-
Nagaaki SUZUKI
2005 Volume 71and72 Issue 4-1 Pages
1-6
Published: March 31, 2005
Released on J-STAGE: October 08, 2010
JOURNAL
FREE ACCESS
-
—Fitness, Flexural Properties and Bond Strength to Self-curing Resins—
Kazuhiko GUNJI
2005 Volume 71and72 Issue 4-1 Pages
7-12
Published: March 31, 2005
Released on J-STAGE: October 08, 2010
JOURNAL
FREE ACCESS
The objectives of this study were to evaluate fitness, bending properties, and bond strength of newly developed light-curing denture base resins (Eclipse, Dentsply) in contrast with conventional heat-curing denture base resins (Acron, GC) . These evaluations were performed by fitting tests, bending strength tests, and shear bond strength tests. For the fitting test, 40 resin specimens, 20 for each resin, were made on plaster models, which simulated the maxillae edentulous ridge. The gaps between resin specimens and the plaster model were measured. The bending strength tests were carried out using 16 resin plate specimens (65 × 10 × 2.5 mm) . The bending strength and elastic modulus for each denture base resin was calculated. For the shear bond strength test, self-curing resins were bonded to each resin and in total, 32 bonded specimens (20 × 4 × 2.5 mm) were made. The shear bond strength tests were carried out in order to evaluate the bond strength between the self-curing resin and each denture base resin. The results of these tests revealed that Eclipse exhibited better fitness to the plaster model, larger bending strength, and larger elastic modulus than Acron. Furthermore, the bond strength of Eclipse to self-curing resin was equivalent to that of Acron. These results suggest that Eclipse has excellent properties for application in clinical settings.
View full abstract
-
Evaluation of Smear Layer Removal
Yasue FUKUMOTO
2005 Volume 71and72 Issue 4-1 Pages
13-18
Published: March 31, 2005
Released on J-STAGE: October 08, 2010
JOURNAL
FREE ACCESS
A new irrigation technique (intracanal aspiration technique, IAT) was developed to minimize the extrusion of root canal irrigant. Fifteen instrumented canals of extracted canines were divided into one control and four experimental groups of 3 teeth each. Each root was fixed in a case and surrounded with colored saline agar to measure the meter value of the Root ZX and to evaluate the extrusion of the irrigant. In control teeth, no irrigation was performed. In Groups 1 and 2, the root canal was irrigated using IAT with an aspiration needle placed 2 or 3 mm short of the apex. In Groups 3 and 4, the root canal was irrigated in a conventional manner with a washing needle placed 2 or 3 mm short of the apex. The file folder of a Root ZX was attached to the aspiration needle in Groups 1 and 2, and to a washing needle in Groups 3 and 4. Each canal was irrigated with 9 m
l of 14% EDTA solution and 6 m
l of 6% NaClO in experimental groups, and the meter value of the Root ZX during irrigation was recorded. After the irrigation, cleanliness of the canal was evaluated using a SEM and extrusion of NaClO by discoloration of the agar.
Irrigation using IAT was more effective for removing smear layer compared to the conventional method and extrusion of the irrigant was minimized. In addition, the Root ZX measurement during IAT could monitor the extent of the irrigant in the apical canal.
View full abstract
-
Toshiyuki YOSHIDA
2005 Volume 71and72 Issue 4-1 Pages
19-27
Published: March 31, 2005
Released on J-STAGE: October 08, 2010
JOURNAL
FREE ACCESS
The mammalian skull vault consists of several membrane bones with different origins. A pair of frontal bones, which occupies the anterior part of the skull vault, is derived from cranial neural crest cells. The frontal bone primordium develops at the superciliary ridge region, then expands towards the top of the head. In this study, we investigated the growth pattern of the frontal bone primordium and the factors involved in this process.
In situ hybridization of
fibroblast growth factor receptor 2 and
Runx2, which are markers of preosteob-last, revealed that the frontal bone primordium appears around embryonic day 12.5 (E 12.5) and actively grows between E 14 and E 16. We labelled the head mesenchyme of E 13 at the superciliary ridge with DiI by ex-utero surgery and found that the labelled cells were present at the apical edge of the developing frontal bone on E 18. To elucidate the molecular basis of this formation, we cultured E 15 calvarium in the presence of recombinant human bone morphogenetic proteins (rhBMPs) ; rhBMP-2 and rhBMP-7, but not rhBMP-4, accelerated the growth of the frontal bone domain.
These results suggest that the frontal bone primordium grows intrinsically by expanding the primordium not by recruiting surrounding cells, and Bmp-2 and -7 play roles in stimulating the growth of the frontal bone primordium.
View full abstract
-
Masato SAWADA
2005 Volume 71and72 Issue 4-1 Pages
28-41
Published: March 31, 2005
Released on J-STAGE: October 08, 2010
JOURNAL
FREE ACCESS
The threshold levels of taste perception on the right and left side of the tip, root of tongue and soft palate in 60 healthy volunteers were measured by means of an electrogustometry test and a filter-paper disk taste test to confirm the following hypotheses : 1) the threshold on the tip of the tongue was lower than those of the root of the tongue and soft palate, 2) there was a different threshold level between sweet, salty, sour and bitter tastes on the tip of the tongue, 3) some personal properties influenced the person's threshold. Measured threshold levels were compared between these six locations with multiple comparisons. Factors influencing the threshold level on the tip of the tongue, thereafter, were investigated using multivariate logistic regression models. Those factors included sex, age, serological, psychological and behavioral factors. As a result, the thresholds levels on the tip of the tongue were significantly lower than the root of the tongue and soft palate. The thresholds for sweet and bitter taste on the tip of the tongue were also lower than those for salty and sour taste. Increase of age, male, serological increase of zinc and usual alcohol drinking were identified as factors of increase for several thresholds, and increase of anxiety was identified as a factor of decrease for two thresholds of four tastes (sweet, salty, sour and bitter) on the tip of the tongue in the logistic regression models. Increase of depression, mouth breathing, habitual tonus of the tongue and smoking did not appear to be influential factors.
View full abstract
-
Norihisa HIGASHIHORI
2005 Volume 71and72 Issue 4-1 Pages
42-48
Published: March 31, 2005
Released on J-STAGE: October 08, 2010
JOURNAL
FREE ACCESS
In the present study, the molecular mechanisms regulating p 21WAF1/Cipl expression by basic helix-loop-helix (bHLH) factors during cellular differentiation were investigated. The cyclin dependent kinase inhibitor p 21 plays crucial roles during differentiation of osteoblasts and myoblasts. In the osteoblastic cell line MG 63, expression of the p 21 gene has been shown to be upregulated by E 2 A factors, members of the bHLH factor family. In addition, E 2 A-dependent activation of p 21 promoter can be inhibited by another bHLH factor, TWIST. Using reporter assays with mutant p 21 promoters, a novel element was identified in the p 21 promoter, which is essential for E 2 A-dependent activation and TWIST-mediated inhibition. Interestingly, in the myoblastic cell line C 2 C 12, this sequence was not involved in E 2 A-dependent activation of p 21 expression. Gel mobility shift assays showed a specific complex of the novel p 21 promoter element with nuclear factor (s) of MG 63 cells. Complex formation was inhibited by the addition of anti-TWIST antibody. In contrast no complexes could be identified with C 2 C 12 cells. These results raise the possibility that interactions of the bHLH factors with the novel p 21 promoter element are cell type specific. This suggests a novel mechanism regulating p 21 expression.
View full abstract
-
Chinobu OKADA
2005 Volume 71and72 Issue 4-1 Pages
49-55
Published: March 31, 2005
Released on J-STAGE: October 08, 2010
JOURNAL
FREE ACCESS
Diffuse noxious inhibitory control (DNIC) is a phenomenon by which the effect of noxious stimuli is inhibited by heterotopic noxious stimulation. We investigated whether heterotopic conditioning stimuli could modify the second component of EMG activities of the biceps femoris reflex (C fiber reflex) with different levels of intensity.
Forty-two adult male anesthetized Wistar rats were divided into 6 groups with 6 or 8 rats in each. Three groups (8 rats in each group) were stimulated with 3 intensity levels of the electrical test stimuli, l . 2 T, 2.0 T, or 3.0 T (times the C-fiber reflex threshold), respectively. Conditioning stimuli (pinch) were delivered to the upper lip of each rat. Test stimuli were delivered to the digits of the hindpaw. Another 3 groups (6 rats in each group) as control groups were given similar test stimuli without conditioning stimuli.
The inhibitory magnitudes of C-fiber reflex activities between the control and lip pinch were 215.5± 105.5, 277.7±159.1, 462.3±407.9 μV ⋅ms in group 1.2T, 2.0 T, and 3.0 T, respectively. The inhibitory magnitudes of C-fiber reflex activities in group 3.0 T at pinch were significantly increased compared with group 1.2 T and 2.0 T. The present study demonstrated that the C-fiber reflexes were inhibited by conditioning stimuli with 3 different levels of test stimuli under sevofurane anesthesia. Though it has been considered that DNIC effect does not depend on test stimulus intensity, the present study suggested that DNIC effect might be affected by the intensity of test stimuli.
View full abstract
-
Tomohito YANAGISAWA, Kayoko SHINADA, Yoko KAWAGUCHI
2005 Volume 71and72 Issue 4-1 Pages
56-61
Published: March 31, 2005
Released on J-STAGE: October 08, 2010
JOURNAL
FREE ACCESS
This study investigated the oral health awareness of aesthetic problems among adolescents. In 2002, a questionnaire survey on oral malodor and teeth stains was conducted at a junior and senior high school for males in Tokyo. The subjects were 783 students.
The following results were obtained.
1. The rate of students who were concerned about other persons' oral malodor was significantly higher for the students in the senior high school than in the junior high school. The attitudes toward oral malodor varied depending on whether the target was family or friends.
2. Forty percent of junior high school students and first-year senior high school students answered that they had been conscious about their oral malodor. The rate was 60% for second- and third-year senior high school students. There was a significant difference between the two groups.
3. Thirty-five percent of the students who were conscious about their oral malodor felt some difficulties in daily life such as communication with other persons.
4. Fifty percent of the students replied that they had been conscious about their teeth stains. However, most of them felt no difficulties in daily life.
From these results, it was revealed that almost half of the junior and senior high school students had been concerned about oral malodor and teeth stains. It is necessary to provide adequate dental health education on oral malodor and teeth stains for students through school oral health promotion activities as well as in dental clinics.
View full abstract
-
Yoko YAMADA
2005 Volume 71and72 Issue 4-1 Pages
62-70
Published: March 31, 2005
Released on J-STAGE: October 08, 2010
JOURNAL
FREE ACCESS
Taste buds, the sensory end organs for the sense of taste, consist of taste sensing cells, supportive cells and basel cells. Taste bud cells are heterogeneous in terms of morphology as well as functional profiles. Although the lineage of mammalian taste bud cells is largely unknown, it is generally accepted that undifferentiated epithelial basal cells surrounding taste buds enter the taste buds to form and maintain this specialized corpuscle. To analyze taste bud formation during development, we conducted morphological observations and examined differentiation marker expression. Thickening of epithelia starts at 13 dpc foetus and immunohistochemistry against a neural marker, PGP 9.5, revealed that the change of epithelial morphology precedes neural projection observed at 14 dpc foetus. Taste sensing cells appear 6 days after birth indicated by expression of the single transduction component phospholipase Cβ2 (PLCβ2) as differentiation marker. To further investigate the maintenance and cell lineage in the taste buds in adults, we injected 5'bromo-2'deoxyuridine (BrdU) solution to young growing mice for a week. BrdU label retaining cells (LRCs) could be observed even 8 weeks after injection. LRCs were examined the differentiation by PLCβ2 and proliferative activity by Ki-67. The results suggested two possibilities. 1) Part of PLCβ2 positive cells retain proliferative activity and multipotentiality, or 2) precursor cells (stem cells) stay in the taste buds and produce at least part of the taste sensing cells through proliferation and differentiation processes.
View full abstract
-
Atsushi OHYAMA, Hiroshi NITTA, Chie SHIMIZU, Satoko OHARA, Kouji ARAKI ...
2005 Volume 71and72 Issue 4-1 Pages
71-76
Published: March 31, 2005
Released on J-STAGE: October 08, 2010
JOURNAL
FREE ACCESS
Objective : Objective Structured Clinical Examination (OSCE) is widely used to assess the core competency of dental residents. However, the educative effect of feedback in OSCE has not been fully examined. Therefore, we investigated the educative effect of formative feedback in a medical interview station.
Methods : The subjects were 51 residents in the clinical training course of our dental hospital. After completing the medical interview station, residents were individually given formative feedback by evaluators and standardized patients. Two months later, residents were asked to fill in a questionnaire about the contents of feedback and self-rating mental strain level during OSCE. Videotaped performance and feedback were reviewed by investigators to check the answers to the questionnaire.Results : Evaluators provided an average of 3.1 feedback items, and standardized patients provided an average of 1.6 feedback items for each resident. However, each resident remembered an average of 1.3 feedback items from evaluators and 0.9 from standardized patients. The lower the score of residents in the medical interview station, the more feedback items were given to residents. A significant negative correlation was found between the score of evaluators and self-rating mental strain level (Spearman ρ=-0.326, p=0.019) .
Conclusion : For effective feedback, evaluators or standardized patients should focus on 2 to 3 items of essential points in OSCE. Repetition of feedback using videotaped performance may be useful to improve communication skills for medical interview.
View full abstract
-
—Questionnaire Mail-in Survey of Alumni of the School of Dental Hygiene in Tokyo Medical and Dental University—
Naomi YOSHIDA, Keiko ENDO, Keiko KONDO, Kumiko SUGIMOTO, Kazuhiro SHIM ...
2005 Volume 71and72 Issue 4-1 Pages
77-83
Published: March 31, 2005
Released on J-STAGE: October 08, 2010
JOURNAL
FREE ACCESS
This study was conducted to investigate the career history and perceptions about dental hygiene education programs among the alumni (1952-1999 graduates) of the School of Dental Hygiene in Tokyo Medical and Dental University. A questionnaire containing demographic, practice characteristics and views on the programs was mailed to 997 alumni in 1999, and 576 alumni (57.8%) responded.
Three hundred and forty-one respondents worked as dental hygienists. The majority who responded were in clinical practice. One hundred and thirty-one of the respondents worked in private clinics, 76 in public health centers, and 72 in clinics in companies. The rate of them who worked in public health centers was much higher than the national average cited in the Statistical Report on Public Health Administration and Services.
Two hundred and ninety-one respondents reported inadequate programs. The rate of them who reported inadequate programs was significantly higher in alumni who were working than in alumni who were not. The items cited as insufficiently taught at the school were clinical practice, instrumentation, foreign language, psychology, counseling, and nursing related subjects. Thus, many alumni suggested the need for better programs and continuing education.
From these results, it was suggested that dental hygienists need to change their education programs in order to meet the present and future needs of more diversified society. This view was particularly prevalent among alumni who were working. The result showed that dental hygiene educators and dental hygienists urgently need to reconsider the professionalism of their field.
View full abstract
-
Akiko FUKUNAGA
2005 Volume 71and72 Issue 4-1 Pages
84-89
Published: March 31, 2005
Released on J-STAGE: October 08, 2010
JOURNAL
FREE ACCESS
It is known that taste sensitivities change throughout life and they decline with aging. We have also found that both detection and recognition thresholds of taste were significantly elevated in aged persons, while oral somatic sensations hardly changed. To elucidate the peripheral mechanisms of the decline of taste sensitivities with age, we first investigated age-associated changes in cell renewal of taste buds in the circumvallate papillae of ddY mice, because one of the major characteristic differences of taste receptors from somatosensory receptors is a continual turnover of cells. In addition, we examined the expression patterns of taste cell-specific proteins such as protein gene products 9.5 (PGP 9.5) and gustducin, and ultrastructure of taste buds which may change resulting from the change of turnover rate. As a reference, we also used mice in the developing stage. The rate of cell renewal was examined using 5-bromo-2'-deoxyuridine (BrdU), which is incorporated in DNA during the S-phase of cells. BrdU and the proteins were detected immunohistochemically and the ultrastructure was investigated by electron microscopy. The aged mice demonstrated a delayed cell renewal and highly vacuolated cytoplasm in taste buds, while they showed no change in PGP 9.5-immunoreactive cells and an increase in gustducin-immunoreactive cells compared with young adult mice. In contrast, the developing mice showed a higher rate of cell turnover and rapid increase of PGP 9.5- and gustducin-immunoreactive cells reaching the mature level in 3 weeks after birth. The changes observed in the present study in aged mice may be related to the decline in taste sensitivity with aging.
View full abstract
-
Tatsuya FUJIMORI
2005 Volume 71and72 Issue 4-1 Pages
90-97
Published: March 31, 2005
Released on J-STAGE: October 08, 2010
JOURNAL
FREE ACCESS
The objective of the present study was to evaluate the effect of PRP on bone healing both quantitatively and qualitatively using histomorphometrical methods in a rabbit model. The examined materials were autogenous bone, PRP alone, a mixture of autogenous bone and PRP, and whole blood (as a control) . These materials were implanted into artificial defects prepared in rabbit tibiae. The observation period was set at 1, 2, 3, and 4 weeks. All specimens were used for histologic evaluation and 2- and 4-week specimens were used for histomorphometrical evaluations. The bone quantity increased when autogenous bone was applied but the percentage of mature bone in the autogenous bone site was smaller than in the PRP applied site. The results of this study suggested that the quantity of newly formed bone increased when autogenous bone was applied, but not when PRP only was applied. However, PRP might accelerate bone maturation by activating bone remodeling. According to this study, the bone quality could be altered by the application of PRP.
View full abstract
-
Daisuke SATO
2005 Volume 71and72 Issue 4-1 Pages
98-105
Published: March 31, 2005
Released on J-STAGE: October 08, 2010
JOURNAL
FREE ACCESS
Prosthodontic treatment is difficult if the alveolar ridge is low or thin. To develop a method for alveolar ridge preservation after tooth extraction, we need an experimental model of a small animal, in which we can analyze the socket healing easily and quantitatively. The purpose of the present study was to establish such an experimental model. Ten weeks old male rats of Wistar strain were used. The edge of the right mandibular incisor was cut every three days three times and the incisor was extracted at three days after the final cut. The animals were sacrificed 0, 1, 2, 4, 8, 12 weeks after the extraction and the mandibles were dissected out. The length of the alveolar bone was measured on soft X-ray photographs and bone mineral content was measured with a dual energy X-ray absorptiometer (DEXA) . Then, transverse sections of the alveolar bone were prepared. Periodic three-times cutting of the edge of the mandibular incisor made the extraction easy. Quantitative analyses of new bone formation in the socket and the resorption of the alveolar bone were possible with soft X-ray photography and DEXA. The histological findings corresponded well with the data from the soft X-ray photos and DEXA measurements. The present results demonstrated the possibility of simple and quantitative analyses of socket healing after the extraction of rat mandibular incisors. This experimental model would be useful for developing a method to prevent atrophy of the alveolar ridge after tooth extraction.
View full abstract
-
—The Effect of Oral Rinse Containing Hialuronan—
Jizhong YUAN, Haruka TOHARA, Shinya MIKUSHI, Takashi HOSHINO, Bai YUE, ...
2005 Volume 71and72 Issue 4-1 Pages
106-110
Published: March 31, 2005
Released on J-STAGE: October 08, 2010
JOURNAL
FREE ACCESS
Japanese society is aging rapidly, and the number of elderly people is increasing, hence the number of elderly people who have some diseases or disorders is growing. Therefore, Japanese dentists have to cope with various oral symptoms along with aging. Xerostomia is one of the most common symptoms of the elderly, but there is no established treatment. We tried to use an oral rinse “Oral Wet
®” that contains hialuronan and xylitol for elderly nursing home residents and examined the effect for Xerostomia. The usage of Oral Wet
® improved hyposalivation and unpleasant oral complaints of the elderly.
View full abstract
-
[in Japanese]
2005 Volume 71and72 Issue 4-1 Pages
111
Published: March 31, 2005
Released on J-STAGE: October 08, 2010
JOURNAL
FREE ACCESS
-
[in Japanese]
2005 Volume 71and72 Issue 4-1 Pages
112
Published: March 31, 2005
Released on J-STAGE: October 08, 2010
JOURNAL
FREE ACCESS
-
[in Japanese], [in Japanese]
2005 Volume 71and72 Issue 4-1 Pages
113
Published: March 31, 2005
Released on J-STAGE: October 08, 2010
JOURNAL
FREE ACCESS
-
[in Japanese]
2005 Volume 71and72 Issue 4-1 Pages
114
Published: March 31, 2005
Released on J-STAGE: October 08, 2010
JOURNAL
FREE ACCESS
-
[in Japanese], [in Japanese]
2005 Volume 71and72 Issue 4-1 Pages
115
Published: March 31, 2005
Released on J-STAGE: October 08, 2010
JOURNAL
FREE ACCESS
-
[in Japanese]
2005 Volume 71and72 Issue 4-1 Pages
116
Published: March 31, 2005
Released on J-STAGE: October 08, 2010
JOURNAL
FREE ACCESS
-
[in Japanese]
2005 Volume 71and72 Issue 4-1 Pages
117
Published: March 31, 2005
Released on J-STAGE: October 08, 2010
JOURNAL
FREE ACCESS
-
[in Japanese], [in Japanese]
2005 Volume 71and72 Issue 4-1 Pages
118
Published: March 31, 2005
Released on J-STAGE: October 08, 2010
JOURNAL
FREE ACCESS
-
2005 Volume 71and72 Issue 4-1 Pages
119-131
Published: March 31, 2005
Released on J-STAGE: October 08, 2010
JOURNAL
FREE ACCESS
