• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.4
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• pp.294-305
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• 2009

Purpose: This retrospective study evaluated the changes in hyoid bone and tongue positions as well as oral cavity volume after mandibular setback by BSSRO. Materials and Methods: 18 Koreans who underwent BSSRO to correct mandibular prognathism were studied. Lateral cephalograms were taken and traced preoperatively (T0), immediately (T1) and approximately 6 months postoperatively (T2). Submentovertex radiograghs were taken and traced before surgery (T0) and about 6 months after surgery (T2). The area and volume of oral cavity, the vertical and horizontal dimensions of the hyoid bone and tongue dorsum were measured. Results: Mandibular setback surgery resulted in a significant reduction of lower oral cavity volume. The hyoid bone displaced posteroinferiorly immediately after surgery, and it tended to return to its original vertical position at 6 month after mandibular setback by BSSRO. The retropalatal space around tongue was maintained and the retrolingual space around tongue was reduced immediately postoperatively. The readaptation of tongue was not evident for that the follow up period was not long enough. No significant statistical correlations between the amounts of mandibular setback and the changes of oral cavity volume were observed. Conclusion: Mandibular setback surgery resulted in a significant reduction of lower oral cavity volume, which was most likely attributable to the posterior movement of the mandible. More subjects and long-term observations should be performed to assess the changes of oropharyngeal configuration following mandibular setback surgery.

• The korean journal of orthodontics
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• v.19 no.2
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• pp.130-143
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• 1989

The purpose of this study was to assess the early effect of FR III on the growing patients with anterior cross-bite. The lateral cephalograms and models were obtained from 7 patients at the time of pretreatment and correction of anterior cross-bite. The results were as follows: 1. A slight tendency of rotation toward anterosuperior direction and the growth to anterior direction were shown in maxilla. 2. There were a little change of mandibular vertical position and increase in lower facial height although some variations existed. 3. The bodily or labial tipping movement was shown in maxillary incisors. 4. The lingual tipping of mandibular incisors was shown in all cases. 5. Maxillary arch width increased while mandibular arch width usually changed a little although some variations existed. But it was difficult to summary in a word because variable responses were noted according to a wide variety of skeletal type, growth, and malocclusion.

• The korean journal of orthodontics
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• v.21 no.1 s.33
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• pp.131-170
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• 1991

This study was designed to analyze morphological characteristics of Korean young adults, norms and standard deviation of variables, sexual differences, correlationship between each area of face and correlationship between hard tissue and soft tissue. The primary sample consisted of 45 males and 57 females who were early and middle twenties and had acceptable profile, no history of previous orthodontic treatment, absence of remarkably large overjet and overbite, full complement of permanent teeth, Class I skeletal and dental relationships and good vertical facial proportions. Their cephalograms were analyzed morphologically with a computer morphometrics. Then the final sample - 25 males and 38 females - were selected within 1 S.D. of E-line, ANB, P/A facial height ratio, Interincisal angle, L1 to A-Pog, ODI and APDI. The results of the study were as follows: 1 In the form and proportion of facial skeleton there were no significant differences between males and females, but in the size males were larger than females. 2. The dental protrusion patterns had no significant sexual difference and no significant correlationship between protrusion of upper lip and inclination of upper incisor. But mentolabial angle had positively correlated with interincisal angle and negatively with inclination of upper and lower incisor. 3. In the relationship between nose and soft-tissue profile, males were larger than females in nasal length, height and angular measurements. 4. In analysis of soft-tissue profile, males were larger than females in the length and thickness. In the angular measurements and proportion of soft-tissue profile, there were no significant differences between males and females.

• The korean journal of orthodontics
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• v.21 no.1 s.33
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• pp.223-238
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• 1991

This study was carried out in order to findout the amount of tooth movement, the changes arch size and the changes in arch morphology following orthodontic treatment and to provide a guideline for to predict post-treatment arch morphology. The sample group for this study consists of 15 males and 22 females, totalling in 37 persons, who received orthodontic treatment at Orthodontic Department of Dankook Univ. Dental Hospital. They are classified into Extraction Class I treatment group (E I), Non-extraction Class I treatment group (N I), and Non-extraction Class III treatment group (N III), according to their pre-treatment malocclusion state and methods of treatment. Following conclusions and averaged dental arch form for each group were obtained by cephalometric linear measurements and dental arch measurements using pre- and post-treatment lateral cephalograms and plaster study models. 1. Intercanine width were reduced in max. of both EI and NI during the period of treatment, 2. Intermolar width were reduced in max. of EI and increased in max. of NI. Therefore although there was no difference between these two groups before the treatment, intermolar width of the max, of NI was wider than that of E1 after the treatment. 3. PMV-incisor distance and PMV-canine distance were decreased in both max. and mand. of EI and that of NI, during the period of treatment. PMV-molar distance was decreased in both max. and mand. of NI and in mand. of NIII. 4. Items that showed stability during the treatment were: max. & mand. PMV-molar distance, mand. intercanine and intermolar width in EI; mand. intercanine and intermolar width in NI; mand. & max. PMV-incisor distance, PMV-canine distance, max. PMV-molar distance and max. & mand. intercanine and intermolar width in NIII. 5. The differences in averaged canine and molar variances to post-treatment dental arch form were present only in EI and in NI. There was no variance between maxilla and mandible in each group.

• The korean journal of orthodontics
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• v.32 no.3 s.92
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• pp.155-163
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• 2002

This study was performed to assess the accuracy of computer-based treatment prediction for soft tissue profile using Quick Ceph Image $Pro^{TM}\;&\;Quick\;Ceph\;2000^{TM}$ in bimaxillary protrusion cases. The Ore- and post-treatment lateral cephalograms of 21 female adults treated by low first premolar extraction were imaged and 9 landmarks and 27 specific soft tissue mesurements were digitized for comparing actual treatment results with computer simulations. The results of this study showed that Quick Ceph Image $Pro^{TM}\;&\;Quick\;Ceph\;2000^{TM}$ tends to overestimeate horizontal changes and underestimate vertical changes. In the computer simulation, upper lip showed rolling tendency. The upper lip measurements were disposed to be regular direction hut lower lip measurements were varied case by case even if it was statistically insignificant.

• The korean journal of orthodontics
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• v.31 no.4 s.87
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• pp.439-445
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• 2001

The Purpose of this study was to compare the dento-skeletal characteristics between functional and skeletal anterior cross-bite patients. Twenty-eight functional anterior cross-bite patients and thirty-one skeletal anterior cross-bite patients were selected as a test and a control group. Mean ages of the test and the control group were $9.6{\pm}1.8$ and $9.9{\pm}1.9$, respectively. Lateral cephalograms were taken. Forty-nine cephalometric variables were measured and statistical analysis was performed to find the morphological differences between the groups. Statistically significant differences were found in the cephalometric variables of cranial deflection, maxillary depth, ANB, convexity, NPo-AB, APDI, Mx 1-SN, Mx 1-NA angle, Mx 1-NA, Md 1-NB angle and Md 1-NB. The test group showed more Class III growth potential, more protruded maxilla, lesser maxillo-mandibular difference, more uprighted and retruded maxillary central incisor, more labially tipped and protruded mandibular central incisor.

• The korean journal of orthodontics
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• v.29 no.4 s.75
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• pp.503-510
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• 1999

The purpose of this study is to investigate the negative effects of cervical pull headgear and to compare the differences between the two groups of growers-vertical grower and horizontal grower group-which are classified by the posterior-anterior facial height ratio. Initial and final lateral cephalograms were taken for 26 patients including 15 vertical growers and 11 horizontal growers ; also, 3 angular measurements and 4 linear measurements were evaluated. The following results were found. 1. The palatal plane was tipped anteroinferiorly in the vertical grower group. 2. The posterior facial height/anterior facial height ratio was increased in the horizontal grower group. 3. The Mandibular plane angle remained stable on both groups. 4. There was no significant difference between the two groups in the amount of maxillary molar extrusion.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.28 no.1
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• pp.24-30
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• 2002

The facial patterns were expressed by the interrelation of variable factors such as heredity, function and environment. Such variable factors have an effect on the growth and development of maxillofacial bones. The malocclusions with skeletal discrepancies are caused by abnormal forms, sizes and positions of cranial base, maxilla and mandible. For the proper diagnosis and treatment planning, the analysis of such structures is necessary. Lateral cephalograms of 54 adults with class III malocclusion patients (test group) and 61 adults with normal occlusion (control group) were analyzed. Anteroposterior relations and sizes of cranial base, maxilla, mandible were estimated to compare with those of normal ones. In test group, the anterior cranial base length was within normal range, but posterior cranial base, maxilla and mandibular body were longer than those in control group, significantly. Based on the cranial base, the location of maxilla in test group was normal, but the location of mandible was more anterior than that in control. Based on the maxilla, the location of mandible was more anterior in test group than that in control. Both mandibular body and ramus anteroposterior lengths in test group were larger than those in control. Both mandibular plane angle and upper gonial angle were within normal range, but lower gonial angle was significantly high in test group.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.40 no.4
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• pp.160-168
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• 2014

Objectives: The purpose of this study was to evaluate the condylar position in relation to the glenoid fossa before and after orthodontic-orthognathic surgical treatment and to investigate the relationship with skeletal relapse. Materials and Methods: Lateral cephalograms and temporomandibular joint tomograms from 19 patients with mandibular prognathism who received orthodontic-orthognathic surgery were included in this study. Samples were divided into two groups based on skeletal change during the retention period. The relapse group consisted of 7 patients (3 females and 4 males; mean age, 21.9 years) whose pogonion or menton displaced more than 1 mm during the retention period and the stable group consisted of 12 patients (5 females and 7 males; mean age, 21.7 years). Anterior joint space, posterior joint space, superior joint space, and anteroposterior index were measured on tomograms at pretreatment and posttreatment timepoints. Condyle position and frequency of the positional change were compared between both groups. Results: In the relapse group and stable group, 42.9% and 45.8% of the condyles, respectively, showed forward or backward displacement at posttreatment. However, the changes were small and the mean anterior, posterior, superior joint spaces and frequencies of the positional changes did not differ statistically between both groups. Conclusion: Our results suggest that small positional changes of the condyle, which may occur after orthodontic-orthognathic surgery treatment, may not be related to skeletal relapse after removal of the orthodontic appliances.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.28 no.1
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• pp.27-34
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• 2006

After orthognathic surgery in skeletal class III patients, the hyoid bone position and the upper airway dimension could be changed due to mandibular setback. There has been many studies about airway dimension of the patients with skeletal class II malocclusion or obstructive sleep apnea. but not with skeletal class III. The purpose of this study was to examine the change of position of the hyoid bone and the consequent change of airway space as the result of retrusion of mandible after orthognathic surgery in skeletal Cl III malocclusion patients. It is also to apply this results in predicting, diagnosing and treating the subsequent obstructive sleep apnea. Forty patients who were diagnosed as skeletal Cl III maloccusion, received orthoganthic surgery of both jaws including mandibular setback, and were followed up post-operatively for more than 6 months were selected. There were 10 male patients 30 female patients. The preoperative and postoperative lateral cephalograms were traced and the distances and angles were measured. The nasopharyngeal space increased postoperatively while the oropharyngeal space decreased. Except for the change of oroparyngeal space, the changes in male patients were greater than female patients. The hyoid bone moved in the posterior-inferior direction, and the change was greater in males than in females. If the postoperative mandibular setback is great, then a significant decrease of airway space and posterior and inferior movement of the hyoid bone were observed. This can result in symptoms related to obstructive sleep apnea. This result should be considered in the diagnosis and treatment planning of orthognathic surgery patients.