• The korean journal of orthodontics
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• v.29 no.3 s.74
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• pp.349-360
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• 1999

The concept of denture frame, both the vertical and horizontal relationship of the dentitions are ultimately related to a skeletal configuration, leads to postulate that the vertical overbite will be determined by the jaw rotations and anteroposterior jaw relationship. Also, ODI is analyzed to be composed of the determinant factors of overbite such as FMA PPA and FABA. From the geometric analyses of an interrelationship between the ODT and the overbite determinants, the following formula can be induced. ODI norm=$85^{\circ} - 0.5 PMA-(1.08 - 0.01 FMA)(FABA - 81^{\circ})$. This formula indicates that the norm of ODI is not constant value but variable one according to the individual skeletal frames. Through the application of the formula to the various clinical cases, it is proved that the new concept, relativity of the ODI norm, is very diagnostically useful.