Objective: This study aimed to evaluate proximal caries formation and Decay, Missing, Filled Teeth (DMFT) scores during clear aligner (CA) therapy compared with fixed orthodontic treatment. Methods: A total of 50 patients with a mean age of 19.9 years were divided into two equal groups (n=25) according to treatment method. Both CA and fixed appliance (FA) patients had low-to-medium levels of crowding. Caries formation and DMFT scores were assessed via radiographic and clinical examination before treatment (T0) and at the end of a six-month observation period (T1). The numbers of caries lesions and fillings was analyzed using a Two-Way Analysis of Variance with a significance level of 0.05. Results: Significant statistical differences were found for both groups (p