This in vitro study investigated the effect of skin markers on the accuracy of three-dimensional virtual patient reconstructions created using an intraoral scanner (IOS). A digital reference model (DRM) was fabricated by scanning the mannequin head with a maxillary dentition model. Perioral scans, including dentition (POSD), were acquired using two IOS systems, Medit i700 (Medit, Seoul, Republic of Republic of Korea) and Trios 4 (3shape A/S, Copenhagen, Denmark), both with and without skin markers. The nasal-glabellar region, an area relatively stable during facial movement, was used to integrate POSD data with facial data and maxillary dental models to create digital experimental models (DEMs). Accuracy was evaluated by measuring the three-dimensional positional deviations of the maxillary arch between the DRM and DEMs. The results demonstrated a significant interaction between IOS type and skin marker use. While both IOS systems showed clinically acceptable accuracy, the Medit i700 exhibited a significant improvement in accuracy when skin markers were applied, unlike the Trios 4, which showed minimal difference. This suggests that the effectiveness of skin markers is influenced by the specific scanning technology and algorithms of each IOS. (J Osaka Dent Univ 2025; 59: 219-233)

Obesity is a major risk factor for type 2 diabetes mellitus, and a bidirectional association between type 2 diabetes mellitus and periodontal disease has been established. However, morphological changes in the lingual gingiva of mandibular first molars in an obese type 2 diabetes mellitus environment in rat models remain poorly studied. In this study, we compared obese rat models of type 2 diabetes mellitus with normal rats to investigate morphological differences in the mucosal epithelium, subepithelial connective tissue, and microvascular architecture of the lingual gingiva. The obese type 2 diabetes mellitus group showed significant mucosal epithelial thickening, particularly in the keratinized and granular layers of the upper gingiva, with enhanced desquamability of superficial epithelial cells. Degenerative changes in the subepithelial connective tissue included fine wavy primary ridges and an increased number of secondary ridges. The microvascular architecture revealed significantly smaller capillary diameters and heterogeneous capillary networks. These findings suggest that the obese type 2 diabetes mellitus environment induces abnormal keratinization, enhanced epithelial desquamability, connective tissue degeneration, and vascular remodeling associated with microangiopathy, potentially affecting periodontal tissue homeostasis, as well as providing insights into the mechanisms of periodontal disease progression in diabetes and obesity. (J Osaka Dent Univ 2025; 59: 235-253)

To reduce the amount of tooth cutting during dental caries treatment, the improvement of dental caries-detecting liquid and development of apparatuses to selectively remove dental caries have been performed. We experimentally produced a dental caries-detecting liquid containing a compound with a primary amino group (HLA) to improve the absorptivity of the Er: YAG laser, and evaluated the removal efficiency of dyed artificial carious dentin irradiated by the laser. As a result, because the dental caries-detecting liquid containing HLA increased the laser absorptivity, as well as the depth of cavity preparation and volume of dentin removed by laser irradiation, the possibility of the selective removal of dental caries using a laser with a caries-detecting liquid containing the high laser-absorptive compound was suggested. (J Osaka Dent Univ 2025; 59: 255-261)

Pulpitis most often develops when microorganism invade the dental pulp cavity as a result of various factors, including caries. Tumor necrosis factor (TNF)-α, an inflammatory cytokine secreted during immune responses, plays a central role in pulpitis development. Interleukin (IL)-6 is a cytokine with various physiological functions, including immune control, inflammatory control, and bone metabolism. We assessed the effect of TNF-α on IL-6 production and signaling using human dental pulp-derived fibroblasts (HDPFs). We found that, TNF-α promoted IL-6 production. It also promoted the transforming growth factor β-activated kinase (TAK)-1 phosphorylation, which peaked 10 minutes after stimulation. Phosphorylation was also promoted by mitogen-activated protein kinases downstream of TAK1. Overall, our results suggest that TNF-α promotes IL-6 production in HDPFs through a mechanism mediated by the phosphorylation of TAK1 and mitogen-activated protein kinases. (J Osaka Dent Univ 2025; 59: 263-268)

TNF-α is a key mediator of inflammatory reactions in periodontal disease, and its expression is tightly regulated by multiple intracellular signaling pathways. We examined how various signaling inhibitors affected TNF-α gene expression in THP-1 cells stimulated with Porphyromonas gingivalis lipopolysaccharide (Pg-LPS). Real-time PCR analysis revealed that the MEK inhibitor U0126 markedly suppressed both baseline and Pg-LPS-induced TNF-α expression, suggesting a stimulatory role for the ERK pathway. In contrast, the JNK inhibitor SP600125 and the p38 inhibitor SB203580 significantly increased TNF-α expression, indicating that these MAPK subtypes may exert inhibitory effects under Pg-LPS stimulation. Furthermore, inhibition of CaMKII with KN93 modestly enhanced TNF-α expression, suggesting a negative regulatory function for CaMKII. Inhibitors of protein kinase A (H89) and PPARγ (GW9662) showed no significant effect on TNF-α expression. These results indicate that the ERK pathway acts as a primary promoter, whereas JNK, p38, and CaMKII may function as suppressors of TNF-α gene expression in THP-1 cells under Pg-LPS stimulation. These results reveal that TNF-α expression is differentially regulated by specific signaling pathways, with implications for understanding the pathogenesis of periodontal inflammation and developing targeted anti-inflammatory therapies. (J Osaka Dent Univ 2025; 59: 269-274)

The dimensional changes over time of three-dimensionally printed dental moldings were investigated under non-light-shielding conditions, aiming to clarify how long the photopolymerized moldings can maintain accuracy when exposed to light. This is crucial for ensuring the precision required in dental technology, especially for cases expected to increase in the future when models may not be used. Furthermore, the material properties and storage conditions of the DLP method, which is the mainstream method for dental 3D printers, were considered, providing fundamental data to enhance clinical practicality. Nissin's edentulous models were scanned with a dental scanner to create STL data. The STL data included measurement markers at six locations (two each on the anterior, premolar, and molar regions) and added landmarks on the palatal region to create experimental STL data. These STL data were output using a 3D printer to create 3D-printed models, which were stored under LED lighting and scanned weekly with a dental scanner. Subsequently, the 3D-printed models were measured with a dental scanner to create measurement STL data. Using GOMInspect2016, the experimental STL data and measurement STL data were overlaid to create a color map. Finally, the measurement markers A, B, C, D, E, and F were identified, and the distances between points were measured (A-B, A-C, A-D, A-E, A-F, B-C, B-D, B-E, and C-D). The results showed significant dimensional changes between points over time, with approximately 20-μm changes from 0 to 2 weeks. The changes were significantly larger at 3 weeks, and no differences were observed after 3 weeks. (J Osaka Dent Univ 2025; 59: 275-279)

The present study examined the onomatopoeia used to describe the texture of soft azuki bean jelly, with and without the use of dentures. The study participants included 80 individuals, comprising 40 dentate and 40 wearing removable maxillary dentures (49-81 years old). Soft azuki bean jellies (mashed and strained) were used as the test foods, a portion of which was eaten. Chi-square test (5% level of significance) results revealed a significant difference in the term “chunky" used to describe the strained type of soft azuki bean jelly, between dentate and denture wearer. Furthermore, multiple-response analysis revealed that the similarity of the scale for each onomatopoeia for food texture, both groups were at a close distance for the strained type soft azuki bean jelly. However, the food texture scales of the onomatopoeia clustering around them differed. These results suggested that onomatopoeia used to express the texture of soft azuki bean jelly with and without dentures differs only for the strained type of soft azuki bean jelly. (J Osaka Dent Univ 2025; 59: 281-288)

Ameloblastic carcinoma (AC) is a malignant disease of odontogenic origin with histological features of both ameloblastoma (AB) and malignant tumors. This paper will report on two cases of AC occurring in the mandible, one of which developed lymph node and lung tissue metastases. Case 1 represents a 51-year-old woman who presented to our hospital with a rapidly increasing mass in her mandibular gingiva. Biopsy revealed AC, and mandibular marginectomy and tumor resection were performed. The tumor did not recur in the 4 months after treatment and is under follow-up observation. Case 2 represents a 48-year-old male, physical examination found that a mandibular mass was not completely disposed of a previous surgery in 2016. The patient attended our hospital, one year later after resection of the tumor. Again, the pathology diagnosis was AC. In June of 2017, contrast CT found metastasis to the lymph nodes. Lung metastasis was found on March 2018. Along with a clinical examination, the pathological diagnosis needs an imaging confirmed the diagnosis. The treatment was mainly surgical resection, with regular observation to monitor metastasis. (J Osaka Dent Univ 2025; 59: 289-294)