Gajbhiye Vijeta, Banerjee Rajlakshmi, Jaiswal Priti, Chandak Anuj, Radke Usha
Department of Prosthodontics, VSPM Dental College and Research Centre, Nagpur, Maharashtra, India.
J Indian Prosthodont Soc. 2019 Apr-Jun;19(2):173-179. doi: 10.4103/jips.jips_285_18.
Displacement of gingiva is essential for obtaining accurate impressions for the fabrication of fixed prostheses, particularly when the finish line is at or within the gingival sulcus. Various newer impression materials have been introduced to achieve gingival displacement while recording the impressions. A comparative evaluation of these new gingival displacement materials was deemed necessary for efficacy in tissue management and dimensional accuracy.
Ten individuals were selected according to the inclusion and exclusion criteria for gingival displacement using retraction cord impregnated with aluminum chloride and two polyvinyl siloxane impression materials (Aquasil and NoCord VPS impression system) according to Latin block design. Intraoral scanner and Vernier caliper were used to study and compare the dimensional accuracy of each die obtained following which the dies were sectioned and evaluated under optical microscope with image analyzer to measure the amount of gingival retraction.
Statistical analysis showed that the amount of gingival retraction obtained by using retraction cord impregnated with aluminum chloride as gingival retraction agent was maximum as compared to NoCord followed by Aquasil. All three gingival displacement techniques could produce gingival displacement >0.2 mm which is the optimum amount of retraction required for impression making. All the three materials are found to be dimensionally accurate.
牙龈移位对于获取用于制作固定修复体的精确印模至关重要,尤其是当边缘线位于龈沟内或龈沟处时。为在记录印模时实现牙龈移位,已引入了各种新型印模材料。对这些新型牙龈移位材料在组织管理效果和尺寸精度方面进行比较评估被认为是必要的。
根据使用浸渍有氯化铝的收缩线和两种聚乙烯基硅氧烷印模材料(Aquasil和NoCord VPS印模系统)进行牙龈移位的纳入和排除标准,按照拉丁方设计选择了10名个体。使用口腔内扫描仪和游标卡尺研究并比较每个铸模的尺寸精度,之后将铸模切片并在光学显微镜下用图像分析仪评估以测量牙龈退缩量。
统计分析表明,与NoCord和Aquasil相比,使用浸渍有氯化铝的收缩线作为牙龈退缩剂获得的牙龈退缩量最大。所有三种牙龈移位技术均可产生大于0.2mm的牙龈移位,这是印模制作所需的最佳退缩量。发现所有三种材料在尺寸上都是精确的。