Simple Summary The objective of this study was to uncover the association between oral human herpesvirus-6 (HHV-6) and HHV-7 infection and periodontitis. Oral HHV-6 and HHV-7 DNA were analyzed by a real-time polymerase chain reaction using tongue swab samples from 74 older adults. Of the 74 participants, one participant (1.4%) was HHV-6 DNA-positive and 36 participants (48.6%) were HHV-7 DNA-positive. HHV-7 DNA-positive participants had a higher prevalence of diabetes (16.7%) than HHV-7 DNA-negative participants (7.9%). However, there was no significant association between HHV-7 DNA positivity and diabetes. Oral HHV-7 infection was significantly associated with a deep periodontal pocket (p = 0.04). HHV-7 DNA-positive participants had a higher positive rate of a periodontal pocket with BOP (25.0%) than the HHV-7 DNA-negative participants (7.9%). Additionally, the HHV-7 DNA-positive participants had higher PISA values (52.7 mm(2)) than the HHV-7 DNA-negative participants (47.2 mm(2)). These results indicate that oral HHV-7 infection is associated with active periodontitis. However, there was no statistically significant association between HHV-7 and a >= 6-mm periodontal pocket with BOP positivity or the PISA value. Oral herpesviruses other than HHV-7 may be more closely associated with periodontitis. It is necessary to clarify the association between HHV-7 and periodontitis with the detection of HHV-7 in the periodontal pocket. Background: The associations between oral human herpesvirus-6 (HHV-6) and HHV-7, periodontal conditions, and lifestyle-related diseases, such as hypertension, diabetes, and dyslipidemia, have not been fully investigated in older adults. Methods: Seventy-four older patients who visited Hiroshima University Hospital were enrolled. Tongue swab samples were employed, and a real-time polymerase chain reaction was performed to detect HHV-6 and HHV-7 DNA. Dental plaque accumulation, probing pocket depth, and bleeding on probing (BOP) (i.e., a sign of periodontal inflammation) were examined. The periodontal inflamed surface area (PISA) value (i.e., an indicator of the severity of periodontitis) was also examined. Results: Of the 74 participants, one participant (1.4%) was HHV-6 DNA-positive and 36 participants (48.6%) were HHV-7 DNA-positive. A significant association between HHV-7 DNA and probing depth was found (p = 0.04). The HHV-7 DNA-positive participants had a higher positive rate of a >= 6-mm periodontal pocket with BOP (25.0%) than the HHV-7 DNA-negative participants (7.9%). Additionally, the HHV-7 DNA-positive participants had a higher PISA value than the HHV-7 DNA-negative participants. However, there was no significant association between HHV-7 and the PISA value (p = 0.82). No significant association was found between HHV-7 and lifestyle-related diseases (p > 0.05). Conclusions: Oral HHV-7 infection is associated with a deep periodontal pocket.
