Masahiro Tanaka

Osaka Dental University, Ōsaka, Ōsaka, Japan

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Publications (13)1.25 Total impact

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    ABSTRACT: PURPOSE: The aim of this study is to examine the factors, which predict the effect of mandibular condylar movement exercise (MCME). MATERIAL AND METHODS: We investigated the efficiency of MCME and the significant difference in average age and the mean duration length of closed lock symptoms prior to the initial consultation in both success cases and failure cases in initial visiting. Seventy-four women aged between 19 and 75 (mean: 41.4) years were included in this study. RESULTS: On the initial visiting day, the success cases were 50 cases (67.6%) and the failures were 24 cases (23.4%). The average age of success cases is 38.0years, and failure cases are 48.4years. Duration of the lock in success cases is 35.3days, and failure cases are 87.6days. CONCLUSION: These results suggested that lower improvement rates thus correlated with increasing age with exercise. MCME is effective mouth-opening exercise in patients with a history of short duration of locking. In conclusion, age and duration of locking, it must become the important factor predict an effect MCME.
    Journal of cranio-maxillo-facial surgery: official publication of the European Association for Cranio-Maxillo-Facial Surgery 07/2012; · 1.25 Impact Factor
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    ABSTRACT: Recently, there has been considerable interest in finding novel applications and functions for existing dental materials. We found that, at room temperature and atmospheric pressure, titanium oxide spontaneously generates nanostructures very similar to the "nanotubes" created by TiO(2) sputtering. The aim of this study was to evaluate the ability of this surface to affect the cellular osteogenic differentiation response. Titanium disks without and with a 'nanosheet' deposited on their surface were used as the control and test groups, respectively. Cell culture experiments were performed with SD rat bone marrow cells, which were seeded into microplate wells and cultured in media designed to induce osteogenic differentiation. We measured alkaline phosphatase (ALP) activity, osteocalcin (OCN) production, calcium deposition and Runx2 gene expression to assess the levels of differentiation. After 14 and 21 days, cellular ALP activity was significantly higher in the test group than in the control group. After 28 days, cells in the test group also showed significantly more calcium deposition and OCN production than those in the control group. There was significantly different expression of Runx2 mRNA in the test group compared to the control group after 3 days of culture. In conclusion, these data suggest that titanium implants modified by the application of nanostructures promote osteogenic differentiation, and may improve the biointegration of these implants into the alveolar bone.
    Journal of prosthodontic research. 05/2012; 56(3):170-7.
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    Junko Tanaka, Norio Mukai, Muto Tanaka, Masahiro Tanaka
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    ABSTRACT: Objective. The purpose of this study was to investigate whether teeth that have undergone prosthetic restoration are under conditions that promote caries recurrence. Methods. The subjects were 20 dentate adults with both a healthy tooth and an affected tooth entirely covered with a complete cast crown in the molar regions of the same arch. The pH was measured in plaque adhering to the margin of the tooth covered with a complete cast crown and adhering to the cervicobuccal area of the natural tooth. In addition, the numbers of cariogenic bacteria (mutans streptococci and lactobacilli) were measured employing the saliva test. The relationships between the number of cariogenic bacteria and plaque pH of the natural tooth and between the number of cariogenic bacteria and plaque pH of the tooth covered with a complete cast crown were investigated. Results. The plaque pH of the tooth covered with a complete cast crown decreased as the numbers of SM and LB increased. The natural tooth were also influenced by the number of SM. Conclusion. Secondary caries are likely to develop from the marginal region of the crown in the oral cavity with a high caries risk unless a preventive program is prepared and the oral environment is improved following the program.
    International Journal of Dentistry 01/2012; 2012:452108.
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    ABSTRACT: It was proposed that technologies derived from CAD-CAM and computed tomography may be useful for flapless implant treatment procedures. The aims of this study were to validate the reliability of this concept in a prospective 12-month clinical study. Twelve patients with fully edentulous areas in their mandibles were included in this study. A total of 71 implants were inserted in interforaminal regions by use of a CAD/CAM drill template(), specially designed for flapless implant surgery. To assess the degree of pain and discomfort, the patients were examined at 2 days and 1 week after surgery. Patient satisfaction and implant functionality were further evaluated at follow-up intervals of 1, 3, 6, and 12 months postoperatively. One implant failed early in 1 patient. All of the other implants were in a good functional state throughout the study. The mean marginal bone loss after 1 year of follow-up was 0.3 mm (SD, 0.1) at center, 0.5 mm (SD, 0.1) at canine and 0.7 mm (SD, 0.2) at distal fixtures, respectively. Statistically, there was not significant differences among each sites(P>.05)The mean ISQ change after 1 year of follow-up was -1.05 (SD, 2.76) at center, -0.85 (SD, 2.59) at canine and -1.27 (SD, 2.18) at distal fixtures, respectively. This prospective pilot study showed that the use of CAD/CAM technology and flapless implant surgery may be considered reliable for fully edentulous mandible of patients.
    Journal of Dental Rehabilitation and Applied Science. 01/2011; 27(4).
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    Junko Tanaka, Masahiro Tanaka
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    ABSTRACT: The purpose of this study was to investigate the relationship between the number of missing teeth (MT) and the statuses of oral environmental factors (the stimulated salivary flow rate, buffering capacity, and the counts of mutans streptococci, lactobacilli, and Candida) in the elderly. The subjects were 64 elderly subjects with fixed prostheses and 49 who wore removable partial dentures aged over 65 years. We used one-way ANOVA to test for overall differences of the number of MT among 5 oral environmental factors. The significant differences were observed in the lactobacilli counts for different number of MT. The number of MT increased with an increase in the lactobacilli counts with removable denture. In conclusion, for the patients wearing removable dentures, increasing number of MT was associated with an increase in the lactobacilli counts in saliva. For the patients with crowns and fixed partial dentures, the number of MT was not significantly affected by salivary mutans streptococci, lactobacilli, and Candida counts.
    International Journal of Dentistry 01/2010; 2010.
  • Junko Tanaka, Masahiro Tanaka, Takayoshi Kawazoe
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    ABSTRACT: The purpose of this study was to investigate oral environmental risk factors involved in caries incidence in the elderly. We investigated the relationship between the oral environment factors of the elderly with both fixed prostheses and removable prostheses at baseline and at follow-up and examined time-course changes of each oral environmental factor by prosthesis type. The subject group consisted 11 elderly patients with fixed prostheses and 11 who wore removable prostheses. We examined oral environmental factors by saliva tests. Five oral environmental factors were examined: the stimulated salivary flow rate, buffering capacity, and the counts of mutans streptococci (SM), lactobacilli (LB), and Candida (CA). We compared these factors for subjects with fixed prostheses and those wearing removable prostheses at baseline and at follow-up. Furthermore, 3-year changes in the factors of each oral environment were compared and evaluated. Significant differences were observed between the two groups in the salivary microbial counts of SM and LB at baseline and at follow-up. The LB counts increased in the Denture group during the 3-year period and significant differences were noted. We found that fixed prostheses are less cariogenic, and removable prostheses cause an increase in the cariogenic bacterial count. Regarding time-course changes by the type of prosthesis, the LB count tended to increase in the subjects with removable prostheses. The risk of caries due to a fixed prosthesis may be lower than that of removable prostheses.
    Journal of prosthodontic research. 05/2009; 53(2):83-8.
  • Naoya Uemura, Masahiro Tanaka, Takayoshi Kawazoe
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    ABSTRACT: Neck pain is one of the main symptoms of temporomandibular disorder. Muscle activity of the sternocleidomastoid muscle during occlusion has been clarified in recent years. We reported that when healthy individuals were instructed to chew rapidly, the activity of the sternocleidomastoid muscle responded to activity of the masseter muscle, however, during voluntary jaw opening, activity of the sternocleidomastoid muscle did not respond, but worked actively due to motor programming. The objective of the present study was to investigate the learning effects of repetitive training, that is, changes in activity mode of the neuromuscular system. The sternocleidomastoid and the anterior belly of digastric muscles in 8 healthy male adults were analyzed. In response to acoustic stimulation, each subject was instructed to open their mouth as quickly and widely as possible a total of 30 times with a break between measurements. EMG-reaction times (RT) of the sternocleidomastoid and anterior belly of digastric muscles were measured, and the length of time from the start of EMG activity of agonist to the start of actual movement was measured. In all subjects, at first measurement, EMGRT of the sternocleidomastoid muscle did not precede that of the anterior belly of digastric muscle. With each measurement, the difference in EMG-RT between the sternocleidomastoid and the anterior belly of digastric muscles decreased, and in 6 of the 8 subjects, EMG-RT of the sternocleidomastoid muscle preceded that of the anterior belly of digastric muscle. Repetitive task movement alters the start times of muscular activities, and from the perspective of EMG kinesiology, motor learning effects were confirmed with maximum ballistic voluntary jaw opening.
    Nihon Hotetsu Shika Gakkai Zasshi 11/2008; 52(4):494-500.
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    ABSTRACT: We previously reported correlations between the pressure pain threshold (PPT) at the styloid process, which represents individual pain sensitivity, and PPTs of the masticatory muscles in healthy subjects, and proposed the 95% confidence interval (95%CI) of the PPT at the styloid process as a reference range. In this study, we evaluated its usefulness as a reference range. Serial changes in the PPT relative to the 95%CI were studied in 7 healthy subjects. Next, the determination of abnormal sites in the PPT relative to the 95%CI was studied in 7 patients with temporomandibular disorders (TMD). In the healthy subjects, the PPT remained within the 95%CI at all sites. Since the PPT deviated from the 95%CI at some sites in TMD patients, abnormal sites could be determined. The 95%CI of the PPT at the styloid process is useful as a means for the evaluation of muscle symptoms of TMD patients.
    Nihon Hotetsu Shika Gakkai Zasshi 08/2008; 52(3):381-7.
  • Prosthodontic Research & Practice 01/2007; 6(4):276-281.
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    ABSTRACT: Recently, there have been reports in favor of avoiding prosthodontic intervention as Shortened Dental Arch (SDA) in Northern Europe. However, many of these reports were conducted through interviews and questionnaires, and so the evaluation of the results lacked objectivity. Thus, this research analyzed the clinical status of SDA. For the selection of subjects, seven patients (average age: 59.3+/-13.2 years old) who had had the free-end missing on both sides of the lower dental arches for over five years were chosen as the SDA group. As the complete dental arch (CDA) group, seven patients (average age: 61.3+/-9.6 years old) who had no clinical defects in their masticatory function, and who had no missing teeth other than the third molar, were selected. Measurement items in this study were occlusal contact areas for the mandible premolar, center of force, occlusion time, and interdentium. The Mann-Whitney U test was used for statistical analysis and the significance level was assumed to be 5%. The results were as follows: 1) The occlusal contact area of the mandible premolar of SDA was significantly large. 2) The center of force of SDA was significantly forward. 3) The occlusion time of SDA had a tendency of prolongation. 4) Interdentium of 3 2 | 2 3, 4 3 | 3 4 and 5 4 | 4 5 of SDA were significantly wide. There were differences of clinical parameters between SDA and CDA in this study.
    Nihon Hotetsu Shika Gakkai Zasshi 02/2006; 50(1):26-34.
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    ABSTRACT: Oral care and oral treatment are promoted in health care service facilities. However, disorders of eating, mastication and swallowing and care management of meal were get behind. This study investigated them in health care service facilities. Doctors who work in facilities were screened for care management of meal using questionnaire. Inpatients were screened for age, meal menu, vertical stop, prosthetic treatment, satisfaction of mastication and difference of meal menu in the home and in the facility. Doctors and care workers have little understanding of mastication. Inpatients were satisfied to be able to eat rice in the home and in the facility. It is of paramount importance to have remaining teeth, to maintain vertical stop and to have prosthetic treatment. Education on the importance of mastication is needed. The research results show that new action and diagnosis method for deciding menus aiming at mastication of steamed rice need to be developed.
    Nihon Hotetsu Shika Gakkai Zasshi 07/2005; 49(3):469-77.
  • Prosthodontic Research & Practice 01/2005; 4(1):63-68.
  • Prosthodontic Research & Practice 01/2002; 1(1):24-30.