Dental implant abutment and prosthetic materials, their surface treatment, and cleaning modalities are important factors for the formation of a peri-implant soft tissue seal and long-term stability of bone around the implant. This study aimed to investigate the influence of a polymeric material surface cleaning method on the surface roughness, water contact angle, and human gingival fibroblasts (HGF) proliferation. Polymeric materials tested: two types of milled polymethylmethacrylate (PMMA-Ker and PMMA-Bre), three-dimensionally (3D) printed polymethylmethacrylate (PMMA-3D), polyetheretherketone (PEEK), and polyetherketoneketone (PEKK). Titanium (Ti) and zirconia oxide ceramics (ZrO-HT) were used as positive controls. A conventional surface cleaning protocol (CCP) was compared to a multi-step research cleaning method (RCP). Application of the RCP method allowed to reduce Sa values in all groups from 0.14–0.28 µm to 0.08–0.17 µm (p < 0.05 in PMMA-Ker and PEEK groups). Moreover, the water contact angle increased in all groups from 74–91° to 83–101° (p < 0.05 in the PEKK group), except ZrO-HT—it was reduced from 98.7 ± 4.5° to 69.9 ± 6.4° (p < 0.05). CCP resulted in higher variability of HGF viability after 48 and 72 h. RCP application led to higher HGF viability in PMMA-3D and PEKK groups after 48 h, but lower for the PMMA-Ker group (p < 0.05). After 72 h, no significant differences in HGF viability between both cleaning methods were observed. It can be concluded that the cleaning method of the polymeric materials affected surface roughness, contact angle, and HGF viability at 48 h.

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Background : Characteristics of prosthetic materials have a huge effect on soft tissue integration around dental implants. It is proven that shape, design, and the microtopography of the surface have an impact on the peri-implant tissue response. However, it is noted that the contamination of the material surface might have a negative effect on cell growth. Therefore various cleaning protocols have been suggested to improve surface biocompatibility and cell proliferation. Aim/Hypothesis : The aim of the study was to compare the impact of two different cleaning methods of prosthetic materials on human gingival fibroblast (HGF) proliferation so as to choose the most effective. The null hypothesis: there is no significant difference between different cleaning of prosthetic materials. Materials and Methods : During the research, all of the materials' (zirconium oxide ceramics (ZrO), titanium (Ti), lithium disilicate glass-ceramics (Emax), polymethylmethacrylate (PMMA) and polyetherketoneketone (Pekkton)) specimens were polished following manufacturer ' s guidelines. Titanium was used as a positive control. Surface roughness (Sa) was assessed using an optical imaging profiler. Specimens were randomly divided into two groups and cleaned differently. Group 1 (cleaning protocol used in clinical practice) was disinfected with "Perform 2%" solution, rinsed with tap water, soaked in isopropyl alcohol and washed in ultrasonic cleaner with distilled water. Group 2 was soaked in "Decon" solution in a laboratory shaker, rinsed with tap water, distilled water and soaked in 96% ethanol. The proliferation of HGF was evaluated three times: after 24 hours, 48 hours and 72 hours. The experiment was repeated three times. Cell viability was measured using a method based on MTT photocolorimetry. Results : Surface roughness (Sa) values were in a range of 0.08-0.19 μm with ZrO being 0.08 μm, PMMA 0.13 μm, Pekkton 0.13 μm, Ti 0.17 μm and Emax 0.18 μm. It was found that after 24 hours mean proliferation of HGF was significantly higher (P = 0.002) in a Group 2 (0.99, SD = 0.34) compared with a Group 1 (0.67, SD = 0.21) (Fig. 1a). After 48 hours there was also a significant difference (P = 0.02) in HGF proliferation between Group 2 (1.10, SD = 0.21) and Group 1 (0.88, SD = 0.36) (Fig. 1b). Debris left after using the second cleaning method is shown in Figure 2. There were no significant differences observed between these groups after 72 hours. Results between different material groups were likewise NO-significant. Conclusions and Clinical Implications : It was observed that different cleaning methods of implant abutments had a significant impact after the first 24 and 48 hours. HGF proliferation was more effective when prosthetic materials were prepared using a thorough multi-step cleaning protocol. The cleaning method used in clinical practice is important because when not prepared properly, implant abutments become contaminated with debris reducing the effect of material characteristics and surface topography on peri-implant tissue health.

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