FUJIMURA Tetsuyuki Fukuoka Dental College, Assistant, 歯学部, 助手 (70269033)
KANEKO Noriaki Fukuoka Dental College, Lecturer, 歯学部, 講師 (70185932)
木村 重信 福岡歯科大学, 歯学部, 講師 (10177917)
原賀 義昭 福岡歯科大学, 歯学部, 講師 (10105702)
|Budget Amount *help
¥1,800,000 (Direct Cost : ¥1,800,000)
Fiscal Year 1994 : ¥600,000 (Direct Cost : ¥600,000)
Fiscal Year 1993 : ¥1,200,000 (Direct Cost : ¥1,200,000)
The scaler blade is abraded by repeated scaling. With abrasion, larger force is needed for scaling, causing more damage to the dental and root surfaces. To improve the abrasive resistance of scalers, we have produced scalers by vacuum evaporation with titanium ion plates or electrodeposition with diamond particles, and have evaluated the abrasive resistance of the scaler blade using an automatic scaling apparatus. For further improvement in the abrasion resistance of scalers, we experimentally produced scalers by surface reinforcing heat treatment, which is mainly used in the industrial field to reinforce the surface layr of steel and stainless products and increase the fatigue limit. Commercially available scalers after quenching and tempering were treated by nitriding, which is a surface reinforcing heat treatment method classified as gas soft nitriding. In this study, the cutting efficiency was compared between this scaler after nitriding and the conventional scaler or the diamond electrodeposited scaler that previously showed excellent abrasive resistance. In addition, 3 types of scalers obtained by nitriding with changes in the heat treatment time were compared.
Abrasive resistance measured using an automatic sclaing apparatus was higher for the S.T.scaler than for the other two scalers (N.T.and Di.). The cut amount decreased markedly after 1,000 strokes using the N.T.scaler and after 4,000 strokes using the Di.scaler. However, the cut amount was adequate even after 5,000 strokes using the S.T.scaler. These results suggested high abrasive resistance of the S.T.scaler.
Comparison of the 3 S.T.scalers (S.T.30,60, and 90) produced with changes in the heat treatment time showed no marked differences in the cut amount. This finding suggests negligible effects of the thickness of the nitridinng layr on abrasive resistance.