A porcelain crown is a tooth-shaped cap placed over a damaged tooth, restoring its natural function, strength, and appearance. These custom restorations cover the entire visible portion of a tooth above the gum line, providing protection and improving aesthetics. While durable, porcelain crowns may occasionally require adjustments after placement for optimal comfort and function.
Reasons for Crown Adjustment
Sometimes, a newly placed porcelain crown can feel “high” or uneven when biting, a common issue known as a high bite. This occurs if the crown contacts opposing teeth prematurely or with excessive force, disrupting the natural bite alignment. Such misalignment can lead to discomfort when chewing, temperature sensitivity, or jaw pain and headaches. Minor aesthetic discrepancies, such as slight variations in the crown’s shape or contour, may also necessitate adjustment.
These issues can impact oral comfort and overall bite harmony. An uneven bite places undue stress on specific teeth or jaw joints, potentially leading to long-term problems if left unaddressed. Even subtle sensations of imbalance or irritation often prompt dental professionals to adjust the crown. Ensuring a balanced bite is crucial for distributing chewing forces evenly and maintaining oral health.
The Adjustment Procedure
Adjusting a porcelain crown involves a precise process where a dental professional modifies its surface. The dentist uses specialized dental burs, small, high-speed rotary instruments often coated with fine diamond particles, to remove minute amounts of porcelain. These burs come in various shapes, such as football, tapered, or round, allowing for targeted reduction of specific areas. The procedure begins with the dentist identifying contact points or excess material using articulating paper, which marks the crown when the patient bites down.
After material removal, the adjusted area is meticulously polished to restore its smooth surface. Polishing is a multi-step process involving different grits of abrasive tools, often diamond-coated rubber polishers, to eliminate any roughness created by the burs. This step is crucial to prevent the crown from abrading opposing natural teeth and to reduce plaque accumulation on a rough surface. The entire adjustment and polishing process is quick and performed with minimal discomfort, often without the need for local anesthetic.
Limits of Adjustment
While adjusting porcelain crowns is a common and effective procedure, there are limits to how much material can be removed. Excessive filing can compromise the crown’s structural integrity, potentially weakening it and making it more susceptible to fracture under normal chewing forces. Thinning the porcelain too much might also expose the underlying substructure, such as metal in porcelain-fused-to-metal (PFM) crowns or zirconia in all-ceramic crowns. Exposure of these materials can lead to aesthetic concerns, as they may appear darker or less natural.
Over-filing can also create microscopic flaws or cracks within the porcelain, especially if done with excessive pressure or without adequate water cooling. These microfractures can propagate over time, eventually leading to chipping or complete failure of the crown. Dentists must exercise precision, removing only the minimum amount of material required to achieve proper bite alignment and comfort. Significant alterations are generally not possible without risking the crown’s durability and long-term success.
When Further Action is Needed
Simple filing or adjustment may not be sufficient in all cases where a porcelain crown presents issues. If a crown is ill-fitting, has structural defects like large chips or extensive cracks, or consistently causes pain not resolved with minor adjustments, more significant intervention becomes necessary. These situations often indicate a problem beyond surface-level contouring.
Further action might involve repairing the crown if the damage is localized and minor, such as a small chip that can be bonded. In many instances, however, particularly with persistent issues like decay developing underneath the crown, significant gum recession exposing the tooth root, or the crown becoming loose or falling off, replacement is the more appropriate solution. A new crown ensures proper fit, protection for the underlying tooth, and restoration of full function and aesthetics.