Clinical and Digital Imaging Assessment of Dental Plaque With Two Different Toothpastes in Children: A Randomized Crossover Clinical Trial

OBJECTIVE: To evaluate the performance of an intraoral digital image-based system for detecting and quantifying dental plaque using digital image analysis, with the Turesky Modified Quigley-Hein Plaque Index (TMQHPI) serving as the clinical reference standard, and secondarily to assess the system's ability to distinguish plaque differences between two toothpaste formulations. METHOD: In this short-term, randomized, examiner-blinded, crossover clinical trial, children used two different toothpaste formulations twice daily for two minutes over two-week periods separated by standardized run-in and wash-out phases. Plaque assessments were performed under habitual conditions (T0), at baseline (T1), and after toothbrushing (T2) using the TMQHPI and standardized intraoral digital photographs. Digital plaque analysis was conducted using ImageJ software through threshold-based image segmentation to calculate the plaque-covered area and its proportion relative to the total tooth surface area. RESULTS: Forty children were enrolled and randomised (mean age: 10.25 ± 1.06 years; 52.5% girls, 47.5% boys). Plaque levels assessed using clinical indices and digital image analysis were high at baseline and decreased significantly after toothbrushing in both groups (p < 0.01). Linear mixed-effects model analysis demonstrated significantly lower post-brushing TMQHPI scores, Digital Plaque Area, and Digital Area Fraction values in the magnesium-containing toothpaste group compared with the fluoride toothpaste group (all p < 0.001). Significant positive correlations were observed between clinical plaque scores and digital plaque measurements (ρ = 0.76-0.87; p < 0.001). CONCLUSION: Intraoral image-based digital plaque analysis was consistent with clinical TMQHPI scores and effectively reflected short-term changes in plaque accumulation in children. Although greater reductions were observed in selected plaque-related parameters with the magnesium-containing formulation, these findings should be interpreted cautiously given the short study duration. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT05868590.