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Objective: The objective of this study was to evaluate the effectiveness of deep learning methods in detecting dental caries from radiographic images. Methods: A total of 771 bitewing radiographs were divided into two groups: adult (n = 554) and pediatric (n = 217). Two distinct semantic segmentation models were constructed for each group. They were manually labeled by general dentists for semantic segmentation. The inter-examiner reliability of the two examiners was also measured. Finally, the models were trained using transfer learning methodology along with computer science advanced tools, such as ensemble U-Nets with ResNet50, ResNext101, and Vgg19 as the encoders, which were all pretrained on ImageNet weights using a training dataset. Results: Intersection over union (IoU) score was used to evaluate the outcomes of the deep learning model. For the adult dataset, the IoU averaged 98%, 23%, 19%, and 51% for zero, primary, moderate, and advanced carious lesions, respectively. For pediatric bitewings, the IoU averaged 97%, 8%, 17%, and 25% for zero, primary, moderate, and advanced caries, respectively. Advanced caries was more accurately detected than primary caries on adults and pediatric bitewings P < 0.05. Conclusions: The proposed deep learning models can accurately detect advanced caries in permanent or primary bitewing radiographs. Misclassification mostly occurs between primary and moderate caries. Although the model performed well in correctly classifying the lesions, it can misclassify one as the other or does not accurately capture the depth of the lesion at this early stage.

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PURPOSE: Hall technique (HT) preformed metal crowns (PMCs) are allegedly oversized compared to conventional (C) PMCs. To investigate paediatric dentists' (PDs) perception of HT-PMCs and perception/ability to identify HT or C-PMCs on bitewings radiographs. METHODS: An online cross-sectional questionnaire including ten bitewings (five of each of HT/CPMCs) was sent to PDs across the globe. A PMC type score (from '10') was calculated. T test, Pearson's and Fischer's Chi-square, and Odd Ratios (OR) (p < 0.05). RESULTS: A total of 476 PDs from around the world responded. Most (97%) used PMCs in their practice. Most (98.7%) knew of, and 79% used HT-PMCs. A clear opinion shift, towards supporting HT, over time was noted (OR 11.154 [95% confidence interval (CI) 6.006-20.715]. A majority (67%) thought that HT/C-PMCs were similar radiographically. Only five PMCs were identified correctly [mean score 4.9 (± 1.73)]. A minority who thought that HT/C-PMCs were dissimilar scored higher than those who thought they were similar (5.31 ± 1.22; 4.68 ± 1.9, respectively, p < 0.00001). Nobody identified all ten PMCs. HT-PMCs were 4.63 times more identifiable than C-PMCs [(OR 24.857 CI 15.059-41.028) and (OR 5.361 CI 3.089-9.304)] for HT-PMCs and CP-MCs, respectively (p < 0.0001). CONCLUSIONS: PDs identified the PMC type in half of the bitewings. They perceived no clear radiographic difference between HT-PMCs and C-PMCs, but their chance of recognizing HT-PMCs was five times higher than C-PMCs. HT-PMC support was high.

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OBJECTIVES: To establish the prevalence and severity of external cervical resorption (ECR) in posterior teeth observed in bitewing (BW) radiographs in an epidemiological study of a 17-year-old patient population from community dentistry. Furthermore, to assess the potential predisposing factors for ECR. METHODS: Posterior BWs from 5596 patients (2717 females, 2879 males; mean age 17.8 years) were assessed by three observers in order to detect ECR (using Heithersay's classification system, severity classes 1-4). When ECR was suspected, cone beam CT (CBCT) was offered to verify diagnosis. Prevalence was estimated based on ECR suspected in BWs and finally in CBCT. Possible predisposing factors (orthodontic treatment, trauma, and periodontal disease) were recorded and assessed for association with ECR. RESULTS: In 41 patients, ECR was suspected in BWs (suspected prevalence 0.73%). 32 patients accepted CBCT examination, of which eight were verified to have ECR (final prevalence 0.18%). In 24 patients, other disease entities and abnormal tooth morphology, that had mimicked ECR in BWs, excluded ECR in CBCT. ECR severity ranged from class 1-3 in BW and 2-4 in CBCT. All but one case had not been diagnosed by the patient's community dentist. No statistically significant association between predisposing factors and ECR was identified. CONCLUSIONS: ECR had low prevalence in this adolescent population, as observed in both BWs and CBCT. Still, early detection of ECR is important for treatment prognosis, and attention should be paid to this disease entity when assessing BWs obtained for other diagnostic purposes. CBCT may subsequently aid in verifying the disease.

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This study aimed to evaluate the validity of a deep learning-based convolutional neural network (CNN) for detecting proximal caries lesions on bitewing radiographs. A total of 978 bitewing radiographs, 10,899 proximal surfaces, were evaluated by two endodontists and a radiologist, of which 2,719 surfaces were diagnosed and annotated with proximal caries and 8,180 surfaces were sound. The data were randomly divided into two datasets, with 818 bitewings in the training and validation dataset and 160 bitewings in the test dataset. Each annotation in the test set was then classified into 5 stages according to the extent of the lesion (E1, E2, D1, D2, D3). Faster R-CNN, a deep learning-based object detection method, was trained to detect proximal caries in the training and validation dataset and then was assessed on the test dataset. The diagnostic accuracy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and receiver operating characteristic curve were calculated. The performance of the network in the overall and different stages of lesions was compared with that of postgraduate students on the test dataset. A total of 388 carious lesions and 1,435 sound surfaces were correctly identified by the neural network; hence, the accuracy was 0.87. Furthermore, 27.6% of lesions went undetected, and 7% of sound surfaces were misdiagnosed by the neural network. The sensitivity, specificity, PPV, and NPV of the neural network were 0.72, 0.93, 0.77, and 0.91, respectively. In contrast with the network, 52.8% of lesions went undetected by the students, yielding a sensitivity of only 0.47. The F1-score of the students was 0.57, while the F1-score of the network was 0.74 despite the accuracy of 0.82. A significant difference in the sensitivity was found between the model and the postgraduate students when detecting different stages of lesions (p < 0.05). For early lesions which limited in enamel and the outer third of dentin, the neural network had sensitivities all above or at 0.65, while students showed sensitivities below 0.40. From our results, we conclude that the CNN may be an assistant in detecting proximal caries on bitewings.

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BACKGROUND: Globally, the direct cost of dental caries is approximately $298B yearly, consuming 5-10% of national healthcare budgets. Bitewing radiographs (BWR) are the standard method of diagnosing interproximal dental caries. In Japan, bitewing radiographs are rarely used. This retrospective observational study was conducted to measure the potential economic impact of carious lesions left undiagnosed and untreated due to this omission of bitewing radiographs. METHODS: The total number of existing carious lesions, the number of undiagnosed lesions, and costs of treating these lesions were calculated from the national database of Ministry of Health, Labor and Wellness in Japan between June 2013 and 2017. The number of affected teeth was estimated using prevalence data and undiagnosed lesions were estimated. The expense associated with treating progressed lesions was calculated using the standard Japanese fee structure. BWR trends were assessed, and analyses were performed to understand the differences between states and populations over time. RESULTS: The average number of BWR taken monthly per office was 48.3±1.1 (average ± SD). It was calculated that an average of 6,429,155 lesions went undiagnosed per month, 93.5 teeth per practice, and 1.6 teeth per patient. The cost of treating lesions that went undiagnosed and then progressed into more invasive restorations was estimated to be between $57M-$218M more (difference between NaF varnish and class II restorations), and $150M-$443M more (difference between Class II restoration and crown or crown with RCT). CONCLUSIONS: BWRs are crucial in diagnosing a significant number of carious lesions. There is considerable impact on health and cost to the national health system due to undiagnosed lesions. Practitioners need to be educated on reading and understanding BWR, and policy should be changed to cover BWR.

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AIM: To determine the bilateral occurrence of caries lesions in 5-12-year-old children, and to assess whether one bitewing photograph can predict caries size and occurrence in the homologous tooth on the other side of the mouth. STUDY DESIGN: The study was carried out on 222 medical files of children 5-12 years old who were first examined in the university dental clinic. The presence and size of the caries lesions in the first and second primary molars and first permanent molars were recorded. RESULTS: No correlation was found when comparing the caries lesion distribution of each tooth's proximal surface. Seventy-one of the X-rays demonstrated a single caries lesion in a first or second primary molar or in a first permanent molar on one side of the mouth, of which 21.3% demonstrated a single caries lesion in the collateral side, 43.6% demonstrated 2 or more lesions, and 35.21% did not have any caries lesion on the collateral side of the mouth. CONCLUSION: One bitewing cannot determine the presence and size of a caries lesion on the same site of the homologous tooth.

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OBJECTIVE: The aim of this study is to compare information provided by the 2 orientations of bitewing radiographs, horizontal (HBW) and vertical (VBW) taken in a dental school. METHODS AND MATERIALS: Radiographic records were reviewed at Tufts University School of Dental Medicine (TUSDM) for patients showing posterior bone loss who had both HBW and VBW. 320 records were reviewed with 6 criteria: visibility of crestal bone from the distal of the cuspids to the distal of the most posterior tooth, visibility of horizontal or angular bone loss, the crestal density of bone, visibility of interproximal contact areas, visibility of the entire anatomical crown, and visibility of furcations. RESULTS: Significantly higher number of VBW compared with HBW (P < 0.0001) showed the levels of alveolar bone loss (52.81% vs. 3.75%), the type of loss (angular or horizontal) (50.94% vs. 3.75%), the crestal bone density (28.75% vs. 0.63%), the contact areas (20.63% vs. 14.38%), and the furcations (43.44% vs. 1.25%). A greater number of HBW showed the entire anatomical crown compared with VBW. No significant difference was detected in the number of radiographs taken per HBW and VBW set. CONCLUSION: For patients with alveolar bone loss, VBW are superior to HBW when assessing bone levels, density, morphology, tooth furcations, and evaluating interproximal contact areas for caries. It is recommended that the vertical bitewing technique be taught as a standard in dental, dental hygiene, and dental assisting schools for adult patients showing evidence of posterior interdental bone loss.

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AIM AND OBJECTIVE: The purpose of this study is to evaluate the diagnostic accuracy of cone-beam computed tomography (CBCT) and extraoral bitewings in the detection of interproximal caries compared to intraoral bitewings. MATERIALS AND METHODS: Seven preserved cadaver heads with 106 teeth (molars, premolars, and canines) including 183 proximal surfaces were used. Five r adiographic modalities were studied: intraoral bitewings, extraoral bitewings, iCAT 3D, ProMax 3D high r esolution, and ProMax 3D low r esolution. Seven pediatric dental r esidents were r ecruited and calibrated as observers and asked to evaluate each proximal surface. Teeth were extracted, mounted, drilled, caries detection dye was applied, and the surfaces were examined under the light microscope. Interexaminer r eliability, sensitivity, specificity, and area under the curve values were compared. RESULTS: No significant differences were found in sensitivity, specificity, and area under the curve values between the five r adiographic modalities. R estorations may influence the accuracy of caries diagnosis. CONCLUSION: Cone-beam computed tomography radiographs and extraoral bitewings showed similar accuracies in detecting interproximal caries compared to intraoral bitewings. This suggests that with proper training and experience, CBCT and extraoral bitewings could be comparable to intraoral bitewings in detecting interproximal caries. CLINICAL SIGNIFICANCE: Cone-beam computed tomography and extraoral bitewings could potentially serve as alternatives to intraoral bitewings to diagnose proximal caries, especially when the CBCT study is needed for a specific diagnostic purpose.

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AIM: To perform a cross-sectional study on the carrier frequency of JP2 and non-JP2 genotypes of A. actinomycetemcomitans in Moroccan school children and relate the presence of these genotypes to the periodontal status in the mixed dentition. MATERIAL AND METHODS: A plaque sample from 513 children was analysed by PCR. JP2 genotype-positive subjects (n = 46), an equally sized group of non-JP2 genotype-positive subjects, and an A. actinomycetemcomitans-negative group were randomly chosen among the remaining subjects for clinical and radiographic examination. RESULTS: Among 513 children, 46 (9.0%) carried the JP2 genotype and 186 (36.3%) were positive for non-JP2 genotypes, whereas A. actinomycetemcomitans could not be detected in the remaining 281 subjects. Among 75 subjects with mixed dentition and selected for clinical examination, clinical attachment loss (CAL) ≥ 3 mm at two or more periodontal sites on primary teeth was found in the JP2 genotype-positive group only. In total, 6.7% of subjects with primary teeth present showed CAL ≥ 3 mm at two or more sites. CONCLUSIONS: The carrier frequency of the JP2 genotype of A. actinomycetemcomitans was at a comparable level to frequencies previously found in Moroccan adolescent populations. Clinical attachment loss, manifesting already in the primary dentition, was found only in the group of Moroccan children carrying the JP2 genotype of A. actinomycetemcomitans.

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OBJECTIVES: When bitewing radiographs are not possible (e.g. patients with special needs), oblique lateral radiographs may offer an alternative. The aims of this study were to assess the impact of horizontal projection angulation, focus-to-skin distance, exposure time and age of the patient on the equivalent radiation dose of several organs in the head and neck region by means of personal computer X-ray Monte Carlo (PCXMC) calculations and to assess the dose obtained from conventional bitewing radiographs. METHODS: PCXMC v. 2.0 software (STUK(®), Helsinki, Finland) was used to estimate the equivalent radiation doses and the total effective dose. Three exposure times, five age categories, two focus-to-skin distances and eight horizontal geometric angulations were assumed. The organs involved were the thyroid gland, oesophagus, salivary glands, bone marrow, oral mucosa, skull, cervical spine and skin. A similar calculation was also performed for bitewings taken with a rectangular collimator. Results and conclusion Bitewings taken with rectangular collimation decrease the radiation burden of the patient to 50%, compared with circular collimation. In the oblique lateral radiographs, focus-to-skin distance, patient's age and beam collimation had a significant impact on the equivalent doses measured in this study. Exposure time had a significant impact on the equivalent doses of the salivary glands, oral mucosa, skull and skin. Horizontal angulations had a significant impact on the equivalent doses of the thyroid gland, bone marrow, oral mucosa, skull and cervical spine. The total effective radiation dose was significantly influenced by all parameters investigated in this study.

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