| ODI and APDI are suggested by Dr. Kim for orthodontic diagnosis, which are the indexes for the cephalometric analysis to evaluate vertical and sagittal cranio-maxillar pattern respectively. They are of important value on clinical application.As the indexes for vertical and sagittal cranio-maxillary pattern evaluation, ODI and APDI have been accepted widely. In the orthodontic cephalometry, the application of any measurement is based on the establishment of the normal value of individuals with normal occlusion. It is necessary to compare results of measurement with the normal value to decide whether the results are normal or abnormal and how severe the abnormality is. Based on the decision, the diagnosis would be suggested. It is the way for ODI and APDI to be used. The normal range of ODI and APDI suggested by Kim was derived from Caucasian adolescent individuals with normal occlusion. Just as Kim's view, for the normal range of ODI and APDI, there are differences between different regions, different races and different ages, which has been approved by some studies. Therefore, it is necessary to establish individual normal range of the two indexes for different region and race. And it is the purposes for the normal range to be established for the individuals with normal occlusion in Xi'an in this study.In this study, the distributions of ODI in malocclusion with deep bite, normal overbite and open bite were investigated, as well as the distributions of APDI in class I,ⅡandⅢmalocclusion were investigated. They are the required references for the clinical applications of the two indexes. Meanwhile, the speciality of the indexes in corresponding malocclusion was investigated because of the clinical applications.Research contents:1. The values of ODI and APDI were measured in 120 individuals with normal occlusion in XI'an on the lateral cephalometric radiograph. Then, the normal range of the two indexes in the area was obtained.2. 180 lateral cephalometric radiographs from the individuals with corresponding malocclusion were chosen randomly. They were divided into 3 groups as malocclusion with deep bite, normal bite, open bite. The distributions of the ODI in different groups were investigated. The specialities of the index in diagnosis for open bite and deep bite were investigated by the overlapping of the distributions between malocclusion with open bite and normal bite and between malocclusion with deep bite and normal bite respectively. Then,to investigate the importance of ODI for clinical application, the specialities were compared with those of some other cephalometric measurements in the occlusion depth diagnosis, such as PP-FH, SN-FH, MP-FH, MP-SN, PP-MP, S-Go/N-Me, and ANS-Me\N-Me.3. 180 lateral cephalometric radiographs from the individuals with corresponding malocclusion were chosen randomly. They were divided into 3 groups as class I, II, andⅢmalocclusion. The distributions of the APDI in different groups were investigated. The specialities of the index in diagnosis for Class II andⅢmalocclusion were investigated by the overlapping of the distributions between Class I andⅡmalocclusion and between class I andⅢmalocclusion respectively. Then,to investigate the importance of APDI for clinical application, the specialities were compared with those of some other cephalometric measurements in the anterio-posterior discrepancy diagnosis, such as AB-PP, ANB, AF-BF, and Wits.Results:1. It was shown that the normal ranges for ODI and APDI in the individuals with normal occlusion in XI'an area were 76.30±4.23°and 83.10±3.90°respectively. It can be used in the orthodontic diagnosis in this area.2. It was shown that the distribution ranges of ODI in malocclusion with deep bite, normal bite and open bite were 78.6±4.5°, 6.6±6.1°, and 69.9±4.8°respectively. The distribution overlapping(63.8%) of ODI between malocclusion with deep bite and normal bite was higher than that of ANS-Me\N-Me(25%), which suggested that the speciality of ODI for deep bite diagoasis was not as good as ANS-Me\N-Me. The distribution overlapping of ODI between malocclusion with open bite and normal bite was 21.8%, which was the most lower overlapping among the cephalometric measurements for occlusion depth diagnosis. It was suggested that the speciality of ODI for open bite diagnosis is best among the indexes compared in this study.3. It was shown that the distribution ranges of APDI in class I,II, andⅢmalocclusion were 82.8±2.8°, 7.9±3.1°, and 88.6±2.8°respectively. The distribution overlapping ( 4.5% ) of APDI between class I andⅢmalocclusion was higher than that of ANB(1.3%), which suggested that the speciality of APDI for classⅢmalocclusion diagnasis was not as good as ANB. The distribution overlapping of APDI between class I and II malocclusion was 10.1%, which was the most lower overlapping among the cephalometric measurements for anterior-posterior discrepancy. It was suggested that the speciality of APDI for class II malocclusion diagnosis is best among the indexes compared in this study. |
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