Biomedical subjects

T Nokubi

Publications and source records attributed to T Nokubi.

At least 55 records · Page 3Linked to original sources

PubMed1989

[Simulation of bone resorption in denture patients using finite element analysis. 1. Application of optimization method].

The purpose of this study was to simulate the process of bone resorption under removable denture bases. Two dimensional finite element models were prepared for the frontal section of a maxillary complete denture with its supporting mucosa and bone in the first molar region. Simulations were performed with the optimization program which could proportionally move the nodal points according to the stress level difference between the actual and the reference stress level. By exerting loads on occlusal table of the model, the bone resorption progressed in the similar manner to reported clinical observations. The location and magnitude of the resorption were highly related to the location and direction of the loads.

Alveolar Bone Loss↗

PubMed1989

[Inference engines of expert systems for designing removable partial dentures].

The expert system for designing removable partial dentures has a great potentiality for clinical and educational use. The system sorts out several solutions for clinical problems with the aid of logic and data bases stored in the memory bank. The most important part of this system is the inference engine. Production system and frame system are often used as the inference engine. The purpose of this report was to compare different types of inference engine in practical situations. Following conclusion were obtained. 1) Since each type of inference engine has its own advantages and disadvantages, one has to select most suitable one for the purpose of the system. 2) One must select the inference engine type which will help potential user's understanding.

Denture Design↗

PubMed1989

[Clinical application of T-scan System. 1. Sensitivity and reproducibility and its application].

Analyzing occlusal contacts is significant for establishing the occlusal scheme as well as for the diagnosis on dysfunction of stomatognathic system. We tested a new occlusal contact analyzing device (T-Scan: Tekscan Inc. Boston, U.S.A.) for its sensitivity and reproducibility in relation to its clinical application. Following results were obtained. 1) As the modeling of dental arch of this system was not always correct, much care should be needed for identifying the contact location. 2) The minimum amount of load needed for displaying each five step occlusal force increased linear fashion (step 1: 250 g and step 5: 1750 g) when the sensor was vertically pressed on the intersection of force sensitive line. The minimum amount of force changed with the loading condition such as area and direction. Distortion of the sensor could lead the measurement error. 3) Since the time measurement data by this system were shorter than actual length of time and were measured over about 250 g load, light and early occlusal contacts could not be detected.

Dental Arch↗

PubMed1989

[Construction of data base for designing removable partial dentures. 1. Retainer and abutment selection].

In designing removable partial dentures (R.P.D.) for edentulous patients, variety of designs are selected with considering the condition of residual teeth, alveolar ridge, occlusion and other factors. We have been trying to develop the computer consultation system for designing R.P.D. (so called "expert system") to rationalize the processes of R.P.D. design. In developing and expanding this system, the construction and enlargement of the rulebase and database are indispensable. In this report, we analyzed R.P.D. designs in student's clinic ('83-'85), in order to find the logic for design (rulebase) and to construct databases. Following results were obtained. 1) Wire clasps were most frequently used in Kennedy classification I, II in maxilla. Double clasps were mostly used in Kennedy class I, II in mandible. Akers' clasps were mostly used in class III. 2) Canine, first and second premolar were more frequently selected for abutment than other teeth.

Denture Design↗

PubMed1989

[Application of occlusal splint for the patient with temporomandibular joint dysfunction. An application of silane coupling treatment: a case report].

The bite plane therapy has been one of the most useful treatment methods for patients with temporomandibular joint (TMJ) dysfunction. But the bite plane usually causes esthetic and articulation disturbances and it is occasionally difficult to use during mastication. The authors have fabricated a new type of bite plane, named occlusal splints, which covers each side of the premolars and molars. The occlusal splint was constructed by a hard-resin for the occlusal part and cast clasps for the retentive part and these parts were adhered after a pre-treatment of metal by the use of a silane coupling agent (Silicoater system). The patient was a 35 year-old man, with a chief complaint of left side reciprocal TMJ clicking. The anterior repositioning type of bite plane was applied for the treatment with the diagnosis of anterior disk displacement with reduction. But he complained of esthetic and articulation disturbances especially during working and eating. After four months we fabricated an occlusal splint that can be used for a long period of time. The patient was satisfied to use this occlusal splint and no symptoms of TMJ dysfunction were found with this appliance. It is suggested that the occlusal splint consisting of a hard-resin and cast clasps is a useful appliance especially for the purpose of use during working and eating, and for evaluating the properness of mandibular position.

Adult↗

PubMed1989

[Relationship between orofaciocranial morphologic factors and electromyographic activities of the masticatory muscles].

The purpose of this study is to evaluate the relationship between orofaciocranial morphologic and functional factors. The lateral cephalograms of 10 normal subjects were taken and traced. The authors divided cephalometric parameters into linear and angular measurements. Electromyographic (EMG) activities were recorded from bilateral anterior temporal and masseter muscles during tapping movement. Then the total muscle activity of both muscles, and the masseter muscle activity ratio in the total muscle activity were measured. The correlation coefficients between cephalometric measurements and EMG parameters were analyzed. The results of this study are as follows: 1) The total muscle activity revealed positive correlation with all the linear measurements. Especially, the total muscle activity significantly correlated with the size of mandible, such as Co-Go and Go-Me. 2) The total muscle activity showed a tendency to increase when the angles among SN plane, FH plane, maxillary base plane and mandibular border plane became small, and when S-N-A and S-N-B became large. 3) There was no correlation between masseter muscle activity ratio and cranial morphologic measurments. But masseter muscle activity ratio correlated with tooth position and anteroposterior inclination of the anterior teeth. These results suggest that the consideration of the relationship between orofaciocranial morphologic factors and EMG parameters is necessary for examining the masticatory muscle activity.

Cephalometry↗

PubMed1989

Clinical studies on marginal gingiva around the abutment tooth. 2. Gingival health around proximal surface area adjacent to edentulous space.

Sixty subjects (42 subjects with dentures and 18 subjects without dentures) participated in this study. Crevicular fluid flow (Periotron unit: CGF), gingival index (GI), plaque index (P1I) and probing depth (PD) of 209 marginal gingiva around the proximal surface area adjacent to the edentulous space of natural and crowned abutment teeth were measured to evaluate gingival health. The following results were obtained. 1. The GI, P1I and PD in the subjects with dentures were higher than those in the subjects without dentures. The GCF in the subjects with dentures was inclined to be higher when compared to that in the subjects without dentures. 2. In the subjects with dentures, the GCF, GI and PD of crowned teeth were higher than those of natural teeth. On the other hand, in the subjects without dentures, the GCF, GI and PD of crowned teeth were almost equal to those of natural teeth.

Adult↗

PubMed1988