| Background and ObjectiveCurrently,implant replacement for lost teeth has become the preferred treatment option.The initial biological barrier,the soft tissue around the implant repair,plays a crucial role in the long-term durability of the implant in addition to successful osseointegration.A key element in separating the bone tissue surrounding the implant from the oral environment is the biological sealing of the soft tissues around the neck of the implant prosthesis.Soft tissue sealing includes connective tissue attachment and epithelial attachment,which is mainly attached to the surface of the implant restoration by hemidesmosomes and basal plates.This experiment initially investigated the differences between different implant restoration abutment materials and human gingival epithelial cell hemidesmosomes and screened the abutment materials for easier epithelial attachment.Methods1.The circular sheet polyetheretherketone(PEEK),zirconium dioxide(ZrO2),and pure titanium(Ti)specimens were prepared,sanded,and polished step by step,cleaned,and dried,high temperature and high-pressure sterilized.The surface morphology of each specimen was observed by scanning electron microscope(SEM),the surface roughness was measured by the white light interferometer,and the contact angle was measured by optical contact angle meter.2.The PEEK,ZrO2,and Ti specimens were co-cultured with human gingival fibroblasts,osteoblasts,and human epithelial cells in cell culture plates.SEM was used to observe the early cell adhesion morphology of each group of specimens at 1 d of culture,CCK-8 was used to detect the cell proliferation ability at 1 d,3 d,5 d,and 7 d,and fluorescence microscopy was used to observe the DAPI staining at 1 d,3 d,5 d,and 7 d.3.The mRNA and protein expression levels of Laminin α3,Integrin β4,and Collagen XVII were detected by qRT-PCR and Western blot after adhesion of human gingival epithelial cells to the surface of the three groups of materials at 3 d and 7 d.Results1.SEM observation of all three groups of materials showed a flat and smooth surface morphology.The results of white light interferometry showed that the Ra values of PEEK,ZrO2,and Ti were:95.63 ± 2.06 nm,37.93 ± 3.56 nm,134.2 ± 4.62 nm,respectively,which were statistically significant in the comparison between groups(P<0.05);the Rz values of PEEK,ZrO2 and Ti were:2.42 ± 0.22 nm,0.87 ± 0.1 nm,and 3.77 ± 0.28 nm,with statistically significant comparisons between groups(P<0.05).The water contact angles of PEEK,ZrO2,and Ti detected by the optical contact angle meter were 81.23°±0.91°,82.08°±2.10°,and 80.47°± 1.85°,respectively,and there was no obvious difference between the groups(P>0.05).2.The early adhesion patterns of human gingival fibroblasts(HGF),osteoblasts(OB),and human gingival epithelial cells(HGE)were observed on the surface of the three materials for 1 d by SEM.The results showed that the cells were able to adhere and spread well on the surface of each group.HGF was elongated spindle,long shuttle,or star-shaped,showing typical fibroblast morphology;OB was triangular,shuttle-shaped,and other irregular morphology,with short and thin protrusions visible on the cell surface;HGE was flattened and stretched polygon,and other irregular shapes,showing the typical paving stone pattern.3.CCK-8 results showed that:the absorbance(OD)values of HGF showed that the OD values were no obvious difference for 1 d of cell culture,and the OD values of the PEEK groups were higher than those of the ZrO2 and Ti groups for 5 d of cell culture,which were statistically significant(P<0.05).The OD values of OB rose with the culture period and showed rapid proliferation at 5 d.The OD values were comparable between groups with no obvious difference(P>0.05).The OD values of HGE showed that there was no statistical difference between the groups at 1 d and 3 d,but the results for 5 d and 7 d showed OD values of the PEEK group were significantly higher than those of the ZrO2 and Ti groups,which were statistically significant(P<0.05).4.DAPI staining revealed that blue round or oval nuclei were visible on the surface of all three groups,and the number of blue nuclei increased with culture time.HGF results showed that there was no obvious difference in the comparison between the groups for 1 d culture,and the PEEK groups had more cell adhesion than the ZrO2 and Ti groups for 3 d and 7 d culture,which were statistically significant(P<0.05);OB results showed that there was no statistical difference for 1 d culture,however,at 5 d,and 7 d,the PEEK group had more cell adhesion than the ZrO2 and Ti groups,which was statistically significant(P<0.05);HGE results showed that there was no statistical difference for 1 d culture,and cell adhesion was higher in the 3 d,5 d,and 7 d PEEK groups than in the ZrO2 and Ti groups,which was statistically significant.(P<0.05).5.The expression of genes and proteins related to hemidesmosomes in human gingival epithelial cells on the surfaces of three materials was detected.The qRT-PCR results revealed that the PEEK group had greater mRNA expression levels of Lam 3,Itg 4,and Col 17 than the ZrO2 and Ti groups(P<0.05),and the mRNA expression levels of Lam α3 and Itg β4 were ranked:PEEK groups>ZrO2 groups>Ti groups,whereas the mRNA expression levels of Col 17 were ranked:PEEK groups>Ti groups>ZrO2 groups,which was statistically significant(P<0.05).Western blot analysis revealed that Laminin 3,Integrin 4,and Collagen XVII protein expression was significantly higher in the PEEK groups compared to the ZrO2 and Ti groups.(P<0.05).ConclusionsAll three groups exhibited high cytocompatibility and initial adhesion.In comparison to the ZrO2 and Ti groups,the PEEK group was more favorable to the adhesion and proliferation of human gingival fibroblasts,human gingival epithelial cells,as well as the expression of genes and proteins related to hemidesmosome junctions in human gingival epithelial cells. |
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