Effect of Ceramic Thickness and Technician Variability on the Shade Duplication of Dental Ceramo-Metallic Restorations

Rasha M Abdelraouf; Taheya A Moussa; Tamer M Hamdy; Reem A Abuhaimed; Alanoud M Alotaibi; Carlos A Jurado; Abdulaziz Alhotan; Bushra Alhelal; Nour A Habib

doi:10.3390/jfb15010012

Effect of Ceramic Thickness and Technician Variability on the Shade Duplication of Dental Ceramo-Metallic Restorations

J Funct Biomater. 2023 Dec 28;15(1):12. doi: 10.3390/jfb15010012.

Authors

Rasha M Abdelraouf¹, Taheya A Moussa¹, Tamer M Hamdy², Reem A Abuhaimed³, Alanoud M Alotaibi³, Carlos A Jurado⁴, Abdulaziz Alhotan⁵, Bushra Alhelal³, Nour A Habib¹

Affiliations

¹ Biomaterials Department, Faculty of Dentistry, Cairo University, Cairo 11553, Egypt.
² Restorative and Dental Materials Department, Oral and Dental Research Institute, National Research Centre (NRC), El Bohouth St., Dokki, Giza 12622, Egypt.
³ Dental Interns, College of Dentistry, King Saud University, P.O. Box 60169, Riyadh 11545, Saudi Arabia.
⁴ Department of Prosthodontics, University of Iowa College of Dentistry and Dental Clinics, Iowa City, IA 52242, USA.
⁵ Department of Dental Health, College of Applied Medical Sciences, King Saud University, P.O. Box 10219, Riyadh 12372, Saudi Arabia.

Abstract

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 (n = 30/gp) according to the different technicians who built up the veneering ceramic of the specimens. Each group was further subdivided into three subgroups (n = 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.

Keywords: ceramic thickness; ceramics; ceramo-metallic restorations; metal ceramic; shade duplication; technician variability.

Grants and funding

This research was funded by Researchers Supporting Project number (RSPD2023R790), King Saud University, Saudi Arabia, Riyadh.