Sialography is a clinical technique to take X-ray photographs of the salivary gands infused with an X-ray contrast medium. With the aim of further enhancing its diagnostic value, an attempt was made in an experimental system to analyze the factors influencing the sialographic appearances of the normal salivary glands and to investigate the anatomy and biology of the glands. A model system for an experimental sialography was established, in which the mouse parotid gland excised was photographed by microradiography after the gland was injected with an X-ray contrast medium. The mice used were mainly matured males of ICR of a random bred strain, 9 inbred strains and 5 F1 hybrid strains. The results were as follows: First, pathological sialographic apperances were produced in the normal parotid glands when an X-ray contrast medium had a large osmolarity or when it was injected at an excess rate or by an excess volume. Second, the contrast media never reached the lumens of the acini. Third, when the sialograms were obtained under the optimum conditions, the sialographic appearances differed with a strain of the mouse. It was concluded that the sialogram expressed the subtle“balance”in the filling of the gland duct system by an X-ray contrast medium, and that the“balance”reflected the genetics of the development of the parotid gland.
The presence of carcinoembryonic antigen (CEA) in minor salivary gland tumors was investigated using light and electron microscopy. Seventy eight (74.3%) of 105 cases were CEA positive. In pleomorphic adenoma and monomorphic adenoma, CEA was localized in a limited area of the specimen. In other types of tumors, CEA was either dispersed or found throughout the specimen. The predominant sites of CEA localization were the apical border of the tubular structure and the periphery of the epidermoid cell. In pleomorphic adenoma, the intercellular space of the outer cells in the two layered tubular structure was occasionally CEA positive. In the mucoepidermoid tumor, intracytoplasmic localization of CEA was frequently encountered. CEA was located on the luminal surface of the cell membrane of the tubular structure in pleomorphic adenoma and adenoid cystic carcinoma. In adenoid cystic carcinoma, CEA positive lumen of cribriform pattern showed true tubular structure. In pleomorphic adenoma, the surface of the cell membrane in squamous metaplastic lesions was also CEA positive. CEA positive outer cells of the tubular structure resembled epidermoid cells in ultrastructure. Intracytoplasmic CEA positive cells situated solitarily showed CEA reaction around the nucleus and r-ER. These findings suggest that CEA exists on the cell membrane of salivary gland tumor cells which show tubular or squamous differentiation.
The purpose of this study was to investigate the structure of the human jaw bone. Many human mandible alveolar bones were used in this study. Decalcified sections and ground sections of these materials were examined with light microscope. Especially, microradiography, scanning electron microscope and transmission electron microscope were used to examine the same region of the same ground section. In the Haversian system or the various regions of the same Haversian system, different properties appeared by light transmission, Xray absorption and staining of the decalcified section. There was an intimate correlation between the light transmission and X-ray absorption of the bone tissue; in general in the regions where the light transmission was high the X-ray absorption was low and the degree of calcification was high. In these highly calcified regions there were dense crystals and usually these could be etched easily by the acid. In the highly calcified regions, crystals were always deposited densely in the inter-collagen fibril area, the inter-fibril bundle area and the inter-collagen fiber area. The lacunae and canaliculi of these areas sometimes showed a tendency of narrowing or obstruction due to the crystals.
In order to obtain better results of apicoectomy by retrograde filling, we adopted a new operation method of apicoectomy using retrograde guttapercha filling and devised two instruments, an angle file which is used with a broach holder and a bi-angle explorer. The operation method which we adopted is as stated below : Circular gingival incision, preparation of the gingival-periosteal flap and amputation of the apical root are the same as those in apicoectomy by orthograde filling. Next, the root canal is located using the bi-angle explore and the canal debridement and enlargement are done by the use of the angle file with the broach holder. After irrigation and drying of the canal, guttapercha points are filled into the canal with or without the canals or chloropercha. Excess guttapercha points are removed and the gingival-periosteal flap is sutured to the position. Forty-three teeth were treated by this operation method. The follow-up period ranged from 6 months and 5 years and 5 months after the operation. Forty-one out of 43 teeth (95.3%) were clinically classified as successful and 2 as unsuccessful. These results revealed that the operation method we adopted is simple and the operation results are satisfactory.
The formative processes and transitional changes of the horny teeth of the lamprey (Entosphenus japonicus) were investigated from the viewpoint of comparative embryology. The horny teeth were examined by macroscopic, light and electron microscopic observation. Following results were obtained. 1. Keratohyaline granules appeared in the cells of the spinous layer later than lipid granules. Most of the keratohyaline granules were small and spherical in shape. 2. In the granular layer, the keratohyaline granules became irregular in form. These granules were associated with bundles of tonofilaments and were gradually formed a network. 3. As keratinization progressed, the cells were filled with this network, which contained bundles of filamentous components. 4. Keratohyaline was synthesized and was newly deposited in the area surrounded by the ribosomes or on the surface of the network and tubular structure where the ribosomes were attached.
Investigation was conducted to determine the correlation of the osseous ability of the bone to retain the apatite ceramics implant with the structure of the mandible and the formation of the bone around the implant. First, the tensile strength between the bone and the implant was determined by the tension test between the apatite pellets placed in the dog tibia and the bone tissue around the implant. The highest tensile strength value obtained was 65.7 kg/cm2. Second, by the push-out test of the cylindrical apatite implant placed in the dog lower jaw, the strength of the bone to retain the implant was determind. The highest extrusive strength value obtained was 300kg. Histological observation of the implant specimens under the transmission light and electron microscopes after the mechanical test indicated that the strength of the bone to ratain the implant increased in the course of time and as the bone formation advanced. Fracture caused by the mechanical strength test was found to occur inside the bone or apatite ceramics, not at the interface between the bone and the material. The push-out test and histological observation produced particularly interesting results clinically : the strength of the bone to retain the implant depended greatly on the volume of the newly formed bone one month after the implantation and on the structure of the mandible afterward.
It was reported by the author that the porous apatite could be an effective artificial bone. This time, for the purpose of investigating the clinical use of the porous apatite in the oral and maxillof acial area, experiment on implanting the material in the mandible was made. Two months after extracting the P3, P4 and M1 from the adult dog mandible, bone defects each 20 mm mesio-distally long and about 15 mm deep were produced with the underlying mandibular margin left intact. Into each defect, the porous apatite (porosity rate: about 700) was implanted from the inside of the oral cavity. Dogs were sacrificed after one week to 24 months and the examination of the tissue specimens obtained indicated : After one week, bone formation begins on the surface of the apatite adjacent to the newly formed bone around the original bone. After three months, a large amount of bone forms inside and on the porous apatite. After six months, the compact bone forms both inside the outer marginal pores and on the outermost surface of the apatite; in almost all of the pores inside and lower border of the porous apatite a lamellar bone is formed on the wall of each pore and a large yellow bone marrow is formed inside the pore. These conditions existed till 24 months after the operation. The above results imply that the porous apatite is full of promise as a filling material for use in bone defects in the oral and maxillofacial area.
Apatite ceramics implant (A.C.I.) has received extensive animal and human investigation and its clinical success has been confirmed by histological studies. The purpose of this study was to investigate the possibility of applying the A.C.I. as an immediate endosseous implant. The experimental method consisted of drilling holes 5.0mms-7.0mms in diameter and 12mms in depth into the tooth extraction sockets (P3, P4) in adult dogs, inserting cylinder shaped A.C.I. 5.1mms-7.1mms in diameter and 16mms in length into the hole so that the A.C.I. extended 4mms above the bone surface and suturing the gingival tissue around the A.C.I.. In some cases, the gaps existing between the extraction socket wall and the A.C.I. were filled with the porous apatite ceramics grains (A.C.grains) . Histological examination of the specimens was made 1 week to 3 months after implantation. In the buccolingual sections, there were no significant histological differences between the immediate implantation and the implantation after the healing of the extraction wounds. In the mesiodistal sections of the A.C.I. without the A.C.grains, the shallow areas of the A.C.I. were surrounded by a dense connective tissue at 3 months. In the cases with A.C. grains, the bone formation areas around and on the A.C.I. were more extensive, the gingival sulcus around the A.C.I. was extremely shallow and the downward growth of the epithelial cells was minimal at 3 months.