Background: Endodontic sealers or their toxic components may become inflamed and lead to delayed wound healing when in direct contact with periapical tissues over an extended period. Moreover, an overfilled sealer can directly interact with adjacent tissues and may cause immediate necrosis or further resorption. Therefore, the treatment outcome conceivably depends on the endodontic sealer's biocompatibility and osteogenic potential. This study aimed to evaluate the cell viability and osteogenic effects of four different sealers in osteoblastic cells. Methods: AH Plus (resin-based sealer), Pulp Canal Sealer EWT (zinc oxide-eugenol sealer), BioRoot RCS (calcium silicate-based sealer), and Well-Root ST (MTA-based calcium silicate sealer) were mixed strictly according to the manufacturer's instructions, and dilutions of sealer extracts (1/2, 1/5 and 1/10) were determined. Cell viability was measured using the water-soluble tetrazolium-8 (WST-8) assay. Differentiation was assessed by alkaline phosphatase (ALP) activity and mineralized nodule formation by Alizarin Red S staining. Results: The cell viability of the extracts derived from the sealers excluding Well-Root ST was concentration dependent, with sealer extracts having the least viability at a 1/2 dilution. At sealer extract dilution of 1/10, the test groups showed the same survival rate as that control group, with the exception of BioRoot RCS. Among all experimental groups, BioRoot RCS showed the highest cell viability after 48 hours. The ALP activity was significantly higher in a concentration-dependent manner. Furthemore, all four materials promoted ALP activity and mineralized nodule formation compared to the control at 1/10 dilutions. Conclusion: This is the first study to highlight the differences in biological activity of these four materials. These results suggest that the composition of root canal sealers appears to alter the form of biocompatibility and osteoblastic differentiation.

We determined the association between the number of natural and implant teeth with activities of daily living (ADL) and instrumental ADL (IADL) levels in middle-aged and older adults aged ≥ 55 years. We included 6,925 participants, who underwent a computer-assisted personal interview in the 7th Korean Longitudinal Study of Aging. After controlling for general characteristics, the associations between the number of natural and implant teeth with ADL and IADL levels were examined using multiple regression analysis. The participants had 21.2 natural teeth and 1.08 implant teeth on average. The ADL and IADL levels were 0.61 and 1.56, 0.40 and 1.16, and 1.10 and 0.31 in participants with ≤ 9, 10–19, and ≥ 20 teeth, respectively. There was no significant association between ADL and the number of natural and implant teeth (p > 0.05). However, a one-unit increase in IADL score was associated with a reduced number of natural (β = −0.031, p < 0.001) and implant (β = −0.194, p = 0.006) teeth. Difficulties regarding IADL were associated with fewer natural and implant teeth, suggesting that maintaining and managing the number of teeth is critical to promoting the health of middle-aged and older adults.

Background: When cells are damaged by nicotine, cellular senescence due to oxidative stress accelerates. In addition, stress-induced inflammatory response and cellular senescence cause the accumulation of damaged organelles in cells, and autophagy appears to remove them. Conversely, when autophagy is reduced, harmful cell components accumulate, and aging is accelerated. This study aimed to determine the association between nicotine-induced cellular senescence and autophagy expression patterns in human gingival fibroblasts. Methods: Cells were treated with various concentrations of nicotine (0, 0.1, 0.5, 1, 2, and 5 mM) and 10 nM rapamycin was added to 1 mM nicotine to investigate the relationship between autophagy and cellular senescence. Cell viability was confirmed using WST-8 and the degree of cellular senescence was measured by SA--gal staining. The expression of the inflammatory proteins (COX-2 and iNOS) and autophagy markers (LC3-II, p62, and Beclin-1) was analyzed by western blotting. Results: The cell viability tended to decrease in a concentration-dependent manner. COX-2 showed no concentration-dependent expression and iNOS increased in the 0.5 mM nicotine treated group. The degree of cellular senescence was the highest in the 1 mM nicotine treatment group. In the group treated with rapamycin and nicotine, the conversion ratio of LC3-II to LC3-I was the highest, that of p62 was the lowest, and the level of Beclin-1 proteins was significantly increased. Furthermore, the degree of cellular senescence was reduced in the group in which rapamycin was added to nicotine compared to that in the group treated with nicotine alone. Conclusion: This study provides evidence that autophagy activated in an aging environment reduces cellular senescence to a certain some extent.

Very poor oral health, common among older adults, is associated with cognitive decline.This study aimed to investigate the association between denture use, chewing ability, and cognitive function in Korean middle-aged adults using samples representing middle-aged people at the national level. This longitudinal study included 9,998 middle-aged adults via Korea Longitudinal Study of Aging 7th special survey data. Denture use, chewing ability, health-related factors, and general characteristics were assessed by the Computer Assisted Personal Interview. After controlling general characteristics using a generalized estimating equation model, the association of denture use and MMSE scores with chewing ability of those with or without dentures and MMSE scores were analysed. Twenty-four percent of participants wore dentures among them, 35.1% complained of difficulty chewing when wearing dentures. Among participants who did not wear dentures, 16.4% complained of difficulty chewing. MMSE scores were lower among denture-wearers than non-denture wearers (β = -0.026, p &lt; 0.001). In both groups, MMSE scores decreased with chewing difficulty and were significantly reduced among non-denture wearers (p &lt; 0.05). Chewing ability was closely associated with cognitive function. Given the negative effect of difficulty chewing on cognitive function, maintaining chewing ability should be of great concern.