• Maxillofacial Plastic and Reconstructive Surgery
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• 제34권3호
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• pp.180-185
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• 2012

Purpose: An accurate preoperative analysis of the patient is essential in orthognathic surgery in order to acquire superior results. In profile, the location of the chin's position may change according to the neck's inclination. This may ultimately affect the amount of surgical movement. During acquisition of cephalometric radiographs, or in supine position, there is a discrepancy in the neck's inclination. This means that there are also various discrepancies between the actual profile and the various preoperative profile images. In the clinical situation, the decision in performing genioplasty usually lies in the analysis of the patient's profile on the operating table at the final stages of orthognathic surgery. This study aims to analyze the different preoperative profile images and to compare their discrepancies. Methods: Fifty eight patients undergoing orthognathic surgery were chosen. These patients were divided into three groups according to angle's classification of malocclusion, as class I, II or III. The right profile of these patients in centric occlusion was taken in natural head position (NHP). This was set as the 'actual profile image.' Another right profile image was taken on the operating table after insertion of the nasotracheal intubation and with muscle relaxants in effect. This was also taken in centric occlusion. The angle (denoted 'A') between the soft tissue glabella-pognion and the true vertical plane was found in the above-mentioned profile images and in the cephalometric radiographs. The differences of these values were analyzed. Results: There were differences in Angle 'A' in all of the preoperative images. These values were however, not statistically significant. Conclusion: In order to gain an esthetic profile during orthognathic surgery, the NHP is shown to be the most reliable position. Images reproducing such head positions should be used in the treatment planning process.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제33권3호
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• pp.218-224
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• 2011

Purpose: The purpose of this study is to evaluate the post-operative skeletal stability after surgical correction of patients with mandibular prognathism by bilateral sagittal split ramus osteotomy (BSSRO) and to evaluate the horizontal relapse tendency after the surgery. Methods: Twenty-six patients with Class III dental and skeletal malocclusion were selected for this retrospective study. Fifteen of them underwent BSSRO for mandibular setback and eleven of them underwent two-jaw surgery (Lefort I and BSSRO). In each patient, lateral cephalometric radiographs were taken pre-operatively, post-operatively within 1 week, and post-operatively after eight months. After tracing of the cephalometric radiographs, various parameters were measured. The analyses were done by linear measurement to evaluate the change in position of hard tissue B point, pogonion and mandibular plan angle by examination on lateral cephalograms. Results: The horizontal relapse rate was 27.1% at B point and 31.6% at pogonion in patients who underwent BSSRO. The horizontal relapse rate of the group where the amount of correction exceeded 10 mm was 25.69% at B point. Conclusion: There were no statistical differences on the magnitude of setback and direction of rotation of the mandible in mandibular stability. There were also no statistical differences between single mandibular surgery and two-jaw surgery for mandibular stability.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제38권
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• pp.12.1-12.6
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• 2016

Background: Temporomandibular joint (TMJ) ankylosis can be accompanied by various degrees of functional and esthetic problems. Adequate mouth opening, occlusal stability, and harmonious facial form are the main goals of treatment for ankylosis. Distraction osteogenesis has proven to be an excellent treatment for lengthening the ramus-condyle unit. However, various timings for distraction have been suggested, and there is no consensus on selection criteria for performing the procedure in stages or simultaneously with other treatments. Case presentation: In this case report, concomitant intraoral distraction and gap arthroplasty was planned to treat TMJ ankylosis and associated facial asymmetry. After gap arthroplasty and 23 mm of distraction, the ramus-condyle segment was successfully lengthened and mouth opening range was significantly increased. The resultant interocclusal space was stably maintained with an occlusal splint for 4 months after distraction. Finally, good occlusion was achieved after prosthetic treatment. The remaining mandibular asymmetry was corrected with osseous contouring and augmentation surgery. The mouth-opening range was maintained at 35 mm 24 months after treatment. Conclusion: Gap arthroplasty with intraoral distraction as a one-stage treatment and subsequent contouring surgery can be applied to correct ankylosis with moderate malocclusion and facial asymmetry.

• 대한치과교정학회지
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• 제13권2호
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• pp.177-183
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• 1983

The soft tissue covering of the face plays an important role in facial esthetics, speech and other physiologic functions. Thus, it is recognised by all clinical orthodontists that success of orthodontic treatment is closely related to the changes in soft tissues of the face. The purpose of this study was to evaluate the changes of bony and soft tissues in prepost treatment of Angle's Class III malocclusion. The sample consisted of 18 males and 37 females, pretreatment age of 9 years to 11 years. For this study 11 landmarks were plotted, 14 linear length, 4 soft tissue thickness and 2 angles were measured. The obtained results were as follows; 1. In the linear measurements of bony and soft tissue changes, A, Is, Ss, Ls and Li were located more anteriorly in both sexes. However Si and B showed more remarkable anterior movement in female. 2. In the comparison of the changes of the soft tissue thickness, Ss and Li in male subjects and Ss in female subjects increased. 3. In the degree of correlation between changes in the soft tissue profile and changes in the skeletal profile, Is: Ls, Il: Li and B: Si in both sexes had significant correlations. However A:Ss had remarkable significant correlation in female. 4. There were significant correlations between change in ${\angle}A$ and change in ${\angle}B$ in all sexes. 5. There were little correlation between changes in distance difference of Is and Ii and Change in distance difference of Ls and Li in all sexes.

• 대한두개안면성형외과학회지
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• 제14권2호
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• pp.119-123
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• 2013

Except for special situations, it is generally agreed that best results in the treatment of facial fractures is expected if reduction is done within the first 2 or 3 weeks after injury. We reduced facial bone fractures at 4 to 7 weeks after trauma. A 44-year-old female patient underwent open reduction for her right zygomaticomaxillary complex fracture at 7 weeks after injury. A 59-year-old female patient underwent surgery for the right mandible body and left parasymphysis fractures at 4 weeks after injury. Using traditional approaches, granulation tissue and callus were removed from the fracture sites, and malunited fracture lines were separated by a small osteotome. We reduced the displaced fractured zygoma and mandible to their normal anatomical positions and fixed them using titanium plates. No complications such as asymmetry, malunion, malocclusion, or trismus were seen. Unfavorable asymmetric facial contours were corrected, and we obtained good occlusion with favorable bony alignment. The functional and aesthetic outcomes were satisfactory. Through removal the callus and limited osteotomy, a successful approach to the previously fractured line was possible, and an exact correction with symmetry was obtained. This method can be a good option for obtaining good mobility and clinical results in treating delayed facial bone fractures.

• 대한치과교정학회지
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• 제46권2호
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• pp.96-103
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• 2016

Objective: To compare the transverse dental changes induced by the palatally applied Frog appliance and buccally applied Karad's integrated distalizing system (KIDS). Methods: We evaluated the pre- and post distalization orthodontic models of 39 patients, including 19 treated using the Frog appliance, which is palatally positioned (Frog group), and 20 treated using KIDS, which is buccally positioned (KIDS group). Changes in intermolar and interpremolar distances and the amount of maxillary premolar and molar rotation were evaluated on model photocopies. Wilcoxon and Mann-Whitney U tests were used for statistical evaluations. A p-value of < 0.05 was considered statistically significant. Results: Significant distopalatal rotation of premolars and distobuccal rotation of molars were observed in Frog group (p < 0.05), while significant distopalatal rotation of molars (p < 0.05), with no significant changes in premolars, was observed in KIDS group. The amount of second premolar and first molar rotation was significantly different between the two groups (p < 0.05 and p < 0.001, respectively). Furthermore, expansion in the region of the first molars and second premolars was significantly greater in KIDS group than in Frog group (p < 0.001 for both). Conclusions: Our results suggest that the type and amount of first molar rotation and expansion vary with the design of the distalization appliance used.

• 대한치과교정학회지
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• 제47권1호
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• pp.39-49
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• 2017

Objective: This retrospective, cross-sectional study aimed to establish reference data for normal crown and root lengths and the root-crown ratios (R/C ratios) for the mature maxillary and mandibular incisors in a Korean population by using cone-beam computed tomography (CBCT). Methods: We included 672 Korean patients (141 men and 531 women; mean age, $27.2{\pm}7.7years$) who underwent CBCT examinations during various dental treatments. Crown and root lengths and the R/C ratios of the maxillary and mandibular incisors were measured using CBCT data, which were analyzed to detect significant differences between demographic factors as well as sagittal and vertical skeletal or occlusal relationships. Results: Teeth of the same type in each half-arch were symmetrical. The mean R/C ratios varied from 1.1 to 1.2 for the maxillary incisors and from 1.3 to 1.4 for the mandibular incisors. Crown and root lengths were greater in men than in women, regardless of tooth type. Root lengths and R/C ratios for the mandibular incisors were significantly greater in patients with skeletal Class II malocclusion or an excessive overjet than in the other patients. The R/C ratios for the mandibular incisors were lower in patients with an open bite than in those with a normal or deep bite. Moreover, the R/C ratios for the mandibular incisors increased with age. Conclusions: The data obtained in our study can serve as reference values for crown and root lengths and the R/C ratios for the maxillary and mandibular incisors in the Korean population.

• Journal of Oral Medicine and Pain
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• 제25권1호
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• pp.117-128
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• 2000

The present study explored the influence of temporomandibular disorders(TMD) with anterior open bite on swallowing. Fifteen subjects with anterior open bite(group A), 9 subjects with anterior open bite and TMD(group B), and 24 subjects without malocclusion or TMD symptoms (group C) were included. BioPAK system(Bioresearch Inc., Milwaukee, WI, USA) was used to record the muscle activities of anterior temporal, masseter, sternocleidomastoid(SCM) and anterior digastric muscles during maximum clenching and swallowing. Positional change of the mandible during swallowing was also recorded using the same system. The obtained results were as follows: 1. Group A, B, and C did not show significant differences each other in the muscle activity of resting position in most of head and neck muscles. 2. Group B showed significantly lower muscle activity in maximum clenching than group C in anterior temporal(p<0.01), masseter(p<0.05), SCM(p<0.05) and digastric muscles(p<0.05). 3. Group A showed significantly lower muscle activity during swallowing than group C in anterior temporal and masseter muscles(p<0.01). Group B showed significantly lower muscle activity during swallowing than group C in anterior temporal(p<0.01), masseter(p<0.01), and SCM muscles(p<0.05). 4. Group A and B showed increased positional change of the mandible during swallowing measured from vertical, anteroposterior and lateral aspects, and prolonged swallowing(p<0.05). 5. After given instructions for normal swallowing pattern, group A and B showed increased muscle activity during swallowing in anterior temporal, masseter and SCM muscles(p<0.01). Positional change of the mandible and time elapsed for swallowing also decreased after the instruction(p<0.01). 6. Occlusal splint did not change the muscle activity during swallowing. However, vertical change(p<0.01) and swallowing time(p<0.05) were decreased with splint.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제40권2호
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• pp.76-82
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• 2014

Objectives: The aim of this study is to report the results of extracorporeal fixation in patients with mandibular condylar fractures and compare them with the clinical results of conservative treatment. Materials and Methods: The medical records of 92 patients (73 male [M] : 19 female [F], age 13-69 years, mean 33.1 years) treated for condylar fractures at the Department of Oral and Maxillofacial Surgery in Sun Dental Hospital (Daejeon, Korea) from 2007 to 2012 were reviewed. Patients were divided into three groups: group A (23 patients; M : F=18 : 5, age 21-69 years, mean 32.6 years), treated with extracorporeal fixation; group B (30 patients; M : F=24 : 6, age 16-57 years, mean 21.1 years), treated by conventional open reduction; and group C (39 patients; M : F=31 : 8, age 16-63 years, mean 34.4 years), treated with the conservative method ('closed' reduction). Clinical and radiographic findings were evaluated and analyzed statistically. Results: Occurrence of postoperative condylar resorption correlated with certain locations and types of fracture. In this study, patients in group A (treated with extracorporeal fixation) did not demonstrate significant postoperative complications such as malocclusion, mandibular hypomobility, temporomandibular disorder, or complete resorption of condyle fragments. Conclusion: In superiorly located mandibular condyle fractures, exact reconstruction of condylar structure with the conventional open reduction technique can be difficult due to the limited surgical and visual fields. In such cases, extracorporeal fixation of the condyle using vertical ramus osteotomy may be a better choice of treatment because it results in anatomically accurate reconstruction and low risk of complications.

• 대한치과보철학회지
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• 제26권1호
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• pp.63-84
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• 1988

Recently the instantaneous centre concept has been used to understand the biomechanics by which a tissue derangement causes a mechanical derangement in temporomandibular joint. In this study, four male subjects without temporomandibular joint disorder and malocclusion were selected for the determination of the instantaneous centre of rotation (I.C.R) in the mandibular movement. The habitual opening and closing paths were recorded on the sagittal plate by two spring pencils attached on the lower anterior teeth which was designed for this study, and the I.C.R. was calculated by the computer program of Rouleaux's method. Also the computer graphic opening and closing movements of mandible were obtained according to the determined I.C.R. The results obtained from this study were as follows. 1. The instantaneous centres of rotation were not positioned within the condyle in the mandibular opening and closing movement. 2. There was some similarity between the anatomical curvature of the articular emience and the movement pattern of condyle. 3. The opening path and the closing path of the most superior pl)int of the condyle stowed a slight difference. 4. At the early stage of the habitual opening movement, the condyle was moved downward. 5. The opening and closing mandibular movements were simulated by the instantaneous centre of rotation which was determined by the computer program of Rouleaux's method.