A Basic Study for Predicting Dysphagia in Panoramic X-ray Images Using Artificial Intelligence (AI)-Part 1: Determining Evaluation Factors and Cutoff Levels.

BACKGROUND: Dysphagia relates to quality of life; this disorder is related to the difficulties of dental treatment. PURPOSE: To detect radiographic signs of dysphagia by using panoramic radiograph with an AI system. METHODS: Seventy-seven patients who underwent a panoramic radiograph and a videofluorographic swallowing study were analyzed. Age, gender, the number of remaining teeth, the distance between the tongue and the palate, the vertical and horizontal hyoid bone position, and the width of the tongue were analyzed. Logistic regression analysis was used. For the statistically significant factors, the cutoff level was determined. The cutoff level was determined by using analysis of the receiver operations characteristic (ROC) curve and the Youden Index. RESULTS: A significant relationship with presence of dysphagia was only observed for the vertical hyoid bone position. The area under the curve (AUC) was 0.72. The cutoff level decided for the hyoid bone was observed to be lower than the mandibular border line. CONCLUSIONS: In cases where the hyoid bone is lower than the mandibular border line on a panoramic radiograph, it suggests the risk of dysphagia would be high. We will create an AI model for the detection of the risk of dysphagia by using the assessment of vertical hyoid bone position.

A deep transfer learning approach for the detection and diagnosis of maxillary sinusitis on panoramic radiographs.

To investigate the use of transfer learning when applying a deep learning source model from one institution (institution A) to another institution (institution B) for creating effective models (target models) for the detection of maxillary sinuses and diagnosis of maxillary sinusitis on panoramic radiographs. In addition, to determine appropriate numbers of training data for the transfer learning. Source model was created using 350 panoramic radiographs from institution A as training data. Transfer learning was performed by adding 25, 50, 100, 150, or 225 panoramic radiographs as training data from institution B to the source model; this yielded the target models T25, T50, T100, T150 and T225. Each model was then evaluated using test data that comprised 40 images from institution A, 30 images from institution B. The performance indices (recall, precision and F1 score) for detecting the maxillary sinuses by the source model exceeded 0.98 when using test data A from institution A, but they deteriorated when using test data B from institution B. In the evaluation of target models using test data B, model T25 showed improved detection performance (recall of 0.967). The diagnostic performance of model T50 for maxillary sinusitis exceeded 0.9 in sensitivity. Transfer learning, which involves applying a small amount of data to the source model, yielded high performances in detecting the maxillary sinuses and diagnosing the maxillary sinusitis on panoramic radiographs. This study serves as a reference when adapting source models to other institutions.

Tooth Coronal Index: A Novel Tool For Age Estimation on Cone-Beam Computed Tomography

ABSTRACT Objective: To evaluate dental age assessment reliability through Tooth Coronal Index (TCI) method. Material and Methods: The cone-beam computed tomography (CBCT) scans of 160 individuals aged between 20-70 years were analyzed in the present study. The height of the crown, i.e., coronal height, and the height of the coronal pulp cavity, i.e., coronal pulp cavity height, of mandibular second premolars and first molars were calculated and then TCI was measured. The actual age of a subject was compared with TCI of tooth and the acquired data were subjected to Pearson's correlation and unpaired t-tests. Results: Negative correlation was observed between the real age and TCI of mandibular first molar (r = -0.094, p=0.382) and second premolar (r = -0.176, p=0.0961. Statistically significant difference was observed between actual age and TCI for mandibular second premolar and first molar (p<0.001). Conclusion: Tooth coronal index has the potential to estimate age of an individual on CBCT scans. It is simple, cost-effective than histological methods and can be applied to both living and unknown dead.

3D imaging of proximal caries in posterior teeth using optical coherence tomography.

Optical coherence tomography (OCT) can create cross-sectional images of tooth without X-ray exposure. This study aimed to investigate the diagnostic accuracy of 3D imaging of OCT for proximal caries in posterior teeth. Thirty-six human molar teeth with 51 proximal surfaces visibly 6 intact, 16 slightly demineralized, and 29 distinct carious changes were mounted to take digital radiographs and 3D OCT images. The sensitivity, specificity and area under the receiver operating characteristic curve (AUC) for the diagnosis of enamel caries and dentin caries were calculated to quantify the diagnostic ability of 3D OCT in comparison with digital radiography. Diagnostic accuracy was evaluated by the agreement with histology using weighted Kappa. OCT showed significantly higher sensitivity, AUC and Kappa values than radiography. OCT can be a safer option for the diagnosis of proximal caries in posterior teeth that can be applied to the patients without X-ray exposure.

Diagnosis of Occlusal Caries with Dynamic Slicing of 3D Optical Coherence Tomography Images.

Detecting the extent of occlusal caries is a clinically important but challenging task required for treatment decision making. The aim of this study was to assess the diagnostic power of 3D swept-source optical coherence tomography (OCT) for evaluation of occlusal caries in comparison with X-ray radiography. Extracted human molars not exhibiting American Dental Association (ADA) criteria advanced caries were mounted in a silicone block and digital dental radiographs were captured from the buccal side. Subsequently, occlusal surfaces were scanned with a prototype Yoshida Dental OCT. Thirteen examiners evaluated the presence and extent of caries on radiographs and dynamically sliced 3D OCT video images, using a 4 level scale-0: intact; 1: enamel demineralization without cavitation; 2: enamel caries with cavitation; 3: dentin caries with or without cavitation. Sensitivity, specificity and area under operating characteristic curves (Az) were statistically analyzed (α = 0.05). Reliability analysis showed an excellent agreement among the 13 examiners for both methods. The OCT presented a significantly higher sensitivity and Az value for the detection of caries compared to radiographs (p < 0.05). Radiography showed especially low sensitivity for dentin caries (0-2 versus 3). Dynamic slicing of 3D OCT volumes is a powerful adjunct tool to visual inspection to diagnose the dentin occlusal caries in vitro.

Frequency and Characteristics of Mesiodens in Indian School Children: A Retrospective Radiographic Study

Abstract Objective: To determine the frequency and characteristics of mesiodens in Indian school children. Material and Methods: 1232 radiographs of patients attending the Department of Oral Medicine and Radiology of the age group of 4-15 years studied for the present retrospective study. The intraoral periapical radiographs and occlusal radiographs of the premaxilla were examined to determine the presence of mesiodens. The data regarding the presence of mesiodens, number, position, location on the arch, shape and associated complications were recorded. Results: Eleven patients had 14 mesiodens, with a frequency of 0.8%. The ratio of boys to girls was 1.2:1. Maximum mesiodens observed in the age group of 7-9 years. Most of the mesiodens were conical in shape and found on the palatal side. Fifty percent of the mesiodens were unerupted. The majority of patients (57.1%) had vertically positioned mesiodens. Midline diastema was the most common complication due to mesiodens (66.7%). Conclusion: Routine check-up during the primary dentition and mixed dentition stages helps for early detection of mesiodens and thus preventing complications. Early identification is useful for planning comprehensive management, initiating proper consultation and referral for evaluation and treatment.

A NEWLY DEVELOPED PHANTOM FOR PHYSICAL QUALITY ASSURANCE OF DENTAL CONE-BEAM COMPUTED TOMOGRAPHY.

Two phantoms for a performance evaluation of cone-beam computed tomography (CBCT) were developed and their efficiency was tested. The first phantom, for low-contrast resolution, consisted of an acrylic circular plate with three 0.5-1.0 mm diameter rods. These rods enable the user to visually evaluate the limit of observation. The second phantom, for geometric distortion, especially focused on the z-axis and consisted of two tabular acryl plates crossed perpendicularly with 1.0 mm-wide grooves in a grating form every 10.0 mm. The distances between the grooves on the axial and coronal images were evaluated. Five CBCT modalities were assessed using these phantoms. The contrast resolutions differed for each apparatus and set of exposure parameters. In terms of geometric distortion, some distortion was observed at the periphery of the field of view for both the axial and z-axis planes. These results suggest that our new phantoms can be used to evaluate CBCT.

Evaluation of lateral pterygoid muscles in painful temporomandibular joints by signal intensity on fluid-attenuated inversion recovery images.

OBJECTIVES: Pathological changes of the lateral pterygoid muscle (LPM) have been investigated using various modalities, including magnetic resonance (MR) imaging and electromyography. Fluid-attenuated inversion recovery (FLAIR) is an MR sequence that we hypothesized can be used to evaluate abnormalities of the LPM. The purpose of this study was to analyze the FLAIR signal intensity of the LPM in painful temporomandibular joints (TMJs) and investigate the pathological changes of the muscle. METHODS: The study was based on 149 TMJs of 77 patients who were referred for MR imaging of the TMJ. Patients rated their degree of pain during chewing and mouth opening using a visual analog scale (VAS). Regions of interest were placed over the superior and inferior heads of the LPM and gray matter on FLAIR sagittal images. Using the signal intensity of gray matter as a reference, the signal intensity ratio (SIR) of the LPM was calculated. Spearman's rank-correlation coefficient was used to analyze the correlation between the SIR and the VAS score (p < 0.05). RESULTS: A significant correlation was present between the SIR on FLAIR images and the VAS score. CONCLUSIONS: These results suggest that the FLAIR signal intensity of the superior and inferior heads of the LPM significantly increases as TMJ pain becomes more severe. Thus, FLAIR could be useful in assessing the relationship between the MR signals of the LPM and clinical symptoms.

Prevalence of hypercementosis in a saudi arabian population: a cone beam computed tomography study

Objective: to determine the prevalence of hypercementosis in a Saudi Arabian population. material and methods: a total of 642 CBCT scans from patients comprising 4471 teeth were incorporated in the study sample. all teeth were analyzed for the presence of hypercementosis in sagittal, axial and coronal plains by two qualified and experienced observers. the characteristics of the involved tooth in terms of gender, jaw and location were recorded from the CBCT scans. the obtained data were statistically analyzed using SPSS 21.0. the reliability of measurements was evaluated by kappa statistics. results: out of total 642 subjects hypercementosis was observed in 31 patients (4.82 percent) and 43 teeth (0.96 percent). Eight (2.68 percent) maxillary 1st molars, 6 (1.88 percent) mandibular 1st molars, 5 (1.46 percent) maxillary second molars, 7 (1.95 percent) mandibular 2nd molars, 9 (4.76 percent) maxillary 3rd molars and 8 (3.58 percent) mandibular 3rd molars were observed to have hypercementosis. among males, 4.76 percent were affected with hypercementosis as compared to 4.86 percent of females (p=0.97). likewise, no significant difference in the occurrence of hypercementosis was observed between maxillary and mandibular arches or between sides (p>0.05). conclusion: the prevalence of hypercementosis in a Saudi population was found to be 4.82 percent with respect to patients and 0.96 percent with respect to teeth. No significant propensity for gender, jaw and arch side was noted.

Three-Rooted Mandibular First Molars in a Saudi Arabian Population: A CBCT Study

Objective: To know the prevalence three-rooted mandibular first molars in a Saudi Arabian population by using CBCT. Material and Methods: A total of 428 CBCT scans in the database of the College of Dentistry, Jouf University, Kingdom of Saudi Arabia were analyzed. All well-developed permanent mandibular first molars were analyzed for the presence of extra root in three dimensions and the reconstructed volumetric images by two qualified and experienced observers. The total incidence, distribution and comparison regarding gender, bilateral and unilateral appearance, and the side of occurrences of these permanent three-rooted mandibular first molars were analyzed by the Chi-square test. The level of significance was set at 5%. Results: The CBCT scans of 14 subjects had three rooted mandibular first molars with a prevalence of 3.27%. The prevalence in males and females was 2.96% respectively, with no significant differences between genders (p=0.865). The frequency of bilateral three-rooted mandibular first molars was 1.16%, with unilateral frequencies of 1.40% and 0.70% on the right and left sides, respectively. No significant relationship between sides (p=0.981) and the bilateral prevalence of three-rooted mandibular first molars (p=0.668) was observed. Conclusion: Dental practitioners must be aware of the fact that though it is rare, an extra or third root can be present in mandibular first molars and CBCT can aid in accurate diagnosis of the presence of third root.

A Cone Beam Computed Tomography Study of the Prevalence of Pulp Stones in a Saudi Arabian Adolescent Population

Objective: To assess the prevalence of pulp stones using Cone Beam Computed Tomography (CBCT) in a Saudi Arabian adolescent population. Material and Methods: CBCT scans of 237 individuals compromising of 1018 teeth were examined. All teeth were analyzed in three dimensions and the presence of pulp stones were identified as a round or oval shaped dense structures in the pulp space. The location of involved tooth in terms of arch, side involved and the status of the tooth were documented. Statistical analysis was carried out by applying Chi-square test. The level of significance was set at 5%. Results: Pulp stones were observed in 119 out of the 237 participants, and in 118 teeth out of 1018 teeth examined, with the patient prevalence of 50.2% and tooth prevalence 10.6%. Pulp stones were observed in 76 (51.3%) of males and 43 (48.3%) of females, with no significant difference (p>0.05). A nonsignificant difference was also noted when maxillary and mandibular arches and the left and right sides were compared. Pulp stones were observed more frequently observed in molars and in carious (8.8%) and restored teeth (17.1%). Conclusion: The prevalence of pulp stones was high in molars and in carious and restored teeth. No significant difference was noticed between gender, arch and side of tooth involved with pulp stones.

Radiopacity Measurement of Restorative Resins Using Film and Three Digital Systems for Comparison with ISO 4049: International Standard.

This study compared Ultra Speed Occlusal Film (USOF) and 3 digital systems in determining the radiopacity of 5 different restorative resins in terms of equivalents of aluminum thickness. Whether those digital systems could be used to determine whether radiopacity was in line with International Organization for Standardization (ISO) recommendations was also investigated. Disks of each of 5 restorative resins and an aluminum step wedge were exposed at 65 kVp and 10 mA on USOF and imaged with each digital system. Optical density on the film was measured with a transmission densitometer and the gray values on the digital images using Image J software. Graphs showing gray value/optical density to step wedge thickness were constructed. The aluminum equivalent was then calculated for all the resins using a regression equation. All the resins were more radiopaque than 1 mm of aluminum, and therefore met the ISO 4049 recommendations for restorative resins. Some resins showed statistically higher aluminum equivalents with digital imaging. The use of traditional X-ray films is declining, and digital systems offer many advantages, including an easy, fast, and reliable means of determining the radiopacity of dental materials.

Effect of display monitor devices on intra-oral radiographic caries diagnosis.

OBJECTIVES: Recent developments in digital computer technology have enabled radiological diagnosis to be performed using a monitor screen. In medical radiography, the importance of monitors has been shown in many diseases. Digital imaging and communication in medicine (DICOM)-compatible monitors are widely used. However, the effect of monitors on the diagnosis of oral disease has not yet been clarified and remains controversial. The aims of this study are to compare the caries diagnostic ability between DICOM monitors and other monitors and to examine if monitor capability affects the diagnosis. MATERIALS AND METHODS: One hundred proximal surfaces of 50 extracted human upper premolar teeth were used as specimens. Intra-oral radiographs of all specimens were taken digitally. Three types of monitors were compared in terms of caries diagnostic ability: a DICOM standard-compatible monitor, a standardized personal computer (PC) monitor, and a tablet PC. Six oral radiologists diagnosed each radiograph independently. Areas under the receiver operating characteristic (ROC) curve were generated and compared. RESULTS: Area under the ROC curve (AUC) of the DICOM monitor, PC monitor, and tablet PC was 0.68147, 0.67002, and 0.60189, respectively. There was no significant difference between the DICOM monitor and the PC monitor, but the tablet PC showed significantly lower accuracy. There were no significant differences among the monitors for dentin caries (p > 0.05). CONCLUSIONS: DICOM-compatible monitors and PC monitors have similar capabilities, but tablet PCs showed lower diagnostic accuracy, especially for superficial caries. CLINICAL RELEVANCE: Appropriate monitors are needed for radiographic diagnosis on monitor screens.

Relationships between third-molar juxta-apical radiolucencies and mandibular canals in panoramic and cone beam computed tomography images.

OBJECTIVE: This study aimed to determine the relationship between third-molar juxta-apical radiolucencies and mandibular canals on panoramic and cone beam computed tomography (CBCT) images. STUDY DESIGN: Forty-two patients were included in this retrospective study. The root apices and the relationships of the juxta-apical radiolucencies to the mandibular canals were evaluated on both panoramic and CBCT images. The McNemar test (P < .05) was used to compare panoramic with CBCT findings. RESULTS: Root apices were visualized clearly with CBCT in most cases for which the apices were not seen clearly on panoramic images. Similarly, juxta-apical radiolucencies were separate from the mandibular canals with CBCT in most cases. CONCLUSIONS: The present study found that there is no consistent intimate relationship between juxta-apical radiolucencies and the mandibular canals. Similar studies with larger sample sizes are required to further confirm these findings.

Exposure time reduction of secondary radiographs used in digital subtraction radiography in detecting intrabony change.

OBJECTIVES: Digital subtraction radiography (DSR) is a suitable technique for detecting incipient bone changes. However, in DSR, one or more follow-up radiographs must be taken. The aim of this study was to assess the possibility of reducing the exposure time for the radiographs that follow the initial one. METHODS: Maxillary premolar and molar radiographic images of a dry skull were taken with a digital radiography system. The initial radiographs, without bone chips, were taken at 0.32 and 0.16 s. Then, five bone chips (weight range 7-15 mg) were placed on the maxillary molar buccal side of the dry skull. Secondary radiographs were taken at 0.32-, 0.16-, 0.08-, 0.04-, and 0.02-s exposure times. For each bone chip, radiographs were taken three times. The secondary and initial images were subtracted to yield subtraction images. Four observers were asked to evaluate bone change visibility in the subtraction images. The Friedman test was used for statistical analysis. RESULTS: Significant differences were seen at each of the settings for the 0.32-s group (p = 1.24e-030) and 0.16-s group (p = 7.52e-009). By comparing the different groups, observer evaluations indicated that visibility changed when the secondary radiograph was taken at 1/8 of the exposure time of the initial radiograph. In both groups, the visibility of the 0.02-s subtraction image was significantly lower than that of the other subtraction images. CONCLUSION: In DSR, the exposure time of the secondary radiograph can be reduced to 1/4 of the exposure time of the initial radiograph.

Composition of the blood supply in the sublingual and submandibular spaces and its relationship to the lateral lingual foramen of the mandible.

OBJECTIVE: The purpose of this research was to contribute to minimizing arterial disruption during mandibular surgical procedures by clarifying the course of the arteries supplying the sublingual and submental regions. STUDY DESIGN: Heads of 75 human cadavers were dissected to identify the arterial supply of the sublingual and submental regions. Computed tomography scans were performed to visualize the lateral lingual foramina of the mandibles. RESULTS: The facial artery was found to contribute to the composition of almost half of the sublingual arteries studied. Furthermore, it was demonstrated that the arterial supply to an incisor tooth is often from the submental artery. CONCLUSIONS: Our data provide important information for coping with bleeding or hematoma occurring during surgical procedures in the mandibular region.

Retromolar canals as observed on cone-beam computed tomography: their incidence, course, and characteristics.

OBJECTIVE: The study aims at assessing the incidence, course, and characteristics of retromolar canals. STUDY DESIGN: The cone-beam computed tomography images of 171 subjects were evaluated for the presence, course, and pattern of occurrence of retromolar canals. RESULTS: Three types of retromolar canals namely A, B, & C were detected in 129 subjects. Type A branched off the mandibular canal distal to third molar to open into retomolar fossa, type B coursed between retromolar fossa and radicular portion of third molar, type C coursed from mandibular foramen anteroinferiorly to exit into retromolar fossa. The type B retromolar canal presented features distinguishing it from other types. CONCLUSIONS: Considerable number of individuals presented with retromolar canals emphasizing their significance in surgeries involving the retromolar area. The type B pattern, to the best of our knowledge, hasn't been reported by most researchers and hence, could be considered as an additional type of retromolar canal.

The effect of surrounding conditions on pixel value of cone beam computed tomography.

OBJECTIVE: The purpose of this study was to evaluate the reliability of pixel value in CBCT, especially with regard to the effect of surrounding objects that are presented outside the field of view (FOV). MATERIALS AND METHODS: This experiment used the GE Hi-Speed QXi, a multidetector helical computed tomography (MDCT) scanner, and the 3D Accuitomo FPD 8, a cone beam computed tomography (CBCT) scanner. Two types of phantoms were used, both of which contained Lipiodol Ultra Fluid (Lipiodol UF). The type A phantom was a target phantom for pixel value measurement while type B was used for the surrounding environment. For CBCT, the type A phantom was placed in a water bath, and 4 types of surrounding environmental conditions were created: (1) no other phantom present, (2) phantom type B also within the FOV, (3) half of phantom type B within the FOV, (4) phantom type B entirely outside the FOV but within the path of x-rays aimed at phantom A. RESULTS: In MDCT, pixel value (CT number) showed an almost linear correlation with the concentration of Lipiodol UF. In CBCT, on the other hand, pixel value was not linearly correlated with Lipiodol UF concentration. The position of the type B phantom affected pixel values in images of the type A phantom. CONCLUSIONS: Pixel value in CBCT may be affected by various conditions such as beam hardening and surrounding materials, and is therefore not reliable. Caution is essential when pixel values in CBCT are used to estimate bone density at potential implant sites.

Effect of computer assistance on observer performance of approximal caries diagnosis using intraoral digital radiography.

Logicon Caries Detector (LDDC) is the only commercially available computer-assisted diagnostic system for caries diagnosis. The object of this study is to elucidate the efficacy of LDDC when used by inexperienced dentists. Fifty extracted teeth were imaged using an RVG6000. Seven dentists who had just passed the Japanese National Dental Board Examination observed those images without LDDC (woLDDC) and assessed the probability that caries lesions were present, then re-assessed the same teeth using LDDC (wLDDC). The areas under the receiver operating characteristic curves (Az) were compared. No statistically significant difference was found between woLDDC Az values and wLDDC Az values when caries lesions of all depths were considered. When positive cases were restricted to caries lesions in the inner half of the enamel or to dentine caries lesions, however, wLDDC Az values were significantly larger than woLDDC (p = 0.043 and 0.018, respectively).

Evaluation of a limited cone-beam volumetric imaging system: comparison with film radiography in detecting incipient proximal caries.

OBJECTIVES: To assess the accuracy of a limited cone-beam volumetric imaging system in detecting incipient proximal caries. STUDY DESIGN: Fifty extracted premolars were used. On 100 surfaces examined, 71 proximal carious lesions were found; 47 were limited to the enamel, and 24 penetrated into the dentin. A limited cone-beam volumetric imaging system (CBVI), 3D Accuitomo (J. Morita Mfg. Corp., Kyoto, Japan), was used. Insight films (Eastman Kodak, Rochester, NY) were used for comparison. Seven experienced oral radiologists determined the presence of lesions using a continuous rating scale. The area measure (Az) values were calculated from the receiver operating characteristic curve obtained for each modality and observer. RESULTS: The mean Az-values were 0.63 +/- 0.02 for 3D Accuitomo and 0.63 +/- 0.03 for film. Analysis of variance showed no statistically significant difference between 3D Accuitomo and film. CONCLUSIONS: A limited CBVI, 3D Accuitomo, could not enhance the accuracy in detecting proximal carious lesions.