Titanium dental implant surface micromorphology optimization

Abstract

The purpose of this investigation was to create an acid-etched implant surface that is similar to that created by sandblasting combined with acid etching and to compare it with the surfaces of various commercially available screw-type implants. Titanium grade 5 disks were machined in preparation for acid etching. Tests were carried out using different acids and combinations of them with varying time exposures. All etched surfaces were scanned with an electron microscope, and digital images were created for visual evaluation and description of the surfaces. The etched surfaces were evaluated for surface morphology (combination of microroughness and waviness); the surface most like the sandblasted/acid-etched surface was best obtained with a combination of sulfuric and hydrochloric acids. The etched titanium disks were fixed in acrylic resin (2 were cut and polished and 2 were scored and fractured) and the surface profile was examined. In the second part of the investigation, 28 screw-shaped implants that were manufactured from commercially available titanium grade 5 were selected and divided into 2 groups: 3 implants were used as controls (machined surface), and 25 implants were processed using the preferred etching method determined in the first part of the investigation. Magnifications of 27, 200, and 2000 were used to analyze the first 2 consecutive crests of threads, flanks, and root of threads of each implant with the treated surface. A 3-dimensional optical interferometer was used to characterize the surface roughness of both control and test groups. Three screws were selected from each group and measured at 9 sites: 3 measurements each on the crest, root, and flank of the threads. To describe the surface roughness in numbers, the following parameters were used: the average height deviation (Sa), the developed interfacial area ratio (Sdr), the fastest decay autocorrelation length (Sal), and the density of summits (Sds). In addition, in a third experiment, the surfaces of 5 commercially available screw-type implants and the experimental ones were analyzed and compared. It was concluded that the new experimental acid-etched titanium surface had the features of a roughened titanium surface, with glossily microroughness and large waviness. In general, the experimental surface was significantly rougher than the selected commercially available implants and similar to a sandblasted/acid-etched surface (top Sa: 2.08 +/- 0.36 microm, Sdr: 1.34 +/- 0.3 microm, valleys: 1.16 +/- 0.1 microm and 0.68 +/- 0.1 microm, flanks: 2.24 +/- 0.8 microm and 1.27 +/- 0.1 microm, respectively).