Comparison of the soft tissue orthodontic analysis measurements between conventional lateral cephalograms and CBCT derived lateral cephalograms.

Conventional lateral cephalograms are ordered for patients even with available Cone-Beam Computed Tomography (CBCT) radiographs which may increase the patient's radiation exposure. According to past studies landmark identification and hard tissue analysis errors on CBCT-derived lateral cephalograms were comparable to those of conventional lateral cephalograms. According to the soft tissue paradigm, diagnosis and treatment planning are based on the soft tissue goals. The aim of this study was to compare the soft tissue analysis between CBCT-derived and conventional lateral cephalograms of the same patient. Twenty-two patients who had both 12-inch CBCT scan (NewTom 3G) and conventional lateral cephalograms available within a 6-month time period were selected. Landmark identification carried out by two operators at the same time for Dolphin imaging software (v11.2). 8 angular and 11 linear soft tissue variables were measured. Paired t-test comparison of two groups revealed no statistically significant differences between the groups except for inclination of nasal base (P<0.05 was considered significant). CBCT-derived lateral cephalograms can be used for the soft tissue analysis as an alternative to conventional lateral cephalograms, when patient's CBCT volume is already available. This can reduce additional X-ray exposure.