There is an epidemic out there and those of us who have been in practice for more than a few years have seen it - Cracked Tooth Syndrome (CTS). In my endodontic specialty practice it is not uncommon for me to see several patients a day that have been referred for treatment of a CTS related problem. In some cases Endodontic treatment is required, while in other cases it is not. The key in managing these patients (ie/ not performing endodontics on every case) is understanding the symptoms, mapping the fracture and then deciding if pulpal symptoms or the prospective restoration require that endodontics be performed. Many of the teeth with CTS can be treated with conservative restorative procedures that remove and restore the fractured portion of the tooth without the need for endodontics. Other teeth will require elective endodontics simply because removal of the cracked portion of the tooth (and/or old restoration) leaves so little tooth that placement of a cusp protected restoration is not possible without the assistance of a post retained core. The decision to perform Endodontic treatment in those cases is made strictly for prosthetic reasons rather than for pulpally related problems.
Experienced clinicians (who perform a lot of C & B in their practices) appreciate the benefits of Endodontic treatment of teeth with CTS symptoms. It prevents unpredicted loss of cusps or core material during crown preparation, lessens the chance of post operative thermal and biting sensitivity as well as ensuring that the newly cemented casting will not have to be accessed for endodontics in the future.
Signs and Symptoms
CTS symptoms can make the case relatively easy to diagnose because once the weak area is discovered symptoms can be reproduced consistently. However, when the symptoms are difficult to reproduce in the chair, CTS can occasionally be difficult to diagnose. Thermal complaints (mostly to cold) are common. Patients will often complain that the tooth produces a sharp, momentary, electric-type sensation when the tooth is chewed upon. The most important symptom is pathognomonic for CTS - Pain upon release of occlusal pressure. Patients may have to hit the tooth "just the right" for the symptom to be reproduced, which is why the sensitivity is sometimes described as intermittent or difficult for the patient to reproduce on their own. Symptoms occur as a direct result of the closing rather than the opening of the fracture. (Remember the implications of Brannstrom's Hydrodynamic theory of pulpal/dentinal innervation.) The rapid "backflow" of fluid in the dentinal tubule (that occurs as the crack closes) is responsible for the sharp symptom. Hard, small, seed-like or chewy foods seem to trigger the symptom best, though sometimes not consistently. Patients will complain about their inability to use one side of the mouth for fear that they will cause this sharp sensation. It also can result in a residual dull ache that lingers for a short time after initiation of the initial sharp response. Fortunately, the CTS tooth can be diagnosed with very simple tools and symptoms can be localized with patience and proper diagnostic technique. Tests focus on identifying the specific portion of the tooth that is fractured.
Step 1- Identify the Tooth in Question
One of the best tests to confirm CTS symptoms is the cotton roll test. Merely place standard dry cotton roll over the occlusal surface of a single tooth and ask the patient to close and clench firmly. Then ask them to release pressure quickly. Watch carefully as they release pressure on the tooth. Very often the patient will react sharply and a hand may come up to their mouth. The response is reproducible, consistent and sharp. The cotton roll test is particularly good for teeth with complete or incomplete M-D cracks. Once the initial cotton roll test is positive, we know that there is a fracture in the tooth. We now have to establish the extent of the fracture in order to determine which treatment is indicated.
Step 2- Examine the tooth with magnification
Once the tooth has been discovered we shift our attention to finding out which part(s) of the tooth are involved. Magnification is essential at this stage with high-powered Loupes (as a minimum). You cannot identify what you cannot see! The SOM (The surgical operating microscope) is the best tool to examine for this problem. Look closely for Mesial and Distal marginal ridge fractures and craze lines. These often continue under occlusal restorations and emerge in the opposite marginal ridge (M-D crack). Discolored or stained cracks are a good indicator of long term fractures that may have been exacerbated by a recent occlusal trauma. (Popcorn, hard candy and very chewy food can result in focused occlusal pressures that propagate the original fracture and increase the symptoms.) Bucco-lingual fractures are much more rare but they can occur as well.
Step 3 Transillumination
A very simple way to determine where the fracture is located is to use a Transilluminator (small localized wand-type light source). Although a dedicated light source is the most efficient, the light from a Fibreoptic handpiece, intraoral camera or curing light, placed on the buccal and then lingual surface of the tooth can often give us a clue as to the extent of the fracture. (Make sure to turn off the overhead dental light when you do this, in order to maximize the contrast.) As with a prism, a normal tooth will transfer light through the continuous layers of enamel and dentin to the other side of the tooth. Any crack of significant depth will interrupt the flow of light through the enamel/dentin complex and result in the side closest to the light source to be lit up, while light is not transferred across the fracture. The opposite side or involved cusp remains darker.
Step 4- Localization
We now have identified the suspect portion of the tooth. We now must determine if merely a cusp is involved or whether the fracture involves multiple cusps. Should we suspect a cusp fracture, the best tool for diagnosis is the Tooth Slooth. The White version has a small indentation in one end that is placed over each individual cusp to determine which of them is weak. Mandibular 2nd molars are notorious for developing distal marginal ridge fractures that propagate mesially. Large MOD amalgams in this tooth can also leave the lingual cusps relatively unsupported. DL and ML cusp fractures are very common. Maxillary premolars have similar characteristics when heavily restored. Such teeth will react both to a cotton roll and a Tooth Slooth, when it is applied to the weak cusp. We have now determined the location of the weak area.
Step 5 Deciding Whether Endodontic Treatment is Necessary
If the patient's current complaint is limited to sensitivity to pressure with NO thermal sensitivity, then the tooth likely has a cusp fracture(s) that does not involve the pulp. The original restoration should be removed entirely. The tooth is closely examined for evidence of fracture lines and once detected, the weak cusp(s) is removed and shod with a cusp-replaced restoration. The patient should be reassessed in a few weeks to determine that the original complaint is gone. In many cases this is all that is required and further restorative or endodontic treatment is not indicated.
If the patient's current complaint is limited to sensitivity to pressure with cold sensitivity, then we can assume that there is some level of pulpal inflammation. Replacement of the weak area with a restoration could possibly result in elevated levels of thermal (cold) sensitivity that may not be tolerable for the patient. Therefore the patient should be warned that restoring the tooth might relieve the sensitivity to occlusion but that thermal symptoms may necessitate Endodontic treatment if symptoms are too severe. Lingering thermal sensitivity to cold is another indication that an irreversible situation has occurred and Endodontic treatment is necessary. Patients should always be told that such restorations are only an attempt to delay the inevitable...it is likely that this tooth will require a cusp protected casting in the future and they should not be surprised if Endodontic treatment is recommended in the future.
If the patient's current complaint is sensitivity to pressure AND thermal sensitivity to heat, then we can consider the pulp to have undergone irreversible changes caused by bacteria entering the pulp through the fracture. The tooth is in End Stage pulpitis and Endodontic treatment is mandatory. In an attempt to avoid endodontic treatment, some dentists may attempt to restore these teeth. These restored cases can rapidly become necrotic and asymptomatic and these are the patients who call you a few months later in extreme discomfort, frequently at night. The pulp is becoming non-vital, the most uncomfortable stage of pulpal disease. Emergency endodontic procedures must be initiated at this point but they must be performed with the understanding that accessing the tooth may reveal fractures along the pulpal floor. Such fractures represent the earliest stages of Split Tooth and represent a poor prognosis, even more so when a furca lesion is present.
Sometimes the dentist will remove the existing restoration, only to find that several cusps literally fall off the tooth as the cracked area is encountered. In the case of the typical MOD amalgam, loss of both buccal or lingual cusps frequently leaves so little intact tooth structure. In those cases, elective endodontics may be preferred over attempts to place large pin reinforced or bonded restorations. Serious consideration should be given to elective procedures before expensive castings are placed or the tooth is used as the critical abutment of a fixed prosthesis.
As with any tooth that is being considered for extensive restorative treatment, examination of the condition of the chamber and canals is mandatory. Teeth with evidence of heavy calcification should be considered pulpally compromised. We would lean TOWARD treating teeth like these with Endodontics NOW rather waiting for further calcification that makes the case more difficult to treat on the future.
Not every tooth with CTS symptoms requires Endodontic treatment. By using simple diagnostic tests the extent of the fractures and possible pulpal implications can be reliably determined. Occasionally, it is necessary to remove the weak portions of the tooth to make this final determination. Placement of diagnostic temporary restorations (removal of a weak cusp and replacement with a short term IRM) can frequently eliminate the need for Endodontic referral. By using proper diagnostic techniques you can be sure that the cases that you send to the Endodontist DO require endodontics and referral is warranted.
ROOTS Summit III June 18-22, 2003 in Anaheim California
$350 US registration fee for 4 full days of quality CE! Its at the Disneyland Hotel.
Bring your Family!Many World Class Endo speakers picking up where we left off last year!
Cliff Ruddle (Retreatment) John McSpadden ( Instrumentation), Martin Trope ( Obturation and Success), John West ( Creating "The Look"), Jim Roane ( Balanced Force Technique), Steve Senia (Lightspeed) John Stropko (The "No Cone" System S "Squirt" technique), Fred Barnett (Treatment Resistant AP), Arnaldo Castellucci (Working length and Endo Surgery), Barry Musikant ( The Safe Sider Instrument) Drs. Koch and Brave (RealWorld Endo) and much more. "Lunch and Learn" every day. Exhibits, Parties and dinners ! It's a non stop Endo University !Check out www.rxroots.com or call me for info. Don't miss it !