Indices that reflect individual oral hygiene levels are widely used to determine microbial plaque of the tooth surface. When teaching patients how to take care about the oral cavity, dentists use visual demonstration of the dental plaque localization. The quantitative light-induced fluorescence (QLF) technique represents a modern method to diagnose individual oral hygiene, in which even minimal microbial plaque buildup shows up as red fluorescence. The study aimed to assess the oral hygiene status using the quantitative light-induced fluorescence technique. Dental deposits were detected using QLF; the Quigley Hein, Green-Vermillion, DMF indices were detected clinically. The findings show that Simple Hygiene Scores do not exceed 2, when the caries intensity is very low or low (p < 0.05). In these groups, the Green-Vermillion and Quigley Hein index values reach 0.5 ± 0.23 and 0.2 ± 0.14, respectively. When the caries intensity is medium, Simple Hygiene Scores vary between 1–5 points. Very high caries intensity is characterized by the Simple Hygiene Score between 3 and 5 points (maximum Green-Vermillion and Quigley Hein index values reach 2.3 ± 0.43 and 2.1 ± 0.35) (p < 0.05). Thus, the quantitative light-induced fluorescence technique can be used in clinical trials for objective oral hygiene assessment, visual demonstration of dental plaque buildup to patients, and assessment of the dynamic changes in these indicators.