Objective To evaluate the effect of orthodontic combined with prosthetic therapy on dental function and oral health in patients with dentition defect and dentofacial deformity. Methods 120 patients admitted to Shanyang County Traditional Chinese Medicine Hospital from February 2021 to February 2024 were randomized into routine group (prosthesis alone) and study group (orthodontics + prosthesis). Masticatory efficiency, bite force, periodontal probing depth, gingival index, and complications were compared. Results After treatment, the study group showed significantly higher masticatory efficiency and bite force, and lower probing depth, gingival index, and complication rate than the routine group (P < 0.05). Conclusion Orthodontic combined with prosthetic therapy effectively improves masticatory function and periodontal health, and reduces complications in these patients.