The Wits appraisal among a Nigerian sub-population: an assessment of dental base geometric factors

The Wits appraisal is a common linear cephalometric analytic tool established by Jacobson. It has been reported to be superior to angular cephalometric measures as it is not dependent on pericranial structures and their variations both during growth and orthodontic treatment. Aim: To obtain reference values for the Wits appraisal among Nigerians and assess the effect of the dental base geometry on it. Methods: Lateral cephalometric radiographs of 100 Nigerian subjects with normal occlusion were analyzed to obtain the Wits appraisal, and the effect of the vertical distance from subspinale to supramentale, length of the palatal and mandibular planes, the mandibular plane angle as well as the palatal plane angle were assessed using the ANOVA and linear regression analysis. Results: The mean age was 20.69 ± 4.9 years. Thirty-four (34%) were males and 66(66%) were females. Mean Wits value of -3.43 ± 3.24 mm was obtained based on the functional occlusal plane (FOP). Linear regression analysis showed that the vertical height from subspinale (A point) to supramentale (B point) caused a significant change in the Wits appraisal reading in participants still undergoing active growth process (less than 16 years of age) (p=0.02). Conclusions: It is advocated that the Wits appraisal be used as a moderator to the ANB angle among Nigerians. However, as a result of dental height variations its use in growing Nigerian children requires caution.