Various techniques for complete denture construction have been used.
However, in the traditional technique, a functional ridge form can't be made, due to using a finger pressure.
In other technique, special device or instruments forthose system need to use.
We have developed a technique for complete dentureconstruction, that a functional ridge form could be made, and that conventional device or instruments are used.
The characteristics of this technique are asfollows;
1. It is easy to make diagnostic cast and make maxillomandibullar relation record, due to use a double impression tray. 2. Lower final impression is made after upper final impression and maxillomandibular relation record have been made.
3. Occlusal force is used as impression pressure.

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For the an acoustic relation between TM Disorders and the function of hearing organs by tympanometry in three groups: healthy subjects (HEALTHY), subjects with click (CLICK) and TMD patients (TMD). We examined these absolute values, and obtained the following conclusion.
1. Regarding static compliance, there was a significant diffrence between HEALTHY and TMD, and also between CLICK and TMD, with a 1% hazzard rate.
2. Regarding impedance, there was a signifficant diffrence between HEALTHY and CLICK, (CLICK) and TMD, with a 5% hazzard rate, and also between HEALTHY and TMD with a 1% hazzard rate.
3. Regarding press and earclearance, there was a signifficant diffrence between HEALTHY and CLICK, with a 1% hazzard rate.
4. Regarding tympanogram, all of HEALTHY showed a symmetrical Type-A on both sides. In CLICK, there were 8 cases of Type-A and 17 cases of Type-As on both sides, all showing symmetricality. But in TMD, only three cases, one of the Type-A and two of the Type-As, showed symmetricality; all the rest ofthe 12 cases were asymmetrical.

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The following conclusions were obtained by observing the shape of abutment teethin various regions on plaster models which had been used for fabrication of single-unit, prosthetic restorations of full-coverage crowns.
The average value for the mesiodistal taper of the maxillary teeth tended to increase in the posterior teeth.
The average value for the faciolingual taper of the maxillary teeth were larger than those for the mesiodistal taper. In the mandible, the valueof the taper from the central incisors to the second premolars were about 15° and the molar region was 25°.
The height of the abutment teeth was greater for the canines and central incisors, it became less moving towards the posterior teeth.
The clinical preparation of abutment teeth, there was a small taper in the anterior teeth where the height of the crown was large, while the taper tended to become larger in the posterior teeth where the height of the crown was smaller.

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In the first report, the two dimensional finite element analysis was performed on the bridge model through a computer in order to learn the effect of such two factors as the resorption of the alveolar bone and the number of abutment teeth against the stress distribution of the supporting tissue of the brige whitch is subject to the occlusal force. Furthermore, the results of the finite element analysis under vertical load were compared between the three and the two dimensional models of single rooted tooth in order to study the relation between the threedimensional resorption state of the alveolar bone and the two dimensional model.The models used in study, however, were extremely simplified. Moreover, the periodontal membrane was not modeled and the influence of the lateral load was not considered. Based on these background, in this report, more practical three dimensional model was created including the periodontal membrane. In addition, two two-dimensional models of bucco-lingual and mesiodistal cross sections of three dimentional one were created.
The loading direction and the degree of alveolarbone defect were varied by each model. The load was given vertically, bucco-laterally and lingual-laterally. Alveolar bone defect were three cases of 0, 1/3 and2/3 defect of the root length. The comparison of the results of the finite element analysis performed on the total of 18 cases and those of first report resulted in as follows.
1. The periodontal membrane has stress breaking effect on the alveolar bone surrounding teeth.
2. In the extremely-stressed part, the three dimensional model tends to show higher stress value than the two dimensional one.
3. In the laterally loaded case, the load part generates tensile stress and opposite side, compressive stress around the ceavical part. Around the apical part, the two stresses are reversed.
4. As bone defect progresses, the stress to be generated increases. For exsample, equivalent stresses generated atthe periodontal membrane in the vertically-loaded three dimensional model were 1.0, about 1.5 and about 2.3 in terms of 0, 1/3 and 2/3 defect respectively.

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In this study, 12 removable partial dentures with rotational path clasping system were applied in the clinical field. The authors examined the retention of the dentures, mesiodistal distance of edentulous space, and undercut of rigid retentive component and inclination of mesial surface of posterior abutment tooth. Thefollowing results were obtained:
1. Retention of 12 dentures was varied from187 g to 1, 380g.
2. Retention decreased in the order when mesio-distal distance of edentulous space was changed 10.9 mm to 27.7 mm, and the coefficient of correlation between retention and mesiodistal distance was-0.56.
3. Retentionshowed a tendency to increase in order when inclination of mesial surface was changed 0° to 51°, and the coefficient of correlation between retention and inclination of mesial surface was +0.47. The coefficient of correlation between retention and undercut of rigid retentive component was +0.13.
4. Long mesio-distal distance as well as small inclination of mesial surface are present inthree patients who answered that their dentures were sometimes displaced during mastication.
These results showed that the retention of rotational path clasping system was influenced not only by conventional clasp, mesio-distal distanceof edentulous space and undercut of rigid retentive component but also by inclination of mesial surface of posterior abutment tooth.

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Location of the intermediate abutment, length of span and number of abutments were changed in three-, four- and five-unit fixed partial dentures having two or three abutments and their influences on retentive forces of each abutment were measured after repeating load at one-point (the center) and three-points (two moreexternal points) of occluding faces of fixed partial dentures.
The results were as follows:
1. When repeating load was applied at the center of five-unit fixed partial dentures having three abutments, the intermediate abutment indicated the lowest retentive forces of all abutments.
2. Location of the intermediate abutment between two external abutments was significant for the retentionof each abutment.
3. Fixed partial dentures having two abutments became deflected in proportionally as the span between the abutments became longer. The amount of deflection was significant for the retention of each abutment.
4. Five-unit fixed partial dentures having two abutments indicated the lowest retentive forces of all fixed partial dentures examined.
5. Addition of one more abutment to four-unit fixed partial dentures having two abutments was not always effective in improvement of the retention of fixed partial dentures.
6. Numberof loading points was significant for the retention of the fixed partial dentures.

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Recently, denture stomatitis was found in the oral mucosa of most denture wearers. It is generally accepted that the significant cause of denture stomatitis areinfection with Candida albicans. Dentists indicate that the denture plaque with Candida albicans is removed from denture surface by both mechanical denture cleaning and chemical denture cleaning. The color in the oral mucosa depends on the infection such as gingivitis and denture stomatitis.
The purpose of this study is to examine the effect of the denture cleaner on the oral mucosa in the Candida-induced denture stomatitis by the change of the color in the oral mucosa.
The results were as follows:
1. The denture stomatitis became well after chemical denture cleaner was used. Especially, the infection at the posterior ofpalate were not found.
2. The infection region have 2.8 R-5.1R in Hue, 5.7-6.1 in Chroma, 6.8-7.7 in Value. On the contrary, the non-infection region have3.8R-7.5 R in Hue, 6.4-6.9 in Chroma, 4.0-6.4 in Value.
3. The color differencebetween the denture-bearing mucosa when no chemical denture cleaner was used andthat when denture cleaner was used, provided a method for estimating the effect of the denture cleaner. The greater color difference were found at the palate.

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In order to establish an objectively evaluating method for masticatory function an automatic masticatory movement analyzing system was developed. Using this system the differences in the masticatory movement between normal subjects and craniomandibular disorder (CMD) patients were analyzed.
1. A system was developed that can change the analog signals of masticatory movement to digital signals, establish threshold value, and automatically evaluate the average path of the opening and closing movement and the rhythm of the opening, closing and occluding phase.
2. No significant differences were found in the opening, closing, andoccluding time when the system or the degimatic caliper was used in analyzing masticatory strokes.
3. The ten strokes beginning the fifth stroke of chewing gum were the most stable in both rhythm and path.
4. There were significant differences between CMD patients and normal subjects in the indicators for the stability of rhythm and path.
5. The stability of rhythm and path was considered normal if the indicators were within one standard deviation, and for the rhythm, if 3 out of 4 indicators, and for the path, if 2 out of 3 indicators were within normal range.
6. A radar chart was formulated for an objective evaluation of masticatory function.

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In order to find the difference between the habitual chewing side and the nonhabitual chewing side during mastication, the 5th stroke to the 14th stroke of 20 normal subjects masticating chewing gum were analyzed using the automatic masticatory movement analyzing system, and the opening distance, average path, rhythm, and the stability of chewing path and rhythm were calculated and compared between the two sides.
1. The average path can be classified into 2 classes. Both the habitual and the nonhabitual chewing sides showed similar pattern in almost all the subjects.
2. No significant differences were found in the opening distance between the habitual and non-habitual chewing sides.
3. There were significant differences in the stability of chewing path between the two sides with the non-habitual chewing side being less stable.
4. No significant differences were found in the chewing rhythm between the two sides. Though differences among individual subjects were found.
5. There were differences in the stability of chewing rhythm between the two sides in 14 out of 20 cases with the non-habitual chewing side being less stable.
6. It was recognized that the non-habitual chewing side is less stable than the habitual chewing side in both path and rhythm. Thus functionally the two sides differ.

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The histopathological initial changes in the denture supporting tissues were investigated in relation to the impression pressure. The hard palate of adult Wistar rat was employed as experimental area. The experimental area was examined histopathologically and histometrically up to 7 days after the insertion of experimental dentures.
Three diverse impression procedures were employed to make each non-pressure, moderatepressure and heavy-pressure impression. The mean maximumimpression pressure for these impressions were 0.0, 9.4 and 22.4g/mm², and the mean final impression pressure for these impressions were 0.0, 0.2 and0.5g/mm², respectively. The pressure which is equivalent to the impression pressure was applied to the denture supporting tissues with the wearing ofthe denture constructed on the cast poured into each impressions.
There was no significant changes during the experimental period in the tissues under the denture which was constructed on the cast poured into non-pressure impression. The histopathological changes in the tissues under the denture which was constructed on the cast poured into moderate or heavy pressure impression came out earlier and more severe with the increase of the pressure. The connective and bone tissues indicated histopathological reaction in advance of the changes observed in the epithelial layer except for epithelial ridges.

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At the present time, there are several Jaw movement analyzers that can analyze the condylar movements in six degrees-of-freedom. All of them are mounted between maxillary and mandibular face-bows. And all investigators study jaw movements on assumption that the human body is rigid. But the occlusal force causes the displacement of teeth and deformation of bones. In this study, we measured the displacement of maxillary dental arch during clenching with two occlusal conditions in three subjects, and evaluated its effects on analysis of Jaw movements quantitatively. We recorded the clenching for three times with each condition in each subject. The results are as follow:
1. Maxillary dental arch displacement during clenching in the intercuspal positionaveraged 29±11 μm superiorly, 17±23 μm at the right side and 5±14 μm anteriorly at bilateral first molars. And during clenching on the unilateral first-molar pivot, they averaged 35± 18 μm superiorly, 5±22 μm medially and 21±27 μm anteriorly at the maxillary first molar of the working-side.
2. In the vertical direction, the maxillary tooth arch displacement showed the condyle more inferior than the real position. Those values were 63±47 μm at both condyles (clenchig in the intercuspal position) and 31±65 μm at the working-side condyle (clenching on the pivot).

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The prerequisite to enhance the function of the free-end saddle R. P. D. is to diminish the denture dynamics in mastication. The authors have already reported the evaluating methods of the denture dynamics in the free-end R. P. D.'s with various retainers.
In the previous reports, the denture dynamics were mainly affected by the retainers used; the more rigidity the retainers were connected to the abutment teeth, the less the denture dynamics were obtained. What is the key to diminish the denture dynamics? and what is the main characteristics of the cone-crown-telescope, which was revealed to have the least dynamics among the various retainers?
So, we have conducted a study on the connecting rigidity which may seem to be the main characteristics of the cone-crown-telescope on the bench model assembly.
Following results were obtained:
1. The greatest value of the connecting rigidity was obtained in the cone-crown-telescope, then followed the R. P. P. I., the R. P. I. by Kratochvil, the R. P. I. by Krol, to the R.P.I. and the Aker's clasp without the guiding function in sequence.
2. It was clearly indicated that the guiding surface/guiding plate parallelism between the abutment teeth and the retainers played the most important role in obtaining the connecting rigidity in the clasp designed R. P. D.'s.
3. An ordinary refractory model method for obtaining the guiding/surface guiding plate function revealed to fail the genuine connecting rigidity matching for the one in the conecrown-telescope.

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The objective of this study is to explain mathematically the effect of curvature of horizontal balancing condylar path and direction of working condylar path on tooth path. Conclusions from the calculation were;
1. The direction of working condylar path, especially on posterior-external-superior laterotrusion, affected remarkably the relation of curvature of horizontal balancing condylar path and tooth path.
2. As the direction of working condylar path was made greater toward posterior-external-superior, curvature of tooth path increased similar to that of horizontal balancing condylar path.
From the facts described above, through another attempt of condylar path on the human lateral excurtion, the following results were obtained;
3. On the human lateral excursion, it was very little case that put larger curvature of horizontal balancing condylar path and working condylar path in posterior-external-superior direction together.
4. For this reason, it is clinically almost unnecessary to reproduce curvature of horizontal balancing condylar path on articulator.

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Light-cured adhesive opaque resins with high bond strength were prepared with the use of 4-methacryloxyethyl trimellitate anhydride (4-META), eleven methacrylate monomers and composite pigment. The purpose of this study was to investigate the relation between the monomer composition and the bond strength of the opaque resin. The shear bond strengths of ethyleneglycol dimethacrylate (1 G), diethyleneglycol dimethacrylate (2 G) and triethyleneglycol dimethacrylate (3 G)-based opaque resins were superior to those of other monomerbased opaque resins after thermocycles. A methyl methacrylate (MMA)-based opaque resin showed poor bond ability. 1, 6-bis (methacryloxy-2-ethoxycarbonylamino)-2, 4, 4-trimethylhexane (UDMA) effectively provided viscosity to the compositions. The prepared opaque resin, which consisted of 4-META/MMA-3 G primer, 3 G-UDMA base monomer and titanium dioxide-polymethacrylate composite pigment, bonded strongly to the alumina-blasted cobaltchomium alloy. This opaque resin may be useful to bond fixed prosthodontic composite and metal frameworks.

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To clarify the color of porcelain fused to metal crowns, we examined opaque porcelain baked on a metal base using a color and color difference meter. The following types of materials were used in fabricating the samples:(1) 84.3% Au-Pt-Pd-Ag alloy, (2) 81.9% Pd-Cu-Ga alloy, (3) 77.0% Ni-Cr alloy, (4) Brown opaque porcelains; A₁0, A₂0, A₃0, A₄0, (5) Grey opaque porcelains; C₁O, C₂0, C₃0, C₄0, (6) Red opaque porcelains; D₂0, D₃0 and D₄0. The masking effect on the color of the metal base was examined.
The following results were obtained.
1. The color of the opaque porcelain fused to the metal was affected by all opaque porcelain colors having 0.10-0.20 mm thick opaque porcelain layer. The masking effect on the color of the metal was as follows; In case of light color opaque porcelain, D group colors were the highest, followed by C group colors, with A group colors being the lowest. In case of dark color opaque porcelain, C group colors were highest, followed by A group colors, with D group colors being the lowest. Opaque layers thicker than 0.25 mm were not affected by the opaque porcelain colors.
2. The color of opaque porcelain fused to the metal was affected by all metal colors for 0.10-0.20 mm thick opaque porcelain layers. The masking effect on the color of the metal base was as follows; Au-Pt-Pd-Ag alloy was the highest, followed by Ni-Cr alloy, with PdCu-Ga alloy being the lowest. Opaque layers thicker than 0.25 mm were not affected by the metal colors.

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In order to evaluate the kinematic function and the coordinated movement of articulatory organs, attention was focused on the palatal form in various factors related to pronunciation abilities with complete dentures. After an experimental palatal plate was inserted into 13 natural dentitions ranging from 21 to 24 years old, muscular discharge of tongue muscules, tongue movement and mandibular movement during pronunciation were recorded longitudinally. Data was comparatively evaluated with that before insertion of the experimental palatal plate, and the following conclusions were obtained:
This study has been established that changes in muscular discharge of tongue muscles, tongue movement and mandibular'movement during pronunciation before and after insertion of an experimental palatal plate, are fast in some degree in recovering of kinematic function and the coordinated movement among articulatory organs, comparing with them of before pronunciation.

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Patients having skeletal class III malocclusion are known to exhibit a wide variety of chewing patterns. This situation is believed to be caused by differences in occlusal conditions, the nature of which have not been clarified. I therefore investigated the relationship between their occlusal condition of the molars during lateral excursion and their chewing patterns.
With regard to occlusion, I measured the distance between each occlusal surface of the lower molars and its opposing surface in a lateral occlusal position. Regarding masticatory patterns, I classified chewing strokes of the incisal point into 4 patterns, depending on whether or not the gliding phase was in evidence.
The results were as follows: 1) In cases where gliding movements appeared during chewing strokes, the average of the measured distance on the working side was less than 0.7 mm; 2) even if this condition regarding distance was satisfied, gliding movement did not appear, if occlusal contact occurred on the non-working side.
The results cited above show that disclusion of the working side molars and the tooth contact of the non-working side molars during lateral excursion directly affect the commencement of the gliding phase in chewing strokes.

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This study was intended to investigate the effect of irradiation time, thickness of denture plate and shading on the apparent curing depth of trial visible light curing relining material (PN) in the case of direct irradiation to the mouth. Relining materials already available on the market were used for the experiment. The following results were obtaind:
1. As the irradiation time was extended, the curing depth also increased but not in direct proportion.
2. As the thickness of the resin plate increased, the curing depth decreased. When the thickness was doubled, however, the curing depth was not reduced by half.
3.#6 (Natural Light Pink), #7 (Natural Dark Pink) and #8 (Live Pink) were uneven due to particles and fibers. In these cases, the curing depth tended to be larger.
4. The trial relining material (PN) displayed the most ideal curing depth with regard to irradiation time and changes in the thickness and shading of the resin plates.

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Nitrides used in this experiment are h-BN, A1N and Si₃N₄. The feasibility of using the nitrides was studied as wax pattern coating materials for a Co-Cr alloy in an atmosphere of argon. Wax patterns were painted with the nitride coating material (first investing), and then it was outer-invested with a mixture of gypsum-bonded investment and water (second investing). The temperature of mold was 700°, and the thin specimens were cast with an argon arc vacuum-pressure casting machine in the Co-Cr alloy (composition Co: 63 wt%, Cr: 27, Mo: 5, Bal.: 5; melting point: 1, 380°). Surfaces of cast specimens were investigated with the unaided eye, a scanning electron microscope, a surface roughness analyzer, an X-ray diffractometer and a micro-Vickers hardness tester.
Furthermore, the cast clasp using an h-BN coating material were made and investigated with the unaided eye.
Results were summarized as follows:
1. The nitrides inhibited remarkably a reaction between the cast specimen and the investment.
2. BN had the good effect of separation.
3. The cast surface coated BN had less clinging than uncoated one. This indicated that cleansability and work efficiency were improved.
4. The surface roughness (Rz) of the specimens decreased to 32, 42 and 60% of the control with BN, Si₃N₄ and A1N, respectively.
5. A hardness change of the alloy by casting was the least in the case of using BN.
6. BN also had the effect in fabricating a cast clasp in the clinical form.

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It is essential for denture treatment to prove relationship between occlusal adjustment and pressure transmitted to the supporting tissues. In order to investigate this relationship, the pressure distribution beneath a denture was measured in the process of occlusal adjustment, using the diaphragm pressure sensor and digital processing system. For this purpose, six subjects with edentulous ridges were selected and divided into groups on base of the degree of mandibular resorption. Group I consist of patients with low degree resorption and Group II of ones with high degree.
The conclusions as to the change of pressure distribution by proceeding occlusal adjustment were as follows.
1. Occlusal adjustment led to adequate distribution of pressure beneath a denture.
2. Premature contact had a great influence upon proper distribution of pressure.
3. Group II was more affected on distribution of pressure by premature contact on occlusion than Group I.
It is confirmed that the capacity of supporting the denture was different in each area on supporting tissues and it is important that pressure distribution should be harmonized with each supporting capacity on denture basal seat.

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