OBJECTIVE:The aim of this study was to develop a radiomics model based on cone beam CT (CBCT) to differentiate odontogenic cysts (OCs), odontogenic keratocysts (OKCs), and ameloblastomas (ABs). METHODS:In this retrospective study, CBCT images were collected from 300 patients diagnosed with OC, OKC, and AB who underwent histopathological diagnosis. These patients were randomly divided into training (70%) and test (30%) cohorts. Radiomics features were extracted from the images, and the optimal features were incorporated into random forest model, support vector classifier (SVC) model, logistic regression model, and a soft VotingClassifier based on the above 3 algorithms. The performance of the models was evaluated using a receiver operating characteristic (ROC) curve and the area under the curve (AUC). The optimal model among these was then used to establish the final radiomics prediction model, whose performance was evaluated using the sensitivity, accuracy, precision, specificity, and F1 score in both the training cohort and the test cohort. RESULTS:The 6 optimal radiomics features were incorporated into a soft VotingClassifier. Its performance was the best overall. The AUC values of the One-vs-Rest (OvR) multi-classification strategy were AB-vs-Rest 0.963; OKC-vs-Rest 0.928; OC-vs-Rest 0.919 in the training cohort and AB-vs-Rest 0.814; OKC-vs-Rest 0.781; OC-vs-Rest 0.849 in the test cohort. The overall accuracy of the model in the training cohort was 0.757, and in the test cohort was 0.711. CONCLUSIONS:The VotingClassifier model demonstrated the ability of the CBCT radiomics to distinguish the multiple types of diseases (OC, OKC, and AB) in the jaw and may have the potential to diagnose accurately under non-invasive conditions.

Landmark detection is an essential foundation of cephalometric analysis, playing a crucial role in clinical diagnosis and treatment of orthodontic and orthognathic conditions. This paper proposes a novel framework that enables targeted learning and extraction of structural and medical features based on neural network. Specifically, our framework’s key components comprise Contour Sharpener, Coupling Transformer, and Progressively Targeted Feature Extraction Networks (PT-FENet). The Contour Sharpener intensifies contour features informed by the prior distributions of landmarks, enabling the network to learn anatomical structural features. The Coupling Transformer couples and transforms associated landmarks based on the similarity of features around medically related landmarks and the invariant structure of geometrically constrained landmarks to enhance the learning of anatomical structures and medical correlations among them. PT-FENet fully extracts multi-scale features and progressively targets the refinement of anatomical structural and medical features grounded in prior knowledge, thereby augmenting the attention towards detection information. Experimental results demonstrate that our method outperforms existing state-of-the-art methods on public dataset. Our method enables rapid batch processing of images for precise landmark detection, thus possessing significant value in clinical cephalometric analysis and orthodontic applications.

OBJECTIVE:The aim of this study was to develop a cone beam computed tomography (CBCT) radiomics-based model that differentiates between conventional and unicystic ameloblastoma (AB). METHODS:In this retrospective study, CBCT images were collected from 100 patients who had ABs that were diagnosed histopathologically as conventional or unicystic AB after surgical treatment. The patients were randomly divided into training (70) and validation (30) cohorts. Radiomics features were extracted from the images, and the optimal features were incorporated into 5 models: Logistic Regression, Support Vector Machine, Linear Discriminant Analysis, Random Forest, and XGBoost for prediction of tumor type. Model performance was evaluated using the area under the curve (AUC) from receiver operating characteristic analysis, sensitivity, specificity, accuracy, calibration curves, and decision curve analysis (DCA). RESULTS:The 20 optimal radiomics features were incorporated into the Logistic Regression (LR) model, which exhibited the best overall performance with AUC = 0.936 (95% confidence interval [CI] = 0.877-0.996) for the training cohort and AUC = 0.929 (95% CI = 0.832-1.000) for the validation cohort. The nomogram combined the clinical features and the radiomics signature and resulted in the best predictive performance. CONCLUSIONS:The LR model demonstrated the ability of radiomics and the nomogram to distinguish between the 2 types of AB and may have the potential to replace biopsies under noninvasive conditions.

OBJECTIVES:This study aims to evaluate the performance of ResNet models in the detection of in vitro and in vivo vertical root fractures (VRF) in Cone-beam Computed Tomography (CBCT) images.METHODS:A CBCT image dataset consisting of 28 teeth (14 intact and 14 teeth with VRF, 1641 slices) from 14 patients, and another dataset containing 60 teeth (30 intact and 30 teeth with VRF, 3665 slices) from an in vitro model were used for the establishment of VRFconvolutional neural network (CNN) models. The most popular CNN architecture ResNet with different layers was fine-tuned for the detection of VRF. Sensitivity, specificity, accuracy, PPV (positive predictive value), NPV (negative predictive value), and AUC (the area under the receiver operating characteristic curve) of the VRF slices classified by the CNN in the test set were compared. Two oral and maxillofacial radiologists independently reviewed all the CBCT images of the test set, and intraclass correlation coefficients (ICCs) were calculated to assess the interobserver agreement for the oral maxillofacial radiologists.RESULTS:The AUC of the models on the patient data were: 0.827(ResNet-18), 0.929(ResNet-50), and 0.882(ResNet-101). The AUC of the models on the mixed data get improved as:0.927(ResNet-18), 0.936(ResNet-50), and 0.893(ResNet-101). The maximum AUC were: 0.929 (0.908-0.950, 95% CI) and 0.936 (0.924-0.948, 95% CI) for the patient data and mixed data from ResNet-50, which is comparable to the AUC (0.937 and 0.950) for patient data and (0.915 and 0.935) for the mixed data obtained from the two oral and maxillofacial radiologists, respectively.CONCLUSIONS:Deep-learning models showed high accuracy in the detection of VRF using CBCT images. The data obtained from the in vitro VRF model increases the data scale, which is beneficial to the training of deep-learning models.

Abstract Objective This systematic review (SR) with meta-analysis aimed to evaluate the frequency of micronuclei in the oral mucosa exfoliated cells after cone-beam computed tomography (CBCT) examination. Methods We performed language-independent computer-assisted data searches using PubMed databases, Cochrane, Embase, Web of Science all databases, and Google Scholar. The literature on micronucleus (MN) frequency of clinical trials before and after CBCT examination was included. The frequency of MN in exfoliated cells of the human oral mucosa was the primary outcome of the study. All statistical analyses were performed with R (version 4.1.0), RStudio (version 2022.02.2 + 485) software, and Meta packages (version 5.2–0). Two reviewers independently assessed the quality of the included studies by the EPHPP (Effective Public Health Practice Project) Modified scale with minor modifications. The heterogeneity of the data was analyzed using I 2 statistics, in which I 2 > 50% was considered substantial heterogeneity. Results A total of 559 articles were selected through the search strategy. After screening titles and abstracts, nine full-text manuscripts were assessed for eligibility, and six observational studies were included in the meta-analysis. The present study showed a significant increase in MN frequency of human oral mucosal exfoliated cells 10 days after CBCT examination compared to baseline (SMD = − 0.56, 95%-CI = − 0.99 ~ − 0.13, p = 0.01). Because of the high heterogeneity among the studies (I 2 = 72%), after removing one study that was the main source of heterogeneity, excluding the study (I 2 = 47%), the common-effect model was chosen, and the meta-analysis also showed that the frequency of MN in human oral mucosa exfoliated cells increased significantly 10 days after CBCT examination (SMD = − 0.35, 95%-CI = − 0.59 ~ − 0.11, p = 0.004). Conclusion This review suggested that CBCT examination increases the frequency of micronuclei in oral mucosal exfoliated cells.

ObjectivesTo explore whether the inorganic nitrate has a protective effect on biological damage induced by cone-beam computed tomography (CBCT) and compare it with Vitamin C.Materials and methodsSixty Wistar rats were randomly separated into 6 groups: control group, irradiation (IR) group, NaNO3 group, IR + NaNO3 group, Vitamin C group, and IR + Vitamin C group. Rats were whole-body irradiated with CBCT four times. The absorbed dose of the skin surface was measured using thermoluminescent dosemeter chips and the mean whole-body absorbed dose was calculated. Peripheral blood was collected at 0.5 h and 24 h after irradiation. Bodyweight and organ index of rats before and after irradiation were analyzed. The bone marrow was taken for micronucleus test. Lymphocytes were isolated from peripheral blood for γ-H2AX immunofluorescence assay, apoptosis and reactive oxygen species (ROS) analysis. Total antioxidant capacity (TAC), malondialdehyde (MDA) and superoxide dismutase (SOD) in serum were detected.ResultsThe mean absorbed dose of four whole-body CBCT scans for rats was 73.04 mGy. Bodyweight and organ index before and after irradiation with X-ray had no significant differences. The micronuclei frequency of IR + NaNO3 and IR + Vitamin C groups showed a significant decrease than that in the IR group, which was not significantly different from that of the control group. The γ-H2AX foci rates in the IR + NaNO3 group and the IR + Vitamin C group were significantly lower than that in the IR group. In addition, the foci rate of the IR + NaNO3 group returned to the baseline level of the control group 24 h after CBCT scanning. The apoptosis of lymphocytes in rats did not increase. The IR + NaNO3 group (P < 0.001) or IR + Vitamin C group (P < 0.001) showed a significant increase in ROS positive cells rate with the control group, while were significantly lower than those in the IR group (P < 0.01). In addition, the ROS-positive cell rate in the IR + NaNO3 group was significantly lower than that in the IR + Vitamin C group. The MDA in the serum of rats increased significantly, while SOD and TAC decreased significantly at 0.5 h after irradiation.ConclusionsCompared with Vitamin C, inorganic nitrate had better preventive effects on biological damage induced by CBCT scans in rats.

BACKGROUND/AIMS Under-estimating the damage caused by trauma to the dental structures may delay treatment. Timely and accurate diagnosis remains challenging in clinical practice. Radiography is an important modality for the diagnosis of traumatic injuries. The aim of this study was to compare the efficacy of periapical radiography and cone beam computed tomography for the diagnosis of trauma to the anterior maxillary dentoalveolar region in children and adolescents. MATERIAL AND METHODS Images of patients who underwent both periapical radiography and cone beam computed tomography simultaneously because of trauma to the anterior maxillary region between January 2016 and January 2020 were analyzed retrospectively. Pairwise comparison between the receiver operating characteristic curves was performed to statistically compare the two methods for the diagnosis of crown fractures, root fractures, alveolar bone fractures and luxations, tooth resorption, and periapical radiolucencies. RESULTS A total of 190 patients met the inclusion criteria. There were 120 (63.2%) males and 70 (36.8%) females, with a mean age of 11.1 years (range: 6-17 years). A crown fracture was observed in 144 teeth, while a root fracture was observed in 71 teeth. Alveolar fracture and luxation were observed in 44 incisors. During follow-up, tooth resorption and periapical radiolucencies were observed in 25 and 33 teeth, respectively. Pairwise receiver operating characteristic curve analysis revealed that cone beam computed tomography was significantly superior to periapical radiography for the diagnosis of root fractures, alveolar fractures and luxations, and tooth resorption (p < .05). However, no significant differences were found for the diagnosis of crown fractures and periapical radiolucencies (p > .05). CONCLUSIONS Cone beam computed tomography in the low-dose mode was better for diagnosing root and bone fractures and resorption, but no different to periapical radiographs for crown fractures and periapical radiolucencies in pediatric patients.

目的 通过锥形束CT(CBCT)和DR根尖片对牙外伤冠根折诊断的准确性比较研究,对冠根折的临床诊断和评价提供重要参考.方法 对60颗急诊外伤疑似冠根折的患牙,分别进行DR根尖片和CBCT检查诊断并对其结果进行统计分析,计算2种诊断检查方法的灵敏度、特异度、阳性预测率和诊断符合率.结果 60颗冠根折的患牙,CBCT灵敏度100％,特异度100％,阳性预测率100％,诊断符合率100％;DR根尖片灵敏度29％,特异度43％,阳性预测率60％.CBCT与DR根尖片在冠根折诊断的准确性上,差异有明显统计学意义(P<0.05).结论 CBCT比DR根尖片在冠根折的诊断上更有显著优势.

Objective To investigate the difference in the richness and diversity of the parotid microflora between juvenile recurrent parotitis (JRP) and the normal children. Methods The parotid saliva specimens were obtained from JRP and normal children (34 specimens from JRP, 16 specimens from normal children)to analyze the diversity of the 16SrRNA gene sequence of of the microorganism using Illumina Hiseq 2500 PE250 high throughput sequencing platform. Results Compared with normal children, JRP had higher goods_coverage(P＜ 0.05), lower Chaol, abundance coverage estimator (ACE), Shannon (P＜ 0.05) and lower Simpson (P＞ 0.05). Conclusion Significant changes in the richness and diversity of parotid microflora between JRP and the normal children.

Objective To investigate the clinical application of the minimally-invasive surgery using small skin incision assisted by sialoendoscopy for the removal of the parotid gland stone. Methods A total of 6 cases with stones in the parotid ducts behind the anterior edge of masseter muscle were treated. The operation was performed under general anesthesia,a small skin incision was made just above the stone in the parotid duct located by the sialoendoscopy. Dissection was carried out carefully to reach the parotid duct avoiding to injure the facial nerve at the same time. The parotid duct was cut and the stones were totally removed. The parotid duct was sutured with a tube placed inside to prevent stenosis. Results The parotid ducts of all the cases resumed to be unobstructed immediately after the surgery,and were not obstructed again in half a year follow up. Conclusion This paradigm is highly recommended in the treatment of parotid gland sailolithiasis with the stones in the deep parotid duct.

Objective To evaluate the clinical effect of pulp revascularization procedures in the treatment of immature permanent teeth with apical periodontitis.Methods Sixteen immature permanent teeth with apical periodontitis were selected and received pulp revascularization procedures.These teeth were followed up for two years and the clinical effect was evaluated through clinical and radiographic examination.Results Continuation of root development was observed in most of these teeth, although their responses to pulp revascularization procedures varied.The electric pulp vitality test was positive in 13 teeth.All these 16 teeth showed the radiographic evidence of periapical wound healing and clinical evidence of resolution of signs and symptoms.The average healing time of the periapical wound was 4.1 months.The smaller periapical wounds generally disappeared three months after revasculatization, and the larger ones commonly needed 6-9 months.Twelve teeth were successful, 4 teeth improved.Conclusion The clinical effect of the pulp revascularization procedures in the treatment of immature permanent teeth with apical periodontitis was satisfactory.

Objective:To understand the epidemiological characteristics of maxillofacial injurie in the FunHill district.Methods:Data was derived from the Chinese National Injury Surveillance System(NISS) of the stomatological department(the emergency and outpatient)in the First Hospital of Fangshan district in 2016.The descriptive analysis was applied to depict general information,injuries events and clinical characteristics of maxillofacial injuries.Results:A total number of 1085 cases with maxillofacial injuries in 2016 were collected,including 719 males(66.3％)and 366 females(33.7％).The two leading causes of the maxillofacial injury were falls(53.9％)and road traffic(14.0％).The main nature of injuries were sharpcutopen injury(57.1％)and bruising(35.3％).The primary injured site is in the home of the age group of 1～5 years old.The age of 6～17 groups are more likely to be injured in the school and public places.The age of 18～59 groups have high in the road and street.The age of over 60 groups are more likely to be injured in the home.Conclusion:The establishment of the safe community could reduce the incidence if the maxillofacial injuries in many ways.

Objective To investigate the effect of splint treatment of the skeletal ClassⅠmalocclusion patients on condylar functional position and symmetry changes and diagnosis. Methods Thirty-four patients with skeletal Class I malocclusion were treated by occlusion splint. The MCD ( measures of the condyle displacement ) was used to compare condylar position between centric relation (CR) and centric occlusion (CO). The frequency, direction and magnitude of CO-CR difference were determined, and the changes of the symmetry of the bilateral condylar before and after the treatment evaluated. The patients were re-diagnosed after the treatment. Results After the splint treatment, the symmetry of the bilateral condylar was improved and 14. 7%(5/34) of the patients had different skeletal classification. 17. 6%(6/34) of the patients had different Angle’s classification. Conclusion The splint treatment improved the symmetry of the bilateral condylar in skeletal Class I malocclusion patients and the accuracy of the diagnosis.

目的：通过对北京地区口腔医疗机构从事放射诊疗工作人员的调查，了解其技术水平现状，以规范口腔医疗机构的放射诊疗操作和辐射防护管理。方法通过对在放射实践技术培训班的学员培训前、后分别开展问卷调查，进行基本情况分析和培训效果评价。结果接受调查的学员中，口腔医师或护士兼职做放射工作约占78％；学员普遍使用数字化设备；操作时以分角线技术为主；70％患者用手指固定采集设备；培训前、后效果对比辐射防护知识提升87％、影像学基础知识提升25％。结论基层口腔医疗机构的放射工作人员多为年轻医生或护士兼职，且人员流动性大；放射工作人员对牙片投照操作手法缺少技巧且不熟练。行业管理部门应重点加强基层口腔医疗机构放射工作人员投照实践技能及新设备新技术培训，法律法规和辐射防护知识等专项培训，以确保医疗机构放射工作人员及患者的身体健康和安全。

普通X线检查是埋伏牙临床诊断中最常用的方法，它可提供一般检查方法所不能提供的信息，但对于埋伏牙，由于拍摄角度和影像重叠的缘故，常无法清楚地显示牙的形态、位置及与邻牙的关系。近年来随着放射CT 技术和软件的飞速发展， CT三维重建在口腔正畸中的应用越来越广泛。目前锥束C T 已广泛应用于复杂牙槽外科手术［1‐3］口腔系局部重建、正畸疗效评价［4］口腔种植以及牙体牙髓复杂疾病的处理和颞颌关节病的诊断等。常规CT能够清楚显示牙齿和周围结构，但是费用高，放射剂量大而锥束CT 检查时间短，患者照射剂量明显减小，仅为大型高分辨CT 检查放射剂量的1／400［5］，我科对60例多生牙患者采用锥束CT投照，对其结果进行了判断和讨论。

目的 比较2种锥形束CT(CBCT)诊断牙根纵裂的准确性,评估根充物、观察面、牙根观察位置对CBCT诊断的影响.方法 纳入20例单根恒下颌前磨牙作为研究对象,牙根置于人下颌骨标本第一前磨牙牙槽窝内,根据先后不同处理步骤依次拍摄4次大视野及小视野CBCT,记录下列4种情况:无根纵裂+无根充物、无根纵裂+热牙胶根充、有根纵裂+无根充物、有根纵裂+热牙胶根充.2名牙体牙髓科主治医师对结果进行判读.结果 1)无论根管内是否存在根充物,小视野CBCT诊断牙根纵裂的灵敏度均明显高于大视野CBCT(P＜0.05).2)根管内存在根充物时,小视野CBCT及大视野CBCT正确诊断根纵裂的部位均是在轴位根尖1/3区.结论 不论根管内是否存在根充物,小视野CBCT均是诊断牙根纵裂的最佳选择.根管内存在根充物时,CBCT根尖1/3受伪影影响最小,诊断牙根纵裂的灵敏度最高.

The c-Kit pathway is important in the development of many mammalian cells and organs and is indispensable for the development of hematopoiesis, melanocytes, and primordial germ cells. Loss-of-function mutations in c-Kit lead to perinatal death in mouse embryos. Previously, c-Kit has been used as one of salivary epithelial stem or progenitor cell markers in mouse, its specific temporo-spatial expression pattern and function in developing murine submandibular gland (SMG) is still unclear. Here we used quantitative real-time PCR, in situ hybridization, and immunohistochemistry analysis to detect c-Kit expression during the development of the murine SMG. We found that c-Kit was expressed in the epithelia of developing SMGs from embryonic day 11.5 (E11.5; initial bud stage) to postnatal day 90 (P90; when the SMG is completely mature). c-Kit expression in the end bud epithelium increased during prenatal development and then gradually decreased after birth until its expression was undetectable in mature acini at P30. Moreover, c-Kit was expressed in the SMG primordial cord at the initial bud, pseudoglandular, canacular, and terminal end bud stages. c-Kit was also expressed in the presumptive ductal cells adjacent to the developing acini. By the late terminal end bud stage on P14, c-Kit expression could not be detected in ductal cells. However, c-Kit expression was detected in ductal cells at P30, and its expression had increased dramatically at P90. Taken together, these findings describe the spatial and temporal expression pattern of c-Kit in the developing murine SMG and suggest that c-Kit may play roles in epithelial histo-morphogenesis and in ductal progenitor cell homeostasis in the SMG.

OBJECTIVES:Mesenchymal stem cells (MSCs) are a reliable resource for tissue regeneration, but their molecular mechanisms of differentiation and proliferation remain unclear; this situation has restricted use of MSCs to a limited number of applications. A previous study of ours found a member of the epidermal growth factor family, epiregulin (EREG), to be involved in regulation of MSC differentiation. In the present study, we have used human dental stem cells from the apical papilla (SCAPs) to investigate the role of EREG on proliferation of MSCs.MATERIALS AND METHODS:SCAPs were isolated from apical papillae of immature third molars. Retroviral short hairpin RNA (shRNA) was used to silence EREG gene expression, and human recombinant EREG protein was used to stimulate SCAPs. SCAP proliferation was examined using tetrazolium dye colorimetric assay/cell growth curve. Western blotting was performed to detect expressions of extracellular signal-regulated protein kinases 1 and 2 (Erk1/2), mitogen-activated protein kinases 1 and 2 (MEK1/2), protein kinase B (Akt), p38 mitogen-activated protein kinase (p38 MAPK) and c-Jun N-terminal kinase (JNK).RESULTS:Depletion of EREG with shRNA inhibited SCAP proliferation and repressed phosphorylation of Erk1/2 and JNK. Human recombinant EREG protein promoted cell proliferation and enhanced Erk1/2, MEK and JNK phosphorylation in SCAPs. Furthermore, blocking MEK/Erk signalling with specific Erk1/2 inhibitor PD98059, or JNK signalling with specific inhibitor SP600125, abolished effects of EREG on cell proliferation.CONCLUSION:These findings indicate that EREG could enhance cell proliferation in dental tissue-derived MSCs by activating MEK/Erk and JNK signalling pathways.

多生牙又叫额外牙是形成与正常牙列之外的牙,与遗传和发育缺陷有关.上颌尖牙腭侧埋伏的发生率为1％[1],也有报道上颌尖牙埋伏的发生率在1％～3％[2].男性多于女性.好发于上颌,前牙区多于后牙区,腭侧较唇侧多[3,4],有时也见于下颌磨牙区.临床发现为摄取上颌多生牙纵断体层时,图像显示范围不能满足临床要求,于是,根据国人颌面骨发育特征及临床对影像显示范围的需求,对基托进行了改良.收集我科2008年5月至2009年12月,通过口内片及全颌曲面断层发现有多生牙患者66例,利用两种基托进行了临床应用与效果比对,探讨了改良基托的实用价值,报告如下.

Objective To evaluate alveolar bone changes in chronic periodontitis before and after treatment by CBCT. Methods Thirty patients with chronic periodontitis were selected and received initial treatment. The outcomes were evaluated clinically and by CBCT before and after treatment. The CBCT images were analyzed using the software of Newtom CBCT. The density of the alveolar bone in maxillary premolars area was measured and recorded. The data was statistically analyzed. Results The probing depth and attachment loss improved after treatment. The alveolar bone density was significantly increased after treatment(P <0. 05),and no significant change of alveolar bone resorption was observed before and after treatment( P > 0. 05). Conclusion CBCT could be used in evaluation of alveolar bone changes in chronic periodontitis. The methods of landmark identification was consistent and reproducible.