This study aims to investigate the correlation between open-mouth breathing and temporomandibular joint morphology by examining CT data in patients. From January to December 2022, 31 patients with open-mouth breathing and 20 with normal breathing were chosen from those attending the Stomatological Hospital of Chongqing Medical University. We compared condylar measurements among normal breathers (NB), pre-operative open-mouth breathers (Pre-OB), and post-operative open-mouth breathers (Post-OB) to identify statistically significant differences. Upon comparing the measurement parameters of the NB with the Pre-OB, we found significant statistical differences in the bilateral condylar height, depth of the articular fossa, anterior joint space, and the anterior inclined plane length of the condyle (p < 0.05).Further examination of the Pre-OB, when considering duration of open-mouth breathing, revealed pronounced differences in the condylar mediolateral diameter, fossa depth, anterior joint space, condylar height, and the condyle's horizontal angle (p < 0.05).Regarding the A/N ratio, it showed no significant correlation with the preoperative oral breathing group. Lastly, compared with Pre-OB, Post-OB highlighted a distinct statistical increase in the anterior slope length of the condyle (p < 0.05). A discernible correlation between open-mouth breathing and condylar morphology exists. Continuous open-mouth breathing contributes to adaptive changes in the condylar morphology. Although limited post-operative data suggests that halting open-mouth breathing doesn't immediately result in condylar modifications, a relationship between the two phenomena remains evident.