Inlay & Onlay Restorations (Partial Crowns)

What Are Inlays and Onlays?

Inlays and onlays are restorative treatments that provide a solution between a filling and a crown. They are used when there is not enough healthy tooth structure for a traditional filling but the damage is not severe enough to require a full crown.

What Is the Difference Between Inlay and Onlay?

• Inlay: Similar to a filling, it sits within the cusps (peaks) of the chewing surface.

• Onlay: Extends over one or more cusps, covering a larger portion of the chewing surface.

What Are They Made Of?

Inlays and onlays are made of ceramic or fiber-reinforced composite. The choice of material depends on the opposing tooth (whether natural, composite, or porcelain) to ensure the best compatibility.

Why Are They Preferred?

• Often used after root canal treatment or in teeth with advanced decay where insufficient healthy tooth tissue remains.

• Traditional fillings may fail to create proper contact points with adjacent teeth, leading to food impaction, gum issues, and further decay.

• Since inlays and onlays are fabricated in a dental laboratory, they ensure accurate anatomy, perfect contact with neighboring teeth, and excellent durability against wear and chewing forces.

Lifespan of Inlays & Onlays

Their longevity depends on the material used, the condition of the tooth, chewing forces, oral hygiene habits, and regular dental check-ups. With proper care, inlays and onlays can last for many decades.

Treatment Process

1. First Appointment:

   • The decayed portion is cleaned.

   • Impressions of the prepared tooth and surrounding teeth are taken.

   • A temporary filling is placed, and impressions are sent to the lab.

2. Second Appointment:

   • The temporary filling is removed.

   • The inlay or onlay is tried in, polished, and permanently bonded with special adhesive.

   • The bite is adjusted, and final polishing is completed.

Important: It takes about 2 hours for the adhesive to fully set. During this time, drinking is allowed but eating should be avoided.

Daily Care

No special care is required beyond normal oral hygiene. Regular tooth brushing, flossing, and periodic dental check-ups are sufficient to maintain them.

Advantages of Porcelain Inlays & Onlays

• Highly esthetic and natural-looking

• Long-lasting durability

• Preserve the remaining healthy tooth structure

• Minimal risk of marginal leakage and recurrent decay

• Excellent fit between the tooth and the restoration

Possible Risks

• If contaminated with saliva during bonding, adhesion may fail → strict moisture control is essential.

• Like natural teeth, porcelain inlays and onlays may fracture under excessive force.