The masticatory and prevertebral muscles of two embryos and four young including a newborn and the pouch of two mothers of the red kangaroo were examined microscopically. Furthermore, four older young of the red kangaroo were examined macroscopically to define the tooth eruption. The results obtained are as follows:
1. The initial muscle spindles are already observed in the prevertebral muscles of the newborn young of 21 mm in cranio-rump length (CRL), the number of spindles being 223 (right side) -110 (left side) in the longus capitis, 81 (r) -70 (1) in the longus colli, 31 (r) -39 (1) in the rectus capitis lateralis and 5 (r) -9 (1) in the rectus capitis anterioris.
2. The initial muscle spindles are observed in the masticatory muscles of the young of 68 mm in CRL and 28 g in body weight, which is much delayed than in the prevertebral muscles; the number of spindles being 33 (right) - 46 (left) in the masseter and 173 (r) - 187 (1) i n the temporal muscle.
3. The medial and lateral pterygoid muscles are devoid of the muscle spindles. The jaw opening muscles are also devoid of them.
4. In the frontal incisors there is seen the beginning of calcification of the dentine and enamel and in the molars there is seen the beginning of the dentinal calcification at the cuspal pulp in the older young of 125 mm in CRL and 86 g in body weight.
5. In the skin with less hair lining the inner surface of the pouch, abundant large sweat glands are well observed, especially surrounding the basal region of the nipple and in the pleat formation of the skin.
6. The lactiferous mammary gland is enlarged, the lobules being divided by the interlobular muscle fiber tissue and enwrapped by the muscular capsule. The milk is squirted by the glandular muscle contraction from the gland to the nipple, to which the baby attaches itself.
7. The musculature of the pouch wall is developed to form the sphincter muscle of the pouch orifice. The sphincter muscle would play an important role in conditioning the optimum temperature and moisture of the pouch for the naked baby inside the pouch.
8. The apocrine perfume would play an important role in guiding the blind baby on the journey to the pouch after birth and the apocrine product would also take an important part in maintaining the optimum humidity of the pouch to accommodate the baby.
9. During the long period of stay in the pouch, the masticatory and locomotive systems and their neuromuscular mechanism related to the herbivorous mastication become fully established and then the young leaves the pouch to feed on the animal's proper diet. The pouch is like an incubator for the immature baby.

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In order to elucidate cell surface molecules involved in the craniofacial morphogenesis, we adopted the development of the lens placode as a model system. We raised a rabbit antibody (anti-C1) which inhibits Ca²⁺dependent cell-cell adhesion of Cl cell, a cell line derived from the fetal rat lens epithelial tissue, and examined the effects of anti-C1 on the lens development of the rat embryos under the whole embry culture.
The rat embryos were collected from the uteri at day 11. The anti-C1 Fab fragments dissolved in Hanks saline were injected near the eye anlagen with a glass capillary of about 30 pm in diameter. The injected embryos were incubated with the whole embryo culture system for 20 hours. The preimmune rabbit Fab fragments and Hanks saline alone were also injected as controls. After incubation, most of the embryos injected with the anti-C1 Fab showed an abnormal lens development, in particular, the incomplete separation of lens vesicle from epidermis, while embryos injected with Hanks saline or control antibodies showed a complete segregation of lens vesicle.
It is suggested that the Ca²⁺-dependent cell adhesion molecule of Cl cell is the target molecule of anti-C1 which is involved in the lens development. The identification of the target molecule is in progress by raising monospecific antibodies.

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The incidence of cleft lip in CL/Fr mouse is 18-2500. The purpose of this study is to clarify the cause of cleft lip in CL/Fr mouse using whole embryo culture system which is a useful technique in studying the development of mammalian embryos in vitro.
We examined the incidence of cleft lip in CL/Fr and F₁ mouse embryo (male CL/Fr x female C57BL/6) in vitro. The embryos were explanted on day 10 of gestation (plug day=0) and were cultured during the period of primary palate formation for 40-48 hours. The non-CL (P) producing strain C57BL/6 embryos were used as control.
The cleft lip was observed in 84. 4% of the cultured CL/Fr embryos, while C57BL/6 and F₁ embryos did not show any cleft lip in utero and in vitro. The incidence of cleft lip in CL/Fr mice showed variations among litters in vtero. However, in the cultured mouse embryos, there was a little variation in the incidence of cleft lip.
These results might suggest that all embryos of CL/Fr mice have a genetic predisposition to cleft lip and that the gene (s) related to cleft lip in CL/Fr mouse is (are) recessive against the allele of C57BL/6 strain.

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In the study on the orthodontic wires, the NiTi alloy is highlighted these days. It is noticed because of the special properties, i. e; the shape memory effect and super-elasticity as well as the excellent spring-back property.
Dr. Ohura and others reported that the Japanese NiTi alloy round wire produced by Furukawa Electric Co., Ltd. has these properties.
The purpose of this study is to clarify the mechanical properties of the square and rectangular wires fabricated by this NiTi alloy for orthodontic use.
Three-point bending tests and torque tests were examined and the results obtained were as follows:
1) The square and rectangular wires showed a super-elastic property in both the bending tests and torque tests,
2) The level of the super-elasticity could be decreased by heat treatment, and
3) With the increase of the heating time, the area which showed super-elasticity shifted to the left and the longer the heating time, the less the effect on the load decrease.
By using the mechanical properties of these wires, it will be possible to manage the threedimensional tooth movement involving the torque from the early stage of orthodontic treatment.

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The occlusal plane was investigated morphologically and functionally.
First, the three dimensional positions of the mandibular teeth to the cranium (FH-plane) were measured in 43 subjects with normal occlusion and the inclination of the sagittal condyle path and the lateral incisal path was also measured in these subjects. Then the correlation between these factors and the inclination of their occlusal planes to the FH-plane was calculated.
Secondly, the EMG activity of the masticatory muscles was recorded during clenching and mastication when the occlusal planes of the 2 denture wearers were inclined about five degrees anteriorly or posteriorly from the normal situation.
The findings were as follows:
1) The steep occlusal planes were generally constructed with the mandibular teeth which positioned more posteriorly and downward to the cranium.
2) The inclination of the lateral incisal path was generally gentle in the subjects with a steep occlusal plane.
3) There was no significant correlation between the inclination of the sagittal condyle path and the inclination of the occlusal plane.
4) The EMG activity of the masticatory muscles varied by altering the inclination of the occlusal plane.

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Bone morphogenetic protein (BMP) induces the differentiation of the mesenchymal cells into the cartilage and bone. In the clinical application of BMP as a substitute for the bone graft, some carriers or substrata which can enhance the action of BMP are necessary, because it is very difficult to obtain the BMP.
In this study, the author attempted to purify the BMP from the bovine bone and to find the materials for the carrier of BMP.
The bovine demineralized bone matrix was extracted with 4M Gdn-HCI and the BMP was purified by means of gel filtration and cation ion exchange chromatography from the Gdn-HCl extracted proteins. The partially purified BMP was combined with various materials and implanted in the subcutaneous tissue of rats to assay the bone-inductive activity.
The results of the purification of BMP with ion exchange HPLC indicate the possibility that more than two proteins (Mr. 18, 000 or others) may have the BMP activity. The materials for the carrier of BMP can enhance the BMP activity, if they can provide the microenvironment which is suitable for cell differentiation and can act as the delivery system for BMP. And if we can obtain them easily like the skin atelocollagen or hydroxyapatite, they are very significant clinicaly.

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For the purpose of investigating the localization of prostaglandin E (PGE) in periodontal tissues during tooth movement (6hours-3days) by an immunohistochemical technique, the following experiments were performed:
Preliminary experiment: 1. To study the influence of fixative and decalcifying solution on PGE₂ by Enzyme Linked Immunosorbent Assay (ELISA), and
2. To observe the localization of PGE in rat uterus and kidney
Main experiment: To observe the localization of PGE induced by rat experimental tooth movement on the side of the compressed periodontal membrane, using light and electron microscopes
The results obtained were as follows:
1) The immunity of PGE₂ was not influenced by Zamboni's fixative and 5% EDTA solution.
2) The localization of PGE in the fixed uterus and kidney was nearly similar to that reported by Van Orden and Mori & Mine.
3) An intense PGE reaction could be seen in the compressed periodontal membrane after 6 12hours of tooth movement. During this period, the PGE reaction could be seen in the perivascular tissue and some of the fibroblast-like cells, and
4) These PGE-positive cells were identified as endothelial cells and fibroblasts by electron microscopic observation and the intracellular localization of PGE of these cells was observed in the the cell membrane Rough-ER, and diffusely in the cytoplasm.

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With respect to the ultrasonic diagnosis in the field of oral surgery revealing complicated anatomical forms, it is desirable to analyze each echogram after the classification of the respective diseases by region and organ. This paper clarifies the characteristics of the ultrasonograms in each disease in the respective regions and states the utility of ultrasonic diagnosis .
The subjects enrolled in this study are 222 patients on whom histopathological or clinical diagnoses were made among the 350 patients who underwent ultrasonic examinations at our department for a 3-year period from September 1983 to August 1986. The instruments used were Toshiba SAL-30A and Aloka echocamera SSD-125, employing probes of 7.5MHz, 5.0MHz and 3. 5MHz, respectively.
The characteristic echogram findings in the respective regions are as follows:
1) Cheek, zygoma and infraorbital region: The role of ultrasonotomography was considered to grasp the progress in the pathological changes and the relative positioning relationship with the surrounding organs and tissues.
2) Submandibular gland: It seemed relatively easy to diagnose the presence of sialolith in sialolithiasis by the echogram and this was regarded to be useful in the patients who could not undergo sialography.
3) Parotid gland: The degree of utility of ultrasonotomography was considered to be high and the role as a screening examination in particular seemed significant.
4) Palate: Ultrasonograms were obtained by the intraoral scan and it was possible to examine the finer regions as compared with the X-ray CT.
5) Mouth floor: This was excellent in illustrating the organs and tissues adjacent to the mucosa of the oral cavity by the intraoral scan, and the relationship between the pathological changes and the sublingual gland and mouth floor muscles was evidently illustrated.
6) Neck: The echogram of the metastatic lymph nodes was characterized by a plain border and enhancement of the back/posterior echograms. The accurate diagnosis rate of the metastatic lymph nodes by ultrasonotomography was as high as 91. 8%.

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The tooth mobility under load in five subjects with normal dentition were studied in relation to the degree of interproximal contact. The non-contact sensor system with the magnetoresistive element was applied for the measurement of the mobility of the lower teeth except the second molar in the bucco-lingual and mesio-distal direction. A force of 500g was loaded on the tooth surface at right angle to the occlusal plane using the modified force-meter. The degree of interproximal contact was simultaneously measured by the modified contact point gauge. The obtained load/ mobility curve shows two phases with and without load. The largest mobility was generally shown bucco-lingually. Each tooth indicated its own particular movement path in spite of the loading direction. The recovery time of the tooth repositioning after loading was generally delayed at the bucco-lingual loading. The mobility area of the anterior teeth was significantly greater than that of the posterior teeth. The mobility area of each tooth was correlated with the degree of distal interproximal contact. The mobility and the recovery time of tooth repositioning after loading mesio-distally correlated with the degree of interproximal contact.

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The purpose of this study is 1) to develop a telemetry system to monitor the intraoral pressure continuously without any restriction on the daily life and 2) toinvestigate the clinical application of this system.
The telemetry system consists of a battery-less intraoral unit and an external one. The electromagnetic coupling between the intraoral coil and the external one is used to supply the power to the intraoral unit and to receive the signal corresponding to the pressure of the upper central incisor region. The pressure transducer, which is 6 mm in diameter and 1 mm in thickness, is constructed from a stainless steel cantilever beam 0.08 mm thick to which the semiconductor strain gauges are cemented on both sides.
The clinical application of this system is investigated on four adult subjects. The results are as follows
1) The labial pressure of the upper central incisor is 1.5 g/cm², 10.9 g/cm² and 5.0 g/cm² at rest, at deglutition and during speech, respectively.
2) The lingual pressure of the same place is 4.0 g / cm², 19.1 g/cm² and 13.9 g / cm² at rest, at deglutition and during speech, respectively.
3) The lingual pressure is always larger than the labial pressure in the upper central incisor region.

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The major problem with the maxillofacial prostheses is the color deterioration in a relatively short time. It is considered that the lipid absorption may bring about the degradation of the material.
The purpose of this paper is to investigate the effects of the lipid on the color stability of the maxillofacial silicone rubber.
The materials in this study were DOW CORNING ^(RM) DX-4-4210 (MDX) and THACKRAY SILSKIN® Clear (SILSKIN). The samples of standard size were immersed in lipid for 24 hours and irradiated with ultravioletlight for another 24 hours. Both treatments of the samples were repeated ten times.
And then, the change in the translucency and color was measured by spectral transmittance and spectral reflectance.
The findings were as follows:
1) The lipid absorption itself brought about little changes in the samples, but the samples degenerated by the oxidation of the absorbed lipid.
2) The turbidity and contrast ratio of both materials increased greatly.
3) The color of these two materials changed remarkably. The MDX turned yellow while the SILSKIN turned cloudy.

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It had been provedt hat the facial nerve of molesc ontaineda proprioceptivefi ber element. But its projectiona reas remainedu nknown. They were here investigatedb y the Nauta method and I-IRPla bellingm ethoda nd by electronm icroscopy.
The proprioceptivaef ferentf ibers, a fter entering the pons, are dividedr ostro-caudallyi nto the shorter ascending and the longer descending roots, both running closely dorsal to the trigeminals pinal tract nucleus (TSTN. )
The ascending root takes the vertical course adjacently dorsal to the TSTN, giving off manyt erminalf iberst o it and the other dorso-medialp ontine nuclei. At the levelo f the inner genu, it turns medially to meet the facial motor root and runs to the facial motor nucleus cells bilaterally.
The descendingro ot takes the vertical coursec audallya t least downt o C3, g iving off many terminal fibers to the TSTN, and the nuclei of IXth, Xth and XIIth cranial nerves. At the level of the spinal cord, the root is divided into two and they descend bilaterally through the posterior fasciculi, p rojectingt o the posteriora nd anteriorh ornc ells.
Fromt hese results, it can bee mphasizetdh at the snoutp roprioceptivfeib ersp rojectb ilaterally to the facialm otorn ucleusa nd the cervicalm otorn eurons, t he latter composinga mono-synaptic reflex system between the snout muscles and neck muscles

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The response of the pulp to the composite resin (Clearfil F) was histopathologically investigated in 23 germ-free rats. The upper first molar pulp was exposed with a #1/2 round bur through the mesial surface of the tooth and the cavity was arranged with a #33 1/2 inverted cone bur, and the composite resin was applied to the surface of the exposed pulp. The observation period was 2, 4, 7, 10 and 14 days postoperatively.
The results indicated that the pulpal response to the composite resin was characterized by the initial weak inflammatory cell infiltration at 2, 4 and 7 days, followed by the reduced responses with evidence of newly formed calcified tissues at 10 and 14 days. However, moderate to severe circulatory disturbance was observed throughout the experimental period. From these findings, the composite resin proved to have an irritating potential on the rat molar pulp.
The germ-free rats could be used as an excellent model to investigate the exposed pulp responses to the composite resin.

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The object of this study was to investigate the relationship between the staining behavior of the carious dentin by the caries detector solution and the structural characteristics of the dentin.
Using 160 human extracted caries teeth, the ground and polished sectioned surface and the cutting surface of the caries cavities were prepared.
The surface stained by the detector solution was examined by the naked eve, reflecting light microscope, observation of the SEM and determination of the Knoop hardness. The microbial invasion was also observed.
1. The staining front was generally unclear on the sectioned surfaces.
2. The stained area on the polished surface was greater than that on the ground sectioned surface. The cutting surface extended beyond the staining front observed on the polished surface.
3. The detector staining seems to depend on the structural change of the matrix and the tubules of the dentin.
4. In the moderate degree caries lesion, the softening extended deeply in the peripheral portion. In the central portion, the softening was relatively not deep.
5. The softening front always extended beyond the staining front and the microbial invasion was far behind. 6. No microbial invasion was found at the cavity floor stained light pink.

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The purpose of this study was to investigate the most effective culturing conditions to study the process of differentiation of the taste buds (TB) and the contribution of the ganglia to it.
Small pieces of the tongue of the Wistar strain rats including the circumvallate papilla (CP) were cultured with or without the IX and X cranial ganglia. They were cultured being rocked in the humidified atmosphere of 50% O₂-45% N₂-5% CO₂ at 37.. and observed with light and electron microscope.
The CP of the 17-day-old rat fetuses were cultured with or without the ganglia, using the BM-3 medium, consisting of 50% of HamF 12+DMEM (1: 1) and 50 of fetal bovine serum, supplemented with 7, 500. μg/ml of dextrose, 50IU/ml of penicillinG, 50. μg/ml of streptomycin, 150 μg/ml of ascorbate, 5. μg/ml of insulin and 200ng/ml of NGF. At this stage the fetuses showed. E neither TB nor innervation of the epithelium of the CP. The form of the CP with an epithelial structure was maintained well with the ganglia and not well without the ganglia. A bundle of nerve fibers ran along the epithelium and innervated it. The innervated epithelial cells were discriminated from the surrounding cells. In the hydrocortisone-added (1. μg/ml) BM-3 medium, the growth of the CP was inhibited and the epithelium was highly keratinized. But in the unkeratinized part of the side of the CP, large light cells with microvilli were observed, being discriminated from the surrounding epithelial cells. These cells had some characteristics common to the type 3 TB cell. It was concluded that the culture of the 17-day-old rat fetuses using the hydrocortisoneadded (1. μg/ml) BM-3 medium was the most appropriate condition for clarifying the interaction between the epithelium and the nerves and for studying the differentiation of the TB.

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This paper describes a case of regional odontodysplasia ina 10-year-old Japanese boy who complained of swelling and pain in the upper right molar region. Radiographically, 7654; seemed to be underdeveloped and showed the so-called ghostlike appearance; reduced radiodensity, granular crowns, thin enamel and dentin, large pulp chambers, short roots and open apices. This appearance was more evident in 65 than in 74.
Histopathologic and microradiographic examination of 6 revealed that the crown was covered by an uneven hypoplastic enamel which was comprised of two different layers: one presenting a prismatic structure and the other a globular structure. The dentinal tubules run irregularly and their number was markedly reduced in the crown portion. Severely hypocalcified areas were observed in several regions of the corona dentin. In the radicular dentin, however, the dentin showed a less abnormal appearance even though there was a large area of interglobular dentin.

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