Inclination of maxillary and mandibular incisors – comparison of measurements from teleroentgenograms and CBCT

The assessment of incisor location in lateral cephalograms is a standard strategy in orthodontic diagnostics. However, determination of reference points on apices of roots of incisors in the maxilla and mandible is not always precise due to limitations of this examination. CBCT allows to find these points with high precision. Aim. The main aim of the work was to compare measurements of the inclination angle of the most anterior upper incisor to the maxillary base plane (IL+ :NL) and of the lower incisor to the mandibular base plane (IL- :ML) performed in a teleroentgenogram with measurements of the most anterior upper and lower incisors in CBCT. An additional aim was to assess a difference in inclination between the most and the least inclined incisor in the maxilla and mandible in individual patients. Material and methods. Radiological documentation (digital cephalograms and CBCT scans) from 38 patients at the age of 11–46 years (24 females, 14 males) was used in the study. The angle 1+ :NS and 1- :ML were determined in cephalograms for each patient. An angle between the long axis of each maxillary and mandibular incisor and the maxillary base plane and mandibular base plane, respectively, was measured on CBCT scans. The t test for mean pairs was used to compare values of angles obtained in a teleroentgenogram and values of the angle of the most inclined incisor in a CBCT scan. Results. There was a statistically significant difference between the value of the angle 1+ :NS measured in a cephalogram and a value of the angle between the long axis of the most inclined maxillary incisor and the maxillary base plane evaluated in a CBCT scan (p = 0.00). Moreover, there was also a statistically significant difference between the value of the angle 1- :ML measured in a teleroentgenogram and the value of the angle between the long axis of the most inclined mandibular incisor and the mandibular base plane evaluated in a CBCT scan (p = 0.02). Conclusions. 1) The assessment of inclination of maxillary and mandibular incisors in cephalograms is not identical to the assessment of incisor inclination using CBCT scans. 2) CBCT is recommended in order to assess this parameter precisely due to great differences between measurements of the inclination angle of individual incisors in the maxilla and mandible. (Kalina E, Sobieska E, Kalina K, Zadurska M. Inclination of maxillary and mandibular incisors – comparison of measurements from teleroentgenograms and CBCT. Orthod Forum 2017; 13: 89-96).