Reddy G Vivekananda, Reddy N Simhachalam, Itttigi Jayaprkash, Jagadeesh K N
Department of Prosthodontics, Dr SM Naqui Imam Dental College and Hospital, Bahera, Darbhanga, Bihar, India.
J Contemp Dent Pract. 2012 May 1;13(3):356-63. doi: 10.5005/jp-journals-10024-1151.
The aim of this study was to determine the wettability of different hydrophilic and hydrophobic elastomeric impression materials and the gypsum castability.
The wettability was evaluated by determining the contact angles of different elastomeric impression materials. The contact angle was determined by placing a drop of aqueous solution of calcium sulfate dihydrate on the flat surface of impression material and specimens were measured using a profile projector. Gypsum castability was determined by counting the number of voids formed in the die stone cast made from the impressions of a aluminum die. The voids were counted using an diopter magnifying lens.
Polyether, different viscosities of polyvinyl siloxane, and condensation silicone impression materials exhibited low contact angle values and least number of voids in the die stone cast when compared with polysulfide impression material.
There was significant correlation between the contact angle and voids formed in the die stone casts when fabricating die stone casts from various elastomeric impression material impressions.
Accurate reproduction of prepared tooth or edentulous arch is of clinical importance in the fabrication of a fixed or removable prosthesis. Inaccuracies in the replication processes will ultimately have an adverse effect on the fit and adaptation of final restoration. The interaction is determined in part by hydrophilic and hydrophobic nature of the elastomeric impression material. Inadequate wetting of an impression results in voids in the stone casts.
本研究旨在测定不同亲水和疏水弹性印模材料的润湿性及石膏可铸性。
通过测定不同弹性印模材料的接触角来评估润湿性。将一滴二水硫酸钙水溶液滴在印模材料的平面上，用轮廓投影仪测量接触角。通过计算由铝模印模制成的石膏模型中形成的气孔数量来测定石膏可铸性。使用屈光度放大镜计算气孔数量。
与聚硫印模材料相比，聚醚、不同粘度的聚乙烯基硅氧烷和缩合型硅橡胶印模材料表现出较低的接触角值，且石膏模型中的气孔数量最少。
用各种弹性印模材料制取印模制作石膏模型时，接触角与石膏模型中形成的气孔之间存在显著相关性。
在制作固定或可摘修复体时，准确复制预备牙或无牙弓对临床至关重要。复制过程中的不准确最终会对最终修复体的适合性和贴合度产生不利影响。这种相互作用部分由弹性印模材料的亲水和疏水性质决定。印模湿润不足会导致石膏模型中出现气孔。
