An attempt has been made to review a clinical stage of recording the jaw relationship for removable partial dentures. The basic factors for registration of maxillo-mandibular relation have been reviewed from a view point of the functional characteristics of load supporting tissues and mandibular movements by M. Kishi in chapter II. T. Goto has dealed with the role of remaining teeth in the recording the jaw relationship in chapter III. E. Mushimoto has pointed out registration errors of jaw relation with the deviated mandible in molar loss. And E. Nagaoka has presented fundamental date for determination of occlusal plane and vertical dimension using film image information in chapter V. A. Manabe has detailed on possible errors accompanied with clinical procedures during recording the jaw relationship and on measures for avoiding them in chapter VI. Further, the clinical procedures to improve an accuracy of the bite taking and of its representation on an articulator has successfully been shown by T. Miyata in chapter VII. Fujii wrote general introduction and summary.

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Recently some electronic parts have been applied to dentures in many oral researches. However, undesirable characteristics of electronic parts will be influenced by temperature.Therefore, it is very important to find stable thermal portions for placing these parts.The objective of this study was to measure the thermal changes on the polished surfaces of complete dentures during mouth movement and to find stable thermal portions.In this experiment, eight thermal sensors were set on the upper and lower polished surfaces of complete dentures for every five complete denture wearers.A hot tea, cold water, hot rice and flaked ice were used as test foods, and thermal changes were measured while ingesting these test foods.
The following conclusions were obtained:
1.The thermal changes on the buccal polished surfaces of upper and lower dentures were small.
2.The thermal changes on the palatal polished surfaces of upper dentures were significantly larger than those of lingual surfaces of the lower dentures.And the thermal changes on the lingual polished surfaces of lower dentures was small, especially on the non-working side.
3.These findings indicated that both buccal portions of upper and lower dentures and lingual portions of the lower denture on the non-working side were more suitable for installing electronic parts.

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We made a Co-Cr alloy containing 0-10% titanium for Konus-Telescope Denture. The results of physical properties were published in part 1.The purpose of this study was to investigate the porcelain bonding strength, the adaptability, and the castability of these alloys.
The results were as follows: The porcelain bonding strength became higher as the contained titanium percentage was increased.The alloy containing 6% titanium showed maximum porcelain bonding strength, the alloy containing 2% showed the second highest porcelain bonding strength. But there was no significant difference between alloys containing 2% titanium and 6% titanium concerning the porcelain bonding strength.Vertical displacement enlarged as the contained titanium percentage was increased after the work process.Castability was excellent as the contained titanium percentage was increased.Considering these results, the Co-Cr alloy containing 2% titanium alloy was suitable for porcelain bonding alloy.

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It has been observed that the tonic discharge disappears to some extent immediately preceding the rapid voluntary movements.This phenomenon, premotion silent period, has been considered the learned, rather than automatic, motor response.The present study was designed to reveal the premotion silent period at ballistic voluntary jaw movements. While 7 healthy male subjects (25-27 yr) made slight voluntary clenching and maintained it steadily, they were asked to respond with the maximum voluntary clenching as rapid as possible to acoustic stimulus. The myoelectric signals from masseter muscles, temporal muscles, and anterior bellies of digastric muscles were simultaneously recorded.
The results obtained were as follows:
1.In five out of the seven subjects, the premotion silent period was observed in the masseter muscle.The frequency of the premotion silent period for the seven subjects was 30%.
2.The premotion silent period was also recorded for temporal muscles.
3.When the silence occurred prior to the distinct bursts of the masseter muscle, no bursts was found of the antagonist, i.e.anterior belly of digastric muscle.This finding suggested premotion silent period was not a reciprocal a inhibition.

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The purpose of this study was to investigate the retentive force distribution of the upper overlay denture with magnetic attachments.The magnetic attachment used in this study consisted of a magnetic assembly and a magnetizable metal commonly refered to as a keeper.The keepers were attached to the bilateral canine and/or second molar regions on the upper edentulous model, while magnetic assemblys were attached to the upper denture which was made of an acrylic resin.The retentive force was measured by pulling at eight locations on the denture vertically with a tensile testing machine.
The results were as follows:
1.The retentive force was greater at locations near the magnetic attachments and decreased at locations further away from magnetic attachments.
2.In the case with two magnetic attachments, the retentive force distribution was more influenced by the arrangement of attachments than other cases.
3.The denture with three or four attachments showed stable retentive force distribution.
4.The maximum retentive force was smaller than the total attractive force, which was 40-70%.

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The influence of post-curing on the color stability of composite resin was investigated in vitro with the use of five types of light-activated veneering materials.Specimens were cured by means of a high-intensity light source followed by heating at 100°C for 60 minutes.Prepared specimens were immersed in water for up to 180 days and the color change of light-cured and heated materials was less than that of unheated control materials during the observation period from 60 to 180 days.On the basis of color analysing of veneering materials, it may be concluded that post-curing by heating is effective for enhancing the color stability of light-cured composite resins.

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he adaptability of superplastic titanium alloy plate dentures constructed by controlled polymerization system, that is the DS system, was investigated in comparison with that constructed by autopolymerization and heat polymerization. Heat polymerization was carried out in a water bath at 70°C for 24 hours.
The superplastic titanium alloy plate before and after molding had a bending elastic modulus of 14, 200 kgf/mm² and 17, 000 kgf/mm², respectively. The plate had a Knoop hardness number of about 374 across the entire cross-section. And the hardness of the plate before and after molding was approximately equal. The discrepancy of the dentures constructed by the DS system for stone cast was 0.127 mm at the denture border. The 0.127mm discrepancy was equal to one-half or one-fourth the discrepancy of the dentures constructed by other polymerization methods. Compared with other polymerization methods for adaptability, the DS system was advantageous.
Although the discrepancy after the unilateral loading test increased, the DS system produced the smallest discrepancy across the entire section among these ploymerization methods. The discrepancy of the dentures constructed by other polymerization methods was about twice that of the dentures before the unilateral loading test.

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We discussed the relation between the behavior of the reaction layer and the concentration of the colloidal silica solution as the mixing liquid, on the surface layer of the pure titanium crowns that was produced by using the phosphate-bonded thermal expansion inhibited, investment, and compared it with the phosphate-bonded investments on the market as well.
The results were as follows:
1.There was a hardened layer in the surface layer of cast crowns, and the hardness showed the greatest value in the condition of 40% colloidal silica concentration.
2.In the surface layers of metallic textures, there were chill layer and columnar structure layer in that order from surface.
3.There was a poor Tilayer on the surface. The thickness of the layer increased accordingly to the increase in colloidal silica concentration.
4.In the poor Ti layer, there were O, Si and P.
5.Si and P were observed correspondingly in the cellular boundary in a string form.
6.Not only the refractory material but also the concentration of colloidal silica solution as the mixing liquid influenced the behavior of the reaction layer.

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Since bioactive glass has been known as a biomaterial that can bind directly with bone by forming a calcium-phosphate and silica-rich layer on its surface, it is necessary to ascertain the mechanism and biological characteristics involved in the surface layer of bioactive glass.Thus, to approach this matter, the author investigated the surface layer of bioactive glassin vivoby implanting them into the abdominal cavities of mice for 21 days, and compared them to other experimental materials such as hydroxyapatite and titanium.The bioactive glass surface layer was confirmed by an energy-dispersive X-ray analysis, and the effect of these biomaterials on immunocytes were also evaluated.
Results showed lipopolysaccharide (LPS)-induced³H-thymidine uptake by spleen cells and nitric oxide (NO) production by mice peritoneal macrophages to be reduced by the intact bioactive glass, and LPS-induced interleukin 1α(IL-1α) production by human peripheral mononuclear cells to be enhanced.However, after formation of a surface layer on the bioactive glass, hardly any effect in terms of LPS-induced 3H-thymidine uptake, production of NO, and IL-1α.was observed, as well as with the other biomaterials.
Studies suggest that the surface layer of bioactive glass formed in vivo had very little effect on immunocytes, and that these results were similar to hydroxyapatite and titanium which are consid ered to be biocompatible.

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n removable prosthetic dentistry, the interrelations among anatomical landmarks, which can give significant information for diagnosis, can be observed on an orthopantomogram.
This study was to investigate how to use an orthopantomogram in prosthetic therapy.
Veraview (J.Morita Corp., Tokyo) was used as panoramic equipment.The removable hand-made ear-rods that attach to the plates supporting the temples, were used to ensure correct posture of the head, with the forehead rest.
First, the effects of posture of the head in the equipment on the image were examined experimen-tally by using dry skulls, one with dentulous ridges and the other with edentulous ridges.Theposture depends on the positions and angle of the antero-posterior direction.
Secondly, 63 orthopantomograms of students in our dental school were traced.The interrelations among certain anatomical landmarks on those traces were analyzed linearly and angularly.
Finally, the measurements from the orthopantomograms of the students were used to make a diagnosis of the occlusal plane and vertical dimension for old and new dentures of an edentulous patient.
This study indicates that the analyzing method, on the traces of orthopantomograms, was useful for the diagnosis of the occlusal plane and vertical dimension in edentulous patients.

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This study investigates the influences on tapping points when the articulating paper and holder are inserted in the human mouth unilaterally and bilaterally.
The subjects with no abnormalities in the stomatognathic system were selected for this study.
Mandibular movement was measured with Mandibular Kinesiograph (Myo-tronics, K 6), and tapping points were calculated from the beginning of the mandibular movements by a signal processor (NEC San-ei, 7 T 17) and statistically analyzed with a personal computer (NEC, PC-9801 RX). The tapping points in four subjects were scarcely displaced, but the tapping points in the other six subjects were significantly displaced. The direction of this displacement was contralateral and anterior in the unilateral condition and more anterior in the bilateral condition.

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To assess the clinical characteristics of occlusal treatment following EMG biofeedback occlusal analysis in craniomandibular disorders (CMD), the mode of occlusal treatment and the results were analyzed in about 400 CMD patients treated at our clinic. Of the results of treatment, 70% of the patients were completely relieved of their CMD symptoms by occlusal treatments, primarily including occlusal adjustment (OA), occlusal splint therapy (SP) and insertion of treatment dentures (TD). These treatments were continued in 18% of the patients at the time of gathering the data and the rest ceased their treatments. Occlusal adjustment (OA) of the occlusal interferences detected by the biofeedback analysis were indicated in 50.4% of the completely cured patients. Occlusal splint therapy (SP) were performed in 22.6% of them and treatment denture (TD) were inserted in 13.6% of them. OA were observed in relatively younger patients at higher rate levels, while SP and TD treatments were observed more frequently for elderly patients. These findings clearly show that the use of biofeebdack occlusal analysis is effective for the diagnosis of various occlusal problems causing CMD. The difference of the indications of the mode of treatment suggests that the occlusal problems causing CMD differ according to their age level.

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The aim of this study was to elucidate the curing pattern of the clinical signs/symptoms in craniomandibular disorders (CMD) throughout the treatment period. 291 patients, who used CMD in this study, were completely relieved of their signs/symptoms at the end of the treatment process. The treatment process included occlusal adjustments, occlusal splint therapy and treatment dentures diagnosed with the use of biofeedback occlusal analysis.The patients were treated at 2-week intervals and the symptoms were examined and recorded. The average treatment times needed for complete cure of CMD was 7.00±5.02. The treatment period for each sign/symptom was calculated based on the total number of treatments for each patient. These were then compared and ranked statistically. First, the sequence of the signs/symptoms relieved were as follows. Tenderness on trapezius, posterior temporal, and occipital muscle disappeared significantly (p<0.01, t-test), and second spontaneous pain, chewing pain, and tenderness on anterior temporal muscle. Tenderness on lateral pterygoid, deep masseter, sternocleidmastoid muscle, TMJ, medial pterygoid, and superficial masseter muscle disappeared in this order. Then opening pain, TMJ noise and tenderness of posterior digastric were relieved (p<0.05). Lastly limited opening was relieved later (p<0.05) than all other symptoms. These findings clearly indicate that the cure of clinical signs/symptoms of CMD in the process of occlusal treatment would definitely have a pattern.

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To clarify the mechanism controlling human mandibular position as a function of lateral inclination of the head, electromyographic investigations of the muscle activities of the inferior head of the lateral pterygoid muscle (Lpt) were carried out while holding different postures with respect to the frontal plane.
EMG recordings were taken at the Lpt, together with the posterior part of the temporal muscle (Tp) and the anterior belly of the digastric muscle (Dig).EMG, incisal movements, and head movements were recorded simultaneously in 15 normal subjects.
When the head tilted to the side, Lpt muscle activities on the side of head tilt and Tp muscle activities on the side contralateral to the tilt increased, and the lower jaw was displaced towards the tilt.These reactions occurred when the head leaned left or right.However, these did not occur when the neck was flexed.These results indicate that reflex muscle activities are antigravity reactions and control the displaced condyle.

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This study compared the molecular structures, densities, tensile strength, tear strength, hardness, abrasion resistance, wetting, and shock energy absorption of polyolefin polymers with those of Erukoflex (EVA), poly (ethylene-vinyl acetate) copolymer in order to determine the suitability of these new materials for use in custom-made mouth protectors. EVA was used as a control.
The results were as follows:
1. IR spectra of the molecular structures of Molteno soft (MS), Molteno regular (MR), and Molteno hard (MH) identified as ethylene-propylene thermoplastic elastomers.
2. The densities of MS, MR, and MH were measured to be 0.868, 0.875, and 0.885 g/cm³ respectively. All were lower than that of EVA.
3. The tensile strength, tear strength, hardness, and abrasion resistance were largest in MH, followed by MR and then MS. EVA was comparable to MR with regard to these physical properties.
4. These 3 materials had contact angles to water of 89-97 degrees. The contact angle of EVA was 94.6 degrees.
5. The shock energy absorption was largest in MS, followed by MR and then MH.

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Soft lining materials for denture bases are sometimes considered advantageous for patients who are capable of delivering a relatively heavy occlusal load to unfavourable denture bearing tissues. These materials have been recommended to prevent excessive pressure on residual alveolar ridges and to provide a more uniform load distribution by absorbing the “mechanical shock” caused by masticatory forces.
There are, however, many defects appearing in long-term use in clinics such as color change, degradation, surface roughness, lack of resiliency, and peeling-off from acrylic resin.
The purpose of this paper is to discuss the findings of a pilot investigation of the physical and mechanical properties of some soft lining materials in order to analyze their color change and degradation.
The results were obtained as follows:
1. It seemed that the properties of tensile stress, percent elongation, tensile strength, tear strength, 25% low tensile stress and Durometer A hardness were useful in characterizing the performance characteristics in relation to the color change of the soft lining materials.
2. There was considerable variation in the physical and mechanical properties of the soft lining materials examined in this study.

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The present study was designed for preestimating the thickness of white silicone film inside the denture base by means of a multiple regression formula induced by multiple regression analysis of multidimensional measurement spectra which was obtained by reflected light spectral analysis.
The multiple regression formula determined from experimental resin plates (1-4.5 mm thick and 0.25 mm interval) in 3 kinds of color tones (S-2, S-3, S-4) was applied to the actual denture base in order to examine the accuracy of the preestimate.The difference (residual) between the actual measurement and regression preestimate proved to be small in each case.Therefore, the present method in combination with reflected light spectral analysis and multiple regression analysis proved to be superior to the various kinds of conventional methods in accuracy, time required and simplicity, suggesting its possible clinical application.

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The present study was to investigate the effect of continuous mastication with the nonhabitual chewing side on mastication function, concerning the subject's groups (G-and C-groups) were classified by mastication pattern.
The stability and effect on the study of mastication with the non-habitual chewing side daily increased, especially in G-group.
As a result of a canonical correlation analysis made between parameters on the chewing cycle and parameters on the masticatory muscle activities, the first canonical correlation coefficient with the non-habitual chewing side daily increased.
In these circumstances, the possibility of the first canonical correlation coefficient becoming and index to skill of mastication was suggested.

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During cementation of a restoration in the oral cavity, oral fluid easily touches the luting media before setting. The purpose of this study was to examine the effect of water immersion time on luting cement, especially during the early stage of setting. A zinc phosphate cement, a polycarboxylate cement and a glass ionomer cement were selected. Molds filled With the specimens were immersed in distilled water 1 min. after mixing, 3 min. after mixing, immediately after setting, and 60 min. after mixing. Then twenty-four hours after mixing, these specimens were embedded in an epoxy resin and were cut longitudinally. The Micro Vickers Hardness of the specimens were measured from 100 μm to 1, 000 μm under the immersed surface with a microhardness test machine.
The results were as follows:
1. The outer part of every cement specimen tested in this study showed an increase of hardness according to the delay of water immersion time.
2. The effect of water immersion time on the glass ionomer cement was greater than that of the zinc phosphate cement, and that of the polycarboxylate cement was the weakest.
3. These results emphasize the importance of moistureproofing during cementation.

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The purpose of this study was to investigate the properties of a new glass-ceramic material named CASMIC.
The following results were obtained:
1. The main precipitated crystals of CASMIC after heat treatment are apatite and magnesium titanate.The size of these crystals is about 0.1 micrometer.
2. The bending strength of CASMIC and DICOR after heat treatment is 160 MPa, 150 MPa, respectively.The Vickers hardness number of CASMIC is 748.This value is twice that of human enamel.
3. Fracture toughness of CASMIC is 1.83 NMm^1/2. This value is higher than that of the commercial dental porcelain.
4. The density of CASMIC after heat treatment is 3.4g/cm² similar to that of enamel.
5. The thermal diffusivity and thermal conductivity of CASMIC was 5.9×10^-3cm²/sec and 3.2w/m/k, respectively.
6. Total light transmittance of CASMIC and DICOR after heat treatments 18.3% and 60.4%, respectively. The value of CASMIC is similar to commercial body porcelain. The value of DICOR is higher than that of commercial enamel porcelain.
These results show that this material has many favorable properties as new glass-ceramics for the restorative materials.

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ree different experimental partial palatal bars with connector apparatus at different setting positions (hereinafter referred to as anterior palatal bar, middle palatal bar and posterior palatal bar) were set in patients with healthy dentulous mandibles and duration and amount of EMG activity of facial muscles prior to speech were recorded over time, and the results were compared with the values before setting and also between the experimental partial palatal bars.The conclusion was as follows.:
1.In middle and anterior palatal bars, the sound under study showed significant elongation and increase immediately after setting on bilateral muscles, and the values reached a constant level on the 3 rd day and after.
2.In the posterior palatal bar, almost all sounds under study showed significant elongation and increase immediately after the setting on bilateral muscles.The EMG duration of the oral sphincter reached a constant level on the 3rd day and after, EMG activity on the 7th day and after, and inferior labial quadrate muscle on the 14th day and after.
From the above results, this suggests that, in preparing partial denture by taking articulatory function of lips into account, the middle palatal bar and the anterior palatal bar are more advantageous to be used as connector apparatus.

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In the case of complete denture, the master cast should represent thecontour of the oral mucosal surface, also taking account of the basal soft tissue with regard to supporting ability. In this study, impressions were taken of a simulation model of the mandibular edentulous ridge, using silicone rubber (SIL), polysulfide rubber (RUB) and alginate (ALG) as impression materials and impression tray with stoppers. The effects of the type of impression material, seating speed and holding pressure of the impression tray on the contour of the master cast were investigated in terms of profiles and displacement. The results were as follows:
As described above, of these three factors which influence the form of the working model of the mandibular edentulous ridge, (i.e. the influence of the choice of impression material on the impression pressure, of the tray seating speed and the holding pressure), during impression-taking, the most influential is the holding pressure of the tray. This suggests that full consideration must be given to the supporting ability of the under lying tissues when taking impressions from patients with a mandibular edentulous ridge.

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This study was designed to observe the initial healing of alveolar ridge bone defects of animals around the implant using a membrane technique. In control-I and -2, the defects were filled with the connective tissue 10 days after operation. So we could not expect bone formation in this site. However, this study indicated that bone formation would be ensured by maintaining the space between periosteum and bone using a membrane technique. The osteogenic mesenchymal cells would become osteoblasts in the space and produce bone tissue.

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The distribution of occlusal support of 366 aged patients of over 70 years was surveyed and analyzed in this study. Their masticatory abilities were also evaluated by the questionnaire on the masticatory aspects of 20 kinds of foods, and their maximum occlusal forces were measured with the pressure sensitive foil. The relations among masticatory ability, maximum occlusal forces and the distribution of occlusal support were analyzed.
The results were as follows.
1. 52.8% of the upper and lower dentulous patients had less than 5 occlusal tooth contacts.
2. Posterior tooth contacts were less than anterior ones, and even in posterior areas, occlusal contacts tended to be less from the second molar to the first premolar.
3. 61.2% of the upper and lower dentulous patients had no occlusal support or only unilateral occlusal support. It is evident that occlusal support is extremely ill-conditioned in elderly patients.
4. It was found that if the aged have more occlusal tooth contacts and wider occlusal support areas, they would show better masticatory ability and greater maximum occlusal forces.
5. In thier initial visits to our clinic they had poor occlusal support with their dentures.
6. It is suggested that occlusal tooth contacts and occlusal support areas should be important for maintaining a healthy oral function in elderly people.

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The purpose of this study was to investigate the relationship between lips and upper anterior teeth during oral functions. This relationship will help us understand the role of the lip support in oral functions. 96 subjects with normal occlusion and 36 edentulous patients were selected. Seven points on the lips were set for tracking and three points on the labial surfaces of the central incisors and the canines as marks. They were measured in three-dimensional coordinates referred by Camper's plane. And they were measured under thrusting of the lips, pulling the mouth corners backward and closing of the lips intentionally. The edentulous patients were tested with and without denture. Each data was transferred to the one coordinates and compared to each other.
The findings were as follows:
1. The movements of median points on the lips showed great variation.
2. The mouth corners moved similarly in their direction and moved on one plane.

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