Normal faciolingual inclinations of tooth crowns compared with treatment groups of standard and pretorqued brackets.

Faciolingual inclinations of tooth crowns were measured on plaster casts of normal occlusions and posttreatment orthodontic models of treated cases. Normal anatomic occlusion, standard edgewise and Roth bracket groups of 10 subjects were examined for a change in torque values. On study models, crown inclinations of right and left central teeth to second molar in the upper and lower dental arches were measured to the functional occlusal plane and mean tooth inclinations were calculated. In normal occlusion group, upper central and lateral teeth inclined lingually, lower central teeth inclined slightly labially and lower lateral teeth inclined lingually but the standard deviations of mean values for upper and lower anterior teeth were high. Upper posterior teeth, from canine to molar, had a lingual inclination and lower posterior teeth had a progressively increasing lingual inclination from lateral to molar teeth. In treatment groups, upper central and lateral teeth had labial crown inclination and lower molar teeth had more lingual inclination as compared with the normal occlusion group. No significant variation was found between the mean torque values of standard and Roth treatment groups.