• 대한치과의사협회지
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• 제19권7호통권146호
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• pp.615-623
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• 1981

The purpose of this study was observing the annual growth increment in Cephalogram. The Cephalograms of 28 boys & 22 girls were analized by method of Downs & Steiner, range from 7 to 9 years in Korean children. The results were as follows. 1. The change of gonial angle in both male and female is not presented in this age. 2. The most significant linear change of both male and female is the facial depth (Na-Go) and that of both male and female is the interincisal angle in this age. 3. The increment of the mandibular body length (Go-Me) and the anterior facial height (Na-Me) is presented in this age. 4. The change of SNA and SNB in both male and female is negligible is negligible in this age.

• 치과방사선
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• 제17권1호
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• pp.209-222
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• 1987

The author invested the gonial angle, the angle of mandibular and mental canal to the lower border of the mandible, and a relationship of the position of the mandibular canal to the root apex of the posterior teeth and the cortical plate of the lower of the mandible. The materials consisted of 458 pantomograms in male and female aged 11-40 and divided into 5 groups at 5 year intervals and subdivided into 3 groups by gonial angle. The results were as follows; 1. The gonial angle decreased with age, but slight increase occurred over 26-30 years. 2. The average angle of the mandibular canal to the lower border of the mandible was 151.6° and did not correlate with age. 3. The average angle of the mental canal to the lower border of the mandible was 36.9° and didn't correlate with age. 4. The angles of mandibular and mental canal to the lower border of the mandible correlated with gonial angle. 5. The distance from the root apex of the posterior teeth to the upper wall of the mandibular canal was most short at the region of the distal root of the mandibular second molar and increased with age at the region of the mandibular second molar. 6. The distance from the lower wall of the mandibular canal to the cortical plate of the lower border of the mandible was most short at the region of the mesial root of the mandibular first molar and didn't correlate with age.

• Journal of Korean Dental Science
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• 제7권1호
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• pp.16-24
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• 2014

Purpose: This study was planned to clarify a negative view of chewing gum due to the concern that continuous gum chewing might cause a change in the gonial angle and make the lower facial appearance look square. Materials and Methods: We had 25 adults (13 males and 12 females, with an average of 27.3 years) chew 6 g of gum (spearmint) evenly with both right and left posterior teeth for one hour per day for three months. We then measured their gonial angle, the inclination of occlusal plane, facial height, bone marrow density, and masticatory force before chewing, 1, 2, and 3 month after chewing to verify its significance statistically. Result: The results showed that the gonial angle increased from $122.7^{\circ}$ to $123.3^{\circ}$ (P>0.05), and thus the jaws became slightly slimmer. There was no change in the occlusal plane inclination and facial height. Meanwhile bone marrow density in the mandibular angle and ascending ramus increased from $0.285g/cm^2$ to $0.290g/cm^2$ (P<0.05), and masticatory force also increased by 0.5 kg on the right side and 0.8 kg on the left side (P<0.05). Conclusion: Continuous chewing of gum gives an appropriate exercise effect to the stomatognathic system. As chewing gum has effect on increase bone marrow density without changing the mandibular angle and facial appearance the claim that jaw bone changes to a square jaw through chewing gum is regarded to be groundless.

• 대한치과기공학회지
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• 제27권1호
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• pp.27-39
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• 2005

This study is to show the qualitative analytic methods of facial asymmetry with three-dimensional morphometry and find out asymmetry change resulted from enlarging three local regions. Steel balls (1.2mm in diameter) were attached in twenty seven landmarks of a symmetrical artificial human skull. This artificial human skull was used as experimental materials. Twelve different asymmetrical artificial human skulls were formed by gradually enlarging the mandibular body length, gonial angle, and ramus height of the left hemiface. From the three-dimensional morphometry of each skull type, nine local area measurements and three total sum area measurements(representing the mandibular area, maxillary area, and lower facial area) were acquired and made into the surface area asymmetry degree. Menton deviation itself was used as the surface area asymmetry degree while right-left percentages were used in the other measurements. These surface area asymmetry degrees were compared with each other to find out asymmetry change according to the degree of actual facial asymmetry. Through the statistical analysis, following results were obtained. The results were as follows: 1. Left maxillary area of artificial human skull was 7.13$\pm$0.26% larger while mandibular area was 4.14$\pm$0.12% smaller than each those of right hemiface. After all, left lower facial area was 1.44$\pm$0.07% larger than those of right hemiface.(n=7). 2. Among the reduce rates of surface area asymmetry degree resulted from enlarging three local regions, ramus height was similar to mandibular body length while it was bigger than those of gonial angle. 3. Among the increase rates of menton deviation resulted from enlarging the local regions, ramus height was the biggest, mandibular body length was the second and gonial angle was the smallest. These results suggest that three-dimensional morphometry can be used to qualitatively analyse facial asymmetry and the asymmetry degree is more influenced by enlarging the ramus height, mandibular body length than those of gonial angle.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제33권2호
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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.

• 대한치과의사협회지
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• 제21권12호통권175호
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• pp.985-990
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• 1983

320 cephalometric roentgenograms of 25 boys and 15 girls which was longitudinally taken from the age 6.5 to 13.5 have been analyzed to access the angular growth changes of the mandible. The statistical analysis of the results allowed the following conclusions. 1. Gonial angle was reduced with ageing. 2. Chin angle was reduced with ageing. 3. Occlusal plane to mandibular plane angle was relatively stable. 4. Lower incisor to occlusal plane angle was reduced and showed the greatest variability.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제40권3호
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• pp.123-129
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• 2014

Objectives: The aim of this study was to verify the concordance of the measurement values when the same cephalometric analysis method was used for two-dimensional (2D) cephalometric radiography and three-dimensional computed tomography (3D CT), and to identify which 3D Frankfort horizontal (FH) plane was the most concordant with FH plane used for cephalometric radiography. Materials and Methods: Reference horizontal plane was FH plane. Palatal angle and occlusal plane angle was evaluated with FH plane. Gonial angle (GA), palatal angle, upper occlusal plane angle (UOPA), mandibular plane angle (MPA), U1 to occlusal plane angle, U1 to FH plane angle, SNA and SNB were obtained on 2D cephalmetries and reconstructed 3D CT. The values measured eight angles in 2D lateral cephalometry and reconstructed 3D CT were evaluated by intraclass correlation coefficiency (ICC). It also was evaluated to identify 3D FH plane with high degree of concordance to 2D one by studying which one in four FH planes shows the highest degree of concordance with 2D FH plane. Results: ICCs of MPA (0.752), UOPA (0.745), SNA (0.798) and SNB (0.869) were high. On the other hand, ICCs of gonial angle (0.583), palatal angle (0.287), U1 to occlusal plane (0.404), U1 to FH plane (0.617) were low respectively. Additionally GA and MPA acquired from 2D were bigger than those on 3D in all 20 patients included in this study. Concordance between one UOPA from 2D and four UOPAs from 3D CT were evaluated by ICC values. Results showed no significant difference among four FH planes defined on 3D CT. Conclusion: FH plane that can be set on 3D CT does not have difference in concordance from FH plane on lateral cephalometry. However, it is desirable to define FH plane on 3D CT with two orbitales and one porion considering the reproduction of orbitale itself.

• 대한치과교정학회지
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• 제25권6호
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• pp.665-674
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• 1995

The purpose of this study is to investigate the cephalometric characteristics of the open-bite patients with DJD of TMJ. The DJD open-bite cases were compared with normal samples and Class II open-bite cases with normal TMJ respectively. Twenty three open-bite patients with bilateral DJD of TMJ($13.9\~35.3$ yens old, Group I) were selected from the Department of Orthodontics, SNUDH. Group ll consisted of thirteen Class II open-bite cases($13.2\~27.4$ years old) with no TMD signs/symtoms and good condylar shapes. Group III samples were the forty eight healthy dental students who have Class I molar relationships with no history of orthodontic treatment, good facial balance and no TMD symptoms($20.0\~26.8$ years old). First, sixty measurements in the lateral cephalometric radiographs and analysis of variance(P<0.05, Scheffe) were used to compare these three groups. The seven measurements showed significant difference(p<0.05) between Group I and Group II. After analysis of variance, six of them were used for the discriminant analysis(Wilks' stepwise analysis) and the discrminant function for Group I/Group II was obtained. The results and conclusions were as follows : In most of the measurments, Group I and Group II showed the same skeletal and dental characteristics. But seven of the sixty measurements(FH-PP angle, SNB, FH-ArGo angle, articulare angle, genial angle, upper gonial angle and Ar-Go length) were significantly different(p<0.05) between Group I and Group II. These differences may be explained by the fact that in DJD cases the mandible rotated backward due to the shortening of the ramus following the degenerative destruction of condylar head and its surrounding structures. The resulting discriminant function was : $D={-0.120X}_1+{0.066X}_2+{0.144X}_3-{0.058X}_4+2000,\;where\;X_1=ArGo\;length(mm),\;X_2=SArGo\;angle(degree),\;X_3=FH-PP\;angle(degree),\;X_4=Gonial\;angle(degree)$. Mean of the group centroids was -0.555 and percent of the 'grouped' cases correctly classified was $88.89\%$.

• 대한치과의사협회지
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• 제18권3호통권132호
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• pp.197-200
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• 1980

This study was undertaken to investigate the form and position of the mandible of upper prognathism in relation to craniofacial complex. The subjects consist of 20 males and 39 females with Class II, Division 1 malocclusion and measurements were achieved on lateral cephalograms. The results were a follows. 1. Infradentale was situated anteriorly to orbital plane, but point B, pogonion and menton were situated posteriorly. 2. Development of chin point area of female was poor than that of male. 3. In case of facial angle was large, ramus angle tend to be small, but gonial angle had tendency to be large.

• 대한치과교정학회지
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• 제48권1호
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• pp.11-22
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• 2018

Objective: The aim of this study was to determine cephalometric factors that help predict favorable soft-tissue profile outcomes following treatment with the Class II Twin-block appliance. Methods: Pre- and post-treatment lateral cephalograms of 45 patients treated with the Class II Twin-block appliance were retrospectively analyzed. Profile silhouettes were drawn from the cephalograms and evaluated by three orthodontists in order to determine the extent of improvement. Samples were divided into a favorable group (upper 30% of visual analogue scale [VAS] scores, n = 14) and an unfavorable group (lower 30% of VAS scores, n = 14). Skeletal and soft-tissue measurements were performed on the cephalograms and an intergroup comparison was conducted. Results: An independent t-test revealed that the following pre-treatment values were lower in the favorable group compared to the unfavorable group: lower incisor to mandibular plane angle, lower incisor to pogonion distance, point A-nasion-point B angle, sella-nasion line (SN) to maxillary plane angle, SN to mandibular plane angle, gonial angle, and symphysis inclination. The favorable group had a larger incisor inclination to occlusal plane. Moreover, the favorable group showed larger post-treatment changes in gonial angle, B point projection, and pogonion projection than did the unfavorable group. Conclusions: Class II malocclusion patients with a low divergent skeletal pattern and reduced lower incisor protrusions are likely to show more improvement in soft-tissue profile outcomes following Class II Twin-block treatment.