TITLE:
Prospective Demand for Fixed and Removable Dentures for Elderly and Dependent Elderly People in Japan
LANGUAGE:
in English
AUTHORS:
O.Kanatani M, Miyakawa O, Hotta N*
INSTITUTE:
Division of Dental Biomaterial Science, Niigata Universtiy Graduate School of Medical and Dental Sciences.
* Department of Material and Chemical Engineering, Niigata University Faculty of Engineering.
JOURNAL:
Dentistry in Japan 39: 63-66, 2003
KEY WORDS: The elderly, Dependent elderly people, Home dental health care, Projection

ABSTRACT:
To help frame long-range plans for dental clinics, education and research on fixed partial dentures (bridges) and removable dentures in Japan, this study estimated the prospective demand for the two prostheses. The subjects were Japanese people of 65 and above, and the dependent elderly. The per capita numbers of the prostheses were extrapolated by regression analysis based on survey reports of dental diseases. Some regression lines were corrected so that mutual intersection would not occur between age groups and the estimated value would not exceed each upper limit. The numbers of the prostheses were calculated by multiplying the estimated average numbers and projected populations together.
It was estimated that prospective demand for fixed partial dentures for the elderly would increase 2.0 times (2.2-1.1 with 95% confidence interval) in 20 years, that for removable dentures 1.5 times (1.8-1.0), and both would reach each a plateau during the subsequent 10 years. The prospective demand for fixed partial dentures for dependent elderly people was also estimated to increase 2.7 times (3.2-1.0) in 25 years, and that for removable dentures 1.8 times (2.2-1.0). Therefore, we are faced with the importance of dental clinics, education and research on prostheses for the elderly and dependent elderly people.

 

TITLE:
Number Projections of Bridges and Dentures for Elderly and Dependent Elderly People
LANGUAGE:
in JAPANESE with English Abstract
AUTHORS:
Kanatani,M., Watanabe,K., and Miyakawa,O.
INSTITUTE:
Department of Dental Materials and Technology, Faculty of Dentistry, Niigata University
JOURNAL:
The Journal of the Japan Prosthodontic Society 45:227-237, 2001
ABSTRACT:
Purpose. To help frame long-range Programs for education, research, and clinics on bridges and dentures, we estimated the numbers of these prosthetic appliances that will be needed in the future.
Methods. People of age 65 and above, including dependent elderly, were investigated. The average numbers of these appliances per person were estimated by regression analysis based on survey reports of dental diseases. Several regression lines were corrected so that mutual intersections would not occur between age groups and the estimated value would not exceed each upper limit. The total numbers of these appliances in the future were calculated from the estimated average numbers and population projections.
Results. It was projected that the numbers of bridges and dentures used by the elderly would increase 2.0 times (2.2-1.1 times, by 95% confidence interval) and 1.5 times (1.8-1.0 times) in 20 years, respectively, and plateau during the subsequent 10 years. The older the age group was, the higher these rates of increase would become. The numbers of bridges and dentures for dependent elderly people were also estimated to increase 2.7 times (3.2-1.0 times) and 1.8 times (2.2-1.0 times) in 25 years, respectively.
Conclusions: We will be faced with the importance of dental education, research, and clinics on bridges and dentures for the elderly and dependent elderly people.

Key words
the elderly, dependent elderly people, people with disabilities, home dental health care, projection

 

TITLE:
Partial Deformation of the Casting and Castability on Double Casting Method Using Gold Alloy
LANGUAGE:
in JAPANESE with English Abstract
AUTHORS:
Kanatani,M., N.Hotta,N., and S.Kohno,S.

INSTITUTE:

JOURNAL:

The Journal of the Japan Prosthodontic Society 42: 271-278, 1998
ABSTRACT:
Abstract. Double casting method (cast on technique) is sometimes used for attachment work. As to this method, the present study was conducted to investigate the partial deformation of casting and the castability of the second casting. A wax sheet stuck on the first cast plate of a gold alloy was invested with a gypsum-bonded investment. Using a centrifugal casting machine, two kinds of alloy were cast in the mold heated to 700°C, one was the same alloy as the first casting and the other was a silver-palladium-gold alloy.
Protuberances on the first casting and the corresponding concaves on the second casting were found approximately beneath the sprue. Some protuberances appeared to be wavy, while the others appeared to be hemispherical, with a maximum height of 220 mm. There were no differences in the size and shape of crystal grain as well as the composition between the protuberance and the body of the first casting. Therefore, the protuberances did not result from the adhesion of the molten metal to the first casting, but from the partial deformation of the first casting. In case of using a silver-palladium-gold alloy for the second casting, some of the first castings had concavities.
The castability of the second casting was significantly low, compared with general casting.

Key words. cast on technique, deformation, protuberance, gold alloy, castability

 

TITLE:
Experimental Study on the Anterior-Posterior Distribution of Bite Force as Measured by Dental Prescale --Investigation from Contact Force Distribution on an Experimental Model--
LANGUAGE:
in JAPANESE with English Abstract
AUTHORS:
Nomura,S., Kanatani,M., Kohno,S., Kamo,G., Nakano,S. and Miyakawa,M.
INSTITUTE:

JOURNAL:
The Journal of the Japan Prosthodontic Society 41: 710-718, 1997
ABSTRACT:
Abstract . Bite force measurement on intercuspal clenching in normal subjects using the pressure sensitive sheet "Dental Prescale" showed that larger bite forces were applied to the posterior teeth than to the anterior teeth. In this study, an experimental model revealed that the even thickness of the pressure sensitive sheet was one of the influential factors in this characteristic distribution.
The experimental model consisted of 14 steel ball-bearings, used as substitutes for the dentition, and a glass slab which were respectively mounted in the maxillary and mandibular elements of a semiadjustable articulator. Three kinds of loading conditions were determined and applied to the upper member with an
Instron-type testing machine, then contact forces were compared with the Occluzer FPD 703. Firstly, the upper member was removed from the articulator and the pressure sensitive sheet was loaded directly. Secondly, the condylar elements of the articulator were locked through centric latches, and thirdly, the condylar elements were not locked.
The direct load distributed contact forces almost equally to each steel ball. On the contrary, the load with locked condylar balls distributed larger contact forces to the posterior steel ball-bearings than to the anterior ones. However, the unlocked load showed a similar distribution to the direct load.

Key words . pressure sensitive sheet, bite force distribution, experimental model, Dental Prescale, thickness

 

TITLE:
Synthesis and Sintering Behavior of AlN/YN Composite Powders by Floating-type Fluidized-bed CVD
LANGUAGE:
in JAPANESE with English Abstract
AUTHORS:
Fukui,K., Firukawa,Y., Kotera,K., Tawaragi,K., Kanatani,M. and Hotta,N.
INSTITUTE:

JOURNAL:
J the Materials Science Soc of Japan 34:281-287, 1997
ABSTRACT:
Fine AlN/YN composite powders were synthesized at 1823K by the floating-type fluidized-bed CVD. Al powder was continuously supplied by N2 gas introduced from the bottom of a reactor and nitrided. Gaseous YCl3 evolved at temperatures between 1173K and 1773K was converted into YN in a gas flow consisting of N2 and NH3. The primary particles were very fine and the sizes of AlN and YN were 0.1-0.2 mm and 12nm, respectively. The YN composition in the composite powders could be controlled in the range 0.4 to 2.7 wt% by elevating vaporization temperature from 1173 to 1773K. The sinterability of the composite powders synthesized in this study is so excellent that high thermal conductive AIN ceramic with 190 W/mK could be prepared at a sintering temperature of 2173K. YN synthesized in the reactor of the floating-type fluidized-bed CVD was confirmed to play an important role as a sintering aid as well as Y2O3.