A large tooth may need to be root-treated and crowned. If there is insufficient tooth left to secure the crown, the root canals can be filled with fibre bridge material. This is hardened with a bright light and then placed back in position. The other root canals are filled in the same way. As the Composite material is built up, a net is added to increase strength. The net is pushed into the Composite and more material added. The Composite is prepared to receive the new crown. The new crown is fitted.