Lepe X, Johnson G H, Berg J C, Aw T C
Department of Restorative Dentistry, University of Washington, Seattle 98195-7456, USA.
J Prosthet Dent. 1998 May;79(5):495-502. doi: 10.1016/s0022-3913(98)70168-4.
Previous studies have shown a relationship between the disinfection process, wettability, and mass change of impression materials. Hand-mixed high viscosity impression materials usually result in a material with numerous voids, which contribute to surface roughness and affect the surface characteristics of the material.
This study evaluated the effect of mixing technique on advancing contact angle, receding contact angle, imbibition, and mass loss of various high and low viscosity polyether and polyvinyl siloxane materials. The null hypothesis tested was no differences exist between the different mixing systems.
The Wilhelmy technique was used for deriving wetting properties of the materials used (Impregum F and Penta, Permadyne Syringe, Garant and Penta, Dimension Penta and Garant L, Aquasil). Conditions included no disinfection (0 hours) and 1, 5, and 18 hours of immersion disinfection in a full-strength solution of 2% acid glutaraldehyde disinfectant (Banicide). Weight changes before and after disinfection were measured to detect weight loss or mass increase over time. Weight loss in air was also measured to detect mass loss. Data were analyzed with a one-way analysis of variance at alpha = 0.05.
All materials displayed some degree of imbibition of the disinfectant and experienced mass loss with polymerization, except the light viscosity polyvinyl that gained 0.18% at 5 hours. No significant differences were found in wettability among the polyether materials after 1 hour of disinfection. Less imbibition was observed for high viscosity mechanically mixed materials compared with the hand-mixed materials for both polyether and polyvinyl siloxane at 1-hour disinfection time.
Polyether materials were more wettable than polyvinyl. Imbibition of high viscosity polyether and polyvinyl materials after 1 and 18 hours of disinfection were affected by the mixing system used.
以往的研究表明，消毒过程、润湿性和印模材料的质量变化之间存在关联。手工混合的高粘度印模材料通常会导致材料出现大量孔隙，这会导致表面粗糙度增加并影响材料的表面特性。
本研究评估了混合技术对各种高粘度和低粘度聚醚及聚乙烯基硅氧烷材料的前进接触角、后退接触角、吸液性和质量损失的影响。所检验的无效假设是不同混合系统之间不存在差异。
采用威廉米技术来测定所用材料（Impregum F和Penta、Permadyne注射器装材料、Garant和Penta、Dimension Penta和Garant L、Aquasil）的润湿性。条件包括不消毒（0小时）以及在2%酸性戊二醛消毒剂（Banicide）的原液中浸泡消毒1、5和18小时。测量消毒前后的重量变化以检测随时间的重量损失或质量增加。还测量了空气中的重量损失以检测质量损失。数据采用α = 0.05的单向方差分析进行分析。
所有材料都表现出一定程度的消毒剂吸液性，并且随着聚合会出现质量损失，但低粘度聚乙烯基材料在5小时时质量增加了0.18%。消毒1小时后，聚醚材料之间的润湿性没有显著差异。在消毒1小时时，对于聚醚和聚乙烯基硅氧烷材料，与手工混合材料相比，高粘度机械混合材料的吸液性更低。
聚醚材料比聚乙烯基材料更具润湿性。消毒1小时和18小时后，高粘度聚醚和聚乙烯基材料的吸液性受所用混合系统的影响。
