Inlays and onlays are used to restore back teeth (premolars and molars) where very large fillings are required, but if placed would not be possible to support the tooth adequately. These teeth may have extensive decay or fractures and may be too damaged to support a basic filling but not sever to need a crown. These inlays and onlays are bonded onto the remaining tooth.
If you are not sure if an inlay or onlay is your solution, it is advisable to book a dental check-up and discuss the options with your dentist prior to any treatment.