Mixed dentition case analysis-estimating size of unerupted permanent teeth

Abstract

• 1.

  1. The amount of harmony between groups of human mandibular teeth with respect to mesiodistal width is indicated by coefficients of correlation.

• 2.

  2. From the coefficients of correlation there has been derived a predictive graph which makes it possible for one, knowing the sum of the mesiodistal widths of the four mandibular incisors to arrive at the total sum of the mesiodistal widths of the mandibular canine, first premolar, and second premolar of one side.

• 3.

  3. The average error found to arise from the use of this predictive graph was 0.6 mm., or 2.6 per cent. In the same group of cases, using measurements taken from models of the permanent dentition as the correct values, the average error arising from the use of intraoral dental films of average quality taken in the mixed dentition was found to be 2.2 mm. or 10.5 per cent.

• 4.

  4. The predictive graph will give only the sum of the unerupted teeth of one side in the mixed dentition, and does not provide an estimate of the mesiodistal width of any one of the three teeth. As such it is offered as an adjunct to the method of the mixed dentition diagnosis and case analysis of Nance.