歯科用コバルトクロム鋳造体の表面粗さと精度に及ぼす研磨方法の違いによる影響

[Effect of different dental polishing methods on cobalt-chromium casts surface roughness and accuracy].

抄録

目的:

コバルトクロム鋳造体の表面粗さと精度に及ぼす研磨方法の違いを評価すること。

PURPOSE: To evaluate the effect of different polishing methods on surface roughness and accuracy of cobalt-chromium castings.

方法:

遠心バレル研磨、電解光沢研磨、研削、研削+遠心バレル研磨、研削+電解光沢研磨の5種類の研磨方法を比較した。30個の試験片（30 mm x 10 mm x l.5 mm）を6群に分け、鋳造および研磨して表面粗さ試験を行った。30個の上部総義歯床を鋳造し，6群に分け，それぞれ研磨前と研磨後の5ヶ所における上部総義歯後縁と模型との寸法精度を移動顕微鏡測定法により測定した．統計解析にはSPSS13.0を用いた一元配置分散分析を用いた．

METHODS: Five polishing methods were compared: centrifugal barrel polishing, electrical brightening, grinding, grinding+centrifugal barrel polishing and grinding+electrical brightening. 30 specimens (30 mmx 10 mm x l.5 mm) were divided into 6 groups which were cast and polished for surface roughness test.30 upper complete denture bases were cast and divided into 6 groups. The dimensional accuracy between the posterior border of the upper complete denture and model at five different positions were determined by traveling microscope measuring method respectively before and after polishing. One-way ANOVA with SPSS13.0 was used for statistical analysis.

結果:

研磨＋遠心バレルで研磨した試料は、研磨前のRa3.38μmに比べ、Ra0.19μmと最も平滑な表面であった（P＜0.01）。鋳造ベースと模型の後縁隙間に有意差は認められなかった（P > 0.05）。

RESULTS: Specimens polished by grinding+centrifugal barrel got the smoothest surface (P < 0.01) with Ra0.19 microm, compared with Ra3.38 microm before polishing. No significant difference of the posterior border gaps between the cast base and model was found (P > 0.05).

結論:

研磨＋遠心バレルにより研磨されたベースは、最も表面が平滑であった。遠心バレル研磨は、鋳造上台の寸法精度に影響を与えない。

CONCLUSIONS: Bases polished by grinding + centrifugal barrel had the smoothest surface. There is no influence of centrifugal barrel polishing on dimensional accuracy of cast upper base.