Background: The presence of viruses in healthy teeth has not been extensively studied, although some viral traces have been detected in both healthy and diseased dental pulps in previous studies focusing primarily on a single species. The aim of this study is to clarify the persistence of DNA viruses in dental tissues and their impact on tissue composition.

Materials and methods: Here, the prevalence of persistent DNA viruses in intact third molars (n = 17) was assessed via quantitative PCR to detect human parvovirus B19 (B19V), torque teno virus (TTV) and nine human herpesviruses. Also, H&E-stained tissue sections of the samples were analyzed for any potential inflammatory process. RNAscope in-situ hybridization was performed for B19V, TTV and HHV7 subsequently.

Results: Viral DNA of five different viruses was detected in 5 of the 17 samples (29.4%) including B19V (n = 2), TTV (n = 2), HHV7 (n = 2), HCMV (n = 1) or EBV (n = 1) in dental pulps with no signs of cytopathic effect, inflammatory cell accumulations or necrosis. RNAscope in-situ hybridization confirmed the presence of B19V and TTV in non-inflamed pulp tissue.

Conclusions: These findings emphasized that even in the absence of a disease evaluated by histology, dental pulp can harbor DNA viruses and be an anatomical site of virus tropism, suggesting viral persistence rather than direct pathogenic activity.

Keywords: DNA viruses; RNAscope in-situ hybridization; Technovit® 9100; Virology; human hard tissue; odontology; qPCR.