香港居住中国人幼児の乳歯列の咬合および形態に関する研究
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概要
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The aim of this study is to grasp the oral traits of deciduous dental arches in Chinese children in Hong Kong. Plaster models were taken from 277 children aged 5-year-old, 165 boys and 112 girls. Observations and measurements were carried out on these models. Sixty-six percent of the boys have normal occlusion and this value was slightly lower than that of the girls (73.2%). In types of malocclusion, upper protrusion was most frequent (11.9%) in both boys and girls, followed in order by anterior cross bite (7.6%), edge to edge bite (4.7%), over bite (4.0%), open bite (2.5%), and cross bite (0.4%). Results for boys and girls were similar, except for anterior cross bite which was significantly higher (p<0.05) in the boys. Combined primate space and developmental space type was most frequently observed in both boys and girls. The value of this type was 72.7% in the boys and 67.9% in the girls in upper jaw, and was 65.5% and 51.8%, respectively, in lower jaw. In both boys and girls, frequency of only developmental space in upper jaw and only primate space in lower jaw was lowest. In lower jaw, the boys having both primate space and developmental space were significantly more (p<0.05) than the girls. The percentage of children having bilateral vertical type of terminal plane was highest, 58.8% in the boys and 66.1% in the girls, followed in order by bilateral mesial step type, bilateral distal step type, vertical-mesial step type, and vertical-distal step type. No one had mesial-distal step type. There were no significant differences between boys and girls in each type of terminal plane. Both upper and lower anterior dental arch lengths were similar between the boys and the girls. Posterior dental arch lengths of the boys were 22.79 mm and 19.46 mm in upper and lower jaw, respectively, and were significantly longer (p<0.05) than those of the girls (22.39 mm in upper and 19.08 mm in lower). The dental arch breadth measurements, in all aspects, were significantly greater (p<0.01) in boys than in girls. All the indices, excluding lower anterior-posterior dental arch length index and anterior dental arch index, tended to be higher in girls than in boys. Especially, significant differences (p<0.05) were observed in upper anterior-posterior dental arch length index and upper anterior dental arch index. When compared with Taiwan Chinese and Okinawa Japanese, the length of dental arch in Hong Kong Chinese was longer than that in Taiwan Chinese, but shorter than that in Okinawa Japanese. And the breadth of Hong Kong Chinese was smaller than that in Taiwan Chinese, and smaller in anterior region than but similar in posterior region to that in Okinawa Japanese. In conclusion, when the characteristics observed and the values measured were compared among these populations and combined with the results of dental arch indices, the oral traits of Hong Kong Chinese were close to those of Taiwan Chinese.
- 九州歯科学会の論文
- 1992-10-25