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Dental hygiene students find it challenging to understand and perform the dental hygiene process of care (DHPC) after only a limited amount of clinical training; they generally improve their DHPC skills through clinical experience after graduation. In this study, we developed and evaluated interactive learning materials that simulate the DHPC. We divided the learning contents of the DHPC into six components and created five simulation materials. Using these materials, students could experience a typical DHPC virtually. In total, 30 third-year university dental hygiene students were divided into two groups (A and B), and then pre-quizzes were carried out for each group (group A: Quiz I, group B: Quiz II). Next, the students learned using the developed materials and took post-quizzes (group A: Quiz II, group B: Quiz I) to clarify their understanding of the DHPC. After the post-quizzes, a questionnaire survey was conducted. Both groups showed significantly higher scores on the post-quiz than on the pre-quiz (Group A: p = 0.0451 vs. Group B: p = 0.0090, paired Student’s t-test). In addition, more than 80% of the responses to the questionnaire were favorable. These results suggest that the simulation materials developed in this study are effective for learning the DHPC.

INTRODUCTION Insufficient educational resources on sports dentistry result in varying lecture implementations across dental schools, which cause knowledge gaps amongst students. Thus, a new interactive sports dentistry-related computer-assisted learning (CAL) module was created to facilitate dental school undergraduate students' education. This study compared the CAL module's learning effectiveness with conventional video lectures (VL) and assessed its effectiveness when used over several years at a university, and examined its validation in different university contexts, and students' perceptions. MATERIALS AND METHODS Participants were 305 fifth-year students. Students from a university in Tokyo participated for 3 years and those from a university in Saitama for 1 year. In each year, the students were divided into two groups-CAL and VL. They studied their assigned modules in 20-min lessons. A written test was administered to determine their knowledge acquisition levels, along with a questionnaire. RESULTS Two hundred sixty-two consenting participants were included in the statistical analysis. The CAL groups' test scores at both schools were significantly higher than the VL groups' every year (p

Objective The purpose of this study was to develop and evaluate the effectiveness of using e‐learning on smartphones to provide dental hygiene education on dental treatment procedures. Methods This was a randomized controlled trial. Two‐hundred ninety‐three dental hygiene students in four universities, one junior college and one technical school took a preliminary examination, and based on the results, participants in each school were randomly divided into two groups, a test or control group. Both groups took pre‐ and post‐examinations at a 4‐week interval. The test groups learned dental treatment procedures and four‐handed techniques with interactive learning materials using smartphones. The learning materials allowed them to watch videos of dental treatments. The control groups were not provided any learning material. Results Results of all schools combined showed that the changes from pre‐ to post‐examination scores in the test groups were significantly higher than those of the control groups (p

Objective Dental students follow different academic performance trajectories in response to increasing study load, based on individual and school factors. Group-based trajectory modeling is useful for clarifying the underlying trajectory patterns of students' academic performance and its determinants. To our knowledge, no studies have used group-based trajectory modeling to examine the effects of individual and school factors on academic performance trajectories in dental students. The objective of this study was to examine the effects of individual and school factors on academic performance trajectories in Japanese dental students using group-based trajectory modeling. Methods The analytical sample consists of 103 dental students admitted to Tokyo Medical and Dental University, Tokyo, Japan, in 2013 and 2014. Students' academic performance was assessed by biannual grade point average (GPA) score and GPA in the preclinical phase (second to fourth grade) was used for this study. We used group-based trajectory modeling to categorize students' GPA trajectories into different groups. A multinomial logistic regression model was fit to examine associations between students' individual and school factors, and odds of being assigned to certain GPA groups. Results GPA trajectories of dental students were classified into 4 different groups. Students' past academic performance in high school was associated with lower GPA trajectories and withdrawal or repeating years. Males were significantly associated with lower GPA trajectories and withdrawal or repeating years, even after adjusting for past academic performance. Conclusions Past lower academic performance and being male were positively associated with lower academic performance trajectories in Japanese dental students.

Critical thinking is recognized as an essential aspect in the training of healthcare professionals, yet it has not been explicitly applied to dental education in Thailand. Therefore, this research study aimed to survey the status of critical thinking disposition among Thai dental students and examine the correlation between critical thinking disposition and academic performance.In 2020, 322 students from a Thai dental school were invited to participate in the study and answer an online questionnaire supplying demographic data and Grade Point Average (GPA), and respond to the California Critical Thinking Disposition Inventory (CCTDI). A one-way analysis of variance and Spearman's correlation were used to analyze the data.Overall, 279 of the 322 participants (86.6%) completed the demographic information and CCTDI. Three subscales were found to be in the ambivalent range: truth-seeking (36.8 ± 6.2), systematicity (39.0 ± 5.5), and maturity of judgment (37.1 ± 5.9). Most of the CCTDI subscale scores did not significantly correlate with GPAs, except for systematicity (r = 0.119, p = 0.047) and confidence in reasoning (r = 0.146, p = 0.015).This study examined the strengths and weaknesses of the students' critical thinking dispositions. Their GPAs correlated with two critical thinking disposition subscales; however, the results did not guarantee a correlation with academic outcomes. Pedagogical strategies to develop dental students' critical thinking dispositions need to be further assessed.

The aim of this study was to evaluate the effectiveness of a dental model in training, evaluation, and standardization of examiners in pocket probing and to determine the appropriate thresholds of accuracy and measuring time when using this model for evaluation of probing skills without measuring patients' pockets repeatedly. In 2011-12, a total of 66 dental professionals and 20 dental students in Japan measured the probing depths of 24 artificial teeth using the six-point method on a dental model. All examiners measured the probing depths of six tooth groups and then checked the correct depths in each group. Each examiner measured four groups in a group-by-group manner. For each group, the measuring time and examiner's accuracy were recorded. Receiver operating characteristic (ROC) curves for various thresholds of measuring time were drawn for thresholds of accuracies to determine the passing mark as a skilled examiner. The accuracy significantly increased from the first to the fourth measurements, and the measuring time was significantly reduced for both the professionals and students. The total measuring time was significantly longer for the students than the professionals. The students' accuracy was significantly lower than that of the professionals in the first measurement group. The increasing rate of accuracy was significantly higher for the students than the professionals. These results and ROC curves suggested that the dental model is effective for periodontal pocket probing training and for the evaluation and standardization of examiners' probing skill at a preclinical level. An examiner having accuracy ≥80% within four minutes for six tooth measurements in this model could be considered a skilled examiner.

Reduction in alveolar ridge volume is a direct consequence of tooth extraction. Tunnel β-tricalcium phosphate (β-TCP) blocks were manufactured from randomly organized tunnel-shaped β-TCP ceramic. Efficacy of these blocks compared to extraction alone for alveolar ridge preservation after tooth extraction with buccal bone deficiency was evaluated.Maxillary first premolars of six beagle dogs were extracted after removing the buccal bone, and bone defects of 4 × 4 × 5 mm (mesio-distal width × bucco-palatal width × depth) were created. Fresh extraction sockets with buccal bone defects were filled with tunnel β-TCP blocks at test sites. Two months after the operation, histologic and histometric evaluations were performed.Regarding histologic sections, coronal and middle horizontal widths of the alveolar ridge were significantly greater at test sites (3.2 ± 0.5 and 3.6 ± 0.4 mm, respectively) than at control sites (1.2 ± 0.3 and 2.0 ± 0.6 mm, respectively). The amount of woven bone was significantly greater at test sites (62.4% ± 7.9%) than at control sites (26.8% ± 5.3%), although that of connective tissue and bone marrow was significantly greater at control sites (38.1% ± 6.2% and 16.0% ± 6.9%, respectively) than at test sites (10.7% ± 5.7% and 4.1% ± 2.2%, respectively). Regarding basic multicellular units, no statistically significant difference was found between the test and control sites (0.5% ± 0.1% and 0.6% ± 0.1%, respectively).Tunnel β-TCP blocks represent an effective bone-graft material for alveolar ridge preservation in fresh extraction sockets with buccal bone defects.

Background Group-based trajectory modeling is a useful tool for categorizing students’ academic trajectories and their determinants. Using insights gained from the analyses, we can identify students at risk for poor academic performance and monitor them to provide support. To date, studies investigating the associations between demographic factors and academic performance trajectories among medical students are scarce. The study objective was to examine the associations between demographic factors and academic performance trajectories in medical students using group-based trajectory modeling. Methods Participants included all medical students admitted to Tokyo Medical and Dental University in Japan in 2013 and 2014 (n = 202). Academic performance was evaluated by biannual grade point average (GPA) scores in preclinical years. We used group-based trajectory modeling to categorize students into GPA trajectories. Multinomial logistic regression was used to examine the association between the odds of being in a certain GPA trajectory group and demographic factors such as high school type, high school geographical area, admission test type, high school graduation year, whether the student was a biology major, and sex. Results Students’ GPA trajectories were classified into four trajectory groups as well as another group that consisted of students who withdrew or repeated years. We found that students whose high school geographical area was outside the National Capital Region were 7.2 times more likely to withdraw or repeat years in comparison with students whose school was inside the National Capital Region (OR: 7.21, 95% CI: 1.87, 27.76). In addition, admission test type, high school graduation year, and sex were associated with GPA trajectories. Conclusions High school geographical area, admission test type, high school graduation year, and sex were associated with GPA trajectories. These findings provide important insights into identifying students at risk for poor academic performance and strategies for monitoring them to provide adequate and timely support.

With the development of technology, the knowledge and skills needed to become a dentist are increasing. Computer-assisted simulation learning materials have been utilized for dental education because of their high efficiency and efficacy. However, it is not well understood which material design is strongly associated with an education effect. We therefore investigated the effects of interactivity with learning materials on learners' knowledge acquisition, memory retention, and anxiety reduction. Learning effects and degree of anxiety were compared between dental residents who learned using an interactive-type material, which required decision making and provided feedback (Group I, n=26), and those who learned using a display-type material, which merely displayed the appropriate action on a computer screen (Group D, n=23). Quiz scores immediately after learning and 3 weeks later were significantly higher in Group I than those in Group D (p0.001 and 0.016, espectively). Regarding anxiety, state anxiety after learning with interactive material was significantly decreased in Group I (p0.05), whereas no significant change was observed in Group D. Our results suggest that interactivity with computerassisted simulation materials is more effective for knowledge acquisition, memory retention, and anxiety reduction.

The aim of this study was to examine the effectiveness of interactive simulation materials with decision making in knowledge acquisition and anxiety reduction. Dental students in their fourth year at Tokyo Medical and Dental University were randomly divided into Groups I and D. Participants read a scenario, learned with interactive-type (Group I) or display-type (Group D) learning materials about pulpectomy, and took the State-Trait Anxiety Inventory-JYZ, a quiz for measuring learning effects, and a questionnaire for evaluation of the material. Except for requesting decision making in the interactive-type material, the contents of both materials were the same. The results were compared using the unpaired Student's t-test, Fisher's exact test, and the two-way repeated measures ANOVA with the Bonferroni post hoc test. The mean quiz score was significantly higher in Group I than in Group D (I: 75.4±1.4, D: 60.6±2.7, p0.001). There was no significant correlation between the groups and the responses except for one question about operability (p0.05). A significant main effect on state anxiety was found between examination points (p0.001), and state anxiety significantly increased after reading the scenario (p0.001) and reduced after learning (p0.001). Interactive simulation materials with decision making might be effective in knowledge acquisition.

Background and Objective Tissue regeneration is affected by the porosity, chemical properties and geometric structure of graft materials. Regeneration of severe periodontal defects, such as one-wall intrabony defects, is difficult because of reduced tissue support, and bone grafts are commonly used in such cases. In the present study, a tunnel-structured β-tricalcium phosphate (tunnel β-TCP) graft material designed to stimulate bone formation was fabricated. The objective of this pilot study was to evaluate the effect of this graft material on periodontal regeneration in one-wall intrabony defects in dogs. Material and Methods Six male beagle dogs were used in this study. First, the mandibular second and third incisors were extracted. Experimental surgery was performed 12 wk after tooth extraction. Bilateral 4 × 8 mm (width × depth) one-wall intrabony defects were created in the mesial side of the mandibular canines. At the experimental sites, the defects were filled with tunnel β-TCP, whereas the control defects were left empty. Twelve weeks after surgery, qualitative and quantitative histological analyses were performed. Results There were no signs of clinical inflammation 12 wk after surgery. Coronal extension indicative of new bone formation was higher at the experimental sites than at the control sites, although the differences between both the sites in the newly formed cementum and connective tissue attachment were not significant. Newly formed periodontal ligament and cementum-like tissue were evident along the root surface at the experimental sites. The inner surface of the tunnels was partially resorbed and replaced with new bone. New blood vessels were observed inside the lumens of tunnel β-TCP. Conclusion Tunnel β-TCP serves as a scaffold for new bone formation in one-wall intrabony defects.

Dental and dental hygiene students must acquire the skill of measuring periodontal pockets and learn to identify the bottom of a pocket, especially of deep periodontal pockets. A new dental model that would enable students to practice measuring deep periodontal pockets was developed at the Tokyo Medical and Dental University. The purpose of this study was to evaluate the feasibility and effectiveness of this model. Twenty dental hygiene students in their third year at the school and twenty-four instructors or dental hygienists of the University Hospital measured periodontal pockets on the newly designed dental model. Feasibility and effectiveness of the model were evaluated based on periodontal probing by the students and instructors, as well as results of a questionnaire. The results demonstrated an intraexaminer agreement (within ±1 mm) averaging 91 percent. The mean percentages of correct answers of the students and instructors were 82 percent and 80 percent, respectively. More than 90 percent of the instructors and students reported that the new model would be suitable for pocket probing training. In the questionnaire, they responded that this practice using the new model would contribute to students' future and that they wanted to try other dental models with various probing depths. The new dental model designed for periodontal pocket probing training was reported to be feasible and effective for student practice.

A live broadcasting system was developed as part of dental education with Information and Communication Technology (ICT) at Tokyo Medical and Dental University. The purpose of this study was to utilize this system in complete denture prosthodontics, especially for the procedure of making a definitive impression with custom tray border molding in edentulous patients, and to evaluate its effectiveness. Live broadcast lectures on complete denture prosthodontics were given to fourth-year students in 2009 (fifty-nine students) and in 2010 (sixty-five students). To evaluate this lecture, a questionnaire was distributed to the students and faculty members after the lecture. Almost all the students and faculty members rated the lecture as good. Students commented that the lecture was "intelligible," "inspiring," "improved understanding," "good because they could ask questions in real time," "helped to know the actual time," "good for all the students to see the same case," and "close to real experience and induced a sense of tension." The results of this study suggested that a live broadcast lecture would help students experience the real clinical situation and aid in teaching complete denture prosthodontics.

We theoretically investigate the self-adjustment mechanism of the threshold voltage shift of the static random access memory (SRAM) based on the double-floating-gate (DFG) structure by considering the capacitive coupling between the neighboring DFGs. We numerically show that the threshold voltage shift is enhanced by the interference between DFGs through the capacitive coupling. The static noise margin of DFG-SRAM is analytically estimated and expected to increase by more than 50% at 0.5-V operation.

Clinical reasoning competency is essential for an appropriate clinical dental treatment. Among the tools for the assessment of clinical reasoning competency, computer-based testing (CBT) is considered more useful than paper-based testing (PBT), because teachers can control the timing of information given to the examinees. Such timings could possibly affect the thinking process of examinees. However, few studies reported differences of reasoning between the two testing modes. In the present study, we developed an assessment of clinical reasoning and applied it using CBT and PBT to compare the examinees' performance. The participants comprised 60 students in the fifth-year class in 2012 of the School of Dentistry, Faculty of Dentistry, Tokyo Medical and Dental University. The tests comprised 25 problems, each with four questions, totaling 100 questions. The contents of the questions were the same in CBT and PBT. The students were assigned to CBT (Group C, n = 30) and PBT (Group P, n = 30) groups, with an almost equal gender ratio in the groups. The difference between scores was analyzed with a univariate analysis of variance. No significant intergroup differences were found regarding the test duration, total score, and average score of each question. The number of problems with perfect marks was higher in Group P than in Group C (P0.05), probably because Group P students could access the information of the previous question (s) within a problem. Thus, the differences of the examinees' performance between the two testing modes were small.

Even though English is most frequently the common language when the patient's native language differs from that of a dentist, the opportunities for Japanese undergraduate dental students to learn dental English are now quite limited. The purposes of our study were to investigate: the effectiveness and feasibility of the computer-assisted simulation materials as one solution strategy for dental English education in Japan, and the needs and demands for dental English from the learners' side. Interactive simulation materials for medical interviews in English and clinical cases which were translated to English, were delivered via Learning Management System (LMS) to nineteen trainee residents of dentistry (residents). Evaluation for the materials, learners' knowledge and interests in the contents, and ease of operation were obtained by post-questionnaire (response rates were 100% and 95%, respectively). Both questionnaire-surveys received positive feedback toward the materials, yet 47% answered that they lacked the level of knowledge about contents of the medical interview in English. Results were sufficient to suggest that the residents would like to have the opportunity to study or practice medical interview in English, or English related to dentistry, and that the simulation materials could be one of the solution strategies for opportunity provision.

Periodontitis is a chronic inflammatory disease that induces the destruction of tooth-supporting tissues, followed by tooth loss. Although several approaches have been applied to periodontal regeneration, complete periodontal regeneration has not been accomplished. Tissue engineering using a combination of cells and scaffolds is considered to be a viable alternative strategy. We have shown that autologous transplantation of periodontal ligament-derived multipotent mesenchymal stromal cell (PDL-MSC) sheets regenerates periodontal tissue in canine models. However, the indications for autologous cell transplantation in clinical situations are limited. Therefore, this study evaluated the safety and efficacy of allogeneic transplantation of PDL-MSC sheets using a canine horizontal periodontal defect model. Canine PDL-MSCs were labeled with enhanced green fluorescent protein (EGFP) and were cultured on temperature-responsive dishes. Three-layered cell sheets were transplanted around denuded root surfaces either autologously or allogeneically. A mixture of β-tricalcium phosphate and collagen gel was placed on the bone defects. Eight weeks after transplantation, dogs were euthanized and subjected to microcomputed tomography and histological analyses. RNA and DNA were extracted from the paraffin sections to verify the presence of EGFP at the transplantation site. Inflammatory markers from peripheral blood sera were quantified using an enzyme-linked immunosorbent assay. Periodontal regeneration was observed in both the autologous and the allogeneic transplantation groups. The allogeneic transplantation group showed particularly significant regeneration of newly formed cementum, which is critical for the periodontal regeneration. Serum levels of inflammatory markers from peripheral blood sera showed little difference between the autologous and allogeneic groups. EGFP amplicons were detectable in the paraffin sections of the allogeneic group. These results suggest that allogeneic PDL-MSC sheets promoted periodontal tissue regeneration without side effects. Therefore, allogeneic transplantation of PDL-MSC sheets has a potential to become an alternative strategy for periodontal regeneration.

The aim of this study was to develop, implement, and evaluate an inter- and intraprofessional education program with a peer support joint practice in which dental hygiene students teach medical and dental students about oral health care for older people requiring long-term care. In 2015 at Tokyo Medical and Dental University, 22 dental hygiene students in their third year at the School of Oral Health Care Sciences (OH3), 110 students in their third year at the School of Medicine (M3), and 52 students in their third year at the School of Dentistry (D3) participated in this program. The OH3 students practiced with a whole-body-type simulator to learn oral health care for older people and then taught the methods to the M3 and D3 students according to their self-designed teaching plan. All M3 and D3 students experienced being both practitioner and patient. The number of respondents and response rates on the questionnaires after the training were 22 (100%), 102 (92.7%), and 52 (100%) for the OH3, M3, and D3 students, respectively. Self-assessment by the OH3 students indicated that they could supervise other students sufficiently (77-86%), and 91% of them found the preclinical practice with the simulator efficient for the peer support joint practice. Almost all the M3 and D3 students reported that they gained understanding of the methods (99%), significance (100%), and important points of oral health care for older people (97%) in addition to the jobs and roles of dental hygienists (93%) because of this program. The M3 students understood the methods and significance of oral health care more deeply than did the D3 students (p

Gate-first high-k/metal-gate n-MOSFETs with a deep subnanometer (sub-nm) equivalent oxide thickness (EOT) of 0.58 nm were successfully fabricated with Schottky source/drain contacts using a low-temperature process. The key to achieving such a thin EOT is the use of a low-temperature process for the NiSi Schottky source/drain formation. A sulfur implantation technique was used to overcome the Schottky barrier height between Si and NiSi, which is the main problem in NiSi Schottky source/drain fabrication. The advantage of Schottky source/drain MOSFETs over conventional source/drain MOSFETs was successfully demonstrated.

To cite this article: Int J Dent Hygiene10, 2012; 61–66 DOI: 10.1111/j.1601-5037.2011.00528.x Yoshida N, Aso T, Asaga T, Okawa Y, Sakamaki H, Masumoto T, Matsui, K, Kinoshita A. Introduction and evaluation of computer-assisted education in an undergraduate dental hygiene Abstract: Objective: This paper introduced newly developed computer-assisted learning materials and reports of a survey of junior college dental hygiene students who have used them. Methods: We authored new educational material to promote students’ basic dental hygiene practice skills using a simulation software generator. A set of five developed materials were tested by 43 female second-year dental hygiene students during the second semester at a college in Chiba, Japan. The evaluation was conducted in the form of a questionnaire including open-ended questions. Students’ opinions were analysed using characteristic diagrams, a troubleshooting tool that can be used to visually illustrate the causes and effects of a problem. Result: The overall results of the evaluation were positive. The students were given five sets of simulation learning materials (SLMs). Eighty-three percent of the students felt that they could carry out independent study of clinical practice better after the virtual practice. Ninety-three percent of them felt that the exercises should be continued in the future, and eighty-eight percent of them felt that this virtual practice deepened their interest in other classes and training sessions. All of the students found the virtual practice beneficial for their learning. Discussion: The present results suggest that the students became conscious of their lack of knowledge through SLMs. These findings indicate that SLMs for practicing basic clinical procedures is beneficial.

The effects of the composition of La–Al–O gate dielectrics on metal–oxide–semiconductor field-effect transistor (MOSFET) characteristics and reliability properties were investigated in detail. It was found that the interface trap density (Dit) was greater for [Al]-enriched La–Al–O than for [La]-enriched La–Al–O. As a result, the drive current and the time-to-breakdown (Tbd) for the gate oxide were lower for [Al]-enriched La–Al–O than for [La]-enriched La–Al–O. It is thought that the large tensile strain at the interface with the Si substrate is responsible for the smaller Dit in the case of [La]-enriched La–Al–O.

Mobility (mob) and Lg dependence of high-field velocity (v) is systematically investigated. A wide variety of mob characteristics is realized with various gate dielectrics of SiO2, SiON, HfLaSiON, and HfLaAlSiON. At Lg=30nm, the sensitivities of v to mob and scaling in Lg, (dv/v)/(dmob/mob) and (dv/v)/(dLg/Lg), are 0.43 and -0.45, respectively: in quasi-ballistic transport regime, mob and scaling in Lg still play an important role on Ion improvement with v enhancement. High-k MISFETs do not show any particular v degradation in high-energy carrier transport. Mob-Tinv characteristics required for sub-22nm-node high-k gate-stacks are discussed based on the experimental data for mob and Lg dependence of v.

Alveolar ridge augmentation is an important procedure to restore tooth loss. Several types of graft materials have been used for augmenting the alveolar ridge. An injectable calcium phosphate cement (CPC) has been applied to periodontal bone defects and has shown favourable results. Thus, this CPC may work as an effective graft material for alveolar ridge augmentation. The aim of this study was to evaluate the effectiveness of the CPC for large-scaled (about 7 x 8 x 6 mm) ridge augmentation in dogs. Alveolar ridge defects were created bilaterally in the maxilla of six beagle dogs. The CPC was applied to one of the bilateral maxillary defects. The untreated defect on the contralateral side served as control. The animals were sacrificed at 6 months after surgery and decalcified histological specimens of the alveolar ridge were prepared histometrically and evaluated under a light microscope. Newly formed and reconstructed alveolar ridges covering the CPC were observed in all experimental sites. In the control sites, only slight newly bone formation was observed. Histomorphometrical analysis indicated that the CPC grafted group exhibited significantly (P = 0.0001) increased area and height in new bone formation compared with those of the control group. The results indicate that the CPC appears to be an effective material for alveolar ridge augmentation and may act as a space maintainer to conduct new bone formation.

歯科の専門家としての歯科衛生士が, さまざまな臨床の現場において具体的にどのような業務を担っているのかは把握されていない。本研究は, 歯周基本治療に関して歯科医師および歯科衛生士の連携の実態を知ることを通じて, 今後の歯科衛生士業務の発展に寄与することを目的とする。さらには, これからの歯科医療を担う学生教育の充実, チーム医療の発展を考えるうえでの基礎資料を得ることを期待する。調査は, 日本歯周病学会専門医が勤務している一般開業歯科医院の院長を対象として, 質問紙調査法により行った。質問項目は「歯周病の診断と治療の指針」を参考に, 主として歯周基本治療の段階での歯科衛生士の介入について質問する内容とした。合計202件の回答を得た結果, 院長経験年数と歯科衛生士が主として処置をおこなうユニット台数に有意な正の相関があった。また, 歯科衛生士が主として処置をおこなうユニット台数とは, 一日平均歯周炎病名患者数ならびに歯科衛生士が接する時間比率, 歯周基本治療の各段階など, 多数の項目と有意な正の相関が認められた。本調査により, 近年の歯科衛生士像, 歯科衛生士の臨床能力の高さ, および歯科衛生士の具体的業務内容の決定に関連する因子等が明らかになった。これらの結果より, 歯科衛生士教育への提案, および歯科衛生士の職域拡大の可能性について考察した。日本歯周病学会会誌(日歯周誌)51(3) : 238-251, 2009

Recombinant human bone morphogenetic protein-2 has been shown to promote bone formation because of its osteoinductive property. The purpose of this study was to evaluate the efficacy of rhBMP-2 delivered on a poly (D, L-lactic-co-glycolic acid) copolymer/gelatin sponge (PGS) in vertical alveolar ridge augmentation on height-reduced edentulous mandible to verify the retention of rhBMP-2 withstanding the pressure of soft tissues. Coronal defects of the alveolar bone were created in six adult beagle dogs. After a healing period of 9 weeks, PGSs with or without rhBMP-2 (0 or 0.4 mg mL(-1)) were implanted on the defects(6 mm in height, 30 mm in length, 8 mm in width). Sixteen weeks after implantation, the bone mineral content (BMC) and the total bone area were measured by peripheral quantitative computed tomography. The BMC and the total bone area of the defect sites with rhBMP-2 group were significantly greater (133+/-33 mg mm(-1), 277+/-54 mm2, respectively) than those of the control group (80+/-19 mg mm(-1), 155+/-49 mm2, respectively) (P

Factors that underlie the performance improvement of dopant-segregated Schottky (DSS) metal–oxide–semicondutor field-effect transistors (MOSFETs) compared with conventional (Conv.) MOSFETs are examined experimentally. Three factors are compared for DSS and Conv. MOSFETs; namely, effective junction depth, the hot carrier effect, and parasitic resistance. We found that all the following factors are associated with performance improvement in DSS MOSFETs: shallower junction depth, higher impact ionization rate, and lower parasitic resistance. It is considered that the shallower junction depth and lower parasitic resistance respectively contribute to the better short-channel-effect immunity and higher drive current of the DSS MOSFETs. The higher impact ionization rate is consistent with the higher carrier injection velocity, which is another factor of the drive current enhancement. We focus on the reduction of parasitic resistance and compare the components of the parasitic resistances of DSS and Conv. MOSFETs to analyze the factors of the reduction of parasitic resistance. We also speculate on the effectiveness of the parasitic resistance reduction in DSS FETs as high-performance devices for future LSIs.

Capacitance-voltage (C-V) characteristics of double-gate ultrathin silicon-on-insulator (SOI) MOSFETs are numerically investigated in detail. The measured back-gate bias dependence is reproduced by the Poisson-Schrodinger solver including the highly precise physical models for many-body interactions of carrier-carrier and carrier-ion, and for incomplete ionization of doping impurities in whole semiconductor regions of n+poly-Si/oxide/SOI/oxide/p-Si capacitor including the volume inversion. In addition, we study the higher subband effect at higher temperature in detail, in order to deduce the impacts of self-heating and nonstatic transport

Background and Objective Fibroblast growth factor-2 (FGF-2) regulates the proliferation and differentiation of osteogenic cells, resulting in the promotion of bone formation. Biodegradable gelatin sponges incorporating β-tricalcium phosphate (β-TCP) have been reported as a scaffold, which has the ability to control growth factor release, offering sufficient mechanical strength and efficient migration of mesenchymal cells. In this study, we evaluated the effects of the combined use of recombinant human FGF-2 (rhFGF-2) and gelatin/β-TCP sponge on ridge augmentation in dogs. Material and Methods Six male beagle dogs were used in this study. Twelve wk after tooth extraction, bilateral 10 × 5 mm (width × depth) saddle-type defects were created 3 mm apart from the mesial side of the maxillary canine. At the experimental sites, the defects were filled with gelatin/β-TCP sponge infiltrated with 0.3% rhFGF-2, whereas gelatin/β-TCP sponge infiltrated with saline was applied to the control sites. Eight wk after surgery, qualitative and quantitative analyses were performed. Results There were no signs of clinical inflammation at 8 wk after surgery. Histometric measurements revealed that new bone height at the experimental sites (2.98 ± 0.65 mm) was significantly greater than that at the control sites (1.56 ± 0.66 mm; p = 0.004). The total tissue height was greater at the experimental sites (6.62 ± 0.66 mm) than that at the control sites (5.95 ± 0.74 mm), although there was no statistical significant difference (p = 0.051). Cast model measurements revealed that the residual defect height at the experimental sites (2.31 ± 0.50 mm) was significantly smaller than that at the control sites (3.51 ± 0.78 mm; p = 0.012). Conclusion The combined use of rhFGF-2 and gelatin/β-TCP sponge promotes ridge augmentation in canine saddle-type bone defects.

Fully Ni-germanosilicided [Ni(SiGe)] gate electrode was systematically investigated by means of both structural analyses and electrical measurements. The authors fabricated Ni(SiGe)-gated MOS capacitors with various Ge fractions through the solid-phase reaction at Ni/polycrystalline SiGe (poly-SiGe) interface. It was found that Ge atoms can only be dissolved in NiSi phase, and then Ni(SiGe) phase is formed. In addition, even in the case that the thickness ratio of Ni to Si is equivalent to that required to form Ni2Si, Ge atoms induce phase change from Ni2Si to Ni(SiGe) near SiO2 interface. This phenomenon promotes condensation of Ge atoms in Ni(SiGe). The values of effective work function (Phieff) are independent of the Ge fraction in the low Ge fraction (Ge < 60%) Ni(SiGe) gate. On the contrary, the Phieff values begin to change to values larger than that of NiSi in the case of a Ge fraction higher than 60%. In addition, the Ge incorporation modulates the Phi eff shift effect of piled-up B atoms to the opposite direction compared to the NiSi cases reported previously. As a result, the controllable Phieff range for piled-up B atoms can be expanded to 0.47 eV near the Si midgap

An earlier study showed that an injectable calcium phosphate cement (CPC) served as a stable scaffold for bone formation and promoted histocompatible healing of periodontal tissue in dogs. In this study, we evaluated the influence of CPC on regeneration of periodontal defects with experimental periodontitis in dogs.Experimental periodontitis was induced by placing stainless-steel mesh on the mesial side of maxillary canines in six adult, healthy beagle dogs. Subsequently, intrabony defects were resized so as to be standard, and CPC was injected in the experimental bone defects. Non-grafted defects on the contralateral side served as controls. Twelve weeks after surgery, the animals were sacrificed and histologic specimens were prepared. Periodontal tissue healing was evaluated histologically and histometrically.Healing of periodontal tissues, in terms of bone and cementum formation, was consistently observed in the CPC-applied sites. CPC was partly replaced by new bone. New cementum and periodontal ligament-like tissue were observed between CPC and the root surface. New bone (P0.05), new cementum (P0.01), and new connective tissue attachment and adhesion (P0.05) were significantly enhanced in the experimental sites.Calcium phosphate cement provides stable wound healing and enhanced periodontal regeneration in periodontal defects in dogs with experimental periodontitis.

Background: Recombinant human bone morphogenetic protein-2 (rhBMP-2) has been shown to induce clinically relevant bone formation for orthopedic, craniofacial, and oral indications. It appears critical, in particular for onlay indications, that the associated carrier technology exhibits structural integrity to offset compressive forces in support of rhBMP-2-induced bone formation. The objective of this study was to evaluate a calcium phosphate (CP) cement, Ceredex™, as a candidate carrier for rhBMP-2 in a defect model with limited osteogenic potential. Materials: Bilateral, critical size, 6-mm, supra-alveolar, periodontal defects were created in six, adult, male, Hound Labrador mongrels. Three animals received rhBMP-2/Ceredex™ (rhBMP-2 at 0.20 and 0.40 mg/ml) in contralateral defect sites (implant volume/defect ∼1 ml). One defect site in each of the three remaining animals received Ceredex™ without rhBMP-2 (control). The animals were euthanized at 12 weeks postsurgery for histologic and histometric analysis. Results: Mean induced bone height exceeded 80% of the defect height for supra-alveolar periodontal defects receiving rhBMP-2/Ceredex™ without major differences between rhBMP-2 concentrations compared with approximately 40% for the control. The newly formed bone, a mixture of lamellar and woven bone in fibrovascular tissue, circumscribed relatively large portions of the residual Ceredex™ biomaterial. Inflammatory lesions were associated with limited bone formation in some sites. From a periodontal perspective, sites receiving rhBMP-2/Ceredex™ exhibited increased cementum formation compared with control, but without a functionally oriented periodontal ligament, and increased ankylosis and root resorption. Control sites exhibited early wound failure and exposure, loss of the Ceredex™ biomaterial, and limited bone formation. Conclusions: The Ceredex™ CP cement appears a potentially promising carrier technology for rhBMP-2 onlay indications. However, a slow resorption rate may prevent its wider use. This study does not support use of the rhBMP-2/Ceredex™ combination for periodontal indications.

Objectives: Subcutaneous and intramuscular implants of bone morphogenetic protein-12 (BMP-12) have been shown to induce formation of tendon and ligament tissue. BMP-12 induced a new attachment with a distinct fibrocartilaginous zone at the tendon-bone interface in the rat tendon-bone attachment model. Surgical controls showed poor healing and failure to reform the appropriate tendon–bone attachment morphologically. Application of recombinant human BMP-12 (rhBMP-12) to periodontal defects suggests that rhBMP-12 has the potential to support regeneration of the periodontal ligament (PDL). The objective of this pilot study was to evaluate this effect of rhBMP-12 in a tooth replantation model. Methods: Six, young adult, male Hound Labrador mongrel dogs were used. Maxillary and/or mandibular incisor and premolar teeth were extracted and the PDL was either left “intact” or removed by root planing. rhBMP-12 (1.0 mg/ml) or a buffer control was topically applied to teeth with “intact” PDL in contralateral jaw quadrants in each of 3 animals. The teeth were immersed in 1.0 ml of the rhBMP-12 or the buffer solution for 10 min and then replanted. The remaining three animals received rhBMP-12 (1.0 mg/ml) and the buffer control in a similar fashion applied to teeth instrumented to remove the PDL and cementum, and surface demineralized with citric acid. The animals were euthanized at 8 weeks postsurgery and block sections were collected and processed for histopathologic analysis. Results: No dramatic differences were found between teeth receiving topical rhBMP-12 and the buffer control. Application of rhBMP-12 did not have an apparent effect on new cementum and PDL formation in the tooth replantation model. Moreover, application of rhBMP-12 did not increase nor did it decrease the apparent presence and extent of ankylosis along the root surface compared to the control. Conclusions: The observations from this study do not support the use of topical rhBMP-12 to support the reestablishment of the PDL including regeneration of cementum and functionally oriented fibers, and to prevent ankylosis and root resorption following replantation of teeth.

Alveolar ridge aberrations commonly compromise optimal dental implant installation. To offset any variance between an aberrant alveolar ridge and prosthetic designs, bone augmentation procedures become necessary. The objective of this study was to evaluate bone formation and osseointegration at alveolar dehiscence defects following augmentation of the defect site with recombinant human bone morphogenetic protein-2 (rhBMP-2) in an absorbable collagen sponge carrier (ACS) at dental implant installation including transmucosal positioning of the dental implant.Four adult male Cynomolgus monkeys received dental implants in contralateral extraction socket sites with surgically created 6 x 4 mm buccal dehiscence defects following elevation of mucoperiosteal flaps. Contralateral sites received rhBMP-2/ACS (rhBMP-2 at 1.5 mg/ml; 0.1 mg/defect) or served as sham-surgery controls. The flaps were adapted and sutured around the healing abutments leaving the implants in a transmucosal position. The animals were sacrificed at 16 weeks postsurgery and block sections of the implant sites were harvested and prepared for histometric analysis.One dental implant from each treatment group failed to osseointegrate. Another 3 dental implants (sham-surgery controls) failed to osseointegrate with newly-formed bone in the defect area. Thus, 7 of 8 defect sites (4/4 animals) receiving rhBMP-2/ACS compared to 4 of 8 sites (2/4 animals) receiving sham-surgery exhibited evidence of osseointegration with newly formed bone in the defect area. Mean +/- SD defect height amounted to 5.3 +/- 0.2 and 5.4 +/- 0.1 mm for the rhBMP-2/ACS and sham-surgery sites, respectively. Vertical bone gain in rhBMP-2/ACS treated defects (3.9 +/- 0.3 mm) did not differ significantly from that in the sham-surgery control (3.7 +/- 0.4 mm; P0.05; paired t-test, N = 4). There were also no significant differences noted for coronal bone-implant contact (3.0 +/- 0.6 versus 3.6 +/- 0.5 mm), and bone-implant contact within the defect site (28.5% +/- 15.1% versus 27.4% +/- 31.7%) and within resident bone (46.9% +/- 26.8% versus 47.8% +/- 39.4%) for the rhBMP-2/ACS and control sites, respectively.The observations in this study point to a substantial native osteogenic potential of the alveolar process that has previously not been explored and show that surgical reentry observations of new bone formation may not necessarily indicate that osseointegration has occurred. Bone formation in control defects was substantially greater than predicted, limiting the value of adding an osteoinductive biologic construct.

In order to control the shape of the crystal–melt (C–M) interface, InSb crystal growth experiments using the horizontal Bridgman method have been carried out to clarify the effects of temperature gradient, cooling rate, and Sb composition of the initial melt. The shape of the C–M interface was almost flat at the initial stage of crystal growth. With progressing growth, the degree of distortion of the C–M interface shape, “concavity”, increased and reached a constant value. In the case of a uniform concentration distribution in the melt, the terminal concavity decreased with the decrease of temperature gradient. The terminal concavity decreased with the increase of cooling rate, but it saturated at a high cooling rate. Solutal Marangoni convection was intentionally induced by changing the initial Sb composition. The concavity could be controlled via solutal Marangoni convection without the change of temperature gradient or cooling rate. A flat interface was obtained when the solutal Marangoni convection decelerated the thermal Marangoni convection.

A novel injectable, fast setting calcium phosphate cement (CPC) is currently used in orthopedic therapy for bone fractures. This study evaluated the possibility of applying this cement to healing periodontal defects.Fenestrations and 3-walled periodontal defects were surgically created on bilateral first molars and canines in 5 beagle dogs. CPC was applied to the defects on one side of the mandible. Untreated defects on the contralateral side served as controls. CPC was applied to all defects in the maxilla. Twelve weeks after surgery, the animals were sacrificed and decalcified and undecalcified specimens were prepared. Periodontal tissue healing was evaluated histologically and histometrically under a light microscope.Healing of periodontal tissues in terms of bone and cementum formation was consistently observed in the CPC-applied sites. CPC was partly replaced by new bone. The residual CPC appeared detached from the denuded root surface. New cementum and periodontal ligament-like tissue were observed between the detached CPC and root surface. No unfavorable reaction was noted in the CPC-applied sites. No statistically significant difference was noted in the experimental or control sites under histometric analysis.Although there were no statistically significant differences between the 2 treatment groups, histological observation indicated that CPC seemed to act as a scaffold for bone formation and provided histocompatible healing of periodontal tissues in this study. This cement might be applicable to periodontal therapy; however, further investigations are required.

We demonstrated room temperature (RT) intense ultraviolet (UV) emission with wavelength in the range of 300-340 nm from In x Al y Ga 1-x-y N quaternary alloys grown by metal organic vapor phase epitaxy (MOVPE). We found that the UV emission is considerably enhanced by In segregation upon introducing approximately 5% of In into AIGaN. We fabricated multi-quantum wells (MQWs) consisting of In x1 Al y1 Ga 1-x1-y1 N wells and In x2 Al y2 Ga 1-x2-y2 N barriers. The intensity of the 320 nm band emission from the InAlGaN-based MQWs was as strong as that of the 410 nm band emission from InGaN-based QWs at RT. We also fabricated an InAlGaN/InAlGaN single (S)QW and clearly observed In segregation of submicron size from cathodoluminescence (CL) images. The temperature dependence of photoluminescence (PL) emission for InAIGaN-based QWs was greatly improved in comparison with that of GaN- or AlGaN-based QWs. We also achieved a hole concentration of 3 × 10 17 cm -3 for large bandgap (around 4eV) quaternary In x Al y Ga 1-x-y N by Hall measurements. Finally, we fabricated UV light-emitting diodes (LEDs) using InAIGaN active region and achieved efficient 345 nm emission.

We demonstrate 230 to 250 nm efficient ultraviolet (UV) photoluminescence (PL) from AlN(AlGaN)/AlGaN multi-quantum-wells (MQWs) fabricated by metal-organic vapor-phase-epitaxy (MOVPE). Firstly, we show the PL spectra of AlxGa1—xN on SiC over the whole compositional range, i.e. from GaN to AlN, emitting from near band-edge. We observed a drastic intensity enhancement of PL emission by small incorporation of GaN into AlN. We systematically investigated the PL properties of AlGaN MQWs consisting of wide bandgap AlGaN (Al content: 53 to 100%) barriers. We obtained efficient PL emission of 234 and 245 nm from AlN/Al0.18Ga0.82N and Al0.8Ga0.2N/Al0.18Ga0.82 MQWs, respectively, at 77 K. The emission from the AlGaN MQWs were several ten times stronger than that of bulk AlGaN. We found that the PL from AlGaN MQW is as efficient as that of InGaN QWs at 77 K.