Filling, ceramic onlay or crown: how is the choice made?
The amount and position of healthy tooth, the bite and any crack matter more than choosing a restoration by name.
4 October 2026 · 7 min read · Clinically reviewed by Dr Sundeep Solanki, GDC 212282
A filling repairs a local defect directly. An onlay can cover one or more weakened cusps while preserving other sound walls. A crown surrounds most of the visible tooth. The soundest choice is the least extensive restoration that can protect the tooth predictably.
When a filling may be enough
- The defect is small or moderate
- Strong walls and cusps remain
- The biting load can be restored safely
- There is no crack pattern needing broader protection
When an onlay enters the discussion
An onlay can reinforce a heavily restored back tooth or replace a missing cusp without preparing every surface for a crown. It still depends on a sound, treatable tooth and enough suitable structure for bonding.
When a crown may be more predictable
A crown may be considered where damage, cracks or previous treatment leave too little reliable tooth for a more conservative restoration. Root canal treatment does not automatically mean a crown in every case, but back teeth often need protection from fracture.
This article is general information, not personal dental advice. Treatment suitability is assessed individually at consultation.