An onlay is an indirect restoration that rebuilds a defect and covers one or more tooth cusps. It may be considered when a filling alone does not provide the desired protection but a suitable partial-coverage design can preserve useful tooth structure. Not every heavily filled tooth is an onlay candidate, and an onlay is not automatically a more conservative choice if the remaining surfaces cannot support it.
At Cookstown Dental Centre, we assess the walls, cusps, cracks, margins, and bite before discussing the design. The recommendation should explain which parts need coverage and why. We compare the option with a direct restoration or crown as appropriate, including preparation, material, appointments, and maintenance. The final choice follows the actual tooth rather than a general preference for the least or most coverage.