H Xia1, F Xiong2. 1. Department of Maxillofacial Surgery, West China College of Stomatology, Sichuan University, Chengdu 610041, China. 2. Department of Prosthodontics, West China College of Stomatology, Sichuan University, Chengdu 610041, China. E-mail: xofa@163.com.
Abstract
Objective: To study clinical semi-permeability tolerance level in the field of dental restoration. Method: Vita 95 enamel porcelain powder was adopted and 6.0% used as the control transmissivity. Discoid porcelain plates with different transmissivity, namely increasing transmissivity (0.25%, 0.5%, 1.0%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4% and 4.5%) and decreasing transmissivity (-0.25%, -0.5%, -1.0%, -1.5%, -2%, -2.5%, -3% and -3.5%) were made. Forty observers judged these according to six grades: same, similar, slightly different, visibly different, recognizable and significantly different, and under the observation conditions of a neutral grey background and 45°/0° lighting. The judgment results were analysed statistically. Results: When the transmissivity of the control porcelain plates was 6.032%, and the transmissivity of test porcelain plates decreased by 1% or increased by 3%, observers could find slight differences between the test samples and the control samples. When transmissivity of test samples decreased by 2.5% or increased by 4.5%, observers thought that the two porcelain plates belonged to different orders of magnitude. Conclusions: Under the experimental conditions, the upper and lower limits of clinical semi-permeability tolerance were 3% and 1%, respectively.
Objective: To study clinical semi-permeability tolerance level in the field of dental restoration. Method: Vita 95 enamel porcelain powder was adopted and 6.0% used as the control transmissivity. Discoid porcelain plates with different transmissivity, namely increasing transmissivity (0.25%, 0.5%, 1.0%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4% and 4.5%) and decreasing transmissivity (-0.25%, -0.5%, -1.0%, -1.5%, -2%, -2.5%, -3% and -3.5%) were made. Forty observers judged these according to six grades: same, similar, slightly different, visibly different, recognizable and significantly different, and under the observation conditions of a neutral grey background and 45°/0° lighting. The judgment results were analysed statistically. Results: When the transmissivity of the control porcelain plates was 6.032%, and the transmissivity of test porcelain plates decreased by 1% or increased by 3%, observers could find slight differences between the test samples and the control samples. When transmissivity of test samples decreased by 2.5% or increased by 4.5%, observers thought that the two porcelain plates belonged to different orders of magnitude. Conclusions: Under the experimental conditions, the upper and lower limits of clinical semi-permeability tolerance were 3% and 1%, respectively.
Authors: Michael J Heffernan; Steven A Aquilino; Ana M Diaz-Arnold; Debra R Haselton; Clark M Stanford; Marcos A Vargas Journal: J Prosthet Dent Date: 2002-07 Impact factor: 3.426
Authors: Michael J Heffernan; Steven A Aquilino; Ana M Diaz-Arnold; Debra R Haselton; Clark M Stanford; Marcos A Vargas Journal: J Prosthet Dent Date: 2002-07 Impact factor: 3.426