Dental and Orthopedic Applications for Hydrophilic Coatings

I am not going to say this is a hopeless cause, because there could always be that device out there that could benefit from a slippery hydrophilic coating that I have not seen yet. However, if you think about dental and orthopedic applications in relation to hydrophilic coatings and/or lubricious coatings, I am generally not enthusiastic when approached by these companies.

Mainly, what I am thinking about right now are bone screws and plates for bone repair, and dental implants for prosthetic dentistry. To analyze this, I want you to ask yourself what sorts of environmental conditions are these devices exposed to?

Essentially, these are implantable medical devices, so everything I said in my previous article on implantable hydrophilic coatings applies. That is to say that polymeric hydrophilic coatings will degrade or be abraided off during insertion. A hydrophilic coating made from your typical polyurethane, polyacrylic, pvp, or hyaluronan would not have the strength to withstand those shear forces. A research version of a titanium-based hydrophilic coating exists which might be good for this sort of application, except that it has no commercial sales that I can find, and could literally be years or a decade away from commercialization. This also means that I cannot find anything about its mechanical or frictional properties. Thus, for now, we are stuck with polymeric coatings.

Even more strangely, I once

got a call from an entrepreneur seeking to coat a calcium phosphate-based bone void filler with hydrophilic hyaluronan. Unfortunately, he could not tell me why. Everything I know about bone growth into scaffolds tells me this should not be done because if you inhibit clotting in the porous matrix, you can inhibit formation of the fibrin matrix that eventually houses the osteoblasts that will eventually lay down bone. More thought needs to be put into some of these applications.

If instead you are thinking about temporary disposable instruments, like a replaceable tip for a knee scope, or a minimally invasive surgical canula, you may be in luck. Devices that are disposable and not implanted might indeed benefit from a lubricious hydrophilic coating.