• 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.46 no.6
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• pp.372-378
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• 2016

Objective: The purpose of the present study was to evaluate the postoperative three-dimensional (3D) changes in the proximal segments after mandibular setback sagittal split ramus osteotomy and to compare the changes between the conventional mini-plate fixation and semi-rigid sliding plate fixation. Methods: Cone-beam computed tomography (CBCT) images were used to evaluate the postoperative 3D changes in the proximal segments during the healing process. CBCT images were superimposed using the symphysis and the lower anterior mandible as references. Results: There were no statistically significant differences between the conventional mini-plate and semi-rigid sliding plate groups (p > 0.05). With respect to the distribution of changes greater than 2 mm in the landmarks, the right condylion, right coronoid process, and left condylion showed ratios of 55.6%, 50.0%, and 44.4%, respectively, in the semi-rigid sliding plate group; however, none of the landmarks showed ratios greater than 30% in the conventional mini-plate group. Conclusions: There were no statistically significant differences in postoperative changes in the segments between the conventional mini-plate and semi-rigid sliding plate groups. Nevertheless, while selecting the type of fixation technique, clinicians should consider that landmarks with greater than 2 mm changes were higher in the semi-rigid sliding plate group than in the conventional mini-plate group.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.6
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• pp.652-657
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• 2000

The kidneys play a vital role in the maintenance of normal body fluid volumes and in the composition of the extracellular fluid compartments. There are normally more than 2 million functioning glomeruli that regulate total body water and solute concentrations. As renal failure progresses, there is a decrease in the number of functioning nephrons. Chronic renal failure(CRF) is the consequence of a multitude of diseases that cause permanent destruction of the nephron. Azotemia is an elevation in blood urea nitrogen(BUN) and serum creatinine levels subsequent to a decreased glomerular filtration rate(GFR), which results in uremia. This loss of renal function can cause functional and metabolic abnomalities of body. For this problem, oral & maxillofacial surgeons have demanded to routinely treat patients with CRF. However, there has not been a reported case of orthognathic surgery by bilateral sagittal split ramus osteotomy(BSSRO) in patients with CRF, which can cause multiple complications in healthy patients. We report developmental mechanism of complication associated with CRF and preop. and postop. care of orthognathic surgery by BSSRO in Cl III patient with severe chronic renal failure.

• The korean journal of orthodontics
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• v.23 no.4 s.43
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• pp.707-724
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• 1993

The purpose of the study is to estimate hard and soft tissue changes after orthognathic surgery for the correction of the mandibular prognathism and to describe interrelationship and ratios of soft and hard tissue changes. The presurgical and postsurgical lateral cephalograms of 31 treated patients(17 males and 14 females) was used ; these patients had received combined orthodontic-surgical treatment by means of a bilateral sagittal split ramus osteotomy. Their ages ranged from 16 to 31 years and mean age was 21.4 years. A computerized cephalometric appraisal was developed and used to analyse linear and angular changes of skeletal and soft tissue profile. The statistical elaboration of the data was made by means of $SPSS/PC^+$. The results of the study were as follows : 1. The correlations of soft and hard tissue horizontal changes were significantly high and the ratios were $97\%$ at LI, $107\%$ at ILS, and $93\%$ at Pog'. 2. The correlations of vertical changes at Stm, LI and horizontal changes at Pog were high$(26\%)$ and at the other areas were not statistically high. 3. The correlations of soft ad hard tissue vertical changes were not significantly high in all areas except Gn' $(30\%)$ and Me' $(56\%)$. 4. The soft tissue thickness was significantly decreased in upper lip and increased in lower lip, and the amount of changes after surgery was reversely correlated with initial thickness. 5. The facial convexity was increased and relative protrusion of upper lip was increased and that of lower lip was decreased. 6. The upper to lower facial height(Gl-Sn/Sn-Me') was increased and upper to lower jaw height(Sn-Stms/Stmi-Me') was increased.

• Journal of The Korean Dental Society of Anesthesiology
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• v.9 no.1
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• pp.24-29
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• 2009

When performing the inferior alveolar nerve block anesthesia, surgeon often faced a difficulty of the surgical operation due to the incomplete anesthesia. One of the reason is the variety of mandibular canal anatomy. Up to now, there are some reports of index cases about bifid mandibular canal among mandibular canal anatomic variation, and some classification is applied according to anatomical location and configuration. When surgical operation is performed involving mandible such as dantal implant treatment, extraction of an impacted third molar, sagittal split ramus osteotomy, etc, the position of mandibular canal should be considered. Bifid mandibular canal clinically causes troublesome cases of anesthesia when inferior alvelor nerve block, especially is performed extraction of an impacted third molar. Therefore, It is important for clinicians to recognize the presence of bifid canals on radiographys. Nowadays, the position of mandibular canal can be measured precisely by using Dental CT. It is not found by panorama image but is found by Dental CT sometimes. Among the patients, which take panorama and Dental CT simultaneously, for tooth extraction of lower impacted third molar in our department, we report the case that did not identifying in panorama but identifying it in Dental CT.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.41 no.5
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• pp.224-231
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• 2015

Objectives: The purpose of this study was to evaluate changes in the pharyngeal airway space and hyoid bone position after mandibular setback surgery with bilateral sagittal split ramus osteotomy (BSSRO) and to analyze the correlation between the amount of mandibular setback and the amount of change in pharyngeal airway space or hyoid bone position. Materials and Methods: From January 2010 to February 2013, a total of 30 patients who were diagnosed with skeletal class III malocclusion and underwent the same surgery (BSSRO) and fixation method in the Division of Oral and Maxillofacial Surgery, Department of Dentistry at the Ajou University School of Medicine (Suwon, Korea) were included in this study. Lateral cephalograms of the 30 patients were assessed preoperatively (T1), immediately postoperatively (T2), and 6 months postoperatively (T3) to investigate the significance of changes by time and the correlation between the amount of mandibular setback and the amount of change in the airway space and hyoid bone position. Results: Three regions of the nasopharynx, oropharynx, and hypopharynx were measured and only the oropharynx showed a statistically significant decrease (P<0.01). A significant posterior and inferior displacement of the hyoid bone was found 6 months after surgery (P<0.01). Analysis of the correlation between the amount of mandibular setback and the amount of final change in the airway space and hyoid bone position with Pearson's correlation showed no significant correlation. Conclusion: In this study, the oropharynx significantly decreased after mandibular setback surgery, and changes in the surrounding structures were identified through posteroinferior movement of the hyoid bone during long-term follow-up. Therefore, postoperative obstructive sleep apnea should be considered in patients who plan to undergo mandibular setback surgery, and necessary modifications to the treatment plan should also be considered.

• Journal of Yeungnam Medical Science
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• v.21 no.2
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• pp.242-250
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• 2004

In general, the skeletal class III has the characteristics of mandibular overgrowth with a normal maxillary growth or maxillary undergrowth with a normal mandibular growth And clinical and radiographic evaluations of the patient are needed. However, the treatment plan is not dependent on these evaluations alone, because patient's general condition and hope for aesthetics varies. The aim of this report is to consider the treatment of a medically compromised patient with an anterior open bite and skeletal class III, which showed a severe mandibular overgrowth. In 2003, a 17-year-old boy with epilepsy, mental retardation presented at our clinic complaining of concave profile. A clinical examination showed severe mandibular prognathism with an anterior open bite. The radiographic examination revealed a short cranial base, a moderate maxillary overgrowth, severe mandibular overgrowth and skeletal open bite tendency. In 2004, he was verified to have no potential of growth by hand-and-wrist radiographs and an endocrine examination. He completed the preoperative orthodontic treatment and orthognathic surgery (sagittal split ramus osteotomy, genioplasty). He was evaluated on the first visit, the preoperative period and the postoperative period with a clinical and radiographic examination. At the first visit, the patient showed moderate overgrowth of the maxilla, severe overgrowth of the mandible, and a subsequential skeletal open bite. After the preoperative orthodontic treatment (preoperative period), the patient showed the same skeletal problem as before and a decompensated dentition for orthognathic surgery. After orthognathic surgery, his profile had improved, but he had still a skeletal openbite tendency because the maxillary orthognathic surgery was not performed. Severe mandibular prognathism with a maxillary overgrowth and anterior open bite should be treated by bimaxillary orthognathic surgery. However, one-jaw orthognathic surgery on the remaining the skeletal open bite tendency was performed for his medical problem and facial esthetics. This subsequential open bite should be resolved with a postoperative orthodontic treatment.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.15 no.3
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• pp.229-237
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• 1993

This study was intended to evaluate a post-operative relapse tendency in mandibular prognathism patients with open-bite. 18 patients with or without open-bite have undergone sagittal split ramus osteotomy and were investigated radiologically with cephalogram. The results were as following 1. The preoperative anterior facial height, mandibular plane angle and mandibular gonial angle were larger in open-bite patients than in nonopen-bite patients.(p>0.05) 2. There was significant correlation between surgical change of SNA, mandibular plane length and long-term relapse.(p<0.01). 3. There was relatively stable postoperative anterior facial height in open bite patients. 4. There was no significant correlation between the surgical change of mandibular plane angle, amount of mandibular setback and long-term relapse.(p>0.01) 5. This study showed that horizontal relapse was more significant than vertical relapse.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.37
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• pp.38.1-38.6
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• 2015

Background: The posterior movement of mandible was known as the main cause of the changes in the pharyngeal airway space (PAS) and the postoperative obstructive sleep apnea (OSA). The purpose of this study was to know the changes of PAS and position of hyoid bone. Methods: Lateral cephalographies of 13 patients who had undergone sagittal split ramus osteotomy (SSRO) setback surgery were taken preoperatively (T1), postoperatively within 2 months (T2), and follow-up after 6 months or more (T3). On the basis of F-H plane, diameters of nasopharynx, oropharynx, and hypopharynx were measured. The movements of the soft palate, tongue, and hyoid bone were also measured. Results: The amount of mandible setback was $7.5{\pm}3.8mm$. In the measurements of PAS, there was a statistically significant decrease of $2.8{\pm}2.5mm$ in nasopharynx (P < 0.01), and $1.7{\pm}2.4mm$ in oropharynx (P < 0.01) were observed after surgery. The hypopharynx decreased $1.0{\pm}2.1mm$ after surgery and continuously decreased $1.0{\pm}2.8mm$ at follow-up. The changes in hyoid bone position showed the posterior movement only after surgery and posteroinferior movement at follow-up. Conclusions: The PAS such as nasopharynx, oropharynx, and hypopharynx showed relatively high correlation with the amount of mandibular setback. The change of resistance in upper airway may be important for the prevention of OSA after mandibular setback surgery.

• The korean journal of orthodontics
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• v.45 no.1
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• pp.3-12
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• 2015

Objective: We compared the skeletal and dental changes that resulted from the use of two methods of intermaxillary fixation (IMF)-miniscrews and surgical archwire-in 74 adult patients who had Class III malocclusion and were treated with the same orthognathic surgical procedure at a hospital in Korea. Methods: All the patients underwent Le Fort I osteotomy and bilateral sagittal split ramus osteotomy with rigid fixation. They were divided into two groups according to the type of IMF used-group 1 underwent surgical archwire fixation and group 2 underwent orthodontic miniscrew fixation. In a series of cephalograms for each patient, we compared vertical and horizontal tooth-position measurements: (a) immediately after surgery ($T_0$), (b) 3 months after surgery ($T_1$), and (c) 6 months after surgery ($T_2$). Cephalometric changes within each group were examined using one-way analysis of variance (ANOVA) while the independent samples t -test procedure was used to compare the two groups. Results: After surgery, the maxillary incisors tended to be proclined in both groups although there were no significant differences. Incisor overbite increased significantly in both groups from $T_0$ to $T_1$, and the miniscrew group (group 2) showed slightly greater overbite than the archwire group (group 1). Conclusions: This study suggest that the use of orthodontic miniscrews and orthodontic surgical archwire for IMF in adult patients results in similar skeletal and dental changes.