Whiteness difference thresholds in dentistry. Issue 2 (February 2019) - Pérez, María M.
Abstract: Objective: To determine the visual whiteness thresholds for esthetic dentistry using the whiteness index for dentistry based on CIELAB color space (WID ). Methods: A total of 60 observers (Dentists and Laypersons; n = 30) from three research sites participated in the study. A psychophysical experiment based on visual assessments of simulated images of teeth on a calibrated display was performed. Images of simulated upper central incisors (SUCI) were consecutively displayed in pairs (60) and the whiteness of each SUCI pair was compared. WID was used to calculate the visual thresholds (WPT- perceptibility threshold; and WAT- acceptability threshold) with 95% confidence intervals (CI) and a Takagi-Sugeno-Kang (TSK) Fuzzy Approximation model was used as fitting procedure. Data was statistical analyzed using paired t -test ( α = 0.05). Results: WPT and WAT were 0.72 (CI: 0.0–2.69; r 2 = 0.52) and 2.62 (CI: 0.2-7+; r 2 = 0.57) WID units, respectively. Significant differences (p < 0.05) were found between WPT and WAT, and between dentist (WPT = 0.46WID units; WAT = 2.20 WID units) and layperson (WPT = 0.94 WID units; WAT = 2.95 WID units). Significance: The visual whiteness difference thresholds determined with WID index can serve as reference values for research and manufacturing of dental materials, and for clinical practice situations such as assessing the effectiveness of bleaching treatments.