Evidence addressing the stability following a midline diastema closure is believed to be poor, and a paucity of research on this topic has been observed. The study aims to determine diastema closure stability in orthodontically treated patients who underwent a fixed or removable retainer. Forty individuals who received orthodontic treatment for diastema closure were identified using treatment records in orthodontic clinics of a private university hospital in Riyadh city, Saudi Arabia. Panoramic radiographs were taken at debonding stage (T1), and post-treatment follow-up examination (T2) was assessed for relapse. Diastema relapse was believed when the T2-T1 inter-incisor gap was more than zero. The type of retainer therapy post orthodontic treatment was also recorded. The relapse was measured using UNC 15 probe. A Chi-square test, Mann-Whitney U, and Kruskal-Wallis tests were applied to the data. A diastema relapse was deemed clinically significant when it measured 0.50 mm or more. Forty individuals treated for diastema by orthodontic treatment participated in this study. Of the study participants, 50% received a removable retainer while 20% received a fixed retainer, and 25% received both fixed and removable retainers. Diastema stability was observed in 82.5% of cases, while 17.5% showed relapse. Diastema stability did not differ across different retainers (p=0.690) and gender (p= 0.436). Clinically significant relapse was found in six cases. The stability of orthodontically treated diastema closure using fixed and removable retainers was quite substantial.
