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1.  Assessment of endodontically treated teeth by using different radiographic methods: an ex vivo comparison between CBCT and other radiographic techniques 
Imaging Science in Dentistry  2012;42(3):129-137.
To compare different radiographic methods for assessing endodontically treated teeth.
Materials and Methods
Root canal treatments were applied in 120 extracted mandibular teeth, which were divided into four groups: (1) ideal root canal treatment (60 teeth), (2) insufficient lateral condensation (20 teeth), (3) root canals filled short of the apex (20 teeth), (4) overfilled root canal treatment (20 teeth). The teeth were imaged using intraoral film, panoramic film, digital intraoral systems (CCD and PSP), CCD obtained with portable X-ray source, digital panoramic, and CBCT images obtained at 0.3 mm3 and 0.2 mm3 voxel size. Images were evaluated separately by three observers, twice. Kappa coefficients were calculated. The percentage of correct readings obtained from each modality was calculated and compared using a t-test (p<0.05).
The intra-observer kappa for each observer ranged between 0.327 and 0.849. The inter-observer kappa for each observer for both readings ranged between 0.312 and 0.749. For the ideal root canal treatment group, CBCT with 0.2 mm3 voxel images revealed the best results. For insufficient lateral condensation, the best readings were found with periapical film followed by CCD and PSP. The assessment of teeth with root canals filled short of the apex showed the highest percentage of correct readings by CBCT and CCD. For the overfilled canal treatment group, PSP images and conventional periapical film radiographs had the best scores.
CBCT was found to be successful in the assessment of teeth with ideal root canal treatment and teeth with canals filled short of the apex.
PMCID: PMC3465754  PMID: 23071962
Root Canal Therapy; Radiography, Dental; Cone-Beam Computed Tomography
2.  Ex vivo comparison of Galileos cone beam CT and intraoral radiographs in detecting occlusal caries 
Dentomaxillofacial Radiology  2012;41(6):489-493.
The aim of this study was to compare the accuracy of cone beam CT (CBCT) with intraoral radiographs for detection of occlusal caries.
A set of 60 extracted teeth were imaged using a Sirona Galileos CBCT system (Sirona Dental Systems, Bensheim, Germany) and an intraoral Planmeca® system (Planmeca OY, Helsinki, Finland). Six observers looked at both modalities and used a five-point confidence scale to evaluate presence or absence of occlusal caries. Histology was used as the gold standard. Receiver operating characteristic analysis and weighted kappa statistics were used for statistical analysis. Differences in the area under the curve (AUC) values between observers and modalities were analysed using analysis of variance (ANOVA). Differences in sensitivity and specificity were analysed using the Wilcoxon test. Interobserver and intraobserver reliability was assessed by weighted kappa scores.
The mean value and standard deviation of AUC was 0.719 ± 0.038 for CBCT and 0.649 ± 0.062 for the intraoral radiographs. The ANOVA results demonstrated that there was no significant difference between the modalities and the observers. The interobserver kappa for pairs of observers ranged from fair to substantial for bitewings (0.244–0.543) and CBCT (0.152–0.401). Four out of six observers reported higher sensitivity but lower specificity with CBCT. The Wilcoxon exact p-value showed no difference in sensitivity (0.175) or specificity (0.573) between the two modalities.
Based on the results we conclude that the Sirona CBCT unit cannot be used for the sole purpose of looking at occlusal caries.
PMCID: PMC3520394  PMID: 22184471
caries; cone beam computed; cone beam computed tomography; dental; tomography
3.  Diagnostic accuracy of different imaging modalities in detection of proximal caries 
Dentomaxillofacial Radiology  2010;39(8):501-511.
The purpose of this study was to assess the in vitro diagnostic ability of visual inspection, film, charge-coupled device (CCD) sensor, photostimulable phosphor (PSP) sensor and cone beam CT in the detection of proximal caries in posterior teeth compared with the histological gold standard.
Visual inspection, film, CCD, PSP and cone beam CT images were used to detect proximal caries in the mesial and distal surfaces of 138 teeth (276 surfaces). Visual inspection and evaluation of all intraoral digital and conventional radiographs and cone beam CT images were performed twice by three oral radiologists. Weighted kappa coefficients were calculated to assess intra- and interobserver agreement for each image set, and scores were compared with the histological gold standard using receiver operating characteristic (ROC) analysis to evaluate diagnostic ability.
Intraobserver kappa coefficients calculated for each observer for each method of detecting caries ranged from 0.739 to 0.928. Strong interobserver agreement ranging from 0.631 to 0.811 was found for all detection methods. The highest Az values for all three observers were obtained with the cone beam CT images; however, differences between detection methods were not statistically significant (P > 0.05).
Visual inspection, film, CCD, PSP plates and cone beam CT performed similarly in the detection of proximal caries.
PMCID: PMC3520212  PMID: 21062944
detection; cone beam computed tomography; digital radiography; film; proximal caries
4.  Semi-automatic volumetric tumor segmentation for hepatocellular carcinoma: Comparison between C-arm Cone Beam Computed Tomography and MRI 
Academic radiology  2013;20(4):446-452.
Rationale and Objectives
To evaluate the precision and reproducibility of a semi-automatic tumor segmentation software in measuring tumor volume of hepatocellular-carcinoma–(HCC) before the first trans-arterial chemo-embolization–(TACE) on contrast-enhancement magnetic-resonance-imaging–(CE-MRI) and intra-procedural dual-phase C-arm cone-beam computed-tomography–(DP-CBCT) images.
Materials and Methods
19HCCs were targeted in 19patients(one per patient) who underwent baseline diagnostic CE-MRI and an intra-procedural DP-CBCT. The images were obtained from CE-MRI–(arterial-phase of an intra-venous contrast medium injection) and DP-CBCT–(delayed-phase of an intra-arterial contrast medium injection) before the actual embolization. Three readers measured tumor volumes using a semi-automatic 3D-volumetric segmentation software which used a region-growing method employing non-Euclidean radial basis functions. Segmentation time and spatial position were recorded. The tumor volume measurements between images sets were compared using linear-regression and Student t-test, and evaluated with Intraclass-Correlation analysis–(ICC). The inter-rater Dice Similarity Coefficient–(DSC) accessed the segmentation spatial localization.
All 19 HCCs were analyzed. On CE-MRI and DP-CBCT examinations respectively, A) the mean segmented tumor volumes was 87±8cm3[2–873] and 92±10cm3[1–954], with no statistical difference of segmented volumes by readers of each tumor between the two imaging modalities and the mean time required for segmentation was 66±45seconds [21–173] and 85±34seconds[17–214] (p=0.19), B),the ICCs were 0.99 and 0.974, showing a strong correlation among readers, and C) the inter-rater DSCs showed a good to excellent inter-user agreement on the spatial localization of the tumor segmentation–(0.70±0.07 and 0.74±0.05,p=0.07).
This study shows a strong correlation, precision and reproducibility of semi-automatic tumor segmentation software in measuring tumor volume on CE-MRI and DP-CBCT images. The use of the segmentation software on DP-CBCT and CE-MRI can be a valuable and highly accurate tool to measure the volume of hepatic tumors.
PMCID: PMC3602801  PMID: 23498985
Tumor segmentation software; Dice Similarity Coefficient; C-arm cone-beam CT; MRI; Hepatocellular carcinoma; TACE
5.  Influence of cone beam CT scanning parameters on grey value measurements at an implant site 
Dentomaxillofacial Radiology  2013;42(3):79884780.
The aim of this study was to determine the grey value variation at the implant site with different scan settings, including field of view (FOV), spatial resolution, number of projections, exposure time and dose selections in two cone beam CT (CBCT) systems and to compare the results with those obtained from a multislice CT system.
A partially edentulous human mandibular cadaver was scanned by three CT modalities: multislice CT (MSCT) (Philips, Best, the Netherlands), and two CBCT systems: (Accuitomo 170®, Morita, Japan) and (NewTom 5G®, QR, Verona, Italy). Using different scan settings 36 and 24 scans were obtained from the Accuitomo and the NewTom, respectively. The scans were converted to digital imaging and communications in medicine 3 format. The analysis of the data was performed using 3Diagnosys® software (v. 3.1, 3diemme, Cantù, Italy) and Geomagic studio® 2012 (Morrisville, NC). On the MSCT scan, one probe designating the site for pre-operative implant placement was inserted. The inserted probe on MSCT was transformed to the same region on each CBCT scan using a volume-based three-dimensional registration algorithm. The mean voxel grey value of the region around the probe was derived separately for each CBCT. The influence of scanning parameters on the measured mean voxel grey values was assessed.
Grey values in both CBCT systems significantly deviated from Hounsfield unit values measured with MSCT (p = 0.0001). In both CBCT systems, scan FOV and spatial resolution selections had a statistically significant influence on grey value measurements (p = 0.0001). The number of projections selection had a statistically significant influence in the Accuitomo system (p = 0.0001) while exposure time and dose selections had no statistically significant influence on grey value measurements in the NewTom (p = 0.43 and p = 0.37, respectively).
Grey-level values from CBCT images are influenced by device and scanning settings.
PMCID: PMC3667541  PMID: 22933535
cone beam CT; registration; grey values; bone density
6.  Accuracy of CBCT Measurements of a Human Skull 
Journal of Digital Imaging  2010;24(5):787-793.
The purpose of this study is to assess the accuracy and reproducibility of cone-beam computed tomography (CBCT) measurements of a human dry skull by comparing them to direct digital caliper measurements. Heated gutta-percha was used to mark 13 specific distances on a human skull, and the distances were directly measured using a digital caliper and on CBCT images obtained with Iluma (3M Imtec, OK, USA) and 3D Accuitomo 170 (3D Accuitomo; J Morita Mfg. Corp., Kyoto, Japan) CBCT imaging systems. Iluma images were obtained at 120 kVp and 3.8 mA and reconstructed using voxel sizes of 0.2 and 0.3 mm3. Accuitomo images were obtained at 60 kVp and 2 mA and a voxel size of 0.250 mm3. In addition, 3-D reconstructions were produced from images obtained from both systems. All measurements were made independently by three trained observers and were repeated after an interval of 1 week. Agreement between observers and image type was assessed by calculating Pearson correlation coefficients, with a level of significance set at p < 0.05. Pearson correlation coefficients between readings ranged from 0.995 to 1 for all image types. Correlations among observers were also very high, ranging from 0.992 to 1 for the first reading and from 0.992 to 1 for the second reading for the different image types. All CBCT image measurements were identical and highly correlated with digital caliper measurements. Accuracy of measurements of various distances on a human skull obtained from different CBCT units and image types is comparable to that of digital caliper measurements.
PMCID: PMC3180546  PMID: 20857166
CBCT; Direct measurement; Radiography; 3-D imaging (imaging, three-dimensional); 3-D reconstruction; Automated measurement; Computed tomography
7.  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 
Dentomaxillofacial Radiology  2011;40(2):67-75.
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.
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.
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.
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.
PMCID: PMC3520306  PMID: 21239568
cone beam CT; spiral CT; dental implants; reproducibility of results
8.  Evaluation of Cone Beam Computed Tomography (CBCT) System: Comparison with Intraoral Periapical Radiography in Proximal Caries Detection 
Background and aims
With the introduction of Cone Beam Computed Tomography (CBCT) in dentistry, a question has been raised whether the technique significantly increases the diagnostic accuracy in comparison with other techniques or not. Therefore, the present study was undertaken to assess the accuracy of CBCT modality in detecting proximal carious lesions as compared to conventional periapical radiographs.
Materials and methods
This diagnostic study was carried out on 84 human extracted molars and premolars. The teeth were mounted and divided in 28 blocks of 3 teeth. Periapical and CBCT images of teeth were obtained. Five observers scored the images for the detection of proximal carious lesions using a 2-point scale (caries, present; caries, absent). The gold standard was determined by histopathologic sections. Sensitivity, specificity, PPV, NPV and receiver operating charac-teristics (ROC) curves were traced for observers in both systems. The results were analyzed by paired t-test.
The area under the ROC curve, sensitivity, specificity, accuracy, positive and negative predictive values of CBCT images were 0.568, 0.835, 0.637, 0.714, 0.598 and 0.856, respectively. These parameters were 0.432, 0.837, 0.722, 0.77, 0.687 and 0.858 for the periapical conventional technique, respectively.
The CBCT images did not enhance detection of proximal caries in comparison with periapical images.
PMCID: PMC3442440  PMID: 22991626
Cone Beam CT; periapical imaging; proximal caries
9.  A comparative study of accuracy of linear measurements using cone beam and multi-slice computed tomographies for evaluation of mandibular canal location in dry mandibles 
Dental Research Journal  2013;10(1):15-19.
Cross- sectional tomograms have been used for optimal pre-operative planning of dental implant placement. The aim of the present study was to assess the accuracy of Cone Beam Computed Tomography (CBCT) measurements of specific distances around the mandibular canal by comparing them to those obtained from Multi-Slice Computed Tomography (MSCT) images.
Materials and Methods:
Ten hemi-mandible specimens were examined using CBCT and MSCT. Before imaging, wires were placed at 7 locations between the anterior margin of the third molar and the anterior margin of the second premolar as reference points. Following distances were measured by two observers on each cross-sectional CBCT and MSCT image: Mandibular Width (W), Length (L), Upper Distance (UD), Lower Distance (LD), Buccal Distance (BD), and Lingual Distance (LID). The obtained data were evaluated using SPSS software, applying paired t-test and intra-class correlation coefficient (ICC).
There was a significant difference between the values obtained by MSCT and CBCT measurement for all areas such as H, W, UD, LD, BD, and LID, (P < 0.001), with a difference less than 1 mm. The ICC for all distances by both techniques, measured by a single observer with a one week interval and between 2 observers was 99% and 98%, respectively. Comparing the obtained data of both techniques indicates that the difference between two techniques is 2.17% relative to MSCT.
The results of this study showed that there is significant difference between measurements obtained by CBCT and MSCT. However, the difference is not clinically significant.
PMCID: PMC3714818  PMID: 23878558
Cone beam computed tomography linear measurements; multi-slice computed tomography
10.  Assessment of vertical root fractures using three imaging modalities: cone beam CT, intraoral digital radiography and film 
Dentomaxillofacial Radiology  2012;41(2):91-95.
The aim of this study was to assess the accuracy of cone beam CT (CBCT) in detecting vertical root fractures and to compare the accuracy with images from an intraoral sensor and from conventional intraoral film.
60 extracted, single-rooted human teeth were divided equally into two groups: a control group of 30 teeth and an induced fracture group of 30 teeth. All teeth were randomly placed into sockets in six dry mandibles. Each tooth was imaged by three modalities: CBCT, intraoral digital radiography and intraoral F-speed film. Three beam angulations (an orthogonal projection and additional projections with ±20° horizontal shifts of the central ray) were used when radiographs were made using film and a digital sensor. Three oral and maxillofacial radiologists evaluated the presence of root fractures twice in each image modality using a five-point confidence rating scale. Areas under receiver operating characteristic curves (Az) were computed for each observer and modality and were tested for statistical differences using the Kruskal–Wallis test.
There was no statistical difference in the performance of the three modalities (mean of Az values: CBCT = 0.811, film = 0.797 and sensor = 0.775; p = 0.771).
There was no significant difference between intraoral film, a high-resolution complementary metal oxide semiconductor digital imaging system and CBCT in detecting vertical root fractures in mandibular single-rooted teeth.
PMCID: PMC3520378  PMID: 22301636
cone beam computed tomography; vertical root fracture
11.  Diagnostic Accuracy of Digital and Conventional Radiography in the Detection of Non-Cavitated Approximal Dental Caries 
Iranian Journal of Radiology  2012;9(1):17-21.
Radiography plays an important role in the detection of interproximal caries.
The aim of the present study was to determine diagnostic accuracy of chargecoupled devices (CCD), Photo Stimulable Phosphor (PSP) and film radiography in detecting non-cavitated caries.
Patients and Methods
Seventy-two non-cavitated approximal surfaces of extracted human posterior teeth were radiographed under standardized conditions using three intraoral modalities: CCD Dixi3 (Planmeca, Finland), PSP Digora PCT (Soredex, Finland),and E-speed film (Kodak, USA). Radiographs were interpreted by four observers and caries lesions were classified as sound (R0), restricted to enamel (R1), reaching the dentinoenamel junction (DEJ) and the outer half of the dentin (R2) and the inner half of the dentin (R3). The teeth were subsequently sectioned for histological analysis which served as the gold standard for radiographic examination.
Microscopic examinations showed that the distribution of caries were 63.9% sound, 18.1% enamel, 9.7% DEJ and outer half of the dentin and 8.3% into the inner half of the dentin.
The sensitivity and specificity of film, CCD and PSP for the detection of enamel caries were 38% and 98%; 15% and 96 %; and 23% and 98%, respectively.
The sensitivity and specificity of film, CCD and PSP for the detection of both dentin and enamel caries were 55% and 100%; 45% and 100% ; and 55% and 100%, respectively.
The results demonstrated that the diagnostic accuracy of digital images is similar to that of conventional film radiography in the detection of non-cavitated approximal caries.
PMCID: PMC3522338  PMID: 23329955
Radiography, Dental, Digital; Dental Caries; Diagnosis
12.  Diagnostic performance of cone-beam computed tomography on detection of mechanically-created artificial secondary caries 
Imaging Science in Dentistry  2011;41(4):143-150.
The aim of this study was to compare the diagnostic accuracy of cone-beam computed tomography (CBCT) images and bitewing images in detection of secondary caries.
Materials and Methods
One hundred and twenty proximal slots of Class II cavities were randomly prepared on human premolar and molar teeth, and restored with amalgam (n=60) and composite resin (n=60). Then, artificial secondary caries lesions were randomly created using round steel No. 4 bur. The teeth were radiographed with a conventional bitewing technique and two CBCT systems; Pax-500ECT and Promax 3D. All images were evaluated by five observers. The area under the receiver operating characteristic (ROC) curve (Az) was used to evaluate the diagnostic accuracy. Significant difference was tested using the Friedman test (p value<0.05).
The mean Az values for bitewing, Pax-500ECT, and Promax 3D imaging systems were 0.882, 0.995, and 0.978, respectively. Significant differences were found between the two CBCT systems and film (p=0.007). For CBCT systems, the axial plane showed the greatest Az value.
Based on the design of this study, CBCT images were better than bitewing radiographs in detection of secondary caries.
PMCID: PMC3251786  PMID: 22232722
Dental Caries; Cone Beam CT; Radiography, Bitewing; Diagnosis
13.  Radiographic detection of artificially created horizontal root fracture using different cone beam CT units with small fields of view 
Dentomaxillofacial Radiology  2013;42(4):20120261.
To compare limited cone beam computerized tomography (CBCT) units with different field of views (FOVs) and voxel sizes in detecting artificially created horizontal root fracture (HRF) in extracted human teeth.
Artificial HRF was created in the horizontal plane in 40 teeth. Another 40 intact teeth served as a control group. 80 teeth were placed in the respective maxillary anterior sockets of a human dry skull in groups. Six image sets were obtained: (1) Accuitomo 170, 40 × 40 mm FOV (0.080 mm3); (2) Accuitomo 170, 60 × 60 mm FOV (0.125 mm3); (3) Kodak 9000, 50 × 37 mm FOV (0.076 mm3); (4) Kodak 9000, 50 × 37 mm FOV (0.100 mm3); (5) Vatech Pax-Duo3D 50 × 50 mm FOV (0.080 mm3) and (6) Vatech Pax-Duo3D 85 × 85 mm FOV (0.120 mm3). Images were evaluated twice by five observers. Kappa values were calculated for observer agreement. Areas under the receiver operating characteristic (ROC) curves (Az values) were calculated, and the Az values for each image type were compared using t-tests (α = 0.05).
Intraobserver kappa coefficients ranged from 0.81 to 0.95 for the Accuitomo 170 images, from 0.80 to 0.92 for the Kodak 9000 images and from 0.76 to 0.95 for Vatech PanX-Duo3D. The Az values for different image types and observers ranged from 0.93 to 0.97 for Accuitomo 170 images, from 0.93 to 0.98 for Kodak 9000 images and from 0.93 to 0.97 for the Vatech PanX-Duo3D images. No statistically significant differences (p > 0.05) were found between the Az values.
Limited CBCT units performed similarly in detecting simulated HRF.
PMCID: PMC3667510  PMID: 23420851
horizontal root fracture; CBCT; detection; radiography
14.  Comparison of digital systems and conventional dental film for the detection of approximal enamel caries 
Dentomaxillofacial Radiology  2010;39(7):431-436.
The aims of this study were (1) to compare the accuracy of the detection of approximal enamel caries lesions using three intraoral storage phosphor plate digital systems and one conventional film-based radiographic system; and (2) to determine whether there is a correlation between the histological and radiographic measurements of enamel caries.
160 approximal surfaces were radiographed under standardized conditions using three storage phosphor stimulable systems (DenOptix and Digora FMX with white and blue plates), and one film system (Insight film). 17 observers scored the images for the presence and depth of caries using a 4-point scale. The presence of caries was validated histologically (gold standard). Two-way analysis of variance was used to test the differences in sensitivity, specificity and overall accuracy (TP + TN). The data from the radiographic and histological measurements were statistically analysed by Spearman’s rank correlation coefficient.
Two-way analysis of variance and the post hoc t-test demonstrated that Digora (white plate) had higher specificity and overall accuracy values than DenOptix (P = 0.021); there was no statistically significant difference among the other imaging modalities (P > 0.05). There was no significant correlation between the histological depth measurements and the radiographic measurements from Digora (blue plate) (P = 0.43), Digora (white plate) (P = 0.15), DenOptix (P = 0.17) and Insight film (P = 0.06).
The results suggest that (1) the performance of the three storage phosphor image plate systems was similar to that of the Insight film for detection of approximal enamel caries, and (2) the increase in histological depth of enamel caries was not significantly correlated with radiographic measurements.
PMCID: PMC3520190  PMID: 20841461
radiography, dental; digital radiography, dental; dental caries
15.  A study on the reproducibility of cephalometric landmarks when undertaking a three-dimensional (3D) cephalometric analysis 
Objectives: Cone Beam Computerized Tomography (CBCT) allows the possibility of modifying some of the diagnostic tools used in orthodontics, such as cephalometry. The first step must be to study the characteristics of these devices in terms of accuracy and reliability of the most commonly used landmarks. The aims were 1- To assess intra and inter-observer reliability in the location of anatomical landmarks belonging to hard tissues of the skull in images taken with a CBCT device, 2- To determine which of those landmarks are more vs. less reliable and 3- To introduce planes of reference so as to create cephalometric analyses appropriated to the 3D reality. Study design: Fifteen patients who had a CBCT (i-CAT®) as a diagnostic register were selected. To assess the reproducibility on landmark location and the differences in the measurements of two observers at different times, 41 landmarks were defined on the three spatial axes (X,Y,Z) and located. 3.690 measurements were taken and, as each determination has 3 coordinates, 11.070 data were processed with SPSS® statistical package. To discover the reproducibility of the method on landmark location, an ANOVA was undertaken using two variation factors: time (t1, t2 and t3) and observer (Ob1 and Ob2) for each axis (X, Y and Z) and landmark. The order of the CBCT scans submitted to the observers (Ob1, Ob2) at t1, t2, and t3, were different and randomly allocated. Multiple comparisons were undertaken using the Bonferroni test. The intra- and inter-examiner ICC´s were calculated. Results: Intra- and inter-examiner reliability was high, both being ICC ≥ 0.99, with the best frequency on axis Z. Conclusions: The most reliable landmarks were: Nasion, Sella, Basion, left Porion, point A, anterior nasal spine, Pogonion, Gnathion, Menton, frontozygomatic sutures, first lower molars and upper and lower incisors. Those with less reliability were the supraorbitals, right zygion and posterior nasal spine.
Key words:Cone Beam Computed Tomography, cephalometry, landmark, orthodontics, reliability.
PMCID: PMC3476034  PMID: 22322503
16.  Evaluation of inter-fraction and intra-fraction errors during volumetric modulated arc therapy in nasopharyngeal carcinoma patients 
This prospective study was conducted to evaluate inter- and intra-fraction errors in nasopharyngeal carcinoma (NPC) patients undergoing volumetric modulated arc therapy (VMAT) using cone-beam computed tomography (CBCT) and to thus obtain planning target volume (PTV) margins to effectively guide treatment in the future.
Fifteen NPC patients scheduled to undergo VMAT were prospectively enrolled in the study. For each patient, three CBCT scans were obtained; one after daily conventional positioning, one after online correction with 2 mm tolerance and one after 1 week of VMAT delivery. The scans were registered to the planning CT to determine the inter- and intra-fraction errors. Patient positioning errors were analyzed for time trends over the course of radiotherapy. PTV margins were calculated from the systematic (Σ) and random (σ) errors.
The average absolute values of the pre-correction, post-correction and intra-fraction errors (in order) were 1.1, 0.6 and 0.4 mm in the medial–lateral (ML) direction, 1.2, 0.7 and 0.5 mm in the superior–inferior (SI) direction and 1.1, 0.7 and 0.5 mm in the anterior–posterior (AP) direction. The corresponding Σ were 1.0–1.4 mm, 0.4–0.5 mm and 0.2–0.4 mm, while the corresponding σ were 0.7–0.8 mm, 0.6–0.7 mm and 0.5–0.6 mm. With time, gradual increases in both the inter- and intra-fraction three-dimensional displacements were observed (P = 0.019 and P = 0.044, respectively). The total PTV margins accounting for pre-correction and intra-fraction errors were 3.4–4.1 mm and those accounting for post-correction and intra-fraction errors were 1.7–2.2 mm.
CBCT is an effective modality to evaluate and improve the accuracy of VMAT in NPC patients. Inter- and intra-fraction three-dimensional displacements increased as a function of time during the course of radiotherapy. In our institution, we recommend a PTV margin of 5 mm for NPC patients undergoing VMAT without CBCT and 3 mm for those treated with rigorous daily CBCT scans.
PMCID: PMC3627906  PMID: 23547760
Cone-beam computed tomography; Setup error; PTV margins; Nasopharyngeal carcinoma; Volumetric modulated arc therapy
17.  Comparison of caries detection methods using varying numbers of intra-oral digital photographs with visual examination for epidemiology in children 
BMC Oral Health  2013;13:6.
This was a method comparison study. The aim of study was to compare caries information obtained from a full mouth visual examination using the method developed by the British Association for the Study of Community Dentistry (BASCD) for epidemiological surveys with caries data obtained from eight, six and four intra-oral digital photographs of index teeth in two groups of children aged 5 years and 10/11 years.
Five trained and calibrated examiners visually examined the whole mouth of 240 5-year-olds and 250 10-/11-year-olds using the BASCD method. The children also had intra-oral digital photographs taken of index teeth. The same 5 examiners assessed the intra-oral digital photographs (in groups of 8, 6 and 4 intra-oral photographs) for caries using the BASCD criteria; dmft/DMFT were used to compute Weighted Kappa Statistic as a measure of intra-examiner reliability and intra-class correlation coefficients as a measure of inter-examiner reliability for each method. A method comparison analysis was performed to determine the 95% limits of agreement for all five examiners, comparing the visual examination method with the photographic assessment method using 8, 6 and 4 intra-oral photographs.
The intra-rater reliability for the visual examinations ranged from 0.81 to 0.94 in the 5-year-olds and 0.90 to 0.97 in the 10-/11-year-olds. Those for the photographic assessments in the 5-year-olds were for 8 intra-oral photographs, 0.86 to 0.94, for 6 intra-oral photographs, 0.85 to 0.98 and for 4 intra-oral photographs, 0.80 to 0.96; for the 10-/11-year-olds were for 8 intra-oral photographs 0.84 to 1.00, for 6 intra-oral photographs 0.82 to 1.00 and for 4 intra-oral photographs 0.72 to 0.98. The 95% limits of agreement were −1.997 to 1.967, -2.375 to 2.735 and −2.250 to 2.921 respectively for the 5-year-olds and −2.614 to 2.027, -2.179 to 3.887 and −2.594 to 2.163 respectively for the 10-/11-year-olds.
The photographic assessment method, particularly assessment of 8 intra-oral digital photographs is comparable to the visual examination method in the primary dentition. With the additional benefits of archiving, remote scoring, allowing multiple scorers to score images and enabling longitudinal analysis, the photographic assessment method may be used as an alternative caries detection method in the primary dentition in situations where the visual examination method may not be applicable such as when examiner blinding is required and in practice based randomised controlled trials (RCTs).
PMCID: PMC3549278  PMID: 23312001
Intra-oral photographs; Caries; Visual examination; Dental epidemiology
18.  In Vitro Detection of Dental Root Fractures with Cone Beam Computed Tomography (CBCT) 
Iranian Journal of Radiology  2014;11(1):e11485.
Since the diagnosis of non-displaced longitudinal fractures present difficulties for the dentist, three-dimensional evaluation is necessary.
The aim of this study is to demonstrate the accuracy of cone beam computed tomography (CBCT) in detecting dental root fractures in vitro.
Materials and Methods:
An in vitro model consisting of 210 recently extracted human mandibular teeth was used. Root fractures were created by mechanical force. The teeth were placed randomly in the empty dental alveoli of a dry human mandible and 15 different dental arcs were created. Images were taken with a unit Iluma ultra cone-beam CT scanner (Imtec Corporation, Germany). Three dental radiologists separately evaluated the images.
According to the fracture types and fracture presence, there was an overall statistically significant agreement between the key and readings. Kappa values for intra observer agreement ranged between 0.705 and 0.804 indicating that each observer gave acceptable ratings for the type and presence of fractures.
Detailed information about root fractures may be obtained using CBCT.
PMCID: PMC3955851  PMID: 24693295
Tooth Fractures; In Vitro; Cone-Beam Computed Tomography
19.  Detection of cavitated approximal surfaces using cone beam CT and intraoral receptors 
Dentomaxillofacial Radiology  2013;42(1):20120019.
The aim of this study was to compare cone beam CT (CBCT) in a small field of view (FOV) with a solid-state sensor and a photostimulable phosphor plate system for detection of cavitated approximal surfaces.
257 non-filled approximal surfaces from human permanent premolars and molars were recorded by two intraoral digital receptors, a storage phosphor plate (Digora Optime, Soredex) and a solid-state CMOS sensor (Digora Toto, Soredex), and scanned in a cone beam CT unit (3D Accuitomo FPD80, Morita) with a FOV of 4 cm and a voxel size of 0.08 mm. Image sections were carried out in the axial and mesiodistal tooth planes. Six observers recorded surface cavitation in all images. Validation of the true absence or presence of surface cavitation was performed by inspecting the surfaces under strong light with the naked eye. Differences in sensitivity, specificity and agreement were estimated by analysing the binary data in a generalized linear model using an identity link function.
: A significantly higher sensitivity was obtained by all observers with CBCT (p < 0.001), which was not compromised by a lower specificity. Therefore, a significantly higher overall agreement was obtained with CBCT (p < 0.001). There were no significant differences between the Digora Optime phosphor plate system and the Digora Toto CMOS sensor for any parameter.
CBCT was much more accurate in the detection of surface cavitation in approximal surfaces than intraoral receptors. The differences are interpreted as clinically significant. A CBCT examination performed for other reasons should also be assessed for approximal surface cavities in teeth without restorations.
PMCID: PMC3729187
radiography; digital; computed tomography; diagnosis; dental caries
20.  Detection of Non-Cavitated Occlusal Caries with Impedance Spectroscopy and Laser Fluorescence: an In Vitro Study 
To evaluate the performance of an impedance spectroscopy technology for detecting non-cavitated occlusal caries lesions in permanent teeth in vitro. The method was compared with a commonly used laser fluorescence device and validated against histology.
Material and Methodology:
A non-cavitated sample of 100 extracted posterior teeth was randomly selected and assessed for caries on enamel and dentin level with aid of CarioScan PRO (ACIS) and DIAGNOdent pen (LF pen) by three examiners. After the measurements, the extension of the lesion was histologically determined as gold standard. Sensitivity, specificity, accuracy and receiver-operating curves were calculated. Intra- and inter-examiner reproducibility was expressed by intra class correlation coefficients.
The histological caries prevalence was 99% and 41% exhibited dentin caries. The ACIS technique displayed high specificities but almost negligible sensitivities at readings >50. A similar pattern was noted for the LF pen at readings >30. The intra- and inter-examiner reproducibility varied between 0.47 and 0.98 and the values were generally lower for the ACIS technique than for the LF pen. The inter-examiner agreement reached excellent levels with both methods.
In vitro,the ACIS technique showed a low ability to disclose occlusal caries lesions in the enamel and/or dentin of non-cavitated permanent molars. However, further in vivo studies of permanent occlusal surfaces are needed to mirror the clinical situation.
PMCID: PMC4009735  PMID: 24799965
Caries detection; impedance spectroscopy; laser fluorescence; molar teeth.
21.  Evaluating performance of dental caries detection methods among third-year dental students 
BMC Oral Health  2013;13:70.
Reliable caries detection is a cornerstone in the modern caries treatment schema. This study aimed to evaluate adopting traditional and new caries detection methods by third-year dental students.
Fifty-seven students were given lectures on caries detection, after which they evaluated 27 extracted carious teeth using traditional clinical assessment (CE), Nyvad’s, and ICDAS methods. On three teeth they also performed DIAGNOdent pen® (LF) scanning. Histological scores of the sectioned teeth (ICDAS, LF) and activity estimations of the lesions by the supervisors were used as golden standards (Nyvad, CE). For the ICDAS method , sensitivity and specificity were calculated using dentine caries (D3) as a cut-off point. Mean ICC and kappa values were calculated to evaluate interexaminer agreement for all lesions and methods. Spearman’s correlation coefficient evaluated LF scanning.
ICDAS method presented good sensitivity (0.78) and specificity (0.87). The inter-examiner agreement for different methods was fair or good (CE ICC = 0.69, κ = 0.53; Nyvad’s method ICC = 0.68, κ = 0.48, ICDAS ICC = 0.66, κ = 0.47). Variation in LF values was the greatest with lesions extending to middle third of dentin. In that case, the Spearman’s correlation coefficient was also the weakest.
To follow the guidelines by the European Core Curriculum on Cariology, the third year dental students are introduced to methods for detecting lesion depth and assessing lesion activity as well as using new caries detection methods. Their performance in estimating lesion depth is good, and fair to good in estimating lesion activity even after basic training only.
PMCID: PMC3878964  PMID: 24314305
Caries detection methods; Dental student; ICDAS
22.  Effect of changing the kilovoltage peak on radiographic caries assessment in digital and conventional radiography 
Imaging Science in Dentistry  2014;44(3):199-205.
This study aimed to investigate the effect of changing the kilovoltage peak (kVp) on the radiographic assessment of dental caries.
Materials and Methods
Seventy-five extracted posterior teeth with proximal caries or apparently sound proximal surfaces were radiographed with conventional E-speed films and a photostimulable phosphor system using 60 kVp and 70 kVp for the caries assessment. The images were evaluated by three oral radiologists and compared with the results of the stereomicroscope analysis.
No statistically significant difference was found between 60 kVp and 70 kVp for the caries detection, determination of caries extension into dentin, and caries severity in either the conventional or the digital images. Good to very good inter-observer and intra-observer agreements were found for both kilovoltage values on the conventional and digital images.
Changing the kilovoltage between 60 kVp and 70 kVp had no obvious effect on the detection of proximal caries or determination of its extension or severity.
PMCID: PMC4182354  PMID: 25279340
Diagnosis, Oral; Dental Caries; Digital Radiography, Dental; Radiography, Dental
23.  Effect of object location on the density measurement in cone-beam computed tomography versus multislice computed tomography 
Dental Research Journal  2012;9(Suppl 1):S81-S87.
Bone density measurement in a radiographic view is a valuable method for evaluating the density of bone quality before performing some dental procedures such as, dental implant placements. It seems that Cone-Beam Computed Tomography (CBCT) can be used as a diagnostic tool for evaluating the density of the bone, prior to any treatment, as the reported radiation dose in this method is minimal. The aim of this study is to investigate the effect of object location on the density measurement in CBCT versus Multislice computed tomography (CT).
Materials and Methods:
In an experimental study, three samples with similar dimensions, but different compositions, different densities (Polyethylene, Polyamide, Polyvinyl Chloride), and three bone pieces of different parts of the mandibular bone were imaged in three different positions by CBCT and Multislice CT sets. The average density value was computed for each sample in each position. Then the data obtained from each CBCT was converted to a Hounsfield unit and evaluated using a single variable T analysis. A P value <0.05 was considered to be significant.
The density in a Multislice CT is stable in the form of a Hounsfield Number, but this density is variable in the images acquired through CBCT, and the change in the position results in significant changes in the density. In this study, a statistically significant difference (P value = 0.000) has been observed for the position of the sample and its density in CBCT in comparison to Multislice CT.
Density values in CBCT are not real because they are affected by the position of the object in the machine.
PMCID: PMC3692205  PMID: 23814567
Bone density; cone-beam computed tomography; implant
24.  A comparative evaluation of cone beam CT and micro-CT on trabecular bone structures in the human mandible 
Dentomaxillofacial Radiology  2013;42(8):20130145.
The main purpose of this study was to determine the accuracy of cone beam CT (CBCT) in measuring the trabecular bone microstructure, in comparison with micro-CT. The subobjective was to examine to what extent bone quality assessment is influenced by X-ray tube current and voltage settings as well as soft tissue surrounding the bone.
Eight human mandibular bone samples were scanned using three different clinical exposure protocol within water (W1–3) and without water (NW1–3) by a high-resolution (80 µm) CBCT machine (3D Accuitomo 170®; Morita, Kyoto, Japan). Subsequently, the samples underwent micro-CT scanning (SkyScan 1174®; SkyScan, Antwerp, Belgium). After image acquisition, similar volumes of interest of the trabecular structures captured with CBCT and micro-CT were aligned with each other. Segmentation was then performed, and the morphometric parameters were quantified within the volumes of interest by CTAn software (CTAnalyser®; SkyScan, Antwerp, Belgium). Descriptive statistical analyses and multiple comparisons between all protocols were applied in R software.
High positive Pearson's correlation coefficients were observed between CBCT and micro-CT protocols for all tested morphometric indices except for trabecular thickness. No significant differences were observed between all exposure protocols except for trabecular separation. When examining the soft-tissue effect on trabecular bone structures, no significant differences between NW (1–3) and W (1–3) protocols were observed for all variables.
The present study demonstrated the potential of high-resolution CBCT imaging for in vivo applications of quantitative bone morphometry and bone quality assessment. However, the overestimation of morphometric parameters and acquisition settings in CBCT must be taken into account.
PMCID: PMC3922263  PMID: 23833320
cone beam CT; micro-computed tomography; bone architecture; quantitative bone morphometry
25.  Trabecular bone structural parameters evaluated using dental cone-beam computed tomography: cellular synthetic bones 
This study compared the adequacy of dental cone beam computed tomography (CBCT) and micro computed tomography (micro-CT) in evaluating the structural parameters of trabecular bones.
The cellular synthetic bones in 4 density groups (Groups 1–4: 0.12, 0.16, 0.20, and 0.32 g/cm3) were used in this study. Each group comprised 8 experimental specimens that were approximately 1 cm3. Dental CBCT and micro-CT scans were conducted on each specimen to obtain independent measurements of the following 4 trabecular bone structural parameters: bone volume fraction (BV/TV), specific bone surface (BS/BV), trabecular thickness (Tb.Th.), and trabecular separation (Tb.Sp.). Wilcoxon signed ranks tests were used to compare the measurement variations between the dental CBCT and micro-CT scans. A Spearman analysis was conducted to calculate the correlation coefficients (r) of the dental CBCT and micro-CT measurements.
Results and Conclusion
Of the 4 groups, the BV/TV and Tb.Th. measured using dental CBCT were larger compared with those measured using micro-CT. By contrast, the BS/BV measured using dental CBCT was significantly less compared with those measured using micro-CT. Furthermore, in the low-density groups (Groups 1 and 2), the Tb.Sp. measured using dental CBCT was smaller compared with those measured using micro-CT. However, the Tb.Sp. measured using dental CBCT was slightly larger in the high-density groups (Groups 3 and 4) than it was in the low density groups. The correlation coefficients between the BV/TV, BS/BV, Tb.Th., and Tb.Sp. values measured using dental CBCT and micro-CT were 0.9296 (p < .001), 0.8061 (p < .001), 0.9390 (p < .001), and 0.9583 (p < .001), respectively. Although the dental CBCT and micro-CT approaches exhibited high correlations, the absolute values of BV/TV, BS/BV, Tb.Th., Tb.Sp. differed significantly between these measurements. Additional studies must be conducted to evaluate using dental CBCT in clinical practice.
PMCID: PMC3826852  PMID: 24207062

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