Prevalence of several herpesviruses and human papillomavirus in acute apical abscesses

To investigate and compare the radiographic size of acute apical abscess lesions for the presence of Epstein-Barr virus (EBV), human cytomegalovirus (HCMV), human herpesvirus-6 (HHV-6) and human papillomaviruses (HPV) DNA by means of the real-time polymerase chain reaction (PCR) method.

According to the radiographic size of acute apical abscess lesions, 11 lesions were categorized as large (≥5 mm) and 10 lesions as small (<5 mm). DNA extracts from purulent exudate aspirates of 21 cases of acute apical abscess and 10 control samples were evaluated for the presence of viral loads using real-time PCR methods following the kit protocols recommended by the manufacturers. Statistical analysis was performed using chi-squared test with Yates's correction and Fisher's exact test.

HCMV DNA was detected in 27% of large and in 10% of small abscess lesions. EBV was identified in 18% of large and in 10% of small abscess lesions. HPV and HHV-6 DNA were found in 9% of large abscess lesions. None of the small abscess lesions contained HPV or HHV-6 DNA. Viral coinfections were found in two samples as the pair of HCMV/EBV and HCMV/HHV-6 from large abscess lesions. No significant associations were found between any of the target viruses and size of periapical lesions. As for the healthy pulps used as noninflamed controls, no control specimens contained viral DNA.

HCMV was the most frequent herpesvirus amongst the target viruses in samples from both large and small apical abscess lesions. In large lesions, EBV and HHV-6 tended to occur in coinfection with HCMV. Additional studies are required to elucidate the role of herpesviruses in the pathogenesis of periapical abscess.