Written by Martin B. Goldstein, DMD Monday, 31 December 2001 19:00
No, it doesn't sound serious. It certainly won't kill you. But if it's you who has forsaken chewing on one side of your dentition because of persistent discomfort, you'll quickly recognize that the joy of eating has been compromised. Having experienced two such occurrences in a single year involving my own dentition, I became all too familiar with coronal fracture syndrome (CFS) and how it can progress. In my case, the end result was root canal, core, and crown on two first molars. Perhaps I delayed treatment too long. You know what they say about the shoemaker's "children"....
It may begin innocently when one day you begin to notice a lingering temperature sensitivity that you've never experienced before. First, cold is a problem. As time goes by and the issue remains unresolved, hot liquids or foods also become problematic. This is not good. You may also notice that if you attempt to eat something firm and impact the offender at just the right angle, a quick, sharp pain will ensue that tells you to chew elsewhere, quickly!
In some instances, these symptoms can be traced to a particular meal, when during chewing the primary fracture was caused by attempting to bite something unyielding, such as an olive pit or popcorn kernel. The pain is unmistakable. It generates a "hand to the cheek" gesture instantly. Chances are good that the temperature and chewing sensitivities described above will begin from this point on, and continue to worsen until the damaged tooth is addressed. Sensitivity to sweets may also arise.
But more often than not, the onset will be insidious. The discomfort simply begins to happen, seemingly out of the blue, prompting a call to one's dentist to investigate the cause. We've all received these inquiries. Many of us, myself included, in the course of a busy day are apt to wave off these limited exams and attribute symptoms to root sensitivity, due perhaps to gingival recession. The patient may be told to "monitor" progress and let the office know if the condition worsens. We may try root desensitization or send them on their merry way with a sample of Sensodyne toothpaste (Block Drug). After all, we looked, tapped, and saw nothing, and as is most often the case with fractures, the periapical film taken was unremarkable.
|Figure 1. A loss of cuspid protection.|
Owing to my personal experiences with CFS, my level of suspicion has been elevated. I now subscribe to the concept that many of my contemporaries are old enough to have lost what once was a cuspid-protected occlusion (Figure 1). What used to be happy molars and bicuspids languishing in the protection of fully cusped canines have taken on the role of whipping posts as we gnaw away at our sustenance. Cuspid guidance is frequently compromised as the cuspid loses its edge after years of wear and tear. Group function, "commonly found" in "commonly bruxing" boomers, now subjects our already amalgam-weakened posteriors to a barrage of lateral forces. The result? A multitude of cracked posterior teeth, some obvious and others not so obvious.
One other factor has strongly influenced my belief that we often fail to diagnose coronal fractures. Heavy involvement with a chairside digital camera has allowed me to photograph, with great clarity, a plethora of coronal fractures not easily visible to the naked eye. What used to be suspicions are now convictions. Having imaged a variety of such defects, both when anticipating them and when not even seeking them out, I now expect to see fractures whenever I am removing amalgam from dentitions like those described above. While not all such lesions are symptomatic, I would contend that many more exist than we are aware of, and as practitioners it is our responsibility to be suspicious of their existence when patients present with the symptoms similar to those described above.
The remainder of this article will offer a protocol for diagnosis and treatment of coronal fractures that I've developed over time when faced with deciding how to treat this common dental pathosis.
We're all aware of the typical methods of diagnosis. Certainly, if a fracture is suspected, an aid such as the Tooth Sleuth or similar product will allow us to isolate cusps to see if pain can be elicited by stressing a possible offending cusp. It's not uncommon to have the pain occur upon release of the bite hold. If reproducible, a positive response is most often a sure indication that a fracture exists. Take heed! There are fractures that may exist without offering a positive bite test.
Endo-Ice (Hygienic) or an ice chard are convenient ways to apply cold to a series of adjacent teeth in an effort to locate the problem tooth. A lingering response is more apt to be significant"”one in excess of 5 seconds that lingers well beyond removal of the stimulus. A 10-second response is almost a sure shot that the tooth is in trouble. Three seconds or less might be considered a normal response so long as the pain quickly subsides upon removal of the stimulus. I'm less apt to apply heat when diagnosing a coronal fracture, as opposed to those times where the diagnosis is directed at an ailing pulp.
|Figure 2. A deep fracture encroaches on the pulp space.|
Percussion sensitivity is not usually present when an early fracture is being investigated. This pleasure is reserved for fracture situations in which the pulpal tissue has already succumbed to the effects of the fracture and has undergone irreversible change. Thus, positive percussion and heat tests are more apt to occur with "mature fractures," those that have encroached on the pulp space directly and brought about classic symptomatology (Figure 2).
While it is of the utmost importance to put an integrated clinical picture together based upon testing and patient reports, I've included in my diagnostic scheme what is perhaps the most direct approach to determining if a fracture is behind the dental problem posed, ie, the diagnostic restoration removal (DRR).
The DRR is no more than removing an existing filling and affected tooth structure in order to visualize the floor of the cavity as well as the dentin integrity at the base of the individual cusps. This procedure is presented to the patient as a diagnostic procedure that might result in the placement of a permanent restoration at that same visit. It is further explained, however, that if the damage discovered (if any) dictates another course of treatment such as a crown and/or root canal, then the filling chosen to replace what was removed would serve only as an interim restoration.
|Figure 3. A vertical fracture noted on routine exam.||Figure 4. A sizable fracture revealed upon removal of amalgam.|
I am most apt to perform this test when hairline cracks are visible externally, or if the disposition of the restoration as well as the worn-in occlusal patterns are suggestive of a fracture. Sizable class II restorations with extensive wear are typical candidates for closer inspection, particularly if cuspid rise has been lost (as is commonly found with bruxers). The vertical marginal ridge fracture on the intact side of a two-surface amalgam (typically in maxillary bicuspids and mandibular molars) is a common sight (Figures 3 and 4). Please understand that I refer to fractures that appear to penetrate beyond what is visible, not the commonly found enamel craze lines that are ubiquitous.
Prior to any DRR, a clear picture of what the patient has been experiencing is noted. As would be expected, asymptomatic fractures are less apt to dictate endodontics. Conversely, teeth exhibiting fractures, either internally or externally, that are characterized by long- standing, consistent, and lingering temperature sensitivity, are prime candidates for root canal treatment before placing a definitive restoration.
|Figure 5. This vertical fracture resulted in a necrotic tooth.|
To cover all bases, it is prudent to vitality test asymptomatic fractures that are to be scheduled for DRRs. Fractures found to extend from the marginal ridge into the floor of the cavity prep towards the pulp zone may result in quiet necrosis. Such teeth are also asymptomatic, offering a false sense of security, as the patient hasn't noted previous discomfort. The fractured tooth proving to be nonvital is in most instances an endodontic candidate (Figure 5). Vitality testing should be performed either at the time of fracture detection (hygiene visit) or just prior to restoration removal, before anesthetizing the tooth. Failing to do so may leave you in the dark if a deep fracture is discovered that has the potential for pulpal involvement.
The DRR is punctuated by a digital close-up of the exposed cavity floor. It is hoped that if a fracture is present, it can be visualized, imaged, and presented to the patient as proof positive of what was responsible for their pain. Providing such evidence will render most patients very accepting of your treatment recommendations. An older method of detection involves the use of methylene blue incorporated into IRM, and left for a few days to allow the fracture to become stained. The magnification inherent to digital imagery, however, has allowed me to circumvent this technique.
|Figure 6. A marked distal lingual cusp fracture.||Figure 7. Amalgam removal reveals a large buccal cusp fracture.|
|Figure 8. Amalgam removal reveals a troublesome mesial-lingual cusp fracture.||Figure 9. A distal vertical fracture framed in a mirror.|
|Figure 10. A deep vertical fracture found unexpectedly.||Figure 11. A common vertical fracture easily visible.|
The two types of fracture that I am most likely to encounter are the midline fracture (extending from the marginal ridge towards the pulp) and the cusp fracture (typically horizontal in nature, located at the base of a cusp). The prognosis of the latter is influenced by the angle of the fracture. Cusp fractures that form near 90o angles with the vertical axis of the tooth are less likely to threaten the pulp than are those that occur at more obtuse angles (Figures 6, 7, and 8). The cusp fracture often is characterized by an altered light refraction, causing the semi-mobile portion of tooth to bear a different shade than the body of the tooth. The change in shade is abrupt.
Midline fractures are often more obvious, characterized by a frank fracture line that may also be stained darker by the corrosive residue of the overlying amalgam or old caries. They are much easier to image than their cusp-involved counterparts (Figures 9, 10, and 11). At times, it is helpful to visualize the cavity floor after it has been moistened with water. The refractive quality of the water droplet can sometimes magnify the defect. In other instances a dry field is better. I typically image the fracture under both conditions, and display the image that provides the better view. Take note: to visualize a cusp fracture it is sometimes necessary to clear the field of discolored dentin, as well as remove overhanging ledges of tooth structure that might obscure the view. To be sure, "clearing the field" does not infer wanton tooth removal. Such visualization removal is performed conservatively and in most cases results in fresh dentin fields that provide superior bonding surfaces. Finally, bringing one's imaged fracture site to a computer display and subsequently enlarging the image (digitally, via software) provides a near microscopic look at the area in question.
|Figure 12. Treatment rationale chart.|
While not gospel, I've included a chart with a skeletonized approach to treatment options for repairing teeth that have sustained fractures (Figure 12). It can be viewed as a framework for making a treatment decision. I hasten to remark that this approach is based solely upon my own experiences in treating patients for nearly 23 years, and is not research based. Nor can I swear to adhere to it 100% of the time. We'll all acknowledge that much of what we do is based upon results of past experiences. This is certainly true regarding dental treatment. We tend to repeat what we have found to work over time. What's more, gut feelings can be as significant as rigid protocol. Such intuition is experience based. Thus, while the less-experienced dentist might use this chart with greater conviction, those having already reached a comfort zone with regard to fracture treatment can simply compare notes.
Over time it becomes apparent that a small percentage of those teeth that should have responded positively to our nonendodontic solutions do crash and require root canal treatment, after the fact. I'm afraid there is no getting around this. What can be helpful is the practice of using a retrievable restoration that can be temporarily cemented if there is a suspicion that this might occur. I will often use a ceramo-metal restoration such as a PFM or Captek crown (Trident Dental) cemented with a softened mix of Temp Bond (Kerr), for anywhere from 6 to 12 months before final cementation in those cases that suggest endodontics might be necessary. Alternatively, there are those practitioners who elect to perform endodontics on any tooth that has sustained a fracture prior to placing an onlay or crown. While this approach can have certain advantages, there is little doubt that many more teeth will receive root canal therapy than really need to.
|Figure 13. A symptomatic molar prior to tooth preparation.||Figure 14. The mesial-lingual cusp was the culprit. This is same tooth seen in Figure 8.|
|Figure 15. The finished Empress 2 restoration.|
When the case is clearly an endodontic candidate and has been treated as such, I prefer the use of all-ceramic, bonded restorations as shown in Figures 13, 14, and 15. They illustrate a relatively conservative prep for an Empress crown. I enjoy leaving behind as much sound tooth structure as possible and, at the same time, maintaining nature's emergence profile. Tissue is very grateful for this. The tendency for such restorations to seamlessly blend into the remaining tooth structure leaves me with a good feeling.
I make no claim to having "discovered" what has just been presented. It was my intention to share my protocol for treating CFS, and at the same time suggest that digital imaging can be an important adjunct to the diagnostic process. Simply put, seeing is believing.
Having personally experienced CFS twice in a year has educated me about the risk of leaving such dental injuries unattended. I may have avoided the root canals and crowns had I acted sooner. Maybe not. Nonetheless, the dental practitioner should cozy up to a predictable protocol (of his own choosing) for treating CFS"” such that diagnosis and treatment are less of an adventure and more of a logical, predictable pathway.
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