パテとウォッシュの2段階印象材の精度に関する無作為化比較臨床試験

Randomized controlled clinical study on the accuracy of two-stage putty-and-wash impression materials.

抄録

目的:

歯科印象採得の精度は，クラウンや固定式部分床義歯の適合性に影響を及ぼす大きな要因の一つである．本研究の目的は，3種類のシリコーン材料と2段階のパテ・アンド・ウォッシュ法による3次元歯面および歯肉縁下歯面再現の精度を明らかにすることである．

PURPOSE: The accuracy of dental impression taking is one major factor influencing the fit of crowns and fixed partial dentures. The aim of this study was to determine the accuracy of three-dimensional (3-D) tooth surface and subgingival tooth surface reproduction using three different silicone materials and the two-stage putty-and-wash technique.

材料と方法:

24人のプロバンドから，Express STD Putty/Wash（3M ESPE），Optosil/XantoprenL（ヘレウス・クルザー），実験的超軽量ボディ/パテ材（3M ESPE）をランダムな順序で用いてそれぞれ3つの印象を採得した．予備印象は，パテと洗浄の2段階法の確立された手順に従い，削り取った．標準的な手順でマスターキャストを作製し，光学的にデジタル化した．3次元的な精度はコンピュータ支援手順で解析された．また，Express STD パテ・アンド・ウォッシュ印象材を基準として使用した．統計解析には線形モデルを使用した．

MATERIALS AND METHODS: From 24 probands, three impressions each were taken with Express STD Putty/Wash (3M ESPE), Optosil/Xantopren L (Heraeus Kulzer), and an experimental ultralight body/putty material (3M ESPE) in a randomized order. The preliminary impression was cut according to established procedures for the two-stage putty-and-wash technique. Master casts were manufactured with a standardized procedure and optically digitized. The 3-D accuracy was analyzed with a computer-aided procedure. The Express STD putty-and-wash impressions were used as a reference. Linear models were used for the statistical analysis.

結果:

3次元表面再現性を解析した結果，Optosil/Xantopren Lは27.0μm，-23.6μm，実験材料は26.5μm，-22.6μmの平均偏差が認められた．また，歯面（頬側/口腔側）が再現精度に大きく影響した．Optosil/Xantopren Lは，実験材料や参照材料と比較して，歯肉縁下歯面をより完全に再現していた．

RESULTS: Mean deviations of 27.0 microm and -23.6 microm were found for Optosil/Xantopren L and 26.5 microm and -22.6 microm for the experimental material when analyzing 3-D surface reproduction. The tooth surface (buccal/oral) significantly influenced the accuracy of the surface reproduction. Optosil/Xantopren L showed a more complete reproduction of the subgingival tooth surface than either the experimental or reference materials.

結論:

超軽量ウォッシュマテリアルを使用した場合，3次元歯面再現の精度および歯肉縁下歯面の再現性は，予備印象の切削手順が確立されている場合には，あまり影響を受けないことが示された．

CONCLUSION: The accuracy of the 3-D tooth surface reproduction as well as the reproduction of the subgingival tooth surface was not favorably influenced when the ultralight wash material was used with established cutting procedures for the preliminary impression.