The various factors in relation to existence of fungi in denture plaque accumulated on the mucosal surface of denture plate were studied. Fungi were isolated from denture plaque of 57 patients (23 males and 34 females) and dental plaque of 50 students. Fungi were identified by means of minitek system (B.B.L.) and Candida check (latron). Isolation frequency of fungi was shown by percentage of patients which fungi isolated. The results were as follows:
1. Isolation frequency of fungi from denture plaque was 86% and much higher than that of dental plaque (18%).
2. Candida albicans was isolated from both plaque, but Candida tropicalis and Torulopsis glabrata were only detected in denture plaque.
3. The species and frequency of fungi isolated from denture plaque were increased with increase of wearing period or in case of denture with complicated design.
4. Not only coccoid and filamentous cells but fungusform cells were observed in denture plaque by scanning electron microscopy.

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The purpose of this study were estimated the clinical effects of complete dentures which were fitted five years ago. The subjects were 114 edentulous patients who were treated at the Tsurumi University Hospital from 1974 to 1976.
The questionaire regarding complete denture was sent out to the patients, and who were recalled to inspect their clinical conditions of oral tissues and dentures, closely.
We received answers of the questionaire from 79 persons. 60 persons of them answered that they could visit for personal interview and clinical examination. 54 persons had used the dentures continuously for five years but 25 persons did not use the dentures. 41 persons expressed satisfaction with mastication, 40 persons with the speaking ability and 38 persons with the appearance. 44 persons actually visited the Tsurumi University Hospital at recall. 44 subjects consisted of 24 males and 20 females. The range of the age distribution was from 40's to 90's years old.
The results of clinical examination were as follows.
1) Oral mucous membrane symptomes were found in 24 persons.
2) 41 upper complete dentures were judged good retention.
3) Denture plaque was seen in 34 subjects.

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116 Poly-Sulfone Dentures (PSDs) have been set to 86 patients over a period of one year from June 1981 ot May 1982. We obtained following results by surveying postoperative conditions of these PSDs.
1) We observed 27 PSD troubles which were set to 23 patients. Most of the troubles were breakage of denture base and displacement of artificial tooth.
2) We think that the main factors of PSD base breakage were due to its tendency to deflect for the PSD's small modulus of elasticity and the lack of resistance to fatigue.
3) We could think that the main factors of displacement of artificial tooth were due to no presence of adhesion between PS and artificial tooth, no full injection of PS into the retention holes and its nature of easy deflection.

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Pulsatile tooth oscillation has been noticed as an index to diagnose the condition of periodontal function because this is influenced by dynamical properties of periodontium.
Thereupon, this study was performed to analyze this phenomenon by recording in the labio-lingual direction with the optical fiber transducer and modeling of the stochastic process.
Clinically normal upper incisors were subjected in five males lying in supine. The followings were analyzed in the frequency domain, i. e. the day course change, the change within one day, the change under local infiltration anesthesia, and the difference between individuals.
And firstAnd first of all, the records were observed in the domain. Then the digitizations were carried out digital forms for signal time history records, and discrete values of them were qualified on stationarity, periodicity, and normality. Thereafter, these data were transformed into auto-power spectrum.
As the results, the following findings were obtained.
1. These time series data could be considered as the Gaussian stationary stochastic process within a range of finite time.
2. From the test for equivarence of power spectra,
a) All subjects had no significant difference between each record of running four days and after about one month.
same tooth showed no significant difference in any subject.
c) Five minutes after infiltration of Epinephrine (about 6μEg), high frequency component forming wave increased relatively, and three subjects had significant difference.
d) Visual inspection of each subject in the time domain showed that one subject who had evidently dissimilar pattern was significantly different from another four subjects. And one subject who had been undistinguishable inc inspection was significantly different from another four.subjects.

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A study was made of the behavior of postcores and tooth structures under various post lengths and post diameters with the strain gauge method and the finite element method.
Endodontically treated upper central incisors under various post lengths and post diameters of metal postcore were loaded with a horizontal 1kg weight at the lingual surface and strains at the cervical root surface were analyzed.
Two-dimentional finite element models of porcelain jacket crowns on the upper central incisor were developed. The finite element analysis 1 was carried out of 6 sizes of post length (5.0mm, 6.0mm, 7.0mm, 8.0mm, 9.0mm and 10.0mm) and 3 sizes of post diameter (1.0 mm, 2.0mm and 3.0mm).
For the purpose of making more clear as to mechanism of fracture of the post-core and the tooth struc ture, the finite element analysis 2 and 3 were carried out. The cervical cement layer (under the analysis 2) and the whole cement layer (under the analysis 3) between the post-core and the tooth structure were assumed to be elastic rubber materials to have the model behavior more emphatically.
The model was loaded with a statically concentrated horizontal 1kg weight at the linguo-incisal edge from the lingual side.
The results obtained as follows:
1. Under the results of the tooth model experiment, severe compressive stress generated at the labio-cervical root surface.
And stresses grew gradually higher in every part of the cervical root surface with decreased post length and increased post diameter.
2. Comparison among the finite element analysis 1, 2 and 3 suggested that stresses generated in the post-core and the tooth structure were increased, even if the rigidity of the abutment tooth was grown up according as post length and diameter were increased.

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Recently in dental treatment, various considerations apply the function of living tissue are exerted all possible efforts. Especially in prosthetic cases on remaining a few tooth without extraction, overdenture is reconsiderd new merits. It is supported that one of the advantage is the use of mechanoreceptor of periodontal ligament. Though, there is no reports that conclude it enough.
Accordingly, observing the effect of the mechanoreceptor of periodontal ligament on the masticatory function in full overdenture used “O'ring” stud attachments on bilateral mandibular canines, the author studies on the masticatory force under anesthesia with “semi-conductor”. As the results of these studies, the author arrived at the following conclusions.
1. The masticatory forces under anesthesia were larger than in normal, and there was a tendency that these increase from 1st masticatory period to 4th. The increasing rate was highest in the ham.
2. The rhythm of masticatory forces under anesthesia were slower than in normal, and there was a tendency that these increase from 1st masticatory period to 4th. And yet in the ham, such tendency weakened rapidly.
3. The integrated amounts of masticatory forces under anesthesia were smaller than in normal.
From these studies, it was given a suggestion that under anesthesia the full overdenture wearers masticated more strongly than in normal. Though, the duration was short and the integrated amounts of masticatory forces were little. So, under anesthesia the full overdenture wearers did not masticate efficiently and rhythmically. It is inferred that such reason is the lack of information from the mechanoreceptor of periodontal ligament under anesthesia. Therefore it was estimated the use of remaining the roots in full overdenture.

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