Relationship between the presence of oral herpes simplex virus type 1 DNA and oral hygiene condition in dependent older individuals

This study aimed to investigate the association between the presence of oral herpes simplex virus type 1 (HSV‐1) DNA and oral hygiene condition in dependent older adults.We focused on 45 dependent older individuals (11 males and 34 females; median age 89 years) with certified needs for long‐term support or nursing care. Real‐time PCR analysis was performed to identify HSV‐1 DNA from samples collected from the tongue surface via swab brushes. Concurrently, the detection of the 16S rRNA gene for periodontopathic bacteria such as Porphyromonas gingivalis, Treponema denticola, and Fusobacterium nucleatum was conducted.Among the participants, HSV‐1 DNA was detected in seven out of 45 (15.6%). No significant association was observed between HSV‐1 DNA and age, sex, body mass index, dependency status, or medical history. While the rate of HSV‐1 DNA positivity was higher in participants with suboptimal or poor oral hygiene (28.6%) compared with those with good oral hygiene (9.7%), the association was not statistically significant. Similarly, a reduction in oral wetness was noted in HSV‐1 DNA‐positive participants compared with their HSV‐1 DNA‐negative counterparts, but this was also not statistically significant. Interestingly, a significant association was found between the presence of HSV‐1 DNA and P. gingivalis (P = 0.01).It remains unclear whether the presence of oral HSV‐1 DNA is associated with poor oral hygiene and dry mouth in dependent older individuals. Co‐infection of HSV‐1 and P. gingivalis may contribute to the pathology of periodontitis.