Inlays/Onlays

Inlays and onlays are custom-made restorations used to repair teeth that have decay or structural damage but do not require a full crown. They are fabricated outside the mouth to precise specifications and then bonded into or onto a prepared tooth to restore shape and function. The approach emphasizes conservation of healthy tooth structure while reinforcing weakened areas.

An inlay fits within the grooves and between the cusps of a tooth without extending over the cusps, while an onlay covers one or more cusps and provides additional protection. Both options fill the gap between direct fillings and full crowns, offering durability and a natural appearance. Because they are made from high-quality materials, they can closely mimic adjacent teeth.

Direct fillings are placed and shaped inside the tooth in a single visit, which makes them suitable for smaller areas of decay but less ideal for larger defects. Crowns require more extensive tooth reduction because they cover the entire visible portion of the tooth, which is necessary when the remaining structure is weak. Inlays and onlays preserve more natural tooth because they require less removal of healthy enamel and dentin than crowns while offering greater strength than large direct fillings.

Compared with large fillings, inlays and onlays distribute biting forces more evenly and reduce the risk of fracture in the remaining tooth. Compared with crowns, they maintain more of the natural tooth anatomy and often provide a better long-term seal at the margins when properly bonded. The choice among these options depends on the extent of damage, tooth location, and long-term restorative goals.

Ceramic and porcelain are commonly used for inlays and onlays because they closely replicate the color and translucency of natural teeth and resist staining. Modern high-strength ceramics provide excellent aesthetics and wear resistance appropriate for posterior restorations when bonded correctly. Metal alloys, such as gold, remain an option for patients who prioritize maximum longevity and strength, particularly in areas where appearance is less critical.

Resin-based composite inlays can be a conservative choice in some situations, offering ease of repair and a lower modulus of elasticity that can be forgiving under load. Each material has trade-offs related to translucency, wear on opposing teeth, and long-term performance, so your dentist will recommend the best option based on tooth position, bite dynamics, and aesthetic priorities. Discussing these factors with your provider helps align the restoration material with your expectations for appearance and function.

Treatment typically begins with a thorough evaluation and imaging to determine the extent of decay or damage and to plan the restoration. The tooth is prepared by removing compromised tissue and shaping the area to accept the inlay or onlay while preserving as much healthy structure as possible. An impression or digital scan is then taken so the laboratory or in-office milling system can fabricate a precisely fitting restoration.

At the final appointment the restoration is tried in, adjusted for fit and bite, and then permanently bonded with a high-strength resin cement to create a durable seal. The dentist will check occlusion and make any minor refinements to ensure comfort and proper function. Many practices use digital workflows to improve accuracy and reduce chair time throughout this process.

With proper care, inlays and onlays can last many years; longevity depends on factors such as oral hygiene, bite forces, and material choice. Daily brushing, flossing, and routine professional cleanings help protect the margins of bonded restorations and reduce the risk of recurrent decay. Avoiding habits that place excessive stress on restorations—like chewing ice or using teeth as tools—also extends service life.

Regular dental checkups allow your provider to monitor the restoration for signs of wear, marginal breakdown, or changes in contact points and surrounding gum tissue. If problems are detected early, minor repairs or adjustments can often prevent more extensive treatment. For patients who grind or clench, a custom nightguard may be recommended to protect both restorations and natural teeth.

The decision between an inlay and an onlay is based on how much of the tooth structure is affected by decay or fracture. An inlay is used when the damage is confined to the central grooves and between cusps without involving the cusp tips themselves, while an onlay is chosen when one or more cusps are compromised and require coverage. Clinicians assess the remaining tooth strength and the need for cusp reinforcement to determine the most conservative, long-lasting option.

Onlays are often preferred when a larger surface area needs restoration or when cusp support will help distribute occlusal forces more evenly. Inlays preserve more natural enamel when the damage is limited, which can benefit tooth longevity. Your dentist will evaluate functional demands, aesthetic considerations, and tooth anatomy before recommending the ideal restoration.

Inlays and onlays are most commonly used on molars and premolars because these teeth endure the greatest chewing forces and have anatomy well suited to indirect restorations. Posterior teeth benefit from the strength and wear resistance of ceramic or metal inlays and onlays, and those materials can be shaded to blend with surrounding dentition. For front teeth, direct composite restorations or veneers are often preferred for conservative aesthetic corrections, though ceramics can be used in select anterior situations when appropriate.

The choice for anterior cases depends on the extent of damage, aesthetic goals, and the health of adjacent enamel and dentin. When aesthetics are paramount, ceramic solutions that match translucency and shade can provide excellent results, but the dentist will weigh functional and visual demands before recommending an indirect restoration for a front tooth. In all cases, preserving natural tooth structure remains a guiding principle.

Accurate impressions or digital scans are essential for creating a restoration that fits precisely and maintains proper contacts and occlusion. Many practices use CAD/CAM technology and in-office milling or partner with specialized dental laboratories to fabricate restorations that match the prepared tooth anatomy closely. A precise fit minimizes cement thickness, reduces microleakage risk, and supports long-term durability.

Proper bonding technique is equally important: clinicians use contemporary adhesive systems and resin cements to create a strong interface between restoration and tooth. Surface treatment of ceramics, careful isolation during bonding, and stepwise polymerization protocols further improve bond reliability. Post-bond checks for seating, contacts, and occlusion help ensure the restoration performs well under normal function.

Potential complications include marginal leakage leading to recurrent decay, fracture or chipping of the restoration, sensitivity after bonding, and changes in fit over time from wear. Early detection through routine examination and radiographs allows clinicians to repair or replace a restoration before more invasive treatment becomes necessary. Proper case selection, material choice, and meticulous bonding technique reduce the likelihood of these issues.

If a restoration chips or fractures, small defects can sometimes be repaired intraorally, while more extensive damage may require replacement. Persistent sensitivity should be evaluated to rule out pulpal involvement or occlusal interference, and appropriate treatment—ranging from desensitizing therapies to endodontic care—will be recommended based on the underlying cause. Regular follow-up with your dentist helps manage risks and maintain the longevity of your restoration.