Many patients with temporomandibular joint (TMJ) disorders complain of various symptoms such as headache, shoulder stiffness, dizziness, tinnitus or other symptoms in addition to the three main TMJ symptoms (pain in the TMJ and masticatory muscles, limited mouth opening and TMJ noises). It has been shown that the side in which the patients complainof such accompanying symptoms most frequently coincides with that of the TMJ symptoms, and that the accompanying symptoms are often improved in parellel with the improvement of TMJ symptoms. These clinical findings suggest that the accompanying symptoms can be caused bythe same mechanisms as TMJ symptoms. However, the studies regarding the relationship between stomatognathic dysfunction and body condition are extremely limited.
The purpose of this study was to investigate the relationship between TMJ dysfunction and body posture. In this study, 20 subjects with unilateral disk displacement of the TMJand 20 subjects without TMJ disorder were examined. All of the two groups were ordered to relaxand stand upright in front of a video camera. We registered theirwhole body postures andmeasured 10 and 6 angles from frontal and lateral views, respectively, by use of an image analysing computer system. Comparison of the angles between the two groups was made.
In the result, we could point out several characteristic body postures of subjects with disk displacement.
In the frontal view, an upper midpoint of the body (a midpoint of the lateral malleoli, the anterior superior iliac spines, the jugular incisure and the glabella) of subjects with disk displacement tended to deviate to the TMJ symptom side in comparison with a lower midpoint, and all the lines connecting between both eyes, bothtragi, both mouth angles, both mandibular angles, both acromions and both anterior superior iliac spines tended to rise to the TMJ symptoms side. The chin tended to shift to the TMJ symptom side.
In the lateral view, no statistical differences of body postures between normalsubjects and subjects with disk displacement were observed.
These results might indicate that the change of body postures plays some roles to cause ‘other’ symptoms accompanying TMJ disorders.

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Postural adjustments and voluntary movement appear to be parts of thesame motor program. Anticipatory postural movements should result from muscular functionalsynergies selected from a pre-evaluation of the perturbative aspects of the forthcoming movement. The present study was designed to investigate the relationship between anticipatory postural activities of the sternocleidomastoid muscle (SCM) and peripheral processes associated with execution of the voluntary movement. When subjects executed wide jaw opening as rapidly as possible at the acoustic signal, the following results were obtained:
1. Relations between firing latencies of the SCM and reaction time (RT) were highly signifi-cant. However, firing latencies of the SCM had no relation with motor time (MT).
2. Anticipatory postural period of SCM's activities which preceded the burst of Da had no correlation with opening distance, opening velocity, and MT. These results suggested that anticipatory postural activities of SCM were not associated with peripheral processes of voluntary rapid jaw opening.

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The purpose of this study is to develop the three-dimensional shape measurement system for the casts of edentulous jaws. This system was equipped with a high precision laser displacement meter and a scanning machine controlled by a personalcomputer. The HIP plane was utilized as reference to standardize the shape measurement procedure for residual ridges. The data measured by this system were analyzed with the programs we developed as follows. The crests of ridges and mucobuccal folds were searched automatically. The parameters of morphological factors such as the height and the width of residual ridges and arches were calculated from these anatomical reference points. Four kinds of pictures were prepared for displaying the analysed results. The first and second ones showed 12 serial sagittal and frontal cross-sectional contours for each cast. The third displayed a cross-section with the value of parameters and the last was three-dimensional graphics of the entire cast shape. We could observe and analyze the shape of residual ridges with computer graphics and save these data on floppy disks by this system. It was suggested that this system could be useful to design complete dentures and to estimate the prognosis of denture treatment.

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The relationship between the muscle fiber conduction velocity (MFCV), EMG frequency parameters and the occlusal vertical dimension was studied in the human masseter muscle in three normal subjects (24-27yr.). Occlusal vertical dimension was changed from the intercuspal position (ICP) to the maximum bite-raising position (12.8mm) using five different occlusal splints on the habitual opening-closing movement path. Each subject was instructed to clench on each vertical dimension at 10, 30 and 50% maximum voluntary contraction. EMG signals were detected with a surface linear electrode array with 13 contacts placed along the muscle fibers. The MFCV was calculated from the time delay between adjacent EMG signals. The frequency parameters were 10, 25, 50 and 75% cumulative power functions and mean power frequency.
The results obtained were as follows:
1. The MFCV was increased with the contraction level and decreased with the occlusal vertical dimension.
2. The EMG power spectra were slightly shifted to lower frequencies with the occlusal vertical dimension.
3. The MFCV showed a large change in the vicinity of ICP with a slight change of muscle length. It was suggested that the MFCV in ICP was an important index for occlusal reconstruction.

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It is supposed that great influences are recognized for the stomatognathic system by natural and premature loss of canine.
For the case of TMJ syndrome with the background of unilateral canine defect, attrition of remaining caninus dicidus and working side posterior molar causing premature contact with the balancing side, we carried out morphological examination of the dental arch and TMJ by using three-dimentional high elaborate razor and X-ray. We obtained the following results.
1. Excluding the premature contact with the balancing side, disappearance of trismus and pain were recognized.
2. Attrition of canine defect side molars, especially on palatal surface, were stronger than the other side may indicate the possibility of a shortening vertical dimension.
3. Palatal form of canine defect side was narrow and inclined. So the dental arch was near the median line.
4. X-ray of canine defect side showed a shallow glenoid fossa and modification of the condyle.

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Surface electromyogram was utilized as one of the diagonostic methods for patients with craniomandibular disorders to investigate masticatory muscle contraction. We attempted to determine normal ranges of asymmetry and activity indices, proposed by Naeije M.et al., in masseter and temporal muscles during intercuspation at the clenching levels of 10%and 50% maximum voluntary contraction (MVC).
Normal ranges were calculated with the parametric statistics on the asymmetry index in 88 males and 75 females (mean 22.7 yr.), and on the activity index at each side in 47 males and 39 females (mean 22.5 yr.).
Significant differences of asymmetry indices were found between sexes, between muscles and between clenching levels (p>0.05).Normal range of asymmetry index at 10% and 50% MVC was respectively:-51.57 to 64.69 and -39.19 to 34.07 for the masseter muscle and -56.42 to 71.51 and-32.99 to 29.65 for the temporal muscle in males;-35.79 to 58.83 and-27.82 to 29.71 for the masseter muscle and -30.90 to 51.97 and -20.12 to 26.01 for the temporal muscle in females. Positive value indicated right side prevalence.
No difference of the activity index was found between right and left sides.Normal range of activity index at 10%and 50%MVC was respectively:-94.22 to 35.85 and -38.84 to 44.13 in males;-81.98 to 6.19 and -49.49 to 27.36 in females (the negative value indicated dominance of the temporal muscle).

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Recently, powder-liquid V.L.C.reline materials have become popular in Japan.Jinichi Obana advocated the direct reline method in 1971.
We have studied this procedure and finally developed a new direct reline material-“REBARON LC”by G.C.Corporation-which is light cured.We have performed various basic experiments and used them in clinical tests.“REBARON LC”was formerly compared with chemical-cured or one paste V.L.C.reline materials. Formerly, we didn't compare it with this powder-liquid category of materials. So, I imported some powder-liquid V.L.C.reline materials.I have used these materials and studied their characteristics, fluidity, consistency, compression set and strain in compression before light-curing.
The results were as follows:
1.The fluidity of powder-liquid V.L.C.reline materials, except“Light liner”, decreased each time when used.
2.The consistency of“Extoral”, “astron L.C.”and“Light liner”at room temperature decreased slowly, but“REBARON LC”showed the most significant decrease in consistency.
3.The consistency of all four powder-liquid V.L.C.reline materials showed rapid change within 5 minutes.
4.The consistency was influenced considerably by temperature.
5.The compression set of“REBARON LC”(before curing) was the smallest of other reline materials and after 17 minutes it became similar to alginate impression materials.
6.Strain in compression of the higher four powder-liquid V.L.C.reline materials showed 1-3 times more than alginate impression materials.

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A photoelastic stress analysis technique has been conducted for many years as a test to analyze stress distribution of porcelain jacket crowns under a load. The purpose of this study was to evaluate the alteration of stress distribution on ceramic jacket crowns by each abutment material of different elasticity. On the assumption that the jacket crown consists of castable ceramics (DICOR) and three different abutment materials had metal cores (12% Au-Ag-Pd alloy), a resin core (photocuring composite resin) and a natural tooth, the crown and the abutment tooth model were made of epoxy resin. And the stress analysis of the ceramic jacket crown was studied by three-dimensional stress freezing photoelasticity experimental technique.
The boundary stress in the portion with the added load reached the maximum value in all abutment teeth. The magnitude of boundary stress increased with the decrease in the elastic modulus of the abutment material. Especially, when the abutment was a resin core or a natural tooth, high boundary stress was observed around the labial cervix.

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In continuation of our studies concerning composite resins for dowel-cores, a new dentin primer was examined to improve the retentive force of prefabricated posts to the dentin.
In this study, four series of treatment procedure to be performed on the root canal dentin before cementation and no treatment as the control were examined. After dentin treatment, prefabricated posts were cemented with dual-cured composite core resin and adhesive resin cement. Then their early retentivities were measured and compared with one another.
The following results were obtained;
1. A new dentin primer, Teeth Primer, was very effectivity for improving the retentivity of prefabricated posts in the root canal.
2. When using dual-cured composite core resin as a luting agent, the combination of Teeth Primer and Clearfil Photo Bond was the most recommendable for clinical use, because of its short treating time as well as the very high retentive force. It means that the fixation of prefabricated posts in the root canal and the fabrication of composite resin cores can be performed at the same time.
3. When using paste-type Panavia as a luting agent, acid etching was really effective for retention of the posts. However, the single use of Teeth Primer was estimated to be more desirable clinically because of its shorter treating time.

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To understand age and sex differences on masticatory functions, the following experiments were performed on 46 subjects, who have intact dentition without stomatognathic dysfunction. The subjects were classified into four groups: 4 elderly men (59.2±6.8 years), 6 elderly women (60.5±3.5 years), 26 young men (24.1±2.1 years) and 10 young women (23.1±2.6 years). And the masticatory efficiency and muscle activity during chewing the testing gumi-jelly (Glico Co., Osaka) were examined.
Firstly, the masticatory efficiency was evaluated by using the amount of gelatin dissolved from the surface of the gumi-jelly after chewing a given number of times. This technique was based on the fact that gelatin was the only protein contained in the gumi-jelly, and the amount of dissolved gelatin was almost proportional to the surface area of the gumi-jelly.
Secondly, in order to examine the rhythm of muscle activity and the integrated muscle activity during chewing the gumi-jelly, electromyographic activities were obtained from the anterior part of temporal muscles and masseter muscles with surface electrodes bilaterally.
Consequently, there were no significant differences between the four groups concerning the amount of dissolved gelatin and the stability of muscle activity. The integrated muscle activity per stroke of young subjects tended to be higher than that of elderly subjects. And that of men also tended to be higher than that of women.

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Working casts were produced using three types of impression technique and impression material used for impression in the Branemark implant system, and the distortion of these casts was measured with a three-dimensional coordinate measuring machine. The three techniques were a technique in which a gold cylinder is splinted with autopolymerizing acrylic resin (gold-cylinder technique), a technique using squared impression coping (squared technique) and a technique using tapered impression coping (tapered technique). The three types of material were Examix Injection Type (Examix), Impregum F (Impregum), and Aroma Fine (Aroma). Based on the measurements, abutment replica distance, angle and height, which are considered the conditions of fit for the superstructure, were calulated by analytical geometry. The dimensional accuracy of the casts fabricated with each technique and material was compared.
1. The abutment replica distance was influenced by the impression technique. At all measured abutment replica distance sites, distortion of the gold cylinder technique and squared technique was less than the tapered technique.
2. The abutment replica angle was strongly influenced by the impression technique. At all measured abutment replica angle sites, distortion of the gold cylinder technique and the squared technique was less than the tapered technique.
3. Concerning the abutment replica height, result of using the tapered technique varied greatly. At all measured abutment replica height sites, distortion of the gold cylinder technique was less than the squared technique.
4. The impression material had no effect on the abutment replica distance or angle. At 2 of the 4 measured abutment replica height sites, distortion of Impregum was less than Aroma when the gold cylinder technique or squared technique was used.
5. The impression material had less effect on the dimension accuracy of working casts than the impression technique.
6. The use of the gold cylinder technique and Impregum provided working casts of high dimensional accuracy.

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Following the previous report, the temperature and distortion of flat 2 mm thick dumbbell specimens were measured by using thermocouples and Rosette strain gauges as a condition for cooling in tap water.The measurement was done whil processing, cooling, deflasking, and storage in 37°C water for seven days.
The results obtained were as follows:
1.The temperature of the specimen decreased closely to water temperature by approximately 30 minutes in tap water after processing.
2.The amount of distortion in the specimen was equivalent to the last occasion while processing, whereas, the contraction from completion of processing to deflasking was increased 5-8% as much as the occasion of bench cooling.
3.After storage in warm water, it was implied that the recovery of distortion was slightly delayed in comparison with the specimen of bench cooling.

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The ultimate purpose of these series is to manufacture the most effective surface treatment agent for repairing or relining denture base resins. As the preliminary step, the effects of chemical etching of the base resin by surface treatments with sixteen organic solvents on the bond strength between base resin and repair resin are presented in this report.
The results of the investigation are as follows:
1. Treating the surface of the denture base resin with chloroform, 1-butanol and ethyleneglycolmonobuthylether for 30 seconds before bonding of repair materials significantly improved the bond strengths between base resin and repair resin.
2. The bond strength was significantly decreased by treatment with ethyl acetate and xylene for 30 seconds.

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The speed analysis of mandibular movement is one of the most useful methods which give important information for evaluating the stomatognathic function. The purpose of this study is to clarify the characteristics of the speed at incisor, molars and condyles during jaw opening and closing movement. Mandibular movements were measured with Kyushu University 3-D movement analyzing system in 40 normal subjects then the speed was calculated.
The following results were obtained:
1. The averages of maximum speed were 253.42 mm/s during opening, 311.92 mm/s during closing at incisors; 173.14 mm/s during opening, 197.50 mm/s during closing at molars ; 91.82 mm/s during opening, 157.24 mm/s during closing at condyles. The value of maximum closing speed was significantly larger than that of maximum opening speed for each portion.
2. The averages of the moved distance where the reached maximum speed expressed as a percentage against the maximum moved distance were 32.46% during opening, 63.75% during closing at incisors ; 33.45% during opening, 62.76% during closing at molars ; 47.26% during opening, 58.63% during closing at condyles.

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The movements of right and left condyles and intercondylar axis were analyzed using Kyushu University 3-D movement analyzing system, and the following results were obtained.
1. In the rotation type of working condylar movement, the intercondylar axis rotated mainly around the working condyle, and the non-working condyle showed very slight internal sideshift.
2. In the shift type and the winding type of that, the lateral mandibular movement was the combination of the intercondylar axis rotation and the bodily sideshift.
3. In the external sideshift type and the winding type, the non-working condyle showed apparent internal sideshift.
4. In the internal sideshift type of working condylar movement, the nonworking condyle showed slight external sideshift, that was as large as the internal sideshift, and almost straight forward movement.
5. In all types of working condylar movement, the rotation angle of the intercondylar axis showed no difference.

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We previously studied distribution of stress-bearing at the centric occlusion in basal tissues of complete maxillary denture. Furthermore, we studied it at each occlusion on the right side, the right rubber molar, the right resin molar and bilateral balance.
The results were as follows:
1. Right side occlusion (right)
Stress-bearing of the residual ridge, basal margin, buccal region, palate and post dam in the centric occlusion increased especially from the basal margin to the palate including the incisive papilla, but decreased in range from the balance basal margin to the palate.
2. Right rubber molar occlusion (rubber)
Comparing stress-bearing of the residual ridge, basal margin, buccal region, palate and post dam in the centric occlusion with that on the right, there was significant elevation from the masticatory basal margin to the palate, but reduction in the incisive papilla and median palate.
Stress-bearing from the non-masticatory basal margin to the palate significantly decreased except for the maxillary tubercle, buccal region and basal margin.
3. Right resin molar occlusion (resin)
Comparing stress-bearing in the centric occlusion with that on the right and on rubber, there was an elevation ranging from the masticatory basal margin to the palate, but reduction in the median palate. Stress-bearing of the incisive papilla was markedly lower than that on the centric occlusion and on the right, but higher than rubber.
The stress-bearing from the non-masticatory basal margin to the palate decreased. It was at a negative level in maxillary mucosa and was within normal limits in maxillary bone.

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To study the bonding durability of metal-resin bonding systems, thermocycling test is one of the most important methods. However, researchers have adopted various kinds of test conditions such as specimen size, shape, immersion period for each bath and number of thermocycles, etc., and it is difficult to compare the results of thermocycling test with each other.
The immersion bath of higher temperature is also an important factor. However, there is no established temperature and the values reported in the literature show substantial variation and are distributed from 40 to 70°C.
In this study, adhesive specimens were constructed applying three bonding systems for resin -retained dental alloy. Completed specimens were thermocycled 20, 000 times at three hot bath temperatures of 50°C, 60°C and 70°C. Tensile and shear adhesive bond strengthwere then measured.
Increasing the immersion temperature, bond strength of all specimens decreased.However, the difference in bond strength between 50°C and 60°C specimens was not statistically significant at the p<0.01 level. At the temperature of 70°C, VBATDT primer system showed more durability than traditional adhesion systems which need oxidation surface treatment.

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A current study was undertaken to assess pronunciation of plosives in6 adult patients who had undergone a partial resection of a maxilla and had used a maxillary prosthesis for more than seven months. The test sounds for evaluation were/b, t, d, k, g, and r/, and their acoustic characteristics were compared by two methods: a speech intelligibility test (SIT), and a spectrographic analysis by Digital Sonagraph (DSG). Each patient's spectrographic pattern (sonagram) was analyzed for clearness of the oral silent period prior to the plosive, the spike fill, and the transition to the succeeding vowel. Aberrations in the pattern were graded on the basis ofnumeric scale, with a three representing the least aberrant pattern, and a zero, the most aberrant pattern. The time factor for each consonant was also assessed by DSG by means of an expanded time-wave display.
The results of this evaluation revealed the following:
1. SIT made it possible to evaluate an improvement in speech, if the defect wascomparatively small. However, it was difficult to estimate changes in sound when the defect involved the soft palate.
2. In cases of a major defect, DSG evaluation could determine an improvement inarticulation that was even perceived by the patients.
3. Based on the duration of the plosive consonant, it seems possible to assess changes in articulatory movements and the patient's adaptation to the prosthesis.

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It is important to grasp the functional characteristics of open bite, because open bite subjects have anterior guidance problems and many of them show TMJ dysfunction. However the effect of open bite on stomatognathic function has not been clarified.
The purposes of this study are to investigate 1) the characteristics of chewing patterns in subjects with open bite and 2) the relationship between each abnormal chewing pattern and stomatognathic dysfunction.
Fourteen normal subjects were selected as a control group, and 30 open bite subjects were selected and clinically classified by the location of open bite and the conditions of stomatognathic function as follows:
1. anterior open bite without dysfunction
2. anterior open bite with dysfunction
3. anterior and posterior open bite without dysfunction
4. anterior and posterior open bite with dysfunction
Chewing movements of each subject were recorded and qualitively analyzed by Sirognathograph Analyzing System II.
As a result, characteristic chewing patterns were observed in subjects with open bite, some of which have relationships with the location of open bite and stomatognathic dysfunction.

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The interdependent relationship between functions and forms in various vital tissues also exists in the maxillofacial area. In the present study, the correlation of lateralized mastication index (LI) with the assymmetry of constituting elements of the maxillofacial form was examined on the assumption that masticatory lateralization in the masticatory movement representative of stomatognathic function, i.e. long-term, persistent lateralized mastication is mainly responsible for the assymmetry of the maxillofacial form. As a result, it was observed that the facial form presented a relatively narrower width on the non-habitual chewing side than on the habitual one and that combined lines of cheilion tended to be inclined to the habitual chewing side.

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ln recent years a number of porcelain laminate veneer systems have been developed for possible esthetic advantages and minimal tooth reduction as alternatives to metal ceramic restorations. Although these laminate veneers must be bonded to the etched surface of the abutment tooth, luting materials were not discussed sufficiently for the luting operations.This investigation evaluated four light-cured luting materials, CLAPEARL (CP), COSMOTECH (CT), LAMINABOND (LB) and OPTEC (OP), for film thickness, inorganic filler content, filler particle size and viscosity before light curing.
The results obtained were as follows.
1.The film thickness of four light-cured luting materials under 5 kgf load was comparatively smaller than that of glass-ionomer and resin cement.And the film thickness was within 25 pm, and was not effected by applied load and loading time.
2.The inorganic filler contents (wt%) were about 62% for CT, LB, OP, and 69.8% for CP. The filler particle size was within 10 pm, and its shape was irregular.
3.The reduction ratios of viscosities of four light-cured luting materials in the range of 20-40°C were-3.7%/°C for CT, -4.6%/°C for KP, -4.0%/°C for LB, and-3.7%/°C for OP.

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The purposes of these series are to firmly join denture base resin to metal foundations of removable partial denture with adhesive metal primers.
In this report, the effect of four adhesive metal primers on the shear bond strength of a pour -type denture base resin bonded to silver -palladium-copper-gold alloy was tested. The adhesive metal primers used for this study were METALPRIMER, CESEAD OPAQUE PRIMER, New METACOLOR OPAQUE BONDING LINER, and ACRYL BOND.
The specimens were thermocycled in water for up to 5, 000 cycles at 4to 60°C, and the shear bond strengths were recorded.
The results of the investigation are as follows:
1. The four adhesive metal primers significantly improved the bond strength between base resin and alloy.
2. Sn-plating treatment significantly improved the effectiveness of four adhesive metal primers.
3. The pour-type base resin was bonded most strongly to alloy with CESEAD OPAQUE PRIMER following 50μm alumina sandblasting and Sn-plating after, 5, 000 cycles thermocycling.
4. METALPRIMER was most effective with only alumina sandblasting.

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Intercuspal position (ICP) is the most important position in all functional mandibular positions for the stomatognathic system. While the clenching level was gradually increased, dynamic stability of the ICP in 10normal subjects and 10patients with temporomandibular disorders (TMD) was evaluated from occlusal contacts, deviation of the incisal point of the mandible and bilateral anterior temporalis and masseter muscle activity.
The obtained results were as follows:
1. Increases in the clenching level produced changes in the location of occlusal contacts of ICP in TMD patients.
2. During clenching of ICP, displacement of the mandible in TMD patients was greater than in normal subjects.
3. During clenching of ICP, activity of the masseter muscle had a greater effect on the occlusal contact stability than the anterior temporalis muscle.

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Six types of resin-retentive devices with different inter-bead distance were prepared and tensile bone strengths between metal specimens and opaque resins were evaluated.Maximum bond strengths were achieved when the inter-beads distance was one half of the beads-diameter or when the inter-beads distance was equal to the diameter of the retentive bead particle.
The effect of a metal adhesive primer combined with mechanical retentive devices on bond strength between metal substructure and opaque resin was also evaluated.The potential of reduction of mechanical retentive devices using metal adhesive promoter was examined by means of tensile test and dyepenetration test.The results suggested that the retentive beads may be approximately 40% removed when a metal adhesive primer was applied to the metal substructure.

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