RadImageNet and ImageNet as Datasets for Transfer Learning in the Assessment of Dental Radiographs: A Comparative Study.

Transfer learning (TL) is an alternative approach to the full training of deep learning (DL) models from scratch and can transfer knowledge gained from large-scale data to solve different problems. ImageNet, which is a publicly available large-scale dataset, is a commonly used dataset for TL-based image analysis; many studies have applied pre-trained models from ImageNet to clinical prediction tasks and have reported promising results. However, some have questioned the effectiveness of using ImageNet, which consists solely of natural images, for medical image analysis. The aim of this study was to evaluate whether pre-trained models using RadImageNet, which is a large-scale medical image dataset, could achieve superior performance in classification tasks in dental imaging modalities compared with ImageNet pre-trained models. To evaluate the classification performance of RadImageNet and ImageNet pre-trained models for TL, two dental imaging datasets were used. The tasks were (1) classifying the presence or absence of supernumerary teeth from a dataset of panoramic radiographs and (2) classifying sex from a dataset of lateral cephalometric radiographs. Performance was evaluated by comparing the area under the curve (AUC). On the panoramic radiograph dataset, the RadImageNet models gave average AUCs of 0.68 ± 0.15 (p < 0.01), and the ImageNet models had values of 0.74 ± 0.19. In contrast, on the lateral cephalometric dataset, the RadImageNet models demonstrated average AUCs of 0.76 ± 0.09, and the ImageNet models achieved values of 0.75 ± 0.17. The difference in performance between RadImageNet and ImageNet models in TL depends on the dental image dataset used.

Dental Abnormalities in Pediatric Patients Receiving Chemotherapy.

Background: Chemotherapy is a common treatment for pediatric cancer. Although life prognosis is improving because of advances in medical science, it is important to deal with late effects such as dental abnormalities. We investigated the association between dental abnormalities and chemotherapy by age and tooth type. Methods: Among the 568 patients referred to the pediatric dentistry department of our hospital, we selected 32 patients (21 male and 11 female) who received chemotherapy between the ages of 0 and 6 and underwent panoramic examination after the age of 7. We recorded the age of chemotherapy commencement, diagnosis of systemic disease, and dental abnormalities such as congenital absence, microdonts, and short-rooted teeth. Results: Almost half of the patients had dental abnormalities such as congenital absence, microdonts, and short-rooted teeth, but there were no significant differences in the incidence of these abnormalities by age. When we analyzed the incidence of abnormal teeth by tooth type, the incidence of congenital absence was significantly higher in premolars (5.5%) and second molars (3.9%) than in incisor or canine or 1st molar (0.4%) (p < 0.01). The incidence of microdonts was significantly higher in premolars (3.9%) than in incisor or canine or 1st molar (0.2%) and second molars (0.0%) (p < 0.05). Conclusions: Patients who received chemotherapy had a high prevalence of dental abnormalities, and the incidence of abnormalities varied by tooth type. It is important to maintain long-term oral care for patients who have undergone chemotherapy even after the treatment is completed.

Five-Year Follow-Up of a Child with Non-Syndromic Oligodontia from before the Primary Dentition Stage: A Case Report.

BACKGROUND: Congenital absence of teeth is a major dental abnormality in pediatric dentistry and the absence of six or more teeth is defined as oligodontia. Few reports of patients with non-syndromic oligodontia without systemic disease have continued dental follow-up from an early age. METHODS: We performed the five-year follow-up from before the eruption of the primary dentition of a Japanese child with non-syndromic oligodontia and analyzed changes in dental arch growth. RESULTS: At the oral examination at the age of 1 year and 2 months, eight primary incisors were congenitally absent. Therefore, we made dentures for the patient at the age of 3 years and 4 months. From the age of 5 years and 1 month, the child received articulation training for dysarthria from a speech therapist to improve the function and appearance of the oral cavity. Measurement of the patient's dental models revealed a particularly narrow dental arch, especially between the primary canines. CONCLUSIONS: Our findings highlight the importance of treatment for patients with non-syndromic oligodontia from an early age by multiple medical professionals, recognizing that the missing teeth affect the growth of the maxillofacial region.

A Third Supernumerary Tooth Occurring in the Same Region: A Case Report.

The presence of a supernumerary tooth is one of the most common dental anomalies, and surgical treatment is often required to address this anomaly. Moreover, it may lead to malocclusion, and long-term follow-up is important to monitor its status. A 4-year-and-11-month-old boy was referred to our hospital for dental caries treatment. At 5 years and 5 months of age, a radiographic examination showed a supernumerary tooth (first supernumerary tooth) near the permanent maxillary left central incisor, and it was extracted 6 months later. Eighteen months after the extraction of the first supernumerary tooth, a new supernumerary tooth (second supernumerary tooth) was detected in the same region, which was extracted when the patient was aged seven years and seven months. Seven months later, another supernumerary tooth (third supernumerary tooth) was detected and extracted immediately. However, the permanent maxillary left central incisor did not erupt spontaneously even after 6 months. Therefore, surgical exposure was performed, and the central incisor erupted into the oral cavity. This report describes our experience with this patient with three metachronous supernumerary teeth and their management until the eruption of the permanent tooth. This report highlights the importance of long-term follow-up after supernumerary tooth extraction until the permanent teeth in that region have erupted completely.

Analysis of the feasibility of using deep learning for multiclass classification of dental anomalies on panoramic radiographs.

The aim of the feasibility study was to construct deep learning models for the classification of multiple dental anomalies in panoramic radiographs. Panoramic radiographs with single supernumerary teeth and/or odontomas were considered the "case" group; panoramic radiographs with no dental anomalies were considered the "control" group. The dataset comprised 150 panoramic radiographs: 50 each of no dental anomalies, single supernumerary teeth, and odontomas. To classify the panoramic radiographs into case and control categories, we employed AlexNet, which is a convolutional neural network model. AlexNet was able to classify whole panoramic radiographs into two or three classes, according to the presence or absence of supernumerary teeth or odontomas. The performance metrics of the three-class classification were 70%, 70.8%, 70%, and 69.7% for accuracy, precision, sensitivity, and F1 score, respectively, in the macro average. These results support the feasibility of using deep learning to detect multiple dental anomalies in panoramic radiographs.

Three-year survey of oral hygiene conditions of Cambodian public primary school children.

PURPOSE: The purpose of this repeated cross-sectional study was to investigate the prevalence and severity of oral hygiene conditions in Cambodian primary school children. METHODS: Oral examinations were conducted on 2,020 school children (1st-6th grade) at a public primary school in Siem Reap, Cambodia from 2013 to 2015, focusing on plaque adhesion, gingiva, and dental calculus deposition. Data analysis was performed on 1,998 children without any missing data, and the chi-square test was used to compare the variables. RESULTS: The prevalence of dental plaque adhesion in 2013, 2014, and 2015 was 93.6%, 93.7%, and 85.1%, respectively. The prevalence of gingivitis in 2013, 2014, and 2015 was 93.1%, 92.1%, and 88.8%, respectively. The prevalence of dental calculus deposition in 2013, 2014, and 2015 was 55.1%, 19.3%, and 34.7%, respectively. Significant differences were observed in all variables each year (P < 0.001). CONCLUSION: The findings of this study suggest that oral hygiene conditions were poor in this population.

Detecting the presence of supernumerary teeth during the early mixed dentition stage using deep learning algorithms: A pilot study.

BACKGROUND: Supernumerary teeth are a common anomaly and are frequently observed in paediatric patients. To prevent or minimize complications, early diagnosis and treatment is ideal in children with supernumerary teeth. AIM: This study aimed to apply convolutional neural network (CNN)-based deep learning to detect the presence of supernumerary teeth in children during the early mixed dentition stage. DESIGN: Three CNN models, AlexNet, VGG16-TL, and InceptionV3-TL, were employed in this study. A total of 220 panoramic radiographs (from children aged 6 years 0 months to 9 years 6 months) including supernumerary teeth (cases, n = 120) or no anomalies (controls, n = 100) were retrospectively analyzed. The CNN performances were assessed according to accuracy, sensitivity, specificity, receiver operating characteristic (ROC) curves, and area under the ROC curves for a cross-validation test dataset. RESULTS: The VGG16-TL model had the highest performance according to accuracy, sensitivity, specificity, and area under the ROC curve, but the other models had similar performance. CONCLUSION: CNN-based deep learning is a promising approach for detecting the presence of supernumerary teeth during the early mixed dentition stage.

Significant increase of oral bacteria in the early pregnancy period in Japanese women.

AIM: Oral microflora during pregnancy is critical to oral health care in the mother and her child. We examined the changes in the oral microbiota between pregnancy and nonpregnancy periods. METHODS: The study was performed using 132 healthy pregnant women enrolled from Hiroshima City Asa Citizens Hospital and 51 healthy nonpregnant women as control. During pregnancy, 132 subjects were assessed for seven microbial species by the cultured method and polymerase chain reaction at the early (7-16 weeks gestation), the middle (17-28 weeks), and the late (29-39 weeks) pregnancy periods. Pregnant women completed a series of questionnaires regarding oral and systemic health and lifestyle habits. RESULTS: The total cultivable microbial counts in the early pregnancy were significantly higher than that of the nonpregnant women (P < 0.05). The incidences of Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans in gingival sulcus during the early and middle pregnancy were significantly higher than the nonpregnant group (P < 0.05), while Prevotella intermedia and Fusobacterium nucleatum did not change. Candida species were more frequently detected during the middle and late pregnancy. CONCLUSION: The data suggest that pregnancy, especially in the early periods, promotes the proliferation of microorganisms in the oral cavity and facilitates a colonization of periodontal pathogens.

Four New Sesquiterpenoids from Ligularia subspicata Collected in China; Isolation of a Bakkane-type Lactone, an Eremophilane-type Lactone, and Two Ortho Esters.

A bakkane type lactone, an eremophilane type lactone, and two ortho esters were isolated from Ligularia subspicata collected in Sichuan Province, China. The ortho ester type compound has been isolated from Ligularia for the first time.

Water-soluble fullerene materials for bioapplications: photoinduced reactive oxygen species generation.

The photoinduced reactive oxygen species (ROS) generation from several water-soluble fullerenes was examined. Macromolecular or small molecular water-soluble fullerene complexes/derivatives were prepared and their (1)O(2) and O(2)˙(-) generation abilities were evaluated by ESR spin-trapping methods. As a result, efficient (1)O(2) generation was detected from photoexcited C(60), not only in organic solvents, but also in aqueous media and especially from small molecule C(60)-carboxylic acid derivatives. Whereas efficient O(2)˙(-) generation was observed in the aqueous solution of the C(60)/γ-CD complex under photoirradiation.

Germacranolides and their diversity of Eupatorium heterophyllum collected in P. R. China.

Eight new hydroperoxides and a new enone of germacrane-type sesquiterpenoids were isolated from the aerial parts of eight different samples of Eupatorium heterophyllum DC. (Asteraceae) collected in P. R. China. The structures were determined based on spectroscopic analyses. Seven of the eight samples produced hiyodorilactone A as a major constituent, while one afforded neither hiyodorilactone nor hydroperoxide. The results indicated the presence of diversity within this species.

Effects of emotional music on visual processes in inferior temporal area.

To investigate the effects of emotional music on visual processes, we analyzed visual evoked magnetic fields (VEF) on listening to emotional music in 14 healthy subjects. Positive and negative pieces of music were delivered during VEF recording following stimulation by emotionally neutral pictures of faces and landscapes. VEF components at 100 (M100) and 150 (M170)ms after stimulus onset were analyzed, and the estimated current strength for M170 following face stimulation was enhanced with negative compared to positive music in the right hemisphere. The equivalent current dipole for M100 and M170 was estimated in the primary visual cortex (V1) and inferior temporal area (IT), respectively. The present results indicate that background music showed a top-down control of the visual processes in IT, which is a core site responsible for the interpretation of facial expression. The emotional contents of music could alter visual processes, especially those involving the face.

Water-soluble C60- and C70-PVP polymers for biomaterials with efficient (1)O2 generation.

Highly water-soluble fullerene polymers were successfully prepared by a simple direct free-radical copolymerization of N-vinylpyrrolidone and intact C60 or C70 as a radical-capping agent. Using AIBN as a radical initiator, the polymers (C60- or C70-PVP) with significantly high molecular weight (~30 kDa) and with efficient (1)O2 generation were obtained.

Four new guaianolides and acetylenic alcohol from Saussurea katochaete collected in China.

Four new guaianolides and an acetylenic alcohol were isolated from Saussurea katochaete (Asteraceae) collected in China. The structures were determined based on the spectroscopic data including the absolute configuration by application of advanced Mosher's method.

Alteration of time perception in young and elderly people during jigsaw puzzle tasks with different complexities.

We investigated the relationship between time perception during tasks and subjective feelings in young and elderly people. Simple and complex jigsaw puzzles were given to healthy young and elderly subjects. The subjects were asked to estimate the time they had taken to complete the tasks after performing them. The ratio of the subjective to actual duration of time, the duration judgment ratio (DJR), and the relationship between the DJR and the subjective feelings during the tasks were analysed. The elderly group required a significantly longer time than the younger group for both tasks, and both elderly and young subjects estimated a longer time than the actual time to complete the tasks. The effect of the tasks on the DJR was significant, and the value was higher for the 24-piece than 54-piece task in both groups. The DJR was smaller in subjects with "much interest" than in those with "little interest" in the 24-piece task, but there was no difference in the 54-piece task. The results indicate that time perception was modulated by subjective feelings during the task, as well as by the age and task complexity. Because the goal and the result of the task may modulate time perception during it, time perception while actually performing the task may differ from that after completing it.

Regulatory mechanism for exfoliative toxin production in Staphylococcus aureus.

The exfoliative toxin (ET) is a major virulence factor of Staphylococcus aureus that causes bullous impetigo and its disseminated form, staphylococcal scalded-skin syndrome (SSSS). ET selectively digests one of the intracellular adhesion molecules, desmoglein 1, of epidermal keratinocytes and causes blisters due to intraepidermal cell-cell dissociation. Most S. aureus strains that cause blistering disease produce either ETA or ETB. They are serologically distinct molecules, where ETA is encoded on a phage genome and ETB is enocded on a large plasmid. ETA-producing S. aureus strains are frequently isolated from impetigo patients, and ETB-producing S. aureus strains are isolated from SSSS. ET-induced blister formation can be reproduced with the neonatal mouse. To determine the regulatory mechanism of ET production, we investigated the role of the two-component systems and global regulators for eta or etb expression in vitro and in vivo with the mouse model. Western blot and transcription analyses using a series of mutants demonstrate ETA production was downregulated by sigB, sarS, and sarA, while ETB production was downregulated by sigB and sarA but not by sarS. Production of both toxins is upregulated by saeRS, arlRS, and agrCA. Furthermore, by the in vivo neonatal mouse model, sigB and sarS but not sarA negatively regulate the exfoliation activity of the ETA-producing strain, while sarA negatively regulates the ETB-producing strain. In both strains, saeRS, arlRS, and agrCA positively regulate the exfoliation activity in vivo. The data illustrate similar but distinct regulatory mechanisms for ETA and ETB production in S. aureus in vitro as well as in vivo.

A highly water-soluble C60-NVP copolymer: a potential material for photodynamic therapy.

Water-soluble C60 polymers, which have the highest solubility of fullerene reported to date (7.8 mM of C60 in water), were prepared via copolymerization, and showed significant visible light-induced O2*- generation and DNA cleavage, indicating the potential of these water-soluble fullerene derivatives as agents for photodynamic therapy.

Stimulating the production of homoisoflavonoids in cell suspension cultures of Caesalpinia pulcherrima using cork tissue.

It has previously been demonstrated that cork tissue increases the efficiency of the production of lipophilic secondary metabolites in diverse plant cell suspension cultures. In the present study, three new homoisoflavonoids--named dihydrobonducellin, 2'-methoxydihydrobonducellin, and 2'-methoxybonducellin--and bonducellin and isobonducellin were isolated from Caesalpinia pulcherrima cultured cells coincubated with cork tissue. Cork tissue increased the production of 2'-methoxybonducellin by about 7-fold relative to control cells, and more than 80% of the product was recoverable from the cork tissue. When cork tissue and methyl jasmonate or yeast extract were added simultaneously to the medium, the amount of 2'-methoxybonducellin produced increased further. The production of the other four homoisoflavonoids was enhanced by variable amounts. Our results indicate that the addition of cork tissue would be an effective technique for investigating formation of secondary metabolites that usually accumulate only in trace amounts.