Orthodontic Study Models Equations

Mixed Dentition Analysis

Y1 = (X1 X Y2)/ X2

Tanaka-Johnston Method (Mandibular)

3,4,5 (one quadrant)= (Sum of 4 lower incisors/ 2) + 10.5mm

Tanaka-Johnston Method (Maxillary)

3,4,5 (one quadrant)= (Sum of 4 lower incisors/ 2) + 11.0 mm

Bolton’s Analysis (Overall Ratio)

(Sum of mandibular 12 / Sum of maxillary 12) x 100 = 91.3%

Bolton’s Analysis (Anterior Ratio)

Anterior Ratio = (Sum of mandibular 6 / Sum of maxillary 6) x 100 = 77.2%

Bolton’s Overall ratio

Relative maxillary tooth material excess

< 91.3%

Bolton’s Anterior ratio

Relative maxillary anterior excess

< 77.2%

Bolton’s overall ratio

Normal and Ideal proportion

91.3%

Bolton’s anterior ratio

Normal and Ideal proportion

77.2%

Bolton’s overall ratio

Relative mandibular tooth material excess

>91.3%

Bolton’s anterior ratio

Relative mandibular anterior excess

>77.2%

Pont’s Analysis

Calculated Premolar Value (CPV)

SI x 100/80

Pont’s Analysis

Calculater Molar Value (CMV)

SI x 100/ 64