An accurate method of predicting mandibular growth potential based on bonematurity

Mandibular growth prediction provides important information for planning tr eatment and for evaluating occlusal stability after treatment. At present, several methods can predict mandibular growth, but it is not clear which me thod is the most accurate. This study compared the predictive error of seve ral methods by using skeletal maturity indicators. Twenty-two longitudinal cephalograms and hand-wrist radiographs of female subjects (average initial age, 8.3 years; final age, 18.4 years) were collected to construct the pre diction formula. Another 22 female subjects (initial age, 10.8 years; final age, 18.6 years) were examined to compare differences between the predicte d values and the actual values. Mandibular total length (condylion-gnathion ) at the final stage can be accurately predicted by (1) the ossification ev ents of the third middle phalanx and the radius, (2) the growth potential m ethod, (3) the growth percentage method, (4) the multiple regression method , and (5) the growth chart method. Bone age as a parameter was calculated b y both the Tanner-Whitehouse 2 (TW2) method and the computer-aided skeletal maturity assessment system (CASMAS) that we developed. The average error b etween the predicted length of condylion to gnathion and the actual length at the final stage for each method was (1) 3.0 mm; (2) 2.1 mm (TW2), 2.4 mm (CASMAS); (3) 2.3 mm (TW2), 2.6 mm (CASMAS); (4) 4.3 mm (TW2), 4.9 mm (CAS MAS); and (5) 3.6 mm (TW2), 3.7 mm (CASMAS). The growth potential method an d the growth percentage method were the most accurate predictors of mandibu lar growth potential.