Objective: To determine the association between the anteroposterior relationship of the dental arch and the anteroposterior relationship of the jaw-base in a Chinese population sample.
Materials and methods: Orthodontic casts and lateral cephalograms were obtained from a random sample of 405 twelve-year-old Chinese children from a population survey in Hong Kong. Angle's classification was used to assess the dental arch relationship from orthodontic casts. The jaw-base relationship was assessed from the lateral cephalograms using angular (ANB angle) and linear (Wits analysis) measurements. The correlation between the anteroposterior dental arch and jaw-base relationships was assessed.
Results: The anteroposterior dental arch did coincide with the jaw-base relationships, as expressed by the ANB angle in 61%, the Wits analysis in 67%, and with both in 53%. The jaw-base relationship assessed with the Wits analysis was more significantly associated with the dental arch relationship (P < .001) than that assessed with the ANB angle (P < .01). The correlation coefficient between the ANB angle and the Wits appraisal was .65 for the combined sample, and .60, .64, and .67 for Class I, II, and III dental arch relationships.
Conclusion: In this population, the anteroposterior relationship of the dental arch and jaw-base fail to match in at least one out of every three individuals. Linear measurement of anteroposterior jaw-base relationships is a more valid reflection of the dental arch relationship than angular measurements.