<![CDATA[Background: Orthodontic relapse remains a common complication after active treatment, with reported rates of 70-90% during the retention period, and retainer-related failure is a major contributing factor. Because the long-term stability of orthodontic correction depends heavily on the patient's own adherence to retainer wear, patient knowledge of the purpose, protocol, and consequences of neglecting retention is considered an important determinant of treatment success, yet this relationship has received limited attention in the orthodontic literature. Objective: This study aimed to evaluate the association between patient knowledge and the success of retainer treatment in preventing orthodontic relapse. Materials and Methods: This retrospective cross-sectional study included 33 orthodontic patients over 18 years of age who were undergoing the retention phase after active treatment at Nala Husada Dental Hospital, Surabaya, Indonesia, between November 2024 and February 2025. Data were collected using a structured online questionnaire distributed through Google Forms, consisting of 12 items covering patient knowledge, therapeutic communication, and compliance regarding retainer use. Responses were coded numerically, and the association between patient knowledge and the success rate of retainer treatment was analyzed using the Spearman rank correlation test, with statistical significance set at p<0.05. Results: Female participants constituted the majority of respondents (81.8%). Most participants demonstrated a very good level of knowledge regarding retainer treatment (72.7%), while 18.2% had poor knowledge and 9.1% had very poor knowledge. A significant positive correlation was found between patient knowledge and the success rate of retainer treatment (r=0.671; p=0.024), indicating a strong relationship: patients with greater knowledge of retainer care achieved more successful treatment outcomes. Conclusion: Patient knowledge was significantly associated with the success of retainer treatment in preventing orthodontic relapse. These findings underscore the importance of structured patient education during the retention phase to improve long-term orthodontic stability.]]>
