To investigate short- and long-term three-dimensional changes of pharyngeal airway morphology and hyoid bone position in dento-skeletal class III deformity patients after 2-jaw orthognathic surgery with segmentation.
A retrospective analysis has been performed on patients with dento-skeletal class III deformity who had undergone orthognathic 2-jaw surgery with segmentations, presenting both pre- and post-surgical cone-beam computed tomographys. Three-dimensional skeletal movements, pharyngeal airway changes and hyoid bone position were measured and correlated.
The mean short term postsurgical review period for all included 47 patients was 5.8 ± 2.2 months. Thirteen patients among them provided a mean long term period of 26.4 ± 3.4 months. The mean postsurgical maxillary movement was 2.29 ± 2.49 mm in vertical, 2.02 ± 3.45 mm in horizontal direction, respectively, while the mandibular movement was 6.49 ± 4.58 mm in vertical, and −5.85 ± 6.13 mm in horizontal direction. In short-term, the vertical length of nasopharynx was found to be reduced (P = 0.005) but increased for the oropharynx (P < 0.001). Furthermore, the oropharyngeal minimum cross-sectional area has decreased significantly (P = 0.013). The hyoid bone moved posterosuperiorly, however, with only its horizontal movement found to be significant (P = 0.043). No significant result was detected in long-term analyses, neither in postsurgical pharyngeal airway changes nor the hyoid bone movement. There were no significant differences in pharyngeal airway measurements (P > 0.05) detected between patients with and without genioplasty advancement.
Two-jaw orthognathic surgery in dento-skeletal class III patients led to a statistically non-significant reduction of the post-surgical airway volume in both short- and long-term. Although the post-surgical oropharyneal minimum cross-sectional area was decreased significantly in the short term, this finding did not persist in the long term.
*Center of Oral & Maxillofacial Surgery Studies, Faculty of Dentistry, Jalan Hospital, Selangor Darul Ehsan, Malaysia
†Discipline of Oral and Maxillofacial Surgery, Faculty of Dentistry, The University of Hong Kong
§Discipline of Periodontology, Faculty of Dentistry, The University of Hong Kong, Prince Philip Dental Hospital, Hong Kong, China.
Address correspondence and reprint requests to Roger A. Zwahlen, MD, DMD, Private Practice, Grand-Places 16, Fribourg, Switzerland; E-mail: email@example.com
Received 17 May, 2018
Accepted 23 December, 2018
The research was supported by the General Research Fund through the Research Grants Council of Hong Kong SAR (project number: HKU 17121915).
The authors report no conflicts of interest.