Post Title

Purpose: The aim of this study was to investigate the biocompatibility of AgNPs-doped

Ti6Al4V surfaces, by evaluating the viability and proliferation rate of human gingival

fibroblasts (HGF) -as dominant cells of peri-implant soft tissues- seeded on the modified

surfaces. Materials and Methods: AgNPs of 8 and 30nm size distributions were incorporated

onto Ti6Al4V specimen surfaces by electrochemical deposition, using colloid silver

dispersions with increasing AgNP concentrations of 100, 200 and 300 ppm. One control and

six experimental groups were included in the study: (i) Control (Ti6Al4V), (ii) 8 nm/100

ppm, (iii) 8 nm/200 ppm, (iv) 8 nm/300 ppm, (v) 30 nm/100 ppm, (vi) 30 nm/200 ppm, (vii)

30 nm/300 ppm. Human Gingival Fibroblasts (HGF) cell primary cultures were isolated from

periodontal-healthy donor patients. AgNP-doped Ti-6Al-4V specimens’ cytotoxicity against

HGF was assessed by the MTT and BrdU assay tests. Calcein AM and Ethidium Homodimer-

EthD1 fluorescent stains were used to determine live and dead cells. HGFs’ morphology and

attachment properties were determined by means of SEM. Results: EDX analysis confirmed

the presence of AgNPs on the specimens. MTT revealed that cells seeded on AgNPs

specimen discs of both tested sizes and all concentrations presented a decreased cellular

metabolic activity compared to the cells seeded on the control discs. All concentrations of

AgNPs of both sizes affected cell proliferation rate compared to the control group, as

revealed by the BrdU assay. Overall, cytotoxicity of the modified Ti6Al4V surfaces depended

on cell exposure time. Observation by confocal microscopy confirmed the results of MTT

and BrdU assay tests. Specifically, most cells remained alive throughout the 72h culture

period. SEM microphotographs revealed that adjacent cells form bonds with each other,

creating confluent layers of conjugated cells. Conclusions: The findings of the present study

indicate that Ti6Al4V surfaces modified with 8 nm and 30 nm AgNPs at concentrations of

100 ppm, 200 ppm, and 300 ppm do not produce any serious cytotoxicity to HGFs. The

initial arrest of HGFs proliferation rate was recovered at 72 h. These results, in combination

with those of the same research group, on the antibacterial activity against common

periodontal pathogens, suggest that AgNP-doped Ti6Al4V surfaces are potential candidates

for use in implant abutments for preventing peri-implant diseases.

Keywords: biocompatibility, dental implants, gingival fibroblasts, peri-implant disease, silver nanoparticles, soft tissue inflammation