Histogram-Corrected Intraoral Photographs for Early Gingivitis Screening in Orthodontic Patients

Gingivitis has a significant impact on periodontal health, both during and after orthodontic treatment. Early detection and management are essential for minimizing tissue damage. This study investigated an early gingivitis detection method using intraoral photographs (IOPs) taken before, at the midpoint (MO), and three-quarters of the way through orthodontic treatment (TO), as well as immediately after debonding (IDO).

To accurately measure gingival redness, the red/green (R/G) ratio and grayscale visible-light value were calculated from IOPs using two methods: histogram-based and grey value-based intensity correction (HIC and GIC). The correlations between the gingival index (GI) and these metrics were then analysed.

The GI increased at TO and IDO, with significant variation across gingival locations (p < 0.05). HIC analysis revealed increased R/G ratios in the papillary gingivae at TO and IDO (p < 0.01). GIC analysis showed higher visible-light values at MO, which decreased at TO and IDO (p < 0.01). The HIC R/G ratio correlated positively with the GI at IDO in both the maxillary (r = 0.581, p < 0.001) and mandibular (r = 0.556, p < 0.001) gingivae. Conversely, GIC values were negatively correlated with the GI at IDO for the maxillary (r = -0.505, p < 0.05) and mandibular (r = -0.407, p < 0.05) gingivae.

This study demonstrates the potential of using HIC IOPs as an early screening tool for gingivitis. By applying image-correction techniques, this novel method enhances diagnostic precision and paves the way for personalized oral disease management through early intervention and tailored patient care.