• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.2
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• pp.109-113
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• 2007

Introduction. In patients with mandibular prognathism, Bilateral Sagittal Split Ramus Osteotomy(BSSRO) combined with orthodontic treatment reduces oral volume and influences tongue and other surrounding tissues. Purpose of this study was to analyze post-operative tongue position and airway dimension, as well as mandibular changes in vertical, horizontal, and angular dimensions. Materials and methods. Height of dorsum of tongue, width of airway, gonial angle and lower facial height of mandibular prognathic patients who visited Kangdong Sacred Heart Hospital from Jan. 2001 to Dec. 2006 were anaylzed via pre-operative and post-operative cephalograms. T-test was used to compare pre-operative and post-operative measurements. Also, correlations among pre-operative measurements of the patients were analyzed. Results and conclusion. A significant correlation was shown between ANS-Xi-PM area and location of dorsum of tongue in pre-operative patients. A significant superior movement of tongue and decrease of airway width was observed in post-operative patients. Also the upper gonial angle decreased significantly.

• The korean journal of orthodontics
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• v.22 no.1
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• pp.67-88
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• 1992

The purpose of this study was to investigate the changes of mandibular movement and muscle activity following orthognathic surgery in patients with mandibular prognathism. Lateral cephalogram, M.K.G., E.M.G. recordings were obtained immediately before surgery, and 2 months and 8 months after surgery. Among the patients who received orthognathic surgery, 19(13 men, 6 women) were selected for this study. Statistical analysis for each time interval differences were performed with the SPSS package. The results were as follows: 1. Compared with the pre-operative group (opening 349.7mm/sec, closing 313.1mm/sec), the mean values of the maximum opening and closing velocity in the skeletal Class III surgery group were significantly decreased in the 2 months post-operative (opening 232.9mm/sec, closing 206.9mm/sec), but the values tended to increase in the 8 months post-operative group (opening 280.9 mm/sec, closing 319.1mm/sec). 2. Compared with the pre-operative group (61.7 mm/sec), the maximum velocity of the terminal tooth contact increased in the 2 months (72mm/sec) and 8 months (105.7mm/sec) postoperative groups. 3. In the mean value of vertical freeway space, there was significant difference between the normal group and the pre-operative group, but not between the normal group and the 8 months post-operative group. 4. In the mean values of the maximum opening, the maximum anterio-posterior movement from centric-occlusion, and the lateral deviation from centric occlusion, there was no significant difference between the normal group and the surgery group (the pre-operative and the 8 months post-operative groups). 5. The mature swallowing pattern was 58% in the pre-operative group, but 90% in the 2 months post-operative group, and 63% in the 8 months post-operative group. 6. In the comparison of muscle activity, there was no significant difference between the normal group and the surgery group during the rest position. However, during cotton roll clenching, there was significant difference between the normal group and the pre-operative group, but not between the normal group and the 8 months post-operative group.

• Journal of Dental Rehabilitation and Applied Science
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• v.32 no.1
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• pp.70-79
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• 2016

Patients who lost posterior teeth due to periodontitis or dental caries have collapsed vertical dimension, unstable occlusion and change of the mandibular position. In particular, patients in orthognathic surgery, clinician should re-establish the pre-operative stable position of mandibular condyle in articular fossa and favorable vertical dimension for high post-operative stability of mandible. Therefore, interdisciplinary approach and co-operation, including prosthetics, orthodontics, oral and maxillofacial surgeon, from diagnosis and treatment plan is important to get a good outcome. This case report was patients who had collapsed occlusal plane due to severe dental caries on maxillary molars with skeletal Class III malocclusion. Before orthognathic surgery, resetting of maxillary occlusal plane with temporary removable denture was performed. Then successful multidisciplinary approach was done and lead to acceptable clinical outcome.

• The korean journal of orthodontics
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• v.35 no.4 s.111
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• pp.320-329
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• 2005

The three-dimensional (3D) changes of bone, soft tissue and the ratio of soft tissue to bony movement was investigated in 8 skeletal Class III patients treated by mandibular setback surgery. CT scans of each patient at pre- and post-operative states were taken. Each scan was segmented by a threshold value and registered to a universal three-dimensional coordinate system, consisting of an FH plane, a mid-sagittal plane, and a coronal plane defined by PNS. In the study, the grid parallel to the coronal plane was proposed for the comparison of the changes. The bone or soft tissue was intersected by the projected line from each point on the gird. The coordinate values of intersected point were measured and compared between the pre- and post-operative models. The facial surface changes after setback surgery occurred not only in the mandible, but also in the mouth corner region. The soft tissue changes of the mandibular area were measured relatively by the proportional ratios to the bone changes. The ratios at the mid-sagittal plane were $77\~102\%(p<0.05)$. The ratios at all other sagittal planes had similar patterns to the mid-sagittal plane, but with decreased values. And, the changes in the maxillary region were calculated as a ratio, relative to the movement of a point representing a mandibular movement. When B point was used as a representative point, the ratios were $14\~29\%$, and when Pog was used, the ratios were $17\~37\%(9<0.05)$. In case of the 83rd point of the grid, the ratios were $11\~22\%(p<0.05)$.

• The Journal of the Korean dental association
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• v.50 no.2
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• pp.72-82
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• 2012

Recently in treatment planning for orthognathic surgery, 3-dimensional analysis using CBCT can give more detailed information that cannot be achieved with 2-dimensional cephalograms. Also, laser Scanning and 3D camera can show 3-dimensional information on soft tissue changes as well as hard tissue changes in orthognathic surgery patients. In other words, soft tissue changes in lateral facial area as well as mid facial area can be quantitatively calculated. To bring out the best results from orthognathic surgery, close interaction between orthodontist and oral surgeon is needed and well treated pre-surgical orthodontics can simplify orthognathic surgical plan that also results in good long-term stability. In surgery-first cases, more thoughtful diagnosis and pre-operative preparation will be needed to prevent complicated problems.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.4
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• pp.289-300
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• 2001

Telomerase is a ribonucleoprotein that synthesizes telomere repeats. It has been reported that activation of telomerase was associtated with immortalization, proliferative activity and carcinogenesis. Recently, telomerase activity has been extensively studied in many kinds of malignant tumors for clinical diagnostic and/or prognostic utilities. In neuroblastoma, breast carcinoma, gastric carcinoma, non-small cell lung carcinoma, close relationship has been reported between high telomerase activity and lymph node metastasis, tumor aggressiveness and poor prognosis. The purpose of this study is to investigate the clinical implication of telomerase activity assay as an adjunctive factor in decision-making on neck node management, speedy pre-operative judging on histologic malignancy grading. Thus we performed semi-quantitative assay of telomerase activity using Telomerase PCR ELISA $kit^{(R)}$(Boeringer Manheim, Germany) and evaluated correlation between telomerase activity and tumor size, neck node metastasis, Anneroth malignancy score and influence of pre-operative chemotherapy on its activity in 27 cases of oral squamous cell carcinomas and 18 cases of normal oral epithelium. Also, correlation between telomerase activities and PCNA indices was evaluated. The results were obtained as follows: 1. The telomerase activities were detected in 24 specimens out of 27 oral squamous cell carcinoma specimens (88.9%) and in 5 specimens out of 18 normal oral epithelium specimens (27.8%). The mean value of telomerase activities was $0.9793{\pm}0.3428$ in 24 oral squamous cell carcinoma specimens and $0.4855{\pm}0.1117$ in 5 normal oral epithelium specimens. The positivity rate and mean value of telomerase activities in oral squamous cell carcinoma specimens were significantly higher than those of normal oral epithelium specimens (p<0.05). 2. There was no significant correlation between total Anneroth malignancy score and telomerase activity (p>0.05), but points of mitosis index and depth of invasion were significantly correlated with telomerase activities (p<0.05). 3. The positive immunohistochemical staining for PCNA(proliferating cell nuclear antigen) was observed in 26 specimens out of 27 oral squamous cell carcinoma specimens and mean value of PCNA indices of 26 specimens was $53.67{\pm}26.46$. PCNA indices were significantly correlated with telomerase activities (p<0.05). 4. The mean value of telomerase activities was significantly higher in pathologic T3/T4 group than in T1/T2 group (p<0.01). There was no significant difference of mean value of telomerase activities between pathologic neck node positive group and negative group (p> 0.05). Pre-operative chemotherapy significantly lowered the telomerase activities (p<0.05). The above results suggested telomerase activity could be used as diagnostic marker and adjunctive parameter for judging on histologic malignancy in oral squamous cell carcinoma.

• The korean journal of orthodontics
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• v.39 no.2
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• pp.72-82
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• 2009

Objective: The purpose of this study was to investigate the structural changes of the hyoid bone and upper airway after orthognathic surgery for skeletal class III anterior open bite patients, and make comparisons with normal occlusion. Methods: Pre- and post-operative computed tomography (CT) examinations were performed on 12 skeletal class III anterior open bite patients who were treated with mandibular setback osteotomy. Using the V-works $4.0^{TM}$ program, 3-dimensional images of the total skull, mandible, hyoid bone, and upper airway were evaluated. Results: In the Class III open bite group, the hyoid bone were all positioned anteriorly, compared to the Normal group (p < 0.05). The angle between the hyoid plane and mandibular plane in the Class III openbite group before surgery was greater than in the Normal group (p < 0.05), and the difference increased after surgery (p < 0.01). In the Class III openbite group, the volume of the upper airway decreased after surgery (p < 0.001) and the volume of the upper airway was smaller than the Normal group before and after surgery (p < 0.001). Conclusions: The narrow upper airway space in skeletal Class III openbite patients decreased after mandibular setback osteotomy. This may affect the post-surgical stability.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.12 no.2
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• pp.69-81
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• 1990

Classification of facial asymmetry has not been yet well-organized because of their variety on etiologic factors, involved sites and clinical expressions. And surgical treatments are also variable and depend upon their causes and clinical abnormalities. This is a case report on surgical experiences of two patients who had severe facial asymmetry and could not treated pre-surgical orthodontics before surgery. One patient was belong to hemifacial microsomia and another was a very unusual complex type related to unilateral condylar hyperplasia, unilateral macrognathia and unilateral mandibular hypoplasia. The authors used a simultaneous two-jaw surgery, bone shaving and onlay-type bone graft in former case, and a simultaneous two-jaw surgery, condylectomy, bone shaving and only-type bone graft in latter case. In two cases, immediate post-operative results in function and esthetics were excellent, however, progressive resorption of onlay-type bone grafts have been noticed.

• The korean journal of orthodontics
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• v.52 no.1
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• pp.29-41
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• 2022

Objective: Condylar resorption (CR) is one of the major post-surgical complications of orthognathic surgery. This systematic review (SR) aimed to evaluate epidemiological data, risk factors, and therapeutical management of CR. Methods: Six databases were screened by two investigators until September 2020 to obtain all SRs. After reading the titles and abstracts, eligible SRs were determined and data extraction was performed. Using the latest version of A Measurement Tool to Assess Systematic Reviews, the methodological quality of the included SRs was determined. Results: Ten SRs with low or critically-low methodological quality were included in this review. Mandibular hypoplasia on the sagittal plane and hyperdivergent growth pattern on the vertical plane were the most common skeletal alterations in which CR could occur after orthognathic surgery. Post-operative condylar changes were analyzed both on two-dimensional and three-dimensional (3D) radiographic examinations. The incidence of CR was not related to the fixation method. Based on the severity of the pathological conditions, management of CR can include conservative or surgical therapy. Conclusions: Despite the limited evidence in literature, CR is considered a consequence of orthognathic surgery. However, an accurate diagnosis of CR and a better orthognathic surgical planning must include 3D radiographic examinations to improve pre- and post-surgical comparison. Well-designed studies with long-term follow-up and 3D data are needed to clarify the findings of this analysis..

• The korean journal of orthodontics
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• v.30 no.3 s.80
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• pp.367-375
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• 2000

If a mandibular prognathic patient has an extremely unnatural anteroposterior and vertical maxilla or keen esthetical perception for facial profile, orthognathic surgery must be performed along with orthodontic treatment, which alone cannot provide satisfactory results in this case. Esthetical improvement becomes an important factor in the satisfaction level of the patient's treatment result, but an attempt to objectively measure beauty holds many problems. Therefore, in the end, the patient submits the final esthetical evaluation based on his/her subjective viewpoint. Because Korean people have a tendency to prefer the facial appeareance of westerners, they favor an oval shaped face over the traditional round face. This research was conducted in response to the complaints raised by patients who claim that their face had become more round from widening of facial width after the orthognathic surgery for manidibular prognathism than before the surgery. The following results were obtained on the changes in facial appearance and patient satisfaction level by analyzing the skull P-A analysis of total of 14 patients (8 male and 6 female) who underwent orthognathic surgery primarily chief complaint for manidibular prognathism and from their responses on questionnaires. These results are to be used in the research on the pre- and post- operative changes in facial height and width from orthognatic surgery. 1. Three ($21.4\%$) of 14 patients said that their face had widened. 2. The A group showed no change in mandibular width but B group showed a 0.7mm reduction. The facial width increased by 0.45mm and 0.66mm in groups A and B, respectively, after the orthognathic surgery 3. After the surgery the facial length changed by an 0.52mm increase in upper facial height , 1.19mm reduction in lower facial height, and 0.7mm reduction in mandibular height in group A. In group B group, there was a 0.67mm reduction in upper facial height, 3.66mm reduction in lower facial height, and 5mm reduction in mandibular height. 4. In reference to facial width, the facial height showed $1.5\%$ reduction in group A and $3.6\%$ reduction in group B after the surgery. 5. In reference mandibular height-to-facial width ratio, there was a $1.3\%$ reduction in group A, and $4.4\%$ reduction in group B after the surgery. 6. In reference to the mandibular height-to-width ratio, there was a $1.3\%$ reduction in group A and $4.3\%$ reduction in group B after the surgery. 7. Although the change in the facial width due to surgery can be ignored, sufficient explanation should be Provided to the patient before surgery on the fact that the face can appear to be relatively wide because of the reduced facial length as result of the surgery.