The purpose of this study is to reveal the relation between condition ofstomatognathic system and condition of whole body.
First of all, in this study taking notice of human posture especially about right standing posture, so we have examined influence of occlusal interference on right standing posture by using analyzing system of the locus of the body's gravity center.
The subjects were consist of nine normal adult men and measured with eye closed, closed feet position for 20 minutes.
As a result, Occlusal interference has made the diameter, the total length and the area ofthe locus followed by the body's gravity center tend to large value of it's late.

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Many of soft lining materials are available at present, but they are different from each other in physical and mechanical properties.
In order to examine the feasibility of soft lining materials, properties of the materials were examined through static creep test and pressure distribution for typical materials which are applied treatments when a compressive stress of 0.5kg/cm2 was applied.
The results were as follows:
1) The variation of pressures between measurement points was decreased if the tested materials, which were mixed for three hours, were contained between plates.
2) The tested materials were classified into two groups according to the instantaneous elasticity. Group A has 2.0-4.0-106 dyne/cm2 and group B has 6.0-7.0-106 dyne/cm2.
The variation of pressures between measurement points of group A was smaller than that of group B.
3) The variation of pressures between measurement points of group A was decreased when the specimen was thick. On the other hand, that of group B did not change with thickness of specimen.
4) The variation of pressures between measurement points of Visco-gel and Coe-comfort was decreased with time dependency. On the other hand, that of Hydro-cast and Softone was increased.

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We surveyed various kinds of dowel-cores of the patients at the Tsurumi University Dental Clinic during the nine month period, March to November 1986, in order to know thefrequency in use of several dowel and core methods available in practice.
The results were as follows:
1. Cast metal dowel and cores were fabricated in the highest rate (68.2%) and followedby plastic materials (28.2%).
2. In cast dowel and cores, Ag-Pd-Au alloy was used in the highest rate (85.7%) and followed by Ag-Sn-Zn alloy (14.3%).
3. In plastic materials, composite resin dowel and cores amounted to 98.8% and dental cement 9.2%. Amalgam corewas not used even in only one case.
4. In the severe situation like total loss of coronal tooth structure, cast dowel and cores were especially indicated.

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The purpose of this study is to evaluate the masticatory function of the complete denture wearers by examining the foods patients can eat with the dentures. A qustionnaire with listings of 35 foods was given to 39 patients who have been wearing newly made denture for 6 months and were asked to select the answer out of the following 5 categories.
mark point
*can be eaten easily 2 2
can be eaten with difficulty 1 1
cannot be eaten 0 0
I do not eat it because I dislike it Δ 0
I have never eaten it since wearing of denture 0
The results were as follows:
1. Each answer was given a score (2, 1, 0). 35 foods were classified into 5 grades showing the difficulty by each total scores.
2. The“ standard masticatory ability of complete denture wearers ” was established as the diagnostic criteria by calculating the rate of food-taking ability in each grade.
3. Masticatory ability of each individual was shown as the “ masticatory score”.
4. Applying this qustionnaire to the alveoplasty case, the rate of food-taking ability and the masticatory score were correlated with masticatory ability and it was suggested that the qustionnaire was useful for the evaluation of the masticatory function.

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The purpose of this study was to investigate the correlation between occlusal plane angle and other angular measurements of dentofacial morphology by cephalometric analy
Subjects consisted of fiftythree young adults with a mean age of 26 years.
The following results were obtained:
1. SN-Occlusal plane angle was 14.4±4.87 degree.
2. SN-Occlusal plane angle showed a positive correlation to SN-Mandibular plane angle with a coeffient of 0.662 (p<0.005), and a negative correlation to SN-Mm with a coeffient of 0.527 (p<0.05).
3. Subjects were separated into three groupes; less than -S. D., from-1S. D. to+1S. D. and larger than +1S. D. of SN-Occlusal plane angle. The mean angular measurements of the three respective groups were then compared. Mean values of SN-Mandibular plane angle and Mm-Occlusal plane angle of the three groups showed significant difference to each other (p<0.05).
It was shown that occlusal plane angle correlated with both mandibular plane angle and masseter muscle orientation.

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We investigated the bonding strength of hardened plastic teeth to denture base acrylic resin. Two types of hardened plastic teeth conventional plastic teeth and porcelain teeth were used. As the denture base acrylic resin, conventional heat-curing type and heatcuring type containing 4-META adhesive monomer were used. Test specimens were fabricated under four tooth ridge lap treatments, 1) no treatment, 2) grinding, 3) monomer application, and 4) grinding and monomer application. Then bonding strengths were measured according to JIS specification.
The bonding strength of conventional plastic teeth to denture base acrylic resin did not differed with denture base acrylic resin and tooth ridge lap treatments. Also the variation coefficient of bonding strength of conventional plastic teeth did not vary with denture base acrylic resin and the treatments. The bonding strength of hardened plastic teeth to denture base acrylic resin were the same of larger than that of conventional plastic teeth to denture base acrylic resin. The bonding strengths of hardened plastic teeth to denture base acrylic resin were increased with tooth ridge lap treatments, but the variation coefficient of bonding strength of hardened plastic teeth were less varied with the treatments. These results were clearly observed in the use of denture base acrylic resin containing 4-META.

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For the purpose of making a comparison between bulk-photo-polymerized resins and composite resins, getting clinically acceptable visible-light cured veneering resins with excellent properties and investigating the effects of two types fillers on physical properties of veneering resins, Knoop hardness numbers, compressive and transverse strength of the experimental light cured resins were measured.
Knoop hardness numbers of the composite resins were nearly the same characters as bulkphoto- polymerized resins.
Physical properties of composite resins were superior to those of bulk-photo-polymerized resins. But characters of polymers were under the influence of curing behavior of monomers.
Mechanical properties of composite resins with visible-UV double initiator system stood comparison with those of visible-light cured and heated composites.
Compressive strengths obtained from composites with silanized filler were stronger than those obtained from composites with untreated filler, while the transvers strengths were the opposition. Composites with untreated filler were not water-resistant.

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Electromyographic studies have been conducted on the time factors of the silent periods that occur during chin tapping with a view to utilizing these factors as criteria for prosthetic treatment.
In the present study, the authors examined the relationship between the time factors of such silent periods and the activity of temporal muscles, masseter muscles, and bite force in normal subjects.
The findings are as follows:
1. The time factors of the chin tap silent periods varied greatly depending upon subjects.
2. At a time when the bite force of each subject reached the maximum, there was a great difference in their muscle activity, ranging from 40 to 190μv.
3. Any significant difference was not observed in the relations between the time factors of the chin tap silent periods and muscle activity.
4. The relations between the time factors of the chin tap silent periods and bite force showed highly significant differences with respect to latency (L), duration (D) and L+D. As the bite force decreased, L shortened while D and L+D lengthened.
5. Patients with temporomandibular joint (TMJ) dysfunction have a weak bite force. However, it remains to be seen whether changes in the time factors of the silent period in the people examined are comparable to those in the patients with TMJ dysfunction.

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The flow characteristic of an impression material is one of important factors in the selection of suitable materials for edentulous impression procedures. The purpose of this study was to compare the degree of flow obtained from several types of impression materials (zinc oxide-eugenol impression materials, polysulfide rubber impression materials, silicone rubber impression materials) by the parallel plate viscometer. The viscometer is used to measure the spread radius of samples (a volume of 0.5 cm³) between two parallel flat plates loaded by a 575-gram weight at 1, 10, 60, 100 seconds after loading had begun. The load was applied initially at 90 seconds after mixing had begun. All samples were mixed according to the manufacture's recommendations.
The finding was that zinc oxide-eugenol impression materials (ADAS No.16 type 1) and addition-type silicone rubber impression materials (ADAS No.19 low viscosity type) had high flow compared to condensation-type silicone rubber impression materials (ADAS No.19 medium viscosity type).

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Bonding between laboratory light-cured composite and surface treated Au-Ag-Pd alloy was investigated using newly developed 4-META/MMA-TBB opaque resin. Shear bond strength after 20, 000 thermocycles obtained from heated alloy with this method was 25.1 MPa. Ion-coated specimen showed 25.6 MPa after 50, 000 thermocycles with decrease in bond strength being small. Ferric chloride treated specimen, however, detached from alloy-opaque interface with lowest bond strength. An X-ray photo-electron spectroscopic analysis of ferric chloride treated specimen reveaed increase in silver chloride and oxide, which affected bonding between opaque resin and Au-Ag-Pd alloy.

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The purpose of this study was to investigate the effect of tissue-conditioners and relining resin monomers on the bending strength of denture base resin.
The specimens, which were treated with tissue-conditioners or relining resin monomers, were kept under the various transverse loads for three days, and the bending strength of the specimens were examined. Three denture base resins, three direct-relining resin monomers and eight tissue-conditioners were used.
The bending strength of the specimens which were relined tissue-conditioner and not applied the transverse load, was not changed statistically. That of PMMA and polysulfone resin (PSF) applied the transverse load was significantly decreased by relining the tissue-conditioner, while that of polyethersulfone resin (PES) was not changed statistically. The specimens of PSF and PES applied the direct-relining resin monomer, were cracked or fractured by only applying the transverse load, while those of PMMA were not changed visually.
It was concluded from results that it is important to consider about denture base resin materials when tissue-conditioners or relining resins were used in clinic.

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The purpose of this study is to investigate the influence of setting expansion and thermal expansion of the phosphate-bonded investment on the fitness of cast claspsfabricated by a superelastic Ni-Ti alloy. Investment models were made from the columnar stainless-steel model supposed the abutment tooth the various dilusion colloidal silica solutions.Cast clasps were fabricated using by using a superelastic Ni-Ti alloy, then dimensional changes at the tip and mid-point of clasp arm between before and after fitness of cast clasps to the stainless-steel model were measured by the using of a profile projector. In addition, setting expansion and thermal expansion of investments were measured.
Results were as follows:(1) Setting expansion increased with the increase of the concentration of colloidal silca solution, however thermal expansion kept constant.(2) Cast clasps fabrcated by using the investment model with 1.6% of setting expansion and 1.0% of thermal expansion showed the best fitness.

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The objective of this study is to explain mathematically the effect of curvature of horizontal balancing condylar path on that of tooth path.
Conclusions from the calculation are;
1. Curvature of tooth path increases similar to that of horizontal balancing condylar path.
2. The relation of curvature between horizontal balancing condylar path and tooth path is hardly affected, even if the direction of balancing condyle path and the inclination of sagittal incisal path altered.
3. But, the direction of working condylar path, especially on posterior-external-upper laterotrusion, affects remarkably the relation of curvature of horizontal balancing condylar path and tooth path.
4. Curvature of horizontal balancing condylar path affects greater that of tooth path than that of sagittal condylar path.

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Margin-Checker Type I has been developed to investigate the marginal fitness of crowns clinically. By the use of Margin-Checker Type I, delivered 315 crowns were examined.
Following results were obtained.
1. Margin-Checker Type I showed the exellent availability to examine the marginal fitness of crowns clinically.
2. The crowns of 100 μm or less overhang value accounted for 82.7% of all the examined ones.

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In order to evaluate the strength of castable glass ceramic (DICOR^TM) crowns and bridges, compressive strength tests were performed on the crowns of maxillary central incisors and the three unit maxillary anterior fixed partial dentures.
The crowns were made under the three conditions as follows: I. 4 times firing of DICOR shading porcelain, II. 4 times firing without applying DICOR shading porcelain, III. without firing of the shading.
Loads were applied at 4 points of the crowns as follows: A. center of the lingual surface, B. linguoincisal edge, C. linguogingival ridge, D. distal edge.
The bridges were loaded at the center of the pontics.
Every specimen was loaded from the direction of 45° from the tooth axis by using an Instron testing machine at a crosshead speed of 0.5 mm/min. The load at fracture and the type of failure were recorded.
The results obtained were as follows:
1. Mean values of the fracture loads of crowns were, 135.3kg at loading point A, 34.0kg at B, 60.7kg at C, and 31.8 kg at D.
2. Mean value of the fracture load of bridges was 50.0kg.
3. The application of shading porcelain or the firing procedure of the shading had no influence on the strength of the crown. Shading porcelain fused firmly to the crowns.
4. The DICOR crown had high stability of strength. And it was suggested that the DICOR bridge in this study could be adequate to withstand normal occlusal loads.

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Ten patients received augmentation of the deficient mandibular alveolar ridgesusing particulate hydroxyapatite (HAP). Investigations were undertaken to evaluate the augmented ridge form during a postoperative period from 6 to 30 months. No serious troubles attributable to the use of the implant and the surgical procedures were observed. The mandibular complete dentures constructed on postaugmented ridges were clinically judged to be more successfull with the use of the surgical stent. Measurement of vertical ridge heights with panoramic radiographs showed that the augmented portions of the alveolar ridges were on the average of 59% higher than their preoperative heights. Over a period of 30 months, beginning 1 month after augmentation, longitudinal reduction of ridge heights was approximately 6%. An average enlargement of 32% was observed in measurements of the denture-bearing area. The contour of the augmented alveolar ridges showed an increase of height at the lingual area and of breadth at the buccal area, which may provide increased retention and stability for complete dentures. The placement and ligation of the surgical stent proved beneficial to the HAP augmentation.
From these findings, the HAP augmentation appears to be effective in improving the ridge form and denture success, provided that consideration is given to prosthodontics and the surgical stent is used.

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The following is a list of the test results using the three dimensional measurement system to measure a denture base as compared to the method used up until now.
1. The new measuring method is a remarkable improvement upon the measuring method used up until now.
2. The new measuring method takes about one fourth the time to measure as compared to the method used up until now.
3. The precision obtained using the new measuring system will not change much with experience.
4. Using the new method, measuring precision of the X axis direction was 5μm, the Y axis direction was 5μm, and the Z axis direction was 1μm.

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Using subjects conscious of tempromandibular joint sounds, three-dismensional measurements were taken within the movement of the mandibular border at points where the sounds occured during opening and closing of the mouth. Changes in sound were also observed after fitting splints. Similar measurements were also taken on patients diagnosed as having a TMJ dysfunction.
1. The mandibular position when sound occured in subjects varied greatly between opening and closing of the mouth.
2. From the characteristic mandibular positions where the TMJ sounds occurred in individuals during opening and closing of the mouth, it was possible to divide the subjects into five groups. Splints used were also different according to these characteristics.
3. When the anterior repositioning splint was used on subject in the early phase of opening the mouth, the phase became even earlier.
4. When the stabilization splint was used during opening of the mouth for two of the group with different characterisics, the extent of position change in each group proved to be different.
5. A particular relationship was observed between the changing sound position and the splint fitting, which suggests a relationship between the sound position and the cause of the TMJ sound and the effect of splint therapy.

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There are close relationships between craniofacial form and activity of human jaw muscles, and the reaction forces (bite forces) they produce at the teeth and articular surface of the temporomandibular joints. To define these associations in human jaw function, correlation between these components are necessary.
The lateral cephalometric radiographs were used for classification of craniofacial form. One loadcell was held in a cast metal framework located the center of first molar. A matching mandibular framework transmitted loads to the cell. Intra-oral forces were then recorded in subjects who carried out repeated clenching tasks under two force vectors. Simultaneous recording of the electrical activity in selected jaw muscle were used to observe relative changes in their contribution to bite forces.
Craniofacial form was classified the short face group and long face group under the orthodontic view points, and was found significant difference between these two group. Masseter and anterior part of temporal muscle was harmonized to get the bite force, and the exponential curve was identified between both muscle activity and bite force.
Significant correlation between medial pterygoid muscle activity and bite force could not be identified, and this muscle activity revealed much variability.

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The purpose of this study is to investigate the influence of two marginal shapes of abutment teeth (shoulder type and chamfer type) on the toughness of all ceramic crowns, by means of finite element method and the model tests.
The following results were obtained;
1. Tensile, bending and shear strengths of the Cerestore materials used in the model tests were higher than those of conventional porcelain materials.
2. In the model tests for breaking loads of all ceramic crowns, the models corresponding to abutment teeth with metal core showed higher effect than those corresponding to vital abutment teeth.
On the marginal difference, the strength of full shoulder types were higher than those of chamfer types in the models corresponding to vital abutment teeth, while there was no significant difference between two types in the models corresponding to abutment teeth with metal core.
3. Using finite element method, there was the heavy tensile stress around the loading point of all ceramic crown with vital abutment teeth, which approximated to tensile strength of Cerestore material, the value was approximately three times of that in abutment teeth with metal core.

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The purpose of this study is to investigate the relation between the thickness of silicone film obtained by fitness test and the pressure distribution under the denture base. Fitness tests were made on the simulation models at various amount of loads, measuring the pressure by diaphragm pressure sensors.
The results obtained were as follows:
1. Under the conditions of this experiment, pressure distribution during fitness test got constant within 60 seconds.
2. Pressure distribution was made more uniform at fitness test.
3. Correlation was observed between the pressure and the thickness of silicone film.
4. On Model 1, simulated hard mucose membrane, they had hyperbolic correlation, and on Model 2, medium hard mucose membrane, they had linear correlation.
5. On the simulation model with constant displaceability, regression coefficient was not largely affected by the location of sensors.
6. Relation between the pressure and the thickness of silicone film affected by the location of displaceability.
From the results described above, it was proved that the pressure distribution under the denture base could be estimated by the fitness test, and on the clinical judgement of fitness test, it is necessary to consider the difference and the location of displaceability of mucose membrane.

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Kinematic axis point is known to be one of the posterior reference points of the mandible. We can identify it by its characteristic that it moves reciprocally in sagittal border movement. But no one has investigated how far its estimated location depends on the sagittal movement used. Therefore, we experimentally investigated the reproducibility of the estimated location of the kinematic axis point.
Firstly we investigated the variation of the locations estimated by three voluntary sagittal border movement. We evaluated it by the average value of three inter-location-distances, which resulted in 0.77±0.55 [mm] on the average of twenty condyles. As for each condyle, a point with the average location of three measurements appeared to be appropriate for an approximation of the kinematic axis point.
Secondly we compared the location estimated by non-border movement with that by the border movement. The results showed that the difference between the two locations was affected by the following two factors: 1) moved distance of the condyle, 2) the difference between rotational angles of the mandible at the same condylar position. When either the moved distance was more than 70% of the maximum value, or the difference of the rotational angle was more than 10 degrees, the difference between the two locations was small.

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