Accuracy of cone-beam computed tomography in imaging the components of the periodontal phenotype.

The components and dimensions of the periodontal and peri-implant phenotype have a high relevance in contemporary dental research and should be taken into consideration in the decision-making process in the management of a variety of clinical scenarios to optimize the outcomes of therapy. Various assessment methods for quantifying and classifying the phenotypical dimensions have emerged and developed in recent decades. Nevertheless, the use of cone-beam computed tomography (CBCT) scans remains the most commonly used approach worldwide. However, the accuracy to adequately imaging and measuring the dimensions of the hard and soft tissue components around teeth may represent a significant challenge in different clinical scenarios due to factors such as the age of the patient and motion during the scan, presence of metallic artifacts causing streaks and gray-value distortion, overlapping of soft tissue structures, machine performance, file processing, and small voxel size among others. These factors pose a particular challenge when tiny structures are under investigation, for example, the buccal/lingual bony or soft tissue layer of lower/upper incisors. Therefore, this review addresses the underlying technical information of the use of CBCT scans, and suggests some recommendations on the utilization of this method of assessment to optimally use it despite its' system-inherent limitations.

A content-aware chatbot based on GPT 4 provides trustworthy recommendations for Cone-Beam CT guidelines in dental imaging.

OBJECTIVES: To develop a content-aware chatbot based on GPT-3.5-Turbo and GPT-4 with specialized knowledge on the German S2 Cone-Beam CT (CBCT) dental imaging guideline and to compare the performance against humans. METHODS: The LlamaIndex software library was used to integrate the guideline context into the chatbots. Based on the CBCT S2 guideline, 40 questions were posed to content-aware chatbots and early career and senior practitioners with different levels of experience served as reference. The chatbots' performance was compared in terms of recommendation accuracy and explanation quality. Chi-square test and one-tailed Wilcoxon signed rank test evaluated accuracy and explanation quality, respectively. RESULTS: The GPT-4 based chatbot provided 100% correct recommendations and superior explanation quality compared to the one based on GPT3.5-Turbo (87.5% vs. 57.5% for GPT-3.5-Turbo; P = .003). Moreover, it outperformed early career practitioners in correct answers (P = .002 and P = .032) and earned higher trust than the chatbot using GPT-3.5-Turbo (P = 0.006). CONCLUSIONS: A content-aware chatbot using GPT-4 reliably provided recommendations according to current consensus guidelines. The responses were deemed trustworthy and transparent, and therefore facilitate the integration of artificial intelligence into clinical decision-making.

[Surgical removal of an atypically large extensive radicular cyst in the mandible: a case report.] / Atypisch grosse radikuläre Zyste. Operative Entfernung einer atypisch grossen ausgedehnten radikulären Zyste im Unterkiefer, ein Fallbericht.

The radicular cyst is the most common odontogenic cyst and is caused by inflammation. It can become atypically large, although the size of the radiographic osteolysis says nothing about the entity of the lesion. This case shows an unusually large multilocular radicular cyst expanding buccally from tooth 46 in a patient with severe autism who can only be treated under general anesthesia. The clinical and radiological picture as well as the intraoperative situation was more indicative of an aggressive cyst or benign tumor. The lesion was surgically completely removed and the teeth 46, 47 and 48 were extracted because of poor compliance and prognosis. Histopathology revealed a radicular cyst. There were no postoperative complications. After eight months, the lesions had almost completely reossified.

Accuracy of facial skeletal surfaces segmented from CT and CBCT radiographs.

The accuracy of three-dimensional (3D) facial skeletal surface models derived from radiographic volumes has not been extensively investigated yet. For this, ten human dry skulls were scanned with two Cone Beam Computed Tomography (CBCT) units, a CT unit, and a highly accurate optical surface scanner that provided the true reference models. Water-filled head shells were used for soft tissue simulation during radiographic imaging. The 3D surface models that were repeatedly segmented from the radiographic volumes through a single-threshold approach were used for reproducibility testing. Additionally, they were compared to the true reference model for trueness measurement. Comparisons were performed through 3D surface approximation techniques, using an iterative closest point algorithm. Differences between surface models were assessed through the calculation of mean absolute distances (MAD) between corresponding surfaces and through visual inspection of facial surface colour-coded distance maps. There was very high reproducibility (approximately 0.07 mm) and trueness (0.12 mm on average, with deviations extending locally to 0.5 mm), and no difference between radiographic scanners or settings. The present findings establish the validity of lower radiation CBCT imaging protocols at a similar level to the conventional CT images, when 3D surface models are required for the assessment of facial morphology.

CBCTs in a Swiss university dental clinic: a retrospective evaluation over 5 years with emphasis on radiation protection criteria.

OBJECTIVES: To retrospectively evaluate all cone-beam computed tomography (CBCT) scans acquired from 2017 to 2022 in a Swiss university dental clinic with particular emphasis on radiation protection aspects. MATERIAL AND METHODS: Radiological databases at the dental clinic of the University of Bern, Switzerland, were explored using a self-developed search algorithm. Data of all acquired CBCT from 01.01.2017 to 27.06.2022 were screened. Exposure parameters (exposure time, exposure angle, milliampere (mA), kilovoltage (kV), field of view (FOV) size), dose area product (DAP), age, and sex of the patient were recorded anonymously. The collected data were analyzed mainly descriptively. Correlations measured the statistical relationships between the variables. RESULTS: A total of 10,348 CBCT datasets were analyzed. Patient age ranged from 5 to 96 years (mean: 49.4 years, SD: 21.6 years). The number of CBCTs in patients under 25 years was around 20% each year. In total, 10,313 (99.7%) CBCTs were acquired in small to medium FOV (FOV up to 10 cm of height), and 35 (0.3%) in large FOV (height > 10 cm). DAPs of small FOVs were 518.3 ± 233.2 mGycm2 (mean ± SD), of medium FOV 1233 ± 502.2 mGycm2, and of large FOV 2189 ± 368.7 mGycm2. DAP (ρ = 0.4048, p < 0.0001) and kV (ρ = 0.0210, p = 0.0327) correlated positively with age. Reduced scan angle correlated with young age (rpb 0.2729, p < 0.001). mA did not correlate with age (p = 0.3685). CONCLUSIONS: This study demonstrates that certain well-known radiation protection aspects as the reduction of FOV, mA, kV, and scan angle were only partly considered. CLINICAL RELEVANCE: Known radiation protection aspects, especially in young patients, should be fully applied in regular clinical practice.

Motion correction for separate mandibular and cranial movements in cone beam CT reconstructions.

BACKGROUND: Patient motions are a repeatedly reported phenomenon in oral and maxillofacial cone beam CT scans, leading to reconstructions of limited usability. In certain cases, independent movements of the mandible induce unpredictable motion patterns. Previous motion correction methods are not able to handle such complex cases of patient movements. PURPOSE: Our goal was to design a combined motion estimation and motion correction approach for separate cranial and mandibular motions, solely based on the 2D projection images from a single scan. METHODS: Our iterative three-step motion correction algorithm models the two articulated motions as independent rigid motions. First of all, we segment cranium and mandible in the projection images using a deep neural network. Next, we compute a 3D reconstruction with the poses of the object's trajectories fixed. Third, we improve all poses by minimizing the projection error while keeping the reconstruction fixed. Step two and three are repeated alternately. RESULTS: We find that our marker-free approach delivers reconstructions of up to 85% higher quality, with respect to the projection error, and can improve on already existing techniques, which model only a single rigid motion. We show results of both synthetic and real data created in different scenarios. The reconstruction of motion parameters in a real environment was evaluated on acquisitions of a skull mounted on a hexapod, creating a realistic, easily reproducible motion profile. CONCLUSIONS: The proposed algorithm consistently enhances the visual quality of motion impaired cone beam computed tomography scans, thus eliminating the need for a re-scan in certain cases, considerably lowering radiation dosage for the patient. It can flexibly be used with differently sized regions of interest and is even applicable to local tomography.

Evaluation of Medication-Related Osteonecrosis of the Jaw (MRONJ) in Terms of Staging and Treatment Strategies by Dental Students at Different Educational Levels.

Background: The role of medication-related osteonecrosis of the jaw (MRONJ) as a dento-maxillo-facial pathology is becoming increasingly important due to its growing prevalence. The success of preventive and therapeutic measures relies mainly on the dentist's ability to correctly diagnose the disease. Methods: The aim of this study was to evaluate the skills of dental students of different educational levels in choosing the correct stage, diagnostics, and treatment option for MRONJ based on clinical and radiographic imaging (panoramic radiograph, CBCT). The study was designed as a cross-sectional cohort study. Twenty dental students were asked to complete a questionnaire in their third and fifth year of studies in which they had to correctly stage the disease, choose the radiological diagnostics and recommend the treatment. The control group contained experienced oral and maxillofacial surgeons. Results: With an overall performance of 59% (third year: 145.2/248 points; fifth year: 145.3/248 points), no statistically significant difference between the educational levels could be observed. The classification based on CBCT imaging was significantly more often correct compared to panoramic radiographs (p < 0.001). Conclusions: This study highlights students' lack of knowledge in staging, diagnostics, and treatment of MRONJ, even though the CBCT positively affected decision-making. No significant increase in knowledge could be confirmed through clinical education. This study highlights the need for students to catch up on MRONJ diagnostics and treatment planning. Further expansion of teaching in this disease's context and X-ray diagnostics is needed.

Vertical head rotation as major source of differences between time-separated digital cephalometric radiographs of patients acquired in one cephalostat X-ray device.

BACKGROUND: The purpose of the retrospective study was to analyze the reliability and repeatability of specific landmark-positions used in cephalometry to determine the major sources of absolute landmark position differences for repeated, time-separated (time-point I and II) digital cephalometric radiographs (CEPH) of the same patients. METHODS: 100 pairs of CPEHs from the database of a sample of adult patients (18 to 28 years) were analyzed by one calibrated observer and three landmark points (Sella: S, Nasion: N, Subspinale: A) were digitally marked using ImageJ-software. The coordinates of these points entered the evaluation using displacement vectors as primary endpoints between the coordinates of the landmarks in the two images as well as SNA-angles and the angle ω of SN relative to the floor. RESULTS: Displacement vectors between CEPHI and CEPHII were rather large (N: 7.95 ± 4.85 mm, S: 5.34 ± 3.50 mm, A: 4.81 ± 3.95 mm. SNA was rather stable between the two sequential radiographs (mean difference: 0.002° ± 1.85°). and did not correlate with age of the patient (SNAI: spearman-Rho: 0.0239, p = 0.8134; SNAII : spearman-Rho: 0.0244, p = 0.8096). Although the vertical angle ω did not differ between CEPHI and CEPHII (mean difference: 0.4° ± 4.7°, pwilcoxon = 0.8155), it showed a quadratic relationship (pF-statistic: < 2.2e-16) with the length of the displacement vector N. CONCLUSION: The significantly varying location of the reference points S, N and A between time-separated CEPHs of one patient can largely be explained by different angulation (head rotation within the sagittal plane) of the Frankfurt plane to the floor (horizontal plane).

Effectiveness of Telemedicine and Teledentistry after the COVID-19 Pandemic.

Telemedicine has become increasingly important worldwide over the last two decades. As a new field, it became known especially during the COVID-19 pandemic; this review presents fields of activity with special attention to opportunities and risks. Numerous areas of application offer the possibility for broad use in the medical and dental care landscape in diagnostics, therapy, rehabilitation, and decision advice across a spatial distance. Technical and semantic standards are required, and profiles and guidelines are increasingly defined and organized. Medical/dental consultations have been established in various regions around the world as a response to pandemic challenges and have made video and online emergency consultations possible. Telemedicine applications are already regularly used in medical/dental emergencies, regardless of the pandemic situation, both for transport by train and by plane, from which patients benefit. However, legal hurdles are often still unresolved, but infrastructure challenges both for provider, user hard- and software also complicate deployment. Problems are particularly prevalent in the absence of necessary internet coverage or among socially disadvantaged and vulnerable groups who cannot afford expensive equipment or do not know how to use the technology. Broad access must be enabled, and hardware and software interfaces and updates must be regularly checked and updated. Telemedicine might also improve access to and delivery of oral and general health care support both for rural and urban areas with low costs. Even though dentistry and many medical specialties are still performed clinically by means of practical/manual examination, there are areas of diagnostics where telemedicine applications can provide good support. Therefore, as conclusions, access, and delivery of telemedicine applications in dentistry and medicine should be expanded and improved to provide access to all population groups.

CBCT artefact-burden of zirconia-based as compared to titanium implants for different beam energies: an analytical approach.

Beam hardening artefacts induced by highly-dense material (e.g. metal) is a common quality issue in maxillofacial Cone Beam Computed Tomography (CBCT-) images. This experimental and analytical study investigated attenuation patterns of two typical dental implant materials: zirconia-ceramic and pure titanium. By application of different x-ray beam energies (60, 70, 80, 90 [kVp]) energy-dependent attenuation of these materials is assessed and the resulting artefact induction in the resulting CBCT-images evaluated. A zirconia (Y-TZP-) implant ([Formula: see text]: 4.1 mm) and a pure titanium rod ([Formula: see text]: 4.0 mm) were exposed in a commercial CBCT (3D Accuitomo 170). The raw two-dimensional (2D) projection radiographs the CBCT utilizes for three-dimensional reconstruction applied for acquisition of attenuation profiles through the circular central slice of the implant-phantom images. Distances the x-rays traverse through the implant-phantoms at this location were computed. Using this information and the linear attenuation coefficient, transmission and attenuation was computed for each material and beam energy. These data were related to beam hardening artefacts that were assessed in the axial reconstructions of the implants' CBCT images. Transmission of titanium for all peak kilovoltages (kVp) was higher and approximately 200% that of Y-TZP at 60 kVp versus 530% at 90 kVp. At 4 mm diameter transmission for Y-TZP was only approximately 5 % for all four beam-energies. In agreement with this finding, beam hardening artefacts for Y-TZP could not be reduced using higher energies, whereas for titanium they decreased with increasing energy. For the energy spectrum used in this study (60-90 kVp), beam hardening caused by titanium can be reduced using higher energies while this is not the case for zirconia-ceramic (Y-TZP).

Detectability of simulated apical lesions on mandibular premolars and molars between radiographic intraoral and cone-beam computed tomography images: an ex vivo study.

Adequate endodontic diagnostic is essential when making a therapy decision. Radiographic imagining acquisition methods (IAMs) are fundamental apical lesions of endodontic (ALE) origin diagnose tool. Thus, the aim of this research was to compare the simulated apical lesions (SALs) diagnose potential of digital intraoral radiography (DIR) and cone-beam computed tomography (CBCT), if there is a relationship between the IAMs, SALs-depth and their correct diagnose likelihood in human mandibular specimens' datasets. 1024 SALs were prepared in cancellous and cortical bone with different penetration depths. The SALs-stages were radiographed with CBCT and DIR. The IAMs were randomly evaluated by 16 observers in two trials. Possible SAL findings were analyzed according to a five-point scale. The null hypothesis established that SALs detection accuracy does not differ between CBCT and DIR. Significantly differences (first 0.935 and second trial 0.960) were found for the CBCT area under the curve when compared with the DIR (first 0.859 and second trial 0.862) findings. SALs of smaller size were earlier detected by CBCT. In SALs without cortical involvement the probability of detection increased from 90 to 100%. The SALs-depth had the highest detectability influence on cancellous bone lesions and CBCT SALs detectability was 84.9% higher than with DIR images. The CBCT diagnose reproducibility was higher than the one of DIR (Kappa CBCT 75.7-81.4%; DIR 53.4-57.1%). Our results showed that CBCT has a higher SALs IAM diagnosing accuracy and that SALs detection accuracy incremented as the SALs-size increased.

Viewing patterns regarding panoramic radiographs with different pathological lesions: an eye-tracking study.

OBJECTIVE: The aim of this study was to examine how dental students vary their viewing patterns of panoramic radiographs during different levels of dental education. METHODS: Two groups of students (total number = 48, n = 24) in different grades (second and fifth clinical semester) were compared. The second clinical semester participated twice, as during the second clinical semester a specific lecture on dental radiology and diagnosis is held. The first viewing took place at the beginning of the semester (2a), the second at the end of it (2e). The fifth semester (5e) represents students shortly before graduation. While viewing 20 panoramic radiographs showing specific pathologies, the eye movement was captured by an eye-tracker. After a maximum of 60 s per image, the students had to report a suspected diagnosis. Every panoramic radiograph included a pathological lesion which was diagnosed by an expert observer who also defined the areas of interest (AOI). The images were presented in the same order to each participant. The metric data recorded by the tracking-system included total time to first fixation, total fixation count, total gaze duration and coordinates of the fixation in and outside an area of interest. In addition, parameters like the completeness of scanning and the suspected diagnosis were analysed. Differences between the groups were assessed for statistical significance and associations between level of different grades, viewing time, completeness of scanning and correctness of diagnosis were computed. RESULTS: 2e was significantly faster (p < 0,001), whereas 5e was significantly (p < 0.001) more likely to diagnose correctly and also to scan more completely. Scanning duration did not significantly influence the correctness of diagnosis. The lower edges of the panoramic radiographs were not scanned as often as the centre of the image. Bony lesions were generally found to be difficult to interpret and significant findings located in the sinus were overlooked the most. CONCLUSION: The higher semester had a more complete viewing pattern and diagnosed correctly with a higher percentage. After hearing the mentioned lecture, the second semester scanned faster and mentioned the AOI more often but could not make a right diagnosis.

The effects of examiner fatigue on the diagnostic accuracy of dental radiographs.

OBJECTIVES: The aim of the study was to find out whether and to what extent the performance of dentists regarding diagnostic evaluation of dental radiographs is influenced by symptoms of fatigue. MATERIALS AND METHODS: Over a period of 40 minutes, 21 dentists evaluated a database of 96 randomly selected, infinitely repeating intraoral dental radiographs for the presence of periapical radiolucencies. Both before and after, participants were asked to assess their subjective fatigue using the Swedish Occupational Fatigue Inventory (SOFI), Visual Analogue Scale (VAS), and Numerical Rating Scale (NRS). Diagnostic accuracy was analyzed using the Receiver Operating Characteristics (ROC) method. Furthermore, the correlation between diagnostic accuracy and radiographic experience, image viewing time, and level of training was also evaluated. RESULTS: The study showed that despite increasing fatigue, the diagnostic accuracy of the examiners remained consistent with an average AUC value of 0.768 ± 0.091. Within the 40-min reporting period, no statistically significant fluctuations were found. The diagnostic accuracy varied depending on the radiographic experience: with many years of radiographic experience, the diagnostic accuracy increased. At the same time, the older study participants with greater radiographic experience became less tired compared to younger study participants during the examination. CONCLUSIONS: Although an increase in fatigue was observed during the 40-min examination, the diagnostic accuracy of the doctors remained constant. CLINICAL RELEVANCE: Due to the high workload which needs to be handled in a limited time, medical and dental professionals have reached a certain level of exposition to stress that can lead to physical fatigue. However, the increasing fatigue should not negatively influence the work of the doctors. The study shows that the radiodiagnostic accuracy remained the same.

Three-Dimensional Classification of Lower Third Molars and Their Relationship to the Mandibular Canal.

PURPOSE: To develop a novel classification making full use of radiographic three-dimensional (3D) information to describe the position, geometric configuration of a mandibular third molar (M3M) and its spatial relation to neighboring structures such as the mandibular canal (MC). The classification presented in this study helps to establish a common language and serves as a framework for further studies, for example, on 3D parameters influencing prognosis of the M3M and level of difficulty associated with its removal. MATERIAL AND METHODS: A total of 8 parameters were included in the classification including position, the cranio-caudal height, the number of roots of the M3M as well as its spatial relationship to the MC, its course, its deformation, and distance to the M3M. The classification was retrospectively applied to a sample of 483 patients and these data were statistically evaluated. RESULTS: The most commonly observed categories were the (+) vertical position (39.8%); the cranio-caudal height A (38.7%); 2 roots (83.2%); and the spatial relationship no contact caudal (37.5%). Contact between the M3M and inferior alveolar nerve was observed in 58% of all cases. A deformation of the MC was found in 81% of cases. CONCLUSIONS: Our novel classification aims to provide a more holistic description of parameters defining 3D M3M position, as well as its spatial relation to relevant neighboring structures. It creates a uniform terminology that can be applied in practice by surgeons and radiologists, and also serves as a foundation for further research projects, such that results from similarly designed studies could be compared.

Fractal dimension in CBCT images as predictor for MRONJ: a retrospective cohort study.

OBJECTIVE: To estimate boxcounting fractal dimension in a standardized approach in CBCT images of the mandible and maxilla in a group of patients with MRONJ in comparison to a healthy control group. MATERIAL AND METHODS: From our records, a study group consisting of 80 maxillary and mandibular CBCTs in 77 cases of patients having MRONJ was collected. The control group consisted of 84 mandibular and maxillary CBCTs in a total of 78 patients. Using the boxcounting method, fractal dimension (FD) was estimated in a standardized fashion either cranially to the apex of the canine (maxilla) or beneath the tooth apices of the lower molars in the bone area above the mandibular canal (mandible). Intra-observer reproducibility of the FD-measurements was assessed by 6 repeated measurements in 10 individuals. FD values were correlated to age and sex of the individuals as well as to region of interest (ROI) sizes. RESULTS: FD in the study group (1.684 ± 0.051) was roughly 3.5 % lower than in the control group (1.745 ± 0.026, p < 0.0001). Sex and age had a significant (p < 0.001) influence on FD values in the study group, yet not in the control group. FD values increased with age (study group, spearman-rho: 0.2895, p < 0.05) and also ROI size (both groups, p < 0.0001). Reproducibility was good (intra-class correlation coefficient (ICC): 0.87). CONCLUSIONS: Fractal dimension as assessed by boxcounting seems to be a good descriptor for MRONJ in jaw bones. Influence of age and sex on the outcome values needs to be further investigated in future studies. CLINICAL RELEVANCE: CBCTs could be assessed with respect to FD to obtain an overview of the disease status of MRONJ patients.

Memories of the first 50 years of the journal Dentomaxillofacial Radiology.

As Dentomaxillofacial Radiology celebrates 50 years of publication, some former editors who have helped the journal reach this milestone reminisce on their time at the helm of the journal.

A new approach to assessing emotional understanding.

This article describes (a) the origins of, (b) rationale underlying, and (c) preliminary validity evidence for, a new ability measure of emotional understanding (EU), a major component of emotional intelligence. A novel conceptual approach-the empathic agent paradigm (EAP)-provided the theoretical foundation. The EAP results in a veridical, logically defensible scoring key, a major development for the assessment of EI, which otherwise has relied on less defensible approaches. Validity evidence for test score interpretations of the Empathic Agent Paradigm Test (EAPT) was subsequently obtained in two studies. In Study 1, participants (N = 321) completed the EAPT (α = .72 at testlet level), along with measures of classical intelligence, the Big Five personality traits, and a situational judgment measure of EU. This study provides factorial, convergent, and discriminant validity evidence for EAPT test score interpretations. In Study 2 (N = 158), an important assumption about the response processes in the EAPT was verified experimentally, in the process providing further validity evidence for test score interpretations. In sum, findings suggest that the EAPT is a promising new maximum performance measure for the assessment of EU. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Projection-based improvement of 3D reconstructions from motion-impaired dental cone beam CT data.

PURPOSE: Computed tomography (CT) and, in particular, cone beam CT (CBCT) have been increasingly used as a diagnostic tool in recent years. Patient motion during acquisition is common in CBCT due to long scan times. This results in degraded image quality and may potentially increase the number of retakes. Our aim was to develop a marker-free iterative motion correction algorithm that works on the projection images and is suitable for local tomography. METHODS: We present an iterative motion correction algorithm that allows the patient's motion to be detected and taken into account during reconstruction. The core of our method is a fast GPU-accelerated three-dimensional reconstruction algorithm. Assuming rigid motion, motion correction is performed by minimizing a pixel-wise cost function between all captured x-ray images and parameterized projections of the reconstructed volume. RESULTS: Our method is marker-free and requires only projection images. Furthermore, it can deal with local tomography data. We demonstrate the effectiveness of our approach on both simulated and real motion-beset patient images. The results show that our new motion correction algorithm leads to accurate reconstructions with sharper edges, better contrasts and more detail. CONCLUSIONS: The presented method allows for correction of patient motion with observable improvements in image quality compared to uncorrected reconstructions. Potentially, this may reduce the number of retakes caused by corrupted reconstructions due to patient movements.