Up to now, histochemical investigations of the goblet cells found in cases of postoperative maxillary cysts (POMC) have yielded somewhat variable results, while examinations of glycoproteins have been restricted to only a few methods. Recently, lectins, which have specificity for various carbohydrate residues, have been applied for the detection of glycoproteins. However, as far as the author is aware, no studies of POMC using lectin histochemistry have been done. Accordingly, PAS-alcian blue (pH 2.5) staining was performed on POMC with special reference to goblet cells, and then lectin histochemistry was employed. The specimens examined were sixty cases of POMC, which were obtained from the Department of Oral Surgery, Nihon University School of Dentistry at Matsudo. Goblet cells appeared blue or bluish-purple, and ciliated cells and columnar cells appeared light purplish-red by PAS-alcian blue staining. The ABC method was employed for lectin staining using seven kinds of lectins, i. e., Con A, WGA, SBA, DBA, RCA-I, PNA and UEA-I. Goblet cells showed positive reactions for WGA, RCA-I, PNA and UEA-I, while ciliated cells and columnar cells were positive for Con A, WGA, SBA, DBA, RCA-I and UEA-I.

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The fine structure of the junctional epithelium (JE) was studied by electron microscopy using molars of golden hamsters aged 10 days or 5 weeks. The following conclusions were obtained :
1. Primary epithelial attachment (PEA)
The oral sulcular epithelium (OSE) adjoins the enamel organ at the top of the JE. Cells of the JE showed the same structure as those of the enamel organ at the pigmentation stage.
2. Secondary epithelial attachment (SEA)
In the cells directly connected with the adjoining enamel, the Golgi apparatus was located in the cytoplasm facing the enamel, and the rough endoplasmic reticulum was found in its vicinity. In other words, this cell type showed polarity, as in secretory cells. Cells located over the cells connected with the enamel contained small vacuoles with electron-dense material in the cytoplasm.
3. Cell division
A large number of mitotic figures were found in the basal layer and cells directly connected with the enamel of the JE, and these were very numerous in the infected JE. This finding was considered to indicate that there is a relationship between the deepening of pockets and bacterial infection.
Polymorphonuclear leukocytes (PMN) were found mostly in the intercellular spaces between ameloblasts of the PEA, and in the papillary layer of the PEA. In the SEA, PMN were found mainly in the intercellular spaces between cells connected with the enamel and those of cells containing small vacuoles, as well as in the OSE. Very occasionally, PMN infiltrated the JE through the basal lamina at its apical end.

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The enamel pigmentation of Sorex (Insectivora) is distributed over the whole of the tooth from the enamel surface to the zone of the middle enamel layer, except for some unpigmented micro-areas. With respect to the structure of the enamel, Sorex has two types of organization in the unpigmented enamel (UE) and pigmented enamel (PE); prismatic and prismless enamel or tubular and atubular enamel types. In the UE areas, the enamel prisms run in a relatively complex but systematic way. However, on the PE, the enamel prisms run almost parallel to the enamel surface.
The enamel pigmentation is caused by iron. The X-ray micro-diffraction pattern suggests that the apatite of the PE is similar to that of the UE. The electron-diffraction pattern shows that the length of the axis of PE apatite is slightly different from that of natural apatite crystallites, and many dislocations were observed in PE crystals in high-resolution electron micrographs. These results suggest that some iron atoms may be distributed not only between but also inside the crystallites. The iron content is about 8% (by weight) of the enamel, as shown by SEM electron-probe microanalysis.

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The mode of tooth attachment in the black bass was observed by scanning electron microscopy, stereoscopic microscopy and light microscopy.
The black bass had conical teeth on the lower and upper jaws and these teeth had a hinged attachment. The form of attachment between the basal dentin and the pedicle differed between the anterior hinge and the posterior hinge. In the anterior hinge the front portion of the basal dentin was free from the pedicle, which was thickened and rounded like a buttress of bone. However, in the inner part of the anterior hinge and in the posterior hinge, the fibers of the basal dentin were continuous with the pedicle.
The fibers of the anterior and the posterior hinge were collagenous, but the degree of contraction differed between the lingual and pulpal sides of the posterior hinge. These differences in the structure of the hinged attachment were adapted to its function.

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At present, the cone diameter of usual intraoral X-ray machines is approximately 7.5 cm for an exposure field. On the other hand, the size of a dental X-ray film is 41mm×31mm, so that the ratio between the area of the exposure field and that of the dental film is about 3 to 1. It would thus be possible to reduce the exposure dose by reducing the exposure field area. Furthermore, the image sharpness and contrast can be improved by reducing the degree of X-ray scatter. However, creation of a small exposure field would produce other problems such as cone-cut and retaking. Therefore, some devices such as film holders and indicators have been designed, but there is difficulty in using them in patients with mouth-opening disorders or wisdom teeth, since the holder and beam aligning unit are both in one unit. We report in this article the development of a magnetic sensor for the prevention of cone-cut.
A rotary magnetic field is generated by coils installed at the end of the cone, so that the center of rotation and the central part of the X-ray beam are on the same axis. Secondly, this center of rotation is sensed by a pair of Hall ICs (integrated circuits) which are fitted to the back of the film, and the output from these ICs is transmitted to the location detector. The location of the Hall ICs is calculated, and the result is indicated by light-emitting diodes (LED) arranged in the shape of a cross.
By using this apparatus, it has become possible to confirm that the center of the X-ray beam is vertical to the center of the film when taking dental X-rays. Accordingly, this apparatus facilitates a considerable reduction of the exposure field and also prevents cone-cut.

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Isolated and delayed zygomatic arch fracture presents as a depression on the side of the face. The majority of zygomatic arch fractures are stable when reduced because of interdigitation of the bone ends and because the fragments are held in a vertical plane by the temporal fascia above and by the masseter muscle below. Occasionally, however, arch fractures are unstable and require active fixation. A case is described in which circumferential wires tied over a self-curing acrylic bow on the face were used for the fixation of a delayed zygomatic arch fracture.

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A bone autograft obtained from the iliac crest was implanted into the periodontal region of the lower first molar (36) in a patient suffering from juvenile periodontitis. In the present paper we describe the results of a biopsy obtained 5 years after the graft implantation. The radiological, histological and ultrastructural images obtained suggested that neoformation of bone, cementum-like tissue, and of connective tissue interposed between the two, had occurred.

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