Establishment and evaluation of a 3D quantitative analysis method for dental plaque based on an intraoral scanner technique.

Aim: Quantitative dental plaque evaluation is necessary for clinical and scientific work. The present study aimed to examine the reliability of a 3D image analysis method by digitally analyzing the color 3D images obtained from an intraoral scanner (IOS) and then detecting and quantifying the plaque information and comparing it with the clinical examination results.

Materials and methods: A total of 140 teeth from five subjects with a standard dentition were enrolled. Plaque examination was performed at two different time points: after 24 h without oral hygiene (T1), and after habitual brushing (T2). At each time point, the Quigley-Hein Plaque Index (PI) of each tooth surface was recorded separately, followed by color 3D images obtained using an IOS, and image analysis and calculation using Geomagic Wrap 2021 software.

Results: The percentage of plaque staining area calculated from the 3D image analysis correlated well with the PI recorded during the clinical examination: the Spearman correlation coefficients were 0.9136 and 0.9061 (P < 0.001) for all tooth surfaces at T1 and T2, respectively. The measurements of the three investigators were in good agreement, with intraclass correlation coefficients of 0.989 and 0.992 (P < 0.001) for the vestibular and lingual surfaces at T1, respectively, and 0.964 and 0.983 (P < 0.001) for the vestibular and lingual surfaces at T2, respectively.

Conclusion: In the present study, a digital 3D evaluation system of dental plaque suitable for research and clinical practice was initially developed and its reliability demonstrated.