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Volume 66 (1999)
- Issue 4 Pages 311-
- Issue 3 Pages 235-
- Issue 2 Pages 165-
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Volume 66, Issue 4
Displaying 1-15 of 15 articles from this issue
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Yoshio Nakamura1999 Volume 66 Issue 4 Pages 311-320
Published: December 30, 1999
Released on J-STAGE: October 08, 2010
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—Viewing Primate Tool-Use as an Evolutionary Precursor of the Language—Atsushi Iriki1999 Volume 66 Issue 4 Pages 321-330
Published: December 30, 1999
Released on J-STAGE: October 08, 2010
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Nobuyuki Kawashima, Shigezo Hirano, Makoto Morigami, Yoshiko Yamaguchi ...1999 Volume 66 Issue 4 Pages 331-338
Published: December 30, 1999
Released on J-STAGE: October 08, 2010
JOURNAL FREE ACCESSOkinawa Prefecture has been promoting dental treatment and oral health care in places where there are no dentists. The Ministry of Health and Welfare has been cooperating with eight dental colleges, including Tokyo Medical and Dental University, for promotion thereof since 1961. The 155th promotion was held on Tokashiki Island.
The caries prevalence rate of the students on Tokashiki Island was relatively high compared with the average caries prevalence rate of the same age group throughout Japan, and most of the caries were thought to be due to too many soft drinks. Resin filling was the most popular treatment during this promotion. Severe periodontal disease was observed in middle-aged persons, but we could only perform initial periodontal treatment because of the limited treatment period. Complete or partial dentures were made or repaired for many elderly. The questionnaire study showed most of the denture wearers on Tokashiki Island were satisfied with their dentures, although many dentures did not fit, and the prescription was improved.
The period of this promotion was too short to perform complete dental treatment and to prevent caries and periodontal disease, and primary prevention and higher dental hygiene education should be strengthened in no dentist areas like Tokashiki Island.View full abstractDownload PDF (2724K) -
Mariko Nagase1999 Volume 66 Issue 4 Pages 339-350
Published: December 30, 1999
Released on J-STAGE: October 08, 2010
JOURNAL FREE ACCESSIn this study, the treatment results of apicoectomy with orthograde filling were compared with those of apicoectomy with retrograde gutta-percha filling and retrograde sponge gold filling. The long-term followup results of the teeth treated by apicoectomy are presented, and the possible prognostic factors are discussed. The healing process of the apical bone cavity was analized with standard X-ray techniques and image analysis system.
One hundred nineteen teeth were apicoectomized with orthograde filling, 196 teeth with retrograde gutta-percha root filling and 42 teeth with sponge gold filling.
There was no significant correlation between the treatment results and the sex or age of the patients, kinds of teeth, preoperative radiolucent areas, the number of operations or histopathological diagnosis of apical lesion. The success rate of apicoectomy with orthograde filling or apicoectomy with retrograde guttapercha root filling was significantly higher than that with retrograde sponge gold filling. The filling materials and the operation method were considered to be the most important factors for a successful outcome.
Bone reconstruction was found to start from the periphery of the bone cavity and the bone defect became gradually reduced in a star-like patten. At 4 months after operation, in the successful cases, the area of bone cavity decreased 46-64% compared with before operation, but in the unsuccessful cases, the area did not change or increased 75-120%. Thus at 4 months after operation, it is possible to determine whether or not apicoectomy is successful.View full abstractDownload PDF (7396K) -
—Part. I: Observation of Mastication Using Inter-jaw Positional EMG—Yoshihiro Tanaka1999 Volume 66 Issue 4 Pages 351-360
Published: December 30, 1999
Released on J-STAGE: October 08, 2010
JOURNAL FREE ACCESSWhen masticatory efficiency is measured in the normal manner, it is necessary to collect samples. The purpose of this study was to devise a possible method of measuring masticatory efficiency, obviating the necessity for collection of the sample. Peanuts mastication by subjects whose degree of comminution was already known was observed by using an“Inter-jaw positional EMG”in which an element of the jaw positions is combined with EMG. Observation of the Inter-jaw positional EMG enables understanding the appearances of each 1-cycle chewing comminution. Moreover, changes in muscle activity and jaw movement caused by the progress of mastication can be observed by arranging the Inter-jaw positional EMG to record the chewing cycle, several times. In addition, three phases in peanut mastication was observed, and it was found that analysis of the first two phases when the changes appear is very effective because the changes move similarly with the changes of particle size. In addition, the Inter-jaw positional EMG and distribution of particle size were analyzed, and both changes caused by the progress of the cycle were similar. Thus, it is possible to estimate of the masticatory efficiency using the Inter-jaw positional EMG.View full abstractDownload PDF (1338K) -
Junichi Furuya1999 Volume 66 Issue 4 Pages 361-369
Published: December 30, 1999
Released on J-STAGE: October 08, 2010
JOURNAL FREE ACCESSThe purpose of this study was to evaluate effects of wearing complete dentures on swallowing in the elderly. Sixteen nondysphagic edentulous volunteers (mean age: 75.0yrs) were studied in terms of surface electromyography of the anterior belly of digastrics and masseter muscles, tongue pressure toward the hard palate, and the laryngeal movement. The subjects swallowed 2ml water under four conditions, with upper and lower dentures, without lower denture, without upper denture, and without upper and lower dentures. Dipper-type of swallowing was prescribed. A repeated-measures ANOVA was used for statistical analysis. Total swallowing duration and the latent period until laryngeal elevation were significantly prolonged without upper or lower denture, and without both dentures (p<0.05) . They were significantly shorter without lower denture than those without upper denture, and without both dentures (p<0.05) . Duration of the preparatory stage was significantly prolonged without upper denture, and without both dentures comparing with the others (p<0.05) . Duration of the oral stage was significantly prolonged without upper denture, and without both dentures comparing with the duration with both dentures (p<0.05) . There were no changes in the pharyngeal stage with or without dentures. The prolongation of total swallowing duration was due to the prolongation of the preparatory and oral stages. The prolongation of swallowing would affect the oral pharyngeal coordination of swallowing, and exacerbate the depression of swallowing functions with aging. These results suggested that wearing complete dentures contributes to maintain physiological procedure of swallowing in the elderly.View full abstractDownload PDF (3670K) -
Kenichi Kasahara1999 Volume 66 Issue 4 Pages 370-381
Published: December 30, 1999
Released on J-STAGE: October 08, 2010
JOURNAL FREE ACCESSPrevious studies have shown that molar teeth pulsate at rest and displace linguo-apically during clenching at the intercuspal position. These results suggested that teeth do not contact adjacent teeth and the distance between all adjacent teeth decreases during clenching. This study was conducted to investigate the interproximal contact relationship during clenching by a CCD microscope.
Two subjects (Males: Aged 28 years) with normal dentition and occlusion were selected forin vivoobservation. The observed contact points had optimum tightness which was defined by the insertion of a 50 μm thick stainless steel strip with some resistance, but not by that of a 110 μm strip. A space existed between the teeth at rest and the CCD microscope positioned on the buccal side could detect light from the lingual side. For dynamic observation, a lingual plate with a light source was fitted to each subject. When the subjects clenched, the light band was divided. Furthermore, a digital tension gauge was used to measure the interproximal force for pulling thin Titanium strips. The interproximal force significantly increased during clenching.In vitro, to estimate the relation between the width of the light band and the Interproximal distance, two extracted teeth were used. Light bands were analyzed by computer.
The distance between adjacent teeth at rest was 3-21μm, and interproximal spaces disappeared during clenching. These results suggested that teeth do not contact adjacent teeth at rest but they do during clenching.View full abstractDownload PDF (14794K) -
Minoru Kimura1999 Volume 66 Issue 4 Pages 382-396
Published: December 30, 1999
Released on J-STAGE: October 08, 2010
JOURNAL FREE ACCESSThe purpose of this study was to elucidate optimal relations between functional load distribution of periodontal supports and mucosal supports from denture bearing area in maxillary bilateral free-end-saddle RPD. Therefore, specially designed, palatal plate changeable RPDs were designed without changing occlusal relation and all other elements. The denture bearing area were measured by the thin foil method, standardized by Cubscraniophor. After wearing RPD, clinically physiological observation in occlusal contacts and loads were carried out by Prescale with an exclusive computer analyzing system. Masticatory muscular EMG and occlusal contacts were recorded with Prescale at IP clenching. Five maxillary bilateral shortened archcases were used for this prosthodontic research and studied in periodically at pre- and post-RPD treatments. These data were analyzed and compared with those of the control group. The outlines of these results were as follows:
1. The relation with mucosal denture supporting area and musculature activities were shown as y= -0.19x2+5.3x+93.8, the maximal value: 13.48 cm2.
2. The direct proportion was observed in relation with anteroposterial location of masticatory center in dental arch and denture bearing area.
3. The optimal denture bearing area was observed in each shortened arch case.View full abstractDownload PDF (6101K) -
—Analysis in an in vitro Brainstem-Spinal Cord Preparation from Newborn Rats—Tomotada Hokazono1999 Volume 66 Issue 4 Pages 397-405
Published: December 30, 1999
Released on J-STAGE: October 08, 2010
JOURNAL FREE ACCESSWhether reflex responses of the trigeminal motoneurons induced by the stimulation of the trigeminal sensory root (Vs) are inhibited by heterotopic noxious conditioning stimulation applied to the tail was investigated, using a novelin vitrobrainstem-spinal cord preparation isolated together with the hindlimbs and tail of newborn rats. The neural activity evoked by electrical stimulation of Vs with a suction electrode was monitored from the trigeminal motor root (Vm) with a suction electrode in a recording chamber. The tail was pinched with forceps as the heterotopic noxious conditioning stimulation (tail pinch) . In some experiments, a plastic septum sealed with Vaseline was used to partition the pool for the brainstem from that for the other part of the preparation. The results were as follows: (1) electrical stimulation of Vs induced a long lasting (duration: over 300 ms) positive potential with a peak-latency of about 80 ms in Vm; (2) the response was suppressed in amplitude by the tail pinch; (3) the suppressive effect of the tail pinch was blocked by bath application of naloxone (50pM) to the brainstem chamber; and (4) removal of the mesencephalon from the preparation did not affect the suppressive effects of the tail pinch. It was concluded that the trigeminal reflex response is suppressed by noxious conditioning stimulation on the remote region, and that in this suppression opioid receptors located in the lower brainstem are involved. This in vitro preparation will be useful for investigations of the neural mechanisms underlying nociceptive modification of neural activity.View full abstractDownload PDF (8352K) -
Akiyoshi Shinya, Yoshimi Ooe, Hiroaki Komatsu, Mari Yamada, Takayuki N ...1999 Volume 66 Issue 4 Pages 406-412
Published: December 30, 1999
Released on J-STAGE: October 08, 2010
JOURNAL FREE ACCESSThe purpose of this study was to investigate the effect of firing conditions on color stability.
Three commercially available porcelains for high functional gold alloys, Carrara (CA), Deguceram Gold (DE) and Duceragold (DU) were used. In this study color stability was investigated under fire treatment of 1st, 3rd, 5th times and firing temperatures of 0, 20, and 40°C higher than the manufactures standard temperature (CA: 845°C, DE: 780°C, DU: 780°C) . L was degreased in CA 5 times, DE 3 times, DU by repeated firing. No difference was observed among L of firing temperatures DE and DU, but L was degreased in CA with firing temperatures of 40t higher. a was degreased in CA, DU, DE with repeated firing. a was degreased 5 times at firing temperatures of higher. b was degreased in DU, but b was increased in CA and DE with 5 firings. b was increased with 5 findings at firing temperatures of 40°C higher.View full abstractDownload PDF (846K) -
[in Japanese], [in Japanese], [in Japanese]1999 Volume 66 Issue 4 Pages 413
Published: December 30, 1999
Released on J-STAGE: October 08, 2010
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[in Japanese], [in Japanese], [in Japanese], [in Japanese]1999 Volume 66 Issue 4 Pages 414
Published: December 30, 1999
Released on J-STAGE: October 08, 2010
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[in Japanese], [in Japanese], [in Japanese], [in Japanese]1999 Volume 66 Issue 4 Pages 415
Published: December 30, 1999
Released on J-STAGE: October 08, 2010
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[in Japanese], [in Japanese], [in Japanese]1999 Volume 66 Issue 4 Pages 416
Published: December 30, 1999
Released on J-STAGE: October 08, 2010
JOURNAL FREE ACCESSDownload PDF (1782K) -
[in Japanese]1999 Volume 66 Issue 4 Pages 417
Published: December 30, 1999
Released on J-STAGE: October 08, 2010
JOURNAL FREE ACCESSDownload PDF (156K)
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