A study on horizontal reference planes in lateral cephalogram in Korean children / 대한치과교정학회지

Various types of horizontal reference planes are used for diagnosis, treatment planning and evaluation of treatment results. But these reference planes lack accuracy and repro- ducibility, and are mainly for Caucasian. Unlike the adult patients who have completed growth, the horizontal reference planes for growing children may change continuously during growth, Therefore this must be considered in selecting the horizontal reference plane. The purpose of this study was to investigate the angle formed by the Sella-Nasion(SN) plane and Frankfort-Horizontal(FH) plane and evaluate the angle formed by FH plane and other horizontal reference planes in relation to different skeletal maturity and malocclusion types. 540 subjects with no orthodontic treatment history were chosen, and hand wrist X-rays and lateral cephalometric X-rays were taken, According to SMA(Skeletal maturity Assessment)of hand -wrist X-rays, the subjects were classified into 3 skeletal maturity groups ; SMI 1-2 for group A, SMI 5-7 for group B and SMI 8-11 for group C. A second classification was made according to cephalometric analysis of lateral cephalograms. The subjects were classified into 3 malocclusion group ; Skeletal Class I,II and III malocclusion group. 10 measurements were evaluated. The results were as follow. 1. The angle formed by the SN plane and FH plane showed no difference among skeletal maturity groups, malocclusion groups, and between sexes. 2. The angles formed by the SN plane and FH plane were 8.27degrees+/-2.31degrees for males and 8.59degrees+/-2.24degrees for females. The average value for females and males was 8.42degrees+/-2.28degrees. 3. The angle formed by the FH plane and palatal plane was almost constant showing no difference among skeletal maturity groups, malocclusion groups, and between sexes( 1.0 9degrees+/- 3.21degrees).

A study on horizontal reference planes in lateral cephalogram in Korean adults / 대한치과교정학회지

The purpose of this study was to investigate the angle formed by the Sella-Nasion(SN) plane and Frankort-Horizontal(FH) plane and evaluate the correlation and difference of the FH plane to other horizontal reference planes. Through this study we hope to present a basis for selecting a horizontal reference plane which can be implemented in cephalometric studies and in surgical orthodontic treatment planning. 600 subjects were chosen following a clinical examination and lateral cephlometric X-rays were taken. According to cephalometric analysis the subjects were classified into 3 groups; Skeletal Class I malocclusion or normal occlusion group(male 50, female 50), Skeletal Class II malocclusion group(male 50, female 65) and Skeletal Class III malocclusion group(male 50, female 50). The results were as follows. 1. The angle formed by the SN plane and FH plane showed no difference among the malocclusion groups, but there was a significant sex difference. For males the angle measured was 7.47degrees+/-2.40degrees whereas for females it was 8.93degrees+/-2.72degrees. 2. The angle formed by the SN plane or FH plane and Mandibular plane was higher in females for all malocclusion groups. This angle in the Skeletal Class I malocclusion group was 1 awer than in the other two groups. 3. There was no difference among the sexes or malocclusion groups con ,idering the angle formed by the FH plane and Palatal plane. 4. The gonial angle in the Skeletal Class III malocclusion group was higher than in the Skeletal Class I and Class II malocclusion groups- in both sexes.