The purpose of this study was to investigate the initial bone tissue change and ,to repair on the Miniscrew and surrounding tissue under the various types orthodontic forces by use of niti closed spring through the polarizing φ>larizing microscopic fmdings. For this study, three young adult mongrel dogs(experimental group 1, 2, 3) were used, and 12 titanum miniscrew(a1, a2, a3, b1, b2, b3, c1, c2, c3, d1, d2, d3) were inserted into the palatal bone. The experimental design was consisted of equal opposite group(B), extrusion group(C), double same sided group(D). and group(A) was controlled. Group B, C, D miniscrews were loaded with 150gm of force immediately after placing to palatal side, and group B miniscrews were loaded with changed force of equal amount to buccal side after 10 없ys. and Group C was loaded extrusive force, group D was loaded double amount to palatal side at same time. The experimental animals in each group and control group were sacrified at one, three, and six weeks following implatation the miniscrew to make the samples for polarizing microscofic findings on palatal bone and miniscrew. All samples were examed and compared the 비stologic changes through the polarizing microscpe. The obtained results were as follows. 1. Under equal 01ψ。site force group, the histologic features of tissues around Miniscrew in experimental B group was no difference between the control group under equal opposite force group 2. Under extrusive force after lateral force group, it's bone density was decreased less than control groupunder extrusive force after lateral force group. πùs group was most p∞r bone densi마 ofall. 3. Under double same side group, inital feature was sirnlar to control group , but after 6weeks bone density was decreased along the Miniscrew surfaceunder double same side group. Based on these experimental results, in the prac디ce ， Miniscrew was usefull as skeletal anchorage in immediately load after implantation on alveolar bone under lateral force and opposite lateral force, but at applied extrusive force and double opposite side force were non- useful as skeletal anchorage with long-term treatrnent.

be involved in the development of oral SCC. If we compare the morphologic features of NHOK to IHOK according to calcium concentration by TEM, IHOK have been gained wide acceptance as a model system for HPV-linked oral carcinogenesis. We already have established immortalized oral keratinocytes(IHOK) transfected by E6 and E7 gene. The purpose of this study were to examined the ultrastructural features of cultured NHOK, IHOK, and HN4 oral squamous cell carcinoma cell line, and to apply these results to oral carcinogenesis in the future. NHOK from healthy retromolar pad was primarily cultured at 37oC and 5% CO2. IHOK, and HN 4 cell line which were cultured under 0.15 and 1.2mM Ca++ of KBM bullet kit. For transmission electronmicroscopy(TEM), under preconfluency, and after 3 days of postconfluency under 1.2mM Ca++, cultured NHOK, IHOK, and HN4 cell line were immediately fixed in 2.0% glutaraldehyde in 0.1M cacodylate buffer(pH 7.4) at 4OC for 1h. The ultrathin sections were stained with uranyl acetate and lead citrate, and examined by TEM. The obtained results were as follows. 1. TEM of cultured NHOK under 1.2mM Ca++ showed increased tonofilaments, and vaculated ovoid cells with cornified envelope, while cultured IHOK showed prominent microvilli, unilateral desmosome in microvillus, and tonofilaments. 2. TEM of HN 4 cell line sowed numerous microvilli, increased N/C ratio, and lateral desmosome in microvilli under 0.15mm, while under 1.2mM well forming desmosomes. From the aboving results, under high calcium cultured IHOK showed less tonofilaments than that of cultured NHOK, while cultured IHOK, and HN 4 cell lines showed more increased desmosomes under high calcium. It was suggested that the ultrastructural changes of cultured IHOK would be accepted as intermediate stage cells for studying oral carcinogenesis.

Anchorage plays an important role in orthodontic treatment. Recently, some clinicians have tried to use skeletal anchorage system(titanium miniscrews and microscrews) in treatment due to their many advantages such as ease of insertion and removal, low cost, immediate loading, and the ability to place miniscrews in any area of alveolar bone. The purpose of this study was to investigate the histopathologic change of alveolar bone density around miniscrew under variable ortho -donticforceinyoung-adultdogs, throughthepolarizingmicroscopic findings. For this study, three young adult mongrel dogs(6-months in age) were used, 12 titanium miniscrews were inserted into the palatal bone(4 miniscrews placed in each dog), and then miniscrews were loadedwithorthodonticforce [50gm(F1),100gm(F2),250gm(F3), 500gm(F4)] immediately after implantation. After 1, 3 and 6 weeks, the animals were sacrificed. Then the miniscrews and surrounding bone of dogs were removed, respectively. The grinding samples along the long axis of miniscrew were made. The changes of bone density and thrombosis were examined under the polarizing microscope. Bone density was determined as color changes. The results of this study were as follows. 1. There was no thrombosis in the F1 group. But thrombosis was seen in 1 week of T side, 1, 3, 6 weeks of P side in the F2 group, 1, 3 weeks of T side, 1, 3, 6 weeks of P side in the F3 group and 1, 3, 6 weeks of both P and T side in the F4 group. 2. The changes of bone density decreased in P side more than T side in 1 week, while more decreased P side in 3 weeks than 1 week. In 6 weeks, bone density more increased in T side than P side along the middle & apex. 3. As orthodontic force increased, there was severe thrombosis, especially in cervical of P side. As it went up to 3, 6 weeks, thrombosis was decreased but remained. 4. As orthodontic force increased, bone density more severely decreased due to bone destruction in 1 and 3 weeks, but more slowly increased due to bone formation in 6 weeks. Based on the results of this study, in the practice, because of optimal orthodontic force for the most of tooth movement was less than 150gm, I thought that miniscrews could play role of use of skeletal anchorage immediately after implantation. In the more than 250gm & 500gm of orthodontic force, I thought that miniscrews would be delayed as use of skeletal anchorage after loss of bone was restored.

E6 and E7 as two major oncoproteins of HPV can act together to produce several tumors, providing an evidence for the role HPV in oral squamous cell tumorogenesis. It is worthy to detect E6/E7 mRNA expression of HPV in oral carcinoma. The purpose of this study were to detect HPV mRNA in HNSCC cell lines, and to use these results to confirm oral squamous cell carcinoma. Semi-quantitative RT-PCR method for E7 mRNA expression in HNSCC cell lines should play an important role in detecting the early stage of oral squamous cell carcinoma.

Established SGT cell line from human submandibular gland adenocarcinoma was used to study the TGase expression on a cellular level in vitro. Transglutaminase 2(TGase 2) is assoacitated with apoptosis, GTP binding protein, and cell marix interaction. The role of TGase 2 in salivary gland tumors is not clear yet. The pupose of this study were to examine the TGase expression of SGT cell line compared to other tumor cell lines, and to apply these results to the pathogenesis of salivary gland tumor. TGase enzyme assay of SGT, SCC-15, HN 4 and HeLa tumor cell line was 3 times repeated, and calculated. Immunoslot blot for semiquantitative protein analysis was done. The obtained results were as follows. 1. SGT cell line showed the highest TGase 2 enzyme activity(about 6-16 folds) irrespective of pre or postconfluency. 2. HN 4 cell line showed the highest TGase 1 enzyme activity(about 2-3 folds) irrespective of pre or postconfluency. 3. Under postconfluency TGase 1 induction was not induced, but slightly increased in all tumor cell lines. 4. TGase enzyme activity in all tumor cell lines was accompanied with TGase protein formation. From the aboving results, the higher TGase 2 expression of SGT cell line suggested that they would come from submandibular ductal cells and have a important role in the pathogensis of salivary gland tumors.

As pulp calcification occurs at least fifty percent of total teeth, the focal calcification in pulp chamber usually appears in all age groups. However, the pulp calcification is one of the important pathologic changes affecting the pulp vitality. In order to elucidate the mechanism of pulp calcification during the retrogressive degeneration of pulp tissue we performed an immunohistochemical study for proteases (MMP-3, MMP-10, and cathepsin-G), antiproteases (TIMP-1, α1- AT) and proteins involving tissue protection (TGase-2 and HSP-70). In the normal pulp tissue MMP-3 and MMP-10 were weakly expressed, but cathepsin-G and TIMP-1 were rarely expressed. Around the calcifying tissue of MMP-3, MMP- 10, and α1-AT were predominant, but TIMP-1 and cathepsin-G were sparsely expressed. On the other hands, TGase-2 and HSP-70 were condensed in the proximal fibrous tissue. These data suggest that the pulp calcification is related to retrogressive pulp degeneration, which could be resulted in the incomplete digestion of the degenerated stromal tissue by different proteases. We presume that the aberrant protease digestion of chronic pulpal pathosis, i.e., sclerotic fibrosis, chronic pulp degeneration, etc., may enhance the dystrophic calcification in dental pulp.