Herpes Simplex I virus impairs regenerative outcomes of periodontal regenerative therapy in intrabony defects. A pilot study

Aim: To evaluate the impact of herpesvirus type-1 and -2 on the clinical outcomes of periodontal regenerative procedures in isolated deep intrabony pockets, in an experimental population with no detectable periodontal pathogens. Materials and Methods: Seventeen periodontal intraosseous defects in 17 moderate- to-advanced periodontitis patients were treated with regenerative therapy and amelogenins. Microbiological evaluation was performed at baseline (after the completion of initial therapy) and at 1 year to exclude the presence of periodontal pathogens. Herpesviruses-1 and -2 DNA were quantified in the pocket tissues associated to the intrabony defect using molecular assays. Clinical attachment level (CAL), probing pocket depth (PPD) and gingival recession (REC) were recorded at baseline and at 1 year. Results: After 1 year, the 17 defects resulted in significant CAL gain, PPD reduction and REC increase. HSV-1 was detected in five patients. Herpesvirus-2 was never found. The two subpopulations positive or negative to herpesvirus-1 were homogeneous at baseline. At 1 year, the five herpesvirus-1 positive patients resulted in lower amounts of CAL-gain and PPD reduction and greater amount of REC with respect to the 12 herpesvirus-1 negative patients. Conclusions: The presence of herpesvirus-1 at baseline is associated with poor clinical outcomes following regenerative therapy.