The aim of this study was to investigate students' awareness of applying for the School of Oral Health Care Sciences, Tokyo Medical and Dental University and being dental hygienists in the future. Forty-seven students (2...The aim of this study was to investigate students' awareness of applying for the School of Oral Health Care Sciences, Tokyo Medical and Dental University and being dental hygienists in the future. Forty-seven students (24 first-year students and 23 second-year students) in the school answered the questionnaire including questions about becoming dental hygienists and certified social workers. We requested them to answer by recalling their thoughts at the time of application. The chi-square test and Fisher's exact test were used for statistical analysis. A significantly larger number of the first-year students thought that a dental hygienist was an attractive occupation compared with the second-year students. The time when first-year students decided to apply for the school was classified into three categories: by August, from September to December of the year preceding admission, and January or February of the admission year. The ratios of the students who decided to apply for the school were 42%, 21%, 38% respectively. The results of analyzing first-year students' questionnaire responses were as follows. A significantly larger number of students who wished or decided to apply for the school by August of the year preceding admission also applied for other dental hygiene programs. The number of students who thought that a dental hygienist was an attractive occupation was significantly greater among the students who wished or decided to apply for the school by August of the year preceding admission than among those who didn't. We consider that these students were highly motivated to become dental hygienists. It is important for the school to recruit students with high motivation.
Concomitant head and mandibular movements in mastication are thought to be regulated by sensory inputs to the stomatognathic receptors. In rats, a reflex pathway from the periodontal mechanoreceptors to the neck muscles...Concomitant head and mandibular movements in mastication are thought to be regulated by sensory inputs to the stomatognathic receptors. In rats, a reflex pathway from the periodontal mechanoreceptors to the neck muscles has been reported. However, no such pathway has been found in humans. The aim of this study was to find whether pressure stimulation to the teeth influences neck muscles in humans. The subjects were 8 healthy adults who were asked to sit in a chair with a backrest and a headrest so that the head was fixed. The upper right canine was subject to pressure by an electrical-powered stimulator in a posterior-anterior direction. The pressure was applied in a ramp-and-hold stimulation. Maximal continuous loading was 2 N with a ramp speed of 4 N/s and the stimulation interval was 5 s. The motor unit activities of the right sternocleidomastoid muscle (SCM) were recorded by needle electromyogram and analyzed as instantaneous frequency. As a result, instantaneous frequencies of activity of all 14 motor units significantly increased from 11.8 +/- 1.4 Hz before stimulation to 15.4 +/- 1.5 Hz during stimulation (p < 0.01). This result suggests that pressure stimulation to teeth induced the tonic discharge of the SCM. Therefore, there is a functional relationship between the teeth and neck muscles in humans.
The aim of this study was to develop a three-dimensional small occlusal force sensor which could be set up inside the crown of the tooth and measure both the three-dimensional occlusal force and the tooth displacement pa...The aim of this study was to develop a three-dimensional small occlusal force sensor which could be set up inside the crown of the tooth and measure both the three-dimensional occlusal force and the tooth displacement path during function at the same time in vivo. The measurement error of this occlusal force sensor was 11.9%, 8.7%, and 5.9% at maximum in the mesio-distal, bucco-lingual and colono-apical directions, respectively. The subject was a Japanese male who had good periodontal conditions and an acceptable centric occlusion. After this occlusal force sensor and tooth displacement transducer were set up at the upper left first molar, the three-dimensional occlusal force and the tooth displacement were measured simultaneously during clenching at the intercuspal position and biting a ready-made monoaxial occlusal force meter. During clenching at the intercuspal position, the tooth displaced toward the palato-disto-apical direction and this was almost the same direction in which the occlusal force acted. The difference between the values measured by this sensor and a ready-made monoaxial occlusal force meter was about 9.5% at maximum. This three-dimensional occlusal force sensor is able to reveal how occlusal force is diffused.
The purpose of this study was to elucidate the state of preparation of the dental healthcare system for a large-scale disaster in terms of health-related crisis management by public health centers (PHCs). Questionnaires...The purpose of this study was to elucidate the state of preparation of the dental healthcare system for a large-scale disaster in terms of health-related crisis management by public health centers (PHCs). Questionnaires were sent by e-mail to 549 PHCs. The response rate was 51.4%. The results showed that the percentage of preparedness for a large-scale disaster was only 26.2% and the dental healthcare system has not been constructed nationwide, especially among PHCs located in areas with smaller populations. The main reasons given for why such a dental healthcare system has not been effectively established were related to lack of concern about such a crisis and a sense that the situation is not critical. Nevertheless, PHCs have made progress in assigning dentists and dental hygienists to the dental healthcare system in preparation for a large-scale disaster.
The purpose of this research was to clarify the structural features of submandibular glands in the elderly. Submandibular glands were removed from 28 cadavers (59-96 years) which dental students had used for anatomy prac...The purpose of this research was to clarify the structural features of submandibular glands in the elderly. Submandibular glands were removed from 28 cadavers (59-96 years) which dental students had used for anatomy practice. These specimens were fixed again with 10% formaldehyde, and then paraffin sections were made from these specimens according to a general method. After Hematoxylin Eosin, Mason-Goldner, Elastica von Gieson, and Alcian Blue staining had been given, these sections were observed with a light microscope. The specimens of the elderly whom the author had used in this research were divided into two groups of the higher elderly (80 years old or more) and the lower elderly (less than 80 years old). The results were as follows: 1) Intralobular and interlobular connective tissues increase in the submandibular gland of the higher elderly. 2) The epithelial cells of the striated portion become short in the higher elderly. 3) As for the epithelial cells of the interlobular ducts, strong Alcian Blue positive reaction is observed in the higher elderly. 4) The terminal portion by which a typical form is shown decreases in the higher elderly, and the number of terminal portions decreases, too. In addition, the terminal portion generally becomes small, and the tendency of extension of the glandular cavity is observed. 5) In the lower elderly, glandular cells which react to various levels of Alcian Blue exist. Such cells are distributed almost uniformly in the lobules. However, it seems that the Alcian Blue positive cells of the higher elderly decrease. 6) It seems that these structural changes of supportive tissue, duct system, and terminal portion in the submandibular gland of the higher elderly are structural features, suggesting that the secretory function decreases.
In this study, we prepared four types of 10-mm-diameter, 10-mm-long, large, columnar, bone powder-impregnated, porous apatite blocks, which did or did not have a single nutrient channel of 1, 2, or 3 mm in diameter in th...In this study, we prepared four types of 10-mm-diameter, 10-mm-long, large, columnar, bone powder-impregnated, porous apatite blocks, which did or did not have a single nutrient channel of 1, 2, or 3 mm in diameter in the long-axis direction. We implanted them in the subcutaneous tissue of adult dogs for 4, 8, or 16 weeks, and examined the status of bone formation in each block. As a result, bone formation started with the differentiation of osteoblasts along the wall of macro-pores within an area of dense multinucleated cells, and the area of bone formation consisting of bone along the pore wall and bone marrow in the pores gradually expanded around the block in a ring fashion and inward or outward. In apatite blocks with a 2- or 3-mm nutrient channel, bone formation also proceeded along the channel in the block. At 16 weeks after implantation, even in the middle level, almost the entire porous apatite block with a 3-mm channel became the area of bone formation. However, in other apatite blocks, there remained an area without bone formation; in particular, in blocks without a nutrient channel or with a 1-mm nutrient channel, there remained an area slightly over 4 mm in diameter without bone formation at the middle level. These findings indicate the importance of the nutrient channel for good bone formation in large blocks.
Smoking has various influences on oral mucosa, including color change. We quantitatively analyzed color changes of oral mucosa by smoking. To examine the influence of smoking over a wider age range, we measured the color...Smoking has various influences on oral mucosa, including color change. We quantitatively analyzed color changes of oral mucosa by smoking. To examine the influence of smoking over a wider age range, we measured the color of oral mucosa of 62 nonsmokers and 56 smokers (age 30-83 years). We measured color with a colorimeter by a perpendicular course, illuminating the measuring sites from a distance of 1 meter by artificial sunlight. Before measuring, we used standard white for calibration. We used the CIE L * a * b * colorimetric system for the color specification. The measured sites were the lips, gingiva, tongue and buccal mucosa. Before colorimetry, we examined the precision and repeatability of colorimeter, but the change was small. Moreover, we similarly examined the sex difference and age difference, but there was no significant difference. This study was approved by the Tokyo Medical and Dental University ethics screening committee. Among nonsmokers and smokers, a statistical difference was recognized in lips L *, a *, gingiva L *, a *, and buccal mucosa L *, b *. Smoking decreased the luminosity of the lips, gingiva, buccal mucosa and caused a blue coloration of gingiva and buccal mucosa.
It is widely accepted that the sympathetic nerve activity might participate in some mechanisms underlying neuropathic pain which sometimes develops after nerve injuries. Many chemical substances have been proposed to ind...It is widely accepted that the sympathetic nerve activity might participate in some mechanisms underlying neuropathic pain which sometimes develops after nerve injuries. Many chemical substances have been proposed to induce pain sensation. Bradykinin (BK) is the most potent in exciting nociceptors and in sensitizing them to thermal and mechanical stimuli. We investigated modulatory effects of sympathetic agents on BK actions in primary afferent dorsal root ganglion (DRG) cells. The present electrophysiological experiments by using the patch clamp technique were conducted to examine the effects of noradrenaline (NA) on BK responses and to determine the sites and mechanism of interaction between them. 1. Small (diameter, 20-35 μm) DRG neurons responded to BK with inducing inward currents (BK-responses), but no BK responses could be evoked in DRG neurons larger than 35 μm . 2. NA at 10 μm augmented the BK responses in amplitude compared to the control response. 3. Clonidine at 1 μm augmented the BK responses in amplitude, but isoproterenol at 1 μm failed to augment the BK responses. 4. After pretreatment with yohimbine, the BK responses were not changed by NA. It is concluded that NA-induced augmentation of the BK actions occurred by activating alpha 2-adrenergic receptor. Furthermore, this experimental system is a useful model in order to study the cellular mechanisms of neuropathic pain.
Recently, allergy to titanium has been reported. However, the patch test reagent for titanium is not standardized yet. The form and density of the patch test reagent for titanium was changed and examined in a group of no...Recently, allergy to titanium has been reported. However, the patch test reagent for titanium is not standardized yet. The form and density of the patch test reagent for titanium was changed and examined in a group of normal subjects and a group with skin disease. The following conclusions were obtained. 1. A reagent which was composed of pure titanium powder and vaseline was not preferable because its form was a stimulant. 2. If the form of the titanium powder was not sharp even though it was not spherical, it did not cause a stimulated reaction. 3. It is suggested that TiCl4 0.1% is preferable as a patch test reagent for titanium.
Factors affecting infection are the existence of infectious microorganisms, sensitivity of hosts, number of microorganisms, and infectious routes. Efforts to prevent infection focus on not allowing these factors to reach...Factors affecting infection are the existence of infectious microorganisms, sensitivity of hosts, number of microorganisms, and infectious routes. Efforts to prevent infection focus on not allowing these factors to reach the threshold level. Inspection by an infection control team (ICT) of a hospital is one countermeasure for preventing nosocomial infection. We summarize here the problems for complete prevention of nosocomial infection based on the results of inspection by our ICT, so that staff working in the hospital can recognize the importance of preventing nosocomial infection. The following were commonly observed problems in our clinics found by the ICT : (1) incomplete practice of standard precautions and/or isolation precautions, (2) noncompliance with guidelines for the prevention of cross-infection, and (3) inappropriate management of medical rejectamenta. Infection control can be accomplished by strictly observing the standard precautions and isolation precautions. The ICT inspection round in the hospital could be an effective metaff working in the hod to clarify and overcome the problems involved in infection.
OBJECTIVES: Mass media is an important source for the general public to obtain health information. Newspapers especially have the advantages of providing a variety of information to a broad range of age groups, with wide...OBJECTIVES: Mass media is an important source for the general public to obtain health information. Newspapers especially have the advantages of providing a variety of information to a broad range of age groups, with wide regional coverage of both urban and rural areas. The purposes of this study were to review the oral malodor information in Japanese newspapers and to investigate peoples' knowledge on the causes of oral malodor. METHODS: The Nikkei Database was used to select articles published in five major newspapers over a period of 12 years from 1993 to 2004. "Oral malodor" was used as a key search word. A total of 386 articles which contained oral malodor information were identified and used for the analysis. A questionnaire survey was conducted for the patients who visited a fresh breath clinic (n=295). RESULTS: The average number of articles per year was 32.2 +/- 7.3 and there was not a significant difference among years and months. There were only 25 articles (6.5%) with the central theme of oral malodor. More than half of the articles introduced anti-oral malodor products. The causes of oral malodor were described in 35% of the articles (n=134). Periodontal disease (n=57), tongue coating (n=35), otorhinolaryngological diseases (n=19), stomach problems (n=14) and psychological factors (n=21) were described as the causes of malodor. Only 35 articles (26%) described the treatment and prevention of halitosis. According to the questionnaire survey, 39% of the patients answered that they did not know the causes of malodor. Less than half knew that oral problems were related with malodor. DISCUSSION: It was revealed that the information about oral malodor in newspapers was not enough both quantitatively and qualitatively; people had little information about oral malodor. It is suggested that dental professionals should be aware of the importance of media advocacy to provide appropriate oral health information to the public.
OBJECTIVES: The purpose of this study was 1) to obtain polygon data and individual parameters from facial photographs of Crouzon syndrome patients and general patients with malocclusion in order to synthesize facial imag...OBJECTIVES: The purpose of this study was 1) to obtain polygon data and individual parameters from facial photographs of Crouzon syndrome patients and general patients with malocclusion in order to synthesize facial images using a 3 D wire frame model, and 2) to distinguish between Crouzon syndrome patients and general patients with malocclusion using quantitative analysis of characteristic variations of facial features. MATERIALS AND METHODS: The face images were prepared from standardized full-face photographs of 10 Crouzon patients (Crouzon group) and 10 general patients with malocclusion (General group). These facial images were fitted to the 3 D wire frame model and the polygon data were obtained. Following application of principal component analysis, the individual parameters of the standard face were considered to be individual feature parameters. Linear discriminant analysis using the individual feature parameters was applied to distinguish both groups, and the validity of this statistical method was estimated. Moreover, the discriminant rates of the parts of the face were calculated and compared to those of the full face. RESULTS: A discriminant rate of 90% was obtained. The application of individual feature parameters to facial features could be used to objectively distinguish between these two groups. The discriminant rates of the part of the face were lower than those of the full face. CONCLUSION: This method seemed to be effective for diagnosing congenital anomalies from facial features. Further research on other congenital anomalies would be necessary to apply this analysis as a new diagnostic step.