The alveolar bone of edentulous ridge is resorbed after the teeth extraction andthe subsequent denture insertion. For the periodontal structure, the stress transmitted along the longitudinal axis is favorable, but the horizontal stress is destructive. Under the overdenture application which the retained teeth have the reduced clinical crown, it is possible to prevent the alveolar bone resorption and to improve the involved teeth. However it is difficult for the inclined teeth to get the successful results.
In a case, having a few remained teeth contained the embedded root stump and the
overdenture being applicated, we obtained the suggestion as follows.
1. Also the embedded root stump is useful to prevent the alveolar bone resorption.
2. The top and direction of longitudinal axes of the inclined abutment teeth can be determined by means of surveying the least teeth movement when the stress was applied to the teeth by the fingers with dental pincette.
3. Also to the inclined abutment teeth, it is possible to transmitt the stress along the longitudinal axes, when the overdenture has the contact with the short dome coping at the top and in the inferior area to the longitudinal axes inclined, and is relieved in the superior area to its axes.

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TMJ noise is one of the main symptom of TMJ disfunction. In this study the opening and closing movement of the mouth in subjects conscious of TMJ noise was observed three dimensionally. The occlusal plane was used as the standard for these three dimensional measurements. Changes resulting from the use of splints were also observed. The results were as follows:
1. Compared with normal subjects, the maximum value of fluctuation in subjects with TMJ noise for each particular measurement during opening and closing was distributed over a wide area.
2. The change in mandibular movement when the TMJ noise occurred was reproducible.
3. It was possible to divide the subjects with TMJ noise into three groups according to the particular splint used and the resulting noise changes.
4. In each group, the slant change on the occlusal plane was characteristically different when TMJ noise occurred before splints were fitted, and the changes after fitting particular splints were constant.
5. The above findings indicate that three dimensional measurements of slant changes on the occlusal plane when TMJ noise occurs may possibly be an important and useful index when examining subjects with TMJ noise.

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Using subjects conscious of temporomandibular joint sound and normal subjects, the ratio of the masticatory area to the mandibular border movement area was measured. Also, splints were fitted to subjects conscious of TMJ sound and changes of sound and masticatory areas were measured.
1. In normal subjects, the ratio tended to vary little with any of the test foods.
2. In subjects conscious of the TMJ sound, the ratio decreased in the case of all test foods when compared with the normal subjects.
3. In subjects conscious of TMJ sound, it was observed that the TMJ sound occurred in some subjects but not in others during mastication.
4. The decrease in the ratio of the subjects with no TMJ sound during mastication was more outstanding than that of subjects in which TMJ sound occurred during mastication.
5. After fitting splints, the change in the TMJ sound was accompanied by a change in the masticatory area.
6. These findings suggest that the decrease in the mastication area experienced by subjects conscious of TMJ sound, when compared with normal subjects, may be caused by the TMJ sound.

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Powder retentions are widely used in clinical for retaining acrylic resin facing of veneered crown. These retentions show relatively high bond strength and easy manipulation compared with the traditional retention devices of bar, hole, bead, loop and etc.
However, the particle size of powders commercially available are above 250μm and reduced the thickness of facing resin. Thereupon, smaller diameter of powder were trially applied, however, microparticles were submerged under adhesive and undercut effective for retaining resin was lost.
In this research, a new powder retention system adopted pressure sensitive adhesive was studied. The trial adhesive includes volatile solvent like as the traditional adhesives. However, the solvent vapors rapidly and the adhesive applied onto the wax pattern showes pressure sensitivity. Six different sizes of spherical powder were used and the smallest and largest particle size were 90-110μm and 230-250μm respectively.
New powder retention system applied sensitive adhesive exhibited excellent bond strength to photo polimerized composite facing resin and denture base resin. The powder of 110-130μm diameter showed shear bond strength values of above 200kgf/cm² after 30, 000 thermocycles.

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Relations between successive changes of the microvascular architecture and osseous healing in the restorative process of supporting structures of endosseous implants were experimentally investigated on plastic microcasts of blood vessels under SEM. Sixty days after upper incisor extractions of Japanese monkeys (Macaca fuscata), titanium, notch- and screw-typed, and bioceram-anchorpin were implanted. The animals were sacrificed at postoperative 1, 2, 4, 9 weeks, respectively. Acryl plastic was injected via the common carotid arteries. Microvascular casts together with bone element of the maxillae were prepared for SEM as well histological slides for light microscope. One week after implantation, sinusoidal vessels sprouted out of pre-existing vessels including leakages of the injected plastic. Two weeks, these sinusoids began to be sorted out. Newly-formed, stalked bone trabeculae reached the implant surface, where each of them has enlarged as an island-like piece. Four weeks, these pieces have been connected with each other by adhesion. Outside the new bone, blood capillaries sorted out have formed a cylindrical plexus. These successive osseous integration surrounding the implant has continued until about 9 weeks.
In conclusion, it can be said that the period of 4-6 weeks after implantation was most important and significant to be established the osseous integration.

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The purpose of this study is to investigate the effect of the direct current electrical stimulation on surrounding tissue of the intra-osseous implant. The implant was composed of a peripheral hydroxyapatite layer and a central metal which was used as electrodes, and applied 10μA constant direct current. They were implanted in femuls of four guinea pigs.
These results were as follows:
1. When the bone marrow is stimulated electrically with 10μA direct current for 28 days, large amount of bone formation around the implant was seen in wide area.
2. There was a different reaction surrounding tissue between cathode and anode. Around the cathode, bone formation on the surface of the implant was recognized remarkably. Around the anode, little amount of bone formation on the surface of the implant was recognized.
3. The electrical stimulation, with newly developed power unit and electrode, accelerated new bone formation.

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The purpose of this study was to comparatively study and elucidate thecharacteristics of masticatory function of the subjects with complete denture and those with normal natural dentition. The study were carried out on 20 subjects with normal natural dentition and 30 subjects with complete denture having clinically good prognosis. Masticatory movements were analyzed by electromyograph (EMG) and sirognathograph (SGG) when the subjects were chewing peanuts and kamaboko (boiled fish paste).
The results were as follows:
1. The duration of chewing cycle, closing phase, occluding phase, and EMGs burst duration (especially after tooth contact) were significantly longer in the subjects with complete denture.
2. The maximum opening distance was significantly shorter, the maximum opening and closing velocity were significantly slower, in the subjects with complete denture. Further, the standared deviation of the coordinates of the sample points in the occluding phase was indisordered in the subjects with complete denture, and standard deviation of the coordinates of sample points in occluding phase were varied in complete denture wearers.
3. The frontal masticatory pattern tended to unstable and typical tear drop shape pattern was found in about 60% of the subjects with complete denture.
4. Different reactions to the test foods were observed in the subjects with normal natural dentition, while such was not noted in the cases of the subjects with normal natural dentition.
These results was suggest that the masticatory function in the subjects with complete denture were obviously differ from those of normal natural dentition due to the difference in the sensorymotor-system.

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In order to establish diagnostic and treatment system for temporomandibular (TM) disorder patients, data were collected on mandibular border and tapping movements at incisive point and compared with those from the subjects without any TM disorders.
Significant differences on the ratio of left and right sides of maximum lateral deviation, maximum opening amount and length of pathway of lateral border movement were clearly obtained, the values of maximum speed and acceleration of closing phase in tapping movement obtained from TM disorder patients were also different significantly from those in the control subjects.
These findings suggests that those measured indices in this study would be useful for diagnosis of TM disorders.

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Many methods have been clinically applied for the occlusal analysis in the intercuspal position. However, none of these methods are quantitative.
This study described the new software version of the T-Scan system to record and analyze occlusal contact balance in the anterior-posterior and right-left directions. Six time moment statistics and five force moment statistics were calculated in the midsagittal and the incisal axes of the occlusal plane. In the present study, informed consent was obtained from 60 subjects with natural dentitions and from two patients with craniomandibular disorders.
In normal subjects, the time moments and the force moments of occlusal contacts were symmetrical about the midsagittal axis of occlusal plane. The location of the center of effort for the antero-posterior occlusal contacts, which was measured from the incisal axis of occlusal plane, was also in the first molar region. However, any of the above mentioned statistics was abnormal in the patients with craniomandibular disorders.

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It is very important for clinical diagnosis to record and analyze condylar movement in cranio-mandibular disorders. Recently, many devices have been developed for this purpose. These devices can measure precisely condylar movements, but are difficult to manipulate.
We have developed a simple device which substitute a palpation of the posterior aspect of the TMJ. We modified the Cardiokymograph which use electro-magnetic field. The characteristics of this device are the use of a frequency-variable crystal-controlled osillator, and the application of the coil itself which is a part of the osillator as a probe.
We tested many electrical characteristics of this device and assured the effectiveness, that is, sensitivity, derectivity, frequency response characteristic, transient response characteristic, and temperature response characteristic.
We tried to insert a probe into the external auditory meatus, and record condylar movement as a positional change of the skin.
It seems to suggest that our device can record a feature of condylar movement.

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This study was made to measure non-invasively the deep temperature of the ternporomandibular joint joint [TMJ] region at rest. The transcutaneous probe making use of zeroheat-flow method was utilized for the deep thermometry.
The following results were obtained,
1. In 20 normal male subjects, no differences of the deep temperature were recognizedbetween the right and the left TMJ regions.
2. In 10 patients with temporomandibular disorders, the deep temperature of the symptomatic TMJ side was significantly higher than that of asymptomatic side.

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A light-cured acrylic adhesive for fixing resin retention devices to the wax pattern was prepared. The adhesive consisted of trimethylolpropane triacrylate, 2-ethylhexyl acrylate, benzoin methyl ether,
p-dimethylaminobenzaldehyde and p-methoxyphenol. The adhesive could be cured within 20 sec not only by an UV photo-curing unit but by a visible-light source with a xenon lamp. The adhesive and retention beads burned out after about an hour in the electric furnace at 400°C. The metal specimens with retention devices were cast in Ag-Pd-Cu-Au alloy with the use of two types of retention beads adhesive. The light-cured adhesive was superior to the conventional one in handling and some other properties. This adhesive may be used to fabricate composite veneered prostheses with minimum errors in laboratory procedure.

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We constructed a small number superposition graph by computer program on a cephalometric laminagraph of five adult men and five periodontal patients who haveall their teeth of maxillo-mandibular. Research was done on the sideway movements of the non-working side of the condyle which are fixed to be 1mm, 2mm and 3mm quantitative lateral movement in anterior.
These results are as follows:
1. The research of the movement of the condyle was on the basis of condylar top and condylar center. The condylar movement with right and left side quantitative lateral movement of the adult men indicated a distinct straight line type. But, the periodontal patients indicated a distinct zigzag line type. However, the moving condition of two measuring points on both subjects were much alike.
2. In spite of the condition of the occlusal surface of periodontal patients are different from that of adult men, it could be proved that the moving type of the condylar with the lateral movement is a bodily shift.
3. For both much and little quantity of lateral movement, the degree of moving obliquely of periodontal patients' condylar was less than that of the adult men's condylar.
4. Doubted that the difference of occlusal condition between periodontal patients and adult men were chosen on this study.

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We have been studied the characteristics of protein components in gingival crevicular fluid (GCF) with isoelectric focusing technique. The purpose of this study was to investigate the relationship between those proteins and clinical findings such as Gingival Index (Loe & Sillness), Pocket depth, Plaque Index (Quigley & Hein), Gingival Bleeding Index and Bone Index. GCF, serum and mixed saliva collected from the same subject were analyzed, and following results were obtained. The patterns of protein bands in GCF were similar to those in serum but different from mixed saliva, and the pI of main protein band of GCF and serum were 4.9. No apparent difference was observed on the patterns between clinicaly healthy gingiva and those received periodontal disease. Protein patterns were compared with the before mentioned clinical findings and GCF volume. Main protein bands were observed on cathode side (pI 8.0-9.0) at the patterns against Gingival Index:0-1 or>2, Gingival Bleeding Index:+or-, Pocket Depth:0-1or>2 and Bone Index:1or>3. It was suggested that the study of the proteins on cathode side is important.

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A new digital image processing system to observe oral actions is proposed. The system provides analyses of motion pictures along with other physiological signals. The major components are a video tape recorder, a digital image processor, a percept scope, a CCD camera, an A/D converter and a personal computer. Five reference points were marked on the lip and eyeglasses of 9 adult subjects. Lip movements were recorded and analyzed using thesystem when uttering five vowels and Ika, sa, ta, ha, ra, ma, pa, bal.
Results:
1. Positions of the lip when uttering five vowels were clearly classified.
2. Active articulatory movements of the lip were not recognized when uttering consonants-nantsb|k, s, t, h, r |. It seemed lip movements were dependent on tongue and mandibular movements. Downward and rearward movements of the upper lip, and upward and forward movements of the lower lip were observed when uttering consonants|m, p, b|.

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In selecting and arranging anterior artificial teeth for edentulous patients, it is necessary to consider their sex, personality, age and other factors. The relation of upper and lower lip lines to incisal edge has been one of the standards for the selection and the arrangement of anterior artificial teeth. The purpose of this report was to establish andto evaluate decision bases for the selection and arrangement. We recorded and measured the exposure rate of anterior natural teeth (48 men, 46 women) during function, such as smile, pronunciaion, by means of the image analysis.
Following results were obtained.
1. As the age of patients increased, upper anterior teeth appeared less than lower's.
2. Differences in exposure ratio between upper and lower teeth were found more remarkable in smiling rather than in pronunciation.

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The condition of palatal mucosa caused by wearing a maxillary complete denture closely resembles a closed hydrostatic system.
To clarify the viscoelastic properties of the palatal mucosa under such a condition, we measured as a function of the degree of denture displacement during biting movements.
For this work, we developped three dimensional movement-measuring equipment.
The following results were obtained:
1. The displacement of the maxillary complete denture during biting movements (loading and unloading of occlusal forces) could be approximated by an empirical formula of expornential function.This formula expressed the delayed elasticity characteristics of the viscoelasticity of the palatal mucosa.
2. Observation of the denture's displacement revealed that the movement of the palatal mucosa after occlusal forces are unloaded could be regarded as creep according to a Voigtian two-element model.
3. Denture displacement differed between occlusal force loading and unloading: dentures took longer to return to the original position during occlusal force unloading.
4. This time delay, indicating the degree of delayed elasticity of the palatal mucosa, was substantially shorter than the reported value based on local compression tests. Our study clearly shows that when a maxillary complete denture is worn, movement of the palatal mucosa approximates a closed system, and differs from localized open systems.

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This article was aimed to propose a new concept on evaluating electromyographic activities of masticatory muscles during chewing movements viewed from the standpoint of motor skill.
Correlation coefficients between the ratio of lateral distance to ten vertical level set at 0.5mm to 5.0mm with 0.5mm step from the end of closing phase and activities of bilateral masseter, anterior and posterior temporalis in each chewing stroke were evaluated using raisin, peanut, soft and hard testing gum in five subjects.
Habitual chewing side always demonstrated less numbers of subjects who showed high correlation coefficients especially in the case of soft testing gum.

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