An inference modeling of human visual judgment of sagittal jaw-base relationships based on cephalometry: part I.

When there appears to be a contradiction between a cephalometric tracing and what is seen, the clinician tends to place more reliance on the appearance of the face in profile than on a formal cephalometric evaluation of the sagittal jaw relationship. With this in mind, we derived a multiple regression model with cephalometric variables to explain the visual influences that affect the subjective classification of sagittal jaw relationships made by experienced orthodontists. The regression model that showed the highest coefficient of determination, 0.90, was constructed from a linear combination of the angle ANB, the anteroposterior position of gnathion, the SN length, and the mandibular body length. The performance reliability of the inference system has been tested for 175 female adult cases and will be reported in Part II of this article.