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

AbstractObjectivesTo investigate the accuracy and reliability of implant site measurements, recorded from low-dose cone beam computed tomography (CBCT) images.MethodsCBCT reformatted images of five skulls were obtained using 40, 20 and 7s 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.ResultsThe mean absolute errors from the 40, 20 and 7s protocols were 0.50, 0.46, and 0.51mm, 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.ConclusionsIn imaging of dry skulls, lowering the CBCT exposure time from 40s to 20 or 7s does not affect the reliability or accuracy of implant site measurements

A retrospective study of the prevalence and reliability of the diagnosis of soft tissue calcification of the temporomandibular joint in cone beam computed tomography images

AbstractObjectiveTo investigate the prevalence and reliability of diagnosis of soft tissue calcification of the temporomandibular joint (TMJ) in cone beam computed tomography (CBCT) images of TMJ and non-TMJ patients.Materials and methodsAll retrievable CBCT data sets acquired during a period of 2years and 7months were evaluated for the presence of a soft tissue calcification of the TMJs. Axial and corrected sagittal and coronal images were viewed as 2mm maximum intensity projection images throughout the entire thickness of each joint by a single examiner. Fifty randomly selected cases were examined again by the same examiner using the same protocol. Descriptive statistics were used to calculate the percentage of the cases diagnosed with TMJ soft tissue calcification during both examinations. The chi square test was used to calculate the intra-observer agreement between the two examinations.ResultsThe total sample size was 491 joints. The first and second examinations yielded a diagnosis of calcification present in 12% and 34% of cases, respectively. Cross-tabulation of the results from the first and second examinations indicated 34% of the readings were not in agreement. The chi square test indicated no significant correlation between the results of the first and second examination (p-value=0.626). With regards to the cases diagnosed with calcification, 94% of the cases were in disagreement.ConclusionsThe CBCT images produced by the device used in the present study were of low reliability for the diagnosis of TMJ soft tissue calcification. Studies are needed to develop CBCT protocols which may accurately and reliably demonstrate such calcification

Comparative study of the accuracy of CBCT implant site measurements using different software programs

Purpose: To measure and compare the accuracy of the linear dimensions of implant sites recorded from cone beam computed tomography (CBCT) images using Blue Sky Plan, coDiagnostiX, and RadiAnt. Materials and Methods: Five human dry skulls were imaged with a CBCT device then sectioned to obtain sample transverse cross-sections of the edentulous ridges, and the height and width of the ridge were measured with a digital caliper to provide the gold standard measurements. The CBCT datasets were exported in DICOM format and imported into the three test software programs which were used to obtain reformatted sectional images corresponding to the sample transverse cross-sections, and the height and width of the edentulous ridge was recorded using the linear measurement tool. Reliability of the measurements were measured using the intraclass correlation coefficient. One-sample t-test (test value: zero) was used to test the statistical significance of the mean of the absolute errors for each software program. Analysis of Variance with Repeated Measures was used to test the statistical significance of the difference between the means of the absolute errors obtained by the different software programs. Statistical significance was set at a p-value of 0.05. Results: The reliability of the gold standard and image measurements were excellent. All three software programs demonstrated a statistically significant mean absolute measurement error of between 0.43 and 0.56 mm (p-value < 0.01), but no significant difference in error values was found between any of the tested programs (p- value = 0.18). Conclusions: There was no statistically significant difference in accuracy of linear CBCT measurements of implant sites recorded using Blue Sky Plan, coDiagnostiX, and RadiAnt

Lipoid proteinosis: A case report with recurrent parotitis and intracranial calcifications

AbstractLipoid proteinosis is an autosomal recessive disease of abnormal deposition of glycoprotein in various tissues. Symptoms may include a hoarse voice, lesions and scarring on the skin, easily damaged skin with poor wound healing, dry, wrinkly skin, and beading of the papules around the eyelids. Calcifications of brain tissue can lead to epilepsy and neuropsychiatric abnormalities. In this paper we will review the current literature on the disease and report a case of a 15year old Saudi female with lipoid proteinosis that presented initially with recurrent parotitis

A comparative study of the accuracy and reliability of multidetector computed tomography and cone beam computed tomography in the assessment of dental implant site dimensions

OBJECTIVES: The aim of this study was to investigate the accuracy and reliability of linear measurements of edentulous ridges recorded from 16-row multidetector CT (MDCT) images and cone beam CT (CBCT) images acquired using a flat panel detector (FPD) with a large field of view (FOV), both independently and in comparison with each other. METHODS: Edentulous areas of human dry skulls were marked with gutta-percha markers to standardize the plane of the transverse cross-sections and path of measurements. The skulls were imaged using a 16-row MDCT scanner and a CBCT device with a large FOV and a FPD. Ridge dimensions were recorded from reformatted sections by two observers and compared with measurements recorded directly from the bone. The measurement errors and intra and interexaminer reliability were calculated for each modality and compared with each other. RESULTS: The overall mean of the absolute errors was 0.75 mm for MDCT and 0.49 mm for CBCT. The mean of the CBCT absolute errors was smaller than that of the MDCT absolute errors for the overall data, as well as for the site-specific data. The intraexaminer reliability score was 0.994 for MDCT and 0.995 for CBCT. The interexaminer reliability was 0.985 for MDCT and 0.958 for CBCT. CONCLUSIONS: Both MDCT and CBCT were associated with a clinically and statistically significant measurement error. CBCT measurements were significantly more accurate than those of MDCT. The measurements recorded from both modalities had a high inter and intraexaminer reliability. Accuracy of measurements was found to be more operator dependent with CBCT than with MDCT