Influence of tongue position on the determination of tooth shade

Comparison of different illumination intensities of mobile units for tooth color differentiation: An in vitro study

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.

Visual Versus Digital Color Determination of 3D-Printed Teeth as an Exercise in Dental Students' Education

Visual color determination is part of the daily routine in dental practice. However, it is not a part of dental education so far. The aim of this study was to evaluate whether visual or digital tooth color determination of 3D-printed teeth is a reliable tool for inexperienced dentistry students. Preclinical dental students evaluated eleven 3D-printed, tooth-shaped samples (VarseoSmile Crown plus, BEGO, Bremen, Germany) of different color shades. Visual shade determination using a reference scale (3D-Master Toothguide (3DM_TG), VITA Zahnfabrik, Bad Säckingen, Germany), followed by a digital color determination using a spectrophotometer (VITA Easyshade V, (ES_V), VITA Zahnfabrik), was performed. Color deviation was calculated in the Lab* color space (ΔE00) and converted into CIELAB 2000. The results were evaluated using the Mann-Whitney U test and the Wilcoxon Rank Sum test (α = 0.05). Significant differences between visual and digital color determination were proven (p < 0.001). Visual color determination (3DM_TG) showed a mean deviation (ΔE00 ± 95%CI) of 6.49 ± 0.47. Digital color determination (ES_V) showed significantly lower mean deviations of ΔE00 of 1.44 ± 0.58. Digital tooth color measurement using a spectrophotometer was a more reliable tool for the color determination of 3D-printed teeth for inexperienced dentistry students.

The Influence of Dental Occlusion on Spectrophotometric Tooth Color Determinations

Background:

Shade matching is a significant treatment step and a challenge for the clinical team with potentially high costs for color correction. Currently, in the United States, the majority of private dental practitioners use visual color matching, but a recent study has reported a high rate of mistakes of subjective color determination among graduate dentists.

Objective:

The aim of this retrospective study is to analyze whether a change in the oral background due to dental occlusion can influence tooth color determination.

Methods:

Volunteer dental students underwent spectrophotometric color assessment using the SpectroShade device. Two measurements were carried out (with the individuals’ occlusion closed and with the occlusion open) on 43 upper central and 58 lateral incisors. Association between colorimetric variables L*, a*, b* and ΔE00 and tooth width, length and tobacco usage were examined.

Results:

Slight changes in the CIELAB values between closed and open occlusions were found for both the gingival and the central sections as for the overall tooth area, with mean ΔL*=-1.24, Δa*=-1.77, Δb*=-1.42 and ΔE00=1,84. A larger difference was detected in the incisal area, with mean ΔL*=-2.99, Δa*=-1.76, Δb*=-2.83 and ΔE00=3.65.

Conclusion:

In conclusion, our study showed that dental occlusion does not play a significant role in tooth color matching determinations, even though attention to avoid overbite due to a maximum intercuspation should be made.

Effectiveness of a protocol for teaching dental tooth color in students with color vision impairment

OBJECTIVE

In patients with color vision alterations (CVA), the correct determination of color is altered, but not the detection of changes in luminosity or value. There is no accepted training protocol for dental value selection in dental students with CVA. The objective of this pilot study was to determine the effectiveness of a dental color training protocol based on the dental value selection.

MATERIALS AND METHODS

An intervention study was carried out on dental students in a University setting, applying a specific dental color training protocol on two groups of students. Group 1:4 students with CVA, Group 2:4 healthy students. A third group of four students without intervention was used as a control group. An initial diagnostic test was applied, which was reapplied at the end of the training.

RESULTS

The number of errors in the selection of the dental color decreased after training in all three groups, P > .05. For the value parameter, there was a statistically significant decrease in the number of errors after training (P = .014).

CONCLUSIONS

The applied training protocol could be of help in students with CVA, but multicenter studies are needed.

CLINICAL SIGNIFICANCE

Level 3 evidence level.