Effects of Dicationic Imidazolium-Based Ionic Liquid Coatings on Oral Osseointegration of Titanium Implants: A Biocompatibility Study in Multiple Rat Demographics

Abstract

Dicationic imidazolium-based ionic liquids with amino acid anions, such as IonL-phenyl-alanine (IonL-Phe), have been proposed as a multifunctional coating for titanium (Ti) dental im-plants. However, there has been no evaluation of the biocompatibility of these Ti coatings in the oral environment. This study aims to evaluate the effects of IonL-Phe on early healing and osseoin-tegration of Ti in multiple rat demographics. IonL-Phe-coated and uncoated Ti screws were im-planted into four demographic groups of rats to represent biological variations that could affect healing: young males (YMs) and females (YFs), ovariectomized (OVXFs) females, and old males (OMs). Samples underwent histopathological and histomorphometric analysis to evaluate healing at 7 and 30 days around IonL-coated and uncoated Ti. The real-time quantitative polymerase chain reaction was also conducted at the 2-and 7-day YM groups to evaluate molecular dynamics of healing while the IonL-Phe was present on the surface. IonL-coated and uncoated implants demon-strated similar histological signs of healing, while coated samples’ differential gene expression of immunological and bone markers was compared with uncoated implants at 2 and 7 days in YMs. While YMs presented suitable osseointegration for both uncoated and IonL-Phe-coated groups, de-creased success rate in other demographics resulted from lack of supporting bone in YFs and poor bone quality in OVXFs and OMs. Overall, it was found that IonL-coated samples had increased bone-to-implant contact across all demographic groups. IonL-Phe coating led to successful osseoin-tegration across all animal demographics and presented the potential to prevent failures in scenar-ios known to be challenged by bacteria.