Investigation of the early healing response to dicationic imidazolium-based ionic liquids: a biocompatible coating for titanium implants.

Dicationic Imidazolum-based ionic liquids with amino acid anions (IonL) have been proposed as a multifunctional coating for titanium dental implants, as their properties have been shown to address multiple early complicating factors while maintaining host cell compatibility. This study aims to evaluate effects of this coating on host response in the absence of complicating oral factors during the early healing period using a subcutaneous implantation model in the rat. IonLs with the best cytocompatibility and antimicrobial properties (IonL-Phe, IonL-Met) were chosen as coatings. Three different doses were applied to cpTi disks and subcutaneously implanted into 36 male Lewis rats. Rats received 2 implants: 1 coated implant on one side and an uncoated implant on the contralateral sides (n=3 per formulation, per dose). Peri-implant tissue was evaluated 2 and 14 days after implantation with H&E staining and IHC markers associated with macrophage polarization as well as molecular analysis (qPCR) for inflammatory and healing markers. H&E stains revealed the presence of the coating, blood clots and inflammatory infiltrate at 2 days around all implants. At 14 days, inflammation had receded with more developed connective tissue with fibroblasts, blood vessels in certain doses of coated and uncoated samples with no foreign body giant cells. This study demonstrated that IonL at the appropriate concentration does not significantly interfere with and healing and Ti foreign body response. Results regarding optimal dose and formulation from this study will be applied in future studies using an oral osseointegration model.

Evaluation of oral microbial corrosion on the surface degradation of dental implant materials.

BACKGROUND: Titanium (Ti) dominates as the material of choice for dental implant systems. Recently, titanium-zirconium alloy (TiZr) and zirconia (ZrO2 ) have emerged as alternative materials due to higher mechanical strength and lower corrosion susceptibility. Oral pathogenic bacteria can colonize Ti surfaces, leading to surface degradation, which has yet to be investigated on TiZr and ZrO2 . The aim of this study was to compare in vitro oral bacterial adhesion and subsequent surface degradation on commercial Ti, TiZr, and ZrO2 implants. METHODS: Ti, TiZr, and ZrO2 implants with sandblasted, acid-etched (SLA) surfaces in addition to modified SLA-treated (modSLA) Ti implants (n = 3) were immersed for 30 consecutive days in Streptococcus polyculture. Post-immersion, adherent bacterial count was quantified. Optical microscopy was used to assess qualitative degradation and score Ti-based implants based on degree of surface damage while electrochemical testing quantified corrosion behavior. Analysis of variance followed by post-hoc Tukey test was used to statistically compare quantitative results (α = 0.05). RESULTS: Ti-SLA, Ti-modSLA, and TiZr-SLA implants exhibited localized features characteristic of corrosion attack while ZrO2 -SLA implants experienced minimal changes in surface morphology as compared to non-immersed control. Corrosion features were more numerous on Ti-modSLA implants but smaller in size as compared with those on Ti-SLA and TiZr-SLA implants. No significant differences in corrosion resistance (polarization resistance and corrosion rate) were observed between Ti-SLA, Ti-modSLA, and TiZr-SLA implants. CONCLUSION: TiZr and ZrO2 dental implant surfaces were not more susceptible to colonization and surface degradation by oral Streptococcus species than commercially pure Ti implants.