Many studies have reported about the toxicity of plaque and the importance of brushing for plaque control. However, patients should pause in their brushing for 7 to 10 days after oral surgery, e.g; few studies reported about plaque-induced influence in 7 to 10 days on periodontal tissue. The purpose of this study was to clarify this influence.
We selected 6 volunteers as subjects. They were without periodontal disease or systemic disease, and they had taken no medication within 1 month. No. 3 or No. 14 was selected as the subjective tooth, and the other was used as control. The subjects stopped brushing on the subjective tooth side for 1 week. We measured the following parameters : pH and bacteria flora in gingival crevicular fluid, pocket depth, and bleeding associated with probing. These measurements were done on the 1st, 3rd, 5th, and 7th days. After 7th day's measurement, subjects restarted brushing, and we measured pH, pocket depth, and bleeding 2 days later.
The results were follows : pocket depth and bleeding showed no changes in all subjects. One subject showed pH and bacteria flora changing on the 7th day. The aerobes ratio in the bacteria flora was lower than anaerobes on the 1st day and became higher on the 7th day. Although another subject showed the same bacteria flora change, the pH did not change. The other subjects showed no change in either pH or bacteria flora. These results suggested that if patients have healthy oral conditions, the stopping brushing for about 1 week evoked little change in periodontal tissue.

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The masticatory pressure through the periodontal ligament and the tensile strength of the masticatory muscles function to the mandible as the composite stress.
Using the mandible with all teeth removed from a man's body for anatomical laboratory, I examined the arrangement of the fibrous matrix constructing the bone lamellae of compact bone and bone trabeculae of spongy bone on the angle of mandible, the part of the mental foramen and the central part of the mandibular body, in which the composite stress particularly functioned, with a high-resolution scanning electron microscope. I then discussed the relationship between the stress to the bone and the arrangement of fibrous matrix and bone trabeculae.
The inner and outer layers of the angle of mandible, at which the masseter muscle and the medial pterygoid muscle are attached, were constructed by matrix fibril bundles running from infero-anterior to supero-posterior. The Haversian lamellae of compact bone of the angle of mandible were constructed by the osteons, which ran diagonally from infero-anterior to supero-posterior. The inside of the angle of mandible was constructed by bone trabeculae of spongy bone, which was arranged from infero-anterior to supero-posterior, but at the central part, that is, the part of the mandibular foramen and mandibular canal, the bone trabeculae were not examined. At the upper part of the angle of mandible, bone trabeculae were comparatively sparse, and the bone marrow space expanded slightly. The upper and lower parts of the mental foramen of the mandibular body were constructed by matrix fibril bundles running from antero-superior to postero-inferior, and the upper part was constructed by matrix fibril bundles crossing each other and running from inferior to superior. On the other hand, the Haversian lamellae were constructed by bending osteons running around the mental foramen. At the alveolar part of the second premolar of the lower jaw, that is, the part of the mental foramen, the alveolar bone proper attached to the inner and outer boards of the supporting alveolar bone, but the spongy bone around the mental foramen was constructed by the comparative sparse bone trabeculae. The upper half of the mental part on the outside layer of mandibular body was constructed by matrix fibril bundles running from supero-anterior to infero-posterior, and matrix fibril bundles crossed on the central line. The matrix fibril bundles on the mental protuberance were arranged from superior to inferior. The Haversian lamellae of compact bone on the mental part were constructed by the bending osteons running horizontally. At the alveolar part of the central incisor of the lower jaw near the mental part, the alveolar bone proper was attached to the whole inner and outer boards of the supporting alveolar bone. The mental part was mainly constructed by the bone trabeculae running to infero-posterior.

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The purpose of this study was to observe in vitro early cell attachment after 15 min and ALP activity after 11 days of cultivation of osteoblast-like cells on polished and wire-type electric discharge machined titanium surfaces with and without glow discharge treatment. Higher levels of early cell attachment were observed on both surfaces with glow discharge treatment than on those without treatment. SEM observation appeared to reveal that cells attached on surfaces with glow discharge treatment after 15 min showed better compatibility.Furthermore, ALP activity significantly improved on surfaces with glow discharge treatment of wire-type electric discharge machined titanium surfaces. These results suggested that glow discharge treatment was useful in obtaining excellent cell compatibility on a titanium surface.

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Digital radiographic systems have recently been introduced in dental practice. These systems are used with a CRT for diagnosis. But printed images may be used as reference images. The purpose of this study is to identify whether an image by the printer generally used was suitable as a reference image. A PM-770C (EPSON) was used as a printer for the digital panoramic radiography (Digipan^®). Panoramic radiographs of 17 volunteers, whose consent was obtained for this research, were obtained. Three oral radiologists evaluated them on CRT and printed images independently. Interested structures in panoramic radiograms were divided as follows : 1) contour of mandible, 2) mandibular canal and bone trabecle, 3) shape of the tooth and periodontal tissue of the mandible, 4) shape of the tooth and periodontal tissue of the maxilla, 5) bony structure of maxillary sinus. Each structure was ranked on a 5-point scale. The results of each item on a CRT image are 1.26, 1.88, 1.45, 1.62, and 1.45. Those of printed images are 1.18, 1.84, 1.75, 2.20, and 1.96. The results were not good only on the shape of the tooth and on the periodontal tissue of maxilla, suggesting that a printed image could be used as a reference image.

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The goal in the present study was to establish a rat model for estimating experimental pain in the craniofacial region. Experiments were performed on male Sprague-Dawley rats anesthetized with halothane (initial dose of 2.0% in air, maintenance dose of 0.8% in air). For pressure to the temporomandibular joint (TMJ) region, a metal bar (6 mm in diameter) was placed on the skin of the TMJ region. Pressure was delivered magnetically by rectangular pulses (1 s in duration). Electromyographic (EMG) activity of the messeter muscle ipsilateral to the site of pressure was recorded with a bipolar hook electrode. The recorded EMGs were rectified and integrated with a personal computer. The pressure of the TMJ region induced EMG activity in the masseter muscle. As the pressure increased in stages, the EMG activity also increased and finally became constant. The relation between the stimulus intensity and the magnitude of EMG activity followed a power function. The magnitude of EMG activity was significantly decreased by one administration of morphine (1.0 mg/kg, 1.5 mg/kg). These facts suggest that the magnitude of EMG activity of the masseter muscle reflects pain sensation at the TMJ region induced by pressure. This study shows that this animal model is applicable to evaluate experimental pain in the craniofacial region.

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Nd : YAG laser has recently been introduced in dental clinics to explore potential applications. However, there have been no studies to determine if this laser is suitable for clinical diagnosis of the pulp. This study was designed to evaluate the temperature rise by pulsed Nd : YAG laser at extracted teeth and to clinically determine the ability for pulp diagnosis. An output power of 2 W was used for irradiating the human enamel. The distance between the enamel surface and the laser tip was kept at 10 mm, and no absorption material was used. As an in vitro study to evaluate the thermal effect, laser irradiation was performed by using extracted teeths at 10, 20, and 30 pps, and the temperature rises at the surface (sp 1) and subsurfaces [2 mm (sp 2) and 3 mm (sp 3) from the surface] were measured by thermo-graphy after bisection. As a result, this clinical study was adopted irradiation condition of 2 W and 30 pps within 10 s. To evaluate the ability for clinical diagnosis of the pulp, we investigated the pulpal blood flow changes by laser Doppler flowmetry and the tenderness for thermal stimulation by laser at normal or inflammed pulp during and after irradiation at 2 W and 30 pps. The results were as follows :
1. A rapid increase of the pulp blood flow was found at the beginning of irradiation, and it was returned to the preoperative state soon after irradiation.
2. In normal pulp, none of the subjects complained of pain (0%), and 78.7% of them felt a warm sensation during irradiation. However, all subjects (100%) having suppurative pulpitis complained of pain during irradiation.
These findings suggested that it is possible to diagnose pulp conditions clinically by pulsed Nd : YAG laser irradiation without causing thermal damage.

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This study was carried out to determine statistical information concerning the crowns and the fixed partial dentures (total number, type and rate of crowns, number of vital or nonvital abutment teeth, for example) that were placed in outpatients in the Department of Fixed Prosthodontics at Showa University Dental Hospital from April 1997 to March 1998.
The following results were obtained :
(1) The total number of crowns and fixed partial dentures produced were 1,019; among them, crowns totaled 826 (81.1%) and fixed partial dentures 193 (18.9%).
(2) Most crowns were full-cast (421, 51.0%); the second most commonly produced was resin-faced cast (196, 23.7%); the third was porcelain-fused-to-metal (131, 15.9%).
(3) Resin-faced cast crowns and porcelain-fused-to-metal crowns were most commonly used for the anterior teeth; full-cast crowns and porcelain-fused-to-metal crowns for the premolar teeth; and full-cast crowns for the molar teeth.
(4) Fixed partial dentures in the posterior region were 61.1%; in the antero-posterior region 23.8%; in the anterior region 15.0%.
(5) With regard to the relationship between missing teeth and abutment teeth of the fixed partial denture, three-unit fixed partial dentures (one missing tooth with two abutment teeth) were most frequently treated in all regions.
(6) The crowns covered by the insurance dental service were 73.2%; the fixed partial dentures covered were 73.6%.
(7) Concerning the abutment teeth of the crowns, nonvital teeth were 83.7%; implant abutments 6.4%; nonvital teeth of the fixed partial dentures 74.4%; and implant abutments 0.6%.

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To investigate the value of anchorage in orthodontic tooth movement, we proposed the calculation method of the root surface area based on a CT image. The accuracy of this method was examined with extracted material. The root surface areas in 21 subjects were also determined from stored CT data. The ratio of area among posterior anchorage teeth and anterior teeth (incisors and canine) were calculated as a simulation of clinical tooth movement with a conventional edgewise technique. From the results, the differences between the measurements of extracted material with a high-speed three-dimensional surface detector and calculation from a 2 mm thick scanning image were demonstrated within 3%. Significant differences were found in each root surface area of all subjects. Both ratios of incisors/molars and canine/molars indicated large variations. These results suggested that the information about root surface area in individual patients gave valuable anchorage control and led to the achievement of proper tooth movement.

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The skull forms the basic structure against many competing functional demands. The skull is also related with masticatory organs, and the outlines of the nasal cavity, the orbit, and the paranasal sinuses make the ideal pillars against masticatory pressure. That is, the conductive routes of masticatory pressure are the canine pillar, the zygomatic pillar, and the pterygoid pillar. To examine the arrangement of bone lamellae of the compact bone and matrix fibril bundles of the pillar of the skull operated particularly by composite stress with mastication. I observed bone lamellae and matrix fubril bundles of maxilla with all teeth removed from a man's body for anatomical laboratory with a scanning electron microscope.
At the maxillary body on the canine pillar, the Haversian system arranged in sagittal and matrix fibril bundles on the surface were arranged in a suprero-inward direction. At the frontal process of maxilla, the Haversian system arranged in sagittal and matrix fibril bundles on the surface were arranged upward. At the glabella on which right and left canine pillars joined, the Haversian system were arranged inward to outward, and the matrix fibril bundles were arranged suprero-outward. At the frontal process of zygomatic bone on the zygomatic pillar, the Haversian system was arranged in a sagittal direction, and a comparatively big bone marrow space existed at the center. Matrix fibril bundles ran suprero-outward at the surface of the zygomatic process of maxilla and outward-superior at the zygomatic bone. The Haversian system and matrix fibril bundles of zygomatic arch on the horizontal branch of the zygomatic pillar were arranged antero-posterior. At the pterygoid process on which masticatory pressure of the last molar was conducted, the Haversian system was arranged upward to downward and the matrix fibril bundles on the surface of the outside of lateral lamina were arranged suprero-outward. In short, arrangement of the Haversian system and matrix fibril bundles on each pillar agreed with the conductive direction of masticatory pressure.
The pillar of the skull was the conductive route of masticatory pressure and joined with fibrous suture. The joining region of the pillar was composed of a saw-shaped suture of a curved suture line. The suture joined the adjacent bone with fibrous connective tissues, and connective tissues of the suture were transferred to a fibrous layer of outer periosteum. The frontal process of maxilla on the canine pillar joined the pars squamosa of frontal bone with the frontal-maxillary, and the triangular frontal sinus was divided into right and left, existing inside the pars squamosa of the frontal bone.

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We examined the effect of glow discharge treatment (GDT) on the bonding of resin composites to cp titanium plates (cpTi) by using an experimentally developed device that equipped a power source with high voltage (6.5 kV max) and high frequency (20 kHz). After the chamber was vacuumed at 0.2 Torr, GDT was performed at several treatment times in an argon gas pressure of 0.4 Torr. Since the contact angle of distilled water on cpTi with GDT for a short time decreased significantly, wettability was enhanced by GDT.
The bonding strengths of cpTi to four commercial resin composite systems for crowns and bridges were evaluated by a shear bond test. Although three products increased their bonding strength with GDT, no significant difference appeared between the products with and without GDT. This was because the bonding mechanism of the dental adhesive monomer was influenced by the adsorbed and bonding structures on the bonding surface instead of the wettability itself. These findings suggested that GDT might be useful for application to a pretreatment of cpTi for bonding resin composites, but we need more investigation on treatment conditions of GDT expecting for plasma etching effect.

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The culture-filtrate and the cell-debris fractions of a human oral flagellated protozoa, Trichomonas tenax, were examined for the degradation of sheep and human hemoglobin. The cell-debris fraction had activity to degrade hemoglobin, which was inhibited by a cysteine protease inhibitor, E-64. The degradation seemed to be due to the digestion of globin polypeptides.

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This report presents an orthognathic surgery case with severe periodontal disease. Interdisciplinary dental care was required for the subject's overall oral rehabilitation. Before to orthodontic treatment, gingival inflammation was reduced by root planing and curettage. Temporary prosthodontic treatment, oral physiotherapy, and mechanical maintenance were carried out throughout pre- and postsurgical orthodontic treatment as frequently as necessary to keep periodontium free of significant inflammation. By surgical correction, the ANB angle was improved to +2.8 degrees, from -2.7. Balanced facial profile and proper overjet-overbite were acquired without significant loss of attachment. This treatment procedure can guide clinicians in further integrating an approach that is optimal for adult patients.

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This report presents the results of a long-term care of an individual with an isolated cleft palate by a Showa University cleft palate team.
The primary palate closure was performed at 12 months of age. Orthodontic care was initiated at 4 years; thereafter the patient was put under observation for more than 10 years.
At the age of 11 years and 3 months, maxillary rapid expansion was carried out for 2 months by taking advantage of a fan-type rapid expansion, which is capable of expanding the greater amount of the anterior portion of the lateral segment, followed by retention for 3 months as the rapid expansion appliance set in place, expecting osteogenesis in the intermaxillary suture.
The unavailability of a temporary retainer after removal of the appliance, however, has an advantage of assuring how much an expanded maxillary dental arch would relapse in reference to the establishment of a treatment plan and prognostication later on. Corrective orthodontic treatment by the multibracket system was done successfully from the ages of 12 years and 3 months to 13 years and 9 months. The occlusion of the permanent teeth seems to be stable so far. Fortunately, no major problems have been found in the gnathic relationship through the growing period. The expansion of the maxillary arch was not enough to solve the arch length discrepancy. The 1st premolar on the left and the 2nd premolar on the right were selected for eventual extraction, according to the principle that extraction should not be made on the tooth expanded.

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Oral health care is significant to improving QOL (quality of life) of handicapped elderlies. Therefore it is necessary to know the oral conditions of these elderlies. This survey was performed by interviews to nurses and by oral examinations of 76 residents living in a special nursing home for the elderly opened at Ohta-ku Tokyo in April 1998.
The subjects were 9 males and 67 females. The mean ages were 75.8 for males and 81.7 for females. Most had serious illnesses, including blood circulation disease, cerebrovascular disease, and cranial nerve disease such as Alzheimer's and dementia. The numbers of edenturous persons were 26 and dentate individuals were 50. The oral hygiene of dentate persons was poor, and residual teeth suffered from dental caries or periodontal diseases. The chief oral mucous disease was atrophy of the tongue, and candidiasis was seen in a few persons. There were oral diskinesia and sounds of temporomandibular joints. The average number of residual teeth was 18.5 at the ages of 60 to 64 and decreased with aging. Comparing the relationship between oral diskinesia and the number of residual teeth, the number of teeth showed a tendency to be fewer in subjects with oral diskinesia.
These results indicate that elderlies in a special nursing home suffer from various kinds of oral diseases and systemic diseases and need oral health care.

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