Assessing incisor inclination: a non-invasive technique.

A method of recording incisor inclination is described using the Tooth inclination Protractor (TIP). This instrument was used to record incisor inclination on dental casts. The scores were related to traditionally determined inclinations for the upper incisor to maxillary plane and the lower incisor to mandibular plane from the lateral cephalometric radiograph. The TIP scores were closely related to the upper incisor to maxillary plane angle and lower incisor to mandibular plane angle. There was a systematic bias between the TIP and radiographically determined assessments. The TIP under-scored the lateral cephalometrically determined maxillary incisor inclination by 10.46 degrees and consistently over-scored the lower mandibular incisor angulation by 2.57 degrees. The TIP is a reliable and valid measure for assessing left and right maxillary and mandibular crown inclinations, and may also be used to record changes of incisor inclination during treatment.