Cone Beam Computed Tomography Exposure Research Articles

A Comparison between Saudi Dental Students' Knowledge of CBCT and Intraoral Radiographs: A Cross-Sectional Study

Intraoral radiography is integral to dental diagnosis while cone beam computed tomography (CBCT) provides enhanced 3D visualization. We aimed to assess and compare knowledge regarding CBCT and intraoral radiography among 386 Saudi dental undergraduates via a cross-sectional questionnaire. Nearly all participants successfully identified bitewing (99%), periapical (97%) and CBCT (98%) images, indicating strong familiarity. However, only 6% had clinically utilized CBCT versus 80% using intraoral radiography. Just 14% received CBCT training compared to 65% trained in intraoral radiography. Most appropriately recognized children as the most radiation-sensitive group (47%) and recommended limited CBCT (62%) and intraoral (37%) radiographs monthly per ALARA principles. Root canal treatment (44%) and implant planning (29%) were the most common CBCT referral indications. Key barriers to routine CBCT implementation included high costs (67%), difficulty (16%), and insufficient training (14%). Advantages perceived were reduced radiation (17%), rapid imaging (38%), and lack of film processing (24%). Results highlight excellent conceptual understanding but limited practical experience and training in CBCT compared to intraoral radiography among Saudi dental students. Targeted education programs integrating hands-on CBCT exposure with training in radiation safety and appropriate use are warranted to support optimal future clinical adoption.

Comparative evaluation of mutagenic effects of two cone-beam computed tomography in oral mucosa cells.

This pilot study aimed to evaluate the mutagenic effects in cells of the oral mucosa after exposure to two different cone beam computed tomography (CBCT). Eighteen adults were submitted to the different CBCT (Carestream CS8100 3D and I-CAT). The cells were collected immediately before the CBCT exposure and 10 days later, when the material was placed on a slide and stained using the Feulgen/Fast Green technique. Microscopic analysis counted micronuclei and other nuclear alterations, which are indicative of cytotoxicity such as pyknosis, karyolysis, karyorrhexis, and binucletion. 2000 cells were analyzed. The statistical analysis was performed with the Wilcoxon Signed-Rank test to compare the frequency of cellular alterations, and the Mann-Whitney U test to compare different CBCTs, both with a significance level of 5%. There was no statistically significant difference in the micronucleated cell count before and after the exposition to the ionizing radiation from I-CAT (p = .298) and CS8100 3D (p = .203) A significate increase of pyknosis (p < .001), karyolysis (p < .001), karyorrhexis (p < .001), and binucletion (p < .001) were noted on I-CAT CBCT. There was no statistically significant difference in cellular alterations in CS8100 3D CBCT. Despite the increase in micronuclei after exposure, this study indicates that there is no evidence of genotoxicity. On the other hand, the I-CAT CBCT produced cytotoxic effects.

Intraoperative CBCT imaging in endovascular abdomen aneurysm repair – Optimization of exposure parameters using a stent phantom

Cone beam computed tomography (CBCT) may provide essential additional image guidance to endovascular abdominal aneurysm repair (EVAR) operations but also significant radiation exposure to patients if scans are not carefully optimized. The purpose of our study was to define the image quality requirements for intraoperative EVAR CBCT imaging and to optimize the CBCT exposure parameters accordingly. A Multi-Energy CT phantom simulating a large patient was used by replacing the central phantom cylinder with a custom water-filled insert including an EVAR stent. Different exposure parameters covering a range of radiation qualities and dose levels were used to define the optimal image quality level regarding stent graft evaluation (compressed, bent, or collapsed). The radiation dose was measured with a calibrated air kerma-area product (KAP) meter and organ doses were calculated based on Monte Carlo simulations and a mathematical patient model. Based on the results, updated exposure parameters with the highest mean energy and lowest dose level available were recommended. With the updated protocol, the radiation exposure could be significantly decreased. The KAP value decreased from 9720 μGy·m2 to 440 μGy·m2 and reference point air kerma from 351 mGy to 16 mGy (a reduction of 96%) and organ doses of the organs in the irradiated region decreased on an average 91%. The new protocol resulted in acceptable clinical image quality based on testing with clinical cases.

Genotoxicity and cytotoxicity effects of x-rays on the oral mucosa epithelium at different fields of view: A cone beam computed tomography technique.

Cone beam computed tomography (CBCT) is considered a common examination for dentistry problems. Cellular biology can be affected by exposure to ionizing radiations procedures. In this study, we aimed to assess the genotoxicity and cytotoxicity effects of CBCT dental examinations at two different fields of view (FOVs) in exfoliated buccal epithelial cells. Sixty healthy adults participated in the current study. They were divided into two identical groups; CBCT with FOV of 6*6 cm2 and 8*11 cm2. Exfoliated oral mucosa cells were prepared immediately before and after 10-12 days of CBCT exposure. The cytological smears were stained with the Papanicolaou technique. The amounts of micronuclei and other cytotoxicity cellular changes (Pyknosis, Karyolysis, and Karyorrhexis) were evaluated. The variables of the parameters before and after CBCT examination in the two investigated FOVs were performed using Wilcoxon test and paired-samples t-test in SPSS software. The micronuclei and other cytotoxic changes parameters before and after CBCT exposure for both FOVs (6*6 and 8*11 cm2) increased significantly (p<0.001). Furthermore, a significant difference (p<0.05) was observed between the investigated parameters at the two FOVs. Notably, the FOV of 8*11 cm2 had more side effects than that of 6*6 cm2. There were no statistically significant among males and females for both FOVs. CBCT examinations of dental disorders would increase the risks of inducing genetic damage. The cytotoxicity and chromosomal damage were considered in males and females in both investigated FOVs (6*6 and 8*11 cm2). In this regard, the use of CBCT must be following the ALARA principle.

The usefulness of cone beam computed tomography according to age in cleft lip and palate.

The current study aimed to evaluate the usefulness of cone beam computed tomography (CBCT) examination in cleft children and adolescents, the age of the first CBCT exposure, and the criteria that justified the first CBCT exposure. A number of 229 non-syndromic cleft subjects aged between 0-22 years receiving treatment in the same specialized surgical center in orofacial cleft treatment were studied. A cleft group of 64 cleft lip and palate (CLP) children with at least one CBCT exposure was identified based on CBCT records. Parameters related to diagnosis and treatment planning in cleft deformity were considered dental anomalies and bone morphology changes. The examiners assessed whether the treatment option was necessary, not necessary, or could not be evaluated at the age of CBCT exposure. A number of thirty-nine unilateral clefts and fifteen bilateral clefts were identified. Posterior palatal cleft was present in six children (mean age: 15.03±5.55 years; male/female ratio: 1/0.8). Alveolar bone morphology changes were found in 90.58% of cases; jaw relationship changes in 71.82%; nasal fossa morphology changes in 74.99%; airway obstruction in 49.98% and maxillary asymmetry in 87.48%. Orthodontic planning was necessary for 85.93% of CLP patients, and orthognathic surgery in 39.05%. The usefulness of CBCT in patients with CLP varied with age, with reduced value for the evaluation of impaction and root resorption under the age of ten.

The Impact of Cone-Beam Computed Tomography Exposure Parameters on Peri-Implant Artifacts: A Literature Review.

Cone-beam computed tomography (CBCT) amounts to an excellent diagnostic tool to evaluate the peri-implant bone thickness in all dimensions. Despite the unquestionable advantages of CBCT, potential artifacts around dental implants might disturb the proper assessment of the surrounding structures. The artifacts may mask osseointegration, shallow bone defects, and other types of radiolucency, which make it difficult to establish an early diagnosis of bone loss. Proper diagnosis of bone defect is necessary to decide about surgical intervention. The aim of this literature review is to assess the CBCT exposure causing artifacts on the peri-implant structures. An electronic search of MEDLINE (PubMed) database includes studies published before July 2021 and supplemented by manual research. Clinical, ex vivo, in vitro, and animal studies evaluating the relationship between exposition parameters and occurrence of artifacts around the dental implant in CBCT studies were included. A literature review revealed that kilovoltage, tube current, and field of view may affect the occurrence of artifacts around dental implants, all of which would compromise radiological evaluation. Therefore, it is feasible to reduce the incidence of artifacts and improve the image quality by appropriate modification of the exposure parameters. However, the reduction of artifacts is often associated with a significant increase in radiation exposure; hence, an effort should be made to minimize the radiation dose in line with the ALARA (as low as reasonably achievable) principle.

Usefulness of an Image-Based Noise-Reduction Technique in Cone Beam Computed Tomography for Adaptive Radiotherapy

Cone-beam computed tomography (CBCT) plays an important role in adaptive radiation therapy and can be used to observe changes in body shape, tumor size, and organ position during the treatment period. This technique can also be used to generate an image for replanning. However, performing CBCT during every image guided radiotherapy (IGRT) process increases the radiation dose. Therefore, in this study, we investigated the reduction of the CBCT exposure dose using an image-based edge-preserving noise-reduction technique. A three-dimensional cross-directional bilateral filter (3D-CDBF) which was recently developed by one of the coauthors and reported to provide a noise reduction performance better than a mode-based iterative reconstruction.Catphan was used to evaluate the performance of 3D-CDBF in CBCT. The baseline scan parameters were 120 kV, 40 mA, 40 ms, and 660 frames/360° rotation. The tube current was changed to 32, 20, and 10 mA to reduce the exposure dose. The CBCT images were reconstructed with the filtered back projection (FBP). The 3D-CDBF images were obtained by processing the FBP images. Task-based spatial resolution (task-based transfer function: TTF) and noise power spectrum (NPS) were used to evaluate image quality. Visual evaluation of the image quality was also performed by two experienced radiation oncologists and five radiologists using clinical pelvic images of two patients undergoing radiotherapy for prostate cancer. Additionally, the accuracy of the dose calculation when replanning with 3D-CDBF images was evaluated.The 50%/10% TTFs were 0.364/0.646 mm-1 using FBP and 0.362/0.645 mm-1 using 3D-CDBF, suggesting the excellent edge preservation ability of 3D-CDBF. The noise power of 3D-CDBF compared to FBP were 25.4% at 0.2 mm-1 and 17.0% at 0.5 mm-1. 3D-CDBF notably reduced noise power over the entire frequency range. Therefore, the NPS level of 10 mA became similar to that of 40 mA. The visual evaluation allowed by the 3D-CDBF images was considerably higher than that realized with other images. Additionally, dose evaluation by gamma analysis showed that 3D-CDBF had no effect on the accuracy of the dose calculation.Compared with conventional FBP, the 3D-CDBF yielded significant improvements in quantitative and qualitative image qualities. The results indicated a possible 75% dose reduction of this method, while preserving the accuracy of the dose calculation.

Comparative Evaluation of Periodontal Osseous Defects Using Direct Digital Radiography and Cone-Beam Computed Tomography.

Objectives:To evaluate and compare the accuracy of Direct Digital Radiography (DDR) and cone-beam computed tomography (CBCT) in determination and diagnosis of periodontal osseous defects.Methods:A nonrandomized in vivo study was conducted to compare the two imaging modalities, DDR and CBCT, for the diagnosis of periodontal osseous defects. Comparison was made between the linear measurements of DDR and CBCT images with the actual measurements of various osseous defects during surgical exposure (Gold standard).Results:The results of the present study demonstrated the difference in the mean values of the DDR and surgical exposure measurements of periodontal osseous defects, whereas comparable mean values were found between the CBCT and surgical exposure measurements, with no statistically significant difference (P > 0.05) being found between each modality.Conclusion:CBCT proved to be an indispensable imaging tool in detecting and quantifying periodontal defects and furcation involvement more precisely and could provide additional benefits over the traditional radiography for clinical and postsurgical evaluation.

Optimisation of Varian TrueBeam head, thorax and pelvis CBCT based on patient size

AbstractPurpose:The aim of this study was to optimise patient dose and image quality of Varian TrueBeam cone beam computed tomography (CBCT) pelvis, thorax and head and neck (H&amp;N) images based on patient size.Methods:An elliptical phantom of small, medium and large size was designed representative of a local population of pelvis, thorax and H&amp;N patients. The phantom was used to establish the relationship between image noise, CT and CBCT exposure settings. Using this insight, clinical images were optimised in phases and the image quality graded qualitatively by radiographers. At each phase, the time required to match the images was recorded from the record and verify system.Results:Average patient diameter was a suitable metric to categorise patient size. Phantom measurements showed the power relationship between noise and CBCT exposure settings of value −0·15, −0·35 and −0·43 for thorax, pelvis and H&amp;N, respectively. These quantitative phantom measurements provided confidence that phased variation of ~±20% in mAs should result in clinically usable images. Qualitative assessment of almost 2000 images reduced the exposure settings in H&amp;N images by −50%, thorax images by up to −66% and pelvis images by up to −80%. These optimised CBCT settings did not affect the time required to match images.Findings:Varian TrueBeam CBCT mAs settings have been optimised for dose and image quality based on patient size for three treatment sites: pelvis, thorax and H&amp;N. Quantitative phantom measurements provided insight into the magnitude of change to implement clinically. The final optimised exposure settings were determined from radiographer qualitative image assessment.

Alteration of mucosa cell maturation pattern after exposure to different radiographic imaging methods

Aim: Dental imaging has been widely used for diagnosis in dentistry. However, dental X-ray may induce cytotoxicity leading to apoptosis in oral mucosa cells. The present study aimed to observe the maturation pattern of buccal and gingival cells after exposure to X-ray radiation from analog/digital panoramic scanning and cone beam computed tomography (CBCT). Methods: The research samples were 40 subjects who fulfilled the inclusion and exclusion criteria. The subjects were divided into the exposed (patients who received analog/digital panoramic radiography or CBCT) and controlled (patients who had no radiography examinations) groups, with 10 subjects in each group. Exfoliative cytology smears were obtained from buccal mucosa and gingiva before exposure (or on day 0 for the control group) and 10 days later. The cells were stained with the Papanicolaou method. Then, the superficial, intermediate, and parabasal cells were counted in each glass slide. Results: No significant differences (p &gt; 0.05) were observed among all cell types between day 0 and 10 in the control group. Meanwhile, after exposure to three kinds of radiography examinations, the frequency of intermediate cells in buccal mucosa and gingiva increased (p &lt; 0.05), but that of superficial cells decreased (p &lt; 0.05) significantly. No significant difference was found in the parabasal cells (p &gt; 0.05). The frequency differences between intermediate and superficial cells showed no significant difference between the buccal mucosa and gingiva. Conclusion: Analog/digital panoramic radiography and CBCT exposure can induce cytotoxicity by altering the maturation pattern of buccal mucosa cells and gingiva, so it is strongly recommended to only perform these procedures if necessary and avoid repeated exposure to the same patient.

Designing and Fabricating Nano-Structured and Micro-Structured Radiation Shields for Protection against CBCT Exposure

Researchers have always been interested in finding new and effective materials for protection against radiation. This experimental study aimed to design and fabricate new types of nano-material and micro-material based shields against the ionizing effect of cone beam computed tomography (CBCT) X-rays. To fabricate a flexible prototype, we added dioctyl phthalate (DOP) oil to emulsion polyvinyl chloride (PVC) powder. The paste was mixed and dispersed. Then, nano- and micro-powders of WO3 and Bi2O3 were added to the paste, with the weight ratio of 20% PVC, 20% DOP, and 60% nano- and micro-metals. Using an ultrasonic mixer, the polymer matrix and metals were mixed and a paste with a thick texture was developed. The resultant paste was poured into glass molds and the molds were then heated in an oven. After cooling, the resultant sheets were selected for further experiments. A CBCT unit and dosimeter were used to evaluate the characterization and X-ray shielding properties of the fabricated prototypes. The half-value layers (HVL) for nano-WO3, micro-WO3, nano-Bi2O3, and micro-Bi2O3 were 0.0390, 0.0524, 0.0351, and 0.0374 cm, respectively. In addition, the linear attenuation coefficient (µ) for these materials were 17.77, 13.20, 19.71, and 18.5 cm−1, respectively. The findings indicate that nano-structured samples are more effective in the attenuation of X-ray energy. The nano-structured WO3 prototype was nearly 34% more efficient in attenuating radiation compared to the micro-structured WO3 prototype. This difference in nano- and micro-structured Bi2O3 prototypes was 6.5%.

Do different cone beam computed tomography exposure protocols influence subjective image quality prior to and after root canal treatment?

ObjectivesThe current study aimed to evaluate different CBCT exposure protocols and influencing factors affecting the subjective image quality of scans taken for endodontic indications.Materials and methodsTwelve extracted teeth, comprising of two sets of maxillary molars, premolars, canines and incisors, mandibular premolars, and molars, were endodontically treated, and either received a fiber or metal post. The teeth were scanned by CBCT imaging before and after root canal treatment, and after post insertion. Each scan was performed thrice, using an ultra low dose (ULD), standard (SM), and high-resolution mode (HR), respectively. Twelve observers—4 endodontists, 4 periodontists, and 4 radiologists—assessed the subjective image quality using visual analogue scales (VAS). Potential influencing factors were evaluated including acquisition mode, observer specialty, stage of treatment, type of post, and type of tooth, using one-way ANOVA and T test.ResultsTeeth scanned with the ULD had the highest average VAS score (72.5), followed by HR (70.2), and SM (69.0) for values pooled from all teeth and observers. CBCT acquisition mode was not a significant influencing factor on the VAS scores. Observer specialty, stage of treatment, type of post, and type of tooth were significant influencing factors.ConclusionsBased on the present in vitro data, a low-dose CBCT mode seems not to negatively affect the perception of image quality.Clinical relevanceThe findings from this in vitro study demonstrate that a low-dose CBCT mode might have potential for diagnostics prior to or following endodontic treatment.

Detection Accuracy of Bone Defects Depending on Exposure Settings of Cone Beam Computed Tomography.

Despite the widespread use of cone beam computed tomography (CBCT), few articles have been published to assess the accuracy in detecting alveolar bone defects using different CBCT exposure settings. A human cadaver with rounded bone defects in various locations was scanned using a CBCT scanner at different settings. Four examiners twice studied 1,500 cross-sectional digital and printed slices for defect presence, location, and size. High-resolution zoom mode achieved the highest overall accuracy. Moreover, apical location of the defects significantly affected overall accuracy. Bone defect detection depends upon exposure settings of CBCT scans. Exposure settings and field of view dimensions should be individualized per case.

EFFECT OF TOOTH POSITION AND CBCT SETTINGS ON IMAGE ARTIFACT AND CONTRAST-TO-NOISE RATIO GENERATED BY 4 TYPES OF ROOT-END FILLING MATERIALS

<h3>Background</h3> After endodontic surgery, radiographic assessment is the method of choice to monitor bone defect healing. Cone beam computed tomography (CBCT) scans are useful to identify the cause of surgical intervention failure or to confirm healing; however, the artifacts generated by some root-end filling material might compromise this objective. <h3>Objective(s)</h3> The aim of this study was to compare the artifact and contrast-to-noise ratios generated by four root-end filling materials at multiple CBCT exposure settings and positions within the field of view (FOV). <h3>Study Design</h3> Twelve central incisors were endodontically treated, obturated, and then retrograde-filled using amalgam, Biodentine, SuperEBA (ethoxy benzoic acid), and mineral trioxide aggregate (MTA). A phantom was created; then, tooth samples were inserted and scanned in the center and periphery of a 4 × 4 mm field of view (FOV) using a Morita MCT-1 F8 (at multiple kV and degree acquisition settings). Image J was used to determine the artifact and contrast-to-noise generated at the same relative slice image of each tooth. <h3>Results</h3> <i>Artifacts FOV position</i>: periphery had less artifact than central (<i>P</i> value < .0001); scan setting (Degrees): 360^o had less artifact than 180^o (<i>P</i> value < .0001); tube voltage (kV): artifact decreased with increased kVp (<i>P</i> value < .0001); Materials: Biodentine was associated with less artifact compared with MTA (<i>P</i> value = .031) <i>CNR FOV position:</i> Periphery had higher contrast-to-noise ratio (CNR) than central (<i>P</i> value < .0001); scan setting (Degrees): 360^o had higher CNR compared with 180^o (<i>P</i> value <.0001); <i>Tube voltage (kV):</i> CNR increased with increased kVP (<i>P</i>-value < .0001); Materials: Amalgam was associated with lower CNR than all others (<i>P</i> value = .002) <h3>Discussion/Conclusions</h3> Biodentine, MTA, and SuperEBA are biomechanically adequate for retrograde obturation because they generated significantly less artifact compared with amalgam. The use of the 360° image slice acquisition mode generated significantly less artifact than the 180^o setting for all materials. Finally, a periphery position led to lower artifact and higher CNR compared with the central position, a finding that was contrary to previous findings in the literature.

Comparative evaluation of various methods of assessing residual alveolar ridge width prior to dental implant placement: An in vivo study

Purpose: There is always a slow but steady evolution occurred in dentistry, resulting in use of osseointegrated dental implants which became widely accepted procedure in the rehabilitation of edentulous spaces. Evaluation of the available alveolar bone dimensions is an important prerequisite for dental implant placement and successful outcome. Hence, this vivo study was designed to evaluate the accuracy of cone beam computed tomography (CBCT) and bone mapping for the diagnostic purpose.Materials and Methods: A total of 27 partially edentulous sites in maxilla and/or mandibular arch were selected according to the mentioned criteria. The width of edentulous spaces was measured and compared by three methods: CBCT, bone mapping, and surgical exposure. Later, the obtained data were sent for statistical analysis to check the accuracy of methods for the assessment of residual alveolar ridge width prior to the dental implant placements.Results: Normality check was done before finalizing statistical tests using Kolmogorov–Smirnov and Shapiro–Wilk test and non-parametric tests were applied for final analysis. Variables were compared using the Wilcoxon signed-Rank Test. Spearman's Rank correlation was obtained to check the relationship between variables. Throughout the result, significance level was fixed at 5% and if value of P < 0.05, it shows a significant result. For this study, P < 0.05 and statistically significant, which show that average measurements are significantly differ between the variables.Conclusion: CBCT and ridge mapping measurements when compared individually with the gold standard, surgical open method, CBCT proved to be a highly accurate method detecting the residual alveolar ridge width in the dental implant treatment planning.

Determination of optimum exposure parameters for dentoalveolar structures of the jaws using the CB MercuRay system with cluster signal-to-noise analysis

To determine the optimum cone beam computed tomography exposure parameters for specific diagnostic tasks. A Teflon phantom attached to a half-mandible in a large container was scanned in dental (D), implant (I), and panoramic (P) modes. An identical phantom in a small container was scanned in D mode. Both were scanned at 60, 80, 100, and 120kV. We evaluated the image quality of five anatomical structures [dentinoenamel junction (1), lamina dura and periodontal ligament space (2), trabecular pattern (3), cortex-spongy bone junction (4), and pulp chamber and root canal (5)] and analyzed the diagnostic image quality with cluster signal-to-noise analysis. We then evaluated correlations between the two image qualities and calculated the threshold of acceptable diagnostic image quality. Optimum exposure parameters were determined from images with acceptable diagnostic image quality. For the small container, the optimum exposure parameters were D mode, 80kV for (1), (3), and (4) and D mode, 100kV for (5). For the large container, they were D mode, 120kV for (1), (3), and (5) and D mode, 100kV for (4). I mode, 120kV reached the acceptable level for (4). No images reached the acceptable level for (2). No optimum exposure parameters were identified for the evaluation of the lamina dura and periodontal ligament space. D mode was sufficient for the other structures; however, the tube voltage required for each structure differed. Smaller patients required lower tube voltage. I mode, 120kV may be used for larger lesions.

Cone beam computed tomography in implant dentistry: recommendations for clinical use

BackgroundIn implant dentistry, three-dimensional (3D) imaging can be realised by dental cone beam computed tomography (CBCT), offering volumetric data on jaw bones and teeth with relatively low radiation doses and costs. The latter may explain why the market has been steadily growing since the first dental CBCT system appeared two decades ago. More than 85 different CBCT devices are currently available and this exponential growth has created a gap between scientific evidence and existing CBCT machines. Indeed, research for one CBCT machine cannot be automatically applied to other systems.MethodsSupported by a narrative review, recommendations for justified and optimized CBCT imaging in oral implant dentistry are provided.ResultsThe huge range in dose and diagnostic image quality requires further optimization and justification prior to clinical use. Yet, indications in implant dentistry may go beyond diagnostics. In fact, the inherent 3D datasets may further allow surgical planning and transfer to surgery via 3D printing or navigation. Nonetheless, effective radiation doses of distinct dental CBCT machines and protocols may largely vary with equivalent doses ranging between 2 to 200 panoramic radiographs, even for similar indications. Likewise, such variation is also noticed for diagnostic image quality, which reveals a massive variability amongst CBCT technologies and exposure protocols. For anatomical model making, the so-called segmentation accuracy may reach up to 200 μm, but considering wide variations in machine performance, larger inaccuracies may apply. This also holds true for linear measures, with accuracies of 200 μm being feasible, while sometimes fivefold inaccuracy levels may be reached. Diagnostic image quality may also be dramatically hampered by patient factors, such as motion and metal artefacts. Apart from radiodiagnostic possibilities, CBCT may offer a huge therapeutic potential, related to surgical guides and further prosthetic rehabilitation. Those additional opportunities may surely clarify part of the success of using CBCT for presurgical implant planning and its transfer to surgery and prosthetic solutions.ConclusionsHence, dental CBCT could be justified for presurgical diagnosis, preoperative planning and peroperative transfer for oral implant rehabilitation, whilst striving for optimisation of CBCT based machine-dependent, patient-specific and indication-oriented variables.

Linear accuracy of cone-beam computed tomography and a 3-dimensional facial scanning system: An anthropomorphic phantom study.

PurposeThis study was conducted to evaluate the accuracy of linear measurements of 3-dimensional (3D) images generated by cone-beam computed tomography (CBCT) and facial scanning systems, and to assess the effect of scanning parameters, such as CBCT exposure settings, on image quality.Materials and MethodsCBCT and facial scanning images of an anthropomorphic phantom showing 13 soft-tissue anatomical landmarks were used in the study. The distances between the anatomical landmarks on the phantom were measured to obtain a reference for evaluating the accuracy of the 3D facial soft-tissue images. The distances between the 3D image landmarks were measured using a 3D distance measurement tool. The effect of scanning parameters on CBCT image quality was evaluated by visually comparing images acquired under different exposure conditions, but at a constant threshold.ResultsComparison of the repeated direct phantom and image-based measurements revealed good reproducibility. There were no significant differences between the direct phantom and image-based measurements of the CBCT surface volume-rendered images. Five of the 15 measurements of the 3D facial scans were found to be significantly different from their corresponding direct phantom measurements (P<.05). The quality of the CBCT surface volume-rendered images acquired at a constant threshold varied across different exposure conditions.ConclusionThese results proved that existing 3D imaging techniques were satisfactorily accurate for clinical applications, and that optimizing the variables that affected image quality, such as the exposure parameters, was critical for image acquisition.

The role of BMP-2, low-level laser therapy and low x-ray doses in dental follicle stem cell migration

ABSTRACTThe knowledge of how cells respond to different treatments in terms of their migration potential could improve bone regeneration and osseointegration of dental implants. The objective of this study was to elucidate the effects of various chemoattractants, bone morphogenetic protein-2 (BMP-2), low-level laser therapy (LLLT), and cone beam computed tomography (CBCT) on the migration of dental follicle stem cells (DFSCs). The chemoattractants used in our study were the serum-free (SF) conditioned media that were harvested from osteoblast cell cultures seeded on the surface of titanium implants—Ti6Al7Nb (TiCtrl), implants infiltrated with hydroxyapatite (TiHA), with silicatitanate (TiSiO2), and from culture of DFSCs cultivated on TiCtrl implants. We used the scratch migration assay to evaluate the influence of BMP-2, LLLT therapy, and CBCT on the migration potential of DFSCs. The migration scratch assay indicates that the BMP-2 growth factor is able to increase the DFSC migration compared to control culturing medium and regardless of laser or CBCT exposure. The results demonstrate the importance of improving the implant surface with HA, SiO2, and DFSCs. Stimulated DFSCs will secrete growth factors which will act as chemoattractants for the stem cells of the implant host. Adding growth factors such as BMP-2 can improve the migration process of DFSCs.

Accuracy of segmentation of tooth structures using 3 different CBCT machines

The aim of this study was to evaluate the volumetric accuracy and reliability of cone beam computed tomography (CBCT)-based tooth segmentation using 4 different CBCT exposure protocols. Two dry, intact adult human mandibles of unknown gender were scanned using 4 different CBCT exposure protocols (3 CBCT systems). The available mandibular premolars (3 per mandible) were segmented, resulting in a total of 24segmented teeth. To assess the accuracy of the segmented teeth, volumetric and morphologic differences between the real anatomic teeth and the reconstructed images were evaluated both physically and using a high-resolution micro-computed tomography system. Results revealed a high accuracy of CBCT reconstructed images when comparing volumetric measures of CBCT-based segmented premolars to physical measurements of corresponding physical teeth. Volumetric differences were below 2%. Morphologic differences using the segmented model and the corresponding micro-computed tomography scans of the physical teeth indicated that when inaccuracies occurred, they were at the apical and coronal parts of the tooth. Based on these results, CBCT can be used as a tool for segmentation and pretherapeutic planning procedures.