the interference of left first premolar rotated. Therefore, improved on this rotation at an early stage and paid attention to obtained the stable mandibular position.
As the results, evaluation of the patient's records for the 2 years following completion of active treatment revealed to acquire stable occlusion

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Bisphosphonates is a pyrroline derivative that reduces bone absorption by specifically inhibiting osteoclasts, and is administered for the treatment of bone metastasis of breast or prostate cancer, osteoporosis and multiple myeloma. However, recently, some cases of osteonecrosis of the jaw have been reported in patients administered bisphosphonates in the United States and Europe. In Japan, 30 cases of osteonecrosis of the jaw related to the administration of bisphosphonate have been reported, most of which developed secondary to invasive dental theapy.
At our department, we have performed surgical treatment in 7 patients with osteonecrosis of the jaw that developed secondary to the administration of bisphosphonate.
Bisphosphonates associated osteonecrosis of the jaw is very difficult to recover. So we should have enough recognition to the bisphosphonates, and we should do an enough informed-concent to the patient, it is necessary to deeper co-operation with medical, and to make an effect to prevention and treatment of the osteonecrosis of the jaw.

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[in Japanese]

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