2025 年 92 巻 1 号 p. 7-23
Introduction : Dental calculus is a major risk factor for the accumulation of dental plaque, which leads to the progression of periodontitis. Dental calculus forms through the mineralization of dental plaque with the involvement of bacterial communities, and its formation may be influenced by the distinct environments of the supragingival and subgingival regions, similar to dental plaque. Additionally, calculus itself may affect periodontitis progression. However, no studies have examined the bacterial compositions and the differences between supragingival calculus (SUP) and subgingival calculus (SUB) in Japanese populations. This study aims to clarify and compare the bacterial communities and structures in SUP and SUB.
Methods : SUP and SUB samples were collected from 31 patients. The bacterial communities were analyzed using 16S rDNA amplicon sequencing, differential abundance analysis, and network analysis.
Results : While alpha diversity showed no significant differences between SUP and SUB, beta diversity analysis revealed distinct bacterial communities between the two groups. Aerobic bacteria dominated in SUP, whereas anaerobic bacteria were more prevalent in SUB. Corynebacterium matruchotii exhibited a high average relative abundance in both SUP and SUB. Mogibacterium timidum had a statistically significantly higher relative abundance in SUB compared to SUP and was strongly correlated with many bacterial taxa in the network of SUB.
Conclusion : The bacterial communities in dental calculus are shaped by the specific environment in which they form, leading to differences between the supragingival and subgingival regions. C. matruchotii was a prominent bacterial taxon in both regions, while M. timidum played a central role in the subgingival region.
