Wright & Beatty
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How to prevent root canals through the diagnosis and treatment of coronal fractures

As a general dentist for more than 14 years, I’ve come across my share of cracked teeth. In my first ten or so years of dental practice, I would see a fracture line through a marginal ridge and either “watch it” or place an interproximal MO or DO to cover it up. Maybe I would recommend a nightguard if the patient had a lot of cracked teeth. If I noticed that the fracture seemed to be getting deeper over the years or was causing the patient’s tooth to hurt, I would recommend a crown. It seemed like over treatment to recommend a full cuspal coverage crown or onlay because of a small fracture line that the patient wasn’t even aware of.

Fast forward to the present. My philosophy towards treating fractured teeth has completely changed from observation to prevention. The number one reason that we are not able to help a patient save their tooth is when a previously undetected fracture has extended on to the root surface. It’s really terrible to be the one to tell someone that you can’t help them when they have no other option that to have their teeth taken out. Dr. Beatty and I have learned how to recognize, diagnose, treat and most importantly help patients prevent fractured teeth from occurring. We would love to share this information with you and your patients. Enjoy!

Classifications of fractured teeth:
1. Fractured cusp – undermine one or more cusps, usually do not expose the pulp
2. Coronal fracture – Begin over marginal ridges. Extend into pulp and on to root surface over time.
3. Vertical root fracture – Begin on root surface. Usually after RCT is completed. More common in cases of excessive pressure being applied to the roots or overcontouring canals

We will focus on the coronal fracture in this post.

How to recognize and diagnose:

The best way to recognize a fracture is with a transilluminating light. I have seen dentists use the fiber optic light on a high-speed handpiece, the wand shaped Transilluminator that we use in our office (see photo below) and even a green light to pick up the gradient of diffusion through the dentin. One of the most important properties of light is refraction, which states that as light travels through a medium, it will gradually decrease in intensity. If however the medium changes (such as when a crack in the tooth allows air or saliva in), the amount of light in the dentin will stop abruptly. The differential in intensity on either side of the crack is usually directly proportional with the depth of the fracture. I have included several photos below that show a fracture line under transillumination. There is a learning curve in the interpretation of fractures that comes from years of experience, but you will quickly start noticing fractures as soon as you start looking for them. Many of your current patients will benefit from onlays or crowns that you can place BEFORE they start developing tooth pain. Another benefit to looking for (and transilluminating) fractures on any patients with toothaches is that you will become a better diagnostician. (Don’t forget to probe where the fracture meeting the gingiva to see if it extends below the alveolus and look for vertical bone loss on a bitewing.) You will begin to understand how to “treat the patient” and not “treat the radiograph”. You will also find that you have fewer patients with toothaches after placing a new crown.

How to treat a fractured tooth:

Treatment plan is frequently dependent on the depth and location of the fracture as well as if the patient is having any symptoms. The following are guidelines:
1. Fractures through marginal ridges should have all adjacent cusps overlayed with a restoration to prevent continued flexure of the cusps. Refer to study below.
2. Fractures through the lingual and facial aspect of a crown rarely involve the pulp (that’s way you won’t see coronal fractures on radiographs).
3. When your patient complains of non lingering pain to cold, only has pain upon release when chewing and has no spontaneous pain, place cuspal coverage restoration and monitor for improved symptoms. If they develop lingering pain to cold or a dull spontaneous ache, begin RCT and determine the extent of the fracture through direct visualization along the chamber walls.
4. Always let your patients know during an exam if they have cracked teeth. Because habits are usually responsible for their presence, if they have one fractured tooth, they probably have many.

How to prevent teeth from fracturing:

Discuss the reasons that teeth fracture and why prevention is so important. We all want to help our patients maintain excellent oral hygiene and be free of toothaches and missing teeth. A recent study compared dental practices that were proactive about providing cuspal coverage to their patients with fractured marginal ridges. (Remember, this is before they had any symptoms) When compared to the proactive offices, 60% of the fractured teeth in the other practices patients needed root canals within 3 years of initial diagnosis and extractions within 5 years.

The take home message is:
1. Place onlays or crowns on teeth that already have marginal ridge fractures (if the patient doesn’t follow your recommendation, document it in the chart so when you do the RCT or take the tooth out in several years, they will listen to you from then on.
2. Fabricate hard, flat plane acrylic nightguards for clenchers.
3. Turn lights down and transilluminate during exams to make fractured teeth visible.
4. Incorporate fractured teeth into your differential diagnosis with searching for the cause of a tooth ache on a tooth with a shallow or no filling.
3. Counsel patients on the long term effects of chewing hard candies, corn nuts, ice, lingual barbels. (Does anyone really want more root canals and exos?)

September 2019
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