Pro-inflammatory cytokines at zirconia implants and teeth. A cross-sectional assessment

OBJECTIVES: The aim of this study was to compare the expression of host-derived markers in peri-implant/gingival crevicular fluid (PCF/GCF) and clinical conditions at ceramic implants and contralateral natural teeth. As a secondary objective, we compared zirconia implants with titanium implants. METHODS: One zirconia implant (ZERAMEX® Implant System) and one contralateral natural tooth were examined in 36 systemically healthy subjects (21 males, 15 females, mean age 58). The levels of Il-1β, Il-1RA, Il-6, Il-8, Il-17, b-FGF, G-CSF, GM-CSF, IFNɣ, MIP-1β, TNF-α, and VEGF were assessed in PCF/GCF using the Bio-Plex 200 Suspension Array System. The plaque index (PI), gingival index (GI), probing depth (PD), and bleeding on probing (BOP) were assessed at six sites around each implant or tooth. Titanium implants were also assessed when present (n = 9). RESULTS: The zirconia implants were examined after a loading period of at least 1.2 years (average 2.2 years). The mean PI was significantly lower at zirconia implants compared to teeth (p = 0.003), while the mean GI, PD, and BOP were significantly higher (p < 0.001). A correlation was found in the expression of Il-1RA, Il-8, G-CSF, MIP-1β, and TNF-α at zirconia implants and teeth. The levels of IL-1β and TNF-α were significantly higher at zirconia implants than at teeth. No significant differences were found between zirconia and titanium implants. A correlation was found between the levels of IL-1RA, IL-8, GM-CSF, and MIP-1β at zirconia and titanium implants. CONCLUSIONS: The correlation in the expression of five biomarkers at zirconia implants and teeth, and of four biomarkers at zirconia and titanium implants, is compatible with the existence of a patient-specific inflammatory response pattern. Higher mean GI, PD, and BOP around implants suggests that the peri-implant mucosa may be mechanically more fragile than the gingiva. CLINICAL RELEVANCE: Similar expression of selected biomarkers at zirconia implants and teeth and at zirconia and titanium implants reflects existence of patient-specific inflammatory response patterns.