Red fluorescence imaging for dental plaque detection and quantification: pilot study

Abstract

The red fluorescence of dental plaque originating from porphyrins in oral bacteria may allow visualization, detection, and scoring of plaque without disclosing agents. Two studies were conducted. The first included 24 healthy participants who abstained from oral hygiene for 24 h. Dental plaque was collected from tooth surfaces, and a 10% solution was prepared. These were scanned by a molecular spectrometer to identify the optimum excitation and emission wavelengths of plaque for developing a red fluorescence imaging system. Fourteen healthy subjects completed the second study. After a washout period (1 week), participants had a prophylaxis at baseline and abstained from oral hygiene during the study. They were monitored using the fluorescence imaging system at baseline, 24 h, and 48 h. A dentist clinically assessed plaque after disclosing and on red fluorescence images. Three descriptors were extracted from images and a RUSBoost classifier derived computer fluorescence scores through cross-validation. Red fluorescence plaque levels increased during the 48-h accumulation. Plaque progression was identified by dentist assessment and computer analysis, presenting significant differences between visits at tooth and subject levels (p<0.05). Moderate correlations showed between clinical plaque and red fluorescence plaque (r=0.62 dentist, r=0.55 computer). The best agreement was observed when disclosing plaque threshold at level 2, for both dentist evaluation (sensitivity 71.1%, specificity 67.7%, accuracy 70.2%) and computer classification (sensitivity 68.4%, specificity 62.9%, accuracy 67.1%). Given the correlation with clinical diagnosis, red fluorescence imaging shows its potential for providing an objective and promising method for proper oral hygiene assessment.

Autofluorescence Detection Method for Dental Plaque Bacteria Detection and Classification: Example of Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, and Streptococcus mutans

“…The red fluorescence has been found in a biofilm that might be originated from porphyrins produced during bacterial metabolites [ 7 ]. The red fluorescence has been used to detect dental caries, oral malodor, and dental plaque [ 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ]. Coulthwaite et al observed the fluorescence of plaque on dentures using 366 nm excitation light sources [ 7 ].…”

“…Joseph et al detected dental plaque in situ based on laser-induced autofluorescence spectroscopy equipped with a 404 nm excitation light source [ 9 ]. Liu et al detected in-vitro dental plaque based on red fluorescence with a 405 nm excitation light source [ 10 ]. The wavelength of the excitation light sources in these studies seems inconsistent.…”

Handheld optical coherence tomography for clinical assessment of dental plaque and gingiva

“…5 Surface dental plaque can also be revealed with fluorescence imaging as well. 6,7 However, these methods are often confined to tissue surfaces, and thus may not provide detailed information when monitoring the therapeutic effects and the disease progression. One method to examine severe gingival conditions is to measure the pocket depth using a periodontal probe inserted into the gum pocket.…”

Deep learning-based dental plaque detection on primary teeth: a comparison with clinical assessments

“…The development of digital cameras coupled with image analysis software yielded the first attempts to develop an imaging system capable of capturing pictures of disclosed plaque and performing automated measurements of plaque coverage [18,19]. The proposed approach provides automatic measurements of plaque coverage on the facial surfaces of teeth using an AI model based on deep learning.…”