**4. Discussion**

Various tissue induction techniques have been studied and developed in plastic and maxillo-facial surgery. In facial rejuvenation, the most relevant tissue inducers appear to be Nd:YAG laser, trophic lipofilling, mechanostimulation and radiofrequency. Regarding bone induction in maxillo-facial surgery for acquired or congenital defects, the inducers with a proven efficacy are the PRF and the reinjection of bone stem cells. The use of osteotensors should be more carefully studied before being added to the therapeutic arsenal of maxillo-facial surgeons. Many other induction methods are known, but their efficacy has not yet been proved in the plastic and maxillo-facial surgery field [1–15]. Radiofrequency and the plasma (a physical agent) are for example being assessed in non-surgical blepharoplasty. The authors have identified and resumed two main tissue induction mechanisms that act directly and indirectly (**Figures 2** and **3**).

### **5. Conclusions**

Tissue induction allows collagen self-production leading to tissue regeneration. Many techniques can be used for tissue induction that represent an additional tool in the therapeutic arsenal available to plastic and maxillofacial surgeons to improve patient management.

#### **Figure 2.**

*Activation of fibroblast via PRP after releasing of TGF, EGF, VEGF and FGF thanks to the PDGF. Activation of fibroblast via luminous energy by activation of fibroblastic chromophore and increase synthesis of FGF by macrophages. The peak of efficiency is reached with a wave length including 680 and 840 nm.*

#### **Figure 3.**

*Tissular lesion of the skin: wound healing process, releasing of growth factors and activation of fibroblasts and collagen synthesis.*

*Tissue Induction in Plastic and Maxillo-Facial Surgery DOI: http://dx.doi.org/10.5772/intechopen.109088*
