Purpose: In periodontally healthy individuals, mean crevicular depth ranges from 1 to 3 mm. This depth threshold has been used as an indicator to differentiate a physiological dentoalveolar sulcus from a periodontal pocket needing further treatment. Because many studies have shown the important contribution of oral hygiene status to periodontal health, the purpose of this study was to explore the clinical effect of reinforced oral hygiene on the periodontal status of periodontitis-free dental students. Materials and Methods: In our longitudinal observational clinical study, we assessed the periodontal status of healthy individuals attending the dental school by measuring the periodontal pocket depth, bleeding on probing, and plaque index. The follow-up reassessment was carried out four years later at the end of the dental curriculum. Results: The study showed that oral hygiene improvement led to a slight but significant reduction in the mean sulcus depth (-0.049 mm; p < 0.0001). Conclusions: Reinforcement of oral hygiene contributes to the reduction of probing depth even in periodontally healthy patients.