Biomedical subjects

S Minakuchi

Publications and source records attributed to S Minakuchi.

14 recordsLinked to original sources

PubMed2000

Measuring system for lip movements using two video trackers.

Movements of soft tissues surrounding the oral cavity, especially lips and cheeks, have a strong influence on mastication and phonetics. They also influence the relationship between a denture and its oral environment. The purpose of this study was to develop a three-dimensional measuring system for soft tissue movement. This system consisted of two video trackers placed stereographically and a computer. In addition, one video tracker was connected for measuring mandibular movements. The accuracy of this system was evaluated using computerized XYZ pulse stage. The resolution of this system was 0.10 x 0.10 x 0.10 mm, when the measurement was carried out in the area of the 24.0 (X) x 20.0 (Y) x 20.0 (Z) mm with a working distance of 500 mm and a frequency of 120 Hz. In the present study, the lip movements of a dentulous subject with mandibular movements during chewing peanuts were analysed using this system. The new system demonstrated its value for analysing soft tissue movement.

Adult↗

PubMed1998

Denture mobility with six degrees of freedom during function.

The purpose of this study was (1) to assemble and verify a system to measure the three-dimensional (3-D) movement of the upper and lower complete dentures and the movement of the mandible simultaneously, and (2) to analyse the relation between denture movements and the path of closure of the mandible during function. A 3-D motion capture system with four infrared TV cameras was used for this purpose. The relation between the dentures and the mandibular movements was analysed through the change of the inner product of normal vectors of the denture occlusal planes and mandibular planes. The mandibular movements were classified into two types; the normal stroke (the path of closure was on the ipsilateral side of mastication) and the reverse stroke (on the contralateral side). The results showed that the system could measure the denture mobility within a 0.3 mm error. The mobility of the upper dentures had a correlation to the path of closure of the mandible regardless of the working side or nonworking side, and the lower dentures had a tendency to move toward the working side.

Aged↗

PubMed1997

Effect of mastication on regional cerebral blood flow in humans examined by positron-emission tomography with ¹⁵O-labelled water and magnetic resonance imaging.

The interaction between mastication and cerebral blood flow was studied in 12 healthy volunteers (five males and seven females) aged 18-40 years. Positron-emission tomography (PET) autoradiography was carried out after bolus injection of 1.5 GBq H₂¹⁵O (¹⁵O-labelled water) with a half life of 2 min. The PET images were superimposed on magnetic resonance images of each participant. The regional cerebral blood flow images were normalized by the global cerebral blood flow value, and subtraction images (those during gum-chewing minus those during resting) were created and recut at the magnetic resonance image slice positions. Gum specially designed for chewing training was used. Mastication increased regional cerebral blood flow in the primary sensorimotor areas by 25-28%, in the supplementary motor areas and insulae by 9-17%, and in the cerebellum and striatum by 8-11%. These increases demonstrate that chewing activates widespread regions of the brain.

Adolescent↗

PubMed1994

[Clinical evaluation of measuring system of occlusal force].

An occlusal diagnostic system was evaluated for clinical applications. This system consists of pressure sensitive sheets (DENTAL PRESCALE, Fuji Photo Film Co.) and analyzing computer (OCCLUZER FPD703, Fuji Photo Film Co.). The clinical efficiency of this system was evaluated in aged dentates, aged complete denture wearers and an aged patient suffered from periodontitis. The results were as follows: 1. There was a positive correlation between the masticatory efficiency and maximum occlusal force. 2. In the complete denture wearers, the distances from the medial line to the center of the occlusal load were statistically greater in the adjustment needed cases than in the control group. 3. In a case of periodontitis, the full arch fixed splint was adjusted using this system. After adjustment, the maximum occlusal force and contact area increased, and the maximum and medial pressure of the occlusal contact force decreased. 4. It was suggested that this system would be available for the examination of masticatory efficiency and diagnosis of various types of occlusions.

Aged↗

PubMed1993

[Epidemiological study on distribution of plaque, calculus and gingivitis among Nigerian people].

In 1991, dental health examination was carried out in Nigeria: ILE-IFE (urban) and Ashipa (rural) located in the southwest of Nigeria. The number of the subjects was 205 (aged 8, 10, 12) in ILE-IFE and 511 (aged 8, 10, 12, 15 to 75) in Ashipa. The purpose of this study is to clarify the distribution of plaque, calculus and gingivitis and to reveal the correlation between the plaque score (DI-S, OHI-S), calculus score (CI-S, OHI-S) and gingivitis score (GI) among the Nigerian by age. Results were as follows: 1. In the comparison between urban and rural schoolchildren, CI-S was higher in the rural children statistically but DI-S was not. This evidence is to be expected as a consequence of using PACO (traditional twig) for tooth brushing, because 73.1% of rural children were using the PACO whilst 92.1% of urban children were using the tooth-brush. 2. Because of the poor oral cleanliness using PACO, the changing pattern of DI-S, CI-S and GI by age could be natural and physiological. 3. DI-S and CI-S among the rural people were of a high level in the children 8 and 10 years of age and decreased to the bottom level in the 20's. After the lowest scores in the 20's, these increased with age. 4. The correlations between DI-S and GI were higher in the young people than in the elder people.

Adolescent↗

PubMed1993

Joint epidemiological longitudinal dental survey in Nigeria, especially in comparison with that of Japanese.

Since 1980 we carried out a longitudinal dental survey in Ile-Ife, as a joint study with the dental school of Ife University, Nigeria, being supported by A Grant under The Monbusho International Scientific Research Program for ten years. One thousand one hundred seventy-one children and adults were examined in the 1991 survey. The data were compared with the data in the previous survey and Japanese survey. Results were as follows: 1) Caries prevalence rate and the average number of DMFT were still very low, especially showing that both the caries prevalence and the average number of DMFT decreased in the rural areas because the attrition proceeded faster than the caries, 2) Nigerian deciduous and permanent dentition were larger than in the Japanese in all items measured, 3) the condylar head was transformed from the round shape to the ultra-flat shape with age, 4) there was a fewer incidence of severe periodontal diseases despite of the marked deposition of calculus, 5) with respect to Nigerian foods, there was no difference between the rainy and dry seasons in both the urban and rural communities, 6) the weaning period of the baby is decided by their mother, taking care of the health of the baby, almost all babies at one year to two years and a few at three years and 7) the menu for the breakfast, lunch and supper of the baby was made considering the nutritional aspect of the baby.

Adolescent↗

PubMed1987