Oral and dental diseases are common in horses, as evidenced by the results of incidence studies of dental diseases carried out on abattoir specimens or sports horses. Thus, periodic dental examinations in horses are essential to ensure the maintenance of dental health and proper use of ingested food. A retrospective study of the dental records of 416 Quarter Horses (256 males, 160 females), distributed in the western region of the Rio Grande do Norte, Brazil, was conducted. Horses were examined between July 2012 and August 2022. The variables collected were age, sex, type of diet, dental alterations identified, and history of colic in the last 365 days. The animals were divided into three groups according to age: group I (2 to 6 years old), group II (7to12 years old), and group III (13to 24 years old). Pairwise comparisons were performed using Tukey's correction. The most frequent dental alterations were excessive tip of the tooth enamel, limited/asymmetric lateral excussion, oral ulceration, eruption of the first premolar tooth, and rostral hook. Statistical differences (p<0.05) were observed between the age groups in the following alterations: excessive tip of the tooth enamel, limited/asymmetric lateral excussion, eruption of the first premolar tooth, rostral hook, palatitis, step, caudal hook, retention of deciduous cheek teeth, wave, tartarus, underbite, periodontal disease, and incisors of the dorsal curve. Dental disorders in horses are of major clinical importance.