The soft tissue immunologic response to hydroxyapatite-coated transmucosal implant surfaces : a study in humans

ObjectiveTo evaluate the soft tissue response in humans immunologically and histologically after placement of mini-implants coated with or without nano-size hydroxyapatite coatings. Material and MethodsCommercially pure (cp) titanium mini-implants (n=13) or nano-hydroxyapatite-coated ones (n=12) were randomly placed into partially edentulous jaws. Crevicular fluid was sampled 1week after placement and subjected to quantitative polymerase chain reaction analysis to explore the inflammatory markers. After 8weeks, implants and surrounding soft and hard tissue were trephined, and undecalcified ground sections were prepared. Inflammatory cell accumulation within a defined region of interest in the soft tissue was quantified histomorphometrically. ResultsNo statistically significant differences in immunological response to the different implant surfaces were found for IL-6 (p=.438), TGF-2 (p=.467), MMP-8 (p=.758), CCL-3 (p=.758), IL-8 (p=.771), and IL-1 (0.771). Histomorphometric evaluation presented no statistically significant difference between the two mini-implant surfaces with regards to number of inflammatory cells (p=.669). ConclusionNano-hydroxyapatite-coated surfaces in the transmucosal region yielded similar inflammatory response and is suggested to be as biocompatible as commercially pure titanium surfaces