Orthodontic therapy is associated with a more significant accumulation of dentobacterial plaque and impaired oral hygiene, which increase the risk of developing dental caries and periodontal disease. Therefore, it is crucial to educate orthodontic patients about proper oral hygiene maintenance and oral health before and during treatment. The aim of this pilot study was to implement evidence-based best practices related to oral hygiene in adult orthodontic patients and improve compliance. In addition to evaluating oral hygiene practices, another goal of the project was to assess the knowledge of orthodontic patients regarding oral health. Questionnaires with seven pre- (before) and post-test criteria (90 day after implementation) were developed based on the best evidence available. This project was conducted in a private dental clinic in Split, Croatia, and included 45 patients. The baseline audit showed a gap between clinical practice and the best evidence. Three criteria achieved a high compliance baseline, while after implementation, there were substantial improvements in compliance for all. The everyday use of mouthwash improved from 17.8% at baseline to 66.7% at follow-up, as did the use of interdental aids, which increased from 55.6% to 91.1%. Statistically significant differences were found in the total score for oral health knowledge between the baseline (6.67 ± 1.74) and the follow-up audit (7.78 ± 0.56, p ≤ 0.001). The strategies developed in this project were effective in providing essential information to adult orthodontic patients and improving compliance with evidence. Guidelines on this topic should be designed to assist orthodontists and patients in maintaining oral health and oral hygiene.