Although in vivo studies have explored the relationship between oral environment and microbial communities, a precise analysis of the effects of environmental pH on oral microbiota remains challenging owing to their complexity and external influences. This study aimed to investigate the effect of environmental pH on the structure and diversity of oral microbiota in vitro. Tongue coating samples from ten participants were cultured anaerobically at six pH levels (5.5–8.0) using adjusted media. After DNA extraction, high-throughput sequencing of the 16s rRNA V3–V4 region was performed. Microbial diversity was analyzed using alpha and beta diversity indices, and differential taxa were identified using linear discriminant analysis effect size (LEfSe). Alpha diversity analysis revealed reduced diversity at pH 5.5 and 8.0. Beta diversity revealed that microbial communities at pH 5.5, 7.5, and 8.0 were separated from those at pH 7.0. LEfSe identified bacterial species that were significantly altered at pH 5.5 and 8.0. Environmental pH significantly influences the diversity and composition of microbial communities, with substantial changes occurring under acidic or alkaline conditions. These findings provide deeper insight into how oral biofilms respond to pH variations, underscoring the critical role of pH in oral microbiota dynamics.

Identifying reliable biomarkers in saliva can be a promising approach to developing a rapid diagnostic kit for detecting vascular aging. This study investigated the most suitable reference gene for polymerase chain reaction (PCR) in saliva that is not affected by vascular aging variables. Whole saliva samples were collected to assess the expression of reference genes: actin beta (ACTB), 18S ribosomal RNA (18S rRNA), beta-2-microglobulin, and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). The most abundantly expressed gene was 18S rRNA, and the least expressed gene was GAPDH. Four genes were ranked according to their relative stability, as determined by mathematical algorithms, indicating that ACTB and 18S rRNA were stably expressed as reference genes. 18S rRNA was identified as the most promising reference gene for detecting systemic diseases using saliva from patients with vascular aging in these limited experimental conditions.

Purpose: This study evaluated the effects of two additive manufacturing technologies and three orientations on the accuracy of three-dimensional (3D)-printed complete dentures. Additionally, we examined whether resin differences affected the accuracy of the denture bases under varying printing systems and orientations.Methods: We printed denture bases using digital light processing (DLP) and a liquid crystal display (LCD) in three orientations (0°, 45°, and 90°) with two photopolymer resins (n = 6). Intaglio surfaces were scanned to obtain experimental data. We evaluated trueness by superimposing experimental data onto master data, and assessed precision by pairing and superimposing two of the six datasets. Deviation was evaluated using root mean square (RMS) and color map data. Statistical analysis was conducted using the Kruskal–Wallis method and Mann–Whitney U test (α = 0.05).Results: The DLP printer achieved the highest trueness at an orientation of 90°, whereas the precision was minimally affected by the orientation or printing systems. DLP printers performed well with both recommended and non-recommended resins; however, LCD printers demonstrated better accuracy with the recommended resins. At 0° orientation, the trueness color map for both printers showed negative deviation patterns over the entire palatal surface. Across all manufacturing methods, the precision color maps indicated high reproducibility.Conclusions: Printing system and orientation affect the trueness of 3D-printed dentures. DLP printers set at 90° demonstrated superior trueness for clinical applications. The accuracy was affected by resin, printer, and orientation.

Salivary biomarkers are promising molecules for diagnosing systemic diseases. Cytidine/uridine monophosphate kinase 2 (CMPK2) is associated with various systemic diseases. However, little is known about the role of the CMPK2 gene in saliva and dyslipidemia. This study investigated the relationship between serum lipid levels and Cmpk2 mRNA expression in the saliva of dyslipidemic mice. Additionally, immunofluorescence staining was employed to assess the localization of the CMPK2 protein in the submandibular gland. Two types of dyslipidemic mice were utilized: mice fed a high-fat and high-cholesterol (HFHC) diet and genetically dyslipidemic ApoE-deficient mice. The mice at 9 to 46 weeks were analyzed for serum lipid levels, Cmpk2 mRNA expression in saliva, and CMPK2 protein localization in the submandibular glands. Both dyslipidemic mice displayed elevated low-density lipoprotein cholesterol and total cholesterol in serum. ApoE-deficient mice apparently exhibited increased Cmpk2 expression in saliva. Immunofluorescence staining indicated that CMPK2 proteins were primarily localized in the serous acini, potentially associated with the secretion of Cmpk2 mRNA in saliva. These findings suggest that Cmpk2 mRNA increases and is detectable in the saliva of dyslipidemic mice, providing a viable experimental model to assess the potential use of CMPK2 as a biomarker for dyslipidemia.

Several protocols have been reported for inducing parathyroid differentiation from human pluripotent stem cells in vitro. However, the efficiency of terminal differentiation into mature parathyroid cells remains limited. In this study, we performed comparative transcriptomic analyses of parathyroid lineage-induced human induced pluripotent stem (iPS) cells to clarify their developmental stage identity. Comparative analyses with adult parathyroid adenoma, used as a surrogate reference for mature parathyroid cells, and thymuses revealed that the differentiated cells exhibited gene expression patterns consistent with early-stage parathyroid and thymus development, including TBX1, which is required for fate determination of the parathyroid–thymic primordium. On the other hand, the expression of mature parathyroid marker genes, such as PTH, GCM2, and the calcium-sensing receptor (CaSR), remained markedly lower than that in parathyroid adenoma. Under the differentiation conditions and durations examined, application of modified differentiation protocols did not significantly enhance the expression of mature parathyroid markers, although pharyngeal pouch developmental gene expression was maintained. Our findings indicate that current in vitro differentiation systems effectively induce the parathyroid–thymic primordium stage, while a developmental bottleneck at the transition from the primordium toward parathyroid lineage commitment remains.

Objectives: This non-randomized and self-selected controlled intervention study aimed to examine the effects of simple nutritional guidance provided by registered dietitians on the oral function and body composition of patients in a general dental clinic in Japan. Methods: Among patients aged ≥50 years who visited a single dental clinic for regular maintenance, those who accepted and declined nutritional guidance were classified as being in the “guidance group (G group)” and “nonguidance group (nG group)”, respectively. The oral moisture content, masticatory performance, tongue/lip motor function, maximum tongue pressure, and swallowing function were assessed. Additionally, we assessed 10 body composition parameters using a body composition analyzer. Patients in the G group received monthly nutritional guidance from a registered dietician. At 3 months, changes in oral function and body composition were examined and between-group comparison in changes in dietary habits was performed. Results: A two-way analysis of variance revealed a main effect of time and an interaction between time and group for oral function only, and improvements in masticatory performance scores, maximum tongue pressure, and swallowing function were observed in the G group (n = 20). Compared with the nG group (n = 18), the G group had a significantly higher proportion of participants with a reported increase in the variety and amount of consumed food. Conclusions: Although this is the preliminary trial with a small sample and high risk biases, our findings suggest the possibility that 3 months of nutritional guidance at a general dental clinic in Japan may improve oral function.