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INTRODUCTION: Reducing the healing period after surgical placement of dental implants can facilitate the loading of dental prostheses. AIM: The aim is to compare the osteogenic potential of unmodified titanium disks with titanium disks that were surface-modified or hydrogel-coated. MATERIALS AND METHODOLOGY: One hundred eight titanium disks (Ø6 × 2-mm) were divided into three groups: (1) unmodified titanium as control (Ti-C); (2) sandblasted and acid-etched (Ti-SLA), and (3) coated with tamarind kernel polysaccharide hydrogel grafted with acrylic acid (Ti-TKP-AA). The osteogenic potential and cytotoxic effect of various groups of titanium were compared using human osteoblasts Saos-2. The surface topography of the titanium disks and morphology of osteoblasts grown on disks were investigated by scanning electron microscopy (n = 3). Cell attachment to the disks and actin expression intensity were investigated by confocal imaging (n = 3). Cytotoxicity was quantified by cell viability assay (n = 9). Osteoblast maturation was determined by alkaline phosphatase assay (n = 9). Cell mineralization was quantified by Alizarin red staining (n = 9). One-way analysis of variance followed by Tukey's multiple comparisons test was used for intergroup comparisons (α= 0.05). RESULTS: The surface modifications on Ti-SLA and Ti-TKP-AA support better morphology and proliferation of osteoblasts than Ti-C (P< 0.001) and significantly higher levels of actin cytoskeleton accumulation (P< 0.0001). Ti-TKP-AA showed a significantly higher maturation rate than Ti-C (P< 0.001). Ti-TKP-AA showed > twofold increased mineralization than Ti-C and Ti-SLA (P< 0.001). CONCLUSIONS: TKP-AA hydrogel-coated titanium promotes faster osteoblast proliferation, maturation, and mineralization than SLA-treated or untreated titanium. These advantages can be explored for achieving early osseointegration and prosthetic loading of titanium dental implants.
RESUMO
STATEMENT OF PROBLEM: Rapid osseointegration between implant and bone tissue for early loading of a prosthesis with sufficient primary stability depends on the surface characteristics of the implant. The development and characterization of suitable surface coatings on dental implants is a major challenge. PURPOSE: The purpose of this in vitro study was to evaluate and compare the osteogenic potential and cytotoxicity of unmodified zirconia, acid-etched zirconia, bioactive glass-coated zirconia, and tamarind kernel polysaccharide with hydrophilic acrylic acid (TKP-AA) hydrogel-coated zirconia. MATERIAL AND METHODS: Thirty-six disks each of unmodified zirconia, acid-etched, 45S5 bioactive glass-coated, and TKP-AA hydrogel-coated zirconia were evaluated for osteogenic potential and cytotoxic effect by using human osteoblast Saos-2 cells. The surface topography of the disks and the morphology of the cells grown on these surfaces were examined by scanning electron microscopy (n=3). The cell attachment was evaluated by confocal imaging (n=3). The cytotoxic effect was evaluated by cell viability assay (n=9). Osteoblast maturation was assessed by alkaline phosphatase assay (n=9) and cell mineralization by alizarin red staining (n=9). ANOVA and Bonferroni multiple comparison post hoc tests were used to evaluate the statistical significance of the intergroup differences in these characteristics (α=.05). RESULTS: The surface modifications resulted in distinct changes in the surface morphology of zirconia disks and the growth of Saos-2 cells. Zirconia disks coated with TKP-AA promoted higher proliferation of osteoblasts compared with unmodified disks (P<.001). Similarly, the surface modifications significantly increased the differentiation of mesenchymal stem cells to osteoblasts as compared with uncoated zirconia (P<.001). However, the rate of differentiation to osteoblasts was similar among the surface modifications. Acid-etched and TKP-AA-coated disks promoted mineralization of osteoblasts to the same extent, except bioactive glass coating, which significantly increased the rate of mineralization (P<.001). CONCLUSIONS: Surface modification of zirconia by acid etching and coating with Bioglass or TKP-AA hydrogel resulted in the improved growth and differentiation of osteoblasts. TKP-AA hydrogel coating promoted the proliferation of osteoblasts, whereas Bioglass coating showed better mineralization. TKP-AA hydrogel coating is a promising candidate for improving the osseointegration of dental implants that warrants further investigation.
