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Endodontics Supporting Your Practice

How does one decide whether a crack/craze line on an asymptomatic tooth should be attempted to be removed, either with a restoration or a crown?


Mary DThis question was submitted by a general dentist: How does one decide whether a crack/craze line on an asymptomatic tooth should be attempted to be removed, either with a restoration or a crown?

Dr. Mary Dabuleanu of Dabuleanu Dental, in collaboration with Dr. Suham Alexander, Oasis Clinical Editor, provided the following quick initial response







Fig 1a

Fig 1a: Craze Line

A craze line is a crack that involves only enamel and is usually asymptomatic. Most teeth have craze lines.  Unless the crack is of aesthetic concern, no treatment is necessary, Fig 1a.






Fig 1b

Fig 1b: Vertical Crack Extending Apically

A true crack usually involves the enamel, dentin and eventually the pulp.  These cracks begin occlusally and travel sub-gingivally.  The crack may occur mesio-distally or bucco-linugally, Fig 1b.  As the crack extends apically, the pulp becomes involved due to the more central location of these cracks.









Patients with “cracked tooth syndrome” usually describe pain with chewing a certain way or may experience pain to cold on the affected tooth.  The severity of symptoms depends on the degree of pulpal inflammation and subsequent treatment depends on the pulpal diagnosis and on the extent of the crack. 


Krell et al (2007) studied the clinical outcomes of cracked teeth diagnosed with reversible pulpitis. They found that 20% of teeth with cracks, diagnosed as reversibly inflamed and receive a crown, will require root canal treatment within 6 months.

Treatment also depends on the extent of the crack and whether the surrounding periodontium has been affected (i.e. probing greater than 3 mm). 

A crack with an associated periodontal pocket usually has a poor prognosis and extraction is advisable.

Teeth with cracks, even those that extend vertically to the CEJ, may be considered for root canal treatment and a crown if there is no deep periodontal probing surrounding the location of the crack.  Also, the patient must be fully prepared that all cracked teeth have a questionable long term prognosis as cracks may continue to propagate despite our best efforts to retain these teeth.

When root canal treatment is performed on these teeth, placing an orthodontic band helps to prevent further crack propagation in the interim before a final crown is placed.

Tan et al (2006) assessed the survival rate of root filled cracked teeth over a 2 year period.  All teeth received a crown or an orthodontic band.  The two year survival rate of these teeth was 85.5%.  Pre-existing periodontal pockets, the presence of multiple cracks and terminal teeth in the dental arch significantly affected tooth survival.

Moreover, Kim et al (2013) have outlined a treatment protocol commonly used for cracked teeth depending on the stage of pulpal pathology present.  A treatment algorithm is shown in Figure 2.

In summary, cracks present both a diagnostic and treatment dilemma. The decision to treat and restore these teeth involves a careful discussion with the patient of the prognosis time and cost.  When treated, a good number of cracked teeth can remain functional for a considerable time.

Cracked tooth algorithm

Figure 2: Treatment Algorithm for Cracked Teeth



  1. Kim Sin-Young, Kim Su-Hyun, Cho Soo-Bin, Lee Gyung-Ok, Yang Sung-Eun.  Different Treatment Protocols for Different Pulpal and Periapical Diagnoses of 72 Cracked Teeth. JOE Volume 39 No 4, April 2013: 449-452
  2. Krell Keith, Rivera EM.  A Six-Year Evaluation of Cracked Teeth Diagnosed with Reversible Pulpitis: Treatment and Prognsosis. JOE 2007; 33:1405-1407
  3. Cracking the Cracked Tooth Code: Detection and Treatment of Various Longitudinal Fractures. Endodontics: Colleagues of Excellence Summer 2008: 1-8.


Dr. Mary Dabuleanu

Mary Dabuleanu obtained her Doctorate of Dental Surgery from the University of Toronto in 2002. She continued her training in Montreal, Quebec, where she completed a full year general practice residency program through McGill University at the Royal Victoria Hospital. 

Following a few years in general practice, Dr. Mary Dabuleanu received her Master of Science degree and certificate in Endodontics from The University of Detroit Mercy Detroit, Michigan in 2007. Dr. Mary Dabuleanu is a Fellow of the Royal College of Dentists of Canada FRCD(C). 


Do you have any particular question on this topic? Do you have any comments or suggestions? Email us at oasisdiscussions@cda-adc.ca

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  1. David Tessier June 10, 2014

    Very good article. What is the theory behind the statement “cracks may contniue to propagate despite our best efforts”?I am assuming these teeth are crowned and vital? In my experiece, it is nonvital teeth, crowned that can fracture/split. My other experience in the last 10-15 years is a dramatic number of cracked teeth and worn teeth seen. As a society we are taking out our stresses in life on our teeth. I am a firm believer in bruxism appliances, always screening grinding/clenching in all new patients.

  2. Brent Hehn June 12, 2014

    Good review and very important subject. What about teeth with cracks with no symptoms and no sign of decay? Cracks need a force to be created in the first place, treating the occlusal disease by careful equilibration or simply by wearing a night guard at night may help prevent further crack propagation in totally symptomatic patients. What about onlays, either in composite or porcelain? I have lots of patients that have cracks that are totally asymptomatic but have occlusal interferences, when we restore these teeth we cannot always predict the outcome. Crowns are very aggressive and we don’t have to always take away so much tooth to create a restoration that prevents or mitigates further crack propagation. IMHO.

  3. Brian Spackman June 24, 2014

    For “asymptomatic” cracks, the cause of the crack may be traumatic occlusion or may be a single traumatic event (e.g. biting on a popcorn kernel). A Tooth-Slooth or Frac-Finder will usually tell you quickly if the crack goes into the dentin or possibly beyond. Also, air applied to the cracked tooth can trigger localized pain that lingers or dissipates quickly. If it lingers, the pulp prognosis is less-favorable but not necessarily irreversible. If any symptoms of pain can be elicited either by air, cold-test, or cuspal deflection with the Tooth-Slooth, a conservative treatment that can be done is a composite filling that wraps and/or caps the involved cusp(s) followed by observation for further symptoms. The cavity prep design must include significant grooves, bevels,and/or undercuts that “grab” onto the cusp for mechanical retention of the cusp by the filling. In many cases, I have seen complete resolution and ongoing vitality in teeth I thought initially I was going to have to treat endodontically and crown. I think many teeth can be saved without crowning if the operator designs the composite restoration to hold the cracked cusp in such a way that flexure is minimized. Relying on shear bond strength is not sufficient. In younger patients, I think going to a crown should only be done if there is no reasonable alternative.

  4. Dr. Krystle Fenton July 23, 2016

    Great information and very useful discussion. Most of my patients could definitely make use of this article when explaining the need to undergo further screening for such cases. In my clinic, I use DIAGNOdent as a way to further verify if there are softening of the enamel on the surfaces of my patients’ teeth. Cracked tooth syndrome could be very difficult to treat but with our experience, we are able to help many patients as well.


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