| Objective: Good adhesion of soft tissue on implant can improve the success rate of implants. Good adhesionof soft tissue can prevent bacteria and proinflammatory cytokines entering the implant surrondings, it can asa biological barrier protection and stability of bone-implant interface,so it can maintain the stability of theimplant[1]. The micro-implant surface topography can impact the attachment of soft tissue to implant.Thepurpose of this study is to compare the effects of five different titanium surface characteristics on gingivalsoft tissue interface and to find a proper implant neck surface characteristic for the preferable adhesion of thegingival soft tissue.Methods:Titanium surface was processed by electrochemical methods to form four different surfaces,namely the Nano morphology of acid etching group,the micron morphology of electrochemical etchinggroup1and2, the micro or nano morphology of electrochemical etching and acid etching group,the smoothmorphology was used as control group. These five kinds of implants were immediately implanted in themandible of6experimental dogs in a certain order. The dogs were sacrificed respectively after20days and3months, and then the specimens were manufactured and scaned by scanning electron microscope,transmission electron microscope, and light microscope to observe the bonding interface of the gingival withthe implant surface.Results: The gingival epithelium bonded with the implant surface closely. No significant difference wasfound among all groups,after removal of soft tissue, there was no epithelial tissue remaining on implantsurfaces. The collagen fibers in S group adhered and paralleled with the implant surface, and most of thecollagen fibers dehisced and separated from implant surface; and few residual collagen fibers remained onimplant surface. Collagen fibers in other groups were vertical to the implant surfaces. The interface ofgingival tissue and implant surface formed complex micro-nano mosaic structures, and the gingival tissuedehisced less from implant surfaces compared with S group; the collagen fibers remaining on the implantsurface of in the micron group2and the nano-micron group were more than those in the nano group and themicron group1. Under the transmission electron microscope,the junctional epithelium of the smooth groupand nano group could found vacuolar variant at20days, and the epithelial cells was in good condition atthree months, but the cells were not found hemidesmosomes-the base plate structure, its attaching way wasunclear; the cells of micron group1were in good condition and the obvious hemidesmosomes-base platestructure at20days and3months, the cells of the micro group2and nano-micron group were in goodcondition could be seen at20days and3months, hemidesmosome structure could be seen but the base platedid not exist. Under the light microscope,the soft tissue of implant was similar to natural teeth,it couldform gingival epithelium, free gingival,gingival sulcus epithelium and the epithelium and connective tissueadhere to the implant surface at20days. The shape of epithelial cells and nuclear was flat,its axis wasparallel to the surface of the implant, the cells’ number is gradually reduced from coronal to root. Thefollowing connective tissue constitute by a large number of collagen fibers, the capillaries could be seen inthe lamina propria of the attached gingiva,but the capillaries near by the surface of the implant was verylittle,so it was similar to scar tissue. The soft tissue of the smooth group at20days and3months and thenano group at3months were separated from implant surface, the other groups were combined with thesurface closely. Conclusion: The micron and micron-nanometer surface can significantly improve the adhesion of thegingival soft tissue on the implant with the methods of electrochemistry.The micron and micron-nanometersurface is an ideal micro-topography of implant neck. |
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