Research On The APDI,ODI,CF And EI Of The Individual Normal Occlusion And Malocclusion Of The Youth Of GANSU Province.

The value of APDI, ODI, CF and EI vary a lot among people of different races, regions and ages, so in China some orthodontists have done researches on the standard value of them. At the same time, these values can enable us to estimate comprehensively and roundly the sagittal relations of jaw and between jaw and teeth and they have little normal maximum variation , and a good diagnosis peculiarity. In the oral orthodontics diagnosis, curative effect evaluation and cosmetic surgery, it is a relative perfect metrical criterion to evaluate facial jaw sagittal location relationship and beneficial to the clinical application. Hence it is significant to know the location characteristics of value of APDI, ODI, CF and EI of Gansu individual normal occlusion and malocclusion in order to provide a reference to the diagnosis and treatment of different malocclusion in Gansu.As a result, taking several individual normal occlusions and malocclusion patients' lateral cephalometry as research targets, we applied Winceph 8.0 cephalometric analysis software to analyze them.The main content and results of this research: 1. APDI (Anteroposterior Dyspiasia Indicator)This indicator consists of the summation of facial plane and FH plane angle, AB plane angle, palatal plane and FH plane angle. (When the palatal plane leans downward to the front, the indicator is plus; when the palatal plane leans upward to the front, it is minus; when point B is located behind point A, it is minus ;when point B is located before point A, it is plus.)The abnormity of APDI would lead to the Angle class II and classIII malocclusion.2. ODI (Overbite Depth Indicator)This indicator is made up of the summation of AB plane and submaxilla angle, palatal plane and FH plane angle. (When palatal plane leans downward to the front, the angle is plus; when palatal plane leans upward to the front, the angle is minus) The abnormity of ODI would cause deep overbite or deformity of open bite.3. CF (Combination Factor)The calculation and significance of CF:CF=ODI+APDIThe value of CF is the watershed of case diagnosis for whether to do tooth extraction for the patient or not.4. EI (Extration Index)EI is made on the basis of CF, and combined with the factors of upper—lower middle incisors angle, and the protrusion degree of upper—lower lips. It is an index used to decide whether or not the patient has to have tooth extraction treatment.EI=ODI+| upper—lower middle incisors angle-130|/5(upper—lip protrusion +lower lip protrusion)The result of this research shows the value of APDI, ODI, CF and EI vary a lot among people of different races, regions and ages. What's more, certain difference also exists in different regions of the same race. This research has provided a reference to the diagnosis and treatment of different malocclusion patients in Gansu.