Adhesive and antimicrobial hydrogels for treatment of peri-implant diseases

Approximately 3 million Americans have dental implants, as a typical tooth treatment for full tooth replacement. Furthermore, there has been a significant growth of dental implant users every year (>15%), with the number of people who use dental implants increasing by more than 500,000 every year. It is estimated that roughly 15 million people throughout the United States have a crown, bridge or implant to replace missing teeth. Costs due to dental replacements were estimated to be $416.3 million in 2016, and as a result of the growing demand, are projected to increase further in the coming years. Recently, the number of patients affected by the peri-implant diseases (PIDs) has also increased dramatically. PIDs are serious problems that plague today's dentistry field, both in terms of therapy and epidemiology. PIDs exist in two forms: (a) peri-implant mucositis (PIM) and (b) peri-implantits (PI). Both diseases are characterized by an inflammatory reaction in the tissues surrounding an implant. PIM is a disease in which the presence of inflammation is confined to the soft tissues surrounding a dental implant, showing no signs of supporting bone loss following the initial bone remodeling. In contrast, PI is an inflammatory reaction with supporting bone loss in the tissues surrounding an implant. The primary method for the nonsurgical treatment of PI involves the mechanical debridement of plaque from the surface of the implant using titanium implant scalers or ultrasonic magnetostrictive implant inserts to improve the health of the peri-implant soft tissue. Currently, there are some commercially available products used in bone regeneration such as INFUSE® and Demineralized Freeze-Dried Bone Allograft. Note: Allograft is used to regenerate bone prior to implantation, making the sentence on adhesion irrelevant. However, both of these products lack antimicrobial activity for the removal of the bacterial load from the surface of implants. As a potential solution to these limitations, we developed a hydrogel based on the natural polymer, gelatin methacrylate (GelMA), (Note: As an adjective, "methacryloyl" should be placed before the noun, "gelatin." Please fix throughout.) and incorporated an antimicrobial peptide (AMP), which is expected to prevent the bacteria in dental implant area. To form these antimicrobial hydrogels, GelMA underwent a photoinitiated radical polymerization (i.e. under UV light exposure with the presence of a photoinitiator) to form a covalently crosslinked network. In addition, highly adhesive and robust mechanical properties were imparted to these hydrogels through the incorporation of Laponite silicate nanoparticles (NPs). Further, cationic AMPs were incorporated into these hydrogel systems to impart antimicrobial properties. We show here, through experimental testing of the adhesive, mechanical, biodegradation, and biocompatibility properties that these hydrogels demonstrate excellent potential to be used as dental implants for PIDs. The prepared nanocomposite hydrogels will be injected to the cavity between implant and native tissue. Then the hydrogels will be crosslinked using visible dental curing light to regenerate the bones.