The purpose of this investigation is to evaluate the effectiveness of Dental Aesthetic Index (DAI) in the assessment of malocclusion in Japanese. Plaster models obtained from 200 high school students aged 15 to 18 years were examined according to DAI. In addition, the agreement between Malalignment Index (MI), Occlusion Feature Index (OFI), Discrepancy Index (DI) and DAI in screening malocclusion was compared. The results were as follows : 1. Half of subjects had incisal crowding. The percentage of subjects with incisal spacing was 7%, and two thirds of them had diastema of 1 mm or more. The percentage of subjects with anterior irregularity on the upper and the lower arch was 83% and 68%, respectively. The percentage of subjects with anterior maxillary overjet and mandibular protrusion of 1 mm or more was 84% and 17%, respectively. About sixty percent of all subjects were mesial or distal to its normal relation. 2. There were differences among MI-TN, OFI-TN, DI-TN and DAI-TN groups as to which cases had malocclusion. These results suggest that the DAI is a more suitable screening tool in Japanese.

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Although several theories have been put forward, an important factor of bone regeneration is not yet exactly known. But the vascularization to bone wound is said to be a very important factor. The author has made a radiographic observation of correlation between vascularization of inferior alveolar artery and osteogenesis. The patient has a benign tumor in the right lower molar region. Partial osteotomy was performed from first premolar to third molar so as to include the inferior alveolar artery. At postoperative 37th day, thin and slight radiopaque appeared in the bone defect from the distal cut end part of the inferior alveolar artery (Cut end part 4mm in size). The radiopaque gradually developed and reached the cut end of medial bone at 706th day (10mm in size). The phenomenon suggested that new bone developed vigorously by new blood vessel and developed to protect the supply route of blood from strong irritation.

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In dental implants, the osseointegrating type is now predominantly used. When the implant is tightly bound to the bone, the functional loads involving vertical and lateral loads may be directly transmitted to the surrounding bone tissue. Thus the clinical performance with the osseointegrated implant seems to be largely dependent on the elastic and biological responses of the bone tissue to the loads. In the present study, therefore, a 2-piece hydroxyapatite-coated titanium implant was placed in the dog mandible and the histological changes in the surrounding bone tissue were examined by designing to apply lateral load in occlusion. The results suggest as follows : 1. The bone tissue obviously showed correspondent responses to the particular functions. 2. Significant differences were found in the response by the condition of the bone in which the implant was placed as well as by the degree of the bone resorption in the cervical region. 3. A response to the tensile stress appeared in the tension side such as the distal cervical region and mesial apical region by the applied lateral load, indicating that this type of implant might also be superior in the stress distribution in function.

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The tongue is considered to be an important factor for maintenance and stability of the morphology of the dental arch. Effect of changes in the morphology and function of the dental arch however has not yet been clarified. Effect of reduction and enlargement of the tongue of rats on the tooth position and effect of removal of muscle function on tooth position by excision of the medial nerve or lateral nerve of the hypoglossal nerve therefore were investigated histopathologically. In control group, the upper molars extruded lingually and the lower molars inclined bucally. The upper and lower incisor teeth displaced labially. In the reduced tongue groups, the upper and lower bilateral molars inclined lingually. The lower incisor teeth however showed no displacement. In the enlarged tongue group, the upper and lower bilateral molars showed buccal inclination and the lower incisor teeth slight lingual inclination. In both the right medial nerve excision group and lateral nerve excision group, the upper and lower bilateral molars showed marked extrusion. The degree of extrusion in the lateral nerve excision group was a little less than that in medial nerve excision group. The lower incisor teeth in the lateral nerve excision group showed lingual displacement. The upper incisor teeth in all groups showed no difference as compared with those of control group. On the basis of the foregoing findings, the morphology and the function of the tongue plays an important role as a factor in determination of tooth positions.

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Three-week-old male rats of Wistar strain were given normal food, calcium deficient food, vitamin D deficient food, or calcium deficient food + vitamin D deficient food, and changes in the alveolar bone were investigated radiologically, and light and electron microscopically. The results were as follows : 1. Findings from the analysis on the X-ray microanalyzer Quantitative analysis of Ca and P in the four groups showed no significant difference between the normal food control group and vitamin D deficient food group. However, significant difference with 1% significance level was found between the normal food control group and calcium deficient food group and between the control group and calcium and vitamin D deficient food group. The control group showed high values. Furthermore, relative Ca ratio (Ca/[Ca]c) and relative P ratio (P/[P]c) as compared with those of the control group were determined. In (Ca/[Ca]c), the normal food control group and vitamin D deficient food group showed high values followed by the calcium and vitamin D deficient food group and calcium deficient food group in descending order. In (P/[P]c), the normal food control group showed the highest values, and vitamin D deficient food group, calcium deficient food group, and calcium and vitamin D deficient food group showed low and the same values. 2. Histopathological findings In the alveolar bones of the calcium deficient food group as compared with those of the normal food control group, enlargement of bone marrow, decrease in Haversian system, enlargement of Haversian canals, and resorption cavities were marked, and bone tissue was displaced by low calcification layers. In the vitamin D deficient food group, bone marrow showed an increasing tendency and bone lacunae showed about the same findings as those in the normal food control group. The calcium and vitamin D deficient food group showed increase in bone tissue and increase in areas of low calcification layers as compared with the calcium deficient food group. 3. Scanning electron microscopic findings As compared with the alveolar bones of the normal food control group, those in the calcium deficient food group showed bone resorption in excess of bone formation, wide resorption cavities, shallow cavity bottoms and networks of collagen fibrils. Bundles of collagen fibers were not observed. The vitamin D deficient food group showed findings of bone resorptions and bone formation, and showed balanced bone construction. Bundles of collagen fibers were formed in bone matrix and openings of bone tubles were seen. The calcium and vitamin D deficient food group as compared with the calcium deficient food group showed bone matrices in part near the sites of bone resorption. However, osseous layers on the whole were decreased. On the basis of the foregoing findings, with regard to changes in the alveolar bone due to vitamin D deficiency, the effect on the bone tissue was great when calcium is deficient.

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Various stages of dysplasia are seen pathologically in the surrounding oral mucosal epithelium of oral squamous cell carcinoma. It is feared that carcinoma from residual cancer cells develops into the surrounding mucosa after macroscopic resection alone of the lesion. In recent years, cancer-related antigens for malignant tumors have been developed and immunohistochemical studies using them have been active. These antigens have been evaluated positively as clinical indicators for diagnosis, clinical progress, prognosis, and others. Fifty cases with squamous cell carcinoma in oral cavity were investigated pathologically and immunohistochemically. Immunohistochemical studies examined localization of carcinoembryonic antigen (CEA), keratin and epithelial membrane antigen (EMA) on carcinoma and epithelium of the surrounding site. The results were as followed : 1) With the histological grading of squamous cell carcinoma cells, 33 cases were well differetiated type, 10 cases were the moderate differentiated type, and 7 cases were poor differentiated type. With the epithelium of the surrounding site, 15 cases were the mild or none epithelial dysplasia (Class I), 19 cases were the moderate epithelial dysplasia (Class II), and 11 cases were the severe epithelial dysplasia (Class III). There were no correlations between the grading and the epithelial dysplasia of the surrounding site. 2) CEA, keratin and EMA were closely correlated with dyskeratosis of keratinized area and epithelial pearls. Also, the reactions rose with the rise in the grading, and the reactions of CEA and keratin also rose with it in the cellular stratum like spinous cell adjacent to the keratinized area. 3) EMA was detected in the poor differantiated type where CEA and keratin were negative, it was useful as the epithelial marker. 4) The surface of the keratinized epithelium of the surrounding site of the carcinoma was parakeratinized or hyperkeratinized epithelium, in the majority of the case, and the case of hyperplastic stratum spinosum also was found. 5) The reactions of CEA, keratin and EMA tended to increase with Class II and III than with Class I in the parakeratinized epithelium. CEA showed few cases in the stratum spinosum, but it showed positive reactions in the upper hyperplastic stratum spinosum. Keratin showed strongly positive with Class II and III. In the stratum basale, CEA was negative, and keratin showed the cases of strongly positive, moderately positive with Class II and III. 6) On the basis of the foregoing findings, CEA, keratin and EMA demonstrated biological quality with rise in keratinization of oral squamous cell carcinoma. It is useful for judgement of the grading and the parameter of canceration to the surrounding tissue. These findings provide indications in planning the surgical safety margin for surgical resection of squamous cell carcinoma.

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Nuclear DNA contents of oral squamous cell carcinoma cells were measured using MMSP-TU system (Microphotometry method). At first, the methods of material treatments were discussed and in 19 cases who were all had oral squamous cell carcinoma, the changes of nuclear DNA content after neo-adjuvant chemotherapy and radiation therapy were studied. The results were as follows. 1. When thin sections of 5μm, 10μm, and of cell isolation of 30μm were compared, no significant differences were found in the mean values of nuclear DNA content and a 90% agreement was shown between 10μm and cell isolation. Sections of 10μm therefore were used for this study. 2. In changes in nuclear DNA pattern by pre-operation treatment, 6 cases showed a shift toward left, 11 cases no change and 2 cases a shift toward right. In 6 cases whose nuclear DNA pattern shifted toward left, the means of nuclear DNA content of 5 cases were decreased (those of 3 cases were significantly decreased). In 2 cases whose nuclear DNA pattern shifted toward right, the means of nuclear DNA contents of all cases were increased. 3. In the group which used 5-FU at pre-operation, 9 of 12 cases showed decrease of the means of nuclear DNA content (those of 4 cases were significantly decreased). On the other hand, in the group which did not use 5-FU at pre-operation, only 3 of 7 cases showed decrease (there were not significantly decreased). 4. On the histological effect by pre-operation treatment, 4 of 6 cases whose nuclear DNA pattern shifted toward left showed over-GIII. 9 of 10 cases whose histological effect was over-GIIb (effective) showed decrease of the means of nuclear DNA content. In contrast, 6 of 9 cases whose histological effects were G I and G IIa (non-effective) showed increase of the means of nuclear DNA content. 5. By pre-operation treatment, 71.4% of the cases whose nuclear DNA pattern was type IV at biopsy showed effective (over PR). This was higher as compared to 63.6% of type III. But in the cases of type IV, there were histologically more invasive cases and so the prognosis was worse. Especially, in 2 cases were type IV of nuclear DNA pattern at biopsy and showed increase of the means of nuclear DNA content by pre-operation treatment, prognosis was not good. 6. In 7 of 8 cases whose gross pattern was ulcer type, nuclear DNA pattern did not change by pre-operation treatment and 4 cases of these were histologically non-effective (MR or NC). 7. In 6 of 7 cases whose nuclear DNA pattern showed type IV, durations were within 2 months. In 6 cases whose gross pattern was ulcer type and whose durations were within 2 months, all showed T3 or T4 and 3 cases had metastases of regional lymph nodes. It is suggested that nuclear DNA content is one of the available parameters to estimate histological effect by pre-operation treatment and that nuclear DNA content is a high risk factor in prognosis.

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The observation of the nerve distribution in the experimental hamster lingual cancer induced with 2.0% solution of 9, 10-dimethyl-1, 2-benzanthracene (DMBA) in acetone in the tongue of the Syrian hamster has been presented. The result were as follows : 1. Malignant epithelial tumor was found in 38 (76.0%) of 50 animals used for this study. 2. All malignant epithelial tumors were classified by the general histological findings, the behavior, as follows ; the ulcer type, the exophytic type, the exophytic polyp type with pedunculated and with sessile. 3. In the ulcer type, the granuration tissues forming around the ulcer have an amount of nerve fibers and nerve bundles of a middle and small sizes, but the nerve fibers and nerve bundles among the small nest of carcinoma cells were swollen slightly. 4. In the exophytic type, the single nerve fibers were seen frequently in the fibrous granulation tissues being formed beneath the mucosa, and among the epitherial pegs on developing. 5. In the exophytic type with pedunculation, the nerve bundles of the middle and small sizes, and the single nerve fibers were seen frequently in the comparatively wide stroma in the center of the polyp, though these were seen swollen and cracking. 6. In the exophytic type with sessile, the nerve tissues almost disappeared in the narrow stroma among the tumor cells. The nerve tissues were only in the little wider stroma of the tongue border, though these were not seen in the normal figure. 7. Regeneration of the nerve fiber in malignant epithelial tumor was not seen. As stated above, it is suggested that the difference of the nerve distribution in malignant epithelial tumor is related with the time process of tumor development and the development type of tumor, and that the nerve distribution is the one preexisting at the time of the growth of malignant tumor or regenerating nerve tissue in the process of the wound healing prior to the malignant tumor growth.

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Three-week-old male rats of Wistar strain were given a calcium-deficient diet and bone debility was induced in them experimentally. The rats were then given additional daily injection of ECT (0.2u/kg, intramusculary injection), a synthetic eel calciton in derivative, and 1α-OH-D_3 (0.1μg/kg, oral administration), an analogue of active type vitamin D_3, three times a week for four weeks. The effect of the combined treatment on the mandibular condyle at growth stage was investigated. The results were as follows : I. Histopathological findings A. CMR findings Granular trabeculae of primary spongiosa in the calcium-deficient diet + ECT + VD_3 group showed an increasing tendency in comparison with the calcium-deficient diet group. Trabeculae of secondary spongiosa in the calcium-deficient diet + ECT + VD_3 group was thicker but calcification was about the same in degrees as compared with that. B. Light microscopic findings The caltilage layers in the calcium-deficient diet + ECT + VD_3 group were thinner due to decrease in hypertrophic chondrocytes in comparison with the calcium-deficient diet group. Increase in calcified matrices surrounding hypertrophic chondrocytes and in findings of erosions of calcified matrices by chondroclasts were seen sporadically. Though trabeculae were thin and many portions of low calcification layers were seen. II. Electron microscopic findings In the scanning electron microscopic obsevation of cartilage layers, cartilage lacunal walls in the calcium-deficient diet + ECT + VD_3 group were occupied by calcospherites and portions with distinct bone lacunae were found in numbers, as compared with the calcium-deficient diet group. In the transmission electron microscopic observation, osteoblasts in the calcium-deficient diet + ECT + VD_3 group showed an increasing tendency and findings of high organelle activities were seen, as compared with the calcium-deficient diet group. Osetocytes showing osteocytic osteolysis that was found in the calcium-deficient diet group decreased in the calcium-deficient diet + ECT + VD_3 group. Osteoclasts in the calcium-deficient diet + ECT + VD_3 group showed conditions of restraint of their organelle activities as compared with the calcium-deficient diet + ECT group and the calcium-deficient diet + VD_3 group. In the calcium-deficient diet + ECT + VD_3 group, scattered findings of many cell clusters appearing to be young osteoclasts were charactertistic in comparison with the calcium-deficient diet group. On the basis of the foregoing findings, the combined treatment method of ECT and 1α-OH-D_3 for bone debility in the mandiblar condyle showed acceleration of growth of cartilage layers and bone construction, but it did not necessarily produce desirable results.

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Immature permanent teeth of young adult dogs were displaced by placing force of 50g and 200g on them and the effect of displacement on root growth and apical closure was investigated light and electron microscopically. The results were as follows : 1. Change in the 50g group Although deformation of Hertwig's epithelial sheath was seen on the compression area light microscopically in short term cases, the root apex was closed by connecting cellular cementum and growth of dental root by formation of root dentine was observed in the end. Apposition of cementum however was decreased compared with the control group. Scanning electron microscopy showed large and small resorptive lacunae of the alveolar bone and apposition of new bone. Transmission electron microscopy showed marked destruction of cells one to two weeks after displacement. The tension area did not show deformation of Hertwig's epithelial sheath but showed root growth and apical closure light microscopically. Scanning electron microscopy did not show resorption of the dental root or of the alveolar bone. Transmission electron microscopy showed cementblasts, osteoblasts and fibroblasts of high cell activity. After maturation, however, cells of low activity were found. 2. Change in 200g group On the compression area, deformation of Hertwig's epithelial sheath was seen light microscopically and root growth and apical closure were delayed as compared with the 50g group. Scanning electron microscopy showed restoration of the resorption findings of the dental root and alveolar bone. Transmission electron microscopy showed marked appearances of osteoclasts, marked organelle, and active ruffled border. On the tension area, the light microscopic findings were about the same as those of the 50g group and deformation of Hertwig's epithelial sheath was not seen and apposition of new trabeculae in the alveolar bone in particular was marked. Scanning electron microscopy did not show resorption of dental root or of the alveolar bone. Transmission electron microscopy showed rough surfaced endoplasmic reticulum, cementblasts with developed Goldi apparatus, osteoblasts, and fibroblasts. Characteristic suggestive of high cell activity was seen. After maturation of dental root, organelle decreased. On the basis of the foregoing findings, although displacement of immature permanent teeth by continuous force of 50 to 200g caused deformation of Hertwig's epithelial sheath and poor formation of dentine and cementum in the apical region to some extent, it was clear that periodontal membrane fibers were functionally arranged between the teeth and the surrounding alveolar bone.

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Early clinical diagnosis of oral cancer and determination of effect of treatment are possible under direct vision. For determination of insufficient control in deep tissue and metastasis, however, clinical examination routinly performed and tumor markers attracting attention recently are of reference. Organism with cancer, on the other hand, has tumor and host relationship. For the purpose of demonstrating correlation between examination findings and progress, therefore, serum of patients with oral cancer was added to KB cells derived from oral cancer in logarithmic phase in vitro and correlation between growth of KB cells and progress was examined. Whether this correlation can be used as a screening test was also examined. The results were as follows : 1. Patients with squamous cell carcinoma in oral cavity as compared with patients with benign oral disease showed significant decrease in erythrocytes, serum total protein, albumin, A : G ratio, and significant increase in alpha-1, 2-globulin, LDH, ALP, IgA and serum IAP level. In progress of clinical stage, statistically significant difference was found in each of erythrocytes, albumin, A : G ratio and alpha-1-globulin of Stage II cases ; erythrocytes, albumin, A : G ratio and alpha-1-globulin of Stage III cases ; erythrocytes, leukocytes, albumin, A : G ratio, alpha-1, 2, ganma-globulin, IgG and serum IAP level of Stage IV cases, as compared with patients with benign oral disease. 2. In change in measurements before and after treatment, with progress of clinical stage, no statistically significant difference was found in any measurement before and after treatment in Stage I and II cases. In Stage III cases, however, statistically significant difference was found in alpha-1, 2-globulin before and after treatment. Stage IV cases showed statistically significant difference in alpha-2-globulin before and after treatment. Positive correlation was found between growth of KB cells and alpha-1, 2-globulin. In contrast, negative correlation was found between growth of KB cells and the number of lymphocytes. 3. In cases with good prognosis, growth of KB cells was within or less than control level. In cases with poor prognosis, most cases were more than control level. Statistically significant difference was found between the cases with good prognosis and those with poor prognosis. In the measurements before and after treatment between the cases with good prognosis, statistically significant difference was found in albumin, A : G ratio and alpha-2-globulin. The cases with poor prognosis before and after treatment showed statistically significant difference in the number of lymphocytes, and alpha-1, 2-globulin. Of those, alpha-1, 2-globulin showed positive correlation with growth of KB cells. In contrast, the number of lymphocytes and A : G ratio showed negative correlation. 4. Serum IAP level before treatment in Stage III and IV cases increased significantly as compared with benign oral disease and Stage I cases. In cases with good prognosis, the level decreased significantly and tended to become negative, whereas in the cases with poor prognosis, the level increased significantly after treatment. From these, marked positive correlation was found between serum IAP level and growth of KB cells. 5. On the basis of the foregoing findings, reference to growth of KB cells, after adding serum of patients with oral cancer to KB cells and cultivating it, appears to reflect severity of condition in squamous cell carcinoma in oral cavity, and may be a useful indicator for estimating clinical course, effect of treatment, and prognosis, and may be used as a screening test.

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Collarless ceramo-metal crowns have been widely used because of their superior esthetics at the shoulder as well as the protection of the gingival margin from direct exposure to metal. There are, however, some difficulties in fabricating the crown with satisfactory marginal fit and/or correcting the contour of the loosely fitting porcelain shoulder. In order to overcome such problems in this study, the light-curing process was attempted for forming the porcelain with the experimental monomers. The monomers were composed of 1, 3-butanediol dimethacrylate monomer (BDMA) as a base monomer, glycidil methacrylate monomer (GMA) as a diluent, dl-camphor quinone as a photosensitizer, and N, N-dimethyl-p-toluidine as a reducing agent. Four monomers with different BDMA to GMA ratios were prepared : 1 : 0 0 (referred to as M_<1-0>), 1 : 1 (M_<1-1>), 1 : 1.5 (M_<1-1.5>), and 1 : 2 (M_<1-2>). Their performances were discussed by comparing with the porcelain formed with distilled water followed by firing at 900℃ as a control. The porcelain formed by the light-curing process showed 10 to 15% larger volumetric shrinkage in firing than the control because the porcelain powders could be less incorporated in the mixture with the viscous monomers. The shrinkage not only compensated for the lowered density of the porcelain but also markedly reduced the size of porosities except for the monomer M_<1-0> that produced significantly larger size and number of porosities in the fired porcelain. It was reflected in the compressive strength not smaller than that of the control. When the porcelains formed with the monomers were fired at a temperature lower than 850℃, the shade turned blackish due to the incomplete combustion of the polymers. However, distinguishable color differences could no more be found after firing at 900℃ among the control and the porcelains formed with M_<1-0>, M_<1-1> and M_<1-1.5>. The monomers were applied to form the shoulder porcelain at the margin of the collarless ceramo-metal crown on the plaster die to correct its margin contour. When distilled water was routinely used, a considerable amount of porcelain powders remained on the die shoulder in lifting the crown. With the use of M_<1-0> and M_<1-1>, however, almost all the powders could be withdrawn as a bulk from the die together with the crown, although no improvements were found on the separation from the die with M_<1-1.5> and M_<1-2>. As a result, the margins showed excellent fit to the die shoulder after firing when M_<1-0> and M_<1-1> were used for formation, while larger marginal gaps were observed in the cases of the control and the other two monomers. From the foregoing findings, it was suggested that the light-curing forming of the shoulder porcelain with the experimental monomer M_<1-1> would be an extremely useful technique for improving the workability and marginal fit without adversely affecting the physical and mechanical properties.

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It is very difficult to reposition the upper central incisors or to assume and determine the vertical dimension when the upper anteriors and/or the occlusal stop by natural teeth were lost, although they are important esthetically and functionally. The faces of adult Japanese with normal occlusion were esthetically analyzed in order to make reference on the position of the upper incisors and the height of vertical dimension. The results were summerized as follows : 1. The triangle which was formed by left and right external ocular angle points and upper incisor point was nearly an equilateral triangle. It was thought as the facial triangle which had been reported the most important parts for facial expressions. 2. The height of the incisal edge of upper central incisors was quite close to the lip conjugate point. 3. The tip of the upper lip was coincident with the esthetic line, which is a line drawn between the pronasal point and the mental point, when the face was viewed from the lateral side. 4. The incisal edge of the upper central incisors was located 13mm anteriorly from the posterior edge of the incisive papilla. 5. The cross point of the left and right extended lines of the pupil point and the ala nasi point were coincident with the mental point. This can be used as a reference to judge the vertical dimension, esthetically.

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In case of a malignant tumor or a part of benign tumors occurring in the mandible, hemimandibulectomy might be performed. Recently autologus or artificial bone has been used for reconstruction of such cases. However, for the youngsters in their growth periods, the reconstruction used to be postponed until their development is completed, even if it is a benign case, since primary reconstruction could also be a problem for growth. On the other hand it has been reported that in those youngsters osteoanagenesis similar to the former jaw bone is feasible when the periosteum remains therein, even if hemimandibulectomy associated with great defect of the jaw bone is performed. Thus, the author studied changes of the temporomandibular joint remaining after hemimandibulectomy along the regeneration process of the jaw bone. Fourteen adult hybrid dogs about 6 months after birth were used. The right mandible was resected at the first distomolar part, detaching periosteum up to the temporomandibular joint. After that the left temporomandibular joint was observed diurnally. Observations were made 7, 14, 21, 30, 60, 90 and 180 days after the operation. After embedding the temporomandibular joint in celloidin, sections of 15μm were prepared and observed under the light microscope after staining with HE. As the result the following was known. 1. Changes of tissues at the temporomandibular joint was strongly noted at the initial stage after surgery, which was stabilized by 60 days. Characteristic changes were noted on the articular disc by 180 days after the operation. 2. Front edge of mandibular corpus showed absorption of the bone from 7 to 21 days after the operation, which was markedly strong inside compared with that outside. After that changes were not noted for a while, but absorption of the bone was again noted 90 days after the operation, and by 180 days osteoclast was not observed any more. 3. The cartilaginous zone of the mandibular head increased width of the differentiated zone markedly by 7 days after the operation, but from the 14th day onward its width decreased being irregular in convexoconvex by 21 days after the operation. After that it proceeded without changes, but 90 days after the operation again the width of the cartilaginous zone decreased to make a narrow medullary cavity by 180 days after the operation. 4. In the articular disc and tissues therearound, starting from the 7th day after the operation, changes occurred in alignment of fascicles in the posterior hypertrophied part of the articular disc, which by the 21st day of the operation showed small undulatory running on the side facing at the superior articular cavity. Furthermore, in the articular cavity, 7 days after the operation proliferation of the synovial portion was noted at the terminus, and 21 days after the operation tiny projection of the connective tissue was noted. On the other hand in the disc tissue, running of the fascicles differed between that on the mandibular head and that on the articular fossa by 90 days after the operation. In the posterior connective tissue alignment of fascicles began to be thinner, then by 180 days after the operation on the articular fossa tear of the disc tissue was noted. 5. Changes occurred on the articular fossa according to changes of the articular head. It means that, in the deepest part of the articular fossa regeneration of the bone was noted on the 14th day after the operation, while at the anterior articular fossa increase of the cartilage layer was noted initially at the anterior articular fossa, and 21 days after the operation at the posterior articular fossa. After that the course progressed without changes, and 180 days after the operation tear of the fibers was noted at a part of the fibrous covering at the posterior part of articular fossa. From the result of experiments as above, it was suggested that induction of the lower jaw after hemimandibulectomy

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A survey of the oral health conditions and treatment needs of dental diseases was conducted among 181 bedridden elderly people living at home in Kitakyushu City, Japan. The purpose of this study was to provide baseline data before the planning and implementation of a dental program for bedridden elderly people in Japan. Dentition and periodontal status, wearing of and need for dentures, and the condition of the temporomandibular joint were assessed according to the WHO guidelines (Oral Health Surveys-Basic Method, 3rd Ed., 1987). Interviews were also conducted and data on the general diseases was obtained from the subjects' medical histories. The most frequent causes of being bedridden were cerebrovascular diseases followed by cardiovascular diseases and senility. Mental status was also surveyed. The percentage of the subjects in good, fair and poor mental condition was 29%, 50% and 20%, respectively. Forty-three percent of all persons were edentulous and the mean number of present teeth, DF teeth, D (dacayed) teeth and F (filled) teeth among dentate persons was 9.6, 7.0, 3.9 and 3.1, respectively. The average number of teeth requiring filling, pulp care, crown or bridge abutment and extraction among dentate persons was 1.0, 0.6, 0.1 and 2.4, respectively. The percentage of dentate persons with healthy, bleeding on probing, calculus, shallow pocketing of 4 or 5 mm, and deep pocketing of 6 mm or more was 3%, 4%, 23%, 59% and 11%, respectively. The mean number of sextants with healthy, bleeding, calculus, shallow pockets and deep pockets was 0.1, 0.3, 1.0, 1.3 and 0.1, respectively. Sixty-nine percent of the subjects had dentures and 60% of the denture wearers wore them day and night. Denture treatment was needed by 85% of all persons : new dentures were needed by 40% and denture repairs by 45%. Ninety percent of those interviewed had no unusual symptoms in their temporomandibular joint. Oral and denture hygiene were poor. Only 2% of the subjects were plaque-free and 20% of the denture wearers use their dentures with no visible plaque. Fifty-six percent of those interviewed had some dental complaints ; most frequently reported were difficulties with dentures and chewing. In contrast with this, 46% of the interviewed persons had a subjective need for treatment. Analysis of the results showed poor dental health in this survey group and emphasizes the necessity of improving the dental health service programs for the bedridden elderly people and also the importance of preventive programs for dental diseases in the younger generations.

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In orthodontic treatment for maxillary protrusion, markedly larger lingual displacement of the anterior teeth is necessary than for other cases, and for skeletal mandibular protrusion, surgical retraction of the mandibular bone is frequently carried out. These treatments will reduce the tongue space and cause the tongue to change its form and position, which may result in a potential constriction of the pharyngeal airway. The constriction of the airway is a serious problem in orthodontics since it has been considered to affect the dentofacial morphology or dental arch morphology inducing malocclusion. In this study, therefore, the correlation between pharyngeal airway and dentofacial morphologies was determined and the effects of the experimental reduction in tongue space on the morphological changes in pharyngeal airway were examined by lateral reontogenocephalograms. The results obtained were as follows : 1. In simple regression analyses, all the correlation coefficients found between the items in pharyngeal airway and dentofacial morphologies were not larger than 0.681 and none of the former items might be characterized by any particular single item of the latter. 2. The multiple regression analyses showed that the morphology at the upper portion of the pharyngeal airway was dependent on the variables representing downward growth of the mandibular bone. 3. When the tongue space was reduced by 5 mm as in the lingual displacement of the anterior teeth, significant changes were found in the pharyngeal airway such as the anteroposterior constriction at the middle to lower portion, the reduction in area at the middle portion, and the superioinferior extension at the lower portion. 4. The 10 mm reduction in tongue space as in the surgical retraction of mandibular bone caused significant morphological changes in the pharyngeal airway one to two times as large as those in the case of 5 mm reduction. Significant decrease was also found in the superioinferior dimension of the airway at the middle portion. The foregoing findings indicate that it may be useful for a good orthodontic performance to pay attention to the morphology of the pharyngeal airway in diagnosing and to estimate its changes by the reduction in tongue space in planning the treatment.

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Using the technique of in vivo microdialysis, extracellular concentrations of serotonin and 5-hydroxyindoleacetic acid (5-HIAA) were determined in the striatum, thalamus, dentate gyrus and prefrontal cortex while Sprague-Dawley rats underwent immobilization stress for twenty minutes. Microdialysis probes had semipermeable cellulose tubes (molecular weight cutoff 50, 000 ; O.D. 0.22 mm). Perfusion was started at 12 or 36 hours after implantation of the microdialysis probe under a freely-moving condition. Measurements of the extracellular concentration of serotonin and 5-HIAA were made at twenty minute intervals, which were started 120 minutes after the onset of the perfusion. Serotonin and 5-HIAA were quantified by a high-performance liquid chromatography coupled with an electrochemical detector. Extracellular serotonin levels increased following twenty minute immobilization stress in all four regions of the rat brain. The immobilization stress relatively increased the extracellular serotonin levels in the prefrontal cortex and dentate gyrus. These results suggest that twenty minute immobilization stress induces the activation of serotonin release in rat brain regions concerning the induction of anxiety.

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The influence of the sympathetic nervous system activity on oxygen free radicals in tooth extraction wounds was studied in dogs. Cervical sympathetic trunks were stimulated continuously in seven healthy dogs by a portable pacemaker (group S). Postcervical ganglions were permanently blocked with pure ethanol in other seven dogs (group B). Bilateral gingival blood flow was measured in both groups by the hydrogen clearance method and the laser doppler method. Bilateral mandibular premolars and molars were extracted in all dogs of both groups. Activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and concentration of lipid peroxide (LPO) in gingivas and tooth extraction sockets of all dogs were measured on the fourth day after extraction. The results were as follows : 1. Gingival perfusion significantly decreased in group S and increased in group B in ipsilateral side compared with contralateral side without any remarkable cardiodynamic changes. 2. In group S, the average levels of SOD, GSH-Px activities and LPO concentration in ipsilateral gingivas seemed to be higher than those in contralateral gingivas. The level of CAT activity in ipsilateral gingivas seemed to be the same as that in contralateral gingivas. 3. The levels of SOD and CAT activities in ipsilateral extraction sockets seemed to be lower and the level of GSH-Px activity was significantly lower than those in contralateral extraction sockets in group S. Ipsilateral LPO concentration, however, seemed higher. 4. In group B, the level of ipsilateral gingival SOD activity seemed to be lower, moreover the levels of CAT, GSH-Px activities and LPO concentration were remarkably lower than those in contralateral gingivas. 5. The levels of SOD, CAT, GSH-Px activities and LPO concentration in ipsilateral extraction sockets showed no changes, the same as in contralateral side in group B. These results suggest that ischemia occurring by hyperactivity of sympathetic nervous system accelerates the production of oxygen free radicals in tooth extraction wounds. It seems that increase of perfusion by sympathetic nerve blocks suppresses those accelerations.

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Matrix vesicles are membrane-enclosed structures that initiate mineralization in the extracellular matrix of calcifying tissues. Matrix vesicles in mineralizing tissues contain alkaline phosphatase and related phosphatase activities associated with the plasma membrane ; this may be because matrix vesicles may be the extracellular cell-membrane derived microstructures. Recently, lactate dehydrogenase isoenzymes were found to be located in matrix vesicles of the epiphyseal growth plate of young rabbit leg bones [Hosokawa et al. (1988) J. Biol. Chem. 263, 10045-10047]. In addition, lactate dehydrogenase-containing vesicles without alkaline phosphatase were found in the resting zone of the epiphyseal cartilage of young rat rib bones [Ohashi-Takeuchi et al. (1990) Biochem. J. 266, 309-312], and in the dentin of bovine tooth germs [Kitamura et al. (1991) J. Dent. Res. 70 : 1444-1446]. However, there is no report on the presence of lactate dehydrogenase-containing vesicles in the area in which intramembranous bone formation occurs. In the present study, lactate dehydrogenase-containing vesicles were found to be present in calvaria of mice and calves in which intramembranous bone formation occurs, as follows. 1. Only in the presence of detergents, lactate dehydrogenase activity was detected in the matrix vesicle fraction from the calvaria of young mice, showing that lactate dehydrogenase is located in the vesicles. 2. The matrix vesicle fraction was subjected to sucrose density gradient centrifugation. The sedimentation profiles of lactate dehydrogenase in the presence of Triton X-100 were different from that of alkaline phosphatase, showing that lactate dehydrogenase-containing vesicles were different from matrix vesicles. 3. Osteoblast fraction from mice calvaria was homogenized with isotonic solution and then subjected to sucrose density gradient centrifugation. Lactate dehydrogenase activity was recovered only in the soluble top fraction, but not in sediment, showing that lactate dehydrogenase is located only in the cytosol of osteoblasts. The result shows that lactate dehydrogenase in the vesicles is not simply encapsulated by vesicles from the plasma membranes or membranes of intracellular organelles. 4. Electrophoretic profiles of lactate dehydrogenase isoenzymes from matrix vesicle fraction of mice calvaria were identical with those of cytosolic lactate dehydrogenase of mice calvaria osteoblasts, suggesting that the presence of a mechanism for the specific uptake of cytosolic lactate dehydrogenase into vesicles. 5. Lactate dehydrogenase-containing vesicles were found to be also present in fetal calf calvaria.

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Myofunctional therapy has been in use as an auxiliary means of orthodontic treatment. A number of case presentations have been made on myofunctional therapy. Not many fundamental studies however have been made to date. Six adult subjects with good occlusion without any abnormality in the oral soft tissue therefore were selected and given lip exercise for three months to make chronological examinations of the effect of muscle training. Lip exercise was done 20 times at a time by the button pull method. The exercise was done twice a day, every day, and changes in myofunctions before, during and for two months after the training were examined. For this study, lip strength against instantaneous and sustained pulling of a strung button, integrated EMG activity under the load of weights each attached to the upper and lower lips, labial and lingual pressures on the maxillary and mandibular incisors at rest were examined about every half a month. The results were as follows : 1. Lip strength against pulling of the strung button increased significantly (p<0.05). For two months after the training, no significant changes were seen. 2. EMG activity of the upper lip against loading with weights tended to decrease and showed no significant changes for two months after the training. EMG activity of the lower lip showed various changes depending on the loads but on the whole showed decrease from 0.5 to 1.5 months after the start of the training, and tended to increase gradually for two months after the training. 3. Labial pressure at rest on the mandibular incisor increased significantly (p<0.05) by the training and decreased significantly (p<0.05) for two months after the training. Labial pressure on the maxillary incisor showed great individual differences and no significant changes were seen. Lingual pressure at rest, on the other hand, decreased significantly (p<0.05) for both the maxillary and mandibular incisors and increased significantly (p<0.05) for two months after the training. On the basis of the foregoing findings, muscle training of the lips appeared to prompt increase in muscle strength and muscle pressure of the lips and adaptation of EMG activity to the load. Lip exercise therefore was considered effective for orthodontic treatment of malocclusion accompanied by abnormality in myofunction and for prevention of relapse after treatment.

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