To establish an immunohistochemical basis for orthodontic treatment, we review early histopathological changes and immunohistochemical changes of Runx2 and Msx2 in vivo study using mouse periodontal ligament exposed to mechanical stress. Strong expressions of Runx2 and Msx2 were seen in periodontal fibroblasts of the tension side at 20 minutes after mechanical stress. Expressions of Runx2 and Msx2 became stronger in parallel with time, and at 24 hours after mechanical stress, the periodontal fibroblasts, cementoblasts, and osteoblasts showed strong expression. Moreover, ALP has also demonstrated similar strong expression. All these results strongly suggested that Runx2 promoted differentiation of osteoblasts at an early stage and Msx2 worked as an activator of Runx2 function.

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The purpose of this examination was to in vestigate the expression of BMP-2 and -4 in mouse orthodontic periodontal tension sides exposed orthodontic mechanical stress using the method of Waldo. Immnohistochemically, in the experimental group, strong expression of BMP-2 and -4 were observed in the periodontal tension sides at 20minutes. The results strongly suggested that the BMP-2 and -4 promoted the Runx2 expression for osteoblastic differention in the orthodontic periodontal tension sides at the early stage after receiving of the mechanical stress.

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Midpalatal implant was developed as a new orthodontic implant system in 1996, Switzerland. Until now, there is no clinical statistical report involved in the midpalatal implant including the removal in Japan. The aim of this study is to report clinical statistics of orthodontic patients using the midpalatal implants and to propose an application of collagenous sponge material to the defect after the removal of the midpalatal implant. Forty-three patients (thirty-four females and 9 males, operation age: 15 years 3 months to 39 years 5 months, mean age: 21 years 10 months) received one screw-type endosseous implant each (lengths: 4 or 6mm, diameter: 3.3mm; Orthosystem^®, Institute Straumann, Switzerland) for maximum orthodontic anchorage. The success rate of the initial midpalatal implants (fixture length: 6mm) was 96.3% (26/27), while the success rate of the length of 4mm was 75.0% (12/16). In all cases, the success rate of the initial midpalatal implants was 88.4% (38/43). Five palatal implants were lost, but the osseointegrations of all 5 cases were achieved by the second implantations. In non-decalcified sections of the removed material, the pure titanium fixture connected with cortical bone, and the network of osteocytes and osteon structure were observed. At the removal after dynamic treatments, metal-like stains were adhered on the surfaces of the defect. The foreign bodies were removed from the defect surfaces by using a curette and/or a bar as possible. As our ideas for bone healing, available collagenous material (TERUPLUG^®) was filled in the bone defect, and then covered with an antibiotic ointment (Achromycin carboximethylcellulose sodium). The bioabsorbable medical material consists of 90% atellocollagen and 10% denatured collagen derived from bovine skin. All patients had no problems after accepting the midpalatal implants and the collagenous material filling after the removal. We believe that this sponge technique could contribute to bone healing after the explantation of the midpalatal implant.

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Heat shock proteins (HSPs) are induced by not only the heat shock but also the mechanical stress. Orthodontic tooth movement induced mechanical stress in the related periodontal ligament. It is important to examine the immunohistochemical profile change of the Heat shock proteins (HSPs) in the periodontal ligament cells after receiving the mechanical stress for orthodontic treatment. Therefore, we examined the HSPs in the periodontal ligament cells of ddY mice using the Waldo method. In the control group, periodontal ligament was observed as physiological arrangement, and which reacted weakly to HSP27 and HSP70. In the experimental group the extension site of the periodontal ligament cells and the expansion of the blood vessel occurred in the traction side. These tissues were strongly reacted to HSP27 and HSP70. The findings suggeste that the HSPs expression work as the mechanism of maintenance of homeostasis in the periodontal tissues.

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Tumors of the oral maxillofacial region consist of odontogenic and non-odontogenic tumors, and one often encounters tumor-like diseases that require differentiation from these tumors. When performing histopathological diagnoses of surgically resected tissues (surgical specimens), accurate evaluation of the extent of tumor expansion and the presence or absence of tumor in the surgical margin; as well as differentiation from similar diseases are necessary. Hence sectioning at the appropriate position is important. The present study examined the surgical specimens received since April 2008, which were subjected to microfocus X-ray CT (micro CT) imaging, sectioned based on the image findings, and processed for histopathological diagnosis. The micro CT images and histopathological findings were compared. Twenty-one cases were studied. The histologic types were squamous cell carcinoma in 16 cases (9 in mandibular gingiva, 4 in maxillary gingiva, 2 in buccal mucosa, and 1 inside mandibular bone), mucoepidemoid carcinoma in 1 case, ameloblastoma in 1 case, odontoma in 1 case, ectopic eruption of third molar in 1 case, and schwannoma in 1 case. In 18 cases of mandibular or maxillary bone resection for tumor removal, the presence or absence of bone resorption on micro CT image was in complete concordance with the presence or absence of histopathological bone invasion. Of 7 cases showing pressure type bone resorption on micro CT images, 6 cases showed expansive type and 1 case showed invasive type bone invasion histopathologically. Of 7 cases showing permeated type or moth-eaten type bone resorption on micro CT images, all showed invasive type bone invasion histopathologically. Therefore the patterns of bone resorption on micro CT images were almost consistent with the patterns of histopathological bone invasion. When comparing the presence or absence of tumor invasion in the mandibular canal and maxillary sinus, the results were concordant for the mandibular canal in all cases, and for the maxillary sinus in all but one case. While the internal state of the surgical specimen could not be discerned from the outer surface in the cases of odontoma and schwannoma because of the fibrous capsule and in the case of ectopic eruption of maxillary third molar due to the bony structure, the internal properties of these specimens could be identified on micro CT images, allowing sectioning at the appropriate position. The final diagnosis of oral diseases, including the extent of tumor invasion or expansion, depends on histopathological findings. For this purpose, appropriate sectioning is important and application of micro CT image is useful.

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