Cranial base angulation and linear dimensions in Class I, II and III sagittal jaw relationships in a Nigerian population: A cephalometric study

Background: Controversies still exist on the role of cranial base in the classification of jaw discrepancies. This present study was conducted to determine the role of cranial base in the classification of jaw discrepancies among a Nigerian population. Materials and method: This cross-sectional descriptive study involved 209 pre-treatment lateral cephalographs comprising of 79 males and 130 females (aged 7 to 55 years). The A-point- nasion-B point angle (ANB) was used to categorize the sagittal jaw relationship into skeletal patterns I, II and III. One-way ANOVA was applied to test if cranial base angulation and length differ significantly among the skeletal patterns. Pearson’s correlation coefficient was used to test for association between some independent variables. Statistical significance was determined only when p value was < 0 .05 Result: There were no statistically significant differences in the cranial base angle and cranial base lengths in the different skeletal patterns. Negative significant correlations were noted between the cranial base angle and the sella nasion-A point angle (SNA; r= - 0.483; p<0.001) and the sella nasion-B point angle (SNB; r= - 0.439, p<0.001) angles in the different skeletal malocclusion but not with cranial base angle and ANB angle (r= -0.021, P=0.758). In addition, the cranial base length showed positive significant correlation with the effective maxillary length (r= 0.759, p=<0.001) and effective mandibular length in the different skeletal malocclusion morphology (r= 0.718, p<0.001) Conclusion: This study has shown that cranial base angulation and linear dimensions do not play primary aetiological roles in determining the outcome of the sagittal jaw relationships in the different skeletal malocclusion.