Haralur Satheesh B, Hamdi Osama A, Al-Shahrani Abdulaziz A, Alhasaniah Sultan
Department of Prosthodontics, College of Dentistry, King Khalid University, Abha, Saudi Arabia.
J Int Soc Prev Community Dent. 2017 Jan-Feb;7(1):52-57. doi: 10.4103/jispcd.JISPCD_483_16. Epub 2017 Feb 21.
To evaluate the effect of varying cellulose casting ring liner length and its prewetting on the marginal adaptation and dimensional accuracy of full veneer metal castings.
The master die was milled in stainless steel to fabricate the wax pattern. Sixty wax patterns were fabricated with a uniform thickness of 1.5 mm at an occlusal surface and 1 mm axial surface, cervical width at 13.5 mm, and 10 mm cuspal height. The samples were divided into six groups ( = 10). Groups I and II samples had the full-length cellulose prewet and dry ring liner, respectively. The groups III and IV had 2 mm short prewet and dry cellulose ring liner, respectively, whereas groups V and VI were invested in 6 mm short ring liner. The wax patterns were immediately invested in phosphate bonded investment, and casting procedure was completed with nickel-chrome alloy. The castings were cleaned and mean score of measurements at four reference points for marginal adaption, casting height, and cervical width was calculated. The marginal adaption was calculated with Imaje J software, whereas the casting height and cervical width was determined using a digital scale. The data was subjected to one-way analysis of varaince and Tukey statistical analysis with Statistical Package for the Social Sciences version 20 software.
The group II had the best marginal adaption with a gap of 63.786 μm followed by group I (65.185 μm), group IV (87.740 μm), and group III (101.455 μm). A large marginal gap was observed in group V at 188.871 μm. Cuspal height was more accurate with group V (10.428 mm), group VI (10.421 mm), and group II (10.488 mm). The cervical width was approximately similar in group I, group III, and group V. Statistically significant difference was observed in Tukey analysis between group V and group VI with all the other groups with regards to marginal adaptation.
The dry cellulose ring liners provided better marginal adaptation in comparison to prewet cellulose ring liners. Accurate cuspal height was obtained with shorter ring liner in comparison to full-length cellulose ring liners.
评估不同长度的纤维素铸圈衬里及其预湿处理对全冠金属铸件边缘适合性和尺寸精度的影响。
用不锈钢铣削母模以制作蜡型。制作60个蜡型，其咬合面厚度均匀为1.5mm，轴面厚度为1mm，颈部宽度为13.5mm，牙尖高度为10mm。将样本分为六组（每组n = 10）。第一组和第二组样本分别使用全长预湿和干燥的纤维素铸圈衬里。第三组和第四组分别使用2mm短的预湿和干燥纤维素铸圈衬里，而第五组和第六组则使用6mm短铸圈衬里包埋。蜡型立即用磷酸盐粘结包埋材料包埋，并用镍铬合金完成铸造过程。铸件经清洁后，计算四个参考点处边缘适合性、铸件高度和颈部宽度测量的平均得分。边缘适合性用Imaje J软件计算，铸件高度和颈部宽度用数字天平测定。数据采用社会科学统计软件包20版进行单因素方差分析和Tukey统计分析。
第二组边缘适合性最佳，间隙为63.786μm，其次是第一组（65.185μm）、第四组（87.740μm）和第三组（101.455μm）。第五组的边缘间隙较大，为188.871μm。第五组（10.428mm）、第六组（10.421mm）和第二组（10.488mm）的牙尖高度更精确。第一组、第三组和第五组的颈部宽度大致相似。在Tukey分析中，第五组与第六组以及与所有其他组在边缘适合性方面存在统计学显著差异。
与预湿纤维素铸圈衬里相比，干燥纤维素铸圈衬里提供了更好的边缘适合性。与全长纤维素铸圈衬里相比，较短的铸圈衬里能获得更精确的牙尖高度。
