This document discusses various types of skin substitutes that can be used as temporary or permanent replacements for skin, including biological, synthetic, and bio-synthetic options. It provides details on human allograft skin, noting that it expresses class-2 antigens and is typically rejected within 2-3 weeks but rejection can be decreased through various treatments. The document also discusses the use of autografts with allografts and shows pictures demonstrating the application and results of using amnion grafts on wounds. It provides an overview of Integra, a bio-synthetic skin substitute, explaining its inner biodegradable membrane and outer silicone layer and how it integrates with the body over time.