Comparison of measurements of mandible growth using cone beam computed tomography and its synthesized cephalograms

Abstract

BackgroundThe current study aimed to compare the measurements of the mandible morphology using 3D cone beam computed tomography (CBCT) images with those using 2D CBCT-synthesized cephalograms; to quantify errors in measurements based on 2D synthesized cephalograms; and to clarify the effects such errors have on the description of the mandibular growth.MethodsMandibles of six miniature pigs were scanned monthly using CBCT over 12 months and the data were used to reconstruct the 3D bone models. Five anatomical landmarks were identified on each bone model, and the inter-marker distances and monthly distance changes were calculated and taken as the gold standard. Synthetic 2D cephalograms were also generated for each bone model using a digitally reconstructed radiography (DRR)-generation method. Errors in cephalogram measurements were determined as the differences between the calculated variables in cephalograms and the gold standard. The variations between cephalograms and the gold standard were also compared using paired t-tests.ResultsWhile the inter-marker distance increases varied among the marker pairs, all marker pairs increased their inter-marker distances gradually every month, reaching 50% of the total annual increases during the fourth and fifth months, and then slowing down in the subsequent months. The 2D measurements significantly underestimated most of the inter-marker distances throughout the monitoring period, in most of the monthly inter-marker distance changes during the first four months, and in the total growth (p < 0.05).ConclusionsSignificant errors exist in the measurements using 2D synthesized cephalogram, underestimating the mandibular dimensions and their monthly changes in the early stages of growth, as well as the total annual growth. These results should be considered in dental treatment planning at the beginning of the treatment in order to control more precisely the treatment process and outcome.

Assessing mandibular body changes in growing subjects: a comparison of CBCT and reconstructed lateral cephalogram measurements

“…In fact, the second linear regression (coefficient of ratio = − 1.850, p < 0.001; constant = 0.517, p < 0.001) shows that in the cohort of patients who was analysed, the expected value of distortion in the assessment of mandibular growth ranges between − 0.732 and 0.265 mm, thus showing a result that is not clinically significant. Lin et al 49 affirmed that significant errors exist in the measurements of mandibular body growth using 2D RLCs compared to CBCT in six miniature pigs. Clinical and statistically significant underestimation of the actual growth was reported.…”

“…Lin et al 49 affirmed that significant errors exist in the measurements of mandibular body growth using 2D RLCs compared to CBCT in six miniature pigs. Clinical and statistically significant underestimation of the actual growth was reported.…”

“…Clinical and statistically significant underestimation of the actual growth was reported. Lin et al 49 concluded that this event should be considered in orthodontic treatment planning to more precisely control the treatment process and outcome. However, the present study reveals that within its limitations, the actual linear mandibular body growth in humans during growth spurt is equally evaluated in entity and accuracy with bi-dimensional radiographs.…”

Cephalometric Angular Measurements of the Mandible Using Three-Dimensional Computed Tomography Scans in Koreans

“…The current standard is to use plain lateral and frontal cephalograms for a 2D cephalometric analysis. However, there are well-known limitations to 2D imaging, such as projective displacement, rotational errors, and linear projective transformation, which interfere with the reliability and reproducibility of these measurements [ 6 19 ]. Moreover, most 2D measurements are distorted in the presence of facial asymmetry [ 20 ].…”

Test–retest reliability of mandibular morphology measurements on cone-beam computed tomography-synthesized cephalograms with random head positioning errors

“…By taking advantage of computer simulations, the CBCT data can be used to generate 2D synthesized cephalograms using the technique of digitally reconstructed radiographs (DRR) on which repeated planar measurements are carried out to determine the reliability of the measurements. The DRR technique has been used to study the morphology of human ankles [ 23 ], canine hips [ 24 ] and mandibles [ 9 , 25 ]. With this technique the effects of errors in identifying bony landmarks on the reliability of determining morphological parameter with random head positioning errors could be studied by simulating random head positions without the effects of other factors such as superimposition of craniofacial structures.…”