Figure 1-37 After obturation, obturating material may extrude through accessory canals. However, sometimes an extensive "cement trail" of material up the side of the root extrudes through a fracture space, with no demarcation of accessory canals. This is suggestive of a vertical root fracture.
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Figure 1-38 Often the radiographic presentation of a vertical root fracture is the pattern of bone loss occurring in a "J-shaped" radiolucency, with the bone loss originating apically and progressing coronally up one side of the root.
The perception of pain in one part of the body that is distant from the actual source of the pain is known as referred pain. Whereas pain of nonodontogenic origin can refer pain to the teeth, teeth may also refer pain to other teeth as well as to other anatomic areas of the head and neck (see Chapter 3). This may create a diagnostic challenge, in that the patient may insist that the pain is from a certain tooth or even from an earache when, in fact, it is originating from a distant tooth with pulpal pathosis. Using electronic pulp testers, investigators found that patients could localize which tooth was being stimulated only 37.2% of the time and could narrow the location to three teeth only 79.5% of the time, illustrating that patients may have a difficult time discriminating the location of pulpal pain.27
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Figure 1-39 Extensive periodontal bone loss around an isolated tooth, with the adjacent teeth within normal limits, is suggestive of a vertical root fracture.
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Figure 1-40 When there is a disproportionate widening of a canal space compared with the canals in the same tooth or adjacent teeth, as seen in this mandibular second molar, a vertical root fracture should be suspected.
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Figure 1-41 A and B, A space between the obturation and the canal wall is highly suggestive of a split tooth.
Referred pain from a tooth is usually provoked by an intense stimulation of pulpal C-fibers, the slow conducting nerves that when stimulated cause an intense, slow, dull pain. Referred pain always radiates to the ipsilateral side of the tooth involved. Anterior teeth seldom refer pain to other teeth or to opposite arches, whereas posterior teeth may refer pain to the opposite arch or to the periauricular area but seldom to the anterior teeth.8,79 Mandibular posterior teeth tend to transmit referred pain to the periauricular area more often than maxillary posterior teeth. One study showed that when second molars were stimulated with an electric pulp tester, patients could discriminate accurately which arch the sensation was coming from only 85% of the time, compared with an accuracy level of 95% with first molars and 100% with anterior teeth.91 The authors also pointed out that when patients first feel the sensation of pain, they are more likely to accurately discriminate the origin of the pain. With higher levels of discomfort, patients have less ability to accurately determine the source of the pain. Therefore, in cases of diffuse or referred pain, the history of where the patient first felt the pain may be very significant.
Since referred pain can complicate a dental diagnosis, the clinician must be sure to make an accurate diagnosis to protect the patient from unnecessary dental or medical treatment.
CLINICAL CLASSIFICATION OF PULPAL AND PERIAPICAL DISEASES
Many attempts have been made over the years to develop classifications of pulpal and periapical disease. However, many studies have shown that there is not a great correlation between clinical signs and symptoms and what is actually present histologically. Since removal of the questionable tissues for histologic examination is not practical, clinical classifications have been developed in order to formulate treatment plan options. In the most general terms, the objective and subjective findings are used to classify the suspected pathosis, with the assigned designations merely representing the presence of healthy or nonhealthy tissue. These resulting classifications are used in determining whether to provide endodontic treatment.
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Figure 1-42 When a narrow, isolated periodontal defect is present, with the adjacent periodontal structures within normal limits, there is typically an associated boney dehiscence with an underlying vertical root fracture beneath (A and B). This mandibular second molar showed this type of defect, as observed upon surgical exploration (C-E).
Teeth with normal pulp do not exhibit any spontaneous symptoms. The pulp will respond to pulp tests, and the symptoms produced from such tests are mild, do not cause the patient distress, and result in transient sensation reversing in seconds. Radiographically, there may be varying degrees of pulpal calcification but no evidence of resorption, caries, or mechanical pulp exposure. No endodontic treatment is indicated for these teeth.
When the pulp within the tooth is irritated so that the stimulation is uncomfortable to the patient but reverses quickly after irritation, it is said to have a reversible pulpitis. Causative factors include caries, exposed dentin, recent dental treatment, and defective restorations. Conservative removal of the irritant will resolve the symptoms. However, sometimes this is easier said than done. Exposed dentin that has no other form of dental pathosis can sometimes have a sharp, quickly reversible pain when subjected to thermal, evaporative, tactile, mechanical, osmotic or chemical stimuli. This is known as dentin (or dentinal) hypersensitivity. Areas of cervically exposed dentin account for much of the observed dentin hypersensitivity.67
As will be described in later chapters, the fluid movement within dentinal tubules stimulates the odontoblasts and its associated fast-conducting A-delta nerve fibers, which in turn produce dental pain (Fig. 1-43). The more open these tubules are (for example, from a newly exposed preparation, dentin decalcification, dental scaling, tooth bleaching materials, or fractures), the more the tubule fluid will move and, subsequently, the more the tooth is predisposed to dentin hypersensitivity. When making a diagnosis of pulpal pathosis, it is important to discriminate this sensation from that of a reversible pulpitis, which would be secondary to caries, trauma, or new or defective restorations. Detailed questioning of recent dental treatment, not to mention a thorough clinical and radiographic examination, will help to separate dentin hypersensitivity from other dental pathosis, as the treatment modalities for each are completely different.12
Figure 1-43 Dentinal tubules are filled with fluid that, when stimulated, will cause sensation. Temperature changes, air, and osmotic changes can provoke the odontoblastic process to induce the stimulation of underlying A-delta fibers.
As the disease state of the pulp progresses into an irreversible pulpitis, treatment will be necessary. This classification may be divided into symptomatic or asymptomatic irreversible pulpitis, with the degree of clinical symptoms escalating over time.
Symptomatic Irreversible Pulpitis
Teeth that are characterized as having symptomatic irreversible pulpitis exhibit intermittent or spontaneous pain, whereby rapid exposure to dramatic temperature changes (especially to cold stimuli) will elicit heightened and prolonged episodes of pain even after the source of the pain is removed. The pain may be sharp or dull, localized or referred. Typically there are minimal changes in the radiographic appearance of the periradicular bone. With advanced irreversible pulpitis a thickening of the periodontal ligament may be evident, and there may be some suggestion of pulpal irritation by virtue of extensive canal calcification. Deep restorations, caries, pulp exposure, or any other direct or indirect insult to the pulp, recently or historically, may be present and may be seen radiographically or clinically or be suggested from a complete dental history. Typically, when a symptomatic irreversible pulpitis remains untreated, the tooth will eventually succumb to necrosis.
Asymptomatic Irreversible Pulpitis
Occasionally, deep caries will not produce any symptoms, even though clinically or radiographically the caries may be well into the pulp. Left untreated, the tooth may become symptomatic or even necrotic. In cases of asymptomatic irreversible pulpitis, endodontic treatment should be performed as soon as possible so that this conversion does not take place and cause the patient distress.
When pulpal necrosis (or nonvital pulp) occurs, the pulpal blood supply is nonexistent and the pulpal nerves are nonfunctional. It is the only clinical classification that directly attempts to describe the histologic status of the pulp (or lack thereof). This condition is subsequent to symptomatic or asymptomatic irreversible pulpitis. Under complete necrosis and before any pathosis extends into the periodontium, the tooth is typically asymptomatic. It will not respond to electric pulp tests or to cold stimulation. However, if heat is applied for too long, the tooth may respond, possibly relating to remnants of pulpal fluid or gases expanding and extending into the periapical region. As previously discussed, a traumatic injury to a tooth may prevent the lack of a response to pulp tests and mimic that of pulpal necrosis; therefore a good dental history is imperative. Pulpal necrosis may be partial or complete and it may not involve all of the canals in a multirooted tooth. For this reason, the tooth may present with confusing symptoms, whereby pulp testing over one root may give no response and pulp testing over another root may give a vital response, and the tooth may exhibit symptoms of an irreversible pulpitis.