The purpose of this study is to investigate the relationship of food consistency to patterns of mandibular movement and jaw muscle activity during mastication in adults with normal dentitions.
Ten young people who ranged in age from 23 to 26 were studied. Specially made chwing gums of 3 graded consistencies (4.4×10², 1.4×10⁴, 1.3×10⁵ poise), not contain any additive like sugar and flaver, were used as test foods. Mandibular movements were recorded and analyzed using a Mandibular Kinesiograph (Myotronics Research Co.) during chewing of the 3 grades of chewing gums for 40 stroks. Surface EMG signals were also recorded from the bilateral masseteric and anterior temporal muscles. Displacement and velocity of jaw movement, duration of each phase, and amount of EMG activity were then statistically compared among chewing trials of the 3 grades of chewing gums with two way analysis of variance.
The results were as followed.
With the increase of consistency of chewing gum; 1. Maximal vertical, antero-posterior and lateral displacements were significantly increased (p<0.01).
2. Maximal opening and closing velocities were significantly increased (p<0.01).
3. Opening phase time was significantly increased while occlusal phase time was significantly decreased (p<0.01). Cycle time and closing phase time were about constantly.
4. Burst duration, interval and cycle time were about constantly.
5. Burst activity were significantly increased (p<0.01).
6. Burst co-ordination pattern was about constantly.

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The purpose of this study is to investigate the denture design and displaceability of residual ridge mucosa and its relation to the load distribution on the remaining oral structures.
In this study, the effects of the location of rest and displaceability of the mucosa were demonstrated utilizing the two-dimensional non-linear analysis reported on Part 1.
The results were as follows.
1. Mesial rest could be simulated on the finite element model using pin element.
2. Removable partial denture with mesial rest distributed more stress on the mesial abutment teeth than that with distal rest.
3. Lesser displaceability of residual ridge mucosa resulted in a decrease of stress concentration around the most distal abutment and the uniform stress distribution on residual ridge was increased.
4. In the simulated condition where an increased pressure was applied on the mucosa, the behavior of the saddle on the mucosa with large displaceability could be similar to that of the mucosa with small displaceability.
The results of this study suggested that mesial rest on the most distal abutment and pressure impression was desirable in removable partial denture with distal-extension.

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The purpose of this study was to investigate the state of the natural secondary caries and in vitro artificial secondary caries, associated with cast restorations cemented with zinc phosphate cement, histopathologically.
For this study, the method of making and staining ground serial sections of teeth with cemented cast restorations was established.
The material consisted of 50 extracted human parmanent teeth with cemented cast restorations, and 12 human premolar teeth with in vitro secondary caries produced by the acid-gelatin system (pH4.0).These specimens were embedded in MMA resin and then they were sliced to serial thin sections. Each section was etched by 0.1NHCl, and stained with methylene blue fuchsin, and then observed with optical microscope, microradiography, and SEM.
The result were as follows:
1. When the margin of restoration was set on dentine (cementum), the typical shape of natural secondary caries was found out.
2. The rate of natural secondary caries in case of margin set on dentine was about four times as many as the rate in case of margin set on enamel.
3. The shape of artificial secondary caries was very similar to the shape of natural secondary caries.
4. The resistance to secondary caries in case of the margin set on enamel was higher than the resistance in case of the margin set on dentine.

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The purpose of this study was to estimate masticatory efficiency of complete denture wearers. The subjects were 72 patients, treated before 5-10 years at students' clinic of Tsurumi University, School of Dental Medicine. The masticatory efficiencies with peanuts and Kamaboko were calculated.
Results
1. The mean masticatory efficiency with peanuts for 63 patients was 35.8%, and with Kamaboko (steamed fishpast) for 64 patients was 94.5%, in comparison with natural dentition.
2. The mean masticatory efficiency with peanuts was 124.3%, and with Kamaboko was 99.6%, for complete denture wearers.
3. Comparing the measured value of masticatory efficiency with 5 to 10 years wearing period, there was significant difference in the masticatory efficiency between peanuts and Kamaboko.
4. There was significant difference in the masticatory efficiency with peanuts between the group needed new denture and the group not needed but there was not significant difference with Kamaboko

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Filler contents, Knoop hardness, characteristics of cutting and surface texture of eight commercial composite resin cores were investigated. Two posterior composite resins and two silver alloys were used as controls.
No differences were found in filler contents and Knoop hardness between the composite resin cores and posterior composite resins. In the composite resins, Knoop hardness was correlated to the filler content. The characteristics of cutting with a diamond point varied largely among materials. The composite resin cores were divided by deterioration of the characteristics of cutting into two groups. The degree of surface roughness of composite resins polished with a finishing diamond point was larger than that of the silver alloys. SEM examination revealed little differences in the composite resin surfaces cut with a diamond point but large differences in surfaces polished with a finishing diamond.

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The present study was aimed at establishing the standards for functional diagnosis of the internally deranged TMJ by analyzing the rotary and gliding movements of the mandibular head. The subjects were patients with anterior displacement of the articular disc (ADD) and normal persons. The rotary movements were examined by use of a simplified condylar movement recorder and a specially developed dual axis graphic system.
The findings are as follows:
1. In the patients and the normal persons as well, the rotary movements near the intercuspal contact position (ICP) showed a tendency to increase anteriorly until the mandibular head moved up to 6mm from the ICP. However, in both patients with ADD with reduction and without reduction, the rotary movements near the ICP were significantly large as compared with those in the normal subjects.
2. In the ordinary persons, the rotary movements near the ICP were mostly larger during the closing movements than during the opening movements. In both patients with ADD with reduction and without reduction, the rotary movements were larger during the opening movement than during the closing movement.
3. The results of our study suggest that the dual axis graph could be a useful tool in examining the rotary movement of the mandibular head.

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Accumulation of glycogen in the epithelium of the oral mucosa was evaluated in relation to the existence of wound and inflammation of the oral mucosa histochemically and histopathologically.
Antemolar rhombus (the anterior part of the intermolar palate) of adult Wistar rat was employed as experimental area. Experimental wound of palatal mucosa was made by excision of crestal one third of the palatine ruga. Inflammation of the connective tissue was artificially induced by the insertion of silk thread or silk thread immersed in 5% formalin in the connective tissue parallel to the crest line of palatine ruga. The experimental area was examined histochemically and histopathologically up to 72 hours after experimental operation.
In excision wound the accumulation of glycogen was observed in prickle cell layer of the epithelium after 24 hours. Although the inflammatory reaction was observed more prominently in the thread inserted connective tissue, the accumulation of glycogen in the epithelium could not be detected.
The findings of this study suggested that inflammation itself does not induce the accumulation of glycogen in the epithelium of the oral mucosa and the accumulation could be an indication of wound and/or its healing process of oral epithelium.

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he purpose of this study was to evaluate clinically superplastic titanium alloy for maxillary complete denture.
The subjects that were the 30 patients with upper edentulous ridges were selected from Tsurumi University Dental Hospital.17 patients were maxillary and mandibular edentulous, the other patients were only maxillary edentulous. Each of metal base was made of 90 Ti-6 Al-4 V alloy by Sankin Dental Co. The portion of a resin was used of PMMA resin with 4-META (4-methacryloxyethyl trimellitic anhydride). At the time of inserting the denture and one month after, the dentures were clinically observed about the retentive force and the adhesive condition on finish line. At the same time, the patients were examined oral mucose and inqired of the feeling relating to wear new denture. Furthermore each weight of new dentures was compared with each of old dentures.
The results were as following:
1. The width and depth of the palate were measured previously on posterior palatal sealed area. The mean value of the depth was 8.8±1.8mm and the mean value of the width was 44.9±2.7mm.
2. The retentive force of new dentures was clinically adequate enough to achievement of function without two cases.
3. The adhesive condition on the finish line was adequate in all cases.
4. The mean weight value of the new denture was 20.1±3.9g.
5. 2 of 30 patients were finded the slightly redness without pain on the middle palatal mucose.
6. The feelings of patients relating to wear were as following:
1) Lighter than old denture. 2) More extensive tongue space. 3) Adequate retentive force. 4) More comfortable feeling for wearing without vomiting reflex.

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This study investigated the adhesive strength of cyanoacrylate dental adhesive, ‘F.H cement’ after being thermal-cycled in order to certify its stability in water.
The adhesive strength was compared using Zinc phosphate cement, Glass ionomer cement, Dental adhesive resin and F.H cement when an ivory die and a cast crown were adhered bythese different cements.
Results of the study indicated the following:
1. The adhesive strength after being thermal-cycled indicated that F.H cement had a greater strength than the other cements (Zinc phosphate cement and Glass ionomer cement) and was equal to that of the Dental adhesive resin.
2. F.H cement was also found to be the strongest in adhesive strength when different tapers were used.

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With the development of adhesive luting resins that adheres both dental alloys and tooth enamel has been widely used the resin-bonded fixed partial denture recently.
Since we experienced, however, that the metal retainers without mechanical retention such as channels were often dislodged with metal interface failure, the more durable bonding between a luting resin and a metal has been desired.
This study was undertaken to investigate the effect of microbeading onto the adherend metal surface on the tensile adhesive strength between an adhesive luting resin and a dental alloy.
Maxgold ^® equivalent to Type IV gold and Panavia EX ^® were used as an adherend metal and a luting resin, respectively.
The following conclusions were drawn:
1. Microbeading on the adherend metal surface made no contribution to an increase of the tensile adhesive strength, unless the adherend surface treatment was achieved. However, once 50μm alumina blasting and tin plating were achieved on the microbeaded metal surface, the tensile adhesive strength was significantly increased.
2. Taking into account the fabrication technique and the tensile adhesive strength, the optimum diameter of microbeads seems to be 150μm.
3. In the result of various accelerative durability tests (invasion tests in 70 and 100°Cwater, thermal cycling between 4 and 60°C water), the durability of 150μm microbeaded metal surface on which 50μm alumina blasting and tin plating were achieved was much better than that of the smooth metal surface.

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In this study we examined the shearing adhesive strength between a calcium metaphosphate glass-ceramic (CMP) and various luting materials. Two usual luting cement-zinc phosphate cement (Elite Cement 100), glass-ionomer cement (Fuji ionomer cement Type I) and three adhesive luting resin-Super Bond C & B, Panavia EX and a tentative luting resin were used as the material. We also examined the effect of three adherent surface treatments-50μm Almina blasting, hydrofluoride etching, and sodium hydroxide etching-on the adhesive strength of the two adhesive resin, Panavia EX and the tentative luting resin, to CMP.
The following conclusion were drawn:
1. The adhesive strength to CMP surface polished with #600 emery paper was higher in order of Super Bond C μ B, a tentative luting resin, Panavia EX, Fuji ionomer cement Type I and Elite Cement 100.
2. Sodium hydroxide etching was the most effective for the adhesion between the adhesive luting resin and CMP among the above four adherent surface treatments.
3. Irrespective of the etching time, the stimulation of sodium hydroxide bath by supersonic waves gave an additional increase to the adhesive strength.
4. Under the stimulation by supersonic waves, increasing sodium hydroxide concentration tends to increase the adhesive strength, whereas it is little affected by the etching time within three minutes. The maximum was obtained with concentration in four or five normal (4 or 5N) sodium hydroxide.

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The purpose of this study was to investigate mandibular position sense with four different jaw openings (5, 10, 15and20mm from intercuspal position) during open-close movements. Eight subjects memorized the reference positions with monitoring their spatial vertical jaw positions using a Mandibular Kinesiograph (M.K.G., K-5). Immidiately after memorizing one of those positions, they were required twenty times open-close movements; that is, approaching the memorized position from superior (opening approach) or from inferior position (closing approach) and receding were repeated. Vertical distances from intercuspal position at lower incisal teeth were recorded by MKG and statisticaly analyzed.
1. In the closing approach, perceived mandibular positions were become lower, but in the opening approach, significantly higher than reference positions (5mm: p<0.00001, 10mm: p<0.05, 15mm: p<0.025, 20mm: p<0.005).
2. In the closing approach, the inclination of regression lines shows significantly the estimated decrement to come near closed position throughout twenty experimental sequences (5mm: p<0.001, 15mm: p<0.025).
3. On 5mm reference position, variance of data was significantly lower than the others. On 10mm with opening approach, it was the highest of all.
4. It was suggested that mandibular position sense was affected by mandibular spatial vertical position and direction of approaching during jaw movements, and that neuronal mechanism of controlling mandibular positions and movements were more excellent near tooth contact.

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In order to establish a new operative method of mucosalplasty in the edentulous ridges to improve pontic adaptation, newly revised diamond points were produced and tested. The efficiency of these diamond points were tested on the edentulous ridges of dogs in relation to its shape, size of the diamond particle, and appropriate rotational speed, and the tissue damages and healing processes were observed under a light microscope and SEM.
The results were as follows;
1. Light microscopic observations showed immediate post operative necrosis of the wound surface, and degeneration below the necrosed layer of high rotational speed diamond points.
2. Tissue damage became larger as the size of the diamond particle increased, but there appeared to be no influence upon the healing process of the wound.
3. Tissue damage also became larger as the diameter of the diamond point increased, but again no influence upon the healing process was observed.
4. Middle to low rotational speeds showed no differences in tissue damage or wound healing, but high rotation caused larger tissue damage and prolongation in the healing process.
5. The most suitable condition for mucosalplasty revealed the size of the diamond particle to be200μm, and rotational speed to be between12, 000-20, 000rpm.

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1. The state of inclination and the change under various conditions of the imaginary axis of the tooth crown of upper jaw anterior teeth can be determined by the image measuring system and method of this study.
2. The measurement error of this system was not more than 0.3 degree. This value was sufficient for the purpose of this study.
3. The imaginary axis of the tooth crown of anterior teeth was determined on the study cast with 1 to 3 degree in mesiodistal direction and 2 to 4 degree in labiopalatal direction as standard deviation.
4. The imaginary axis of the tooth crown of anterior teeth was determined toward labial in the random position and toward patient's right and palatal in Standing Posture.
5. It was confirmed that the determination of the imaginary axis of tooth crown was effected by the position of the patient relative to the operator, limitation or direction of view, and approach direction.

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The purpose of this study was to observe marginal leakage of complete crowns cemented with zinc phosphate cement and adhesive cement as determined by RI. After repeating load the samples were placed in gelatine solution with ³⁵SO₄⁼ labeled compound.
1. Most of complete crowns cemented with zinc phosphate cement showed remarkable marginal leakage as long as the entire length of the interface.
2. Complete crowns cemented with adhesive cement showed very little marginal leakage, a maximum depth of 0.53mm from crown margins.
3. The repeating load test manifested proper position of crown margin, that is, the crown margin should be placed at least 1mm far from the dowel core margin using adhesive cement.
4. The marginal distance of gaps was presumed from autoradiograms by using the regressive formula calculated from the relationship between the distance of gaps and the film density in Part 1.

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The study demonstrates the relationship between palatal formation and human utterrance by PARCOR analysis. PARCOR (partial autocorrelation) coefficient ‘k’ in speech wave was derived from the conception of linear prediction of human speech production by ltakura. Linguistic opposition was also adapted for the evaluation of plate forms and positions. Investigations were conducted to six adult men as the subjects who wore the experimental plates divided by four steps. PARCOR coefficients of the plate wearer's sounds were shifted as the plate area increase, and linguistic oppositions were individually proposed. Conclusions were represented as follows; Phonetic opposition of /p/×/m/ and /d/×/m/(in ‘stop’ to ‘nasal’ opposition) were influenced by the width of the plates. Opposition of /t/×/s/(in ‘stop’ to ‘fricative’ opposition) was significantly influenced by the frontal positions in oral cavity. Phonetic oppositions were also influenced from vowel environments to the consonants. As the plate areas were increased in order of full plate, 1/2 plate and 1/4 plate, the evidency of the oppositions were decreased.

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Ten patients received augmentation of deficient mandibular alveolar ridges using particulate hydroxyapatite (HAP).
Masticatory ability was evaluated preoperatively and postoperatively by a questionnaire with 35 foods listed and by the spectrophometric method using ATP granules. The results showed that masticatory ability when wearing newly constructed complete dentures was significantly enhanced compared to that when wearing old dentures or relined dentures, and that the surgical procedure and the use of the surgical stent greatly improved masticatory ability when wearing the new dentures.
The sensitivity of the mucose membrane of the augmented mandibular alveolar ridge was examined during a postoperative period of 24 months by using an electric nerve stimulator. The sensitivity of the mucose membrane decreased postoperatively, especially at the buccal site of the molar region, the so-called buccal shelf. The level of sensitivity increased periodically, and did not return to the average level for normal edentulous mucosa even 24 months after the augmentation.
The patients were highly satisfied with the new dentures and the HAP augmentation judging from the questionnaire.
From these points of view, HAP augmentation in edentulous patients having severely resorbed alveolar ridges has proved to be benficial in allowing the recovery of masticatory function.

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In order to evaluate the strength of titanium-hydroxyapatite implant, adhesive tests and loading tests were performed. The results of the loading tests were compared with the computed results by finite element method.
Axisymmetric 8-node quadrilateral element for arbitary loading was used for the analysis. Implants of 3.2mm diameter were loaded at 45°of the implant axis by using an Instron testing machine at crosshead speed of 0.5mm/min.
The results were obtained as follows:
1. The mean value of the adhesive test of titanium-resin (Panavia)-hydroxyapatite was 2.3 kgf/mm². The fracture was caused at Panavia layer.
2. The mean value of the fracture loads of implants was 10.9kgf. The fracture was caused at Panavia layer, similarly to the result described in 1.
3. The principal stress caused at Panavia layer of the implant was approximately 2.3kgf/mm², which was calculated under the load of 10.9kgf by the finite element method. This result corresponds to that of the loading test described in 1 and 2.
It was ascertained by these findings that finite element method is effective for the evaluation of the strength of this implant.

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Previous studies found that the adhesive resin provided strong adhesion to alloys. Also, the bond durability was improved by oxidation of alloys.
In oral, many aciditic substances exist. However, the oxides yielded by oxidation are unstable in aciditic environment. Thereupon, the adhesive resin systems should be studied in aciditic environment.
In this study, half of the alloy disks were air-brushed with alumina and the remaining half were polished with #600 emery. They were then ion-coated. One third of the disks were with Cu oxide another one third were Cu·Sn oxide, and remaining were Sn oxide. The handle was affixed by the 4-META resin. For reference, Co-Cr specimen oxidized ultrasonically was fabricated. Completed specimens emery polished were stored in lactic acid at 37°C for 3 months, and sand-blasted were for 6 months. Then the tensile strength was measured.
In 0.002% solution, initial bond strength of all the specimens was maintained after immersion. After 1.0% immersion, bond strength of Cu oxide coating specimen polished with emery decreased rapidly. Bond strength of Cu·Sn oxide and Sn oxide coated specimens decreased slowly. Sand-blasted specimens showed higher durability than emery polished. Co-Cr alloy specimen showed the highest durability, and 260kgf/cm² was maintained after 6 months in 2.0%.

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Several researches have been reported on the mechanism and movement of Gysi Simplex OU articulator. And it was clarified logically by geometrical drawing method that the movement of the ariticulator followed the Gysi's axis theory. But no study reported about the movement of the articulator by mesuring it.
Therefore, the authors mesured the movement of the articulator with Kyushu University 3-D movement analyzing system, and compared it with the results obtained from geometrical drawing method which we reported previously.
The following results were obtained
1. The rotational point exists actually at the same position where we analyzed by geometrical drawing method.
2. Lateral axis is constructed by joining the rotatinal points at various height.
3. The inclination of lateral axis changes by sagittal inclination of incisal guidance.
As the results, we clarified that the movement of Gysi Simplex OU followed the Gysi's axis theory.

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Masticatory function of 10 telescope denture wearers in the Kennedy class II mandible patients was evaluated with electromyography.
Electromyographic activity during mastication with kamaboko and peeled raw carrot was recorded from bilateral masseter and the anterior part of temporal muscles at each interval: Before treatment, immediately after denture insertion and 2, 4, 6, 8 weeks after respectively. Mean of duration, interval and cycle of EMG activities, coefficient of variation andaverage variation were calculated.
The results were as follows:
1. Means of duration and cycle timesd ecreased immediately to 2 weeks after denture insertion.
2. EMG activities during raw carrot chewing became regular immediately to 2 weeks after denture insertion, and within 4 weeks in kamaboko chewing.
These results suggest that telescope dentures would be adapted to stomatognathic system within short period after denture insertion.

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The purpose of this in vitro study was to compare the dimensional accuracy of maxillary dentures made using a conventional heat-activated PMMA resin, a pour resin, a visible light-activated resin, and a microwave-activated acrylic resin.
Two simple methods for measuring dimensional accuracy were used:(1) weight of impression material entrapped between the base and master die and (2) measurement of the posterior border gap at five locations. The volume of space between the denture base and the master die was determined by (1) computation and (2) estimation. Statistical analysis (Bartlett, ANOVA and Tukey's Tests) supported the following conclusions:
(1) all groups showed a processing contraction, most apparent from buccal flange to buccal flange,
(2) the poorest fitting group was processed in a brass flask and a water bath at a temperature which rose from 70 to 100°, using a heat activated resin (Acron),
(3) the visible light activated resin (Triad) produced dentures of intermediate accuracy, as did Acupac 20 when either heat or microwave activated,
(4) the two best fitting groups were prepared from a chemically activated resin system using pressure at low heat (PER form), and the resin developed for microwave activation (Acron MC).

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This study evaluated the effectiveness of ion exchange on strengthening of porcelain used in metalceramic. The paste for ion exchange was painted directly on the porcelain surface, dried, and heated at 450°C in the porcelain furnace. The bending strength of porcelain test samples (6.5×1.5×20mm), the compressive strength of porcelain-fused-to-metal (PFM) crowns, which were cemented on the metal dies of upper central incisor by an adhesive luting resin ‘Panavia EX’, and the color change of porcelain test samples (φ10×4mm) were measured before and after ion exchange.
The conclusions were:
1. It was confirmed by X-ray analysis that the compressive stress layer generated by ion exchange for 30 minutes was 150-200μm in thickness. However, further elongation of time of ion exchange elicited no significant argumentation in the strength.
2. 34 or 57 percent increase of the mean compressive strength of PFM crowns was observed after ion exchange for 30 minutes when the load was applied in the direction of 45° lingually to the tooth long axis or of the tooth long axis, respectively.
3. No significant decrease was found when parts of the incisal edge or the lingual surface of PFM crowns which were strengthened by ion exchange for 30 minutes were reduced by 200μm.
4. There was so slight difference in the color of dental porcelain before and after ion exchange that the influence seemed to be negligible in its clinical application.

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