• Maxillofacial Plastic and Reconstructive Surgery
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• v.34 no.1
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• pp.26-33
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• 2012

Purpose: The golden ratio has been used for a long time to objectify and quantify 'beauty'. Dr. Marqurardt claims that the golden ratio can be applied in the maxillofacial field as well. The purpose of this study was to evaluate the diagnostic significance of using a facial 'phi' mask for analyzing Korean faces with characteristics of Class I, II, and III malocclusion. Methods: We studied twenty five Korean celebrities' frontal facial photos (10 males, 15 females) and 90 malocclusion patients' frontal facial photos (30 patients in each malocclusion classification: Class I, Class II, and Class III). Patients who received orthodontic treatment at Samsung Medical Center were selected for this study. After superimposition of the selected facial photo and facial 'phi' mask using Adobe Photoshop CS3, the ratio of the entire facial area, mid facial area, lower facial area and horizontal and vertical lengths were measured. Results: The facial ratio in photos of Korean faces showed larger vertical and horizontal ratios than the facial 'phi' mask with golden ratio, regardless of skeletal malocclusion (entire face: 115%, lower face: 125% larger than the mask). The results of the frontal photos of Class I, II, and III malocclusion patients using facial 'phi' mask showed that the vertical length and frontal face area was more significantly influenced by the area of the lower face than the midface. This means that the lower face has larger proportions in the facial areas. Conclusion: The ratio of facial 'phi' mask is matched with the ideal facial appearance that the contemporary Korean general public is seeking. Thus, the facial 'phi' mask may be a convenient tool for esthetic analysis of Korean faces. Reducing the area of the lower face is esthetically more desirable for almost all Korean people when planning orthognathic surgery.

• Journal of the korean academy of Pediatric Dentistry
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• v.41 no.3
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• pp.225-232
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• 2014

The purpose of this study was to compare skeletal maturity index and dental developmental stages based on skeletal malocclusion. A total of 192 patients (89 male and 103 female) between 6 to 14 years old were selected for this study and underwent cephalograms, panorama radiographs, and hand-wrist radiographs. Any syndromic cases were excluded. Selected clinical parameters were dichotomised for statistical analysis. Chi-square, logistic regression analysis, and independent t-tests were used for the statistical evaluation. Canine, first molar, and second molar calcification were significantly associated with skeletal maturity in the logistic regression model (p < 0.05). In addition, patients who had higher skeletal maturity index were 11.43 times more likely to be female than those who had lower skeletal maturity index (p < 0.001). The patients with skeletal class II malocclusion displayed significantly higher dental developmental stage in canines, first premolars, first molars, and second molars than the patients with class III malocclusion (p < 0.05). The dental developmental stage of the patients was significantly associated with skeletal maturity. In addition, there was a significant difference between class II and class III malocclusion with some types of tooth calcification.

• Journal of the korean academy of Pediatric Dentistry
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• v.23 no.3
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• pp.736-745
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• 1996

The conventional treatment of skeletal Class III malocclusion has been focused on application of orthopedic force primarily to the mandible. However, In Class III malocclusion with retrograde position or underdevelopment of Maxilla, this approach is not suitable treatment. These patients need an application of orthopedic forces via face-mask to the Maxilla to stimulate its growth and to change the direction of growth. In skeletal Class III patients who were treated by Face-Mask, the following results were obtained. 1. Forward growth of Maxilla was enhanced. 2. Labioversion of upper incisors and linguoversion of lower incisors were observed. 3. Mandible was rotated to clockwise direction and remodeling of B point was observed. 4. Anterior crossbite was corrected by combining of the above results.

• Journal of Korean society of Dental Hygiene
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• v.18 no.4
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• pp.525-533
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• 2018

Objectives: This retrospective study evaluated the changes in the airway width after the orthognathic surgery associated with the skeletal Class III malocclusion. Methods: The lateral cephalograms of 30 adult patients were taken before and immediately after the operation, and after the orthodontic treatment. The angles and distances of them were measured and compared. Results: Before the surgery, the mean value of mandibular (S-B) setback was 9.66 mm, and moved by 1.56 mm anteriorly after the orthodontic treatment. The ANB increased by 5.42 degrees, since then it decreased by 0.68 degree. The hyoid bone (S-APH) moved by 5.05 mm posteriorly, but then moved by 2.26 mm anteriorly. The soft tissue width of laryngeal pharynx (apw2-ppw2) was narrowed by 1.04 mm, and decreased by additional 0.83 mm after the orthodontic treatment. Conclusions: As the mandible was moved back, the location of hyoid bone and laryngeal pharynx were moved backward.

• The korean journal of orthodontics
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• v.42 no.4
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• pp.190-200
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• 2012

Objective: The displacement of the hyoid bone (HB) is a critical biomechanical component of the swallowing function. The aim of this study was to evaluate the swallowing-induced vertical and horizontal displacements of the HB in subjects with 2 different magnitudes of skeletal Class III malocclusion, by means of real-time, balanced turbo-field-echo (B-TFE) cine-magnetic resonance imaging. Methods: The study population comprised 19 patients with mild skeletal Class III malocclusion, 16 with severe skeletal Class III malocclusion, and 20 with a skeletal Class I relationship. Before the commencement of the study, all subjects underwent cephalometric analysis to identify the nature of skeletal malformations. B-TFE images were obtained for the 4 consecutive stages of deglutition as each patient swallowed 10 mL of water, and the vertical and horizontal displacements of the HB were measured at each stage. Results: At all stages of swallowing, the vertical position of the HB in the severe Class III malocclusion group was significantly lower than those in the mild Class III and Class I malocclusion groups. Similarly, the horizontal displacement of the HB was found to be significantly associated with the severity of malocclusion, i.e., the degree of Class III malocclusion, while the amount of anterior displacement of the HB decreased with an increase in the severity of the Class III deformity. Conclusions: Our findings indicate the existence of a relationship between the magnitude of Class III malocclusion and HB displacement during swallowing.

• The Journal of Korea Assosiation for Disability and Oral Health
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• v.10 no.2
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• pp.61-67
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• 2014

The aim of this study was to analyze the clinical characteristics of patients with cognitive and behavioral impairments receiving dental treatment under general anesthesia (GA-dental treatment). From August 2007 to April 2014, information was collected from 475 patients who received GA-dental treatment at the Clinic for Persons with Disabilities, Seoul National University Dental Hospital. The demographic factors (gender, age, disability, medication, GA history, residency type, caregiver, meal type, oral hygiene maintenance, and cooperation level) and dental status (operating duration, DMFT, malocclusion, periodontal disease, tooth defect, and treatment protocol) of the patients were evaluated. DMFT and malocclusion levels were compared among the patients with ANOVA and Sheffe's post-hoc test, and chi-square test, respectively. The correlation between the demographic characteristics and dental status of the patients were analyzed with the Pearson's correction test. The mean age of the patients was 27.1 (7 - 83) years and they had intellectual disabilities (55.4%), developmental disorders (17.9%), brain disorders (16.6%), neurocognitive disorders (4.6%), or others (5.5%). The mean DMFT (DT) was 8.6 (5.2) with a significant difference among the disability types (p<0.05). The incidence of malocclusion was higher in patients with intellectual disabilities and brain disorders than in the other types (p<0.05). The operation time ($191.4{\pm}91.2min$) was correlated with decayed or endodontically-treated teeth (p<0.05). Special needs patients requiring GA-dental treatment showed unfavorable oral conditions. Dental practitioners experience time restrictions and additional costs under a GA setting. Treatment planning and decision-making can be efficiently facilitated by evaluating the clinical characteristics of the patients.

• The Journal of the Korean dental association
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• v.50 no.2
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• pp.64-71
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• 2012

Recently, the presurgical orthodontic duration tends to be shortened by virtue of the advancement of surgical and orthodontic techniques in class III orthognathic surgery cases. But the predictability of the surgical results should be secured by removing several uncertain factors in presurgical orthodontic treatment. The purpose of this study is to investigate the influence of immediate postsurgical occlusal stability on postsurgical mandibular change. The study includes 40 patients who underwent orthognathic surgery to correct skeletal class III malocclusion. The patients were divided into two groups based on the numbers of occlusal contact in surgical setup occlusion: group 1 (stable surgical occlusion, n=24) and group 2(unstable surgical occlusion, n=16). Changes of horizontal and vertical mandibular measurements during postsurgical follow up period(from 1 week postsurgery to 12month after debonding) were compared to examine the differences between two groups. The stability of surgical occlusion is one of the factors influencing postsurgical mandibular changes in class III malocclusion. The various class III malocclusion cases have specific prerequisites for the orthognathic surgery according to the skeletal patterns. The prerequisites should be obtained by minimum presurgical orthodontics to increase the predictability of the surgical results.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.6
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• pp.559-565
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• 2006

The aim of this study was to evaluate the amount and interrelationship of the soft and hard tissue changes after simultaneous maxillary clockwise rotation and mandibular setback surgery in skeletal class III malocclusion. The sample comprised of 16 adult patients who had anteroposterior skeletal discrepancy. These patients had received presurgical orthodontic treatment and surgical treatment which consisted of Le fort I Osteotomy and bilateral saggital split ramus osteotomy. The presurgical (T1) and postsurgical (T2) lateral cephalograms were evaluated. The computerized statistical analysis was carried out with SPSS/PC program. The results demonstrated a decrease in the vertical dimension in the soft and hard tissue. The nasolabial angle was increased and the mentolabial angle was decreased. The results showed also many statistically significant correlations(p<0.05). The lower lip closely followed the skeletal movement of the B- point in the horizontal plane. The double jaw rotation surgery can afford a good solution to solve the problems of class III malocclusion cases.

• Imaging Science in Dentistry
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• v.50 no.1
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• pp.9-14
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• 2020

Purpose: The purpose of this study was to evaluate vertical bone loss and alveolar bone thickness in the maxillary and mandibular incisors of patients with skeletal class III malocclusion. This study also aimed to evaluate the periodontal condition of class III malocclusion patients who had not undergone orthodontic treatment. Materials and Methods: The sample included cone-beam computed tomography scans of 24 Korean subjects (3 male and 21 female). Alveolar bone thickness (ABT), alveolar bone area (ABA), alveolar bone loss (ABL), and fenestration of the maxillary and mandibular incisors were measured using 3-dimensional imaging software. Results: All incisors displayed an ABT of less than 1.0 mm from the labial surface to root level 7 (70% of the root length). A statistically significant difference was observed between the mandibular labial and lingual ABAs and between the maxillary labial and mandibular labial ABAs. The lingual ABA of the mandibular lateral incisors was larger than that of the mandibular central incisors. ABL was severe on the labial surface. A statistically significant difference was observed between the maxillary and mandibular labial ABL values(21.8% and 34.4%, respectively). Mandibular lingual ABL (27.6%) was significantly more severe than maxillary lingual ABL (18.3%) (P<0.05). Eighty-two fenestrations were found on the labial surfaces of the incisors, while only 2 fenestrations were observed on the lingual surfaces. Fenestrations were most commonly observed at root level 6. Conclusion: Careful evaluation is needed before orthodontic treatment to avoid iatrogenic damage of periodontal support when treating patients with class III malocclusion.

• The korean journal of orthodontics
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• v.48 no.3
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• pp.143-152
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• 2018

Objective: This study examined cone-beam computed tomography (CBCT)-derived multiplanar-reconstructed (MPR) cross-sections to clarify the salient characteristics of patients with skeletal class III malocclusion with midface deficiency (MD). Methods: The horizontal and sagittal plane intersection points were identified for middle-third facial analysis in 40 patients in the MD or normal (N) groups. MPR images acquired parallel to each horizontal plane were used for length and angular measurements. Results: A comparison of the MD and N groups revealed significant differences in the zygoma prominence among female patients. The convex zygomatic area in the N group was larger than that in the MD group, and the inferior part of the midface in the N group was smaller than that in the MD group for both male and female patients. A significant difference was observed in the concave middle maxillary area among male patients. Conclusions: This study was conducted to demonstrate the difference between MD and normal face through MPR images derived from CBCT. Male patients in the MD group had a more flattened face than did those in the N group. Female patients in the MD group showed a concave-shaped lower section of the zygoma, which tended to have more severe MD. These findings indicate that orthognathic surgery to improve skeletal discrepancy requires different approaches in male and female patients.