Upgrading teeth with fiberglass posts – invisible, high esthetical composite posts boosted with glass fiber, which have same module of elasticity as teeth, what is important for reducing risk of unequally transfer of pressure and root fracture. Their connection with root canal is 3-4 times better, than connection between canal and metal post, and is needed less subtraction of healthy tissue of teeth, during preparation of root canal. With this kind of posts is allowed esthetical restoration of teeth, in contrast to metal posts.