Think Mathematic, Gain Orthodontic. Innovative modification of Tonn formula to calculate mesiodistal width of missing lower incisors

The incidence of congenital absence of lower incisors though is statistically low but still is area of concern for orthodontists. Also, chances of losing lower anteriors due to periodontal pathology are high due to its location, which is a concern in adult orthodontics. For the achievement of an ideal occlusion and a good intercuspation, we need to identify the interarch tooth size discrepancy calculated using the individual tooth size. Thereby, in cases with missing lower incisors, considering the tooth size of the missing tooth is questionable. Therefore, we have proposed an innovative mathematical modification of Tonn formula for the prediction of the mesiodistal width of the missing lower anterior tooth. The use of this method in our department is a testimony of its usefulness.