ABSTRACT
Introduction: The general feature of occlusal curvature,when viewed from the front, consists of a buccal inclinationof the maxillary molars and a lingual inclination of themandibular molars. The fourth key of Andrews six keys ofocclusion is related to the curve of Wilson, describing theposterior inclination of the crowns of the lower posterior teethas a concave curve, setting the molars with a lingual torque.The aim of this study was to measure buccolingual inclinationof maxillary and mandibular first molars in untreated sampleof pre-orthodontic patients.Material and Methods: CBCT scans from 36 untreatedsubjects (26 females and 10 males; average age, 24.6 years) withminimal dental discrepancies, no prior history of orthodontictreatment, minimal dental wear, no posterior crossbite, nocrowns or significant restorations on any first molars, absenceof remaining primary dentition, were selected. The angleswere measured between long axis of each maxillary molar to avertical reference line that was perpendicular to the horizontalreference line and between each mandibular first molar to thesame reference line.Results: The average inclination of maxillary molar was+4.98º ± 4.26º. There was no significant difference betweenthe right and left mean values. The average inclinationof mandibular molar was -13.10º ± 6.10º. There was nosignificant difference between the right and left values.Conclusion: Maxillary and mandibular molars have a naturalcurvature of their inclinations where the maxillary molarshave a slight buccal inclination and mandibular molars have aslight lingual inclination