Johnson Glen H, Lepe Xavier, Aw Tar Chee
Department of Restorative Dentistry, Box 357456, University of Washington, Seattle, WA 98195-7456, USA.
J Prosthet Dent. 2003 Oct;90(4):354-64. doi: 10.1016/s0022-3913(03)00429-3.
Monophase and dual-viscosity impression techniques are available with little knowledge of which one might render better quality under wet and dry surface conditions.
The purpose of this study was to determine whether type of material, viscosity selection, and presence of moisture affect detail reproduction of elastomeric impressions.
Single-viscosity systems were polyether (Impregum Penta) and vinyl polysiloxanes (President MonoBody, Extrude MPV, and Aquasil). Dual-viscosity systems included polyether (Impregum Penta/Permadyne Garant) and vinyl polysiloxanes (Dimension Penta H/Dimension Garant L, Extrude Extra/Extrude Wash, and Aquasil/Aquasil LV). Impressions were made of a surface analyzer calibration standard possessing a uniform "saw-tooth" pattern with a mean roughness (Ra) of 2.87 mum, which was one fourth of the peak-to-valley height. Each of the 8 impression groups was subjected to dry (control) and wet conditions. The wet condition consisted of 3 mL of distilled water applied to the surface of the standard but allowed to escape during the procedure. Eighty impressions were made, 5 for each test group. After setting, the surface of each impression was scanned at 5 locations using a Surfanalyzer 4000. A 3-factor ANOVA and Student-Newman-Kuels test were used to analyze the data (alpha=.05).
There were significant differences between polyether and vinyl polysiloxane materials, dual and monophase techniques, and the 2 surface conditions (P<.05). Cross-product interactions were not significant, allowing comparison of mean values for each factor. The mean Ra for single viscosity was 2.21 mum versus 1.67 mum for dual viscosity; polyether was 2.12 mum versus 1.89 mum for addition silicone; and under dry conditions, the mean was 2.04 mum versus 1.86 mum for wet conditions.
Single-viscosity systems reproduced the standard saw-tooth pattern better than the dual-viscosity systems, as did polyether impression materials compared to addition silicones. Moisture led to a lower Ra or less detail compared to dry conditions.
有单相和双粘度印模技术，但对于在湿润和干燥表面条件下哪种技术能提供更好的质量了解甚少。
本研究的目的是确定材料类型、粘度选择和湿度是否会影响弹性体印模的细节再现。
单粘度系统包括聚醚（Impregum Penta）和乙烯基聚硅氧烷（President MonoBody、Extrude MPV和Aquasil）。双粘度系统包括聚醚（Impregum Penta/Permadyne Garant）和乙烯基聚硅氧烷（Dimension Penta H/Dimension Garant L、Extrude Extra/Extrude Wash和Aquasil/Aquasil LV）。印模采用表面分析仪校准标准件制作，其具有均匀的“锯齿”图案，平均粗糙度（Ra）为2.87μm，为峰谷高度的四分之一。8个印模组中的每一组都经历干燥（对照）和湿润条件。湿润条件是向标准件表面施加3mL蒸馏水，但在操作过程中使其逸出。共制作了80个印模，每个测试组5个。凝固后，使用Surfanalyzer 4000在每个印模的5个位置扫描表面。采用三因素方差分析和Student-Newman-Kuels检验分析数据（α = 0.05）。
聚醚和乙烯基聚硅氧烷材料、双相和单相技术以及两种表面条件之间存在显著差异（P < 0.05）。交叉乘积交互作用不显著，允许比较各因素的平均值。单粘度的平均Ra为2.21μm，双粘度为1.67μm；聚醚为2.12μm，加成型硅酮为1.89μm；在干燥条件下，平均值为2.04μm，湿润条件下为1.86μm。
单粘度系统比双粘度系统能更好地再现标准锯齿图案，聚醚印模材料比加成型硅酮也是如此。与干燥条件相比，湿度导致较低的Ra或较少的细节。
