Effect of Calcium Chloride Hydrothermal Treatment of Titanium on Protein, Cellular, and Bacterial Adhesion Properties

Abstract

Topographical modification of the dental implant surface is one of the main topics for the improvement of the material, however, the roughened surface has some risks for peri-implantitis. A hydrothermal treatment (HT) of titanium with calcium chloride solution was reported to improve osseointegration and soft tissue sealing without changing the surface topography; however, its mechanism is unclear. We herewith investigated the interaction between extracellular matrix (ECM) protein and HT titanium. Furthermore, we also clarified the bacterial interaction. We employed two kinds of HT, HT with water (DW-HT) and HT with calcium chloride solution (Ca-HT). As a result, the adsorptions of both laminin-332 and osteopontin onto the Ca-HT surface were enhanced. In contrast, the adsorption of albumin, which was reported to have no cell adhesion capacity, was not influenced by Ca-HT. Osteoblast adhesion onto Ca-HT was also enhanced. Although Ca-HT was reported to enhance both epithelial cell attachment strength and in vivo peri-implant epithelial bonding, the number of epithelial cell attachment was not increased even after HT. Ca-HT had no impact in the adhesion of Streptococcus gordonii. These results suggest that Ca-HT enhances cell adhesion onto titanium without increasing bacterial adhesion, and the improvement of ECM protein adsorption is supposed to contribute to cell adhesion.

The Impact of Dental Implant Surface Modifications on Osseointegration and Biofilm Formation

“…When titanium undergoes a hydrothermal treatment with calcium chloride (CaCl 2 ), osseointegration and the soft tissue seal were improved on the yielded CaCl 2 -treated titanium (Ca-HT) surface [ 19 ]. Meanwhile, the adsorption of laminin-332 and osteopontin and adhesion of osteoblasts on the Ca-HT surface are enhanced [ 19 ]. Moreover, greater attachment of gingival epithelial-like cells and fibroblasts was found on titanium disks with this treatment [ 19 ].…”

“…Similar to the biofilm formation on natural teeth, bacterial colonization occurs within minutes after the implantation procedure and throughout the life cycle of an implant [ 18 ]. The accumulation of the biofilm and specific anaerobic pathogen are known as the primary etiology for the bone loss [ 19 ]. For over a decade, peri-implantitis was treated with mechanical debridement and antimicrobials that were used to treat periodontitis, a gum disease of natural teeth that appeared to have similar phenotypes including biofilm accumulation, signs of soft tissue inflammation, increased depth/bleeding on probing of the gingival pocket area, and destruction of the supporting bones [ 20 , 21 ].…”

Titanium and Protein Adsorption: An Overview of Mechanisms and Effects of Surface Features

“…According to several authors, enhancement of protein adsorption is due to increased surface charge of ion-doped titanium materials [ 31 , 155 ] or the bridging effect of divalent ions [ 155 ]. Some of the most common methods to produce ion-containing titanium surfaces are hydrothermal treatments [ 155 , 156 , 157 , 158 ], which allows to obtain at the same time a nanostructured surface and ionic doping. Higher adsorption of albumin was found on treated cp-Ti with Mg 2+ or Ca 2+ ions with respect to Na + .…”

“…Bridging effect with proteins was confirmed also for trivalent ions such as Fe 3+ [ 162 ], with benefits both in vitro and in vivo. Calcium ions showed further improved protein adsorption, also with respect to other divalent ions such as Mg 2+ and Sr 2+ [ 155 , 156 , 163 ]. Thanks to specific Ca-binding site on some proteins, such as laminin, osteopontin, which is a major non-collagenous bone protein [ 156 ], and BSA [ 163 ], they adsorb in higher amount on Ca-containing surfaces.…”

“…Calcium ions showed further improved protein adsorption, also with respect to other divalent ions such as Mg 2+ and Sr 2+ [ 155 , 156 , 163 ]. Thanks to specific Ca-binding site on some proteins, such as laminin, osteopontin, which is a major non-collagenous bone protein [ 156 ], and BSA [ 163 ], they adsorb in higher amount on Ca-containing surfaces. Protein adsorption and, more important regarding implants, osteointegration were enhanced also by doping of titanium materials with phosphate ions on TNT [ 164 ] or on hydrothermal treated cp-Ti [ 158 ].…”