A broken dental crown can look like a visible crack line running across the surface, a chipped or missing piece exposing darker tooth underneath, or a crown that has shifted and no longer sits flush with your gumline. Sometimes the damage is obvious. Other times, the only visible clue is a thin hairline fracture you can barely see, a dark line forming where the crown meets your tooth, or a rough edge you notice more with your tongue than your eyes.
Visible Cracks and Chips
The most recognizable sign of a broken crown is a crack running across its surface. These range from tiny craze lines (superficial surface cracks that look like faint scratches) to deeper fractures that split the crown from one side to the other. Craze lines are limited to the outer surface only and are mostly cosmetic. Deeper cracks, sometimes called crown-originating fractures, typically run between the ridges on top of a molar and can extend down toward the root. These deeper fractures often follow a front-to-back pattern and may be hard to see with the naked eye. Dentists use a bright light shone through the tooth (transillumination) or special dyes that seep into crack lines to make them visible.
A chipped crown is easier to spot. You’ll see a piece missing from the biting surface or edge, sometimes exposing the darker natural tooth or metal framework underneath. Porcelain crowns are especially prone to chipping, and the contrast between white porcelain and the material beneath it makes even small chips noticeable. If a large section breaks off, you may be able to feel a sharp or rough edge with your tongue.
A Crown That Has Come Loose or Shifted
Not every broken crown cracks in place. Sometimes the cement bond fails and the crown lifts, tilts, or falls off entirely. A loosened crown often looks slightly raised compared to the teeth around it, or you may notice a gap forming between the crown’s edge and your gumline. When you bite down, the crown may rock or feel unstable. If it falls off completely, you’ll see the prepared tooth stump underneath, which is typically shorter and more cone-shaped than a natural tooth and may appear darker or discolored.
Dark Lines and Discoloration at the Margins
One of the subtler signs of crown damage is a dark line or shadow forming where the crown meets your tooth, right at the gumline. This discoloration happens when the seal between the crown and tooth breaks down, allowing bacteria and staining to seep into the gap. The gum tissue itself may also darken in that area. With metal or porcelain-fused-to-metal crowns, a gray or bluish line at the gum margin can develop over time, though this isn’t always a sign of breakage. The key distinction: if the dark line is new or getting worse, it likely signals a compromised seal rather than normal aging.
What a Broken Crown Feels Like
You may notice the damage by feel before you can see it. A sharp or rough edge that catches your tongue is one of the earliest tip-offs. Beyond texture, a broken crown often produces specific pain patterns that help pinpoint the problem.
Sharp pain when biting down, especially a jolt that hits when you release pressure rather than when you first bite, is a hallmark of a cracked crown or cracked tooth underneath. Temperature sensitivity, like wincing at hot coffee or cold water, suggests the inner layers of your tooth are now exposed through the break. Tenderness in the gum tissue right around the crown, particularly if the gums look red or swollen, points to bacteria getting beneath the damaged seal. Persistent bad breath that doesn’t respond to brushing, a metallic taste, or a dull ache that comes and goes are all additional warning signs.
Signs of Decay Beneath the Crown
Sometimes a crown looks intact on the surface while the real problem is hiding underneath. Decay can develop at the margin where the crown meets your natural tooth, gradually working its way deeper without any visible crack. The clues tend to be indirect: new sensitivity to temperature, soreness in the surrounding gums, bleeding when you brush around the crown, or a faint discoloration at the crown’s edge.
Dentists detect this hidden decay by probing the margins with an instrument to feel for soft spots or gaps, and by taking X-rays that can reveal dark shadows beneath the crown where tooth structure has broken down. This is one reason routine dental visits matter even when a crown looks fine. By the time you can see decay around a crown with your own eyes, it has usually progressed significantly.
What Happens If You Ignore It
A broken crown that goes untreated gives bacteria a direct path to the vulnerable tooth underneath. Infections under a crown often develop slowly and quietly, without the dramatic pain you might expect. Over weeks or months, bacteria can reach the inner pulp of the tooth, causing inflammation that may eventually require a root canal. If the infection progresses further, it can form an abscess, a pocket of pus at the tooth root that causes swelling in the surrounding tissue, bone loss, and in rare cases nerve damage. A tooth that could have been saved with a new crown may eventually need extraction.
What to Do in the Meantime
If your crown cracks, chips, or comes loose, contact your dentist to schedule a repair. While you wait for your appointment, you can take a few steps to protect the exposed tooth. If the crown came off in one piece, clean it gently, apply a small amount of over-the-counter dental cement to the inside, and press it back into place. Hold it with your fingers for about 60 seconds until the cement sets, then clean away any excess with a cotton swab. Dental cement and temporary crown repair kits are available at most pharmacies.
Until you see your dentist, avoid chewing on that side of your mouth. Skip hard, crunchy, or sticky foods that could dislodge a temporary fix or push debris into the exposed area. If you’re experiencing sharp pain, over-the-counter pain relief can help, but persistent or throbbing pain warrants a call to your dentist sooner rather than later. A temporary fix is not a permanent solution. The longer a broken crown stays compromised, the higher the risk of infection or further damage to the tooth underneath.