Part I and II of this study described the development of a very effective sandwitch -type dental magnetic attachment through various fundamental and clinical investigationsi. The new magnetic attachments have been tried in 70 clinial cases. The periodontal conditions, such as tooth mobility, gingival index and periodontal pocket depth, over 125 abutment teeth and the usefulness of the dentures with the attachments were investigated more than three months after the attachments had been installed.
As a result, the new attachment did not show any deteriorating effects on the abutment teeth and their periodontal structures. Most of the patients are satisfied with the favorable stability and function of the new dentures.
The magnetic attachments have been confirmed to be safe and reliable in the oral cavity and also to be useful equipment in retaining removable dentures.

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Recently, sports dentistry has attracted attention as a field of sportsmedicine. Since the stomatognathic system and the systemic condition closely affect with each other, we have studied both of them objectively, physiologically and scientifically.
Archery is a sport requiring static concentration of thought, and it seems to be extremely important for this sport to control a basic posture at the time of aiming at a target.
This study was carried out for the purpose of obtaining a fundamental data on how a bite raising for vertical position by a resin splint, which maintained stable occlusion, influenced gravity fluctuations in posture at the time of aiming at a target.

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Six soft lining materials have been examined (two acrylic, two silicone, one fluoric and one olefin materials) for their viscoelastic properties and surface deterioration caused by using peroxide denture cleansers. All tests have been done on 7.0 mm thickness disk specimens. The viscoelastic properties were investigated using a 10% compression strain and a 40 sec relaxation.
From the results, large difference appeared between the various lining materials.
1. The relaxation modulus of the acrylic lining materials was easily deteriorated by the denture cleanser compared with the other lining materials.
2. The cloudiness of the specimen surface and the variation of light reflectivity in the surface of the silicone and olefin lining materials became larger those of the fluoric lining material.
3. Ethanol added as a plasticizer was almost eluted within short period and furthermore the use of denture cleanser increased the elution rate of ethanol.

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The terminal position of mastication (centricocclusion: CO) has been reported to coincide with the intercuspal position (ICP), which is defined as the mandibular position where the maximum intercuspation occurs. However, the relationship between the ICP and the CO still remains unclear.
The purpose of this study is to investigate the relationship between the ICP and the CO.
Recording and analysis of the three-dimensional relationship between the ICP and the CO were performed in fourty subjects with normal occlusion, fifty subjects with abnormal occlusion, and sixty subjects with craniomandibular disorders by using the Sirognathograph Analyzing System.
As a result, the non-coincidence of the ICP and the CO was characteristically observed in subjects with abnormal occlusion and craniomandibular disorders.
From the results obtained, it is suggested that the terminal position of mastication does not always coincide with the ICP.

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Laminate veneer restorations were made for 40 patients with 202 teeth were restored. After recalling for prognosis evaluation (for the duration varied from six months to three years two months), the results were summarized as follows:
1. The examination of gingival soft tissue showed that 61 teeth (30.2%) were attached by plaque and 87 teeth (43.1%) had sign of gingivitis.
2. Marginal adaptation and surface condition of restorations were still good.
3. The color of restorations were evaluated “excellent” of “good” by both patients and dentists.
4. After setting the restorations, four patients (10%) felt sensitive to cold water, however, the symptom disappeared within one week.
5. Detachment and fracture occured to six teeth (3%) which were corrected by resetting or remaking if necessary.

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In the present study I examined conditions of dynamic extraction for cytotoxicity evaluation of metallic biomaterials. Specimens of Ni-Cr alloy, Co-Cr alloy and Ti of three shapes were extracted in glass vessels under dynamic conditions at 160, 200, or 240 rpm. Ni-Cr and Co-Cr alloy, but not Ti, specimens showed cytotoxicity, which varied with specimen shape and extraction conditions. Cylindrically shaped specimens showed greater dissolution of Ni, Cr and Co and greater cytotoxicity than spherical or plate-shaped specimens. Dissolution of the constituent elements and cytotoxicity also increased with extraction speed and duration. Furthermore, concurrent analysis of wear debris revealed that the extraction condition of 240 rpm for 7 or 14 days resulted in unexpected wear of the glass vessel and is therefore not appropriate for these base metals. The most efficient extraction condition for in vitro cytotoxicity evaluation of base metals was found to be that in which a cylindrically-shaped specimen is extracted at 240 rpm for 5 days. It is considered that the present results offer potential in validation of in vitro testing of metallic biomaterials.

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The purpose of this study was to investigate the validity of some rating scale methods to measure patients' satisfaction on prosthetic treatment with removable dentures. Each group of 102 Full denture weareres, 95 A-P denture weareres, and 106 P denture weareres was analyzed. Applying the quantification method of the third type, the characteristics of patients' satisfaction in each denture group was investigated on content and strength.
The following results were obtained.
1. The criteria for rating as dissatisfied, a little dissatisfied, mindless, satisfied, or very satisfied provided for each item were proper related to content of patients' satisfaction on Full denture, but not so on A-P and P denture.
2. The valid critetia of scales on content and strength were 3 grades rating as “dissatisfied or a little dissatisfied”, “mindless”, or “satisfied or very satisfied” on Full denture, “dissatisfied, a little dissatisfied, or mindless”, “satisfied”, or “very satisfied” on A-P denture. On P denture, these were 4 grades rating as “dissatisfied”, “a little dissatisfied or mindless”, “satisfied”, or “very satisfied”.
3. It is considered that the reliability of scores assingned to rating grades should have to be enhanced to measure content and strength of patients' satisfaction.

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Effects of the gingiva and pulp on natural teeth color were studied in order to determine the mechanism of crown coloring. Namely, teeth color was measured in 30 left maxillary central incisors of young subjects using a spectroradiometer under the following 4 different conditions:(1) free from artificial matters, (2) wearing of a masking plate, (3) undergoing infiltration anesthesia, and (4) simultaneous loading of (2) and (3).
The results obtained are as follows:
1. In the cervical area, the gingiva showed a greater effect than did the pulp.
2. In the middle area, the pulp showed a little effect, but the gingiva exercised practically no effect.
3. In the incisal area, neither gingiva nor pulp influenced teeth color.
4. These results revealed that the spectral radiance factor of a natural teeth increased as the wavelength increased, showing a characteristic inflection point at about 580 nm, and that the gingiva and pulp had different effects on crown coloring among different areas.

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In order to determine the relation between the craniofacial form during vertical clenching was measured in 11 men showing normal occlusion with natural dentition who were classified in a Short face group. The craniofacial function in the Short face group was compared with that in a Normal face group, and the effects of differences in the craniofacial form on the function were examined.
The results were as follows:
1. Correlation with 11 items of craniofacial measurement A significant correlation was found between θ and Ar-Go-Me, MP-OP, SN-MP, SN-OP or MM -OP and between θ' and SN-OP or MM-SN.
2. Comparison with Normal face groups
The results of t-test for difference between the Short face and Normal face groups with regard to the direction of bite force at each assigned magnitude of clenching showed that the direction was generally similar in the two groups, but that θ' was significantly greater in the Short face group at 25% and 50% MC.
The above findings indicate that the correlation between the direction of bite force (θ and θ') and some particular items of craniofacial measurement was closer in the Short face group than in the Normal face group. It is also apparent that the muscle played a leading role in conditioning the direction of bite during vertical clenching in the Short face group in comparison with the Normal face group.

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This study is to investigate the stress distribution in the peripheral bone tissue of blade type implant under various conditions using two-dimensional Finite Element Method (FEM) analysis and the following conclusions were obtained: 1) As the bending angle of the neck portion of the implant and the embedding inclination of implant into the bone structure increased, the generation of stress also increased. The bucco-lingual position of the superstructure increased as the bending angle and inclination of implant increased. 2) The maximum principal compressive stresses were observed at the bended neck portion and at the areas adjacent to the inclined side of the implant. 3) The estimated limit of the bucco-lingual position of the superstructure should be 2 mm (16.6 degrees when converted to bending angle) in consideration of the physiologic tolerance of bone tissue against compressive stress (2.55 kgf/mm²). 4) Compressive stresses concentrated at the cortical bone area in bone-contact condition and at the fibrous tissue area in fibrous tissue intermediating condition.

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In this study, tensile bond and three point flexural strength tests were performed to investigate the adhesive effect of Super-Bond and Panavia onto 0CC (Olympus Castable Ceramics) and SUS as substrate. As the conclusions, 1) Fluoric acid treatment of 0CC surface had little effect on tensile bond strength. 2) Adhesive strength improved when sand-blasted OCC was adhered with Super-Bond. Likewise, silane treatment combined with sand-blasting of OCC surface improved the adhesive strength when Panavia was used. 3) Maximum tensile strength was obtained with Super -Bond superior to Panavia when OCC surface was silane treated with the combination of sand -blasting. 4) From the results of three point flexural strength test with the OCC-adhesive resin -SUS 304 laminated specimen, maximum strength was obtained with Super-Bond superior to Panavia when OCC surface was sand blasted with alumina particles and the load was applied from OCC side. 5) On the contrary, maximum flexural strength was obtained with Panavia superior to Super-Bond when OCC surface was sand blasted with alumina particles and the load was applied from SUS 304 side.

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The jaw opening reflex was determined in 8 healthy subjects, 11 patients with craniomandibular disorder of type I and another 11 of type II, and the following results were obtained.
1. The degree of mouth opening was significantly lower in type I or type II than in healthy subjects, but no particular difference was found between type I and type II. It was passed judgment on normal (+) in healthy subjects, whereas decline (±) in type I or type II.
2. There was a correlation between the degree of mouth opening and the jaw opening and closing muscles.
3. The temporal muscle activity before stimulation (IBT) was significantly higher in type I than healthy subjects, but there was no particular difference between type II and healthy subjects. Type I and type II showed similar to IBT. The masseter muscle activity before stimulation (IBM) in type I and type II was similar to that in healthy subjects.
4. The temporal muscle activity after stimulation (IAT) and the masseter muscle activity after stimulation (IAM) was highest in type I, followed by type II and healthy subjects in order, with significant intergroup defferences.
5. The IAT/IBT ratio was highest in type I, followed by type II and healthy subjects in order, with significant intergroup difference. The IAM/IBM ratio was significantly higher in type I or type II than in healthy subject, but there was no particular difference between type I and type II.
6. The digastric muscle activity (ID) was significantly lower in type II than in type I or healthy subjects. The ID were similar in type I and healthy subjects.

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In construction of complete denture, the master cast should represent the contour of oral mucosal surface, with the basal soft tissue taken into account on the basis of anatomical understanding.
In this study, I took impressions of a simulation model of the maxillary edentulous ridge, using silicone rubber (SIL), polysulfide rubber (RUB) and alginate (ALG) as impression materials with impression tray having stoppers. The effects of the type of impression material, seating speed and holding pressure of impression tray on the contour of the master cast was investigated in terms of the profiles and displacement, and the following results were obtained.
1. The seating speed, with SIL indicated no effects in the space section and the stopper section. With RUB and ALG, there were no effects in the space section, but were evident effects in the stopper section.
2. The holding pressure, with SIL, RUB and ALG indicated no effects in the space section, evident effects in the stopper section.
3. A comparison of impression materials revealed that the displacement in the space section was largest for SIL: the other two materials showed similar degrees of displacement. In the stopper section, I found the order of SIL, RUB and ALG at the minimum holding pressure, and ALG, RUB and SIL at the maximum holding pressure, according to descending displacement.
Thus, SIL was found to be the most appropriate impression material for representing the contour of the mucosal surface of master cast of maxillary edentulous ridge.

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The relationship between craniomandibular morphology and 3-D movements of the mandible must be taken into consideration when the restorations are given and stomatognathic system examined. However, it has not been enough investigated.
In this paper, we focused on the dentocranial morphology and analyzed accurately the occlusal plane and the curve of Spee. Subjects consisted of sixty Japanese young adults with normal occlusion. Our results were summarized as follows.
There was significant difference between males and females on the angle of the occlusal plane inclination. Males' inclined to posterior and females' were nearly parallel to the reference plane for prosthodontics.
Our reference plane were more parellel to the occlusal plane than others. And the inclination of the occlusal plane significantly corelated to the vertical location of the lower incisor.
There was also significant sex differences both on depth and form of the curve of Spee. Females' curved more sharply than males' especially on the posterior teeth.
These results suggest that new reference plane is effective for bite taking and these sex differences give effects on the mandibular movements or other stomatognathic functions.

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This is a report on experiments in applying microwaves to denture resin polymerization of metallic denture. The aim of the experiments was to examine the temperature inside resin, the hardness of cured resin and the internal porosity when 3 mm and 4 mm thick resin was polymerized with metal plate and when polymerization was done with denture resin alone.
When microwaves at a power output 500 W were used to polymerize 3 mm thick resin, properly cured resin could be obtained if irradiation lasted from 1.5 to 5 (or 1.5 to 3) min. When microwaves at a power of 500 W were used to polymerize 4.5 mm thick denture resin, the range of irradiation time for obtaining properly cured resin tended to be narrower than in the case of 3 mm thick resin. This tendency was particularly noticeable when polymerization was done with metal plate. In this case the temperature inside the resin rose sharply with the polymerization of the metal plate. This also caused many internal porosity.
As a countermeasure to slow down the rise in temperature inside the denture resin at the time of polymerization, irradiation using 500 W microwaves was initially limited to one min. This was then followed by another 2 to 4 (or 3 to 5) min of microwave irradiation at a reduced power output of 200 W. A properly cured resin could be obtained under these conditions.

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The purpose of this study is to clarify the stability of the habitual lateral mandibular movement which is different from the border lateral movement. The movements of 30 normal subjects were measured dynamically and precisely with Kyushu University 3-D movement analizing system.
The following results were obtained:
The habitual incisal lateral movement was very stable from the intercuspal position to 3 mm lateral point.
The stability of the movement was not influenced by the occlusal factor such as the lateral guidance.
As a result, the movement was so stable and repeatable that it could be used as a reference movement for comparing with other movements.

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A photoelastic stress analysis technique has been conducted for many years as a test to predict the mechanical behaviors of porcelain teeth under a load. The purpose of this study was to investigate the stress distribution of a castable glass ceramics-porcelain jacket crown under a static load and obtain the some informations for producing the jacket crown. On the assumption that the jacket crown consist of two layers (castable glass ceramics coping and dental porcelain), the crown models were made of epoxy resin. Three different loading sites were chosen (lingual porcelain surface, lingual castable glass ceramics surface and incisal porcelain surface) to epoxy resin models.
In the case of the model which the load (2.0 kgf) was added to the lingual castable glass ceramics portion, the tensile stress in the labial porcelain portion reached the maximum value. And, when the same load was added to the lingual porcelain portion of the model, the tensile stress in the lingual castable glass ceramics portion reached the maximum value. Furthermore, in the model which was added to the lingual castable glass ceramics portion, the high tensile stress was observed in the lingual castable glass ceramics-porcelain border.

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Resilient denture lining materials have been known as one of the effective measures for treating cases with severely atrophic mandible or with constant pain on residual ridge. The effective method of application and the mode of action of these materials, however, have not been clearly demonstrated yet. The main objective of this study was to investigate the influence of these materials on occlusal force distribution using T-Scan system. The study was carried out on six volunteer edentulous manidble patients using resilient polyolefin lining materials with two different hardness (soft and hard).
Following results were obtained.
1. In dentures with the soft resilient lining material, comparing with the hard one or the conventional resin base, the number of occlusal contact points increased and the location of contacts more widely spread within dental arch.
2. Despite the use of soft lining material, pain and discomfort were not eliminated in some subjects. Orthopantomography of these subjects suggested the topography of mandibular bone cloud has significant effect on these incidences.
3. Occlusal adjustments should be carefully performed after the insertion of denture with soft lining material.

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A dental soldering technique called stand soldering method was studied in this paper by determining the displacement of three-unit fixed partial dentures.
The number of times to pre-heat the stand, the height of the pillar of the stand and the thermal expansion coefficient of the stand were investigated as possible main factors causing the displacement.
The conclusions obtained were as follows:
Pre-heating of the soldering stand should be done at least once. The pillars of the soldering stand should be designed as short as possible. The material of the soldering stand should be identical to that of the denture in terms of the thermal expansion coefficient.

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The rebuilding abutment teeth with the metal core is one of the most important procedures for the long-termmaintenance of the teeth which are due to treated with the crown prosthesis. Hitherto, dental cement, dental amalgam, metal casting, and the combined method with the readymade post and composite resin have been applied generally for the rebuilding abutment teeth. The rebuilding abutment teeth with the metal casting has been widely applied for a long time and had a good reputation clinically, while it has been improved for the clinical use. But, this method brings difficulties when applied for the divergent and multi-rooted teeth. Therefore, the split method has been used for the divergent and multirooted teeth, since it is difficult to insert the one piece casting dowel-core into the non-parallel root canals. Althougt this difficulty is originated from the divergence in the direction of the root canals, some techniques such as the application of carbon rods and of the investment materials have been designed to remove this problem. But, these method has not been accepted for the difficulty in the laboratory technique. This study was performed to improve the defects of these previous techniques. The results showed that the relatively precise fitness between the ready-made post and the post channels can be obtained by using the carbon rods, and that the combined technique with ready-made screw post can accomplished the primary object of this study.

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Bioactive glass has been known as a material which can directly bind to bone, and the application of it to the field of dental implants has been attempted. However, few investigations on the progress of bone formation around the bioactive glass in the jaw bone have been reported.
The purposes of this study were to examine the bone formation around bioactive glass, and to study the influences of the jaw bone condition on bone formation. Conditions of the jaw bone were determined according to the elapsed time between tooth extraction and implant insertion. The mandibular fourth premolars of 6 beagles were extracted, and implants were inserted into the same places at 4, 8, and 12 week intervals.
In all cases, after 2 weeks a layer of newly formed bone tissue of various maturation levels were found to be in direct contact with the bioactive glass. Furthermore, bone maturation was found to be more prominent after 8 weeks. This result may suggest that bioactive glass can bind to bone without much influence from the condition of the jaw bone.

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The purpose of this study was 1) to estimate the occlusal height reproduced by working models, 2) to investigate the dimensional accuracy of complete dental arch stone casts, and 3) to estimate the relationship between 1) and 2).
The working models were made from an epoxy reference model. The reference model did not have any biologic characteristics which affect the occlusal height of working models. The occlusal height was measured using an IP-Checker. The stone casts were made from a metallic model of a simplified maxillary dentition. The dimensional accuracy of the stone casts was measured using a three-dimensional measuring microscope.
The results were as follows:
1. The occlusal height reproduced by the working models was higher than the occlusal height of the reference model.
2. The difference of the occlusal height between the reference model and the working models made from silicone impression materials and the improved dental plaster was the smallest.
3. The stone casts made from the silicone impression materials and the improved dental plaster were the most accurate.
4. This study suggested that more accurate stone casts reproduced more accurate intercuspation.

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To study what kinds of sugar residues are involved in the specific adherence of Candida, several kinds of sugars were coverently bound to the glass slides either by coupling p-aminophenyl-o-glycosides or amino sugars to carboxyl methylene group of glyoxylic acid conjugated glass slides, and the adherence of Candida albicans andC. tropicalisto these immobilized sugars were measured.
C. albicansadhered to these glass slides with specific profiles, and the number of adherent cells were significantly higher to glass slides containing mannose-, mannosamine-, galactosamine-and fucose-residue than to control glass slides. TheC. albicansadherence to these sugar-immobilized glass was inhibited by the presence of monosaccharides with similar configuration to immobilized ones. These results, taken together, suggested that mannose^-, mannosamine^-, galactosamine- and fucose-residues are involved in the specific adherence ofC. albicansthrough lectinlike interaction.
In contrast, C. tropicalisshowed the specific adherence only to glass slides containing glucosamine.

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