Why Do Crowns and Bridges Fail? Mistakes to Avoid in Restorative Dentistry

prosthodontist west palm beach working on a crown
February 24, 2025

A failed crown or bridge can be frustrating. You expected durability, but now you’re dealing with discomfort, sensitivity, or even a loose restoration. Many patients wonder why their dental work didn’t last as expected. Was it the procedure, daily habits, or something else? Understanding the reasons behind crown and bridge failures helps prevent future issues and ensures long-lasting results. If you’re facing these concerns, learning what went wrong and how to avoid common pitfalls can help protect your smile. 

prosthodontist west palm beach at work

Common Reasons Crowns and Bridges Fail 

1. Cement Failure and Bonding Issues 

The adhesive used to secure crowns and bridges is vital to their longevity. If the cement bond weakens, the restoration can become loose or fall off completely. 

  • Improper Application: If the cement isn’t applied evenly or thoroughly, the bond may not be strong enough to securely hold the crown or bridge. 
  • Saliva Contamination: During the bonding process, moisture interference can compromise adhesion, leading to early failure. 
  • Natural Wear and Tear: Over time, dental cement degrades, requiring periodic reapplication or replacement. 

 

Patients experiencing loosening should seek prompt dental care to prevent bacterial infiltration and decay beneath the restoration.

2. Poor Fit and Marginal Gaps 

A properly fitted crown or bridge should feel seamless. If there’s even a slight gap between the restoration and the tooth, bacteria can sneak in, leading to decay under the crown. Marginal gaps also cause discomfort and increase the risk of loosening. 

  • Improper impressions during the fitting process 
  • Errors in the lab fabrication of the crown or bridge 
  • Natural tooth shifting before permanent placement 

 

Fixing poor fit requires early detection. Regular dental checkups ensure any marginal openings are identified before they become serious problems. 

3. Bite Misalignment and Uneven Pressure 

A crown or bridge should work harmoniously with the rest of your bite. If the bite alignment is off, excessive pressure can cause cracking, loosening, or wear over time. 

  • Teeth grinding (bruxism) worsens uneven pressure 
  • An improperly adjusted bite can lead to jaw discomfort 
  • Stress from an unbalanced bite weakens restorations 

 

Patients who grind their teeth may need a night guard to protect their restorations. A well-fitted crown or bridge should distribute pressure evenly, preventing damage. 

4. Weak Tooth Structure Underneath 

Crowns depend on a solid foundation. If the underlying tooth is weak, the restoration won’t have the necessary support to function properly. 

  • Decay left untreated before placing the crown 
  • Root canal-treated teeth without proper reinforcement 
  • Inadequate tooth preparation before the procedure 

 

Teeth with root canals may require a post and core buildup for additional strength. A prosthodontist can assess whether additional support is needed before placing a crown. 

5. Material Choice and Durability 

Not all crowns and bridges are created equal. The material used affects longevity, strength, and appearance. 

  • Porcelain: Natural-looking but more prone to chipping 
  • Metal and Gold Alloys: Extremely durable but less aesthetic 
  • Zirconia: Strong, aesthetic, and resistant to wear 

 

Choosing the right material depends on bite force, aesthetic goals, and function. Discussing options with a prosthodontist ensures the best choice for long-term success. 

prosthodontist west palm beach holding a crown model

How Maintenance Affects Crown and Bridge Longevity 

1. Teeth Grinding and Clenching (Bruxism) 

Excessive grinding or clenching places unnecessary stress on crowns and bridges, leading to fractures, loosening, or wear over time. 

  • Nighttime Bruxism: Many people grind their teeth unconsciously while sleeping, which can accelerate damage to restorations. 
  • Stress-Related Clenching: Chronic stress can cause jaw tension and excessive pressure on crowns and bridges. 
  • Preventative Measures: Wearing a custom night guard can help protect restorations from the effects of grinding. 

 

Addressing bruxism early can extend the lifespan of crowns and bridges while preventing additional dental complications. 

2. Poor Oral Hygiene and Plaque Buildup 

Crowns and bridges need regular cleaning, just like natural teeth. Bacteria can accumulate at the gumline, leading to decay or gum disease that weakens the support structure. 

  • Floss around restorations daily 
  • Use antibacterial mouthwash to reduce plaque buildup 

 

Regular professional cleanings also help extend the life of crowns and bridges by preventing underlying issues. 

3. Chewing Hard or Sticky Foods 

Certain foods put extra stress on restorations, causing fractures or dislodging them completely. 

  • Hard candies, ice, and popcorn kernels can crack crowns 
  • Sticky foods like caramel or gum may loosen them 
  • Nuts and hard bread can exert excessive pressure 

 

Being mindful of eating habits protects dental work from unnecessary damage. 

Recognizing Early Signs of Failure 

Being aware of potential warning signs allows for early intervention, saving time, money, and discomfort. 

1. Tooth Sensitivity or Pain

A properly fitted crown or bridge should feel comfortable. Persistent pain or sensitivity can indicate an issue that needs immediate attention. Pay attention to: 

  • Sensitivity to hot or cold: This may suggest nerve irritation or decay developing beneath the restoration. 
  • Pain when biting down: Uneven pressure or a misaligned bite can cause strain, leading to discomfort. 
  • A dull ache in the restored tooth: This could mean an underlying infection, decay, or problems with the tooth’s nerve. 

 

Ignoring these symptoms could lead to more serious complications, such as infections or the need for root canal treatment. 

2. Visible Cracks or Chips

Even minor fractures compromise the strength of crowns and bridges. Over time, these small imperfections can expand, making the restoration more prone to complete failure. Chips in porcelain crowns expose the underlying structure, making it more vulnerable to additional wear and breakage. Addressing minor cracks early prevents larger problems from developing. 

3. Loose or Wobbly Restorations

If a crown or bridge starts to feel loose, it could indicate cement failure or deterioration of the supporting tooth. A loose restoration allows bacteria to enter, leading to decay or infection. Ignoring the problem increases the risk of total detachment, requiring more extensive repairs or even replacement. If movement is noticed, seeking prompt dental care ensures the restoration remains secure and functional. 

Knowing when to see a dentist helps prevent full restoration failure. 

prosthodontist west palm beach discussing options with patient

Considering Crowns and Bridges? Consult a Prosthodontist in West Palm Beach 

If you’ve had a failed crown or bridge or are considering a new restoration, expert care makes all the difference. Palm Beach Dental Specialists provides precision-crafted crowns and bridges designed for durability and comfort. Schedule an appointment today for long-lasting, expertly fitted dental restorations.