Digital Cone-beam Computed Tomography Research Articles

A simplified low-cost phantom for image quality assessment of dental cone beam computed tomography unit.

A standardised testing protocol for evaluation of a wide range of dental cone beam computed tomography (CBCT) performance and image quality (IQ) parameters is still limited and commercially available testing tool is unaffordable by some centres. This study aims to assess the performance of a low-cost fabricated phantom for image quality assessment (IQA) of digital CBCT unit. A customised polymethyl methacrylate (PMMA) cylindrical phantom was developed for performance evaluation of Planmeca ProMax 3D Mid digital dental CBCT unit. The fabricated phantom consists of four different layers for testing specific IQ parameters such as CT number accuracy and uniformity, noise and CT number linearity. The phantom was scanned using common scanning protocols in clinical routine (90.0 kV, 8.0 mA and 13.6 s). In region-of-interest (ROI) analysis, the mean CT numbers (in Hounsfield unit, HU) and noise for water and air were determined and compared with the reference values (0 HU for water and -1000 HU for air). For linearity test, the correlation between the measured HU of different inserts with their density was studied. The average CT number were -994.1 HU and -2.4 HU, for air and water, respectively and the differences were within the recommended acceptable limit. The linearity test showed a strong positive correlation (R2 = 0.9693) between the measured HU and their densities. The fabricated IQ phantom serves as a simple and affordable testing tool for digital dental CBCT imaging.

Estimation of stature with the help of tooth length using cone beam computed tomography

Introduction and Aim: Stature is the primary tool in personal identification for forensic and physical anthropology for over a period. In the absence of full skeleton, the stature can be estimated from various skeletal components. Utilizing cranium and dentition measurements is simpler as these structures are fixed, grown and straight forward to locate. Few researches had been undertaken to establish the efficacy of teeth dimensions in height assessment. But we could not come across any such studies on tooth length. So, the present research was conducted to estimate the stature from tooth length using Cone Beam Computed Tomography (CBCT). Materials and Methods: Tooth lengths of all 4 canines were measured on digital CBCT using inbuilt software Planmeca Romexis® Software (Helsinki, Finland). Height was considered as measurement of length, from the head to toe using standard height chart. Pearson correlation test and linear regression analysis was used as a statistical tool for co-relation co-efficient and population specific formula for height assessment. Results: There was a very good correlation between tooth length and stature, with r value 0.12-0.81 and p value less than 0.05. The length of the mandibular right canine had better correlation with stature followed by mandibular left canine, maxillary left canine and maxillary right canine. Regression equation was developed from tooth length, to predict stature. Conclusion: Tooth length measuring using CBCT has a very good correlation with the height of the individual, as it is closer to actual length. Combined data, without sex as a parameter provides more accurate prediction. However, predication accuracy was better in females than males, when gender considered as a parameter in the regression analysis.

Reliability and validity of miniscrews as references in cone-beam computed tomography and intraoral scanner digital models: study on goat heads

BackgroundMiniscrews have been used to superimpose three-dimensional (3D) craniofacial images as well as explore stable structures in jaws. Our purpose was to evaluate the reliability and validity of linear and angular measurements made with miniscrews on a 3D cone-beam computed tomography (CBCT) at two voxel sizes and compared to models created by an intraoral scanner (IOS).MethodsAltogether, 64 miniscrews were placed in 12 goat jaws. The jaws were scanned by CBCT machine at 0.12 mm and 0.3 mm voxels and by the IOS. Linear and angular measurements between miniscrews on CBCT at the two voxel settings and the IOS were compared with actual measurements and with each other.ResultsAn intra-and inter-class correlation of 0.961–1.000 were obtained by each method. Linear measurements showed significant overestimations of 0.27 ± 0.24, 0.14 ± 0.22 and 0.15 ± 0.26 mm, and angular measurements showed non-significant differences of 0.11 ± 1.97°, 0.15 ± 2.79° and 0.41 ± 2.34° for the CBCT at 0.12-mm, 0.3-mm voxels and the IOS, respectively. Equal magnification of linear measurements was on homolateral and contralateral sides using CBCT, whereas significantly greater magnification on the homolateral side than on the opposite was observed using the IOS. There was no significant difference with angular measurements between digital CBCT models at two voxels and IOS. In addition, all angular measurements were comparable to actual measurement results.ConclusionsMiniscrews in CBCT and IOS are reliable and clinical valid when used as a reference measuring tooth movement. However, when miniscrews are involved in high precision measurement in CBCT or IOS image, systematic error should be taken into consideration. When comparing CBCT images, using the same voxel size is recommended for miniscrew related measurements to reduce error.

Anthropometric Dimensions of Nasopalatine Canal measured by Cone Beam Computed Tomography among Kurdish population

The purpose of this study was to find anatomical variation of nasopalatine foramen (NPF) and nasopalatine canal (NPC) in different age and gender groups among Kurdish people on cone-beam computed tomography (CBCT) images. This research included one hundred CBCT images obtained from patients visiting privet clinics with a specialty in dental and maxillofacial radiology in Sulaimani, Hawler, and Dhok governorates within a period between 2014 to 2016. Subjects were divided into three age groups (18-34, 35-49, 50-75) years old. The first group were included 15 males and 15 females, the second group 20 males and 20 females, and the third group included 15 males with 15 females. PaX i vatech digital CBCT machine was used to obtain the images by radiographers. The following measurements were estimated; number of openings of NPC at nasal fossa, mesio-lateral diameter of NPF at nasal fossa (axial section), mesio-lateral diameter of NPF at palatine fossa, anteroposterior dimension of NPC at: its upper border; middle level, and lower border, and lastly the height of NPC in sagittal section. 100 subjects (50 males and 50 females) with age range 31 years were included in this study. 69% had single NPF at the nasal fossa. 23% had two openings, and 8% had three openings. Mean and standard deviation (SD) of the mesio-lateral diameter of NPF at nasal fossa, and palatine fossa were 2.60±0.69mm, and 4.11±2.09mm respectively. NPF diameter at the palatine fossa showed significant differences between genders (P < 0.05). But age group differences did not reach the significant level (P > 0.05). The means and SD of the anteroposterior dimension of NPC were 3.46±1.53mm. There were no significant differences between genders and among age groups concerning this dimension (P > 0.05). Mean and SD of the height of NPC was 13.14±3.11mm. Males demonstrated the significantly greater length of NPC than females (P < 0.05). It is concluded that there is variation in the anatomy and morphology regarding various parameters of NPC among Kurdish population. This should be considered in mind in preoperative planning to reduce the number of complications in implant and other maxillofacial surgeries in the anterior palatine area. Also, it’s obvious that CBCT has an important role in obtaining accurate measurements of NPC different dimensions which have importance to differentiate between normal and abnormal NPC and NPF.

Anatomical variation in the dimension of nasopalatine canal on Cone Beam Computed Tomography CBCT images among sulaimani population

Objective: This study was conducted to find anatomical variation of nasopalatine canal (NPC) and nasopalatine foramen (NPF) in different age and gender groups among Sulaimani population on cone beam computed tomography (CBCT) images. Subjects and Methods: The study included one hundred CBCT images obtained from patients visiting privet clinics with specialty in dental and maxillofacial radiology in Sulaimani city extended from 2014 to 2016. Subjects were divided into three age groups (18-34, 35-49, 50-75) years old. First group included 15 males and 15 females, second group 20 males and 20 females, and the third group included 15 males with 15 females. PaX i vatech digital CBCT machine, were used to obtain the images by the radiographers. The following measurements were estimated; number of openings of NPC at nasal fossa, mesio-lateral diameter 0f NPF at nasal fossa (axial section), mesio-lateral diameter of NPF at palatine fossa, antero-posterior dimension of NPC at: its upper boarder; middle level, and lower boarder, and lastly the height of NPC in sagittal section. Results: 100 subjects (50 males and 50 females) with age range 31 year were included in this study. 69% had single NPF at the nasal fossa. 23% had two openings and 8% had three openings. Mean and standard deviation (SD) of mesio-lateral diameter of NPF at nasal fossa, and palatine fossa were 2.60±0.69 mm, and 4.11±2.09 mm respectively. NPF diameter at the palatine fossa showed significant differences between genders (P value less than 0.05). But age group differences did not reach the significant level (P value more than 0.05). The means and SD of antero-posterior dimension of NPC was 3.46±1.53 mm. There were no significant difference between genders and among age groups concerning this dimension (P value was greater than 0.05). Mean and SD of height of NPC was 13.14±3.11 mm. Males demonstrated significantly greater length of NPC than females (P value was less than 0.05). Conclusion: It is concluded that there is anatomical variation in morphology and various parameters of NPC among sulaimani population. This should be considered in preoperative planning and to reduce the number of complications in implant and other maxillofacial surgeries in anterior palatine area. CBCT has important role to obtain accurate measurements of NPC different dimensions which has importance to differentiate between normal and abnormal NPC.

Accuracy assessment of three-dimensional surface reconstructions of teeth from Cone Beam Computed Tomography scans

The use of three-dimensional (3D) models of the dentition obtained from cone beam computed tomography (CBCT) is becoming increasingly more popular in dentistry. A recent trend is to replace the traditional dental casts with digital CBCT models for diagnosis, treatment planning and simulation. The accuracy of these models was previously assessed through comparing linear physical and radiographical measurements. However, this assessment technique is both observer and landmark dependent. The accuracy of 3D CBCT teeth reconstructions is yet to be reliably measured. To assess the accuracy of 3D CBCT reconstructions of the teeth using a semi-automated and observer-independent method and to assess the influence of field of view (FoV) selection on reconstruction accuracy. Fully dentate upper and lower dry human jaws, placed in a plastic box and immersed in water, were scanned using CBCT with small, medium and large FoV. The teeth were then scanned separately using MicroCT. Cone beam computed tomography and MicroCT 3D teeth models were compared, and mean surface difference was calculated per tooth for each FoV. Mean and (maximum) differences between MicroCT and CBCT were 120 +/- 40 (max. 679) microm, 157 +/- 39 (max. 824) micro and 207 +/- 80 (max. 862) microm for the small, medium and large FoV, respectively. Cone beam computed tomography models were larger than MicroCT because of larger voxel size. Our results indicate that CBCT may provide accurate 3D reconstructions of the teeth that can be useful for some clinical applications.