EVALUATION OF CERVICAL SPINE POSTURE AFTER FUNCTIONAL THERAPY WITH HERBST APPLIANCE

Abstract

Objective: To evaluate changes in cervical spine posture and hyoid bone position following functional therapy with the Herbst appliance in patients with skeletal Class II malocclusion.

Methodology: This was an experimental descriptive study conducted at Department od Orthodontics, Nishtar Institute of Dentistry, Multan from June 2023 to December 2023 on 34 patients diagnosed with skeletal Class II malocclusion in Cervical Vertebral Maturation Index (CVMI) stages III and IV. Pre- and post-treatment lateral cephalograms were analyzed to assess changes in hyoid bone position (H-SN, H-FH, H-MP, H-C3) and cervical spine posture (SN-OPT, PP-OPT, MP-OPT, SN-CVT, PP-CVT, MP-CVT, OPT-CVT). Measurements were done manually using acetate sheet tracing.

Results: The mean age of patients was 12.7 ± 1.5 years, with 52.94% females and 73.53% in CVMI stage IV. Significant post-treatment changes were observed in all measured cervical and hyoid parameters except H-SN (p = 0.994). Angles like SN-CVT, PP-CVT, and MP-CVT showed the most pronounced changes, with mean increases of -16.91°, -16.76°, and -17.94°, respectively (p < 0.001). These findings reflect anterior displacement of the hyoid bone and vertical realignment of cervical structures.

Conclusion: Herbst appliance therapy leads to notable improvements in cervical spine posture and hyoid positioning in growing Class II patients. These outcomes support its use as a functional orthopedic modality that exerts favorable effects beyond dental correction, with implications for musculoskeletal balance and posture.