Abdelraouf Rasha M, Moussa Taheya A, Hamdy Tamer M, Abuhaimed Reem A, Alotaibi Alanoud M, Jurado Carlos A, Alhotan Abdulaziz, Alhelal Bushra, Habib Nour A
Biomaterials Department, Faculty of Dentistry, Cairo University, Cairo 11553, Egypt.
Restorative and Dental Materials Department, Oral and Dental Research Institute, National Research Centre (NRC), El Bohouth St., Dokki, Giza 12622, Egypt.
J Funct Biomater. 2023 Dec 28;15(1):12. doi: 10.3390/jfb15010012.
Ceramic thickness and technicians' manipulative variables are critical factors affecting the resultant shade of dental ceramo-metallic restorations. This study investigated the effect of the following variables on shade duplication of ceramo-metallic specimens: (a) ceramic thickness; (b) differences between several technicians (inter-technician variability); and (c) the ability of each technician to repeat the resultant shade (intra-technician variability). Ninety ceramo-metallic specimens were prepared and divided into three main groups ( = 30/gp) according to the different technicians who built up the veneering ceramic of the specimens. Each group was further subdivided into three subgroups ( = 10/subgroup) according to the thickness of the ceramic (1, 1.5, and 2 mm built over a 0.5 mm-thick metal substructure). Three different technicians were asked to follow the same protocol as regards the same ceramic batch (Shade 3M2, Vita VM13, Zahnfabrik, Germany), firing temperature, and number of firing cycles. Meanwhile, each technician followed his own protocol with regard to other ceramic manipulative variables. The duplicated shades of the specimens were investigated using the Vita Easyshade spectrophotometer by using the verify shade mode. Color difference (∆E) values were calculated between the target shade (3M2) and the duplicated shades of the specimens automatically by the Vita Easyshade spectrophotometer (Vita, Zahnfabrik, Germany). The effect of ceramic thickness and inter- and intra-technician variability on the duplication of the target shade was investigated. The results showed that the effect of ceramic thickness on the duplicated shades depended on inter-technician variability. High inter-technician variability (∆E = 2-6.4) was noticed in contrast to low intra-technician variability (∆E = 0.2-1.5). It could be concluded that proper shade-duplication of ceramo-metallic restoration was a cumulative technique intimately related to manipulative variables and ceramic thickness.
陶瓷厚度和技师的操作变量是影响牙科烤瓷熔附金属修复体最终颜色的关键因素。本研究调查了以下变量对烤瓷熔附金属试件颜色复制的影响：（a）陶瓷厚度；（b）几位技师之间的差异（技师间变异性）；以及（c）每位技师重复最终颜色的能力（技师内变异性）。制备了90个烤瓷熔附金属试件，并根据制作试件 veneering 陶瓷的不同技师分为三个主要组（每组 = 30个）。每组又根据陶瓷厚度（在0.5毫米厚的金属基底上制作的1、1.5和2毫米）进一步细分为三个亚组（每个亚组 = 10个）。要求三名不同的技师在相同的陶瓷批次（3M2色号、Vita VM13、德国 Zahnfabrik）、烧制温度和烧制周期数方面遵循相同的方案。同时，每位技师在其他陶瓷操作变量方面遵循自己的方案。使用Vita Easyshade分光光度计通过验证颜色模式研究试件的复制颜色。Vita Easyshade分光光度计（德国 Vita、Zahnfabrik）自动计算目标颜色（3M2）与试件复制颜色之间的色差（∆E）值。研究了陶瓷厚度以及技师间和技师内变异性对目标颜色复制的影响。结果表明，陶瓷厚度对复制颜色的影响取决于技师间变异性。与低技师内变异性（∆E = 0.2 - 1.5）相比，注意到了高技师间变异性（∆E = 2 - 6.4）。可以得出结论，烤瓷熔附金属修复体的正确颜色复制是一种与操作变量和陶瓷厚度密切相关的累积技术。
