Why does my crown mounted on my dental implant keep breaking? It is an upper front tooth and was only 4 months old.

10 years ago a porcelain crown & post was installed. It lasted a few years then the natural tooth broke. An implant with porcelain fused to metal crown was installed. 4 years later it developed a horizontal crack. A temporary patch for 1 year was done so my insurance would pay for new one 5 years after it was installed. 4 months after a new one it broke again. My dentist will pay but if it breaks again he will not. He is baffled. He checked my bite and implant. I wear an mouth guard regularly.

Doctor Answers 2

Could be any one of 4 things...

Sorry to hear about you porcelain troubles.

Often times when porcelain breaks it's one of three primary reasons:

1. Bite. While your dentist has checked your bite and it's clear, occasionally we have bruxing (clenching or grinding) habits that are outside the normal range of regular biting and chewing. It's possible now to have a device monitor your bruxisim and "parafunction" overnight while you sleep

2. Material defect. Porcelain fuses to metal crowns are usually strong and durable crowns however, defects in materials or workmanship is a possibility. Because you broke the crown before as well, I suspect your issue might not be a materials or lab issue.

3. Chewing habits!  We rip open a bag of chips with our teeth, chew on ice or bite our nails... it's  all really bad news for teeth and  especially porcelain!

4. Last but not least, case design. Unsupported porcelain that is not in the long axis of the implant is by far much more fragile to regular wear and tear than any other enamel. A size discrepancy between the implant and the crown its supporting, or a higher degree of angulation in the crown to compensate for an intended cosmetic appearance might also be culprits...

I would probably recommend a second opinion from another professional to see if they can figure out why this porcelain keep breaking.

Hope this helps.


Mississauga Dentist
4.8 out of 5 stars 6 reviews

Implants vs natural teeth: Why crowns break.

When you fracture crowns or roots it is normally due to excessive force.  The fact that you have broken crowns and teeth indicate you probably have a habit or occlusal issue.  Implants unlike teeth are rigid and have no movement, teeth have a little give.

If your doctor thinks the bite is perfect you can wear a bruxism appliance to protect the crown.  A neuromuscular Dentist can do special tests to determine objectively where you bite issues may lie.

If you have jaw issues, headaches or migraines I would definitely have thorough bite evaluation.


Ira L Shapira DDS, D,ABDSM, D,AAPM, FICCMO
Chair, Alliance of TMD Organizations
Diplomat, American Academy of Pain Management
Diplomat, American Board of Dental Sleep Medicine
Regent & Fellow, International College of CranioMandibular Orthopedics
Board Eligible, American Academy of CranioFacial Pain
Dental Section Editor, Sleep & Health Journal

Member, American Equilibration Society
Member, Academy of Applied Myofunctional Sciences


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