Original article
Comparison of cephalometric measurements and cone-beam computed tomography-based measurements of palatal bone thickness

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Introduction

The purpose of this study was to determine the relationships between cephalometric measurements and cone-beam computed tomography-based measurements of the palatal bone thickness.

Methods

Thirty sets of cone-beam computed tomography images and lateral cephalograms were used. Palatal bone thicknesses were measured anteroposteriorly from between the first and second premolars to between the first and second molars using both imaging methods, and also laterally from 1.5 mm off-center to 10 mm off-center in the cone-beam computed tomography images. Repeated-measures analysis of variance was used to examine the differences between the measurements.

Results

Bland-Altman plots showed that the 95% limits of agreement were smallest at 5 mm off-center (−0.2 ± 1.7 mm). The 5-mm off-center measurements were the only ones for which there were no statistically significant differences compared with the cephalometric measurements in all anteroposterior areas. The measurements at 1.5 mm off-center were significantly thicker than the cephalometric measurements only from the area between the second premolar and the first molar to the area between the first and second molars.

Conclusions

Among the areas measured, the bone at 5 mm off-center is most likely to be depicted in cephalograms as palatal bone contours.

Section snippets

Material and methods

This study was approved by the local ethics committee of School of Dentistry, Chosun University, Gwangju, Korea (CDMDIRB 1218-86). Thirty sets of CBCT images and cephalograms (for 15 male and 15 female subjects) were selected from among the CBCT and cephalogram sets from patients for whom CBCT was performed during an orthodontic examination (Table I). The exclusion criteria included pathologic findings, cleft palate, missing or supernumerary teeth, and previous orthodontic treatment. The

Results

The incisive canal was encountered in 60% of P1P2, 13% of P2, and 3% of P2M1 measurements in the CBCT images at 1.5 mm off-center. The maxillary sinus was encountered in 57% of 10-mm off-center measurements and in 20% of 7.5-mm off-center measurements (Table III).

In Bland-Altman plots, the limits of agreement were defined as ±1.96 SD, and the 95% confidence interval (CI) values for the limits of agreement were identified (Fig 4). The 95% limits of agreement were 0.9 ± 3.1 mm (mean, ±1.96 SD)

Discussion

The null hypothesis was rejected in favor of an alternative hypothesis that there is a strong correlation between cephalometric measurements and CBCT-based measurements of the palate, especially at 5 and 7.5 mm off-center (Fig 4). In the Bland-Altman plots,16, 17 the 5-mm and 7.5-mm off-center measurements showed minimal mean differences and relatively small limits of agreement, with the smallest limits of agreement at 5 mm off-center (−0.2 ± 1.7 mm). This indicates that the bone at 5 mm

Conclusions

Among the areas measured in this study, the palatal bone at 5 mm off-center is most likely to be depicted in cephalograms as palatal bone contours. Bone at 1.5 mm off-center is thicker than shown on cephalograms in the areas from P2M1 to M1M2 because of the increasing height of the nasal crest.

References (17)

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All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest, and none were reported.

Supported by research funding from Chosun University, 2012.

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