COMPARISONS
Full crown vs onlay: when to preserve tooth structure and when to cover it
Choose an onlay when the tooth has intact buccal and lingual walls and you can preserve 60% or more of coronal structure. Choose a full crown when cusps are undermined, the tooth is endodontically treated with significant structural loss, or occlusal forces exceed what a parti...
THE BOTTOM LINE
Choose an onlay when the tooth has intact buccal and lingual walls and you can preserve 60% or more of coronal structure. Choose a full crown when cusps are undermined, the tooth is endodontically treated with significant structural loss, or occlusal forces exceed what a partial restoration can handle. Onlays preserve enamel; crowns rebuild it.
SIDE BY SIDE
Onlay (partial-coverage) vs Full crown (full-coverage)
| Consideration | Onlay (partial-coverage) | Full crown (full-coverage) |
|---|---|---|
| Tooth structure removed | Minimal: typically 0.5-1.5mm occlusal reduction over involved cusps only | Significant: 1.5-2mm circumferential plus 1.5-2mm occlusal |
| Ideal indication | Cusp-capping repair on a vital tooth with intact axial walls | Endo-treated tooth, fractured cusps, or post-and-core foundation |
| Margin location | Supragingival or equigingival in most cases | Often subgingival to achieve ferrule and esthetics |
| Material options at Dani | Lithium disilicate (Emax), monolithic zirconia | Monolithic zirconia, layered zirconia, PFM, lithium disilicate |
| Bonding requirement | Adhesive bonding required; isolation critical | Conventional cementation acceptable; bonding optional |
| Chair time at seat | Longer: rubber dam, bonding protocol, occlusal refinement | Shorter: try-in, cement, adjust, polish |
| Retreatment optionality | Easier to convert to a crown later if needed | Terminal restoration; next step is extraction or surgical crown lengthening |
| Typical turnaround at Dani | 5-7 business days in-lab | 5-7 business days in-lab; 7-10 for layered anterior |
| Best for posterior molars with heavy bruxism | false | true |
| Preserves pulpal vitality long-term | true | false |
THE TRADE-OFFS
Where each one earns its place
<p>The decision hinges on remaining tooth structure and how the tooth will load. Onlays are the conservative answer when the biology supports them. Crowns are the right answer when the biology does not.</p><p>Choose an onlay when the tooth is vital, the axial walls are intact, and cusp loss is limited to one or two cusps with sound dentin underneath. Pick lithium disilicate for an onlay when the case is a premolar or first molar with moderate occlusal load and the patient is not a known bruxer. Go with a full crown when the tooth is endodontically treated and missing more than one marginal ridge, when ferrule is compromised, or when the patient presents with documented parafunction.</p><p>Recommend a monolithic zirconia full crown when the case is a second molar with heavy occlusion and esthetics are secondary. Opt for a layered restoration only when the tooth is in the esthetic zone and shade-matching the adjacent dentition is the priority. When the case is borderline, send Dani the intraoral scan and a photo of the prepped tooth; the technician on the case will call back within four hours with a material and coverage recommendation.</p>
<p>Dani Dental fabricates both. The honest read: if your case clearly indicates an onlay and you have a strong adhesive protocol in the operatory, an onlay is the better long-term restoration and we will say so. We are not going to upsell a crown when the tooth does not need one. That said, if you are working without rubber dam isolation or the case has any ferrule question, a full crown is the predictable choice and we would rather build the right restoration than the conservative one.</p><p>Where Dani adds value either direction: the technician on the case is reachable by direct line, the case ships with a margin map and occlusal scheme documented, and our remake rate on crown and bridge sits under 2.5%. If you want a second opinion on coverage before you prep, scan the tooth and send it; we will read it before you pick up the handpiece.</p>
IN PRACTICE
How it plays out on real cases
Worked case examples for this comparison are coming. Send us your case and we will show you exactly how each option would play out.
GO DEEPER
Read the full guide on all procedures
This comparison sits inside a larger procedure. The pillar page covers materials, turnaround, and how we build it to your spec.
REQUEST A DOCTOR KIT
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Send us the case and a named technician will tell you which option they would choose and why. First three cases ship on us, with pre-paid shipping and no contract.