Search

Objective To qualitatively and quantitatively assess integrated segmentation of three convolutional neural network (CNN) models for the creation of a maxillary virtual patient (MVP) from cone-beam computed tomography (CBCT) images. Materials and methods A dataset of 40 CBCT scans acquired with different scanning parameters was selected. Three previously validated individual CNN models were integrated to achieve a combined segmentation of maxillary complex, maxillary sinuses, and upper dentition. Two experts performed a qualitative assessment, scoring-integrated segmentations from 0 to 10 based on the number of required refinements. Furthermore, experts executed refinements, allowing performance comparison between integrated automated segmentation (AS) and refined segmentation (RS) models. Inter-observer consistency of the refinements and the time needed to create a full-resolution automatic segmentation were calculated. Results From the dataset, 85% scored 7–10, and 15% were within 3–6. The average time required for automated segmentation was 1.7 min. Performance metrics indicated an excellent overlap between automatic and refined segmentation with a dice similarity coefficient (DSC) of 99.3%. High inter-observer consistency of refinements was observed, with a 95% Hausdorff distance (HD) of 0.045 mm. Conclusion The integrated CNN models proved to be fast, accurate, and consistent along with a strong interobserver consistency in creating the MVP. Clinical relevance The automated segmentation of these structures simultaneously could act as a valuable tool in clinical orthodontics, implant rehabilitation, and any oral or maxillofacial surgical procedures, where visualization of MVP and its relationship with surrounding structures is a necessity for reaching an accurate diagnosis and patient-specific treatment planning.

The objective of this review was to assess the accuracy of available means of determining the BBT (buccal bone thickness) and/or BBL (buccal bone level). This was translated into the following research question: What is the accuracy of the available means of visualizing the BBP (buccal bone plate) to establish the BBT and/or the BBL, when compared to control measurements? As control measurements histomorphometric measurements, direct measurements and cone-beam computed tomography (CBCT) measurements in the absence of metal are accepted.METHODS: The literary search was performed by searching the databases of MEDLINE, Embase, and Web of Science, up to July 13, 2021. Types of studies included were clinical, in vitro and animal trials, specifically looking into the bone level and/or bone thickness of the buccal bone plate at oral implants. Reference lists were hand searched for relevant articles. Two reviewers performed the data extraction and analysis. Only studies using reliable control measurements to evaluate the accuracy of the tested means of visualizing BBT and/or BBL were included for analysis. The QUADAS-2 tool was used to perform bias analysis on the relevant studies. Extracted data was tabulated to show the differences between test and control measurements for BBT and BBL. For in vitro studies on CBCT measurements of BBT meta-analysis could be performed.A total of 1176 papers were identified in the search. Twenty-two articles were used for data extraction and qualitative analysis. Of these studies nine were animal studies, 9 were in vitro studies and four were human studies. Six animal studies and three human studies provided data on probing. CBCT and sonography as techniques for visualizing the buccal bone plate. Probing at implant sites seems to provide data that correlates with a consistent distance from the BBP. Meta-analysis for probing studies could not be performed due to heterogeneity in the setups of these studies. Eleven studies on CBCT were eligible for inclusion. Of these three were animal studies, the remaining 8 studies were all in vitro studies. Meta-analysis was performed on the accuracy of CBCT for in vitro studies, finding a significant underestimation of the BBT when compared to control measurements by a mean difference of -0.15 mm with 95%CI [-0.26,-0.03]. Three studies were identified on measurement of BBT and/or BBL by sonography. This included one human study and two in vitro studies. The identified studies show a low error when determining the buccal bone level or thickness using sonography. All included studies possess a high risk of bias according to risk of bias analysis, mostly due to selection of the patient.A strong limitation of this systematic review is the inclusion of different studies with heterogeneous designs. Within the limits of this analysis it cannot be concluded that probing is an accurate way of visualizing the BBP. CBCT cannot yet be recommended as a standard diagnostic tool for follow-up of the BBP at oral implants. The application of sonography as a diagnostic tool to visualize the BBP needs further scientific validation.

Objective: To present patient dose levels for different CBCT scanners, acquired by a dose monitoring tool in a University Hospital, as a function of field of view (FOV), operation mode, and patient age. Methods: An integrated dose monitoring tool was used to collect radiation exposure data [type of CBCT unit, dose-area product (DAP), FOV size, and operation mode] and patient demographic information (age, referral department) performed on a 3D Accuitomo 170 and a Newtom VGI EVO unit. Effective dose conversion factors were calculated and implemented into the dose monitoring system. For each CBCT unit, the frequency of examinations, clinical indications, and effective dose levels were obtained for different age and FOV groups, and operation modes. Results: A total of 5163 CBCT examinations were analyzed. Surgical planning and follow-up were the most frequent clinical indications. For the standard operation mode, effective doses ranged from 35.1 to 300 µSv and 9.26-117 µSv using 3D Accuitomo 170 and Newtom VGI EVO, respectively. In general, effective doses decreased with increasing age and FOV size reduction. Conclusions: Effective dose levels varied notably between systems and operation modes.Operation mode selection and FOV size were indication-oriented, with larger FOV sizes election serving surgical planning and follow-up. Seeing the influence of FOV size on effective dose levels, manufacturers could be advised to move toward patient-specific collimation and dynamic FOV selection. Systematically monitoring patient doses could be recommended for steering future CBCT optimization.

OBJECTIVE: The objectives of this study were to assess observers' preference for standard screens (SSs) or medical displays (MDs) in visualizing difficult-to-diagnose radiographic dental abnormalities and their preference for dental filter tools when utilized with MD systems. STUDY DESIGN: A retrospective data set of 60 in vivo radiographs consisting of intraoral (n = 20), panoramic (n = 20), and cone beam computed tomography (n = 20) images was created. Three image display monitors, including an SS, an MD, and an MD with 3 dental filter configurations (bone-low density enhancement filter, tooth-high density enhancement filter, and a combined filter representing regular MD), were utilized to assess 4 observers' monitor preferences in detecting radiographically subtle dental abnormalities. The data were analyzed by using binomial distribution. A P value ≤.05 was considered statistically significant. RESULTS: Although observers expressed preference for MD for visualizing some abnormalities when examining intraoral and panoramic radiographs, MD was not preferred for detection of any abnormalities with cone beam computed tomography. There were no significant differences in preference for SS or MD overall (P ≥ .2024). Observers expressed significant preference for the filters in visualizing all but 2 abnormalities (P ≤ .0252). CONCLUSIONS: The use of MD monitors enabled with dental filter tools may be preferred for visualizing certain subtle abnormalities. ispartof: ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY ORAL RADIOLOGY vol:132 issue:4 pages:475-482 ispartof: location:United States status: published

OBJECTIVES: This study aimed to describe and compare CBCT imaging prescription in clinical practice among orthodontists from five countries in Europe and America. Additionally, it investigated factors associated with the prescribing and the use of guidelines for CBCT imaging. MATERIALS AND METHODS: A cross-sectional survey was carried out using an online questionnaire sent to all registered orthodontists in Belgium, Brazil, Canada, Romania, and the United States of America (USA). The data were analyzed by descriptive statistics, bivariate tests, and Poisson regression. RESULTS: The final sample consisted of 1284 participants. CBCT was prescribed by 84.4% of the participants for selected cases (84.9%), mainly for impacted teeth (92.4%), presurgical planning (54.1%), and root resorption (51.9%). High cost was most frequently the limiting factor for CBCT prescription (55.4%). Only 45.2% of those who were using CBCT imaging reported adhering to guidelines. CBCT imaging prescription was associated with the orthodontists’ countries (p < .009, except for Belgium, p = .068), while the use of guidelines was associated with the respondents’ country and additional training on CBCT imaging (p < .001). CONCLUSIONS: Orthodontists refer patients for CBCT for selected indications (impacted teeth, root resorption, presurgical planning, dentofacial deformities, as suggested by the international guidelines, and also for upper airway and temporomandibular joint evaluation). Many do not adhere to specific guidelines. There are substantial variations between the countries about the orthodontists’ referral for CBCT and guideline usage, irrespective of gender. CBCT prescription may be limited by financial barriers, adhering to specific guidelines and prior CBCT training. CLINICAL RELEVANCE: CBCT prescription among orthodontists must be based on prescription criteria and current guidelines. It is advised to improve CBCT education and training to enhance CBCT selection, referral, analysis, and interpretation in orthodontic practice.

AIM To evaluate 3D accuracy and outcome of a dynamic navigation method for guided root canal treatment of severe pulp canal obliteration (PCO) in 3D printed jaws. METHODOLOGY Three operators with different levels of experience in Endodontics performed navigated access cavities, using the Navident system (ClaroNav), in two sets (maxillary and mandibular) of 3D-printed jaw models with teeth presenting severe PCO. Models were mounted on a phantom to mimic a real clinical situation. After treatment, a postoperative high resolution Cone-Beam Computer Tomography (CBCT) scan (NewTom) was taken for each model and registered to the preoperative model. All access cavities were then segmented using 3-Matic Medical software 15.0 (Materialise). Length and volume of each access cavity were measured, and a comparison was done by measuring the distance deviation in mm at the coronal entry point, apical point, vertical deviation, total deviation and angular deviation of the access cavity in comparison with the virtual planning. Additionally, all access cavities were scouted with a size 10 K-file and inspected on the CBCT to confirm that the canal was located. Descriptive statistics for each parameter were performed. Normality of the data was assessed; data were transformed if needed to make it normally distributed. One-way analysis of variance (anova) was applied to assess differences between parameters for tooth type, jaw, and operators and corrected for simultaneous hypothesis testing according to Tukey. Significance level was set at .05. RESULTS After training with the system (28 cavities per operator), a total of 132 teeth and 168 access cavities (56 per operator) were prepared. All operators located a total of 156 canals, obtaining an overall success of 93% without a difference between operator experience (p > .05). The mean deviation at the apical point was 0.63 mm (SD 0.35) and was significantly lower in anterior teeth in comparison with molars (p

OBJECTIVE: The aim of this study was to propose and validate a three-dimensional (3D) methodology for the assessment of canine eruption in patients born with unilateral cleft lip and palate (UCLP) following secondary alveolar bone graft (SABG). METHODS AND MATERIALS: A total of 10 patients (four females, six males; mean age: 8.8 years) with UCLP who underwent SABG were recruited. Pre- and 6-month post-operative cone-beam computed tomography (CBCT) was acquired for all patients. Post-operative data was registered onto pre-operative data utilizing voxel-based registration. Following superimposition, a segmentation process was applied to segment maxillary canine on both cleft and non-cleft side. Thereafter, translational and rotational changes in canine position were assessed for both cleft and non-cleft side by two observers. RESULTS: The intra-class correlation coefficient (ICC) indicated excellent reliability (≥0.90) with inter and intra-observer error of less than 0.05 mm. The overall ICC was found to be high for assessing both translational and rotational changes. The mean absolute inter- and intra-observer difference for translational and rotational changes was found to be less than 1 mm and 3°. CONCLUSION: The present method was found to be reliable proving to be clinically applicable for assessing maxillary canine eruption changes in both cleft and non-cleft bone. ispartof: CLINICAL AND EXPERIMENTAL DENTAL RESEARCH vol:7 issue:3 pages:285-292 ispartof: location:United States status: published

The purpose of this study was to validate the applicability of using maxillary voxel-based dentoalveolar registration (VDAR) at long-term follow up in orthognathic surgical patients. A retrospective sample of 25 patients (skeletal class II or III) who underwent bimaxillary orthognathic surgery was recruited and divided into two groups. Group A included 15 patients (seven females, eight males, mean (SD) age 25.8 (14.4) years) with unrestored dentition and group B involved 10 patients (five females, five males, mean (SD) age: 26.2 (11.9) years) with dental restorative treatment. Postoperative cone-beam computed tomography (CBCT) scans were acquired at four time-points, one to six weeks (T1), six months (T2), one year (T3) and two years (T4). Voxel- based registration was applied using the cranial base and then complete dental segment with part of the alveolar bone at T1-T2, T1-T3 and T1-T4 time-intervals. The translational and rotational accuracy and reproducibility of the registered maxillary segment was evaluated at these three intervals by analysing the transformation matrix using singular value decomposition. All translational and rotational measurements showed excellent reliability in both groups without any significant difference. The combined translational and rotational difference was found to be within the clinically acceptable range of 2mm and 4°. The VDAR was found to be accurate and reliable to be utilised for a long-term skeletal follow-up in orthognathic surgical patients.

Being able to correctly interpret radiographs after a traumatic dental injury is an essential skill for providing appropriate and timely treatment. The aim of this study was to assess the impact of case complexity on paediatric dentists' performance when radiographically diagnosing traumatic dental injuries (TDI) and to investigate a possible added value of cone-beam computed tomography (CBCT) when compared with digital intra-oral radiography (2D vs 3D).A test panel of paediatric dentists was instructed to detect, identify and interpret radiographic findings using either 2D or 3D images. Intra-oral radiographs and CBCT images of 20 trauma cases were presented in random order, and the findings were recorded using structured scoring sheets. Case complexity was determined by two experienced benchmark scorers. Results were analysed using generalized linear mixed modelling.In general, performance for detection, identification and interpretation of findings was low, both with 2D and 3D images, with significantly lower values for difficult cases (p 0.05). For easy as well as for difficult cases, 3D imaging resulted in a significantly better performance for detection and identification of findings (P 0.001). This was not the case for correct interpretation, where significantly poorer performance was seen when using 3D images for difficult cases (p 0.05).This study provides evidence that case complexity of traumatic dental injuries influences diagnostic performance. The use of CBCT enhanced detection and identification of findings but when case complexity increased, 3D imaging adversely affected correct interpretation.

Objectives: To investigate the dose-area product (DAP) of cone-beam computed tomography (CBCT) examinations for different scan settings and imaging indications, and to establish institutional diagnostic reference levels (DRLs) for dose optimisation. Methods: A retrospective analysis of the DAP values of 3568 CBCT examinations taken from two different devices at the Prince Philip Dental Hospital, Hong Kong between 2016 and 2021 was performed. Patient- (age, gender, and imaging indication) and imaging-related (CBCT device, field-of-view (FOV), and voxel size) were correlated with the DAPs. The indication-oriented third-quartile DAP values were compared with DRLs from the UK, Finland, and Switzerland. The obtained third-quartile DAPs lower than the national DRLs and those for which no national DRLs have been proposed were used to establish institutional DRLs. Results: In the investigated CBCTs, the DAP value for large FOV scans was significantly lower than medium/small FOVs. CBCTs with a small voxel size exhibited a significantly higher DAP than those with a medium/large voxel size. CBCTs for endodontic, periodontal, orthodontic, or orthognathic evaluation exhibited a significantly higher DAP than other indications. Twelve indication-oriented institutional DRLs were established and five of them were lower than the national DRLs: third molars (229 mGy×cm2), jaw cysts/tumours (410 mGy×cm2), maxillary sinus pathology (520 mGy×cm2), developing dentition (164 mGy×cm2), and periapical lesions (564 mGy×cm2). Conclusions: CBCT examinations for endodontic, periodontal, orthodontic, or orthognathic evaluation may deliver a higher radiation dose to the patient than other imaging tasks. A periodic review of the patient dose from CBCT imaging and establishment of institutional DRLs for specific clinical settings are needed for monitoring patient dose and to optimise indication-oriented scanning protocols.

OBJECTIVES: The overall objective of this study was to assess how metal artefacts impact image quality of 13 CBCT devices. As a secondary objective, the influence of scanning protocols and field of view on CBCT image quality with and without metal artefacts was also assessed.MATERIALS AND METHODS: CBCT images were acquired of a dry human skull phantom considering three clinical simulated conditions: one without metal and two with metallic materials (metallic pin and implant). An industrial micro-CT was used as a reference to register the CBCT images. Afterwards, four observers evaluated 306 representative image slices from 13 devices, ranking them from best to worst. Furthermore, within each device, medium FOV and small FOV standard images were compared. General linear mixed models were used to assess subjective perception of examiners on overall image quality in the absence and presence of metal-related artefacts (p RESULTS: Image quality perception significantly differed amongst CBCT devices (p CONCLUSIONS: Subjective image quality differs significantly amongst CBCT devices and scanning protocols. Metal-related artefacts may highly impact image quality, with a significant device-dependent variability and only few scanners being more robust against metal artefacts. Often, metal artefact expression may be somewhat reduced by proper protocol selection.CLINICAL RELEVANCE: Metallic objects may severely impact image quality in several CBCT devices.

Guided endodontics has been used for the treatment of anterior teeth with a successful outcome. This approach is not only limited to anterior teeth because it can also be used for the treatment of premolars and molars. However, in such cases, space may be a limitation because a long bur has to be used in addition to the guide being placed on top of the teeth. The aim of this case report was to present a novel guided endodontics technique using a sleeveless 3-dimensional-printed guide. This design can reduce vertical space, allowing an open view of the tooth and irrigation during drilling. A 46-year-old female patient consulted the endodontic department with intermittent pain around tooth #5. Tooth #5 presented pain upon percussion and responded negative to a cold test. The initial periapical radiograph revealed an apical radiolucency with pulp canal obliteration. Clinically, there was no sinus tract. The tooth was diagnosed with pulp necrosis and symptomatic apical periodontitis. Guided endodontic treatment was performed with a sleeveless 3-dimensional-printed guide and long neck carbide bur with a head diameter of 1 mm to drill a minimally invasive access cavity up to the root canal. A completely healed apical area of tooth #5 was visible after 1 year on periapical radiographs. This technique seems to be a promising alternative in comparison with the conventional guided endodontic guide design for the negotiation of pulp canal obliteration in cases in which vertical space is limited.

OBJECTIVE: The aim of this study was to assess observers' preference for a dentomaxillofacial dedicated medical display (MD) vs a general-purpose standard screen (SS) for in vitro and in vivo observation of normal radioanatomic features. STUDY DESIGN: The in vitro sample consisted of 2-dimensional (2-D) intraoral (n = 15), panoramic (n = 2), cephalometric (n = 2), and 3-dimensional (3-D) cone beam computed tomography (CBCT) (n = 9) data sets, acquired by utilizing commercially available skull and head-and-neck phantoms. The in vivo sample consisted of 80 radiographs (intraoral = 20; panoramic = 20; cephalometric = 20; and CBCT = 20). In vitro and in vivo data sets were both acquired by using Minray, Promax2-D, and Vistapano Ceph for 2-D images and Accuitomo, NewTom VGi evo, and Promax3-D for CBCT images. Five observers entered screen preferences when evaluating the appearance of radioanatomic structures on MD and SS. RESULTS: Both in vitro and in vivo assessments showed good interobserver and excellent intraobserver agreement. In vitro data suggested a significant preference for MD over SS for viewing radioanatomic features on panoramic and CBCT images, whereas MD was significantly preferred for in vivo images of all imaging modalities (P < .001). CONCLUSIONS: Overall, observers preferred MD over SS for both in vitro and in vivo observation of normal radioanatomic features irrespective of the imaging modality. ispartof: ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY ORAL RADIOLOGY vol:130 issue:2 pages:217-224 ispartof: location:United States status: published

The purpose of this study was to assess the accuracy of 2-dimensional morphometric parameters of root canals on different cone-beam computed tomographic (CBCT) images using 2 segmentation methods (operator dependent and Otsu's automatic), considering micro-computed tomographic (micro-CT) images as the reference standard.Ten mandibular molars were scanned by micro-CT imaging and 3 different CBCT devices: Accuitomo (J Morita Corporation, Kyoto, Japan), NewTom 5G (CEFLA, Imola, Italy), and NewTom VGi evo (CEFLA). The images were standardized and recorded using MeVisLab software (MeVis Medical Solutions AG, Bremen, Germany). Two calibrated examiners assessed the images of axial reconstructions quantitatively by 2-dimensional parameters (area, perimeter, roundness, and largest and smallest diameter). Fleiss kappa was performed to check interrater and intrarater reliability. The absolute error was calculated as the means and standard deviation. One-way analysis of variance was performed for comparison between the methods used by the operator and Otsu's automatic thresholding. To determine the accuracy of CBCT devices, the absolute error rate of each parameter was calculated using micro-CT measurements as the reference value with thresholding determined by the operator.The thresholding method performed by the operator had lower absolute error values for area, perimeter, and major and minor diameters, differing (P.05) from Otsu's automatic method, with no differences between the CBCT machines.An overestimation of area, roundness, and major and minor diameters and an underestimation of the perimeter were shown for the 3 CBCT machines evaluated. Thresholding determined by the operator is more accurate than that determined by Otsu's automatic method for the assessment of 2-dimensional morphometric parameters, which could direct influence in the diagnosis and endodontic treatment plan.

Lack of evidence exists related to the three-dimensional (3D) pharyngeal airway space (PAS) changes at follow-up after isolated bilateral sagittal split osteotomy (BSSO) advancement surgery. The present study assessed the 3D PAS changes following isolated mandibular advancement at a follow-up period of 1 year. A total of 120 patients (40 males, 80 females, mean age: 26.0 ± 12.2) who underwent BSSO advancement surgery were recruited. Cone-beam computed tomography (CBCT) scans were acquired preoperatively (T0), immediately following surgery (T1), and at 1 year of follow-up (T2). The volume, surface area, and minimal cross-sectional area (mCSA) of the airway were assessed. The total airway showed a 38% increase in volume and 13% increase in surface area from T0 to T1, where the oropharyngeal region showed the maximum immediate change. At T1−T2 follow-up, both volumetric and surface area showed a relapse of less than 7% for all sub-regions. The mCSA showed a significant increase of 71% from T0 to T1 (p < 0.0001), whereas a non-significant relapse was observed at T1−T2 (p = 0.1252). The PAS remained stable at a follow-up period of 1 year. In conclusion, BSSO advancement surgery could be regarded as a stable procedure for widening of the PAS with maintenance of positive space at follow-up. ispartof: JOURNAL OF IMAGING vol:8 issue:4 ispartof: location:Switzerland status: published

Made available in DSpace on 2022-04-28T19:51:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-04-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Objectives: To assess the influence of dental fillings on the performance of an artificial intelligence (AI)-driven tool for tooth segmentation on cone-beam computed tomography (CBCT) according to the type of tooth. Methods: A total of 175 CBCT scans (500 teeth) were recruited for performing training (140 CBCT scans - 400 teeth) and validation (35 CBCT scans - 100 teeth) of the AI convolutional neural networks. The test dataset involved 74 CBCT scans (226 teeth), which was further divided into control and experimental groups depending on the presence of dental filling: without filling (control group: 24 CBCT scans – 113 teeth) and with coronal and/or root filling (experimental group: 50 CBCT scans – 113 teeth). The segmentation performance for both groups was assessed. Additionally, 10% of each tooth type (anterior, premolar, and molar) was randomly selected for time analysis according to manual, AI-based and refined-AI segmentation methods. Results: The presence of fillings significantly influenced the segmentation performance (p

The present study investigated the accuracy, consistency, and time-efficiency of a novel deep convolutional neural network (CNN) based model for the automated maxillofacial bone segmentation from cone beam computed tomography (CBCT) images.A dataset of 144 scans was acquired from two CBCT devices and randomly divided into three subsets: training set (n = 110), validation set (n = 10) and testing set (n = 24). A three-dimensional (3D) U-Net (CNN) model was developed, and the achieved automated segmentation was compared with a manual approach.The average time required for automated segmentation was 39.1 s with a 204-fold decrease in time consumption compared to manual segmentation (132.7 min). The model was highly accurate for identification of the bony structures of the anatomical region of interest with a dice similarity coefficient (DSC) of 92.6%. Additionally, the fully deterministic nature of the CNN model was able to provide 100% consistency without any variability. The inter-observer consistency for expert-based minor correction of the automated segmentation observed an excellent DSC of 99.7%.The proposed CNN model provided a time-efficient, accurate, and consistent CBCT-based automated segmentation of the maxillofacial complex.Automated segmentation of the maxillofacial complex could act as an alternative to the conventional segmentation techniques for improving the efficiency of the digital workflows. This approach could deliver accurate and ready-to-print3D models, essential to patient-specific digital treatment planning for orthodontics, maxillofacial surgery, and implant dentistry.

Background The aim of this study is to evaluate the impact of experience with traumatic dental injuries (TDI) on paediatric dentists’ performance and self-assessed confidence when radiodiagnosing traumatic dental injuries (TDI) and to explore whether this is influenced by the imaging technique used (2D versus 3D). Materials and methods Both 2D and 3D radiological images of young anterior permanent teeth having experienced dental trauma were assessed randomly by a panel of paediatric dentists using structured scoring sheets. The impact of level of experience with dental traumatology on radiological detection, identification and interpretation of lesions and on observer’s self-assessed confidence was evaluated. Findings were compared to benchmark data deriving from expert consensus of an experienced paediatric endodontologist and dentomaxillofacial radiologist. Results were analysed using generalized linear mixed modelling. Results Overall, observers performed moderately to poor, irrespective of their level of TDI experience and imaging modality used. No proof could be yielded that paediatric dentists with high TDI experience performed better than those with low experience, for any of the outcomes and irrespective of the imaging modality used. When comparing the use of 3D images with 2D images, significantly higher sensitivities for the detection and correct identification of anomalies were observed in the low experienced group (P P Conclusion There was no proof that paediatric dentist’s higher experience with TDI is associated with better radiodiagnostic performance. Neither could it be proven that the use of Cone Beam Computed Tomography (CBCT) contributes to an improved interpretation of findings, for any experience level. More experienced dentists feel more confident, irrespective of the imaging modality used, but this does not correlate with improved performance. The overall poor performance in image interpretation highlights the importance of teaching and training in both dental radiology and dental traumatology.

OBJECTIVE: Three-dimensional (3D) quantitative assessment of external root resorption (ERR) following combined orthodontic-orthognathic surgical treatment is vital for ensuring an optimal long-term tooth prognosis. In this era, lack of evidence exists applying automated 3D approaches for assessing ERR. Therefore, this study aimed to validate a protocol for 3D quantification of ERR on cone-beam computed tomography (CBCT) images following combined orthodontic-orthognathic surgical treatment. MATERIAL AND METHODS: Twenty patients who underwent combined orthodontic-orthognathic surgical treatment were recruited. Each patient had CBCT scans acquired with NewTom VGi evo (NewTom) at three time-points i.e., 4-weeks prior to surgery (T0), 1-week (T1) and 1-year after surgery (T2). Patients were divided into two groups, group A (surgical Le Fort I osteotomy group: 10 patients) and group B (orthodontic group without maxillary surgical intervention: 10 patients). Root resorption was assessed by measuring length and volumetric changes of maxillary premolar to premolar teeth (central and lateral incisors, canines, 1st and 2nd premolars= 10 teeth) at T0-T1 and T0-T2 time intervals in both groups. The protocol consisted of convolutional neural network based segmentation followed by surface-based superimposition and automated 3D analysis. RESULTS: The intra-observer intra-class correlation coefficient (ICC) was found to be excellent (1.0) with an average error of 0 mm and 0 mm3 for assessing root length and volume, respectively. The entire protocol took 56.8 ± 7 s for quantifying ERR. Both group of patients showed negligible changes in length and volumetric ratio at T0-T1 time-interval. Furthermore, group A had lower ERR ratio with decreased root volume and length compared to group B at T0-T2 time-interval. CONCLUSIONS: The proposed protocol was found to be time efficient, accurate and reliable for 3D quantification of ERR on CBCT images. It could act as a viable automated option for assessing ERR. CLINICAL SIGNIFICANCE: The automated protocol could provide a time efficient method to allow a reliable and accurate 3D follow up root resorption after orthognathic and orthodontic treatment procedures. These new insights could allow clinicians to implement strategies for minimizing the risk of root resorption and to further enhance treatment predictability. ispartof: JOURNAL OF STOMATOLOGY ORAL AND MAXILLOFACIAL SURGERY vol:124 issue:1 ispartof: location:France status: published

The dental practice has largely evolved in the last 50 years following a better understanding of the biomechanical behaviour of teeth and its supporting structures, as well as developments in the fields of imaging and biomaterials. However, many patients still encounter treatment failures; this is related to the complex nature of evaluating the biomechanical aspects of each clinical situation due to the numerous patient-specific parameters, such as occlusion and root anatomy. In parallel, the advent of cone beam computed tomography enabled researchers in the field of odontology as well as clinicians to gather and model patient data with sufficient accuracy using image processing and finite element technologies. These developments gave rise to a new precision medicine concept that proposes to individually assess anatomical and biomechanical characteristics and adapt treatment options accordingly. While this approach is already applied in maxillofacial surgery, its implementation in dentistry is still restricted. However, recent advancements in artificial intelligence make it possible to automate several parts of the laborious modelling task, bringing such user-assisted decision-support tools closer to both clinicians and researchers. Therefore, the present narrative review aimed to present and discuss the current literature investigating patient-specific modelling in dentistry, its state-of-the-art applications, and research perspectives.

Objective The aim of the study was to propose and validate a method for three-dimensional (3D) quantitative assessment of secondary alveolar bone grafting (SABG) and its stability in time for patients with unilateral cleft lip and palate (UCLP). Settings and sample population 10 non-syndromic UCLP patients (9 males and 1 female with a mean age of 9.5±0.9 years) undergoing SABG with good quality preoperative, immediate postoperative (6 weeks) and 6 months postoperative Cone Beam Computed Tomography (CBCT) scans were selected. Materials and methods The preoperative and 6 months postoperative scans were registered onto the immediate postoperative scan. The bone grafted region was defined on the immediate postoperative scan and refined on the registered preoperative scan resulting in a 3D volume. The residual bone graft was calculated by applying threshold based segmentation on the registered 6 months postoperative scan within the segmented bone graft volume of the previous step. Inter and intra observer tests using intra-class correlation coefficient (ICC) were applied comparing the volumes of the 3D models. Results An excellent reliability was found for inter and intra observers with ICC ≥ 0.95. Conclusions The presented method proved to be reliable for volumetric assessment of the alveolar bone graft in UCLP patients as well as to assess the percentage of bone resorption during follow-up.

To assess the accuracy of a novel Artificial Intelligence (AI)-driven tool for automated detection of teeth and small edentulous regions on Cone-Beam Computed Tomography (CBCT) images.After AI training and testing with 175 CBCT scans (130 for training and 40 for testing), validation was performed on a total of 46 CBCT scans selected for this purpose. Scans were split into fully dentate and partially dentate patients (small edentulous regions). The AI Driven tool (Virtual Patient Creator, Relu BV, Leuven, Belgium) automatically detected, segmented and labelled teeth and edentulous regions. Human performance served as clinical reference. Accuracy and speed of the AI-driven tool to detect and label teeth and edentulous regions in partially edentulous jaws were assessed. Automatic tooth segmentation was compared to manually refined segmentation and accuracy by means of Intersetion over Union (IoU) and 95% Hausdorff Distance served as a secondary outcome.The AI-driven tool achieved a general accuracy of 99.7% and 99% for detection and labelling of teeth and missing teeth for both fully dentate and partially dentate patients, respectively. Automated detections took a median time of 1.5s, while the human operator median time was 98s (P0.0001). Segmentation accuracy measured by Intersection over Union was 0.96 and 0.97 for fully dentate and partially edentulous jaws respectively.The AI-driven tool was accurate and fast for CBCT-based detection, segmentation and labelling of teeth and missing teeth in partial edentulism.The use of AI may represent a promising time-saving tool serving radiological reporting, with a major step forward towards automated dental charting, as well as surgical and treatment planning.

An accurate three-dimensional (3D) segmentation of the maxillary sinus is crucial for multiple diagnostic and treatment applications. Yet, it is challenging and time-consuming when manually performed on a cone-beam computed tomography (CBCT) dataset. Recently, convolutional neural networks (CNNs) have proven to provide excellent performance in the field of 3D image analysis. Hence, this study developed and validated a novel automated CNN-based methodology for the segmentation of maxillary sinus using CBCT images. A dataset of 264 sinuses were acquired from 2 CBCT devices and randomly divided into 3 subsets: training, validation, and testing. A 3D U-Net architecture CNN model was developed and compared to semi-automatic segmentation in terms of time, accuracy, and consistency. The average time was significantly reduced (p-value

The digital workflow process follows different steps for all dental specialties. However, the main ingredient for the diagnosis, treatment planning and follow-up workflow recipes is the imaging chain. The steps in the imaging chain usually include all or at least some of the following modalities: cone-beam computed tomographic data acquisition, segmentation of the cone-beam computed tomography image, intraoral scanning, facial three-dimensional soft tissue capture and superimposition of all the images for the creation of a virtual augmented model. As a relevant clinical problem, the accumulation of error at each step of the chain might negatively influence the final outcome. For an efficient digital workflow, it is important to be aware of the existing challenges within the imaging chain. Furthermore, artificial intelligence-based strategies need to be integrated in the future to make the workflow more simplified, accurate and efficient. ispartof: DENTOMAXILLOFACIAL RADIOLOGY vol:50 issue:7 ispartof: location:England status: published

BACKGROUND/AIM: There is a lack of evidence regarding the radiological characteristics of a periapical radiolucency (PRL) fusion with the nasopalatine canal (NPC) following dentoalveolar trauma. The aim of this study was to assess the NPC enlargement resulting from fusion with a PRL and its relationship with the surrounding anatomical structures. MATERIAL AND METHODS: A total of 100 patients was retrospectively recruited and divided into two groups: case group and control group. The case group consisted of 50 cone-beam computed tomography scans of the maxilla of patients (32 males, 18 females; age range: 11-83 years) with a known history of dentoalveolar trauma in the maxillary anterior region and the presence of an undiagnosed and/or asymptomatic NPC and PRL fusion. An age- and gender-matched control group of 50 patients (32 males, 18 females; age range: 11-82 years) without trauma history to the upper anterior teeth, demonstrating normal maxillary scans, was recruited. A subjective scoring criterion was established for assessing the characteristics of the fused lesion and its relationship with the buccal/palatal alveolar cortex, nasal cavity cortex, NPC cortical border, and maxillary sinus floor. RESULTS: The fused NPC and PRL was mainly lobular in appearance (88%) with non-corticated well-defined margins (80%). Male patients showed larger (68%) dimensions compared with female patients (32%). The NPC cortical bone was the most commonly perforated structure in relation to fusion (72%), whereas maxillary sinus cortical bone was the least effected (2%). A statistically significant difference was observed between the NPC dimensions in the control and test groups, with fused lesions having larger mesiolateral, craniocaudal, and buccopalatal dimensions (P < .001). CONCLUSIONS: Periapical radiolucencies should be treated as soon as possible before they fuse with NPC. In case of fusion, surgical enucleation should be considered as the treatment of choice. ispartof: DENTAL TRAUMATOLOGY vol:36 issue:4 pages:438-445 ispartof: location:Denmark status: published

Orthognathic surgery involving the mandible can lead to remodelling of the temporomandibular joint (TMJ). Cone beam computed tomography (CBCT) provides an easily accessible three-dimensional (3D) approach to study this entity. A systematic review of the literature was performed with the aim of identifying condylar remodelling analysis protocols using CBCT-derived 3D models. The search yielded 10 eligible studies. The systematic review identified three pillars of a condylar remodelling analysis protocol that were retrievable from each of the included studies: (1) registration, (2) segmentation, and (3) analysis. The studies lacked consensus on how these pillars should be transferred to their respective protocol. Through critical assessment, criteria for a universal condylar remodelling analysis are suggested: (1) performance of a regional voxel-based registration of baseline and postoperative CBCT scans using an anatomical region not prone to postoperative changes, (2) application of a (semi-)automated 3D segmentation algorithm, (3) performance of a combination of both volumetric and surface-based 3D condylar analysis, and (4) extensive validation of each step of the protocol. The homogenization of condylar remodelling analysis protocols and their incorporation into virtual planning software suites raises the potential for the inclusion of larger numbers of patients in future prospective studies in order to gain evidence-based data. ispartof: INTERNATIONAL JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY vol:49 issue:2 pages:207-217 ispartof: location:Denmark status: published

To verify whether mandibular cortical analyses accurately distinguish postmenopausal women with normal bone mineral density (BMD) from women with osteoporosis by means of a cone-beam computed tomography (CBCT)–driven composite osteoporosis index (three-dimensional mandibular osteoporosis index—3D MOI). The comparison was performed between 52 women with normal BMD and 51 women with osteoporosis according to dual-energy X-ray absorptiometry (DXA) examination of the lumbar spine and hip. Mandibular cortical width (MCW) and cortical quality were evaluated on cross-sectional and panoramic reconstructed images. ANOVA, ROC curves and accuracy measurements were used for statistical analyses, as well as a predictive model combining the quantitative and qualitative analyses and age. All CBCT-driven measurements presented good to moderate intra- and interobserver agreements. MCW values were significantly lower in women with osteoporosis. Postmenopausal women with osteoporosis were 8 times more likely to have the cortex classified as C3, and 2.4 times more likely to have MCW thinner than 2.75 mm. The area under the ROC curve was 0.8 for the predictive model. The newly developed 3D MOI enables distinguishing women with osteoporosis from those with normal BMD with good sensitivity and specificity. Whenever a CBCT scan is performed for specific clinical indications, a 3D MOI may be performed to qualitatively and quantitatively assess the condition of the mandibular cortex. This may be surely helpful to assess the osteoporosis status in the ageing population and more specifically in peri- or postmenopausal women.

OBJECTIVE To investigate the relationship between preoperative trabecular bone structure and implant outcome based on bone morphometric bone parameters from CBCT scans. MATERIALS AND METHODS Twenty consecutive cases with early implant failure in the posterior region of the mandible were matched with 20 control patients with a successful implant osseointegration selected. All patients had taken a preoperative CBCT image according to a standardized acquisition protocol. On these CBCT scans, the trabecular bone of each implantation site was selected and segmented, after which 3D morphometric bone parameters were calculated and used in a cluster analysis to objectively differentiate trabecular bone patterns. Fisher's exact test was used to determine whether there is a significant association between trabecular pattern and implant outcome. RESULTS A sparse, intermediate, and dense trabecular bone pattern was distinguished by cluster analysis. The relationship between the trabecular bone pattern and early implant failure was significant (z = 9.6; p

To provide an indication-based and scanner-specific radiation dose and risk guide for paediatric patients undergoing dental and maxillofacial cone beam computed tomography (CBCT) examinations. Five commercially available scanners were simulated in EGSnrc Monte Carlo (MC) code. Dedicated, in-house built, head and neck voxel models, each consisting of 22 segmented organs, were used in the study. Organ doses and life attributable risk (LAR) for cancer incidence were assessed for males and females, aged 5 to 14 years old, for every clinically available protocol: central upper and lower incisors, upper and lower premolars, upper and lower jaws, cleft palate, temporal bone, sinus, dentomaxillofacial complex, and face and skull imaging. Dose results were normalised to the x-ray tube load (mAs) and logarithmic curves were fit to organ dose and risk versus age data. Females demonstrated higher LAR values in all cases. A well-established dose decreasing pattern with increasing age-at-exposure was observed. Central upper incisor protocols were those with the lowest risk, contrary to skull protocols which provided the highest LAR values. Salivary glands and oral mucosa were the highest irradiated organs in all cases, followed by extrathoracic tissue (ET) in protocols where the entire nasal cavity was inside the primary field. The dose to thyroid was considerably high for younger patients. This work provides an extensive dose assessment guide for 5 dental CBCTs, enabling detailed dose assessment for every paediatric patient. • Radiation dose concerns due to the growing use of paediatric dental and maxillofacial CBCT underline the need for justification that should in part be based on radiation exposure in radiology. • Patient-specific dose calculations based on Monte Carlo simulations and head-neck paediatric voxel models overcome the limitations of conventional thermoluminescent dosimeter (TLD) dosimetry and provide proper guidance for justification of CBCT exposures. • Monte Carlo simulations with head-neck models reveal an organ dose and radiation risk decreasing pattern with increasing age at exposure, and with decreasing size of the scanning volume of interest (field of view).

A narrative review on the potential use of low-dose protocols for cone beam computed tomography (CBCT) was conducted to identify indications and their relevance for various dental disciplines. Google Scholar was searched using the words “low-dose CBCT”. Reviews, consensus papers, clinical studies, and experimental studies were eligible for the initial screening process, but for data extraction only original articles were selected. Similar search procedures were then performed with the additional search words “pedo,” “ortho,” “endo,” “implant,” “perio,” and “oral surgery.” Furthermore, references of included articles were examined to identify further relevant articles. After screening, 27 publications remained for the data extraction process. Low-dose protocols have been reported for specialties such as pediatric dentistry (evaluating orofacial clefts, periapical lesions, impacted teeth, and autotransplantation), orthodontics (cephalometric analysis and interim assessment of treatment results), endodontics (detecting root fractures, resorptions and periapical bone loss), implant dentistry (planning implant insertion, evaluating peri-implant fenestration and dehiscence), periodontology (assessing periodontal structures), and oral and maxillofacial surgery (assessing mandibular third molars and TMJs). Nevertheless, most of the literature available is related to non-clinical studies. Furthermore, there is a lack of position statements or guidelines from authoritative bodies regarding the use of low-dose protocols in dental medicine. Low-dose protocols for CBCT imaging seem to have potential in various disciplines in dental medicine ranging from pediatric dentistry to oral and maxillofacial surgery. Dose reduction is usually achieved by mAs reduction, use of partial rotations, reduced number of projections, and larger voxel sizes, but seldom by kV reduction. Albeit low-dose protocols have potential to result in a reduction of dose exposure for 3D imaging due to dental indications, there is a need to more clearly specify indications and limitations to avoid indiscriminate use of standard and high-dose CBCT scans in the future on the lines of ALARA/ALADA principles.

Objectives Automatic tooth segmentation and classification from cone beam computed tomography (CBCT) have become an integral component of the digital dental workflows. Therefore, the aim of this study was to develop and validate a deep learning approach for an automatic tooth segmentation and classification from CBCT images. Methods A dataset of 186 CBCT scans was acquired from two CBCT machines with different acquisition settings. An artificial intelligence (AI) framework was built to segment and classify teeth. Teeth were segmented in a three-step approach with each step consisting of a 3D U-Net and step 2 included classification. The dataset was divided into training set (140 scans) to train the model based on ground-truth segmented teeth, validation set (35 scans) to test the model performance and test set (11 scans) to evaluate the model performance compared to ground-truth. Different evaluation metrics were used such as precision, recall rate and time. Results The AI framework correctly segmented teeth with optimal precision (0.98±0.02) and recall (0.83±0.05). The difference between the AI model and ground-truth was 0.56±0.38 mm based on 95% Hausdorff distance confirming the high performance of AI compared to ground-truth. Furthermore, segmentation of all the teeth within a scan was more than 1800 times faster for AI compared to that of an expert. Teeth classification also performed optimally with a recall rate of 98.5% and precision of 97.9%. Conclusions The proposed 3D U-Net based AI framework is an accurate and time-efficient deep learning system for automatic tooth segmentation and classification without expert refinement. Clinical significance The proposed system might enable potential future applications for diagnostics and treatment planning in the field of digital dentistry, while reducing clinical workload.

OBJECTIVES: The planning accuracy and stability during follow-up of segmented Le Fort I osteotomy, often evaluated using 2D cephalometry and dental cast analysis, is controversial. The aim of this study is to develop and validate a 3D semi-automatic, voxel-based registration assessment protocol to evaluate planning accuracy and stability of segmented Le Fort I osteotomy with individualization of the maxillary segments. METHODS: Preoperative, immediate postoperative and six months postoperative CBCT images were used to evaluate accuracy and stability of the individual segments in 20 patients (13 female; 7 male) who underwent segmented Le Fort I osteotomy. Three translational (left/right, intrusion/extrusion, anterior/posterior) and three rotational (pitch, roll, yaw) dimensions were calculated for each maxillary segment by means of a user-friendly module. Inter- and intra-observer Inter Class Coefficient (ICC) and mean absolute difference (MAD) were calculated. RESULTS: The inter- and intra-observer reliability ICC varied between 0.93 and 0.99 for the translational and rotational accuracy and stability assessments, indicating excellent reliability. The MAD ranged between 0.21 mm and 0.32 mm for the translational error and between 0.6° and 0.9° for the rotational dimension. CONCLUSIONS: The 3D assessment protocol for accuracy of segmented Le Fort I planning and short-term follow-up, proved to have high reliability with only a small margin of error. CLINICAL SIGNIFICANCE: The proposed 3D assessment protocol allows future in-depth analysis of segmented Le Fort I osteotomy and might implicate future improvement where necessary. ispartof: JOURNAL OF DENTISTRY vol:111 ispartof: location:England status: published

Background The purpose of this study was to objectively assess dimensional alteration (blooming artefact) on dental implant using 13 cone-beam computed tomography (CBCT) devices adjusted to device-specific scanning protocols and to assess whether subjective adjustment of brightness and contrast (B&C) could alter its visualization. Methods An anthropomorphic phantom containing a dental implant was scanned in 13 CBCT devices adjusted to three scanning protocols: medium-FOV standard resolution, small-FOV standard resolution, and small-FOV high resolution. The diameter of the implant was measured at five levels, averaged, and compared with those from a reference standard industrial CT image. B&C adjustments were performed and measurements were repeated. The intraclass correlation coefficient assessed the reliability of the measurements and general linear mixed models were applied for multiples comparisons at a 95% confidence interval. Results Implant diameter obtained from small-FOV high-resolution protocols in most CBCT devices was not significantly different when compared to that from the reference (p > 0.05). For standard protocols, significant dimensional alteration of the implant ranging from 23 to 34% (0.67 to 1.02 mm) was observed in 9 CBCT devices for small-FOV scanning (p < 0.05), and in 8 CBCT devices for medium-FOV scanning, implant dimensional alteration ranged significantly from 21 to 35% (0.62 to 1.04 mm). After B&C adjustments, dimensional alteration was reduced for several of the CBCT devices tested (p < 0.05). Conclusions The visualization of the implant dimensional alteration differed between CBCT devices and scanning protocols with an increase in diameter ranging from 0.27 to 1.04 mm. For most CBCT devices, B&C adjustments allowed to reduce visualization of implant blooming.

Objectives: The purpose of this study was to estimate the radiation dose for a dental spectral cone-beam CT (SCBCT) unit at different scanning parameters. Methods: Radiation dose measurements were performed for a commercially available dental SCBCT. Scans were obtained at different exposure times and fields of view (FOV), both for non-spectral (25×18 cm, 14×18 cm, 14×12 cm, 9×9 cm, 6×6 cm) and spectral modes (14×18 cm, 14×12 cm, 9×9 cm, 6×6 cm) with the tube voltage alternating between 80 and 110 kV for spectral mode, and fixed at 110 kV for non-spectral mode. An ion chamber was used for air kerma and dose area product (DAP) measurements. The effective dose was estimated based on the mAs using previously published logarithmic curves for CBCT units with a similar X-ray spectrum. Results: The adult effective dose, in non-spectral mode, was 44-269 µSv for small FOVs, 131-336 µSv for the medium FOV, and 163-476 µSv for the large FOV. In spectral mode, the estimated adult effective doses were 96-206 µSv for small, 299 µSv for medium and 372 µSv for large FOV protocols. Paediatric effective doses were estimated to be 75% higher than corresponding adult doses. Conclusion: SCBCT showed comparable doses with other CBCT devices, but DAP values were generally above currently published DRLs. Spectral imaging might allow for artefact reduction at comparable dose levels, which should be assessed in further image quality studies at both a technical and diagnostic levels.

Made available in DSpace on 2021-06-25T15:06:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-06-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Fundacao de Apoio a Pesquisa do Distrito Federal European Union Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie grant Aarhus University Research Foundation (AIAS-COFUND) Introduction: The purpose of this study was to classify 10 cone-beam computed tomographic (CBCT) devices using a ranking model according to the detection of fine endodontic structures. Methods: A dedicated dentate anthropomorphic phantom was scanned 2 times using 10 CBCT devices without any metal (metal-free condition) and with an endodontically treated tooth containing a metallic post (metal condition). A reference image acquired on an industrial micro-CT scanner was used to register all CBCT images, yielding corresponding anatomic slices. Afterward, 3 experienced observers assessed all acquired CBCT images for their ability to assess a narrow canal, isthmus, and apical delta ramification using a categoric rank from 1 (best) to 10 (worst). Fleiss kappa statistics were used to calculate intra-and interobserver agreements for each CBCT device separately. Based on the observers' scores, general linear mixed models were applied to compare image quality among different CBCT devices for performing endodontic diagnostic tasks (a 5 .05). Results: The 10 CBCT devices performed differently for the evaluated endodontic tasks (P , .05), with 3 devices performing better for endodontic feature detection. Yet, in the presence of metal, only 2 devices were able to keep a high level of endodontic feature detection. Conclusions: The evaluated endodontic tasks were CBCT device dependent, and their detection was influenced by the presence of metal. (J Endod 2021;47:947-953.) Sao Paulo State Univ, Sch Dent, Dept Restorat Dent, Araraquara, SP, Brazil Katholieke Univ Leuven, OMFS IMPATH Res Grp, Dept Imaging & Pathol, Fac Med, Leuven, Belgium Univ Hosp Leuven, Oral & Maxillofacial Surg, Leuven, Belgium Univ Estadual Campinas, Piracicaba Dent Sch, Div Oral Radiol, Dept Oral Diag, Piracicaba, SP, Brazil Univ Brasilia, Dept Dent, Fac Hlth Sci, Brasilia, DF, Brazil Aarhus Univ, Aarhus Inst Adv Studies, Aarhus, Denmark Katholieke Univ Leuven, Dept Mech Engn, Leuven, Belgium Karolinska Inst, Dept Dent Med, Stockholm, Sweden Sao Paulo State Univ, Sch Dent, Dept Restorat Dent, Araraquara, SP, Brazil CAPES: 001 FAPESP: 2019/22885-0 Fundacao de Apoio a Pesquisa do Distrito Federal: 23106.013588/2019-5 European Union Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie grant: 754513

OBJECTIVES: To describe the relationship between maxillary sinus (MS) and upper teeth based on cone beam computed tomographic scans (CBCT). MATERIALS AND METHODS: Based on CBCT maxillary imaging data of 147 patients, distance between MS and apices of canines and posterior maxillary teeth were assessed. Distances between tooth roots and sinus were classified into three groups: distant (>2 mm), close (

OBJECTIVES: This study aimed to identify potential clinical and radiological predictors associated with the outcome of discectomies. METHODS: In this retrospective observational study, the material comprised preoperative CBCT images and medical records of 62 patients with disc derangement disorders, who had undergone discectomy because of disc displacement with reduction (DDwR), disc displacement without reduction (DDwoR), systemic arthritis (SA), or joint hypermobility. Clinical and radiographic variables were analysed in relation to success rate determined by subjective, objective and combined outcomes. RESULTS: The success odds ratio was 11 times higher in patients with painful DDwR versus that of SA (p = 0.03), and even 25.9 times higher when considering solely objective outcome (p = 0.03). In the absence of subchondral pseudocyst, there were 5.2 times higher odds to have a successful subjective outcome (p = 0.04). Extensive bone apposition on the temporal joint component indicated a 9.3 times higher likelihood of a failed objective outcome (p = 0.04). CONCLUSIONS: There is a significant higher risk for combined outcome failure for the diagnosis SA involving the TMJ compared with DDwR. Predictors of importance based on CBCT findings related to the objective outcome failure were extensive bone apposition on the temporal joint component and condylar subchondral pseudocysts for the subjective outcome failure. ispartof: ORAL DISEASES vol:28 issue:8 pages:2185-2193 ispartof: location:Denmark status: published

The aim of this study was to quantify the symmetry of the facial hard tissue structures using three-dimensional radiographic imaging modalities in a normal Caucasian population group.Electronic literature search was conducted in the following databases: PubMed, Embase, Web of Science, and Cochrane Library up to February 2021. The studies assessing symmetry of facial bones using computed tomography (CT) and cone beam CT were included.The initial search revealed 8811 studies. Full-text analysis was performed on 33 studies. Only 10 studies were found eligible based on the inclusion criteria. The qualitative analysis revealed that a significant variability existed in relation to the methodologies applied for symmetry quantification.The current review suggested that the overall relative symmetry of the normal Caucasian population group varied depending on the skeletal structure being assessed; however, majority of the observations showed a symmetry within the range of 1 mm without any significant difference between left and right sides.The quantification of facial hard tissue structure symmetry is vital for the diagnosis and treatment planning of orthodontic and/or maxillofacial surgical procedures. Prospero registration number CRD42020169908.

INTRODUCTION: Tooth segmentation on cone-beam computed tomographic (CBCT) imaging is a labor-intensive task considering the limited contrast resolution and potential disturbance by various artifacts. Fully automated tooth segmentation cannot be achieved by merely relying on CBCT intensity variations. This study aimed to develop and validate an artificial intelligence (AI)-driven tool for automated tooth segmentation on CBCT imaging. METHODS: A total of 433 Digital Imaging and Communications in Medicine images of single- and double-rooted teeth randomly selected from 314 anonymized CBCT scans were imported and manually segmented. An AI-driven tooth segmentation algorithm based on a feature pyramid network was developed to automatically detect and segment teeth, replacing manual user contour placement. The AI-driven tool was evaluated based on volume comparison, intersection over union, the Dice score coefficient, morphologic surface deviation, and total segmentation time. RESULTS: Overall, AI-driven and clinical reference segmentations resulted in very similar segmentation volumes. The mean intersection over union for full-tooth segmentation was 0.87 (±0.03) and 0.88 (±0.03) for semiautomated (SA) (clinical reference) versus fully automated AI-driven (F-AI) and refined AI-driven (R-AI) tooth segmentation, respectively. R-AI and F-AI segmentation showed an average median surface deviation from SA segmentation of 9.96 μm (±59.33 μm) and 7.85 μm (±69.55 μm), respectively. SA segmentations of single- and double-rooted teeth had a mean total time of 6.6 minutes (±76.15 seconds), F-AI segmentation of 0.5 minutes (±8.64 seconds, 12 times faster), and R-AI segmentation of 1.2 minutes (±33.02 seconds, 6 times faster). CONCLUSIONS: This study showed a unique fast and accurate approach for AI-driven automated tooth segmentation on CBCT imaging. These results may open doors for AI-driven applications in surgical and treatment planning in oral health care. ispartof: JOURNAL OF ENDODONTICS vol:47 issue:5 pages:827-835 ispartof: location:United States status: published

Automatic craniomaxillofacial (CMF) three dimensional (3D) dense phenotyping promises quantification of the complete CMF shape compared to the limiting use of sparse landmarks in classical phenotyping. This study assesses the accuracy and reliability of this new approach on the human mandible. Classic and automatic phenotyping techniques were applied on 30 unaltered and 20 operated human mandibles. Seven observers indicated 26 anatomical landmarks on each mandible three times. All mandibles were subjected to three rounds of automatic phenotyping using Meshmonk. The toolbox performed non-rigid surface registration of a template mandibular mesh consisting of 17,415 quasi landmarks on each target mandible and the quasi landmarks corresponding to the 26 anatomical locations of interest were identified. Repeated-measures reliability was assessed using root mean square (RMS) distances of repeated landmark indications to their centroid. Automatic phenotyping showed very low RMS distances confirming excellent repeated-measures reliability. The average Euclidean distance between manual and corresponding automatic landmarks was 1.40 mm for the unaltered and 1.76 mm for the operated sample. Centroid sizes from the automatic and manual shape configurations were highly similar with intraclass correlation coefficients (ICC) of > 0.99. Reproducibility coefficients for centroid size were 0.90 indicating again high similarity between shapes quantified by classic or automatic phenotyping. Combined, these findings established high accuracy and repeated-measures reliability of the automatic approach. 3D dense CMF phenotyping of the human mandible using the Meshmonk toolbox introduces a novel improvement in quantifying CMF shape. Automatic craniomaxillofacial (CMF) three dimensional (3D) dense phenotyping promises quantification of the complete CMF shape compared to the limiting use of sparse landmarks in classical phenotyping. This study assesses the accuracy and reliability of this new approach on the human mandible. Classic and automatic phenotyping techniques were applied on 30 unaltered and 20 operated human mandibles. Seven observers indicated 26 anatomical landmarks on each mandible three times. All mandibles were subjected to three rounds of automatic phenotyping using Meshmonk. The toolbox performed non-rigid surface registration of a template mandibular mesh consisting of 17,415 quasi landmarks on each target mandible and the quasi landmarks corresponding to the 26 anatomical locations of interest were identified. Repeated-measures reliability was assessed using root mean square (RMS) distances of repeated landmark indications to their centroid. Automatic phenotyping showed very low RMS distances confirming excellent repeated-measures reliability. The average Euclidean distance between manual and corresponding automatic landmarks was 1.40 mm for the unaltered and 1.76 mm for the operated sample. Centroid sizes from the automatic and manual shape configurations were highly similar with intraclass correlation coefficients (ICC) of > 0.99. Reproducibility coefficients for centroid size were 0.90 indicating again high similarity between shapes quantified by classic or automatic phenotyping. Combined, these findings established high accuracy and repeated-measures reliability of the automatic approach. 3D dense CMF phenotyping of the human mandible using the Meshmonk toolbox introduces a novel improvement in quantifying CMF shape. ispartof: Scientific Reports vol:11 issue:1 ispartof: location:England status: published

OBJECTIVES: This study proposed and investigated the performance of a deep learning based three-dimensional (3D) convolutional neural network (CNN) model for automatic segmentation of the pharyngeal airway space (PAS). METHODS: A dataset of 103 computed tomography (CT) and cone-beam CT (CBCT) scans was acquired from an orthognathic surgery patients database. The acquisition devices consisted of 1 CT (128-slice multi-slice spiral CT, Siemens Somatom Definition Flash, Siemens AG, Erlangen, Germany) and 2 CBCT devices (Promax 3D Max, Planmeca, Helsinki, Finland and Newtom VGi evo, Cefla, Imola, Italy) with different scanning parameters. A 3D CNN-based model (3D U-Net) was built for automatic segmentation of the PAS. The complete CT/CBCT dataset was split into three sets, training set (n = 48) for training the model based on the ground-truth observer-based manual segmentation, test set (n = 25) for getting the final performance of the model and validation set (n = 30) for evaluating the model's performance versus observer-based segmentation. RESULTS: The CNN model was able to identify the segmented region with optimal precision (0.97±0.01) and recall (0.96±0.03). The maximal difference between the automatic segmentation and ground truth based on 95% hausdorff distance score was 0.98±0.74mm. The dice score of 0.97±0.02 confirmed the high similarity of the segmented region to the ground truth. The Intersection over union (IoU) metric was also found to be high (0.93±0.03). Based on the acquisition devices, Newtom VGi evo CBCT showed improved performance compared to the Promax 3D Max and CT device. CONCLUSION: The proposed 3D U-Net model offered an accurate and time-efficient method for the segmentation of PAS from CT/CBCT images. CLINICAL SIGNIFICANCE: The proposed method can allow clinicians to accurately and efficiently diagnose, plan treatment and follow-up patients with dento-skeletal deformities and obstructive sleep apnea which might influence the upper airway space, thereby further improving patient care. ispartof: JOURNAL OF DENTISTRY vol:111 ispartof: location:England status: published

Background Early detection of marginal bone loss is vital for treatment planning and prognosis of teeth and implant. This study was conducted to assess diagnostic accuracy of CBCT compared to intra-oral (IO) radiography for detection, classification, and measurement of peri-implant bone defects in an animal model. Methods Fifty-four mandible blocks with implants were harvested from nine male health adult beagle dogs with acquisition of IO, CBCT and micro-CT images from all samples. Peri-implant bone defects from 16 samples were diagnosed using micro-CT and classified into 3 defect categories: dehiscence (n = 5), infrabony defect (n = 3) and crater-like defect (n = 8). Following training and calibration of the observers, they asked to detect location (mesial, distal, buccal, lingual) and shape of the defect (dehiscence, horizontal defect, vertical defect, carter-like defect) utilizing both IO and CBCT images. Both observers assessed defect depth and width on IO, CBCT and micro-CT images at each side of peri-implant bone defect via CT-analyzer software. Data were analyzed using SPSS software and a p value of Results Overall, there was a high diagnostic accuracy for detection of bone defects with CBCT images (sensitivity: 100%/100%), while IO images showed a reduction in accuracy (sensitivity: 69%/63%). Similarly, diagnostic accuracy for defect classification was significantly higher for CBCT, whereas IO images were unable to correctly identify vestibular dehiscence, with incorrect assessment of half of the infrabony defects. For accuracy of measuring defect depth and width, a higher correlation was observed between CBCT and gold standard micro-CT (r = 0.91, 95% CI 0.86–0.94), whereas a lower correlation was seen for IO images (r = 0.82, 95% CI 0.67–0.91). Conclusions The diagnostic accuracy and reliability of CBCT was found to be superior to IO imaging for the detection, classification, and measurement of peri-implant bone defects. The application of CBCT adds substantial information related to the peri-implant bone defect diagnosis and decision-making which cannot be achieved with conventional IO imaging.

Objective: This article aims to appraise how scientific evidence related to CBCT has changed over the years, based on levels of evidence and diagnostic efficacy. Methods: A general search strategy was used in different databases (Pubmed, Embase, and Web of Science) to identify systematic reviews (SRs) on CBCT until November of 2020. The SRs included were divided according to different specialties of dentistry. A critical review of the articles was made, describing the level of evidence and efficacy. Results: In total, 75 articles were selected. There was an increase in the number of SRs on CBCT from 2014 onwards, as 83% of the SRs on this topic were published after 2013, and 72% between 2016 and to date. Twenty SRs (27%) performed meta-analysis. Only 28% of the SRs provided a detailed description of CBCT protocols. According to SR evidence, almost all specialties of dentistry have advanced concomitantly with the introduction of CBCT. The majority of SRs were related to clinical applications (level 2 of efficacy), followed by technical parameters (level 1 of efficacy). Only some CBCT models were mentioned in the SRs selected. Conclusion: Over the course of 20 years, SRs related to CBCT applications for a broad range of dental specialties have been published, with the vast majority of studies at levels 1 and 2 of diagnostic efficacy. Not all CBCT models available on the market have been scientifically validated. At all times, one should remain cautious as such not to simply extrapolate in vitro results to the clinical setting. Also, considering the wide variety of CBCT devices and protocols, reported results should not be overstated or generalized, as outcomes often refer to specific CBCT devices and protocols.

Objectives:To evaluate the influence of artefacts in cone beam CT (CBCT) images of filled root canals in isthmus-containing molars.Methods:10 teeth presenting canals with an isthmus were instrumented and filled with a thermoplasticised obturation technique. The teeth were scanned using a micro-CT device and two CBCT devices: 3D Accuitomo 170 (ACC) and NewTom VGi evo (NT), with different acquisition protocols: larger and smaller voxel size. Three examiners assessed the CBCT images for: (1) detection of filling voids; (2) assessment of under- or overestimation of the filling material and (3) resemblance of CBCT images to the reference standard. Analyses of Task 1 yielded accuracy, sensitivity and specificity for detection of filling voids. For tasks 2 and 3, statistical analysis was performed using Wilcoxon test. The level of significance was set at p < .05.Results:For Task 1, ACC showed higher sensitivity, whereas NT presented higher specificity. No significant difference was found between the protocols in ACC, however, for NT, differences between protocols were significant for all diagnostic values. In Task 2, visualisation of the filling was overestimated for NT, while for ACC, underestimation was observed. For Task 3, images with smaller voxel size were more similar to the reference image, for both CBCT devices.Conclusions:Different artefacts compromise the detection of filling voids on CBCT images of canals in mandibular molars with isthmus. ACC and NT present rather similar diagnostic accuracy, even though artefact expression remains device-specific.

Patient movement affects image quality in oral and maxillofacial cone-beam computed tomography imaging. While many efforts are made to minimize the possibility of motion during a scan, relatively little attention has been given to motion correction after acquisition. We propose a novel method which can improve the image quality after an oral and maxillofacial scan. The proposed method is based on our previous work and is a retrospective motion estimation and motion compensation (ME/MC) approach that iteratively estimates and compensates for rigid pose change over time. During motion estimation, image update and motion update are performed alternately in a multi-resolution scheme to obtain the motion. We propose use of a feature-based motion update and patch-based image update in the iterative estimation process, to alleviate the effect of limited scan field of view on estimation. During motion compensation, a fine-resolution image reconstruction was performed with compensation for the estimated motion. The proposed ME/MC method was evaluated with simulations, phantom and patient studies. Two experts in dentomaxillofacial radiology assessed the diagnostic importance of the resulting motion artifact suppression. The quality of the reconstructed images was improved after motion compensation, and most of the image artifacts were eliminated. Quantitative analysis by comparison to a reference image and by calculation of a sharpness metric agreed with the qualitative observation. The results are promising, and further evaluation is required to assess the clinical value of the proposed method.

Objectives: The aim of this study was to evaluate and summarise features of currently and formerly available cone beam CT (CBCT) devices from 1996 to 2019. Additionally, a recommendation for standardised reporting of CBCT characteristics was provided. Methods and materials: Information about the features of all available CBCT devices was obtained from the manufacturers’ available data. Moreover, site visits to newly developed CBCT machines’ manufacturers were performed in order to obtain relevant information. Results: A total of 279 CBCT models from 47 manufacturers located in 12 countries (Brazil, China, Denmark, Finland, France, Germany, Italy, Japan, Republic of Korea, Slovakia, Thailand, and USA) could be listed. Overall, wide variations in CBCT features and technical specifications were identified. Conclusions: CBCT in dentomaxillofacial radiology is a generic term applicable to a broad range of CBCT machines and features. Experimental outcomes and literature statements regarding radiation doses, imaging performance and diagnostic applicability of dental CBCT cannot be simply transferred from one CBCT model to another considering a wide variation in technical characteristics and clinical diagnostic performance. The information tabulated in the present study will be later provided on the International Association of DentoMaxilloFacial Radiology website ( www.iadmfr.one ).

Assessing the possible biological effects of exposure to low doses of ionizing radiation (IR) is one of the prime challenges in radiation protection, especially in medical imaging. Today, radiobiological data on cone beam CT (CBCT) related biological effects are scarce. In children and adults, the induction of DNA double strand breaks (DSBs) in buccal mucosa cells and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxo-dG) and antioxidant capacity in saliva samples after CBCT examination were examined. No DNA DSBs induction was observed in children nor adults. In children only, an increase in 8-oxo-dG levels was observed 30 minutes after CBCT. At the same time an increase in antioxidant capacity was observed in children, whereas a decrease was observed in adults. Our data indicate that children and adults react differently to IR doses associated with CBCT. Fully understanding these differences could lead to an optimal use of CBCT in different age categories as well as improved radiation protection guidelines. ispartof: SCIENTIFIC REPORTS vol:10 issue:1 ispartof: location:England status: published

This critical review discusses the clinical challenges for patient-specific and indication-oriented dentomaxillofacial cone beam computed tomography (CBCT). Large variations among units and protocols may lead to variable degrees of diagnostic and three-dimensional model accuracy, impacting both specific diagnostic tasks and treatment planning. Particular indications, whether diagnostic or therapeutic, may give rise to very specific challenges with regard to CBCT unit and parameter setup, considering the required image quality, segmentation accuracy, and artifact level. Considering that dental materials are in the field of view needed for diagnosis or treatment planning, artifact expression is a dominant factor in proper CBCT selection. The heterogeneity of dental CBCT units and performances may highly impact the scientific results. Thus research findings cannot be simply generalized as published evidence, and a demonstrated clinical applicability for a specific indication should not be simply extrapolated from one CBCT unit to another.

OBJECTIVE: The aim of this study was to quantitatively assess the performance of metal artifact reduction (MAR) algorithms on the volume of metal cylinders, considering the influence of materials, positions, and fields of view (FOVs), by using 3 cone beam computed tomography (CBCT) devices (NewTom VGi evo, Picasso Trio, and ProMax 3-D Max). STUDY DESIGN: Nine phantoms containing cylinders of amalgam, copper-aluminum (CuAl) metal alloy, and titanium, combined in up to 3 positions, were scanned by using 2 different FOVs. MATLAB software was used to evaluate the differences between volumes before and after MAR application, and the possible interference of materials, positions, and FOVs. Wilcoxon's test and the Kruskal-Wallis test were used at a level of significance of 5%. RESULTS: In general, images containing amalgam and CuAl showed a significant difference in volume before and after MAR application. However, no significant difference after MAR was observed (P > .05) relative to positions and FOVs. MAR had an impact on the cylinder volumes only in the NewTom VGi evo and ProMax 3-D Max scanners. CONCLUSIONS: The performance of MAR algorithms in volume correction of metal objects is dependent on the materials and the CBCT unit. ispartof: ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY ORAL RADIOLOGY vol:130 issue:3 pages:328-335 ispartof: location:United States status: published