Inlays and onlays are conservative, indirect dental restorations used to repair teeth with moderate damage or decay—offering a durable, esthetic, and tooth-preserving alternative to full crowns. Thanks to advances in CAD/CAM technology and dental milling machines, inlays and onlays can now be designed and fabricated with extreme precision, often within a single dental visit.
An inlay is a custom-made restoration that fits within the cusps of a tooth, typically used for small to moderate cavities in molars and premolars.
An onlay covers one or more cusps of a tooth and is used when damage is more extensive but does not require a full crown.
Both restorations are bonded to the tooth and restore both function and aesthetics.
• Tooth-Conserving: Preserves more natural tooth structure than a crown.
• Durable: With proper bonding, these restorations can last 10–15 years or more.
• Aesthetic: Tooth-colored materials blend seamlessly with natural teeth.
• Precise Fit: CAD/CAM fabrication ensures micrometric accuracy.
• Biocompatible Materials: Suitable for patients with metal allergies.
Modern inlays and onlays are fabricated using various advanced dental materials:
Material | Features & Use Cases |
|---|---|
| Lithium Disilicate (e.g., IPS e.max) | High translucency, ideal for esthetic zones |
| Zirconia (Y-TZP) | Extremely strong, used for high-load-bearing areas |
| Hybrid Ceramics (e.g., VITA Enamic) | Combines flexibility of composite with strength of ceramic |
| Resin Composite Blocks | Cost-effective and easy to mill, often used for temporaries or minimally loaded areas |
| Gold Alloys (less common) | Excellent fit and longevity, but esthetically outdated |
1. Digital Impression: Taken using intraoral scanners (e.g., Primescan, TRIOS).
2. CAD Design: Restoration is digitally designed to fit the prepared cavity.
3. CAM Milling: Material block is milled in a chairside or lab-based dental milling machine.
4. Post-processing: Includes crystallization (if lithium disilicate), staining, glazing, or polishing.
5. Cementation: Bonded using resin-based cements for durability and marginal seal.
• imes-icore CORiTEC series
• Planmeca PlanCAD / PlanMill
• vhf Z4 / N4+
• Roland DWX-4/52
Replacement of large or failed fillings
• Fractured or worn posterior teeth with intact tooth walls
• Endodontically treated teeth needing structural reinforcement
• Cases where a full crown is too invasive
Restoration Type | Invasiveness | Strength | Aesthetics | Indicated For |
|---|---|---|---|---|
| Direct Composite | Low | Moderate | Good | Small cavities |
| Inlay | Moderate | High | Excellent | Moderate tooth loss |
| Onlay | Moderate | Very High | Excellent | Cusp replacement needed |
| Crown | High | Maximal | Very Good | Extensive tooth loss or fracture |
• One-visit dentistry with chairside systems
• No need for temporary restorations
• Minimized human error through digital workflows
• Optimal occlusion and contact points
• Superior long-term performance with modern materials
• Requires adequate remaining tooth structure
• Technique-sensitive bonding procedure
• Not suitable if decay extends too far subgingivally
• Initial investment for CAD/CAM systems is high
• AI-assisted margin detection for more accurate preparation design
• Ultra-fast sintering of zirconia for same-day posterior onlays
• 3D-printed indirect restorations for cost-effective chairside alternatives
• Bioactive and antibacterial materials for enhanced clinical outcomes
Inlays and onlays represent the perfect balance between conservative dentistry and modern digital fabrication. With CAD/CAM technology and high-performance materials like lithium disilicate and zirconia, these restorations provide unmatched precision, function, and esthetics. As digital workflows evolve, inlays and onlays will continue to offer patients durable, natural-looking, and minimally invasive treatment options.