Inlays and onlays are indirect restorations—fabricated outside the mouth in a dental lab—that fit precisely within (inlay) or over one or more cusps (onlay) of a prepared tooth. They offer a middle ground between fillings and crowns, preserving maximum healthy tooth structure while providing enhanced strength and longevity.

Benefits vs. Fillings and Crowns

• Conservation: Remove only decayed portions; preserve healthy enamel and dentin.
• Strength: Lab-processed ceramics or metals exhibit superior fracture resistance compared to direct composites.
• Marginal Integrity: Precise fit reduces microleakage risk.
• Aesthetic Options: All-ceramic (lithium disilicate) blends seamlessly with natural teeth.

Indications

• Moderate Class I–V lesions where direct restorations would compromise cusps.
• Fractured cusps requiring coverage but not full-crown preparation.
• Replacement of old, failing amalgam or composite fillings.
• Patients with high bruxism—ensuring durable materials to withstand occlusal forces.

Materials

1. Porcelain (Lithium Disilicate)

• High translucency and strength (~360–400 MPa flexural).

2. Zirconia

• Exceptional fracture toughness; ideal for high-stress areas.

3. Gold Alloy

• Biocompatible, excellent wear characteristics, and minimal opposing tooth wear.

4. Composite Resin (Lab-Processed)

• Lower cost; less durable than ceramics but more repairable.

Maintenance & Longevity

• • Durability: Ceramic inlays/onlays last 10–15+ years; gold up to 20+ years.

• • Home Care: Brush twice daily, floss interproximally, and use nonabrasive toothpaste.
  • Recall: Six-month check-ups to monitor marginal integrity and tooth health.

Considerations

• • Cost vs. Benefit: Higher upfront cost than direct composites but superior longevity and less likelihood of replacement.

• • Technique Sensitivity: Accurate impressions/scans and cementation protocols are critical for success.
  • Esthetic Zones: All-ceramic options recommended for visible anterior and premolar regions.