Colour thresholds of the gingival chromatic space

Cristina Gómez-Polo; Ana María Martín Casado; Miguel Gómez-Polo; Javier Montero

doi:10.1016/j.jdent.2020.103502

Colour thresholds of the gingival chromatic space

J Dent. 2020 Dec:103:103502. doi: 10.1016/j.jdent.2020.103502. Epub 2020 Oct 15.

Authors

Cristina Gómez-Polo¹, Ana María Martín Casado², Miguel Gómez-Polo³, Javier Montero⁴

Affiliations

¹ Department of Dentistry, School of Medicine, University of Salamanca, Campus Miguel de Unamuno s/n, 37007, Spain. Electronic address: crisgodent@usal.es.
² Department of Statistics, School of Medicine, University of Salamanca, Spain. Electronic address: ammc@usal.es.
³ Department of Prosthodontics, School of Dentistry, University of Complutense, Madrid, Spain. Electronic address: mgpolo@odon.ucm.es.
⁴ Department of Surgery, School of Medicine, University of Salamanca, Spain. Electronic address: javimont@usal.es.

PMID: 33069771
DOI: 10.1016/j.jdent.2020.103502

Abstract

Objective: To establish the thresholds of chromatic perception and clinical acceptability of gingival colour according to professional category and in accordance with the perceptibility/acceptability threshold of 50:50 (colour differences that can be perceived/accepted by 50 % of the observers).

Methods: A total of 21 different coloured samples made of pink gingiva Heraceram porcelain were used. Dentists (n = 54), dental assistants (n = 56), dental students (n = 126) and participants unrelated to dentistry (n = 116) were asked to identify pairs of samples that appeared identical. In addition, they were asked to indicate the pairs of samples whose colour they considered to be acceptable for use in a dental rehabilitation. A least squares regression was adjusted using an S-shaped curve of the equation y = exp (B0 + B1/x). The adjusted model was used to predict a colour difference value for an acceptability percentage of 50 %.

Results: The threshold value for the perception of colour changes in human gingiva varies from ΔEab* 2.3 ± 0.38 units and CIEDE2000 (ΔE00) 1.5 ± 0.28units (dental students) to ΔEab* 2.7 ± 0.43 units and ΔE00 1.8 ± 0.30 units (participants unrelated to dentistry). The threshold of gingival acceptability varies from ΔEab* 2.9 ± 0.43 units and ΔE00 2.0 ± 0.31 units (dental assistants) to ΔEab* 3.6 ± 0.54 units and ΔE00 2.5 ± 0.41 units (dental students).

Conclusion: From the total number of samples, the average threshold of perception for the gingival chromatic space is 3.1 units for ΔEab* and 2.1 units for ΔE00. Moreover, the mean gingival acceptance threshold is 4.1 units for ΔEab* and 2.9 units for ΔE00. These thresholds are similar for all professional categories studied.

Clinical significance: The determination of the perception and acceptability thresholds in the gingival chromatic space are of special relevance for designing the physical shade tabs used in gingival colour guides. The results from this work will aid in selecting optimal gingival colour for patients.

Keywords: Acceptation threshold; Gingival colour; Gingival porcelain; Perception threshold.

MeSH terms

Color
Color Perception
Dental Porcelain*
Gingiva*
Humans

Substances

Dental Porcelain