• Title/Summary/Keyword: Mandibular height-to-facial width ratio

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A study of post-operative changes in facial height and width of mandibular prognathic patients (하악전돌증 환자의 수술후 안모길이 및 폭경의 변화에 관한 연구)

  • Kim, Eun-Joo;Moon, Cheol-Hyun
    • 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.

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Posteroanterior cephalometric characteristics in skeletal Class III malocclusion (골격성 III급 부정교합자의 정모 두부규격방사선 계측학적 특징)

  • Chong, Song-Woo;Hong, Sung-Gyu;Kim, Jong-Ghee
    • The korean journal of orthodontics
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    • v.29 no.3 s.74
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    • pp.317-325
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    • 1999
  • In proper diagnosis of skeletal Class III malocclusion, it was important to know the pattern of three dimensional skeletal & facial disharmony. The purpose of this study was to obtain P-A cephalometric characteristics in skeletal Class III malocclusion comparing with normal occlusion. The samples were consisted of 120 subjects, divided into four groups : Male normal occlusion, Female normal occlusion, Male skeletal Class III malocclusion, Female skeletal Class III malocclusion. Posteroanterior and lateral cephalogram were taken from the subjects with a x-ray apparatus (ASHAI CX90SP, Japan) and traced on acetate paper with routine manner. The transverse and vertical values from posteroanterior cephalometry, the sagittal values from lateral cephalometry and their ratio were obtained. The results were as follows: 1. The anteroposterior discrepancy in skeletal Class III group was not due to short maxillary length(Cd-A), but to longer mandibular length(Cd-Gn) than normal occlusion group. 2. The faces of skeletal Class III group were longer than normal occlusion group. It was not due to increase of upper face height(Cg-ANS) but to increase of the lower face height(ANS-Me) especially mandibular height(Cd-Me). 3. There was no difference in the facial width values between normal occlusion group and skeletal Class III group, except upper molar width(U6-U6), lower molar width(L6-L6) and mandibular width(Ag-Ag) of female skeletal Class III group which were larger than normal occlusion group. 4. The increase of mandibular length of skeletal Class III group was reflected in the increase of lower facial height but did not have an effect on the mandibular width.

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A STUDY ON THE MORPHOLOGIC DIFFERENCES BETWEEN LONG-FACE ADULTS AND NORMAL-FACE ADULTS ON THE LATERAL AND P-A CEPHALOGRAMS (Long face를 갖는 성인과 normal face를 갖는 성인의 측모와 정모 두부방사선 사진상에서 안모유형의 차이에 관한 연구)

  • Kim, Hyun-Do;Sohn, Byung Wha
    • The korean journal of orthodontics
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    • v.20 no.2
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    • pp.293-304
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    • 1990
  • The purpose of this study was to describe the morphologic differences between long-face adults and normal-face adults on the lateral and P-A cephalograms. Long-face and normal-face subifects were selected clinically, and then each of them was taken the lateral cephalogram. According to SN-MP angle and ATFH on the lateral cephalogram, long-face group and normal-face group were classified. 2 long-face adults and 18 normal-face adults were collected, and each of them was taken the P-A cephalogram. The results were as follows: 1. The morphologic differences between long-face adults and normal-face adults were closely related to mandibular morphology. 2. Long-face adults, compared with normal-face adults, demonstrated significant increase in ALFH, and significant decrease in ramus height. 3. Long-face adults, compared with normal-face adults, demonstrated significant increase in AUDH and, ALDH, especially in ALDH. 4. On the P-A cephalogram, no measures of transverse dimension demonstrated significant differences between two groups. 5. On the P-A cephalogram, facial height/facial width ratio was significantly larger than normal in the long-face adults, and in the normal-face adults, facial height/facial width ratio was approximately 90%. 6. In the correlation analysis of SN-MP angle and ATFH with all the other variables, the correlation coefficients of SN-MP angle and PTFH/ATFH that of ATFH and ALFH on the lateral cephalogram demonstrated the highest value, and on the P-A cephalogram, SN-MP angle and Cg-GA-Me (Lt.), ATFH and lower facial height demonstrated the highest value of correlation coefficients.

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A Posteroanterior Cephalometric Study on Craniofacial Proportions of Koreans with Normal Occlusion (한국인 정상 교합자의 정모 두부 방사선 사진을 이용한 안모비율에 관한 연구)

  • Baik, Hyoung-Seon;Yu, Hyung Seog;Lee, Kie-Joo
    • The korean journal of orthodontics
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    • v.27 no.4 s.63
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    • pp.643-659
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    • 1997
  • For the total treatment of skeletal malocclusions, 3-dimensional evaluation and diagnosis are essential. Although anteroposterior discrepancies can be evaluated through various methods, the satisfactory methods for evaluations of facial asymmetry and transverse discrepancies are yet to be found. The adequate diagnosis and treatment of transverse discrepancies may be more important in the maintenance of functional occlusion as well as for the stability of results obtained from orthognathic surgery than the anteroposterior or vertical discrepancies. Since the soft tissue effects from the transverse discrepancies may not be pronounced, especially when combined with anteroposterior or vertical discrepancies which have prominent characteristics, the differentiation of their effects may be difficult from visual inspection alone. Therefore it is essential that the normal facial proportions would be established from the posteroanterior cephalometry as a reference for the accurate diagnosis and treatment. The present study evaluates 76 subjects from Yonsei University freshmen with normal facial symmetry and occlusion. Posteroanterior cephalograms were taken from the subjects and the normal values and facial proportions are obtained. The results are as follows. 1. The transverse and vortical values from posteroanterior cephalometry and their ratio, with means and standard deviations are calculated. 2. The ratio of vertical values to transverse values is 0.837 (male 0.836, female 0.841). 3. The Proportion of maxillary and mandibular widths is 0.747 (male 0.745, female 0.752), with statistically significant correlation. 4. Various degree of significant correlations are observed in the following craniofacial widths; (Cranial width, Bizygomaticofrontal suture width, Facial width, Maxillary width, Upper & Lower Intermolar width, Mandibular width). 5. Although the facial height as well as other line measurements increase as the facial widths increase, angle measurement ($Bj\ddot{o}rk$ Sum, Mandibular Plane Angle, Gonial Angle), decreases and posterior to anterior facial height ratio increases, therefore indicating the tendency for a brachycephalic facial type. These results may be used as references for the treatment planning in orthognathic and orthodontic treatments for the dentofacial deformity patients.

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