Growth factors in oral and maxillofacial surgery: potentials and challenges

in cartilage regeneration in the temporomandibular joint, although those are somehow effective for a variety of cells 2. Despite such promising clinical successes of GFs for tissue regeneration, controversies still hound their clinical use for tissue regeneration of the oral and maxillofacial area. The biggest debate deals with the oncogenic potential of GFs. Many tumors including malignancies developing in the oral and maxillofacial area have already been proven to over-express the aforementioned GFs such as TGF-β, BMPs, etc., which are ironically beneficial for tissue regeneration when expressed in adequate amount in tissue. For the clinical trial of GF, supraphysiological doses are required for effective tissue regeneration but increase the risk of tumor development. Unfortunately, the optimum concentration and appropriate timing for administering GF are not fully established, which may be crucial for successful clinical outcome without side effects such as tumor development. Biologically, GFs usually react to each other in a very delicate and sophisticated manner, exchanging feedbacks from the responding cells and tissues. Therefore, GFs often have biphasic feature depending on the condition of the tissue. For example, unexpected delayed tissue regeneration may be happening due to the upregulation of GF inhibitor when exogenous GF is too much for the tissue condition. Therefore, in figuring out the proper dose and timing of GFs, more studies are needed to understand the exact mechanisms of the cascades of GFs when the target tissue is regenerated. In addition, a single dose of exogenous protein is well known not to induce a biological response adequately in compromised tissue conditions 1,2. As discussed by Ripamonti et al. 7 , there is much to discover about growth-signaling molecules in tissue, with unexplained differences between animal and human models. Therefore, blind faith in using GFs for target tissue regeneration should be avoided, and more meticulous considerations should consequently be endorsed prior to GF use. A growth factor (GF) is a naturally occurring substance capable of stimulating cellular growth, proliferation, and cellular differentiation, one of the key factors for tissue regeneration. Usually, it is a protein or a steroid hormone, with unique functions according to the need of the body. For example, bone morphogenic proteins (BMPs) stimulate bone cell differentiation, whereas fibroblast GFs and vascular endothelial GFs trigger blood vessel differentiation (angiogenesis) 1. Various GFs have been tested in the field of oral and maxillofacial surgery to regenerate defective tissues and to enhance the therapeutic effect of …