RESUMEN
STATEMENT OF PROBLEM: Visual color determination in clinics or dental offices should take place under reproducible environmental conditions. To reduce false tooth color measurements, daylight and illumination lamps (5000-7500 K) have been recommended. Those can be used either as stationary or mobile handheld illumination units. However, depending on the manufacturer, the handheld lights use different illuminance brightness, and whether the choice of unit affects shade selection is unclear. PURPOSE: The purpose of this in vitro study was to determine whether the mobile handheld light-emitting diode (LED) lighting unit shows a significantly better result in visual color determination than the conventional reference lighting unit. MATERIAL AND METHODS: Trained preclinical dental students (N=23) with a mean ±standard deviation age of 24 ±5 years participated in the study. Two color differentiation lamps (Smile lite 1620lx and Dialite Color 4450lx) (SL and DC) were each placed at a 15-cm distance to determine the color of the shade tabs (templates, N=10) with the VITA Linear Guide 3D Master in a double-blinded study. According to the manufacturer's recommendation, polarization filters were used with the Smile lite lamp. RESULTS: Of N=220 shade determinations each, 31.8% (SL) and 33.2% (DC) were correct; the median (ΔE00) and interquartile range were 0.96 (±3.32) for SL and 1.35 (±3.28) for DC. The differences between the groups were not statistically significant (P=.67). CONCLUSIONS: The results show that the use of the mobile LED illumination unit did not improve color determination compared with the reference illumination. The different illumination intensities of 980 lux (SL) with a polarizing filter or 1500 lux (DC) did not have a positive effect.
RESUMEN
PURPOSE: To investigate whether viewing distance influences the results of visual tooth color differentiation. MATERIALS AND METHODS: A total of 65 students underwent both theoretical and practical training by a standardized lecture on the use of an internet learning module (Toothguide Trainer, VITA Zahnfabrik) and a standardized training program (Toothguide Training Box) for visual shade-taking. Each student matched 10 randomly selected shade tabs presented at different viewing distances (arm's length distance [AL, 70 cm] and AL/2 [35cm]) under lateral, non-glare lighting at a 45-degree angle with a color differentiation lamp. The results were recorded as to what extent the presented and selected tabs of the color determination matched. RESULTS: The overall median values of perceived color difference (ΔE) were 1.6 for AL/2 and 3.2 for AL, and these values were significantly different (P < .001). CONCLUSION: Within the limitations of this study, it was shown that the viewing distance had a significant influence on the color deviation in tooth color assessment. Therefore, a smaller viewing distance of 35 cm for shade determination is recommended.
Asunto(s)
Coloración de Prótesis , Diente , Color , Percepción de Color , Diseño de Prótesis Dental , Humanos , IluminaciónRESUMEN
OBJECTIVES: Visual shade selection is the most commonly used method in dentistry and a challenge for every dentist. However, differences to natural tooth color and the differences of each shade guide are well known. The aim of this paper is to investigate the suitability of two different color scales for determining the color of no-match templates. MATERIALS AND METHODS: Volunteers (N = 76) selected a shade color of a no-match template with two shade guides (VITA Classical shade guide (VC) and VITA Linearguide 3D-Master (V3D LG), both Vita Zahnfabrik). The neutral grey background was laterally illuminated with a color differentiation lamp (Dialite, Eickhorst GmbH). For the volunteers' accuracy, the triangle's area was used which are emerge by the color coordinates of a template (LT aT bT ) and the color coordinates of the two decisions (L1 a1 b1 and L2 a2 b2 ). Statistical software was used to evaluate the differences in ΔE00 with α = .01. RESULTS: A deviation in the median of ΔE00 of 7.6 (V3D LG, first choice) to 6.6 (VC, second choice) was detected, while U test showed no significant differences in the median for both color scales. But the triangle's area generated by both shade decisions and tooth color with V3D LG was significant smaller (14.2) then VC (19.2) (P ≤ .001). CONCLUSIONS: When comparing both results no significant difference in the subject's shade selection and the shade guides was detected. The new evaluation strategy using the size of the triangle's areas proves the superiority of the V3D LG due to a better distribution of the tooth color shades within the color space.