Gingival fibroblasts behavior on bioactive zirconia and titanium dental implant surfaces produced by a functionally graded technique

Abstract

Adding a biological apatite layer to the implant surface enhances bone healing around the implant. Objective This study aimed to characterize the mechanical properties and test human gingival fibroblasts behavior in contact with Zirconia and Titanium bioactive-modified implant materials. Methodology 6 groups were considered: Titanium (Ti6Al4V), Ti6Al4V with 5% HA and 5% ßTCP, Zirconia (YTZP), YTZP with 5% HA and 5% ßTCP. For each group, we produced discs using a novel fabrication method for functionally graded materials, under adequate conditions for etching and grit-blasting to achieve equivalent surface microroughness among the samples. Surface roughness (Ra, Rz), water contact angle, shear bond strength, and Vickers hardness were performed. Human gingival fibroblasts immortalized by hTERT gene from the fourth passage, were seeded on discs for 14 days. Cell viability and proliferation were assessed using a resazurin-based method, and cellular adhesion and morphology using field emission gun scanning electron microscopy (FEG-SEM). After 3 days of culture, images of fluorescent nucleic acid stain were collected by confocal laser scanning microscopy (CLSM). Results Results were presented as mean ± standard deviation (SD). We compared groups using one-way ANOVA with Tukey’s post-hoc test, and significance level was set at p<0.05. After 14 days of culture, cell viability and proliferation were significantly higher in YTZP group than in other groups (p<0.05). Samples of YTZP-ßTCP presented significantly higher wettability (p<0.05); yet, we observed no improvement in cell behavior on this group. Fibroblast spreading and surface density were more evident on YTZP specimens. Adding calcium-phosphate bioactive did not alter the tested mechanical properties; however, Ti6Al4V material shear bond strength was statistically higher than other groups (p<0.05). Conclusion Adding bioactive materials did not improve soft-tissue cell behavior. When compared to other zirconia and titanium groups, pure zirconia surface improved adhesion, viability and proliferation of fibroblasts. Cell behavior seems to depend on surface chemical composition rather than on surface roughness.

The integration of peri-implant soft tissues around zirconia abutments: Challenges and strategies

“… Before: 78.31°; 0.05 ± 0.01 μm [ 118 ] After: 43.71° 13 Y-TZP containing 5% HA or 5% β-TCP Bioactive modified HGFs in vitro HGF adhesion, viability, and proliferation were decreased. Before: 70.59°; 1.45–1.86 μm [ 121 ] After: 70.82°, 65.04° 14 Y-TZP; NANOZR Coated with silk fibroin in vitro A silk fibroin electrogel coating had sufficient bonding strength The biocompatibility of zirconia was improved. [ 132 ] 15 ZrO 2 Coated with polydopamine (PDA) HGFs in vitro Cell attachment and proliferation were increased; Bacterial adhesion was reduced.…”

“…Bionic surface coatings, such as hydroxyapatite (HA), β-tricalcium phosphate (β-TCP), collagen and chitosan, may promote soft tissue formation around zirconia abutments. However, soft tissues reacted inconsistently towards these coatings [ 46 , [119] , [120] , [121] , [122] , [123] , [124] ] and they gave desirable results on titanium surfaces but not on zirconia [ 121 ]. Biomimetics, silk protein and polydopamine (PDA), have also been investigated to construct surface coatings [ 125 ].…”

Oral Tissue Interactions and Cellular Response to Zirconia Implant-Prosthetic Components: A Critical Review

“…The biological responses performed after the placement of a biomaterial in the oral environment are very important for tissues where there is a need for healing [ 3 , 12 , 13 ]. Surface modifications, functionalization of ZrO 2 , as well as innovations in the base-material can induce individualized cellular responses promoting a better performance of the device once it is implanted [ 9 , 12 , 17 , 70 ]. As a result, intraosseous implants, components for implants and oral prostheses made from ZrO 2 have attracted the attention of researchers and clinicians due to their biocompatibility properties ( Table 2 ).…”

“…Rottmar et al demonstrated that zirconia surfaces had the best performance with regards to fibrinogen adsorption and thrombogenicity [ 15 ]. Furthermore, reports prove zirconia to have an advantage in terms of biological properties with soft peri-implant tissues thereby modulating fibers and cell attachment and behavior with greater effectiveness and biocompatibility [ 16 , 17 ]. Along with the properties mentioned above, zirconia has a low surface energy [ 18 , 19 ], therefore it retains very low amounts of plaque and consequently has less bacterial colonization on its surface.…”

Human Gingival Fibroblast and Osteoblast Behavior on Groove-Milled Zirconia Implant Surfaces

“…Among them, yttria-stabilized polycrystalline tetragonal zirconia (YTZP) is the most popular because of its mechanical properties and similarity to titanium. In addition, due to its metal-free properties, coupled with its aesthetic white color and translucency like human teeth, YTZP could be the preferred material for dental implants in the future as an alternative to titanium implants [ 9 , 10 , 11 , 12 , 13 ].…”