We evaluated early caries activity and risk assessment using the International Caries Detection and Assessment System (ICDAS). The tooth surfaces of 31 nursery school children (3.7±0.7 years of age) were examined. We examined all surfaces except the interproximal, and followed the changes in the caries code every 6 months for 18 months. There was no statistical difference between the ICDAS activity code and changes in early carious lesions. Therefore, it was difficult to predict the progress and recovery of early carious lesions from the ICDAS activity code. However, it was suggested that the risk of early caries on sound surfaces could be determined by observing a history of the ICDAS caries code over time. (J Osaka Dent Univ 2021; 55: 1-7)

Bimaxillary protrusion, which causes facial disharmony due to protrusion and incomplete closure of the lips, has many psychological effects on the patient. We investigated whether changes in soft tissue morphology could be predicted by using the revised analysis method proposed by Arnett to determine the relationship between changes in hard tissue morphology and changes in the soft tissue profile before and after orthodontic treatment of adult patients with bimaxillary protrusion. The subjects were 30 patients who were diagnosed as having bimaxillary protrusion. We measured each item of the STCA to determine the amount of change in soft tissue using cephalograms before and after treatment, and examined the correlation between changes in the hard and soft tissues. We found some correlations between soft and hard tissue changes in the items of dentoskeletal factors, facial length, and projection TVL. These results suggest that it is necessary to understand the relationship between changes in the hard and soft tissues before and after orthodontic treatment. (J Osaka Dent Univ 2021; 55: 9-20)

Although wearing surgical masks likely reduces the transmission of respiratory infections, other mask types may be used when they are in short supply. A previous study showed that surgical masks were three times more effective than homemade masks at blocking transmission due to their fit. Therefore, we designed a custom-made cloth face mask assisted by a CAD/CAM system to achieve an improved fit of cloth masks. One 38-year-old male participant scanned his own face using a 3D selfie app and imported the data into CAD software to design a mask frame. This was printed in dental photocurable resin using a 3D printer and completed within 3 hours. Paper towels can be attached to the frame with glue or the frame can be used to cover a handkerchief. The custom-made mask has a proper fit to cover the nose and oral cavity and can be an alternative option during a surgical mask shortage. (J Osaka Dent Univ 2021; 55: 21-25)

We investigated the morphological influence of bisphosphonates on the rat maxillary gingiva using an ovariectomized osteoporosis model rat. Eight-week-old female Wistar rats were divided into osteoporosis and sham surgery groups; both groups underwent bilateral ovariectomy and laparotomy. After surgery, they were separated into either bisphosphonate or normal saline treatment groups. One week after completing treatment, all rats were euthanized, and the maxilla and mucosa were removed. No differences existed among the groups in the thickness of the mucosal epithelium or cell population in the granular and prickle layers. On the other hand, the cross-sectional area of the connective tissue beneath the mucosal epithelium and the diameter of the gingival capillaries were significantly smaller in the bisphosphonate groups than in the normal saline groups. The morphology of the microvascular network was regular and rectangular in the normal saline groups, but irregular and elliptical in the bisphosphonate groups. Although osteoporosis alone had no affect on the maxillary gingiva or microvascular architecture, bisphosphonate potentially caused microangiopathy and atrophic changes in this tissue. Thus, it is important to consider the morphological influence of bisphosphonate on tissues beneath the gingival mucosa and on the gingival microvascular architecture. (J Osaka Dent Univ 2021; 55: 27-33)

We examined the effect of non-lethal remote ischemic preconditioning (RIPC) on central nervous system regeneration. CB17 mice were divided into 3 treatment groups. The femoral artery (FA) group had temporary occlusion of the bilateral femoral arteries, the middle cerebral artery (MCA) group had temporary occlusion of left middle cerebral artery, and the carotid artery (CA) group had temporary occlusion of left carotid artery. Following the treatment, the expression of neural stem cells was examined by immunohistochemistry. In the FA and CA groups, nestin-positive neural stem cells were found primarily in the granular layer of the hippocampal dentate gyrus (DG), which is a known site of regeneration. Glial fibrillary acidic protein (GFAP)-positive astrocytes were also observed, and a subset of GFAP-positive cells also stained positive for nestin. These findings suggest that RIPC induces endogenous neural stem cells in the hippocampal DG. Double staining further suggested the presence of astrocytes that are reactive to tissue damage. Thus, neural stem cells may be involved in regulating resistance to ischemia, and astroglia may be involved in regeneration of the nervous system. (J Osaka Dent Univ 2021; 55: 35-40)

We calculated the geographic accessibility of dental clinics in Japan for each prefecture from 2010 to 2020 and examined the correlation between accessibility and dental consultation rate to evaluate the balance of supply and demand for dental services. As an index of accessibility to dental care, we calculated the accessibility index (AI) and the accessibility index rate (AIR) for the population outside a 1,000 meter radius using the geographic information system (GIS). We found that although there were no significant changes in the AI and AIR values during the 10 years from 2010, considerable differences existed among the prefectures. Moreover, multiple regression analysis revealed significant negative correlation between AIR and dental consultations among those over 75 years of age. Based on the above results, we concluded that in order to analyze the supply and demand for dental services, it is necessary to reduce the service area. In addition, there is need to analyze the supply and demand for dental care considering the geographic accessibility of those over 75 years of age. (J Osaka Dent Univ 2021; 55: 41-46)

Support for intraoral and panoramic imaging is one of the most important roles of dental hygienists in dental practice. Understanding the anatomy of intraoral and panoramic images is also essential for correct imaging assistance and for gathering information for scaling and root planning in oral health care. To date, few studies have evaluated the practical training of oral radiology for dental hygiene students. In this study, the knowledge of intraoral imaging, panoramic imaging, and imaging anatomy for intraoral and panoramic imaging, which is required for dental hygiene students, was evaluated in second-year students. In addition, to evaluate the performance of dental hygiene students in the practical training of dental radiology and imaging anatomy of the maxillofacial region, questionnaires were conducted and subjectively evaluated by the students.They rated the practical training more highly than the lectures for all items except "Did it help you understand imaging anatomy?" The results of this study suggest that dental hygiene students consider practical training superior to lectures. (J Osaka Dent Univ 2021; 55: 47-52)

When our artificially synthesized peptide (ASPep) with a scaffold that provides extended release was cutaneously placed in rats, it induced hard tissue formation. We focused on synthetic calcium particles (SCPs) made of calcium phosphate-coated calcium carbonate to develop a better scaffold. We performed three different experiments to investigate the properties of SCPs. We observed the surface of SCPs by scanning electron microscope (SEM); following saturation in albumin the amount of the albumin released from the SCPs was measured in vitro after they were saturated in albumin; and we observed the biological reaction to SCPs saturated in ASPep using a monoclonal antibody to ASPep (MoAb Pep) in vivo. The SEM findings indicated that the surface of the SCPs was porous. In an in vitro study, the concentration of albumin gradually increased following elution from the SCPs. In another in vivo study, the immuno reaction to the MoAb ASPep was localized in the central region of the SCP at 14 days, wherereas that reaction in the outer region of the SCP had disappeared. It is suggested that the ASPep in the SCPs was eluted from the surface layer of the SCPs by day 7, while that in the central region remained longer and was more slowly released. (J Osaka Dent Univ 2021; 55: 53-58)

Tumor progression and metastasis are caused by various mechanisms such as epithelial-mesenchymal transition (EMT) or escape from the host immune surveillance using PD1/PD-L1 signaling. Furthermore, hepatocyte growth factor (HGF) induces EMT in many types of cancers, and the analysis of the HGF/c-Met pathway is progressing. In this study, we investigated the relationship between the expression of c-Met and PD-L1 using oral squamous cell carcinoma (OSCC). A poorly-differentiated OSCC shows strong c-Met and PD-L1 strong staining in the invasion front of tumor nests. A well-differentiated OSCC shows c-Met and PD-L1 staining in the nuclei of some tumor cells. The peripheral cells of the cancer pearl are stained more densely than the central tumor cells. c-Met and PD-L1 protein expression levels were higher in poorly differentiated OSCC than in those of well-differentiated OSCC (p<0.01). The positive rate of both c-Met and PD-L1 tended to correlate with the degree of differentiation. Furthermore, the expression of c-Met and PD-L1 were correlated and tend to be strongly expressed in the invasion front of tumor nests. These results suggest that c-Met and PD-L1 expression is associated with EMT and metastatic potential. (J Osaka Dent Univ 2021; 55: 59-64)

We examined the facial characteristics of Chinese children with maxillary protrusion using Steiner analysis. Fifty boys and 50 girls were selected from a clinic in Shanong, China, who were classified by Hellman's developmental stage IIIC and chronological age stage IV. Angular and linear measurements were determined. In comparison with pre-existing measurement values for Chinese, the ANB angle, U1 to NA (mm), U1 to NA (angle), Po to NB and ∠GoGn to SN values for the Chinese subjects were significantly larger for stage IIIC, while the SNB angle, SND angle, Interincisal angle, ∠Occl to SN, and SL values were significantly smaller. Compared to measurement values for Japanese, SNA angle, ANB angle, U1 to NA (mm), U1 to NA (angle), ∠GoGn to SN, and SE were larger, and the SNB angle, SND angle, L1 to NB (angle), Interincisal angle, ∠Occl to SN, and SL were smaller. These results demonstrate that the maxilla of Chinese in maxillary protrusion did not show overgrowth while the mandible showed undergrowth. Nevertheless, the clockwise rotation of the mandible of Chinese was smaller than that of Japanese. Based on the above findings, it was suggested that maxillary protrusion in Chinese is easier to treat than in Japanese. (J Osaka Dent Univ 2021; 55: 65-72)

MicroRNAs suppress the expression of target genes and extensively regulate the expression of genes involved in growth and disease. The purpose of this study was to detect exosomes from gingival crevicular fluid (GCF), and to elucidate disease-specific exosomal miRNA expression in GCF from patients with chronic periodontal disease. Comprehensive microRNA expression analysis was performed using exosomal miRNA in GCF to compare the GCF of patients with chronic periodontitis disease with that of healthy participants. The candidate exosomal miRNAs were analyzed using real-time quantitative polymerase chain reaction (qPCR). The presence of exosomes was observed by measuring the particle size, as well as by detecting CD9/CD63 and observing transmission electron microscope images (TEM). Eleven exosomal miRNAs were identified as differentially expressed more than 8 times lower than in healthy participants by global analysis. Of the miRNA, qPCR analysis revealed that the expression of hsa-mir-204-3p was lower in GCF collected from affected and unaffected sites of patients with chronic periodontal disease, compared with those collected from healthy individuals. This suggests that hsa-mir-204-3p might be associated with periodontal pathology. (J Osaka Dent Univ 2021; 55: 73-81)

The goal of dentistry is to prevent not only dental diseases but also systemic diseases by improving the oral environment. In this context, we focus on the improvement of oral microbiota. Various effects have been reported for propolis, a natural antimicrobial substance, which is used in health foods and folk medicines for periodontal diseases. We examined the effect of propolis on the oral microbiota using a next-generation sequencer. Gingival crevicular fluid was collected from periodontal pockets of more than 4 mm in three patients (two males and one female) at the Osaka Dental University Hospital, and the samples were cultured in SHI medium to obtain oral microbiota samples. Ethanol-extracted propolis (EEP; 0, 50 and 100 μg/mL; provided by Yamada Bee Farm, Okayama, Japan) was added to the samples and DNA was extracted after 24 h of incubation at 37°C with shaking under anaerobic conditions. Sequences of the V3-V4 region of the PCR-amplified 16S rRNA were decoded using the next-generation sequencer Miseq and changes in the microbiota after EEP treatment were analyzed. The effect of propolis on the growth of the periodontal bacteria Porphyromonas gingivalis (P. gingivalis) and Fusobacterium nucleatum (F. nucleatum) was then assessed by measuring the absorbance as optical density (OD) of liquid culture media and the colony forming units (CFUs) on solid media. EEP treatment did not show significant changes in the proportion and diversity of the cultured oral microbiota. However, EEP inhibited the growth of P. gingivalis in a dose-dependent manner, as evidenced in the experiments using OD measurements. In contrast, there was no significant effect on F. nucleatum proliferation. Furthermore, 100 μg/mL EEP reduced the number of P. gingivalis CFUs, but not that of F. nucleatum. These results suggest that EEP specifically inhibits the growth of the periodontal bacterium P. gingivalis without significantly altering the bacterial microbiota. (J Osaka Dent Univ 2021; 55: 83-89)

Matrix proteases are involved in the destruction and degeneration of articular cartilage, which is one of the pathological conditions of osteoarthritis of the temporomandibular joint (TMJOA). We investigated the expression of matrix proteases in combination with IL-1β and cyclic compression loading on three-dimensional (3D) cultured tissues of human articular chondrocytes. Human articular chondrocytes were seeded in atelocollagen sponge and cultured in 3D. Cyclic compressive loading of 40kPa at 0.5Hz was applied to the constructs for 1h, with or without the administration of IL-1β, which was added at concentrations of 0.1, 1 and 10ng/mL. After 6 or 12h of cyclic compression loading, the gene expression of the matrix proteases were evaluated by qRT-PCR. We found that cyclic compression loading significantly increased the expression of MMP-3, ADAMTS-4 and ADAM-17, while IL-1β stimulation significantly increased the expression of MMP-3, MMP-13, ADAMTS-4, ADAMTS-5 and ADAM-17. The expression of MMP-3 was synergistically upregulated by combining cyclic compressive loading with IL-1β when compared with a single stimulation. Therefore we believe that the application of our present biomechanical and biochemical model, which mimics the human intra-articular environment of OA, can facilitate elucidation of the mechanisms of articular cartilage degeneration and destruction in TMJOA. (J Osaka Dent Univ 2021; 55: 91-98)

Sagittal split ramus osteotomy (SSRO) is widely used as an excellent surgical technique with a wide range of indications for jaw deformities. However, regression after advancement of the mandible is considered problematic compared with that after setback. We constructed models of 5- and 10-mm advancement after SSRO, and performed mechanical analysis of changes over time in stress loading employing the 3-dimensional finite element method. Models of the mandible were prepared after SSRO using titanium plates and screws as osteosynthesis material after 5- and 10-mm advancement of the distal bone fragment. Occlusal force and the muscular strength of the closing muscles were applied to each model. The displacement was greater in the 10-mm model than in the 5-mm model with conventional and locking screw fixation, whereas it was smaller in the model with locking plate fixation than in that with conventional plate fixation. In addition, it was smaller in the model with 2-plate fixation than in the one with 1-plate fixation. 2-plate fixation with locking screws may be a useful bone fragment fixation method because the amount of advancement increases, leading to postoperative stability. (J Osaka Dent Univ 2021; 55: 99-111)

We investigated the correlation between two-dimensional (2D) panoramic imaging (PI) analysis and three-dimensional (3D) computed tomography (CT) analysis for evaluating the decompression of ameloblastoma (AME) and odontogenic keratocysts (OKC). Using each patient's individual data, we examined the correlation between decompression indices and patient characteristics to find correlations between the 2D and 3D evaluations, using the latter as the gold standard. We also evaluated the correlation between PI and CT analyses of lesion reduction and percent lesion reduction. The correlations were found between volume reduction and area reduction, as well as initial volume and initial area in both AME and OKC. Volume reduction rate and area reduction rate correlated with initial volume and initial area only for OKC. For AME, the regression equations were (volume reduction)=6.7+(area reduction)×0.7 and (percent volume reduction)=30.4+(percent area reduction)×0.6. Correlations were observed between the PI and CT evaluations and the utility of PI was verified for estimating lesion reduction from the initial size in AME and for lesion reduction and lesion reduction rate from the initial size in OKC. For AME, regression equations were obtained for estimating lesion reduction and percent lesion reduction on CT from PI. (J Osaka Dent Univ 2021; 55: 113-121)

The objective of this study was to clarify the influence of the half taper angle and thickness of the zirconia secondary crown on its fracture strength. Y-TZP was used for both primary and secondary crown. Samples were prepared at the half taper angles of 2° and 4° and a secondary crown thickness of 0.5 and 1.0 mm (n=7). The secondary crown was restored on the primary crown and the fracture strength was determined by loading all specimens until fracture using a universal testing machine. The load applied at the time of secondary crown fracture was regarded as fracture strength. Based on the analysis of variance, although the fracture strength at 1.0-mm thickness was significantly greater than that at 0.5-mm thickness, the taper angle had no influence on the fracture strength. (J Osaka Dent Univ 2021; 55: 123-128)

The diagnosis of lifestyle-related diseases and cancer at an early stage is important. The use of saliva, rather than blood testing, for diagnosis has many advantages, especially in terms of its non-invasiveness and convenience. We assessed expression levels of ERBB2, a cancer-related gene, and SIRT1, a gene associated with suppressing aging and improving immunity, using human saliva rather than blood samples. Fasting blood samples and unstimulated saliva samples from passive drooling were collected from healthy volunteers in their twenties, and the levels of markers within each sample were assessed via real-time polymerase chain reaction using the comparative threshold cycle (ΔΔCT) method. The nonparametric Mann-Whitney statistical test was applied to determine median differences. We used β-actin as the reference gene in this study. A significant difference and correlation between blood and saliva transcript levels of SIRT1 (r=0.344) were observed in the volunteers. Taken together, these findings indicate that the transcript levels of ERBB2 and SIRT1 measured from saliva have the capacity to be used as diagnostic biomarkers and may minimize the need for performing blood tests. (J Osaka Dent Univ 2021; 55: 129-136)

Although glass ionomer cement (GIC) has several favorable properties that may facilitate the management of deep carious lesions, some deficiencies still need to be overcome. Although cellulose nanofiber (CNF) is a plant-derived fiber material that has exhibited positive effects on the properties of GIC, there is lack of research on the addition of CNF to high-viscosity GIC. The objective of this study was to modify a conventional high-viscosity GIC restorative, Fuji IX GP-Ex^Ⓡ, with powdery CNF, and to evaluate its effect on the compressive strength (CS), flexural strength (FS), fracture toughness (FT), and fluoride release dose of the modified material during long-term aging. Samples were prepared by adding CNF (Cellulostar^Ⓡ) to the high-viscosity GIC at 0, 3, 4 and 5wt% and ageing it after mixing for up to 90 days in artificial saliva. The FS, FT and fluoride-ion release dose were significantly improved in the CNF modified GIC groups over time. However, no significant difference was observed in the CS. SEM observations showed that CNF has a high affinity for the GIC matrix, and that it aggregated and dispersed in the cured cement. Powdery CNF at approximately 4-5% is a promising reinforcement agent for conventional high-viscosity GIC. (J Osaka Dent Univ 2021; 55: 137-147)

The periodontal ligament has an important role in the homeostasis and regeneration of periodontal tissues. Ascorbic acid (AA) is a water soluble vitamin with various biological functions including osteoblastic differentiation. We investigated the effect of AA on periodontal ligament-derived fibroblasts (PDLF) using next generation sequencing, and examined the global gene expression profiles in PDLF with and without AA treatment using RNA sequencing and following pathway analysis. In differentially expressed gene analysis, we found 585 genes that were up-regulated by AA in PDLF and 651 that were down-regulated. Among them, 68 up-regulated genes and 75 down-regulated genes were considered statistically significantly different in AA-treated PDLF (PDLF-AA) compared with the control PDLF (PDLF-control). The MIR34A host gene (NR_132742) was the most up-regulated gene and FAM47E-STBD1 readthrough (NM_001242939) was the most down-regulated gene in PDLF-AA when compared with the PDLF-control. Some genes related to osteoblast differentiation were enhanced in PDLF-AA, including Indian hedgehog, alkaline phosphatase, and osteocalcin. KEGG enrichment analysis demonstrated that AA affected signaling pathways related to Hepatitis C, Influenza A, and transcriptional misregulation in cancer. These results suggest that AA treatment changes a wide variety of gene expressions in PDLF and can be considered new information useful for understanding the function of the periodontal ligament. (J Osaka Dent Univ 2021; 55: 149-157)

A recent study in Japan classified temporomandibular disorder (TMD) into four patterns. In this study, pain relief techniques using a mouthpiece were used to clarify the disappearance of TMD pain over time, and to examine their utility in preventive care dentistry as primary TMD treatments. We studied types I and II TMD in 50 patients who were examined at a dental clinic. We also analyzed occlusal balance using study models. Distances from the hamular notch-incisive papilla plane to numerous landmarks including teeth and bone, were measured based on myodontics theory, and numerous patterns of occlusal balance were characterized. In accordance with myodontics theory, TMD pain disappeared within a few weeks of using a mouthpiece. This disappearance, as well as decreases in clicking and crepitus, was confirmed by statistical analysis. These results can be applied to primary preventive dental health care. (J Osaka Dent Univ 2021; 55: 159-162)

Individuals encounter numerous scents in modern society, such as the scent of a fabric softener or aroma oil. Pregnant women often use aroma oils for their stress-relieving or relaxing effect. However, evidence regarding the negative effects of these scents on offspring is lacking. In this study, a wood-derived scent was exposed to pregnant rats, and the presence or absence of negative effects was investigated in the offspring. No clear effect was observed on bodyweight measured up to 43 days of age to confirm the effect on growth. In the open-field test, only gender difference was significant in locomotor activity and rearing behavior, with males being less active than females, and scent had no effect. Although grooming behavior showed a low score in the scent group, the difference was minor. We investigated the effect on anxiety level with the elevated plus-maze test. Neither an anxiety level enhancement effect nor a reduction effect was observed in the offspring by scent exposure. It can be said that scent exposure during the fetal period does not have a clear impact on offspring in the next-generation, as far as the experiments that we conducted showed. (J Osaka Dent Univ 2021; 55: 163-167)

Improving the reliability of orthodontic surgical simulations and postorthodontic treatment models requires accurately matching the computed tomography (CT) images of craniofacial bone and dental casts. We investigated the usefulness of a novel scanning marker (Marker A) that we devised for the purpose of increasing this accuracy. We compared it with a conventional scanning marker (Marker B) by attaching both of these markers to a dry skull and a maxillary dental cast obtained from the skull and identifying them several times on CT images. We investigated the accuracy of identification of each marker by measuring certain parameters on frontal and lateral images and superimposing these images. For every measurement parameter, there was lesser variation in the measured values with Marker A than with Marker B, with the variation being close to or less than the scanning voxel size. The errors during superimposition were also smaller for Marker A than those for Marker B, with the images being almost identical. These results confirmed that this new scanning marker improves the accuracy of matching the craniofacial bone and dental cast CT images to less than the voxel size, even with current CT accuracy. (J Osaka Dent Univ 2021; 55: 169-177)

Periodontal disease is characterized by chronic inflammation of periodontal tissues due to infection caused by pathogens. Plasmalogen (Pls) is a glycerophospholipid thought to possess anti-inflammatory properties. We investigated the effect of Pls on the expression of intercellular adhesion molecule-1 (ICAM-1) stimulated by lipopolysaccharide (LPS) derived from Porphyromonas gingivitis (Pg). LPS derived from Pg (Pg-LPS) was used to stimulate cultured mouse vascular endothelial cells (MS-1). The expression of ICAM-1 was examined by real-time PCR and flow cytometry analysis. We found that Pg-LPS induced ICAM-1 in MS-1 in a dose-dependent manner. The highest level of ICAM-1 expression was observed 6 h after Pg-LPS stimulation. Pretreatment with Pls resulted in the inhibition of Pg-LPS-induced ICAM-1 expression in MS-1. Additionally, the protein level of ICAM-1 was significantly suppressed. These results show that Pls inhibits the expression of ICAM-1 in MS-1, suggesting that Pls may suppress and control the inflammatory response by regulating ICAM-1 expression in periodontal disease. (J Osaka Dent Univ 2021; 55: 179-185)

Rapid environmental changes and nutritional deficiencies may affect the size of teeth and jaws and lead to dental abnormalities. However, there is no clear evidence yet. The Japanese economy and diet have changed remarkably in the past several decades. We obtained dental casts from Japanese adult men in 1947, 1962, 1977, 1992 and 2007 (Groups I-V) and compared the dimensions of the teeth and dental arches. We found that the maxillary dental arch in Group II was narrower than in Group IV, and that of the mandibular dental arch in Group II was narrower than in Groups I, IV and V. The mesiodistal dimension of the maxillary canine, maxillary first molar, and mandibular canine, first molar and second molar of Group II tended to be smaller than that in other groups. However, the depth index of the maxillary/mandibular dental arch of all groups except for Group I showed increases. In addition, the width index of the maxillary/mandibular dental arch of Group V was greater than in Group III. We found that although the tooth size and the dental arch of subjects born in 1962 were narrower, the size of the mandible steadily decreased over approximately 60 years regardless of differences in the size of teeth and dental arch obtained from subjects born in 1962. Consequently, we think that changes in the size of teeth and dental arch and changes in the maxillomandibular relationship might occur for different reasons. (J Osaka Dent Univ 2021; 55: 187-194)