Titanium particles in peri-implantitis: distribution, pathogenesis and prospects

Abstract

Peri-implantitis is one of the most important biological complications in the field of oral implantology. Identifying the causative factors of peri-implant inflammation and osteolysis is crucial for the disease's prevention and treatment. The underlying risk factors and detailed pathogenesis of peri-implantitis remain to be elucidated. Titanium-based implants as the most widely used implant inevitably release titanium particles into the surrounding tissue. Notably, the concentration of titanium particles increases significantly at peri-implantitis sites, suggesting titanium particles as a potential risk factor for the condition. Previous studies have indicated that titanium particles can induce peripheral osteolysis and foster the development of aseptic osteoarthritis in orthopedic joint replacement. However, it remains unconfirmed whether this phenomenon also triggers inflammation and bone resorption in peri-implant tissues. This review summarizes the distribution of titanium particles around the implant, the potential roles in peri-implantitis and the prevalent prevention strategies, which expects to provide new directions for the study of the pathogenesis and treatment of peri-implantitis.

Fig. 1

The outline of this review. First, we clarified the causes of the release of titanium particles around the implant and the distribution patterns of titanium particles. Then, we analyzed the changes of the distribution of titanium particles at peri-implantitis site, and summarized the possible mechanism of titanium particles in promoting the development of inflammation and existing prevention and treatment strategies. Finally, we conclude and project future research prospects in this field

Fig. 2

The release of titanium particles in the peri-implant environment. In the preparation stage, the wear of the drill bit and the heat generated during the drilling process release some metal particles. In the stage of implantation, the friction between the implant and bone surface, local stress and other factors lead to further release of titanium particles. In the stage of long-term maintenance of the implant, local wear, micro-movement and micro-gap, chemical corrosion and plaque biofilm interaction contribute to the continuous release of titanium particles

Fig. 3

Possible role of titanium particles in the development of inflammation. Foreign body reaction: The presence of titanium particles can induce body foreign body reaction, macrophages phagocytize titanium particles, polarize to M1 type, release pro-inflammatory factors, and induce cell DNA damage; Epigenetics: Titanium and titanium oxides can affect the methylation level of cellular DNA cytosine-5MC by regulating the expression of DNA Class A transferase (DNMT), and subsequently affect the inflammatory response; Signaling pathway: Titanium particles can affect the development of inflammation through a variety of signaling pathways, and regulate NF-κB signaling pathway to affect inflammation by regulating the ratio of RANKL/OPG and affecting the expression of TLR protein family. Wnt/β-catenin signaling pathway is a negative feedback regulatory pathway of titanium-induced inflammation, which can inhibit the NLRP3 inflammasome induced by titanium particles, inhibit inflammation and osteolysis. microbiome: Bacterial corrosion can promote the release of titanium particles, and the combined stimulation of titanium particles and bacteria can promote the expression of inflammation in the tissues around the implant. Others: Oxidative stress, autophagy and other factors may also contribute to the inflammation induced by titanium particles

Fig. 4

Possible solutions of the influence of titanium particles. Inhibit the release of titanium particles: the implant surface is modified by electrospinning, alkali thermal method and other technologies, so that the implant shows a coating film to inhibit the release of titanium particles; Use titanium zirconium, titanium copper and other alloy implants, improve implant materials, zirconium, tantalum, cobalt, chromium, molybdenum and other metal implants and PEEK composite polymer material implants; Inhibition of proinflammatory effect of titanium particles: by indicating modified loaded antibacterial and anti-inflammatory drugs, local injection, local placement of biofilm and other methods