Cracking Up

Tiny cracks in teeth are common and usually don’t cause problems, but a serious split needs attention.

If you’ve ever had a cracked tooth, you know it isn’t any fun.  The crack can cause sharp pain while you chew, sensitivity to hot and cold foods and drinks, and, in some cases, ongoing pain.  But what causes a tooth to crack, and why does it hurt so much?  “Biting on hard food or objects, faulty or large fillings and grinding your teeth are all causes,” says Dr. Jack McLister, President Elect of the ODA and a dentist who practises in London.  “Lower molars and upper bicuspids are the most common teeth to crack.”  (The lower molars are the bottom back large teeth, and the upper bicuspids are the smaller top teeth that are found just forward of the larger back teeth and just behind the eye teeth.)

Dr. Natalie Dugas is an endodontist in private practice in Sudbury, who regularly treats patients with cracked teeth.  “If the cracks extend through the outer enamel layer of the tooth and progress into the inner dentine layer, pain can develop,” she says.  “This is because the dentine has small tubules (channels) that communicate with the pulp (nerves and blood vessels) of the tooth.  As bacteria from the mouth begin to flow through the crack into the deep layers of the tooth, they can gain access to the pulp, causing it to become inflamed.”


Common symptoms and treatment

A typical symptom is intense sharp pain when chewing that feels like lightning bolts are shooting through the tooth.  “The tooth is also intensely sensitive to temperatures and can throb spontaneously,” notes Dr. Dugas.  “Your dentist can treat cracked teeth with fillings that cover the crack or crowns,” says Dr. McLister.  “But a root canal treatment may be necessary if the crack involves the pulp.”

If your dentist suspects the crack involves the pulp, you may be referred to an endodontist.  The endodontist will be able to accurately assess the depth of the crack with a specialized microscope; it’s vital that the crack be accurately assessed in order to ensure proper treatment.  “If a crack is detected early on, with minimal pain and no detected inflammation or infection in the pulp, then it’s recommended that the crack be treated by binding it closed with a crown,” says Dr. Dugas.

Getting to the root of the matter


Root canal treatment is often not required in the early stages, but if a crown isn’t placed, the crack will eventually progress to the pulp and maybe even into the roots, the latter of which would mean the loss of the tooth.

A root canal removes the inflamed or infected pulp from the roots of the tooth, in order to prevent or treat a dental infection.  After administering local anesthesia, a rubber dam is applied to the tooth, and the endodontist accesses the pulp through a small hole in the chewing surface.  The endodontist will then use a specialized microscope to examine the crack internally.

If the crack doesn’t extend below the gum line, the endodontist will perform a root canal.  This involves the use of small files and disinfectant rinses to clean all of the inflamed or infected pulp from within the root canals.  Afterward, a rubber-like filling is heated and moulded into the root canals to seal them against reinfection.  The patient will need to have a crown (cap) placed over the tooth soon after, binding the crack together so it can’t progress.  Also, since the crown covers all surfaces of the tooth down to the gum line, it can cover the crack completely, which prevents bacteria from entering.

While tiny cracks are common and usually don’t cause problems, regular dental checkups are important because they allow your dentist to diagnose and treat a problem in the early stage.  If you’re experiencing tooth pain, and you aren’t sure why, avoid chewing on that side of your mouth and book an appointment with your dentist.

When its time to say goodbye

If your endodontist notices that the crack extends below the gum line and into the roots, the tooth will need to be extracted.  “This is because a crown would be unable to cover the crack on the roots.  Enough bacteria would eventually get through, causing the tooth to (re)abscess,” says Dr. Dugas.  “In other words, root canal treatment on a tooth with a cracked root is hopeless, and, therefore, extraction and replacement with a dental implant is recommended if there’s a root fracture.”

Written by Jane Doucet.  Reprinted with permission of the Ontario Dental Association and Magazine, 2015.

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