In order to elucidate the adhesive function and potential for proliferation of carcinogenesis in oral cancer, we immunohistochemically investigated the expression of p-cadherin and cyclin D1 in oral epithelial hyperplasia, epithelial dysplasia and squamous cell carcinoma. The expression of P-cadherin was observed in the basal cell membrane, except in the cytomembrane facing the basal membrane, in normal epithelium and in epithelial hyperplasia. However, expression was not observed in the cytomembrane of the prickle cells or keratinized cells.
The expression was observed in the cytomembrane from the basal cell layer to the prickled cell layer in epithelial dysplasia, and in the cytomembrane of cancer cells from the peripheral region of the nest towards the center. However, the ctyomembranes were not positive for P-cadherin in the region facing the stroma or in the cancer pearls. On the other hand, the expression of cyclin D1 was observed scattered throughout the basal cells in the normal epithelium and in epithelial hyperplasia. Expression was seen in the cells from the basal cell layer to the prickle cell layer, and in all the cancer cells of the nests. There was significant difference between the expression of P-cadherin and the histological level of differentiation (P<0.01), but no difference between the expression of cyclin D1 and the histological level of differentiation. There was significant difference between the expression of P-cadherin and cyclin D1 (P=0.045). P-cadherin was overexpressed in cells that had a high potential of proliferation in epithelial dysplasia and in SCC accompanied by overexpression of cyclin D1.
Therefore, P-cadherin is responsible not only for cell adhesion but also for the potential of cell proliferation. In addition, the overexpression of P-cadherin and cyclin D1 might be associated with a high potential for cell proliferation through factors regulating the cell cycle. Shika Igaku (J Osaka Odontol Soc) 2002 Mar; 65(1): 1-10.

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In order to improve the reactive layers, we fabricated commercial pure (CP) titanium cast crowns using experimentally produced phosphate-bonded investment materials in which Li₂O was added to Al₂TiO₅, and obtained the following results regarding behavior of the reactive layers. The compressive strength at a 1,000℃ firing temperature was more than twice that for 900℃ Surface roughness was the lowest in the CP titanium crowns cast at a firing temperature of 1,200℃ using the experimentally produced investment materials. Observation of the metallic microstructures showed black erosive areas resulting from etching when the experimentally produced investing materials were used. However, the etched erosive areas decreased when the firing temperature increased to 1,200℃. Analysis of the elements on the surface of the CP titanium crowns indicated that the reactive layers contained components of the investment materials on the surface of all specimens for all firing temperatures. The depth of the reactive layer was shallowest in the specimens cast with the smallest addition of Li₂O to Al₂TiO₅ at a firing temperature at 1,200℃. Shika Igaku (J Osaka Odontol Soc) 2002 Mar; 65(1): 11-22.

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We used two-dimensional finite element analysis to compare the mechanical reaction in tissues surrounding the maxillary central incisors for cases where force was applied to the lingual of the teeth and for those in which it was applied to the labial side. Using preoperative and postoperative cephalograms, movements of the maxillary central incisors during orthodontic treatment with lingual fixed appliances were compared to movements with labial fixed appliances during retraction of the maxillary incisors in maxillary bicuspid extraction cases.
Use of the two-dimensional finite element model showed that the maxillary central incisors were depressed bodily when vertical force was applied to the lingual surface of the tooth. The maxillary central incisor inclined labially when vertical force was applied to the labial surface of the tooth. The combination of vertical and horizontal forces inclined the maxillary central incisor lingually when force was applied to the lingual surface of the tooth, and the tooth was inclined labially when force was applied to the labial surface of the tooth. Cephalometric analysis indicated that the maxillary central incisors intruded more during maxillary incisor retraction on treatment with a lingual fixed appliance than they did with a labial fixed appliance. Shika Igaku (J Osaka Odontol Soc) 2002 Mar; 65(1): 23-30.

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A transpalatal arch is often used in orthodontic treatment for vertical control of the maxillary molars and expansion of maxillary inter-molar width. Patients with a transpalatal arch usually have difficulties with speech. To evaluate articulation changes over time with the transpalatal arch, we performed speech tests, time element analysis and formant frequency analysis of the unvoiced plosives /ka/,/ki/,/ku/,/ke/,/ko/,/ta/,/te/ and /to/.
We found that the cause of unclear pronunciation was frequently incorrect articulation of consonants and the subsequent vowels. Differences in the place of articulation affected aspects of self-compensation. Shika Igaku (J Osaka Odontol Soc) 2002 Mar; 65(1): 31-40.

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Using a non-contact three-dimensional measuring device, we measured the relative position of the maxillary anterior teeth and upper lip of 15 patients receiving treatment to correct overjet and 5 subjects with normal occlusion. We investigated soft tissue changes before and after retraction of the maxillary anterior teeth.
There was a high correlation between movement of the teeth and movement of the center of the lip and the angle of the mouth. These results indicate that it is possible to estimate the position of the lip after retraction of the maxillary anterior teeth. This research should be useful in treatment planning, including that for the form of the soft tissue. Shika Igaku (J Osaka Odontol Soc) 2002 Mar; 65(1): 41-48.

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To clarify how a stabilization splint affects mandibular position, we measured mandibular changes in movement at the incisal point (IP), right condylar point (RCP) and left condylar point (LCP) for patients with TMD (abnormal) and for a healthy control (normal) group. The tapping point was observed on placement of the splint and on just after its removal. In addition, we investigated changes in the tapping point three hours after placement. We analyzed variations in the tapping points and movements of three measured points (IP, LCP, RCP) on placement of the splint and just after its removal.
We found that the three points measured points moved forward in the TMD group when the stabilization splint was used, while they did not move significantly in the control group at the time of placement on after three hours. Although there was a significant difference in the distance IP moved between normal and abnormal group just after placement, there was no difference between the two groups after three hours.
These findings indicate that a stabilization splint guides mandibular position forward in patients with TMD. Shika Igaku (J Osaka Odontol Soc) 2002 Mar; 65(1): 49-58.

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The influence of antimicrobials against periodontopathic bacterial biofilm formation is still poorly understood. I examined 13 antimicrobials (ten protein synthesis inhibitors, one cell wall synthesis inhibitor and 2 DNA synthesis inhibitors) in terms of their inhibitory effect on exopolysaccharide (EPS) production by Prevotella nigrescens strains 22 and 23 isolated from periodontal pockets. Macrolides had the greatest inhibitory effect on EPS production. Although macrolides at 1/2 MIC reduced viscosity of the culture medium by 12 to 22% that of the controls, they did not affect the growth rate. When each strain was cultured with 1/2 MIC EM for 15 days, the viscosity decreased till the fifth day of culture, at which time it reached its lowest level for the rest of the culture period. After 15 days treatment with EM, all cultures from 50 colonies of each strain showed marked reduction in viscosity regardless of the susceptibility to EM. Colonies resistant to EM were not obtained. In conclusion, these results may suggest that EM has an inhibitory effect on EPS production by Prevotella nigrescens, and therefore might be useful in the treatment of periodontal diseases where EPS plays a key role in biofilm formation. Shika Igaku (J Osaka Odontol Soc) 2002 Mar; 65(1): 59-70.

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We studied the formation of new attachment at the ultrastructural level following application of enamel matrix derivative (EMD). Buccal dehiscence defects were surgically created on both sides of the maxilla in the first and second premolars of six monkeys. EMD was applied on the denuded root surface of the left side, but not on the right and the monkeys were sacrificed at 2, 4 and 8 weeks. The biopsies, including teeth, gingiva and bone, were comparatively examined with light and electron microscopes. During the early stages of healing, numerous active cells were accumulated adjacent to the dentin surface treated with EMD, and subsequently a large number of collagen fibrils formed between the dentin surface treated with EMD and the neighboring cells. This suggests that EMD has the potential to promote new attachment formation. Furthermore, intermingling of newly formed collagen fibrils with those from the dentinal matrix was frequently observed in the experimental group, resulting in a more intimate union of both tissues. Shika Igaku (J Osaka Odontol Soc) 2002 Mar; 65(1): 71-90.

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We studied changes in the microvasculature of the periodontal ligament and in the periodontal tissues that occurs when teeth lose occlusal function. We used 12-week-old rats to observe the lingual periodontal ligament in the middle and apical thirds of the distal root of the left mandibular first molar at 1, 3, 5, 7 and 14 days after loss of occlusal function. The microvasculature was observed with scanning electron microscopy, and the periodontal tissues were observed with light microscopy.
We found that few changes occurred in the microvasculature in the middle and apical thirds of the root at 1 day after loss of occlusal function. However, some changes such as narrowing of the blood vessels in the middle and apical thirds of the root were noticed at 3 days. The blood vessels were compressed and disappeared in the middle of the root as a result of narrowing of the periodontal space, and proliferated in the space near the bone as eruption of the tooth caused the width of the periodontal space to expand in the apical third at 5, 7 and 14 days. It was clear that morphologic changes in the microvasculature were different in the middle and apical thirds of the root. Shika Igaku (J Osaka Odontol Soc) 2002 Mar; 65(1): 91-105.

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I evaluated the effect of fluoride dentifrice on the surface of acid treated enamel. Enamel specimens 3 millimeters in diameter were prepared using a diamond core drill from extracted human incisors that were caries free and showed no signs of decalcification. The surfaces of the samples were highly polished using standard methods and immersed in 0.1 M HCl for 5 minutes at room temperature. The acid etched enamel specimens were treated for 5 minutes with either NaF solution (250 ppmF), NaF solution containing surfactant (sodium lauryl sulfate: SDS) or NaF-dentifrice solution for 5 minutes. The SDS concentrations were 0.1, 0.25, 0.5, 0.75 or 1.0%. The treatment was repeated 7 times at 24 hour intervals. Distilled water was used as a control.
The atomic force microscopy (AFM) observation indicated that the surface of the controls disappeared with acid treatment and the top of the enamel rods became flat. Fluoride reaction products from the NaF solution were observed on top of the enamel rods. However, when the SDS concentration was over 0.75%, when NaF dentifrice treatment was done, fluoride reaction products appeared at the bottom of the enamel rods inter space. Enamel crystals were larger than those in the controls for the enamels treated by immersion in SDS NaF solution and in NaF-dentifrice. The X-ray photoelectron spectroscopy (ESCA) analysis indicated that the F/Ca atomic ratio after treatment with NaF solution decreased from 0.23 at the surface to 0.06 in the 10^<th> layer. however, the ratio was almost the same for treatment with SDS･NaF solution or NaF-dentifrice. Fluoride uptake was less when the SDS concentration under 0.5%. However, when the SDS concentration was over 0.75% or when treatment was with NaF dentifrice, there was more of fluoride uptake at the 10^<th> layer than in other layers.
I concluded that surfactant treatment spread the fluoride ion uptake into enamel rod inter space and promote crystal growth of enamel. Shika Igaku (J Osaka Odontol Soc) 2002 Mar; 65(1): 106-120.

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We performed distraction osteogenesis (DO) on the mandibles of five cats and investigated its effect on the distracted inferior alveolar nerve (IAN). Immunoblotting techniques and the digastric electromyogram response evoked from the jaw opening reflex were assessed in the IAN before surgery, immediately after surgery, at the completion of distraction, and 1, 2, 3 and 4 weeks after completion of distraction. Latency significantly increased, especially immediately after surgery. However, immunological examinations confirmed that the latency tended to recover in the distraction group. This suggests that although function in the IAN was distracted by DO of the mandible, it tended to recover during the time frame of the experiment. Shika Igaku (J Osaka Odontol Soc) 2002 Mar; 65(1): 121-129.

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