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. 2012 Jul;24(3-4):127-34.
doi: 10.1016/j.sdentj.2012.05.001. Epub 2012 Jun 1.

Effect of exposure time on the accuracy and reliability of cone beam computed tomography in the assessment of dental implant site dimensions in dry skulls

Asmáa A Al-Ekrish  1
Affiliations

Effect of exposure time on the accuracy and reliability of cone beam computed tomography in the assessment of dental implant site dimensions in dry skulls

Asmáa A Al-Ekrish. Saudi Dent J. 2012 Jul.

Abstract

Objectives: To investigate the accuracy and reliability of implant site measurements, recorded from low-dose cone beam computed tomography (CBCT) images.

Methods: CBCT reformatted images of five skulls were obtained using 40, 20 and 7 s exposure protocols. From these protocols, edentulous ridge dimensions were recorded by two observers and compared with measurements recorded directly from the bone. The measurement errors and intra- and inter-examiner reliability were calculated for each exposure protocol and compared with each other.

Results: The mean absolute errors from the 40, 20 and 7 s protocols were 0.50, 0.46, and 0.51 mm, respectively. The intra-examiner reliability scores were 0.996, 0.995 and 0.998, respectively. The inter-examiner reliability scores were 0.993, 0.998 and 0.994, respectively. There was no significant difference in accuracy or reliability between the three protocols.

Conclusions: In imaging of dry skulls, lowering the CBCT exposure time from 40 s to 20 or 7 s does not affect the reliability or accuracy of implant site measurements.

Keywords: CBCT; Dental implantation; Dry skull; Radiation dosage; Reliability.

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Figures

Figure 1
Figure 1
Diagram showing the direction of the height and width measurements on transverse cross-sections. (a) Mandibular section, anterior to the mental foramen. (b) Mandibular section, at and posterior to the mental foramen. (c) Maxillary section.
Figure 2
Figure 2
Sample of reformatted CBCT transverse cross-sectional images (at a window level of 278 and a window width of 2484) obtained using an exposure time of (a) 40 s, (b) 20 s, and (c) 7 s.
Figure 3
Figure 3
Frequency histogram of the measurement error values obtained using a 40 s exposure.
Figure 4
Figure 4
Frequency histogram of the measurement error values obtained using a 20 s exposure.
Figure 5
Figure 5
Frequency histogram of the measurement error values obtained using a 7 s exposure.
Figure 6
Figure 6
Bar chart of the means of the absolute measurement errors (±1 standard error) obtained with the three examination protocols for the entire sample and for the height measurements at the IDC.
None
See this image and copyright information in PMC

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