Core build-up materials are used when there is not enough healthy tooth left for proper crown placement. Building up the core of the tooth with resin or plastic composites allows for better retention of the crown and reduced sensitivity while strengthening the tooth itself. Composition of core build-up materials should be close to that of dentin. Core build-up materials may be light-cured, self-cured or dual cured. A benefit of dual cure is the assurance of complete curing even in areas that may be hard to reach for the curing light. Curing times vary but are often completed within 5 minutes. Vendors often offer a compatible natural or opaque shade as well as a contrasting color for easy core identification. For easy application, many vendors offer auto-mix syringes with needle tips for perfect placement, many of these are self-adhesive, however be sure to inquire whether a bonding agent is needed. There are a multitude of core build-up products on the market, research and choose the product that will best fit in with your needs.