Johnson A, Winstanley R B
Department of Restorative Dentistry, School of Clinical Dentistry, University of Sheffield, England.
Int J Prosthodont. 1994 Jan-Feb;7(1):35-42.
The effect of five dental investing techniques, three angles formed between adjoining internal pattern surfaces, and the use of a surface tension-reducing agent on air-bubble entrapment during investing were assessed. One investing technique, which mechanically mixed the investment under vacuum, invested the pattern without vacuum, then subjected the setting investment to .275 mPa of air pressure, was found to produce significantly fewer air bubbles than the other four techniques (P = 0.0096, Student's t test). The volume of the air bubbles was not found to be significantly affected by the different investing techniques, but the angle between adjoining internal pattern surfaces indicated that the more acute the angle, the larger the volume of the trapped air bubbles. When a surface tension reducer was used on the surface of patterns, pattern angles of 90 degrees had fewer trapped air bubbles than those produced with more acute tooth preparation angles, but the surface tension reducer agent had no significant effect on bubble volume. The use of a surface tension-reducing agent on the pattern surface prior to investing significantly reduced air bubble numbers (P = .054).
评估了五种牙科包埋技术、相邻内部模型表面之间形成的三个角度以及在包埋过程中使用表面张力降低剂对气泡截留的影响。一种包埋技术，即在真空下机械混合包埋材料，然后在无真空的情况下包埋模型，接着对凝固的包埋材料施加0.275毫帕的气压，结果发现该技术产生的气泡明显少于其他四种技术（P = 0.0096，学生t检验）。未发现不同包埋技术对气泡体积有显著影响，但相邻内部模型表面之间的角度表明，角度越尖锐，截留的气泡体积越大。当在模型表面使用表面张力降低剂时，90度的模型角度比制备角度更尖锐时截留的气泡更少，但表面张力降低剂对气泡体积没有显著影响。在包埋前在模型表面使用表面张力降低剂可显著减少气泡数量（P = 0.054）。
