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.

PREDICATING THE “WITS” APPRAISAL FROM THE ANB ANGLE / 药物分析学报

Objective In order to explore the relationship between the “Wits" appraisal and the ANB angle, and to see how accurately one can predict the “Wits”. Methods Given the ANB, lateral cephalometric radiographs were taken on 50 boys and 50 girls between the ages of 11～13. Results Each subject had no treatment either a Class Ⅰ or Class Ⅱ malocclusion, a good growth pattern. Group Ⅰ , 13 subjects of 100 had ANB≤1.5°, and negative “Wits” appraisal; group Ⅱ , 61 subjects had 5.8°＞ANB＞1.5°, and “Wits” appraisal either positive or negative; group Ⅲ , 26 subjects had ANB angle≥5.8°, and positive “Wits” appraisal. Statistically analysis showed that there was no sig nificant difference in sex (P＞0.05); there was significant correlation between the ANB and “Wits” values in the group Ⅱ and group Ⅲ (P ＜0. 05); there was statistical significance in regression analysis in the group Ⅰ and group Ⅱ (P ＜0. 05). We could predict the “Wits” with 21％ accuracy in group Ⅱ. Conclusion The results indicate that these figures are statistically significant but clinically irrelevant.