Human Gingival Epithelial Growth In Vitro on a Polymer‐Infiltrated Ceramic Network Restorative Material

Abstract

Purpose: To investigate the growth of primary human gingival epithelial (HGE) cells on polymer-infiltrated ceramic network (PICN) material (Vita Enamic) with different surface roughnesses. Materials and Methods: PICN material specimens were polished with either silica carbide paper (grit-polished) or the manufacturer's polishing wheels (wheel-polished), and the surface roughness (R a ) measured. HGE cells were seeded and grown for 1, 3, or 6 days. Growth on tissue culture plastic was used as a control. Non-linear regression analysis was used to examine the effect of surface roughness on cell growth. Results: HGE cell growth on tissue culture plastic fitted an exponential growth model over the 6-day experimental period (R 2 = 0.966). Through day 6, cell density on PICN decreased with increasing surface roughness, with a fit to an exponential decay model (R 2 = 0.666). A threshold R a value of 0.254 µm (95% CI 0.177-0.332) was determined as an upper limit for exponential growth. Cell growth was greatest on the group of specimens with R a value below 0.127µm. Specimens polished by the manufacturer's method produced surface roughness of 0.118 µm and below. Conclusions: PICN material polished to a smooth surface (R a < 0.254 µm) resulted in exponential growth of HGE cell growth compared to rough surfaces. Polishing PICN material as smooth as possible (below a R a of 0.127 µm) was found to maximize epithelial cell growth on the PICN material surface. The manufacturer's polishing method achieved a sufficiently smooth surface. These results are contrary to previous research regarding surface roughness of transgingival implant restoration components. The study results suggest that smoother restorative material surfaces could improve peri-implant soft tissue health.

Biological Responses to the Transitional Area of Dental Implants: Material- and Structure-Dependent Responses of Peri-Implant Tissue to Abutments

“…These materials are used as implant abutments after cementing to the prefabricated titanium base with adhesive resin cement. Although little research has been conducted on the soft tissue seal of these new materials, Smallidge et al have reported favorable epithelial cell growth on the PICN surface when PICN has a relatively low surface roughness (Ra < 0.254 µm) [49]. Another recent study reported that the surface roughness of lithium disilicate was smoother than that of PICN after the same polishing process with 6 µm diamond slurry, and the surface roughness of both of materials was unaffected by the ultrasonic scaling procedure [50].…”

The impact of surface alteration on epithelial tissue attachment after the mechanical cleaning of titanium or zirconia surface

“…The widespread distribution of epithelial cells enhanced the tendency of epithelial tissue to adhere to the implant. Rough surface not only make inferior epithelial attachment, but also it may increase the risk of biofilm and bacterial adherence …”