A dental crown is a custom-made cap designed to restore a damaged tooth by fully encasing the remaining structure, providing strength, and improving appearance. Although the restoration is permanently bonded to the tooth, minor modifications are often necessary after placement. Yes, a dental crown can be adjusted after it has been cemented to ensure it functions comfortably and correctly within the mouth’s system of biting and chewing.
Common Reasons Crowns Require Post-Placement Adjustment
Adjustments frequently stem from issues related to how the restoration interacts with opposing teeth, a concept known as occlusion. A common complaint is that the crown feels “too high,” making premature contact when biting down. This causes discomfort and uneven pressure across the jaw, potentially leading to sensitivity in the crowned tooth or jaw joint issues.
Problems also arise where the crown meets the gum tissue. Rough or poorly contoured edges can irritate the gums, potentially leading to inflammation or recession over time. Correcting these fit issues is important to prevent food from getting trapped, which can increase the risk of plaque buildup and decay at the margin.
The Procedure: How Crowns Are Shaved and Material Constraints
Adjusting a permanent crown involves the removal of material using specialized tools. The procedure typically uses high-speed handpieces equipped with fine diamond burs to precisely grind down the surface. Dentists use articulating paper, which leaves colored marks, to identify high spots or areas of excessive contact that need reduction.
A significant constraint in this process is the thickness of the crown material itself. Removing too much material weakens the structure, even for strong ceramic crowns like monolithic zirconia. For porcelain-fused-to-metal crowns, excessive grinding can expose the underlying metal framework, which is aesthetically undesirable and may compromise the bond.
Ceramic materials like porcelain and zirconia are finished with a smooth glaze layer to prevent wear on opposing natural teeth and resist staining. When a crown is adjusted, this protective glaze is removed. If the adjusted surface is not polished back to a high-gloss finish, the resulting rough texture can increase wear on the opposing tooth’s enamel and make the crown susceptible to discoloration.
Maintaining structural integrity is a consideration during adjustment. Monolithic zirconia crowns can maintain sufficient strength even when reduced to approximately 0.5 mm in specific areas. Grinding zirconia must be done with water cooling to prevent overheating, which weakens the material and increases the risk of fracture. The hardness of zirconia also makes it more difficult to modify compared to traditional porcelain, requiring precise techniques.
When Modification is Insufficient: Seeking Replacement
While minor adjustments can resolve common issues, there are specific scenarios where shaving the crown is not a viable long-term fix. If the crown’s fit is severely inaccurate, such as having widely open margins that fail to seal the underlying tooth structure, the restoration must be replaced. Open margins allow oral fluids and bacteria to seep underneath the crown, leading to decay of the tooth beneath and potential failure.
A major aesthetic issue, such as a significant color mismatch or a bulky shape requiring excessive material removal, is another reason replacement may be necessary. Attempting to correct severe misalignment by grinding down the crown too much risks compromising structural integrity or exposing a metal substructure. In these cases, the crown must be removed, a new impression taken, and an entirely new restoration fabricated to ensure proper function and seal.