Accuracy of implant height and width measurement with triaxial rotation method based on cone-beam CT.

Objective: To investigate the accuracy of implant height and width measurement in the mandibular and maxillary first molar region based on cone-beam CT (CBCT) data, and to establish an accurate method for bone measurement in the implant region. Materials and methods: CBCT images of 122 patients with implant in mandibular or maxillary first molar region were retrospectively collected. Two methods were used to measure sagittal height (SH), coronal height (CH), sagittal width (SW), and coronal width (CW) of implants. Method 1 (general method): the images were analyzed using the built-in software NNT 9.0 software. SHl, CHl, SWl, and CWl were measured on the reconstructed sagittal and coronal based on the radiologist's own experience. Method 2 (triaxial rotation method): the raw data were demonstrated in Expert mode of NNT 9.0 software, in which the coronal axis and sagittal axis were rotated paralleling to the long axis of the implant for reconstruction, and then SH2, CH2, SW2, and CW2 were measured on the reconstructed sagittal and coronal images. The results of two methods were compared with the actual implant size (H0, W0). Paired T-test was performed for statistical analysis. Dahlberg formula was used to check the measurement error. Results: For method 1, there was no significant differences between SHl and H0 (P > 0.05), but significant differences between CHl and H0, SWl and W0, and CWl and W0 (P < 0.05). For method 2, there were no significant differences between all measurements and actual size (P > 0.05). The random error range measured using Dahlberg formula was 0.157-1.171 mm for general method and 0.017-0.05 mm for triaxial rotation method. Conclusion: The triaxial rotation method is accurate for implant height and width measurements on CBCT images and could be used in pre-operatively bone height and width measurement of potential implant sites.

The exploration of a compound cone-beam CT contrast agent for diagnosis of human extracted cracked tooth.

Objectives: This study aims to investigate the use of sodium iodide (NaI), dimethyl sulfoxide (DMSO), ethyl alcohol, and ethyl acetate as cone-beam CT (CBCT) contrast agents for diagnosing cracked teeth. The optimal delay time for detecting the number of crack lines beyond the dentino-enamel junction (Nd), the number of cracks extending from the occlusal surface to the pulp cavity (Np), and the depth of the crack lines was explored. Methods: 14 human extracted cracked teeth were collected, 12 were used for enhanced scanning, and 2 were used for exploring the characteristic of crack lines. The teeth were scanned in 3 CBCT enhanced scanning (ES) modes: ES1 using meglumine diatrizoate (MD); ES2 using NaI and DMSO, ES3 using NaI, DMSO, ethyl alcohol and ethyl acetate. Three delay times (15mins, 30mins, and 60mins) were set for scanning. Nd, Np, and depth of crack lines were evaluated. Results: There were totally 24 crack lines on 12 cracked teeth. Nd was 10 in ES1 at 60mins, 24 in ES2 at 60mins and 24 in ES3 at 15mins. Np was 1 in ES1 at 60mins, 10 in ES2 at 60mins and 21 in ES3 at 60mins, and there were significantly different among them (p < 0.01). The average depth presented on ES3 was significantly deeper than ES1 and ES2 (p < 0.01). Conclusion: NaI, DMSO, ethyl alcohol and ethyl acetate show potential as contrast agents for enhanced CBCT scanning in diagnosis of cracked teeth and their depth in vivo. A delay time of 15 min is necessary to confirm the existence of crack lines, while a longer delay time is required to ascertain if these crack lines extend to the pulp cavity.

Exploring the potential of ChatGPT as an adjunct for generating diagnosis based on chief complaint and cone beam CT radiologic findings.

AIM: This study aimed to assess the performance of OpenAI's ChatGPT in generating diagnosis based on chief complaint and cone beam computed tomography (CBCT) radiologic findings. MATERIALS AND METHODS: 102 CBCT reports (48 with dental diseases (DD) and 54 with neoplastic/cystic diseases (N/CD)) were collected. ChatGPT was provided with chief complaint and CBCT radiologic findings. Diagnostic outputs from ChatGPT were scored based on five-point Likert scale. For diagnosis accuracy, the scoring was based on the accuracy of chief complaint related diagnosis and chief complaint unrelated diagnoses (1-5 points); for diagnosis completeness, the scoring was based on how many accurate diagnoses included in ChatGPT's output for one case (1-5 points); for text quality, the scoring was based on how many text errors included in ChatGPT's output for one case (1-5 points). For 54 N/CD cases, the consistence of the diagnosis generated by ChatGPT with pathological diagnosis was also calculated. The constitution of text errors in ChatGPT's outputs was evaluated. RESULTS: After subjective ratings by expert reviewers on a five-point Likert scale, the final score of diagnosis accuracy, diagnosis completeness and text quality of ChatGPT was 3.7, 4.5 and 4.6 for the 102 cases. For diagnostic accuracy, it performed significantly better on N/CD (3.8/5) compared to DD (3.6/5). For 54 N/CD cases, 21(38.9%) cases have first diagnosis completely consistent with pathological diagnosis. No text errors were observed in 88.7% of all the 390 text items. CONCLUSION: ChatGPT showed potential in generating radiographic diagnosis based on chief complaint and radiologic findings. However, the performance of ChatGPT varied with task complexity, necessitating professional oversight due to a certain error rate.

Patterns of stress distribution of endodontically treated molar under different types of loading using finite element models-the exploring of mechanism of vertical root fracture.

INTRODUCTION: The purpose of this study was to explore the mechanism of vertical root fracture (VRF) using three-dimensional finite element models (FEMs). METHODS: An endodontically treated mandibular first molar with a subtle VRF was collected and scanned with cone beam CT (CBCT). Three finite element analysis models were created: Model 1 had the actual endodontically treated root canal size; Model 2 had the same root canal size as the contralateral homonymous tooth; and Model 3 had the root canal size expanded by 1 mm based on Model 1. Different types of loading were performed on these 3 FEMs. The stress distribution on the cervical, middle, and apical planes was analyzed, and the maximum stress on the root canal wall was calculated and compared. RESULTS: In Model 1, the maximum stress around the root canal wall occurred in the cervical part of the mesial root under vertical masticatory force and in the middle part of the mesial root under buccal and lingual lateral masticatory forces. Additionally, there was a stress change zone in a bucco-lingual direction that corresponded with the actual fracture line. In Model 2, the maximum stress around the root canal was in the cervical part of the mesial root under both vertical and buccal lateral masticatory forces. For Model 3, the stress distribution was similar to that of Model 1, but greater under buccal lateral masticatory force and occlusal trauma force. In all three models, the maximum stress around the root canal wall was in the middle part of the distal root under occlusal trauma force. CONCLUSIONS: The uneven stress around the root canal in the middle part (presented as a stress change zone in a bucco-lingual direction) may be the cause of VRFs.

Development of a predictive model for identifying previously undetected vertical root fractures.

This study aimed to develop a predictive model to screen for undetected vertical root fractures (VRFs) in root canal treated teeth. We included 95 root canal treated teeth with suspected VRFs; 77 for training and 18 for validation. Following clinical and cone-beam CT parameters were recorded: sex, tooth type, coronal restoration, time interval from completion of endodontic treatment to definitive diagnosis (TI), type of bone loss (BL), apical extent of root filling (AR) and the ratio of root filling diameter to the actual diameter in the coronal (1/3TA) and middle (2/3TA) root thirds. A predictive model p = 1/(1 - e-x ) was generated, where x = -7.433 + 1.977BL + 1.479 (2/3TA) + 1.102 AR; the sensitivity and specificity were 0.852 and 0.875 for training and 0.917 and 0.833 for validation. VRF teeth were more likely to have vertical bone loss and overfilled root canals. This model had a high diagnostic efficacy for VRFs.

Diagnosis of in vivo vertical root fracture using deep learning on cone-beam CT images.

OBJECTIVES: Evaluating the diagnostic efficiency of deep learning models to diagnose vertical root fracture in vivo on cone-beam CT (CBCT) images. MATERIALS AND METHODS: The CBCT images of 276 teeth (138 VRF teeth and 138 non-VRF teeth) were enrolled and analyzed retrospectively. The diagnostic results of these teeth were confirmed by two chief radiologists. There were two experimental groups: auto-selection group and manual selection group. A total of 552 regions of interest of teeth were cropped in manual selection group and 1118 regions of interest of teeth were cropped in auto-selection group. Three deep learning networks (ResNet50, VGG19 and DenseNet169) were used for diagnosis (3:1 for training and testing). The diagnostic efficiencies (accuracy, sensitivity, specificity, and area under the curve (AUC)) of three networks were calculated in two experiment groups. Meanwhile, 552 teeth images in manual selection group were diagnosed by a radiologist. The diagnostic efficiencies of the three deep learning network models in two experiment groups and the radiologist were calculated. RESULTS: In manual selection group, ResNet50 presented highest accuracy and sensitivity for diagnosing VRF teeth. The accuracy, sensitivity, specificity and AUC was 97.8%, 97.0%, 98.5%, and 0.99, the radiologist presented accuracy, sensitivity, and specificity as 95.3%, 96.4 and 94.2%. In auto-selection group, ResNet50 presented highest accuracy and sensitivity for diagnosing VRF teeth, the accuracy, sensitivity, specificity and AUC was 91.4%, 92.1%, 90.7% and 0.96. CONCLUSION: In manual selection group, ResNet50 presented higher diagnostic efficiency in diagnosis of in vivo VRF teeth than VGG19, DensenNet169 and radiologist with 2 years of experience. In auto-selection group, Resnet50 also presented higher diagnostic efficiency in diagnosis of in vivo VRF teeth than VGG19 and DensenNet169. This makes it a promising auxiliary diagnostic technique to screen for VRF teeth.

Establishment of Narrow Root Fracture Models Using Modified Temperature Cycling Method and Diagnosis Using Different Cone-Beam CT Units.

Aim: Using a modified thermal cycling method to establish narrow root fracture models and evaluate the diagnosis efficiency of them using four different cone-beam CT (CBCT) units. Methodology. Fifty-six intact teeth were selected, and the crowns of the teeth were embedded using general purpose acrylic resin. 50 root fracture models were established by soaking these teeth in liquid nitrogen and hot water cyclically; 6 teeth were used as the negative control. All the 56 teeth were scanned with the smallest voxel size of four different CBCT units (NewTom VGi, Planmeca Promax 3D Max, Kavo 3D eXam, and Soredex Scanora3D). 10 teeth were randomly selected, and the roots were sliced using slow-speed saw to obtain horizontal root sections. Scanning electron microscope (SEM) was used to measure the width of the fracture lines (FLs). The CBCT images were evaluated for the presence or absence of fracture lines. Accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for the diagnosis of FLs using the four CBCT units. Results: Fifty narrow root fracture models were successfully established, and 25 root sections with 45 FLs were acquired. The width of FLs was from 3.43 µm to 143 µm; 32.2% of the points had width under 25 µm, while only 9.6% of them had width over 75 µm. The accuracy was 0.41, 0.54, 0.41, and 0.30 for NewTom VGi, Planmeca Promax 3D Max, Kavo 3D eXam, and Soredex Scanora3D, respectively. Conclusions: The modified temperature cycling method is a simple and effective method to establish narrow root fracture models, and the diagnosis efficiency for these narrow fracture lines was quite poor using all the four different CBCT units.

Using deep learning to distinguish malignant from benign parotid tumors on plain computed tomography images.

Objectives: Evaluating the diagnostic efficiency of deep-learning models to distinguish malignant from benign parotid tumors on plain computed tomography (CT) images. Materials and methods: The CT images of 283 patients with parotid tumors were enrolled and analyzed retrospectively. Of them, 150 were benign and 133 were malignant according to pathology results. A total of 917 regions of interest of parotid tumors were cropped (456 benign and 461 malignant). Three deep-learning networks (ResNet50, VGG16_bn, and DenseNet169) were used for diagnosis (approximately 3:1 for training and testing). The diagnostic efficiencies (accuracy, sensitivity, specificity, and area under the curve [AUC]) of three networks were calculated and compared based on the 917 images. To simulate the process of human diagnosis, a voting model was developed at the end of the networks and the 283 tumors were classified as benign or malignant. Meanwhile, 917 tumor images were classified by two radiologists (A and B) and original CT images were classified by radiologist B. The diagnostic efficiencies of the three deep-learning network models (after voting) and the two radiologists were calculated. Results: For the 917 CT images, ResNet50 presented high accuracy and sensitivity for diagnosing malignant parotid tumors; the accuracy, sensitivity, specificity, and AUC were 90.8%, 91.3%, 90.4%, and 0.96, respectively. For the 283 tumors, the accuracy, sensitivity, and specificity of ResNet50 (after voting) were 92.3%, 93.5% and 91.2%, respectively. Conclusion: ResNet50 presented high sensitivity in distinguishing malignant from benign parotid tumors on plain CT images; this made it a promising auxiliary diagnostic method to screen malignant parotid tumors.

Cross-sectional study of posterior tooth root fractures in 2015 and 2019 in a Chinese population.

OBJECTIVES: This study aimed to compare posterior tooth root fractures in endodontically treated teeth versus nonendodontically treated teeth in the Chinese population. MATERIALS AND METHODS: We investigated 500 root fractured posterior teeth in 461 Chinese patients. The clinical information (age, sex of patients, tooth type) were recorded. The fractured teeth were divided into endodontically treated root fractured (ETRF) teeth and nonendodontically treated root fractured (NETRF) teeth. The morphology of the fractured root (circular, oval, other), the orientation of fracture lines (vertical and non-vertical), the restorations performed (crown, filling, non-filling), and the position of the teeth in the dental arch (normal, misaligned) were evaluated based on cone-beam computed tomography images. These data were compared between 2015 and 2019. ETRF% was calculated as ETRF/ETRF + NETRF. Vertical% was calculated as vertical/vertical + non-vertical. RESULTS: There were 177 ETRF teeth and 323 NETRF teeth in this population. The total ETRF% was 29.3% in 2015 and 37.6% in 2019 (P = 0.087). The proportion of vertical root fracture in the ETRF group increased significantly in 2019 compared with that in 2015 (46.2% vs. 80.2%, P = 0.000). The ETRF% in female patients increased by 16.8%, but increased by only 1.2% in male patients in 2019 compared with that in 2015. The ETRF% of mandibular and maxillary premolars increased by 48.5% and 29.3%, respectively. The proportion of crown restoration increased by 2.4% in 2019 compared with that in 2015 in the ETRF group. CONCLUSIONS: The proportion of NETRF teeth and non-vertical root fractures in posterior teeth is high in this Chinese population. The number of vertical root fractures in endodontically treated teeth increased significantly from 2015 to 2019. CLINICAL RELEVANCE: More attention should be paid to endodontic treatment factors in the occurrence of root fractures, especially as female patients and premolars are more susceptible.

Exploring the use of enhanced cone-beam CT technique to diagnose vertical root fracture.

OBJECTIVES: To explore the feasibility of using sodium iodide (NaI)+dimethyl sulfoxide (DMSO)+ethyl alcohol+ethyl acetate as a cone-beam CT (CBCT) contrast agent in the diagnosis of vertical root fracture (VRF). METHODS: 21 endodontically treated VRF teeth of 21 patients were collected in this study. All these 21 teeth were confirmed subtle fracture lines under transillumination, the number and position of fracture lines were recorded. All these patients had CBCT routine scanning (RS1) before extraction. After extraction, the teeth was performed micro-CT scanning and 3 in vitro CBCT scanning: CBCT routine scanning in vitro(RS2), CBCT enhanced scanning using meglumine diatrizoate (MD) as contrast agent(ES1); and CBCT enhanced scanning using NaI+DMSO+ethyl alcohol+ethyl acetate as contrast agent(ES2). The number of fracture lines was evaluated on all the 5 scanning modes and the accuracy of diagnosis was calculated. RESULTS: In all, there were 43 fracture lines on the 21 teeth. The accuracy of detection of fracture lines of CBCT RS1, RS2, ES1, ES2 and micro-CT was 0%, 20.9% (9/43), 11.6% (5/43), 93% (40/43) and 95.3% (41/43) respectively. Significant differences were found between ES2 vs. RS2, ES2 vs. ES1 (p < 0.01); however, no significant difference was found between ES2 vs. micro-CT (p > 0.05). CONCLUSION: CBCT enhanced scanning using NaI+DMSO+ethyl alcohol+ethyl acetate as contrast agent could be a prospective technique in the diagnosis of VRF.

Fluorescence imaging of tumor immune contexture in immune checkpoint blockade therapy.

In the past decade, immunotherapy using immune checkpoint blockades (ICBs) has markedly changed the field of clinical oncology. However, the therapeutic efficacy of ICBs is closely related to the infiltration of immune cells in tumors and varies among different patients. There are still patients whose treatment effect is poor or even unresponsive. Due to different tumor immune contexture and highly complex regulation of immune network, immunoimaging techniques emerge and develop quickly. Fluorescence imaging, as a whole-body and non-invasive imaging technique, is regarded as a potential molecular imaging technique for immunotherapy by using a variety of fluorescent probes. In this review, we summarize the fluorescence imaging used in immune checkpoint blockade therapies: 1) evaluate the presence, subtype and abundance of T cells in tumors; 2) monitor the activation of T cell; 3) identify the immune regulators expressed on T and tumor cells. Moreover, for some theranostic nanoparticles, they could integrate fluorescence imaging and photoimmunotherapy as a whole.

Comparison of diagnosis of cracked tooth using contrast-enhanced CBCT and micro-CT.

OBJECTIVES: To evaluate the diagnostic accuracy using sodium iodide (NaI) and dimethyl sulfoxide (DMSO) as contrast agent in cone beam computed tomography (CBCT) scanning, and compare this with micro-CT. METHODS: 18 teeth were cracked artificially by soaking them cyclically in liquid nitrogen and hot water. After pre-treatment with artificial saliva, the teeth were scanned in four modes: CBCT routine scanning without contrast agent (RS); CBCT with meglumine diatrizoate (MD) as contrast agent (ES1); CBCT with NaI + DMSO as contrast agent (ES2); and micro-CT (mCT). The number of crack lines was evaluated in all four modes. Depth of crack lines and number of cracks presented from the occlusal surface to the pulp cavity (Np) in ES2 and micro-CT images were evaluated. RESULTS: There were 63 crack lines in all 18 teeth. 45 crack lines were visible on ES2 images as against four on the RS and ES1 images (p<0.05) and 37 on micro-CT images (p>0.05). Further, 34 crack lines could be observed on both ES2 and micro-CT images, and the average depth presented on ES2 images was 4.56 ± 0.88 mm and 3.89 ± 1.08 mm on micro-CT images (p<0.05). More crack lines could be detected from the occlusal surface to the pulp cavity on ES2 images than on micro-CT images (22 vs 11). CONCLUSION: CBCT with NaI +DMSO as the contrast agent was equivalent to micro-CT for number of crack lines and better for depth of crack lines. NaI + DMSO could be a potential CBCT contrast agent to improve diagnostic accuracy for cracked tooth.

Predictive factors in the treatment of oral squamous cell carcinoma using PD-1/PD-L1 inhibitors.

Due to immune impairment and lymphocyte enrichment of oral squamous cell carcinoma (OSCC), anti-PD-1/PD-L1 therapy is regarded as a potential treatment option. However, tumor heterogeneity, differences in the immune conditions of patients, and the interrelation between tumor cells and stromal cells within the tumor microenvironment (TME) could affect the therapeutic efficacy of immune checkpoint blockades. Therefore, to maximize the benefit of blockade PD-1/PD-L1 axis, to find an efficient predictor (the possible clinical parameters or biological factors) before treatment are of great importance. In this review, we discuss the advantages of anti-PD-1/PD-L1 therapy for OSCC patients and find three respects that are currently available in predicting curative effect. Firstly, OSCC with high PD-L1 expression evaluating by immunohistochemistry (high tumor proportion score (TPS) and combined positive score (CPS)) are considered to be suitable for anti-PD-1/PD-L1 therapy. Secondly, gene-level predictive biomarkers including high metastatic mismatch repair deficiency (dMMR) signature or enrichment of interferon-γ and PD1 signaling pathway is expected to be favorable factors. Besides, PET/CT parameters (SUVmax, MTV, TLG) are proved to be correlated with PD-L1 expression, and some newly developed immunoPET probes are enlarging the application of PET/CT in predicting therapeutic efficacy of PD-1/PD-L1 inhibitors.

Assessment of true vertical root fracture line in endodontically treated teeth using a new subtraction software - A Micro-CT and CBCT study.

This study aimed to find true facture lines in endodontically treated teeth on CBCT images using digital subtraction and to evaluate the influence of width of facture lines in the diagnosis. Thirty-two endodontically treated teeth with vertical root fractures (VRFs) from 30 patients were included in this study. The CBCT images of the patients and the micro-CT images of extracted teeth were imported into our digital subtraction software to distinguish the true facture lines from the streak artefacts. Of them, 23(71.87%) teeth did not present true fracture lines on the CBCT images (CBCT negative), and 9 (28.13%) teeth presented true fracture lines on the CBCT images (CBCT positive). The width of the facture lines was significantly different between these two groups (P < 0.05). To summarise, for in vivo endodontically treated teeth with subtle VRFs, many true fractures lines could not be demonstrated on CBCT images and wider fractures could be better distinguished.

Diagnosis of cracked teeth using cone-beam computed tomography: literature review and clinical experience.

Cone-beam computed tomography (CBCT) has been widely used in diagnosis of vertical root fractures (VRFs) in recent years. According to the American Association of Endodontists (AAE) classification, there are five types of cracked teeth and VRF is one of them. Due to the variability and overlapping of the cracks and fractures, some narrow fractures on the roots of VRFs could not be detected by CBCT, and some wide cracks on the crown of cracked teeth could be detected by CBCT. In this review, we firstly discussed the value of CBCT in the diagnosis of the AAE five types of cracked teeth and presented CBCT manifestations of some typical cases. Secondly, we summarized the factors influencing the diagnosis of cracks/fractures using CBCT, namely, CBCT device-related factors, patient-related factors, and evaluator-related factors. The possible strategies to improve the diagnostic accuracy in the clinic practice are also discussed in this part. Finally, we compared the differences of root fractures with lateral canals and external root resorption on CBCT images.

An extensive sclerosing odontogenic carcinoma in mandible: a case report and literature review.

Sclerosing odontogenic carcinoma (SOC) is a primary intraosseous carcinoma of the jaw that was listed as a separate entity for the first time in the latest version of the World Health Organization classification of Head and Neck Tumors (2017). In this report, we present a case of SOC involving a circuitous diagnostic process because of the inadequately detailed biopsy findings and inherent impression based on the imaging manifestations. Through an extensive literature review, the histopathological and immunohistochemical features of the disease were briefly summarized. Radiological findings of SOC have been characterized in detail, and an imaging classification scheme has been proposed to further discuss the diversity of radiographic features. Due to the rarity of the disease, a comprehensive understanding of SOC is needed, and close collaboration between clinicians, radiologists, and pathologists is crucial to avoid misdiagnosis.

Using Omniscan-Loaded Nanoparticles as a Tumor-Targeted MRI Contrast Agent in Oral Squamous Cell Carcinoma by Gelatinase-Stimuli Strategy.

In this study, the tumor-targeted MRI contrast agent was prepared with gelatinase-stimuli nanoparticles (NPs) and Omniscan (Omn) by double emulsion method. The size, distribution, morphology, stability, drug loading, and encapsulation efficiency of Omn-NPs were characterized. The macroscopic and microscopic morphological changes of NPs in response to gelatinases (collagenases IV) were observed. The MR imaging using Omn-NPs as a contrast agent was evaluated in the oral squamous cell carcinoma models with Omn as a control. We found clear evidence that the Omn-NPs were transformed by gelatinases and the signal of T1-weighted MRI sequence showed that the tumor-to-background ratio was significantly higher in Omn-NPs than in Omn. The peak point of time after injection was much later for Omn-NPs than Omn. This study demonstrates that Omn-NPs hold great promise as MRI contrast agent with improved specificity and prolonged circulation time based on a relatively simple and universal strategy.