Mediation of Osseointegration, Osteoimmunology, and Osteoimmunologic Integration by Tregs and Macrophages: A Narrative Review.

Osseointegration is the direct contact between living bone and a dental implant, with supporting evidence confirming the direct connection between bone and titanium, found using an electron microscope. However, the fundamental mechanisms and interconnections between the bone and titanium are not clearly understood. At present, osteoimmunology explores the interaction between bone and immune cells not only in the medical field but also in dentistry. Immunology in bone cell formation has long been a research topic; however, interest in these effects has recently surged. Through subsequent studies, osteoimmune reaction occurs in response to dental implant insertion into the bone and this mechanism portrays more accurate tissue response compared to the traditional term osseointegration. Additionally, osseointegration is a foreign body defense mechanism to protect the implant when bone forms at the contact surface between the dental implant and the alveolar bone. The term "osteoimmunology" refers to the relationship between the immune system and bone tissues. Understanding osteoimmunologic concepts may enable the development of immunomodulatory strategies to improve, maintain, and ultimately restore osseointegration. In order for biocompatible materials such as dental implants to settle and be maintained in the body, it is necessary to understand the complex interrelationships of the bone immune environment, which will enable the development of biomaterials that are more favorable to osteoimmune environments. Therefore, this review presents previous insights into cellular and molecular interactions between bone and the immune system, specifies the roles of T-regulatory cells (Tregs) and macrophages, and demonstrates their potential for translational applications worldwide.