Microscopical and chemical surface characterization of the gingival portion and connection of an internal hexagon abutment before and after different technical stages of preparation

Aim This study was aimed to assess contaminants on the abutment surface close to the implant-abutment interface and the connection, after common technical protocols. Materials and methods A total of 40 abutments were divided into four groups: control group (abutment removed from the plastic envelop), test group1 (milled), test group2 (milled and polished), test group3 (milled, polished and steamed). Groups were subjected to scanning electron microscope (SEM) analysis. Pollution particles were counted and measured. Mean values and standard deviation (SD) were calculated. To evaluate any difference between groups Wilcoxon Signed Rank Test was conducted. In addition, contaminant chemical characterization was investigated by Energy-dispersive X-ray spectroscopy (EDX). Results Control group presented minimal amount of pollution (mean value of 2.1 spots [SD: 1.66] covering 0.004% of the surface). On the other hand, SEM analysis revealed on the abutment surface a mean value of 115.9 (SD: 32.27), 162 (SD: 21.17), and 32.5 (SD: 9.73) spots, respectively, in Test group 1, 2, and 3. Micro-particles covered the 0.025%, 0.057%, 0.0404% of the surface, respectively, in Test group 1, 2, and 3. On the connection, SEM analysis revealed a mean value of 61.9 (SD: 9.07), 39 (SD: 12.35), 42.1 (SD: 8.59) spots, respectively, in Test group 1, 2, and 3. Micro-particles covered the 0.0774%, 0.0869%, and 0.0392% of the surface, respectively, in Test group 1, 2, and 3. Spots were identified by EDX as micro-particles of lubricant and titanium smear layer. All differences were statistically significant. Conclusions After technical procedures, presence of contaminants on the abutment surface in contact with the peri-implant tissues was confirmed. To prevent that such debris could interfere with biological stability of peri-implant tissues and, thus, enhance the implant-prosthesis integration, different cleaning protocols should be evaluated.