Masami Yonemitsu

A Comparative Study of Oral State Schoolchildren between 1968 and 1979 in Minamidaito Island (Okinawa Prefecture)

Minamidaito Island is a rural village and it is difficult for the villagers to have a chance to receive dental treatment because of transportation difficulty.So the Department of Health of the Okinawa prefecture and eight dental shcools in Japan proper work in close cooperation to provide dental treatment using mobile units to the people of the islands in Okinawa. We compared the oral state of the schoolchildren in 1979 with that in 1968 when the staff of the dental mobile units visited the Minamidaito Island for the first time and found the following findings:1) No marked difference was found in the prevalence of DMF.2) Decayed tooth rate was decreased and the filled tooth rate was increased in 1979.3) The number of schoolchildren who answered “I have a toothache now” was decreased remarkably in 1979 compared with eleven years ago, and this was supposed to be the result of 2) .4) We feel keenly that primary prevention was needed in the isolated islands where dental care was difficult to receive like in the Minamidaito Island.

The Study on Oral Hygiene and Periodontal Pocket Formation of the Patients Visited the Department of Preventive Dentistry, Tokyo Medical and Dental University Hospital

本学予防歯科外来患者 (成人385名) について, 口腔内不潔度と歯周ポケットの関係を検討し, 下記のような知見を得た。I不潔度について1.男性の方が女性より不潔度が大きい。2.各歯種とも舌側の方が頬側より不潔度陽性率が大きかった。3.上顎では, 第二大臼歯が最も大きい不潔度陽性率の値を示し, 次いで第一大臼歯の順であるが, 下顎では中切歯が第二大臼歯に次いで大きい値を示した。4.上顎の同名歯を比較すると, 犬歯, 第一小臼歯では右の方が左より有意に高い不潔陽性率を示した。II歯周ポケットについて1.歯周ポケット陽性率は, 第二大臼歯で最も高い値を示し, 前歯部では低い値を示した。2.上下顎の同名歯の比較では, 上顎の方が高い歯周ポケット陽性率を示した。III不潔度と歯周ポケットとの関連性を歯種別に検討した結果, 28歯中16歯では5%危険率で関連が深いと考えられた。また上顎臼歯部は, その関連性が強い部位であると考えられた。

Ecological study of the area under a calculus splint

The bacterial population in the dentogingival area under a calculus splint was examined.Streptococcus salivarius with urease activity decreased and granular organisms (A. viscosus) increased significantly.The dry weight of the deposition decreased significantly.There was no viable count of cariogenic bacteria, Streptococcus mutans either before or after wearing the calculus splint.Therefore, although the glicolitic bacteria increased when the calculus splint was worn and the local PHdecreased, there is no fear of suffering from dental caries.The ratio of Streptococcus mutans to total Streptococcus was measured at various times after a 10% glucose rinse.Streptococcus mutans could be counted only rarely on the labio-lingual surface of the anterior teeth, but in the pits and fissures of the molars, the maximum ratio was measured between 5 and 15 minutes after rinsing after 30 minutes there was a sharp decrease and after 60 minutes the ratio was gradually returning to the initial ratio.