Introduction
An indirect composite inlay is an intracoronal restoration made of resin composite outside the mouth – on a model in the laboratory or chairside – and then bonded into the cavity with resin cement. It suits medium to large Class I and II cavities in premolars and molars, where a direct composite is hard to shape and shrinks under high stress. It works only if preparation, isolation and adhesive cementation are right.
Indications, advantages and disadvantages
- Indications: large Class I and II cavities, especially with a wide isthmus or several surfaces (MOD); replacing large amalgams; contacts and anatomy hard to build directly; several restorations in one quadrant; a tooth-coloured option cheaper than ceramic.
- Contraindications: small cavities (direct composite is better); bruxism and heavy occlusal load; deep subgingival margins without enamel (isolation and bonding fail); high caries risk, poor hygiene; weak cusps, which need cusp coverage (onlay).
Main idea: the composite is polymerised before it enters the tooth, so only the thin layer of resin cement shrinks in the cavity.