• Maxillofacial Plastic and Reconstructive Surgery
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• v.42
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• pp.27.1-27.9
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• 2020

Background: Mandibular setback surgery can change the position of the mandible which improves occlusion and facial profile. Surgical movement of the mandible affects the base of the tongue, hyoid bone, and associated tissues, resulting in changes in the pharyngeal airway space. The aim of this study was to analyze the 3-dimensional (3D) changes in the hyoid bone and tongue positions and oropharyngeal airway space after mandibular setback surgery. Methods: A total of 30 pairs of cone-beam computed tomography (CBCT) images taken before and 1 month after surgery were analyzed by measuring changes in the hyoid bone and tongue positions and oropharyngeal airway space. The CBCT images were reoriented using InVivo 5.3 software (Anatomage, San Jose, USA) and landmarks were assigned to establish coordinates in a three-dimensional plane. The mean age of the patients was 21.7 years and the mean amount of mandibular setback was 5.94 mm measured from the B-point. Results: The hyoid bone showed significant posterior and inferior displacement (P < 0.001, P < 0.001, respectively). Significant superior and posterior movements of the tongue were observed (P < 0.05, P < 0.05, respectively). Regarding the velopharyngeal and glossopharyngeal spaces, there were significant reductions in the volume and minimal cross-sectional area (P < 0.001). The anteroposterior and transverse widths of the minimal cross-sectional area were decreased (P < 0.001, P < 0.001, respectively). In addition, the amount of mandibular setback positively correlated with the amount of posterior and inferior movement of the hyoid bone (P < 0.05, P < 0.05, respectively). Conclusion: There were significant changes in the hyoid bone, tongue, and airway space after mandibular setback surgery.

• The korean journal of orthodontics
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• v.42 no.6
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• pp.318-328
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• 2012

Objective: To assess the position and movements of the hyoid bone during deglutition in patients with open bite. Methods: Thirty-six subjects were divided into 2 groups according to the presence of anterior open bite. The open bite group (OBG) and control group each comprised 18 patients with a mean overbite of $-4.9{\pm}1.9$ mm and $1.9{\pm}0.7$ mm. The position of the hyoid bone during the 4 stages of deglutition was evaluated by measuring vertical and horizontal movement of the bone. Results: Interactions of group and stage showed no significant effect on the measurements (p > 0.05). However, when group and stage were evaluated individually, they showed significant effects on the measurements (p < 0.001). In OBG, the hyoid bone was more inferiorly and posteriorly positioned, and this position continued during the deglutition stages. Conclusions: The hyoid bone reaches the maximum anterior position at the oral stage and maximum superior position at the pharyngeal stage during deglutition. Open bite does not change the displacement pattern of the bone during deglutition. The hyoid bone is positioned more inferiorly and posteriorly in patients with open bite because of released tension on the suprahyoid muscles.

• Journal of Yeungnam Medical Science
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• v.5 no.2
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• pp.71-77
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• 1988

This study was made to investigate the influence of mouth breathing to tongue, mandible and hyoid bone position. It has been clinically suggested that the mouth breathing is induced by the respiratory dysfunction of nasopharyngeal airway causing by the Adenoids. The author used the 50 children, who were the nasal breathes with normal occlusion as the control group, and 50 children, who were mouth breathers with Adenoid as the experimental group. Results were as following: 1. In experimental group, the tongue was positioned more anterior and lower than that of the normal children. 2. In experimental group, the mandible was positioned more lower than that of the normal children. 3. In experimental group, the hyoid bone was positioned more anterior and lower than that of the normal children.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.2
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• pp.164-171
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• 2000

Purpose : This study was aimed at measuring the changes in the hyoid bone position, tongue position, and pharyngeal airway space in subjects with mandibular setback osteotomies. Methods : Twenty patients were evaluated retrospectively for their changes in pharyngeal airway space, tongue and hyoid bone positions. All patients underwent surgical mandibular setback using bilateral sagittal split osteotomies. The cephalometric analysis was performed preoperatively, and 1 week, 3-6 months, and 1 year postoperatively. Result : The hyoid bone moved inferiorly and posteriorly immediately after surgery, and it returned to the preoperative position during follow-up period. The nasopharyngeal airway space was not significantly changed after surgery. A considerable decrease in the oropharyngeal and hypopharyngeal airway spaces following mandibular setback surgery was found. The upper and lower tongue was posteriorly repositioned immediately after surgery. During follow-up period, the hypopharyngeal airway space and lower tongue posture returned to the preoperative positions, but the oropharyngeal airway space and upper tongue posture were not significantly changed. The position of pogonion remarkably changed to backward immediately after surgery, but slightly anterior advancement was found during follow-up period. Conclusion : Immediately after mandibular setback surgery, the oropharyngeal and hypopharyngeal airway spaces obviously decreased due to posterior and inferior repositions of the tongue and hyoid bone. During follow-up period, lower tongue and hyoid bone returned to the preoperative positions, it was related to advancement of the pogonion in this period. The narrowing of the oropharyngeal airway space and posterior movement of the upper tongue posture were relatively permanent after mandibular setback surgery. We suspected this phenomenon had an influence on maintaining the total volume of oral cavity against mandibular setback.

• The korean journal of orthodontics
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• v.26 no.6
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• pp.677-689
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• 1996

• The korean journal of orthodontics
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• v.28 no.4 s.69
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• pp.499-515
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• 1998

The purpose of this study was to examine the associations of head posture the position of the tongue or the hyoid bone to craniofacial structure. Cephalograms taken in Natural head position(NHP) of 90 dental students (50 in male, 40 in female, 20 to 30 years in age) were traced and measured using the extracranial true horizontal and vertical lines. The obtained results were as follows; 1. There was no sex difference in head posture, but the hyoid bone was placed anteroinferiorly in male more than in female and anteroinferior inclination of the hyoid bone showed greatly in male. 2. The more inclined was the cervical column, the less prognathic was the face in natural head posture, and the larger cervical curvature, the more vertical pattern of the face. 3. The less small showed craniocervical angulation, the more anteriorly placed was the hyoid bone to the cranial base, and there was no significantly association between craniocervical angulation and the vertical position of the hyoid bone. 4. The more prognathic was the mandible, the more anteriorly placed was the hyoid bone, and there was slightly association between the craniofacial morphology and the vertical position of the hyoid bone.

• The korean journal of orthodontics
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• v.26 no.3
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• pp.247-254
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• 1996

This study was performed to evaluate the hyoid bone position and airway in skeletal class III malocclusion and to prove the correlation between airway, hyoid bone position and mandibular position. The sample, considered of 47 class III malocclusion patients for experimmtal group and 52 class I malocclusion students for control group. Twenty three linear and angular measurements about hyoid bone position, airway size, mandibular position were taken from the lateral cephalograms. The differences between skeletal class III malocclusion group and normal occlusion group were compared and the correlation were evaluated statistically. The results obtained were as follows, 1. There were significant difference in S-APH, A-APH, N-APH, LAH-PBR, AA-PNS, PNS-ad between class I and class III malocclusion groups. 2. The hyoid bone was more anteriorly positioned in class III malocclusion group than class I malocclusion group and skeletal airway size in class III malocclusion group was smaller than class I malocclusion group. 3. There were significant difference in several measurements especially vertical and angular measurements of hyoid bone position and airway size between male and female. Usually the measurements in male were larger than female. 4. There were no significant correlation between hyoid bone position and airway size also airway size, and didn't showe significant correlation with mandibular position, 5. S-APH showed negative correlation with Wits appraisal and A-APH, N-APH showed positive correlation with Wits appraisal. On the contrary vertical measurements of hyoid bone position showed positive correlation with lower facial height.

• The korean journal of orthodontics
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• v.20 no.1
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• pp.197-207
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• 1990

This comparative study was undertaken to investigate the position of the hyoid bone in unilateral cleft lip and palate individuals. The materials for this study consisted of 35 subjects with surgically repaired unilateral cleft lip and palate (25 males, 10 females) and 40 subjects with normal facial morphology (20 males, 20 females). Cephalometric measurements of unilateral cleft and palate individuals were compared with those of non-cleft individuals. The conclusions of this study were obtained as follows: 1. To the anterior cranial base, the hyoid bone in unilateral cleft lip and palate individuals was located downward as compared with non-cleft individuals. 2. To the mandible, the hyoid bone in unilateral cleft lip and palate individuals was located backward as compared with non-cleft individuals. 3. The distance between the dorsum of the tongue and the inferior border of the hard palate in unilateral cleft lip and palate individuals was longer than that in non-cleft individuals. 4. Unilateral cleft lip and palate individuals showed no significant difference in the distance between the hyoid bone and the dorum of the tongue as compared with non-cleft individuals.

• Archives of Plastic Surgery
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• v.43 no.4
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• pp.374-378
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• 2016

Submandibular gland ptosis is a common impediment to obtaining superior surgical aesthetic results in neck lift surgery. Techniques for suspending the submandibular gland have been proposed, but these procedures have the drawbacks of disturbing the floor of the mouth mucosa and periosteum. We present an approach of submandibular gland suspension for the treatment of gland ptosis by employing a platysma and hyoid bone fascia cradle. Our technique was performed on cadaveric models. The platysma muscle and hyoid bone cradle for submandibular gland ptosis was created on the left side of the neck in two cadavers. A submental incision with sharp dissection was performed to raise a supraplatysmal flap. A subplatysmal plane was developed until the submandibular gland was identified. Sutures were used to pexy the platysma to the hyoid bone periosteum and deep cervical fascia, tightening the overlying muscle and in turn elevating the submandibular gland. Submandibular gland ptosis must be corrected in order to achieve exemplary aesthetic results. Our approach of creating a cradle with the platysma and hyoid bone avoids the potential complications of previously described sling procedures, while still maintaining the integrity of the gland and surrounding tissues.

• The korean journal of orthodontics
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• v.16 no.2
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• pp.99-106
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• 1986

The author studied 21 adenoid hypertrophied children and 50 normal children by the horizontal, vertical and angular measurements to analyze, the effects of the lymphadenoid hypertrophy to the tongue, mandible, and hyoid bone position. The results were as follows; 1. The tongue of the Adenoid hypertrophy children was positioned mon anterior and lower than that of the normal children. 2. The horizontal, vertical, and angular measurements of the mandible position were larger in the experimental group and especially ANS to ME, PNS to MP, PTM to MP, PP to MP, FOP to MP showed statistically significant difference. 3. The measurements of the hyoid bone position were also larger in the experimental group.