Recently, we experienced the dental treatment of the pacemaker-implanted patients suffered from chronic cardiac insufficiency (CTR=77.0% and 59.0%). In this study, the influence of dental chair position on the general condition was analyzed by monitoring capnomonitor. In addition to cardiovascular management, respiratory management was effective to evaluate the general condition of patients in dental treatment. In the supine position, the capnogram indicated two or three peaks in the expiration flat phase, however normal capnogram was seen in the upright chair position. Further, lower value of transcutaneous arterial oxygen saturation (SpO₂) was seen in the supine position. Since agitation in the capnogram emerged immediately after positioning, the cause of this adventitious sign was thought to be the suppression of respiration in the supine position. This study suggested that forcing patients with cardiac insufficiency into the supine position might increase the risk of adventitious diseases in dental treatment.

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Polymethylmethacrylate (PMMA) is a component of resin teeth, which are generally depolymerized at a temperature of 220-240°C. If resin teeth are used in Polysulfone (PSF) dentures, thermal anamnesis may occur, causing artificial teeth to become worse, when producing dentures.
Therefore, what thermodynamics cause thermal anamnesis of PSF dentures were analyzed in the compressive molding method to determine the influence on resin teeth.
The results were as follows:
PSF dentures use resin teeth and high wear resistant plastic teeth. These teeth are not influenced by thermal depolymerization. The retention strength of artificial teeth weakens during laboratorial operation, and even if dry volatile components are included, their weight decreases slightly. Therefore, artificial teeth should be dried at 130°C after investment and wax removal in a dry oven. Each value will be more than 18.1 kgf, so it will be sufficiently durable for clinical use, taking the results of Okuno et al. and Kimura et al. into consideration.
As a result of the analysis of temperature change between the retention surface of artificial teeth and denture base resin in the finite element method in both cases 1 and 2, the temperature of the projecting part of an artificial tooth shows a temperature of 240°C or more just after completion, however, shortly afterwards, it shows a temperature of 220°C, proving that thermal depolymerization hardly occurs in an artifical tooth, if real thermal capacity, thermal energy, etc. are taken into consideration.

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The dimensional changes of the denture base of mandibular removable partial denture (Kennedy class I modification 1) following polymerization were examined. The removable partial dentures were made from three different denture base resins (heat-cured, pour-type, microwave-cured). The dimensional changes of the denture base were measured by using the three-dimensional measurement system over a period of 4 weeks. Immediately after deflasking, the heat-cured dentures showed linear shrinkage of 0.37% to 0.59%. The pour-type dentures showed linear shrinkage of 0.16% to 0.30%, but the lingual flange showed linear expansion of 0.08%. The microwave-cured dentures showed linear shrinkage of 0.30% to 0.68%. After deflasking up to 4 weeks, the heat-cured and the microwave-cured dentures gradually expanded, but these dimensions did not reach the original model size. The pour-type dentures gradually expanded, and their dimensions reached the original model size, but the lingual flange showed linear expansion of 0.65%.

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In our study using rotational panoramic radiography for quantitative analysis of edentulous patients, a new mandibular positioner was developed and reformed to measure mandibular corpus height in dried human mandibles.
The purpose of this study was to examine the mandibular bone height in edentulous patients.
Six edentulous patients were chosen, and each subject was set on the mandibular positioner for rotational panoramic radiography. The mandibular plane of the patient was positioned horizontally with the mandibular positioner and eight metal tubes were vertically placed into the occlusal rim at the crest of the mandibular corpus.
The mandibular corpus height of six patients were estimated by calculating the magnification rate of metal tubes obtained from the rotational panoramic radiogram.
In this study, it was found that calculation of edentulous mandibular corpus height was clinically possible by using the metal tubes and the mandibular positioner.

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It was attempted to apply barrel finishing to improve the surface texture of the basal surface of the complete denture. The effect of barrel finishing on the denture base resin of rough surface should be confirmed to understand the alteration of the basal surface of complete denture after barrel finishing, because it is corrugated. The denture base resin samples with standardized corrugated surface were made using a metal mold, then each sample was divided into halves. One of the halves was barrel finished following the manufacturer's instruction after masking the datum plane, whereas the other one was used as a control without finishing. Both samples were observed under the reading microscope, and the distances between the base line and the top of each corrugation or the bottom of each corrugation were measured. Observation under the scanning electron microscope was also made. The results were as follows:
1. The scanning electron microscopic observations showed that the top of the corrugation was obviously made round and smooth by barrel finishing, and that the bottom of the corrugation was also made smooth but it was less smooth than the top of the corrugation.
2. The cutting depth of the denture base resin was 218.13μm at the top and 3.53μm at the bottom of the corrugation.
These findings suggest that there is no problem after barrel finishing of the basal surface of complete dentures even if attention was paid to the height of the bead established for the posterior palatal seal.

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This study was conducted on the occlusal contacts during physical exercise.
The experiment was carried out to examine the clenching strength on the occlusal contact area and occlusal force when one grips by using a Dental Prescale System. The subjects were 9 males.
The results were as follows:
1. Majority of subjects showed the maximum clenching strength on the occlusal contact area and occlusal force.
2. Some who clenched eccentrically, as for jaw relation, and clenched unilaterally to the centric occlusion were observed.
3. Some who clenched stronger than the maximum clenching strength and the rest who clenched weaker than maximum clenching strength were observed.

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The present study was made to elucidate the training effect of examiner's palpation force on the evaluation of pressure pain examination. Using our newly-developed simulator, right and left second fingers' palpation forces in 29 dental students were determined by giving them no special indication (P 1) and making them reproduce the forces of 1, 500gf/cm²after making them practice the latter by monitor (P 2).
The results were as follows:
1. The difference of palpation force in P 1 was great compared with that in P 2.
2. Palpation force in P 1 and P 2 showed no significant laterality.
3. Palpation force after training tended to be near the appropriate palpation force.
The above results suggest that training for fingers' palpation force may be effective for formation of quantitative kinesthesis and elevating the reliability of the evaluation of pressure pain examination.

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In order to develop a measurement system for the additional load by contacting the basal surface of the pontic, polyvinylidene fluoride film (PVDF) was used to investigate its usefulness.
The following four parameters correlated with additional loads:
(1) maximum of positive output voltage, (2) maximum of negative output voltage, (3) first area surrounded with non-output line and output voltage line, and (4) entire area surrounded by non-output line and output voltage line.
Additional loads were computed by these parameters.
The result indicates that PVDF is useful for measuring the load added by contacting the basal surface of the pontic.

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Since titanium shows high adhesive force to a high polymer by way of oxide film covering its surface, its usefulness to the resin veneered crown is expected. In the present study, emphasis was placed on “wettability, ” which is closely related to the adhesion between titanium and resin, and-with the aim of clarifying the causes of surface properties, which affect wettability of the titanium surface-the surface roughness of various treated surfaces, as well as contact angles of the primer and distilled water to such surfaces, were investigated. The results were as follows:
1. No change was observed between surface roughness after sandblasting for 15sec/cm² (SB 15) and surface roughness obtained by extending the sandblasting time to SB 30, SB 45 and SB 60.
2. As a result of giving atmospherically-heated oxidation treatment of 600°C-60 min to titanium surfaces of SB 45 and SB 60, its surface roughness exhibited a greater increase than that of the non-heat-treated or “400°C-60 min”-treated titanium surface.
3. Contact angle of the primer to the titanium surface was 0°C in the cases of all titanium suface.
4. As a result of giving the atmospherically-heated oxidation treatments of 600°C-60 min to the titanium surfaces of SB 45 and SB 60, each contact angle of distilled water to these surfaces was 25°50′, which is the minimum value.

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All-ceramic crowns are the most esthetic, because they transmit light similarly to natural teeth. However, because of the translucency of all-ceramic crowns, the color of the abutment tooth can affect the color of the final crowns.
The aim of this study was to investigate the influences of the color of the abutment tooth on all-ceramic crowns.
Ceramic disc specimens (In-Ceram, Hi-Ceram, Optec and G-cera II), metal disc abutment specimens (type IV gold and gold-silver-palladium alloy) and porcelain disc abutment specimens (A 1 and A 4) were used for the study. The color of ceramic specimens was measured with a small area colorimeter by translucent and reflectant methods and evaluated by the CIE L*a*b* color system.
The results were as follows:
1. All ceramic systems with an aluminous core have low translucency, so the color of the abutment tooth does not have to be considered.
2. All ceramic systems with masking porcelain have high reflectance, so the light reflectance have to be considered.
3. All ceramic systems with high translucency have to be considered due to the effect of the color of the abutment tooth.

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Electromyograms (EMG) were examined during tapping movements to determine the effect of local pressure on mucosa underlying free-end saddle partial dentures in 6 denture wearers. EMG of the bilateral anterior temporal muscles (Ta) and masseter muscles (Mm) were recorded together with Mandibular Kinesiograph motions. Four plate types of two different diameters and thicknesses were fastened to the basal sheet of the denture to apply pressure. The degree of local pressure was at a subtle sensation level.
There were significant variations in EMG time parameters and integrated EMG among the experimental conditions. Cycle time had no change, and EMG burst duration was extended under the experimental condition, so that the burst interval was shortened. The change of duration was influenced of burst duration preceding tooth contact. The coefficient of variance for EMG time parameters was higher than that of the control under the experimental condition. EMG activity outlasting tooth contact of Mm and Ta decreased. The ratio of Ta activity of before tooth contact to that of the control significantly changed, contralateral activity was increased and ipsilateral activity was inhibited.
The present data suggested that a compatibility of the denture base and the mucosa was clinically important.

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The mechanism and movement of Gysi Simplex OU articulator was clarified in our previous study. This articulator has optional incisal guide tables with lateral wings.
The movements of the articulator with four different angles of lateral wings were measured with Kyushu University 3-D Movement Analyzing System. The results were as follows:
1. The rotational points existed when the incisal guide tables with the lateral wings were used.
2. Lateral rotational axes were constructed by joining three rotational points at three different heights.
3. As the incisal inclination became steeper, the rotational point was located more anterolaterally at the height of the condyle guide pin, and was located more anteromedially at the height of the occlusal plane and incisal guide pin.
4. As the incisal inclination became steeper, the axes changed from convergent axes to divergent axes.

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A study was made on the stress-bearing features of the denture basal seat with changes in the balance and non-masticatory articulation under right-side occlusion. The model for each of right-side occlusion, right rubber-molar occlusion, and right-resin molar occlusion was established. The distributions of stress-bearing in the lower complete denture basal seat were compared. The results were as follows:
1. Right-side occlusion (right) Stress borne by alveolar bone was substantially lower than that borne by alveolar mucosa except in the central incisor.
Stress rose significantly on the working side of the ridge, border, buccal, lingual, and retromolar pads, and fell significantly on the balancing side.
2. Right rubber-molar occlusion (rubber) Stress borne by alveolar bone was substantially lower than that borne by alveolar mucosa except in the central incisor.
Stress on the masticatory side of the ridge, border, buccal, lingual, and retromolar pads was significantly higher than in cases of centric and right occlusions.
3. Right resin-molar occlusion (resin) Stress borne by alveolar bone was substantially lower than that borne by alveolar mucosa except in the central incisor.
Stress on the masticatory side of the ridge, border, buccal, lingual, and retromolar pads was significantly higher than in cases of centric, right and rubber occlusions. Conversely, stress on the non-masticatory side was significantly lower. Negative stress-bearing was found on alveolar mucosa on the non-masticatory side. No stress-bearing was noted on alveolar bone.

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To elucidate the influence of craniofacial form and periodontal mechanoreceptor on EMG activity, the magnitude of bite force during vertical clenching and EMG activity of Masticatory muscles was compared under anesthetic conditions. Based on the results of our study, we concluded the following:
The unit EMG activity was the same on the anterior temporalis and posterior temporalis regardless of the specified range and the anesthetic conditions. Unit EMG activity was almost on the same level regardless of anesthetic conditions at 100, 75 and 50%MC on masseter muscle and at 100 and 75%MC on the lateral pterygoid. Significant difference (p<0.05) was noted in unit EMG between non-anesthesia or lower anesthesia and upper/lower anesthesia at 25%MC on the masseter muscle and lateral pterygoid. Further, significant difference was noted between non-anesthesia or lower anesthesia and upper/lower anesthesia at 50%MC in the anchor region on the lateral pterygoid.
In non-anesthesia and upper jaw anesthesia, significant correlation (α=0.05) was noted in the specified range of Ar-Go-Me, MM-SN, SN-OP, MP-OP, Ar-Go, and CCUAG-KR on the anterior temporalis, in MM-OP, SN-OP and Ar-Go on the masseter muscle, in SN-OP on the posterior temporalis, and MM-OP, SN-OP and MP-OP on the lateral pterygoid.
In lower anesthesia and upper/lower anesthesia, significant correlation was noted in almost the same measurement items as those of non-anesthesia and upper anesthesia on each of the muscles studied. Further, when compared with non-anesthesia and upper anesthesia, significant correlation was found at 100%MC in Ar-Go and 75%MC in CC⊥AG-KR on the anterior temporalis, and 50% and 25%MC in SN-OP in the masseter muscle, while there was no significant correlation in Ar-Go-Me and MP-OP on the anterior temporalis.

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This study was carried out to investigate the effect of the anterior guide angle on electromyographic (EMG) activities in the inferior head of the lateral pterygoid muscle (Lpt) and the anterior belly of the digastric muscle (Dig).
EMG activity, incisal movement and condylar movement were recorded and analyzed while changing anterior guide angle in five subjects with normal jaw function.
Increasing the angle significantly changed the EMG activities of Lpt and Dig, and the pattern of muscle activities differed. The pattern of change in translation of condylar movement was similar to EMG activity of Lpt. The pattern of changes in inclination of incisal movement and degree of condylar rotation were similar to EMG activity of Dig. Significant correlation was found between EMG activity of Lpt and translation of condylar movement, and between EMG activity of Dig and inclination of incisal movement and degree of condylar rotation.
It was found that protrusive movement could be performed smoothly by coordinating Lpt and Dig to accomodate changes in the anterior guide angle.

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The purpose of this study was to investigate stress distribution in bone around bone-bonded and bone-adapted titanium cylindrical implants with various thread angles using 2-dimensional finite element analysis. In the bone-adapted model, the slip element was used at the interface between the bone and implant. The results were as follows:
1. In bone-bonded titanium implants, stress concentration was observed in compact bone around the neck of the implant. Various thread angles scarcely affected stress distribution and stress value in bone around the implant.
2. In bone-adapted titanium implants, stress concentration was observed widely in cancellous bone around the thread ridge and bottom of the implant and in cortical bone around the neck of the implant. The stress value in bone reduced. These facts indicated that thread design was effective on stress reduction in bone around the implant. Especially, a 30-degree thread angle reduced the stress value utmost.

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This study was carried out to evaluate the relationship between frontal dentoskeletal form and lateralized masticatory index or bite force magnitude and direction.
Eighteen subjects, belonging to the normal face group were studied, and the frontal dentoskeletal form was analyzed with posteroanterior cephalograms. The subjects were divided into left deviation and right deviation groups, and mechanisms of jaw functions were analyzed in terms of lateralized masticatory index and bite force angulation in the horizontal plane during vertical clenching. The magnitude of bite force was divided into 4 steps, and the results were as follows:
1. Lateralized masticatory index showed the chewing side to be the same as the deviation side of the frontal dentoskeletal form.
A significant correlation was found between two groups for angle analysis item ∠Um-Um′ of frontal dentoskeletal form and right deviation group for distance analysis item Me-ML.
2. Bite force angulation in the horizontal plane showed the same phenomenon with frontal dentoskeletal form and lateralized masticatory index.
In the correlation of frontal dentoskeletal form and lateralized masticatory index and direction of bite force, significant correlation was noted in two groups of frontal dentoskeletal form of UUm-Um′, UCG-Me and Me-ML at 25% MC with lateralized masticatory index ∠(Zyg-AG)-(Zyg′-AG′) at 25% MC and 50% MC, as well as the left diviation group of ∠(Zyg-AG)-(Zyg′-AG′) at 75% MC with lateralized masticatory index and the right deviation group of ∠CG-Me at 50% MC.

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The purpose of the present investigation was to observe the vertical motion of tongue during mastication using serial ultrasonography. Observation was made on 6 males with an average age of 28.7 with no evidence of neurological disorder. Real-time M-mode ultrasonic observation of the tongue movement during mastication was carried out in the median sagittal plane of the mandible.
The results were as follows:
1. The tongue surface in an ultrasonography M-mode image was continuously recorded without fixed contrivance of the transducer using the operator's finger and holder, because the transducer is small and light.
2. The vertical motion of the tongue was shown in two stages, the sorting out and the bolus formation stages.
3. No difference of tongue position was shown at rest and after swallowing within one individual. The significant differences of the tongue position and movement in subject-factor were analyzed, however, there was no food factor.
4. The tongue movements were slight and slow, when hardness, cohesiveness, gumminess and adhesiveness of the foods texture were high or fracturability of the texture were low.

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The purpose of this study was to clarify how components of biomaterials affect primary calcification of rat bone marrow stromal cells. In this experiment, rat bone marrow stromal cells were cultured on pure titanium and bioactive glass, and each was periodically observed under scanning electron microscopy. Electron probe X-ray microanalysis was also used to analyze the elements, and the DNA content and alkaline phosphatase activity were also measured.
Early stages of rat bone marrow stromal cells tended to indicate faster signs of proliferation and differentiation when cultured on bioactive glass than on pure titanium. Furthermore, it also became evident that calcification began at an early period.
These results suggested that the calcium and phosphate ions from the bioactive glass surface and reactive layer affect the calcification process of rat bone marrow stromal cells.

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The purpose of this study was to examine the relationship between jaw position and masticatory muscle activities during static bite situation. The subjects were 4 males and 1female. EMG activities were registered bilaterally from the masseter muscle (MAS), anterior temporal muscle (AT) and posterior temporal muscle (PT) in different jaw positions anteroposteriorly. During EMG registration, bite force was regulated both in magnitude and direction with visual biofeedback by means of a three-dimensional bite force measuring device. The relative activation pattern of the muscles during bites in specific directions was consistent irrespective of jaw position. During bites in a specific direction at a determined force, MAS activity increased as the jaw position was changed anteriorly, while AT and PT activities increased as the position was changed posteriorly. The difference between activities generated in different directions was dependent on jaw position in AT and PT, but not in MAS. The difference between the activities generated at different bite forces was dependent on jaw position in MAS and AT, but not in PT. It was suggested that these characteristics of muscle activity as changes of jaw position might be closely related to the shape and spacial location of muscles.

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The purpose of this study was to clarify the normal relationships between anterior components of lateral occlusion and muscle activity of 12 healthy subjects. The location (LO) and area (AO) of occlusal contacts were measured by black silicone methods, frontal (FA) and horizontal (HA) angles were also measured by LED jaw tracking device at canine's edge to edge to lateral position (ED-LP) as an anterior component of lateral occlusion. Muscle activity of masseter muscle (Mm), anterior temporal muscle (Ta), posterior temporal muscle (Tp) were recorded bilaterally by bipolar electrodes during maximal voluntary clenching (MVC) at ED-LP.
The muscle activity during MVC was affected by anterior components, and the most effective muscle was the working-side Ta and Tp. In the case that frontal teeth with canine restricted on working-side LO, the reduction of muscle activity was observed as the reduction of AO or increase of FA. However, if the molar teeth were included on working-side LO, AO did not affect the muscle activity which could be decreased only by the increase of FA. If the working-side contacts were established, the balancing-side contacts did not affect the muscle activity of Mm, Ta, and Tp during MVC.

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Even bruxism has been considered as the main contributor to temporomandibular disorder for a long time, there are still some questions about detailed physiologic phenomena of this sleep motor dysfunction. The purpose of this study was to develop a new tracking device, which can measure jaw movement during bruxism in six degrees of freedom. The principal features of the device are as follows:
1. The device measures upper and lower jaw movements without any limitation so that the subject can be in any posture during measurement.
2. Whole elements of jaw movement in six degrees of freedom can be detected simultaneously.
3. Pilot study of jaw movement and simulated bruxism revealed sufficient efficiency and accuracy to analyze sleep associated bruxism.

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Occlusal surface that is employed for occlusal reconstruction is commonly determined by the clinician's experiments. There are no superior kinematics and scientific evidence that reveal occlusal shape. The purpose of this study was to establish a kinematics standard that determines the morphology of occlusal facet. In this study, a computer simulation model was developed to analyze three-dimensional interocclusal relationship during excursive movement. The main experiment involved the following investigations by using this computer simulation study.
1. Eighty-four types of simulated excursion were utilized to design corresponding jaw movement surfaces.
2. These jaw movement surfaces were investigated by analyzing interocclusal distance and interocclusal angle during excursion.
The results of this study showed that 29 types of simulated excursion could provide stable occlusal contacts at both intercuspal and lateral jaw positions, while others produced interference during excursion. Further researches will be required to confirm the fundamental relationship between jaw movement kinematics and ideal occlusal morphology.

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This study was carried out to compare the effectiveness of two methods using expandedpolytetrafluoroethylene (e-PTFE) membrane and another poling film (Vinylidene Fluoride-Trifluoroethylene copolymers) as barrier membranes on bone regeneration around the immediate implants to obtain stable initial fixation and osseointegration.
P3 and P 4 of six beagle dogs were removed and endosseous implants were placed into the remaining sockets. Group A's experiment site was covered with e-PTFE membrane, Group B's was covered with poling film, and the control group's was covered with only mucoperiosteum flap. Experimental periods were 2, 4, and 6 weeks; histopathological and bone histomorphometric observations were made.
Especially in Group B, a greater amount of bone tissue was observed in an earlier stage. Bone density and mineralization in Group A were almost the same as in the control group but inferior to Group B in all experimental periods. Bone histomorphometric values showed that rates of mineral appositional, bone formation, and bone contact ratio were lower with e-PTFE membrane than poling film.
From the results, both membranes had the potential to generate bone around dental implant. However, poling film had greater effect on activating bone formation and maturity of bone tissue than e-PTFE membrane in an earlier stage.

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