CIELab Colour Coordinate Changes Associated with the Resolution of Gingival Inflammation: Influence of Biotype and Severity

Background/Objectives: The colour changes related to inflammation have yet to be quantified despite the fact that the intensification of gingival colour is one of the cardinal signs of gingival inflammation. We aimed to (1) assess the effect of periodontal treatment on gingival colour according to biotype and initial degree of inflammatory severity and (2) identify the relationship between the plaque index and gingival colour and compare the colour of moderately or severely inflamed gums to the colour of gums with mild inflammation. Methods: Forty-three participants with visual signs of inflammation were included in the study. CIELAB colour coordinates were measured using a spectrophotometer at the distal papilla, free gingival margin, middle zone of the attached gingiva, and mucogingival line proximate to the maxillary central incisor pre-treatment and four weeks post treatment with periodontal debridement. Each participant’s gingival biotype, plaque and gingival indices, age, and gender were also recorded. Results: The biotype and plaque index were both found to influence the colour of inflamed gums, albeit only the a* coordinate in two of the zones examined (the distal papilla and free gingival margin). Statistically significant differences were also found between the a* coordinates of participants with and without plaque at the distal papilla and the free gingival margin. The severity of inflammation also influenced the L* coordinates of gingival colour (p < 0.001) in all participants in all four zones examined. Periodontal treatment only affected the L* coordinate of gingival colour at the distal papilla and the free gingival margin. Conclusions: When gingival inflammation occurs, participants with thin biotype and plaque have redder gums, and moderately or severely inflamed gingiva have a visually perceptible darker colour. Periodontal treatment significantly increases the lightness of the distal papilla and the free gingival margin. Further, periodontal treatment creates a perceptible colour change in all zones under study, which is not dependent on either the patient’s biotype or initial severity of inflammation. Clinical Significance. Digital spectrophotometric analysis provides a valuable technological enhancement to quantify gingival colour and record changes in gingival colour during the course of periodontal treatment. Regardless of the initial severity of gingival inflammation, a perceptible increase in the L* coordinate (gums become visibly lighter) can be expected after periodontal treatment. Regardless of the initial severity of inflammation, a perceptible increase in the L* coordinate can be expected (gums become visibly lighter) after treatment.