[in Japanese]

View full abstract

The mental stress or procedures of dental treatment occasionally cause unexpectable disorders to the systemic condition of patients. The risk of systemic disorders increases further in the dental treatment of the elderly or of people with life-style-related diseases.
In this report, systemic disorders that might occur during routine dental treatment and responsiveness of a dentist to unusual disorders were summarized. Moreover, the variation of maximum blood pressure of 58 patients who received dental treatment in a hospital from January 1999 to March 2000 was investigated. As a result, the variation of blood pressure of patients with life-style-related diseases showed significantly greater changes than of patients without disease. In a comparison of patients 65 years old and upward with patients less than 65 years old, the aged group showed significantly greater changes.

View full abstract

Recently, dental patients with some diseases, such as cardiovascular diseases, diabetes, bronchial asthma, hepatic disorders, and renal failures have been increasing. This article discusses adverse drug-drug and drug-disease interactions relevant to the therapeutic agents commonly used in general dental practice : antibiotics, nonsteroidal antiinflammatory drugs (NSAIDs), and dental drug.

View full abstract

We carried out a survey for 165 outpatients with complications scheduled for dental treatment under the management of anesthetists from April 1999 to March 2000.
Of these patients, 121 had various general complications, and the other 44 were managed for reasons of relative major surgical treatment. A total of 53 patients (about 44% of the cases) had circulatory diseases; the most frequent problem was hypertension. The clinical department most commonly used was the Department of Oral Surgery.
Therefore most dental treatments were surgical operations. Systemic management, using a monitor, was performed in all cases. Intravenous sedation with propofol, midazoram, or diazepam was given to 128 cases, and a local anesthetic was used in 164. Two percent lidocaine with 1 : 80,000 epinephrine was given to 150 cases. Almost all cases were managed safely and comfortably in cooperation with anesthetists.
I gave an outline of the systemic management for patients with general complications during dental treatment on these findings.

View full abstract

[in Japanese]

View full abstract

Somatometric measurements were taken on the craniofacial area of Filipinos belonging to Sundadonty and of Japanese and Chinese belonging to Sinodonty. The migration of two Mongoloid lineages of Sundadonty and Sinodonty were deeply related to the origin of modern Japanese. The measurements were stature, head length, head breadth, head height, bizygomatic breadth, bigonial breadth, and morphological facial height accordig to the method by Martin-Seller and the morphological facial depth by Minobe et al. Craniofacial indices (the cephalic index, cephalic length-height index, cephalic breadth-height index, morphological face index, zigomatic gonial index, and morphological face depth index) were calculated from the measurements. These measurements and indices were statistically compared in relation to the three populations.
The results : With the exception of head length and morphological facial depth, the mean values of the measurements were largest in Chinese, and smallest in Filipinos. The Japanese had a significantly larger head length and morphological facial depth than the others (P<0.01). Namely, many items were noted with a mean value between the Northern Asian Chinese and the Southern Asian Filipinos. Each value showed results similar to those of the Chinese and the Filipinos, and in some instances, larger values were found in the Japanese results.
This would therefore suggest that the skull form of modern Japanese could consist of a mixture of the southern Jomon trees and northern Yayoi trees. The results of this study supported Hanihara's double structure model on the origin of Japanese.

View full abstract

The Mongoloid may be divided, if roughly classified, into two groups : one the Sinodont and the other the Sundadont. It is said that the Jomon people with Sundadont came to Japan about 10,000 years ago. Later, or about 2,000 years ago, however, the Yayoi with Sinodont came to Japan by way of the Korean Peninsula and racially mixed with the Jomon, resulting in a formation of the Japanese today with Sinodont being predominant.
We therefore prepared upper jaw plaster casts from members of three races : The first is that of Filipinos belonging to the Sundadont race; the second of Japanese belonging to the Sinodont race; and the third of Chinese closely related with the origin of the Japanese. We then took three-dimensional measurements of the upper jaw plaster casts with a laser measuring device, SURFLACER Model VMS-150R-D (made by UNISN) and analyzed results of the measurements for dental arch size and palatal depth (frontal section and sagittal section) with an image analyzer computer program, SURFACER (IMAGEWARE, INC., USA), running on a personal computer and statistically studied these findings.
As a result, the Japanese were found to be akin to the Chinese in many points related to dental arch size and to the Filipinos at the center of the frontal section and at the posterior parts of the sagittal section, both in the palate. The Japanese were found to take an intermediate position between the Chinese and the Filipinos in the width of the dental arch at the second molar tooth. And they were larger than either the Chinese or the Filipinos in both anterior dental arch length and arch chord of canine.
A summary of what has been referred to may be described as the Japanese today having dental arch size and palatal depth that represent a complicated racial mixture of factors predominantly seen in the Chinese as a northern race and the Filipinos as a southern race. Nevertheless, the Japanese are akin to the Chinese in dental arch size, showing the factors predominantly observed in the northern Yayoi race, but to the Filipino in palatal depth (at the center of the frontal section and at the posterior parts of the sagittal section), showing factors that are predominantly seen in the southern Jomon race. Moreover, it could be suggested that the Japanese, with the mouth apt to protrude, showed factors predominantly seen in the northern Yayoi race.

View full abstract

To clarify the effects of enamel matrix derivative (Emdogain : EMD) on the wound-healing processes of bone defects in rat femurs, cylindrical bone defects were formed with round bars and filled with either EMD or its carrier PGA (control). On postoperation days 7 to 30, dissected femurs were examined histologically. On days 7 and 14 new trabecular bones, which were immunoreactive for bone sialoproteins, were formed postoperatively in the medullary cavities of circular bone defects. This new trabecular bone formaiton was much more prominent in EMD-treated groups than in PGA-treated controls. BSE and μ-CT examinations also revealed that the repair of bone defects by new trabecular bone formation was significantly more accelerated in EMD-treated groups than in controls. The bone volume fraction in the medullary cavities and the internal trabecular bone architecture were clearly indicated by μ-CT analysis, and BSE analysis showed low-and high-resolution views and the calcification rate of newly formed trabecular bones. In EMD-treated tissues, osteoblastic cells accumulated around the bone trabeculae. The production of bone sialoproteins by these osteoblastic cells was clearly demonstrated by immunoelectron microscopy. Multinucleated osteoclasts, which were strongly immunostained for cathepsin K, a lysosomal cysteine protease highly expressed in osteoclasts, were also present on bone trabeculae. Our results suggest that EMD is an effective biological tool in enhancing the differentiation of bone-forming cells and resulting new bone induction and remodeling during the regeneration of long bones.

View full abstract

[in Japanese]

View full abstract

Osteoclasts, present only in bone, are multinucleated giant cells with the capacity to resorb mineralized tissues. They are derived from hemopoietic progenitors of the monocyte-macrophage lineage. Osteoblasts or bone marrow-derived stromal cells are involved in osteoclastogenesis through a mechanism involving cell-to-cell contact with osteoclast progenitors. Experiments on the osteopetrotic op/op mouse model have established that a product of osteoblasts, the macrophage colony-stimulating factor (M-CSF) 9 regulates the differentiation of osteoclast progenitors into osteoclasts. The recent discovery of osteoclast differentiation factor (ODF) /receptor activator of NF-κB ligand (RANKL) allowed an elucidation of the precise mechanism by which osteoblasts regulate osteoclastic bone resorption. The treatment of osteoblasts with bone-resorbing factors up-regulated an expression of RANKL mRNA. In contrast, TNFα stimulates osteoclast differentiation in the presence of M-CSF through a mechanism independent of the RANKL system. IL-1 also directly acts on mature osteoclasts as a potentiator of osteoclast activation. Furthermore, TGF-β superfamily members, such as bone morphogenetic proteins (BMPs), strikingly enhanced osteoclast differentiation from their progenitors and survival of mature osteoclasts induced by RANKL. These results suggest that BMP-mediated signals cross-communicate with RANKL-mediated ones in inducing osteoclast differentiation and function.

View full abstract

We developed methods to detect and identify several oral microorganisms directly from dental plaque by polymerase chain reaction (PCR) and DNA hybridization. First, species-specific PCR primers and DNA probes were designed based on the dextranase genes of cariogenic streptoccocal species Streptococcus mutans and Streptococcus sobrinus and an oral normal inhabitant Streptococcus salivarius. Second, PCR primers and DNA probes were designed based on the 16S rRNA gene of Campylobacter rectus, which is associated with periodontal diseases, and Campylobacter showae which is a species related closely to C. rectus. Third, PCR primers were designed based on the 18S rRNA genes of oral protozoan Entamoeba gingivalis and Trichomonas tenax. The PCR primers were specific to the target species, as expected, and could detect DNA as an amount as low as 0.1-1.0 pg or cells as few as 10 to 100. Direct detection from clinical samples was also efficient. Therefore, the present PCR and hybridization could provide simple and rapid detection and identification methods for those oral microorganism species.

View full abstract

Laser microdissection is a new method for the procurement of targeted cells from tissue section and has enabled the analysis of nucleic acid and protein. However, the contamination of cells, other than target cells and damage of mRNA, has become a problem, since it must adhere the target cells to thermoplastic film after dissection in the conventional laser microdissection. We developed a laser pressure cell transfer method that did not need to use thermoplastic film, and the semiquantitative analysis of the various transcriptional product in oral squamous cell carcinoma and normal mucosal epithelium in the identical sample was carried out by using this method and semiquantitative RT-PCR. As a result of this analysis, the procurement of mRNA from each sample was possible. By accumulating of cases using this analysis, it was indicated to become basic data for the establishment of objective judgment and prognostic evaluation of the cancer's malignancy.

View full abstract

Na⁺/Ca²⁺+ exchanger (NCX) catalyzes the electrogenic exchange of 3 Na⁺ for 1 Ca²⁺+ across the plasma membrane in many mammalian cells. We have previously reported that the Na⁺/Ca²⁺+ exchange activity had an important role for CSF-1-induced osteoclast differentiation. In the present study, we sought the effect of KB-R7943, a new NCX inhibitor, to confirm the role of NCX1, an isoform of NCX that imports Ca²⁺+ into the cells from extracellular in the reverse mode in osteoclast formation and activation.
Bone marrow cells were obtained from the tibiae and femur of 5-to 8-week-old male ddY mice. We used Sephadex G-10 column (G10) to remove macrophages and stroma cells. Nonadherent G10-passed cells were cultured in α-MEM containing the final concentration of 15% FBS, 100 ng/ml RANKL, 20 ng/ml CSF-1. KB-R7943 inhibited the osteoclast differentiation and bone resorption in vivo dose-dependently. Furthermore, NCX1 antisense oligo deoxy nucleotide (ODN) reduced the number of tartrate-resistant acid phosphatase-positive multinucleated cells and decreased the amount of NCX1 in protein level. Eight-week-old female ddY mice received sham operations or ovariectomy (OVX) and were fed a laboratory chow for 4 weeks following the operation. Animals were given subcutaneously 337.5 mg/kg KB-R7943 or DMSO every other day for 4 weeks. After 4 weeks of treatment with KB-R7943, the BMD in the femur of OVX group was significantly decreased compared with the sham group. However, the BMD in the KB-R7943-treated OVX group was quantitatively similar to the sham group. These results suggest that bone resorption was also blocked by treatment with KB-R7943 in vivo.
In conclusion, the activation of NCX1 plays an important role for osteoclast differentiation and activation.

View full abstract

We have been developing new fabrication systems for dental prostheses using various processing technologies that were available in the general manufacturing industry. We recently developed a computer-aided fabrication system especially for crowns. The shape of the prepared tooth model was designed as three-dimension numerical value data by using a laser displace instrument. The data of the remarkable landmark were recognized automatically by the computer. Followed by designing crowns automatically by using these points in the computer. Based on the designed data, the crowns were fabricated automatically by the numerically controlled 4-axis milling machine. In our system, both the laser digitizer and the milling machine were composed in a compact unit. In this study, we evaluated the digitizing and cutting accuracies of clinically titanium crowns. Results indicated this system could produce titanium crowns with sufficient accuracy.

View full abstract

The effect of professional care on oral hygiene and feeding functions by dental hygienists for bedridden elderly was evaluated. A total of 106 bedridden individuals were divided into three groups according to the degree of intervention by dental hygienists. Thirty-one individuals who received no intervention were classified as group A, and 34 individuals (group B) received a professional oral health care. Forty-one individuals who received both professional and functional oral health care were classified as group C. Feeding conditions were recorded by nurses. To evaluate the effect of the professional oral health care, dentists and dental hygienists assessed oral conditions and functions before, after two months, and after four months of the intervention. Each subject was scored, and the results were statistically analyzed by a chi-square test. The results were as follows : The number of subjects who have food drooling significantly increased after four months in group A (p<<0.05). On the other hand, the number of subjects who have food drooling significantly decreased after four months in group B (p<<0.01). The number of subjects whose tongue plaque decreased after two and four months of the intervention in group B (p<<0.05, 0.01). From the results of this survey, it is suggested that professional care by dental hygienists to improve the oral hygiene and feeding functions of bedridden elderly is required.

View full abstract

Objective : The purpose of this study was to evaluate the acquired acid resistance of lased enamel and dentin by Er,Cr:YSGG laser to artificial caries-like lesions, in vitro.Methods : An Er,Cr:YSGG laser was used to irradiate the enamel or dentin samples from 30 extracted human molars at 6 W (67.9 J/cm ₂) or 5 W (56.6 J/cm ²) pulse energy, respectively, with or without water mist. Samples were then subjected to 2μl of 0.1 M lactic acid solution (pH 4.8) for 24 h at 36°C. The parts per million (ppm) of calcium ion (Ca ²⁺) dissolved in each solution was determined by the atomic absorption spectrophotometry, and the morphological changes were investigated by scanning electron microscopy (SEM). Results : The lowest mean Ca ²⁺ ppm was recorded in the lased samples. SEM observation showed that the lased areas were melted and seemed to be thermally degenerated. After acid demineralization, the thermally degenerated enamel or dentin surfaces were almost unchanged. Conclusions : The results of this study suggested that Er,Cr:YSGG laser irradiation with and without water mist appears to be effective for increasing acid resistance.

View full abstract

As demonstrated by Asmussen in 1975, the effectiveness of the dentin bonding system should be evaluated by observing the wall-to-wall polymerization contraction gap immediately after polymerization of the resin composite, which was restored in the cylindrical dentin cavity. We reported that the contraction gap width increased when the dentin cavity was decalcified by the acidic dentin conditioner or the functional monomer was eliminated from the dentin bonding agent. Therefore it was possible to speculate that the bonding between the resin composite and dentin cavity wall was established by the chemical interaction between the calcium in the dentin and the functional monomer in the dentin bonding agent. Furthermore, we reported experimental dentin primers that were aqueous solutions of the methacrylate derivatives and diols. We also defined that the contraction gap formation was completely prevented by a combined application of the optimized dentin conditioner, dentin primer, dentin bonding agent, and resin composite. To obtain the complete marginal integrity, the dentin should be conditioned with EDTA. Then the cavity should be primed with experimental materials (35% glyceryl mono-methacrylate, 45% erythritol methacrylate, 45% xylitol methacrylate, 62.5% ethyleneglycol, or 45% 1, 6-hexane diol). The commercial dentin bonding agents containing the 10 methacryloxy decyl dihydrogen phosphate or 4-methacryloxy ethyl trimellitate anhydride were recommended for use. The resin composite must flow into the cavity during polymerization, though only a few commerial materials are recommended.

View full abstract

Several studies have been undertaken on the natural history of periodontal disease, but the exact nature of its progress are still unclear. The purpose of this study was to determine how periodontal conditions in the population with poor oral hygiene would change without treatment during an interval of two years. A total of 486 subjects (211 males and 275 females, aged from 14 to 44 on initial examination) in a rural area of Chengde, China, were monitored for 2 years. They have very few chances to visit dentists because of the lack of dental facilities. All subjects agreed that their dental diseases would not be treated over 2 years. Two quadrants in each subject randomly selected (right upper and left lower, or left upper and right lower), and 6 sites of each tooth in both quadrants were examined by using an NIDR probe. Two years of changes of Pocket Depth (PD) and Attachment Level (AL) were analyzed site by site, and the following results were obtained. Mean PD was gradually increased by age (male 2.37, female 2.34 at age 14-19, 2.88 and 2.44 at age 40-44). Shallow pockets of less than 4 mm at the baseline showed mostly no remarkable change during 2 years in all age groups. However, pockets over 4 mm tended to deepen in 2 years. The young group had very few deep pockets, but it was noteworthy that the deepening in two years of these pockets were greater than in those of older people. Mean AL also receded by age, but the rate was higher (0.66 and 0.64 at age 14-19, 3.24 and 2.51 at age 40-44) than that of PD. Pockets of which AL was less than 3 mm at the baseline showed mostly no change during 2 years in each group. However, AL over 3 mm at the baseline tended to recede in all age groups. The results indicate that most shallow pockets have shown no noticeable change in PD and AL at least for 2 years; however, the sites where PD is over 4 mm and/or AL is over 3 mm have more potential for further periodontal breakdown.

View full abstract

The purpose of this study was 1) to investigate complete dental arch stone casts and impressions, 2) to estimate the occlusal height reproduced by stone casts, and 3) to investigate the accuracy of stone casts made from implanted metallic models.
Stone casts and impressions were measured by using a three-dimensional measuring microscope.
The results were as follows :
1. Distortion of the impression was so slight that their reproducibility was three-dimensionally superior.
2. Arch widths and lengths on the stone casts tended to increase in number.
3. In the implanted area (ITI implant), the reference points on the occlusal screw had a different tendency with relation to the amount of distortion and direction.
4. For the angled type stone casts (IAT implant), the reference points of the remaining teeth moved to a lower position.

View full abstract

For the registration of mandibular movements in edentulous subjects, reference points are usually attached on the soft tissue over the chin. Therefore it is extremely beneficial in a clinic to know the relationship of the movement between the skin and the mandibular bone. In this study the reference points on the facial skin that had the least discrepancy with the corresponding sites on the mandibular bone were deteted.
Nine retroreflective markers were placed on the skin over the mandible of dentulous subjects. Furthermore, a marker frame on which 3 markers were arranged spatially was attached to the mandibular teeth of each subject to provide a measured value of virtual points that were indicated by a stick on which 2 markers were aligned. Markers on the facial skin (S) were located and automatically tracked by six video cameras while the mandible was being moved. The measurements of virtual points (V), which were calculated from displacement of the marker frame by using a motion capture system (Vicon 370, Oxford Metrics), were combined with the video data of the markers.
To compare contact patterns of tongue-to-palate and alveolar or maxillary dentures in edentulous patients with and without their dentures, palatograms of edentulous subjects were analyzed with and image processor during the production of sounds.
Artificial palates made of black vinyl covering the palate and alveolar ridge of the maxilla were coated with white alginate powder and inserted into the mouths of the subjects. After pronunciation of the test sounds, the tongue contact areas on the artificial palates were demonstrated by a wetting of the powder and a change in color from white to black. An image processor system was employed for averaging five samples of the same sound for each subject's. The averaged pattern of each subject's palatograms were then converted to the standardized dental arch form, added, and stored. Seventy percent of each subject's common parts were extracted from the combined palatograms of the same sound.

View full abstract

Electrolyzed water came into existence around 1987. Our department started the study on electrolyzed water right after its emergence and has promoted its application in the dental field.
Presently, electrolyzed water is aggressively applied, such as to the cleansing of extracted pulp and infected root canals, the irrigation of the inside of a periodontal pocket, the cleansing and disinfection of machines and instruments, the cleansing of the excavation caused by tooth extraction, the cleansing and disinfection of dentures, the sterilization of the inside waterway of a dental unit, the cleansing and sterilization of impression materials, and gargle.
Furthermore, this water came to be applied to uses in the medical field, such as improving atopy and cleansing and disinfecting a gastrocamera. And it has been widely applied in agriculture, industry, food, stock raising, golf course, and in other diverse field.
We are convinced that this functional water will experience a surge in popularity have a leap in the 21st century, since it has extremely excellent characteristics.

View full abstract

The number of patients with dysphagia has been rapidly increasing with the rising number of senior citizens. For screening procedures, characteristic symptoms and swallowing sounds of dysphagia patients were clarified so that a new test series for swallowing disorders has been developed.
As for instrumental techniques, new measurements of videofluorography were demonstrated, including time analysis, residue places of the bolus, and shape and movement of the epiglottis. Furthermore, an acoustic analysis of the expiratory sound immediately after swallowing and new equipment using light-emitted diode (LED) have been developed.
For management, systemic and handy assessment was established in connection with management programs. A new swallowing maneuver was also developed. Food texture suitable for patients who need special care for eating has also been clarified.
For the future, new noninvasive diagnostic instruments and new management strategies will be necessary, besides studies on how to use parenteral intake together with oral intake.

View full abstract

We succeeded in transplanting human osteogenic sarcoma into nude mice. Morphologically, the transplanted tumor showed the feature of chondrosarcoma and produced types I, II, and X collagen into a cartilaginous matrix. Recently we have established a unique cell line (USAC) with chondrocyte phenotypes from the transplanted tumor. Using this cell line, the relationship between changes in cell shape and expression of collagen mRNAs was investigated in vitro to clarify the characteristics of USAC cells.
The results revealed that type I collagen mRNA was mainly expressed in the cells at a growing to subconfluent stage, and type II collagen and type X collagen were in the cells at a subconfluent to confluent stage in a monolayer culture. To investigate the shapes of cells expressing each collagen, in situ hybridization, using spot culture. Type I collagen mRNA was detected in spindle cells at a marginal area, type II collagen mRNA was in polygonal cells at a middle area, and type X collagen was in hypertrophic cells at a central area. These results indicated that USAC cells have maintained characteristics of the original tumor.

View full abstract

To investigate the relationship between skeletal morphology and muscle function in maxillofacial complex, and for the further understanding of mastication and/or biological basis of orthodontic treatment, we have been developing new analyzing systems with the help of advanced technology. In this article, we present some results from our studies.
From the results of our first study concerned with bone density and mechanical stress generated by muscle loading, mandibular skeletal growth was affected by the muscle development. In the second study, the vector of reaction force at the condylar head calculated by moment analysis, using EMG activity and muscle-loading direction, was coincident to the growth direction. Also, from the analysis of changes in the curve of Spee during orthodontic treatment, the dental arch showed sufficient reconstruction of their position to adapt the mechanical environment. This suggested that the biomechanical simulation method, including the measurement or muscle activity and bite foree, was necessary for treatment planning. Genetic analysis applied to the prediction of mandibular growth was introduced in a third study. The DNA pattern of growth hormone receptors demonstrated a strong correlation with mandibular size in cephalometrics. A more accurate growth prediction will be possible in the future. Furthermore, a computer-assisted orthodontic diagnosis system and a corn-beam CT scan were introduced.
These computer-assisted and advanced technologies could make it useful for us to derive clinically indisposable information about mechanical conditions in the mandible and mastication functions in individual subjects and lead scientific evaluation in orthodontic diagnosis.

View full abstract

We have continually studied the characteristics of oral morphology and function in very-low and extremely-low birth-weight infants.
The findings were as follows :
(1) The width of the frontal cranium was narrow, the growth of the mandible was poor, and the area of the occiput was enlarged in the lateral cranium of low-birth-weight infants at the age of 4 years.
(2) The deciduous dental arch of low-birth-weight infants was generally small and especially narrow in posterior width.
(3) Most deciduous crown diameters were smaller in low-birth-weight groups than in the normal-birth-weight group.
(4) The occlusal table area, the buccal cusp area, and the intercusp distances in the buccolingual direction of low-birth-weight groups were more reduced than those of the normal-birth-weight group in maxillary deciduous molars.
(5) The biting pressure and masticatory efficiency of low-birth-weight groups were lower than those of the normal-birth-weight group.
(6) The incidence of enamel hypoplasia and of fused teeth was higher and the microhardness of enamel and of dentin were lower in low-birth-weight groups than in the normal-birth-weight group.
The deciduous dental arch, deciduous crown dimensions, and biting pressure of very-low and extremely-low birth-weight infants would be iufluenced by the morphological characteristics of the cranium.

View full abstract

Since its introduction in the 1980s, magnetic resonance imaging has become the preferred method for diagnosing soft tissue abnormalities of temporomandibular joint (TMJ). MR imaging is non-invasive and more accurate than arthrography. In addition, it requires less operator skill and is well tolerated by patients. We are usually taking MR images of the TMJ with the fast spin echo technique that can simultaneously obtain both T2-weighted and proton density images. The purpose of this study was to determine the utility of T2-weighted and proton density images for diagnosing the disk status in TMJ, comparing the results with those obtained by T1-weighted images. We studied 104 TMJs in 52 patients with both T2-weighted and proton density images, and 80 TMJs in 40 patients with only T1-weighted images. The joints were evaluated by two oral radiologists who looked at three aspects of the joints-disk displacement, disk reduction and disk shape-giving ratings of “good” or “fair” in each category. Ratings of “good” were significant higher in all three categories in T2-weighted and proton density images than in T1-weighted images (p<0.01). Based on these results, we conclude that T2-weighted and proton density images taken with the fast spin echo technique are useful for diagnosing the disk status of the TMJ.

View full abstract

The safety of homologous blood transfusion has recently been improved by the irradiation of donated blood and the screening of this blood for infections, including HIV and hepatitis. During the window period of this process, however, patients remain at risk of contracting an infection from infused homologous blood and other minor infections. Therefore autologous blood transfusion is practiced to minimize the risk of infection and to avoid G.V.H. D. (Graft versus host disease).
We anesthesiologists recommend whenever possible an autologous blood transfusion during oral surgery. As part of a comprehensive review of our transfusion policy in the oral surgery department, we retrospectively studied cases of patients who had received an autologous blood transfusion during oral surgery at some time from January 1991 to August 2000 at Showa University Dental Hospital. Hospital policy dictates that an autologous blood transfusion is performed whenever possible during surgical intervention for maxillofacial deformities, but it presently is not widely practiced at our hospital during malignant tumor surgery because a greater volume of autologous blood is required. To date, however, we have successfully decreased intraoperative blood loss by using hypotensive anesthesia and transfusing autologous blood whenever possible.
To optimize the prognosis for patients who receive a blood transfusion during oral surgery and to increase the number of autologous blood transfusions for patients undergoing malignant tumor surgery, we would benefit from further knowledge of the most appropriate method of autologous blood transfusion as well as known and potential limitations, and its influence on hemodynamics. Therefore we will comprehensively review the literature before revising hospital transfusion policy.

View full abstract

We, the committee of efficiency in the Department of Nursing Care at Showa University, have had some inquiries to the patients treated in our hospital extend four times in 7 years (1994 to 2000). This investigation was intended to analyze the patients' ideas about dental treatment and our nursery work. The purpose of this research was
1) To improve our service for patients;
2) To improve our efficiency;
3) To know the needs or preference of patients.
The information made it possible for us to improve many items in the hospital.
Moreover, we could gain more-contemporary data by modifying questionnaires to fit the mood of the times.
After this research, much effect from the information-oriented society was recognized.
Furthermore, the research itself worked as a motivation factor in improving the staff's service.

View full abstract

The aim of this study was to evaluate the durability of three resin-modified glass ionomer (RMGI) cements (Vitrebond, Vitremer, and Fuji II LC) as compared with a conventional acid-base glass ionomer (ABGI) cement for a restorative use (Fuji II). All specimens were stored in deionized water from one month up to one year. Compressive strength, direct tensile strength (with thermal cycling), diametral tensile strength, and fracture toughness were measured. Durability was quantitated as the reduction in strength from the highest value. ABGI cement showed brittle fracture for all periods. RMGI cement initially showed some plasticity that decreased with increased aging time. Tensile strengths of all cements measured by the diametral test were significantly higher than those measured by the direct tensile test. Because of the deformation of specimens under compression, we suggest use of the direct tensile test for an evaluation of the tensile strength of RMGI. All measured properties of the RMGI cements were greater than those of the ABGI cement during all periods. However, the reduction in properties for the RMGI cements was slightly greater than that of the ABGI cement (with the exception of compressive strength). These results suggest that RMGI cements may be more suitable restoratives because of their enhanced strength, but further investigation of the durability of these cements in stress-bearing areas is needed.

View full abstract

We morphologically measured the forms of the dental arch and palate by using the maxillary dental casts by moiré topography in adult Chinese volunteers of the Shandong districts. Consequently, the round type was more prominent in dental arches, without sex differences. The dentition length and width of the posterior teeth in the volunteers were larger than those of previous reports in regard to Japanese or Filipino volunteers. The same result was obtained in the study of dental arches; namely, the Shandong group was different from the Japanese or Filipino group in the dental arch form. The dentition length and width (especially the width) of males was larger than those of females.
The palates of males were larger than those of females.
The width-height index of females was higher and the length-width index of males was higher. In the frontal section, there were no sex differences between the heights of the canine tooth and the second premolar. The palates of the first premolar were deeper in females, but the palates of the molar were deeper in males. Generally, the form of the palates in males was more up and down than in females.

View full abstract

The bonding characteristics of eight dental luting cements (polycarboxylic acid cement and resin cement : four kinds of each) to dental metals (nonprecious or precious : two kinds respectively) were evaluated by using a newly developed tensile bond test. Tensile bond strength (TBS) to the surfaces of polished dental metals and residual cement areas (%) on the fractured surfaces were measured to evaluate bonding characteristics. TBS to dental metals produced quite different, results, depending on the kind of cement, and the TBS of resin cements were 1.0-26.3 MPa; especially SB cement showed the highest bonding strength to all metals. The TBSs of polycarboxylic acid cements were 0.5-7.1 MPa and were lower than apparently that of resin cements, with the exception of VM. Moreover, the TBSs of glass polyalkenoate cements to two precious metals were unmeasurable by bonding fractured. The TBS of nonprecious metals revealed significantly higher results than that of precious metals. That of cpTi was the highest TBS because of its stable passive oxide layer. The TBS measuring technique used in this study was capable of measuring not only TBS, but also the residual cement area on the fractured surface by means of image analysis. The secondary regression line between TBS and the residual cement area on resin cement was clearly indicated with a high coefficient of relationship (r²=0.78). These results suggest that bonding characteristics should be evaluated both by TBS and by quantitative analysis of the fractured surface as residual cement.

View full abstract

A six month observation was performed to evaluate clinically the restorations fabricated with a new concept trial composite resin. Fifty restorations were made for 28 patients (30 inlays, 6 onlays, 11 crowns, 3 laminate veneers).
The results were as follows :
1) No marginal or body fracture was observed in any restoration.
2) No attrition was observed in any restoration or opposing teeth.
3) Loss of gloss was observed in 19 restorations.
4) All patients were satisfied with the restorations fabricated with this trial composite resin.
Therefore, it is suggested that this trial composite resin is a useful material for aesthetic restorations such as inlays, onlays, crowns and laminate veneers, although this material requires some improvements to maintain the gloss of restorations.

View full abstract