For patients with partial jaw defects, cysts and dental implants, doctors need to take panoramic X-ray films or manually draw dental arch lines to generate Panorama images in order to observe their complete dentition information during oral diagnosis. In order to solve the problems of additional burden for patients to take panoramic X-ray films and time-consuming issue for doctors to manually segment dental arch lines, this paper proposes an automatic panorama reconstruction method based on cone beam computerized tomography (CBCT). The V-network (VNet) is used to pre-segment the teeth and the background to generate the corresponding binary image, and then the Bezier curve is used to define the best dental arch curve to generate the oral panorama. In addition, this research also addressed the issues of mistakenly recognizing the teeth and jaws as dental arches, incomplete coverage of the dental arch area by the generated dental arch lines, and low robustness, providing intelligent methods for dental diagnosis and improve the work efficiency of doctors.
Humans ; Radiography, Panoramic/methods* ; Cone-Beam Computed Tomography/methods* ; Head ; Image Processing, Computer-Assisted/methods*

Objective To evaluate the accuracy of different convolutional neural networks (CNN),representative deep learning models,in the differential diagnosis of ameloblastoma and odontogenic keratocyst,and subsequently compare the diagnosis results between models and oral radiologists. Methods A total of 1000 digital panoramic radiographs were retrospectively collected from the patients with ameloblastoma (500 radiographs) or odontogenic keratocyst (500 radiographs) in the Department of Oral and Maxillofacial Radiology,Peking University School of Stomatology.Eight CNN including ResNet (18,50,101),VGG (16,19),and EfficientNet (b1,b3,b5) were selected to distinguish ameloblastoma from odontogenic keratocyst.Transfer learning was employed to train 800 panoramic radiographs in the training set through 5-fold cross validation,and 200 panoramic radiographs in the test set were used for differential diagnosis.Chi square test was performed for comparing the performance among different CNN.Furthermore,7 oral radiologists (including 2 seniors and 5 juniors) made a diagnosis on the 200 panoramic radiographs in the test set,and the diagnosis results were compared between CNN and oral radiologists. Results The eight neural network models showed the diagnostic accuracy ranging from 82.50% to 87.50%,of which EfficientNet b1 had the highest accuracy of 87.50%.There was no significant difference in the diagnostic accuracy among the CNN models (P=0.998,P=0.905).The average diagnostic accuracy of oral radiologists was (70.30±5.48)%,and there was no statistical difference in the accuracy between senior and junior oral radiologists (P=0.883).The diagnostic accuracy of CNN models was higher than that of oral radiologists (P<0.001). Conclusion Deep learning CNN can realize accurate differential diagnosis between ameloblastoma and odontogenic keratocyst with panoramic radiographs,with higher diagnostic accuracy than oral radiologists.
Humans ; Ameloblastoma/diagnostic imaging* ; Deep Learning ; Diagnosis, Differential ; Radiography, Panoramic ; Retrospective Studies ; Odontogenic Cysts/diagnostic imaging* ; Odontogenic Tumors

Oral lichen planus (OLP) is a chronic and inflammatory oral mucosal disease that commonly affects middle-aged females. Most OLP cases might exhibit such symptom as pain, roughness and other discomfort, and more severe forms may show a high risk of developing oral cancer. Active preventive measure, precise diagnosis and standard therapeutic approach play a vital role in the management and prevention of OLP. This guideline is a revision on the base of trial in 2012, which mainly covers the following 8 aspects: etiology and medical records, clinical manifestations, pathological manifestations, diagnosis, differential diagnosis, laboratory examination, disease treatment and prevention, aiming at providing scientific evidence and guidance for the dental clinicians in diagnose and treatment of OLP.
Diagnosis, Differential ; Female ; Humans ; Lichen Planus, Oral/therapy* ; Middle Aged ; Mouth Neoplasms

ABSTRACT Dental anomalies may occur due to the complex interactions among genetic, epigenetic, and environmental factors during dental development. The current study aimed to determine the prevalence and gender significance of developmental dental anomalies (DDA) in dental patients. This was a cross-sectional study of 260 subjects (123 males and 137 females) with an age range of 6–35 years old. Clinical and radiographic examinations were performed to determine the prevalence of anomalies in tooth number, shape, size, position, and structure. Descriptive statistics was performed, the chi-square test was used for analysis and p-value was set at 0.05. The findings showed that 203 subjects (78.1%) had DDA, which included 86 males (33.1%) and 117 females (45%). A significant gender difference was found regarding the prevalence of two anomalies (p < 0.05). The most prevalent anomaly was displacement 51.2%, followed by dilaceration 24.2%. A significant gender difference (p < 0.05) was found regarding hypodontia 16.5% and impaction 14.6%, with more predominant in females. Some anomalies were not observed such as microdontia, dentin dysplasia, ectopic eruption, gemination, and taurodontism. The study concluded that displacement and dilacerations were the common abnormalities. These findings may lead to various dental complications. Therefore, early diagnosis and follow-up observation are required to reduce the potential dental problems. In addition, it is helpful to increase the knowledge of practitioners with regards to DDA and its occurrence. Furthermore, it is good to highlight the importance of early diagnosis of DDA, especially in the mixed dentition, which can lead to reducing the complication of an orthodontic treatment plan.
Tooth Abnormalities ; Radiography, Dental, Digital ; Libya

ABSTRACT This study evaluated the cytotoxicity of four bioceramic root canal sealers (bioceramic sealers): GuttaFlow Bioseal (GB), MTA Fillapex, CeraSeal Bioceramic root canal sealer (CS), and iRoot SP root canal sealer (iRSP). The viability of human gingival fibroblast (HGF) cells was used to evaluate the cytotoxicity of these bioceramic sealers. HGF cells were cultured and exposed to bioceramic sealer extracts for 24 hours, 48 hours and 72 hours at 37°C in an incubator humidified with 5% CO2. The 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide or MTT assay was conducted to determine cell viability at each incubation period and compared among all bioceramic sealers. The Kruskal-Wallis test revealed statistically significant differences between the positive control group and MTA Fillapex, MTA Fillapex and GB, and between GB and iRSP with p < 0.05. However, no statistical differences were found in cell viability for each material across all the incubation periods. GB was the least cytotoxic bioceramic sealer with cell viability exceeding 90% throughout the 72-hour incubation followed by CS, iRSP, and MTA Fillapex with non-cytotoxicity after 72-hour incubation, mild cytotoxicity after 72-hour incubation, and mild cytotoxicity after 72-hour incubation, respectively. However, iRSP showed moderate cytotoxicity, and MTA Fillapex was severely cytotoxic (< 30% cell viability) after 24-hour incubation.
Root Cause Analysis ; Dental Pulp Test

During the automatic reconstruction of panoramic images, the effect of dental arch curve fitting will affect the integrity of the content of the panoramic image. Metal implants in the patient's mouth usually lead to a decrease in the contrast of the panoramic image, which affects the doctor's diagnosis. In this paper, an automatic oral panoramic image reconstruction method was proposed. By calculating key image areas and image extraction fusion algorithms, the dental arch curve could be automatically detected and adjusted on a small number of images, and the intensity distribution of teeth, bone tissue and metal implants on the image could be adjusted to reduce the impact of metal on other tissues, to generate high-quality panoramic images. The method was tested on 50 cases of cone beam computed tomography (CBCT) data with good results, which can effectively improve the quality of panoramic images.
Humans ; Radiography, Panoramic/methods* ; Cone-Beam Computed Tomography/methods* ; Tooth ; Algorithms ; Image Processing, Computer-Assisted/methods*

OBJECTIVE: To evaluate the clinical effect of root canal obturation therapy using cold flowable gutta-percha on young permanent teeth after apexification. METHODS: Ninety cases of young permanent teeth with pulp necrosis or periapical periodontitis treated by apexification were randomly divided into two groups. The cases in each group were divided into single root canal and multiple root canal according to the number of the root canal, and divided into classifications Ⅰ, and Ⅱ/Ⅲ/Ⅳ according to Frank's classification of root development after apexification. Cold flowable gutta-percha and warm gutta-percha obturation techniques were used for root canal obturation of the two groups. The operation time was recorded, and the patients' therapy pain degree was evaluated by visual analog scale (VAS) immediately after operation. Periapical X-ray was performed after operation to evaluate the effect of the root canal filling. The total length of the root was divided into equal three parts on the X-ray film, and three-dimensional tightness of the apical, middle, and coronal region of the root canals were statistically analyzed respectively. Clinical examinations and X-ray examination were performed 6 and 12 months after the operation to evaluate the treatment success rate. RESULTS: The operation time of cold flowable gutta-percha group was significantly lower than that of the control group, which were 51 s and 74 s (P < 0.05); The percentages of pain and discomfort in the two groups were 26.67% and 40.00%, respectively. There were two cases of underfilling and no overfilling in both groups. The percentages of proper filling and tight three-dimensional obturation in the experimental and control groups were 71.11% and 60.00% respectively; and the percentages of tight three-dimensional obturation in the apical third areas were 86.67% and 66.67%, the difference was significant (P < 0.05). There was no significant difference in the three-dimensional tightness between the two groups in the middle and coronal third areas. The percentages of tight three-dimensional obturation in classification Ⅰ groups were 86.67%, 83.33%, 93.33% and 76.67%, 90.00%, 96.67% in experimental and control group, respectively; The percentages of classification Ⅱ/Ⅲ/Ⅳ groups were 86.67%, 86.67%, 100.00% and 46.67%, 86.67%, 100.00%, respectively, and the difference was significant (P < 0.05). There were no apical lesions that occurred in either group during the one-year review period. CONCLUSION The application of cold flowable gutta-percha on young permanent teeth root canal obturation after apexification can achieve good obturation effect. The root obturation effect in the apical third area is significantly better than that of warm gutta-percha obturation techniques. Cold flowable gutta-percha can shorten the clinical treatment time and ameliorate the patients' therapy comfort.
Apexification ; Dental Pulp Cavity ; Gutta-Percha ; Humans ; Radiography ; Root Canal Filling Materials ; Root Canal Obturation ; Root Canal Preparation

Report of the fourth national oral health survey showed that the prevalence of gingivitis and periodontitis stayed at a high level in Chinese population and the periodontitis was the most common cause of tooth loss in Chinese adults. Therefore, the examination of periodontal health status, disease condition and risk assessment are particularly important. The Society of Periodontology of the Chinese Stomatological Association organized experts of related disciplines to formulate the standard of basic periodontal examination and evaluation during oral diagnosis and treatment, aiming to emphasize the necessity and importance of periodontal health and to improve dental clinicians' abilities in understanding, diagnosis and treatment planning of periodontal disease. As a national and professional standard, it will play an important and practically significant role in conservation of natural teeth and improvement of people's oral health in China.
Adult ; China ; Diagnosis, Oral ; Gingivitis ; Humans ; Periodontal Diseases/therapy* ; Reference Standards

Objective To study the accuracy of Nolla method for age estimation of Northern Chinese Han children aged between 5.00 and 14.99 years based on original transformation tables and multiple regression model. Methods A total of 2 000 orthopantomographs （OPGs） were collected from the Hospital of Stomatology, Xi'an Jiaotong University, including 1 000 males and 1 000 females. Development stage of 7 left mandibular permanent teeth （except third molars） was assessed based on Nolla method, then age estimation was conducted through transformation tables and multiple regression model, respectively. Firstly, the development stage results of 7 permanent teeth were added up and the estimated age was obtained through the original transformation tables. Secondly, 80% of the samples （80 males and 80 females in each age group） were randomly selected from 2 000 OPGs as the train set. The chronological age of the selected patients was taken as the dependent variable, while gender and the development stage results of 7 permanent teeth were taken as the independent variable to establish multiple regression model. The remaining 20% of the samples were substituted into the model as the test set, to verify the accuracy of age estimation by multiple regression model. Results Mean chronological ages of males and females were 10.03±0.09 years and 10.01±0.09 years, respectively. The age estimated by original transformation tables showed an overestimation for males （0.18 years on average） and an underestimation for females （0.02 years on average）, with mean absolute error （MAE） of 0.94 years and 0.97 years, respectively. While the results by multiple regression model showed that males were overestimated by 0.06 years on average and females were underestimated by 0.02 years on average. The MAE was 0.66 years and 0.77 years, respectively. Conclusion The Nolla method is suitable for age estimation of Northern Chinese Han children. Compared with the original transformation tables method, the multiple regression model is more accurate for age estimation.
Adolescent ; Age Determination by Teeth ; Asian People ; Child ; Child, Preschool ; China ; Female ; Humans ; Male ; Molar, Third ; Radiography, Panoramic

Background: Oral lichen planus is an idiopathic autoimmune inflammatory condition and oral lichenoid reactions are lesions that resemble oral lichen planus clinically and histopathologically, but develop secondary to various underlying causes. Oral lichenoid reactions have been reported to be caused by contact allergy to dental materials. This study aims to describe the characteristics of patients with a clinical and/or histopathological diagnosis of oral lichen planus who underwent patch testing in Hospital Kuala Lumpur, Malaysia. Methods: This is a 5-year retrospective study of patients who had oral lichen planus and had undergone patch testing at the Department of Dermatology, Hospital Kuala Lumpur, Malaysia between January 2015 and Cecember 2019. Patch tests were performed with European Baseline Series and relevant extended series, which include dental and metal series as well as patients’ own products. Patch test results were recorded according to the International Contact Dermatitis Research Group recommendation. Results: There were 41 patients with oral lichen planus who underwent patch test. The median age was 56 (range 21 to 73) with 70.7% of patients being female. There were 29 (70.7%) patients who developed at least one positive reaction. The most frequent sensitizing allergens were nickel sulfate (34.1%), gold(I)sodium thiosulphate dihydrate (22.0%), fragrance mix I (19.5%), cobalt chloride (14.6%), Peru balsam (12.2%) and sodium tetrachloropalladate (II) hydrate (12.2%). Current relevance was recorded in 16 patients (39.0%) and of these patients, 12 of them had positive patch test reactions to allergens found in dental materials such as dental fillings, dental implants, orthodontic braces, dentures and dental crowns. Conclusion Contact sensitization was detected in about 70% of our patients with oral lichen planus. The most common sensitizing allergen was nickel sulfate. Current relevance was found mainly towards dental materials.
Lichen Planus, Oral--diagnosis ; Dermatitis, Allergic Contact ; Department of Dermatology, Hospital Kuala Lumpur (Malaysia)