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Endodontics diagnosis

  • Clinically Normal Pulp
  • Chronic Reversible Pulpitis
  • Acute Reversible Pulpitis
  • Chronic Irreversible Pulpitis ✅
  • Acute Irreversible Pulpitis
  • Pulp Necrobiosis
  • Pulp Necrosis with Infection
  • Pulpless, Infected RCS

Tooth fracture Pathological tooth resorption Endodontic Abscesses/Cellulitis, Cysts, and Flare-ups

Clinically Normal Pulp

The term “clinically normal pulp” is used for a pulp that has no signs or symptoms to suggest that any form of disease is occurring. The term “clinically” is used since such a pulp may not be histologically normal and/or may have some mild inflammation, fibrosis (scarring) as a result of previous injury or stimuli such as caries, restorations, trauma, and so forth. However, for all intents and purposes, the tooth does not have any pulp pathosis that requires treatment. Typical symptoms—no symptoms. Clinical findings—normal reaction to cold and electric pulp sensibility tests as long as there has been no calcification of the coronal pulp space; will not respond to heat; percussion and palpation are normal. Radiographic findings—no radiographic signs of pathosis; normal periodontal ligament (PDL) space and lamina dura. Associated periradicular conditions—clinically normal periapical tissues. Key findings for diagnosis—no symptoms and no abnormal findings.

Pulpitis

Pulpitis can take several forms—it can be reversible or irreversible, and both of these stages of the disease process can

Chronic Reversible Pulpitis

Typical symptoms—the pain has been present for a long time (e.g., months); occasional sensitivity to heat, cold and/or biting; pain only occurs with extreme temperature changes (e.g., ice cream and cold drink from the fridge); pain is sharp but mild; pain is of short duration (e.g., a few seconds); tooth may have had a restoration prior to the onset of symptoms. Typical clinical findings—there may be caries, a restoration breaking down or a crack; thermal pulp sensibility tests can reproduce the pain associated with heat and/or cold stimuli; the pain with thermal testing will be sharp and of short duration; there may be pain on biting or tenderness to percussion on a specific cusp if a crack undermines the cusp; caries may be seen if extensive enough or the restoration may have signs of marginal breakdown. Radiographic findings—normal PDL space and lamina dura; occasionally may be condensing osteitis; rarely, a slightly widened PDL space. Associated periapical/periradicular conditions—usually clinically normal periapical tissues; occasionally may have primary acute apical periodontitis or occasionally condensing osteitis indicating chronic reversible pulpitis and chronic apical periodontitis for some time. Key findings for diagnosis—the nature of the pain (thermal sensitivity, sharp pain, short duration). Distinguish from acute reversible pulpitis by the length of time the problem has been present and the occasional nature of the symptoms. Distinguish from acute and chronic irreversible pulpitis by the short duration of the symptoms and the extreme temperature changes required to cause the pain.

Acute Reversible Pulpitis

Typical symptoms—the pain has only been present for a short time (e.g., a few hours or days); the pain is present every time the stimulus is applied to the tooth; there is sensitivity to heat, cold and/or biting; pain only occurs with extreme temperature changes (e.g., ice cream and cold drink from the fridge); pain is sharp but mild and of short duration (e.g., a few seconds); may have had a restoration prior to onset of symptoms. Clinical findings—may be caries, a restoration breaking down or a crack; thermal pulp sensibility tests can reproduce the pain associated with heat and/or cold stimuli; pain with thermal testing will be sharp, and of short duration; may be pain on biting or tenderness to percussion on a specific cusp if a crack undermines the cusp; caries may be seen if extensive enough or restoration may have signs of marginal breakdown. Radiographic findings—normal PDL space and lamina dura; occasionally may have condensing osteitis; rarely, a slightly widened PDL space may be evident. Associated periapical/periradicular conditions—usually clinically normal periapical tissues; occasionally may have primary acute apical periodontitis; occasionally condensing osteitis indicating chronic reversible pulpitis and apical periodontitis for some time before acute presentation. Key findings for diagnosis—the nature of the pain (thermal sensitivity, sharp pain, short duration). Distinguish from chronic reversible pulpitis by the length of time the problem has been present and the regular nature of the symptoms. Distinguish from acute irreversible pulpitis by the short duration of the symptoms and the extreme temperature changes required to cause pain.

Chronic Irreversible Pulpitis

Typical symptoms—the pain has been present for a long time (e.g., months); occasionally pain to heat, cold and/or biting; pain occurs with minor temperature changes (e.g., tap water); pain is sharp and severe, then becomes a dull ache; pain lingers (e.g., more than five minutes); may have had a restoration prior to onset of symptoms. Clinical findings—may be caries, a restoration breaking down or a crack; thermal pulp sensibility tests can reproduce the pain associated with heat and/or cold stimuli; pain with thermal testing will be sharp, painful and lingers; may be pain on biting or tenderness to percussion on a specific cusp if a crack undermines the cusp. Radiographic findings—caries may be seen if extensive enough; normal PDL space and lamina dura; occasionally condensing osteitis; a slightly widened PDL space may be evident. Associated periapical/periradicular conditions—usually clinically normal periapical tissues; occasionally may have primary acute apical periodontitis; occasionally condensing osteitis indicating chronic reversible or irreversible pulpitis and apical periodontitis for some time. Key findings for diagnosis—the nature of the pain (thermal sensitivity, sharp pain, then a dull ache that lingers). Distinguish from acute irreversible pulpitis by the long time that the pain has been present and the occasional nature of the symptoms. Distinguish from acute reversible pulpitis and chronic reversible pulpitis by the lingering pain, and only minor temperature changes required to cause the pain.

Acute Irreversible Pulpitis

Typical symptoms—the pain has only been present for a short time (e.g., a few days or less); pain to heat, cold and/or biting; pain occurs with minor temperature changes (e.g., tap water); pain is sharp and severe, then becomes a dull ache; pain lingers (e.g., more than five minutes); pain may be spontaneous; pain may occur when lying down; pain may wake the patient at night; may have had a recent restoration. Clinical findings—may be caries, a restoration breaking down or a crack; thermal pulp sensibility tests can reproduce the pain associated with heat and/or cold stimuli; pain with thermal testing will be sharp, very painful and lingers; may be pain on biting or tenderness to percussion on a specific cusp if a crack undermines the cusp. Radiographic findings—caries may be seen if extensive enough; normal PDL space and lamina dura; occasionally condensing osteitis; a slightly widened PDL space may be evident. Associated periapical/periradicular conditions—often have primary acute apical periodontitis; occasionally condensing osteitis indicating chronic apical periodontitis for some time prior to the acute presentation; sometimes clinically normal periapical tissues (e.g., if no tenderness to percussion). Key findings for diagnosis—the nature of the pain (thermal sensitivity, sharp and severe pain, then a dull ache that lingers). Spontaneous pain, waking at night, and worse lying down are positive signs of acute irreversible pulpitis. Distinguish from chronic irreversible pulpitis by the short time that the pain has been present and the regular nature of the symptoms. Distinguish from acute and chronic reversible pulpitis by the severity and lingering pain, and only minor temperature changes required to cause pain.

Pulp Necrobiosis

A tooth with necrobiosis has both inflamed (acute irreversible pulpitis) and necrotic (usually infected) pulp tissue.21 Many dentists use “partial necrosis” for this stage of the disease process. However, Grossman21 suggested the term “necrobiosis” because it more accurately indicates the condition with “necro-” indicating necrosis and “-bio-” indicating live tissue. The necrotic tissue may be in the pulp chamber with the inflamed tissue in the root canal(s), or the different conditions may exist in different canals of a multicanal tooth. Teeth with this condition are difficult to diagnose since they often present with a mixture of the symptoms and signs of both pulpitis and necrosis with infection.11 Typically, this stage of the disease process is only present for a short time— perhaps a few hours only or up to a few days. Typical symptoms—the pain has only been present for a short time (e.g., a few days or less); typically history of very recent pain heat, cold and/or biting; if temperature changes cause pain then usually only minor temperature changes required (e.g., tap water); pain may be sharp and severe, then may become a dull ache; pain lingers for a long time; pain may be spontaneous; patient typically reports a mixture of symptoms suggesting pulpitis or an infected root canal system; pain can be quite distressing for the patient; may have had a recent restoration. Clinical findings—may be caries, a restoration breaking down or a crack; pulp sensibility test results are mixed and frequently inconclusive or inconsistent with the patient’s description of symptoms; often tenderness to percussion; may be pain on biting. Pain may be severe and may be relieved by “swishing” iced water around the tooth; relief lasts for seconds to a minute and may require constant application of cold water; a “bead” of pus may emerge when the pulp chamber is opened and this relieves the pain. Radiographic findings—caries may be seen if extensive enough; usually have normal PDL space and lamina dura; sometimes a slightly widened PDL space may be evident. Associated periapical/periradicular conditions—usually clinically normal periapical tissues (e.g., if no tenderness to percussion); sometimes have primary acute apical periodontitis (e.g., if tender to percussion). Key findings for diagnosis—the patient’s symptoms are often mixed (i.e., symptoms of pulpitis and an infected root canal system at the same time). The pulp sensibility tests usually do not correlate with the patient’s symptoms, and the pain is often severe and distressing.

Distinguish from acute irreversible pulpitis by the mixed symptoms and inconsistency between symptoms and pulp sensibility tests. Distinguish from acute and chronic reversible pulpitis by the nature of the pain and its severity, plus the pulp sensibility tests results. Distinguish from necrotic and infected pulp by the nature of the pain and inconsistent symptoms. Distinguish from a pulpless and infected root canal system as there is no periapical radiolucency.

Pulp Necrosis with No Signs of Infection

The dental pulp may undergo necrosis for several reasons. The most common reason is due to the bacterial invasion through caries, cracks or restoration breakdown that will ultimately lead to the pulp necrosing and becoming infected. However, some pulps may necrose as a result of trauma when the tooth is luxated or displaced sufficiently to sever the apical blood vessels. If the pulp cannot revascularize, then it necroses but does not necessarily become infected unless there is a coronal pathway of entry for bacteria. In cases of necrosis without infection, there will be no periapical tissue response6–10; that is, there will be no apical periodontitis (Figure 8-3). The term used for this condition includes “no sign of necrosis” because it is not possible to categorically state that the tooth is “not infected,” based on the information obtained from a clinical and radiographic examination. It is known that radiographic signs of apical periodontitis (i.e., a radiolucency) take at least several months to be visible once a pulp becomes infected,1 hence, the lack of a radiolucency does not necessarily indicate the lack of an infection. It merely means there was no sign of apical periodontitis (and hence no sign of root canal infection) at the time the radiograph was exposed. Typical symptoms—no pulp-related symptoms (i.e., no thermal sensitivity); may have a history of trauma to the tooth. Clinical findings—the tooth does not respond to pulp sensibility tests; may be some tooth discolouration; tooth may have a crack or fracture (e.g., if history of trauma), caries or a restoration. Radiographic findings—no abnormal observations of the tooth unless trauma has caused a fracture; normal PDL space and lamina dura. Associated periapical/periradicular conditions—clinically normal periapical tissues. Key findings for diagnosis—no symptoms, no response to pulp sensibility tests but no other abnormal findings. Distinguish from pulp necrobiosis as there are no symptoms and no signs of apical periodontitis. Distinguish from a necrotic and infected pulp as there are no signs of apical periodontitis.

Necrotic and Infected Pulp

When a pulp necroses as a result of bacterial invasion of the tooth, it will become infected over time. The bacteria will remove the necrotic tissue quite rapidly (within one to two months, depending on whether or not the pulp is exposed to the mouth)1 so the root canal system becomes “pulpless and infected.” During the first few months following pulp necrosis, a periapical radiolucency will not be evident (Figure 8-4) as this takes several months more to manifest. Within these first few months, the pulp is still considered necrotic but there are signs that it is infected, as outlined subsequently. This stage of the disease process (i.e., necrotic and infected pulp) is only present for a very short period of time. Typical symptoms—no pulp-related symptoms (i.e., no thermal sensitivity); may be no symptoms at all; any symptoms will be from the periapical tissues—hence, symptoms depend on the periapical status; may have pain associated with biting or pressure (depends on the periapical status); occasionally pain with heat that is temporarily relieved by applying very cold water/ice to the tooth. Clinical findings—may be caries, a restoration breaking down or a crack; tooth does not respond to pulp sensibility tests; may be tender to percussion (depends on the periapical status); may be some tooth discolouration. Radiographic findings—caries may be seen if extensive enough; usually have normal PDL space and lamina dura; sometimes a slightly widened PDL space and loss of lamina dura may be evident periapically. Associated periapical/periradicular conditions—may have clinically normal periapical tissues (in the early stages); may have primary acute apical periodontitis (if pain and tender to percussion); may have a primary acute apical abscess (if pain, tender to percussion, swelling, and localized collection of pus). Key findings for diagnosis—no response to pulp sensibility tests and no periapical changes seen radiographically. Distinguish from pulp necrosis with no signs of infection by the symptoms and the apical periodontitis. Distinguish from a pulpless and infected root canal system as there is no periapical radiolucency.

Pulpless and Infected Root Canal System

A root canal system that has a necrotic and infected pulp will rapidly (within one to two months) become pulpless and infected.1 A periapical radiolucency will then develop over the next few months (Figure 8-5). Hence, once a periapical radiolucency is present, it is safe to assume that the root canal system is pulpless and infected—at this stage, it should no longer should be called a necrotic and infected pulp. This condition should not be confused with a tooth that has had previous root canal treatment as specific terminology is used for those teeth (see subsequently). The term “pulpless and infected” is used to demonstrate that the tooth has no pulp because of the bacteria in the canal. Typical symptoms—no pulp-related symptoms (i.e., no thermal sensitivity); may be no symptoms at all; any symptoms will be from the periapical tissues—hence, symptoms depend on the periapical status; may be an occasional dull ache or “awareness of tooth” if chronic apical periodontitis or a chronic apical abscess is present; will have pain associated with biting or pressure if secondary acute apical periodontitis or a secondary acute apical abscess is present. Clinical findings—may be caries, a restoration breaking down or a crack; the tooth does not respond to pulp sensibility tests; may feel “different” on percussion if chronic periapical condition present; will be tender to percussion if acute periapical condition present; may have increased mobility if acute periapical condition present; may be some tooth discolouration. Radiographic findings—caries may be seen if extensive enough; a periapical radiolucency will be present. Associated periapical/periradicular conditions—may have any of the following—depending on the symptoms, clinical and radiographic findings: chronic apical periodontitis (no symptoms or only occasional ache); a chronic apical abscess (if draining sinus present); secondary acute apical periodontitis (if pain and tenderness to percussion); a secondary acute apical abscess (if pain tender to percussion, swelling, and localized collection of pus), or facial cellulitis (if facial swelling due to spreading infection). Key findings for diagnosis—no response to pulp sensibility tests and there will be a periapical radiolucency. Distinguish from a necrotic and infected pulp by the presence of a periapical radiolucency. Distinguish from pulp necrosis with no signs of infection as there is a periapical radiolucency. Distinguish from a tooth with previous endodontic treatment as there is no history or radiographic evidence of previous treatment.

Previous Endodontic Treatment with No Signs of Infection

There are various procedures that can be grouped as “endodontic treatment”—essentially any procedure that involves treatment of the pulp or root canal system. These include direct pulp capping, partial pulpotomy, pulpotomy, partial pulpectomy, root canal filling, root canal retreatment, and the commencement of root canal treatment (i.e., commenced but not completed). Separate diagnostic categories for each type of treatment are not required but when assessing teeth with previous endodontic treatment, the nature of that treatment should be included in the diagnosis. The term “no signs of infection” is used because it is not possible to categorically state that the tooth is “not infected,” based on the information obtained from a clinical and radiographic examination. It is known that radiographic signs of apical periodontitis (i.e., a radiolucency) take at least several months to be visible once a pulp or root canal system becomes infected1—hence, the lack of a radiolucency does not necessarily indicate the lack of an intracanal infection. It merely means that there were no signs of apical periodontitis (and hence no sign of root canal infection) at the time the radiograph was exposed (Figure 8-6). Typical symptoms—no symptoms; will have a history of some form of previous pulp/root canal treatment, such as: pulp capping, partial pulpotomy, pulpotomy, partial pulpectomy, root canal filling (on one or more occasions), or incomplete root canal treatment (e.g., if started as an emergency but not yet completed). Clinical findings—the coronal restoration is intact and “clinically satisfactory”; no caries, no cracks or fractures of tooth; no abnormal findings except the tooth may or may not respond to pulp sensibility tests (depends on type of previous pulp treatment, e.g., may respond if previous pulp cap, partial pulpotomy, or pulpotomy) and there may be some tooth discolouration. Radiographic findings—no caries evident; restoration appears satisfactory; no abnormal observations of tooth; normal PDL space and lamina dura; evidence of previous pulp treatment or root canal filling; if root canal filling present, it may or may not be technically satisfactory; other deficiencies or procedural errors may be evident in some cases but without associated radiolucency—for example: perforation, untreated canal, blocked canal, fractured file, incomplete root canal treatment, and so forth. Associated periapical/periradicular conditions—clinically normal periapical tissues. Key findings for diagnosis—history and/or radiographic evidence of previous pulp/root canal treatment, plus no symptoms, and no other abnormal findings. Distinguish from previous endodontic treatment with an infected root canal system as there is no periapical radiolucency and no signs indicating apical periodontitis. Distinguish from a pulpless, infected root canal system as there is a history or radiographic evidence of previous endodontic treatment.

Previous Endodontic Treatment with an Infected Root Canal System

Once a tooth with previous endodontic treatment develops a periapical radiolucency, then the root canal system should be considered to be infected (Figure 8-7). The endodontic treatment could be any procedure that involves treatment of the pulp or root canal—these include direct pulp capping, partial pulpotomy, pulpotomy, partial pulpectomy, root canal filling, root canal retreatment, and the commencement of root canal treatment (i.e., commenced but not completed). Separate diagnostic categories for each type of treatment are not required but when assessing teeth with previous endodontic treatment, the nature of that treatment should be included in the diagnosis. A tooth that has had root canal treatment commenced, but not completed, may still have a periapical radiolucency. This may represent a continuation of chronic apical periodontitis or the periapical tissues may be healing (but not completely healed). It is not possible to differentiate between these scenarios and hence it is safer to assume the root canal system may still be infected and to continue treating the tooth accordingly. Typical symptoms—any symptoms will be from the periapical tissues—hence, symptoms depend on the periapical status; may be an occasional dull ache or “awareness of tooth” if chronic apical periodontitis or a chronic apical abscess is present; will have pain associated with biting or pressure if secondary acute apical periodontitis or a secondary acute apical abscess is present; will have a history of some form of previous pulp/root canal treatment, such as pulp capping, partial pulpotomy, pulpotomy, partial pulpectomy, root canal filling (on one or more occasions), or incomplete root canal treatment (e.g., if started as an emergency but not yet completed). Clinical findings—may be caries, a restoration breaking down or a crack; the tooth does not respond to pulp sensibility tests; may feel “different” on percussion if chronic periapical condition present; will be tender to percussion if acute periapical condition present; may have increased mobility if acute periapical condition present; may be some tooth discolouration. Radiographic findings—caries may be seen if extensive enough; a periapical radiolucency will be present; evidence of previous pulp treatment or root canal filling; if root canal filling present, it may or may not be technically satisfactory; other deficiencies or procedural errors may be evident in some cases and may have an associated radiolucency (e.g., perforation, untreated canal, blocked canal, fractured file, incomplete root canal treatment, etc.). Associated periapical/periradicular conditions—may have any of the following depending on the symptoms, clinical and radiographic findings: chronic apical periodontitis (no symptoms or only occasional ache), a chronic apical abscess (if draining sinus present), secondary acute apical periodontitis (if pain and tenderness to percussion), a secondary acute apical abscess (if pain, tender to percussion, swelling, and localized collection of pus), or facial cellulitis (if facial swelling due to spreading infection). Key findings for diagnosis—history and/or radiographic evidence of previous pulp/root canal treatment, plus the presence of a periapical radiolucency. Distinguish from previous endodontic treatment without signs of infection as there is a periapical radiolucency. Distinguish from a pulpless and infected root canal system as there is a history and/or radiographic evidence of previous endodontic treatment.

Pulp Atrophy

Atrophy of the pulp is a normal physiologic process that occurs with age. Clinically, it is difficult to distinguish whether this is present but it is likely in older patients. This condition does not require any specific treatment but it is important for clinicians to recognize that it does occur as it can affect the ability to diagnose the pulp status of some teeth.

Typical symptoms—no symptoms. Clinical findings—usually no abnormal findings but the tooth may have a restoration; the tooth may or may not respond to pulp sensibility tests; the patient is usually elderly. Radiographic findings—usually no abnormal observations of the tooth but it may have a restoration; some pulp canal calcification (PCC) may be evident; normal PDL space and lamina dura. Associated periapical/periradicular conditions—clinically normal periapical tissues. Key findings for diagnosis—no symptoms and no abnormal findings.

Pulp Canal Calcification

PCC could be considered as a radiographic observation of the appearance (especially the width) of the root canal(s) rather than as a distinct condition of the pulp or root canal system. It is not necessarily indicative of a disease process or pathological state of the tooth and therefore it is included as a “condition” rather than as a “disease.” It is included in this classification of root canal conditions as its presence affects the management of the tooth—since it may affect the diagnostic process (e.g., pulp tests are less reliable) as well as the treatment (e.g., difficulty locating and negotiating the root canal). Clinicians should recognize that the pulp contained within a calcified canal can be normal or diseased, or the canal may be pulpless and infected, and so forth11—that is, all pulp and root canal conditions could be associated with PCC (Figure 8-8). Hence, the complete diagnosis of a tooth with PCC must include the diagnosis of the pulp or root canal condition as well as the PCC.11 The term “PCC” is the preferred term.11 Some clinicians and authors use the term “pulp canal obliteration” but this is not accurate and hence not appropriate. The word “obliterate” is defined as “complete removal or destroying all traces of.”22 When a pulp undergoes calcification (defined as deposition of calcific material), it is not possible for the root canal to be completely removed or destroyed. There will always be a very small, narrow canal present even when the canal cannot be seen radiographically. The remaining canal may only be a few microns in width that is enough for several cells and it may or may not be possible to negotiate it with a root canal file; however, the canal still exists.11 Hence, it is more appropriate to refer to the process as “PCC” as this accurately describes what is truly happening inside the tooth. Typical symptoms—symptoms will depend on the pulp or root canal condition—any of the following may be present with the typical symptoms as outlined earlier: clinically normal pulp, chronic reversible pulpitis, acute reversible pulpitis, chronic irreversible pulpitis, acute irreversible pulpitis, pulp necrobiosis, pulp necrosis with no signs of infection, necrotic and infected pulp, pulpless and infected root canal system, previous endodontic treatment with no signs of infection, previous endodontic treatment with an infected root canal system, pulp atrophy. Clinical findings—clinical findings will depend on the pulp or root canal condition—with the typical clinical findings for each condition as outlined earlier; if a clinically normal pulp, then response to pulp sensibility testing may be variable, as follows: usually no response to a cold test, may or may not respond to an electric pulp test; if any form of pulpitis present, then the tooth should respond to cold pulp sensibility testing but some cases do not respond; the tooth should respond to an electric pulp test; if pulp necrosis, pulpless and infected or previous endodontic treatment, then there will be no response to pulp sensibility tests. Radiographic findings—PCC is evident—this may be partial (vertically and/or horizontally) or it may involve the entire pulp space; other radiographic observations will depend on the pulp or root canal condition—with the typical radiographic observations for each condition as outlined earlier. Associated periapical/periradicular conditions—this will depend on the pulp or root canal condition with the various possible periapical/periradicular condition(s) as outlined earlier for each particular pulp/root canal condition. Key findings for diagnosis—radiographic evidence of PCC. Distinguish from other conditions that do not respond to pulp sensibility tests by the symptoms, other clinical and radiographic findings, plus the associated periapical/periradicular condition(s).

Pulp Hyperplasia

Pulp hyperplasia almost exclusively occurs in young teeth with an abundant blood supply and a large carious lesion.11It is essentially an overgrowth of granulation tissue and it appears as a polyp arising from the pulp. In some cases, it may appear to be connected to the gingival tissues. Typical symptoms—often no symptoms; some cases may have pain when eating if the hyperplastic tissue is contacted by food, drinks, and so forth; some cases may bleed when the hyperplastic tissue is touched, brushed, and so forth; some cases will have the typical symptoms of pulpitis, as outlined earlier—the pulpitis can be chronic reversible pulpitis, acute reversible pulpitis, chronic irreversible pulpitis, or acute irreversible pulpitis. Clinical findings—a “pulp polyp” is evident, within a large carious cavity where the pulp has been exposed by the caries; the pulp polyp may bleed on probing; the pulp polyp may or may not be sensitive to probing; the tooth will respond to pulp sensibility tests with the nature of the response depending on the type of pulpitis present, as outlined earlier; the pulp polyp will sometimes appear to be continuous with the gingival tissues if the cavity extends to the gingivae. Radiographic findings—large carious lesion evident; other radiographic observations will depend on the pulp or root canal condition—with the typical radiographic observations for each condition as outlined earlier; as pulp hyperplasia is usually a long-standing problem, there is likely to be some minor widening of the PDL space or condensing osteitis, with both appearances indicating chronic apical periodontitis. Associated periapical/periradicular conditions—the associated periapical/periradicular condition(s) will depend on the type of pulpitis present, as outlined earlier; typically there will be chronic apical periodontitis. Key findings for diagnosis—clinical appearance of a “pulp polyp.” Distinguish from the various forms of pulpitis without hyperplasia by the presence of the pulp polyp. Distinguish from all types of infected root canal systems by the symptoms, the clinical appearance of a pulp polyp and the response to pulp sensibility tests.

periapical/periradicular conditions

This section will describe each periapical/periradicular condition listed in Table 8-2 to guide clinicians in the diagnostic process with a brief description of the typical symptoms reported by the patient, the typical clinical findings found on examination and testing of the tooth, the typical radiographic observations seen on periapical radiographs, the typical pulp/root canal conditions associated with each periapical/periradicular condition, the key findings that lead to the particular diagnosis, and the findings that distinguish each condition from other similar conditions. The term “periapical” is commonly used by most practitioners although “periradicular” is more accurate. Most periradicular conditions manifest in the periapical tissues because these tissues are adjacent to the apical foramen of the root canal(s). However, the same responses can manifest in the PDL and adjacent bone anywhere along the length of the root surface. Lateral canals are the same as the main canal in that they are part of the root canal system and they can contain inflamed pulp tissue that may become necrotic and eventually the lateral canals become pulpless and infected. In addition, pulp and root canal conditions can cause other periradicular conditions such as various forms of external root resorption. Hence, the term “periradicular” is more comprehensive, more accurate and more appropriate when discussing conditions caused by pulp and root canal conditions. The various forms of external resorption will not be discussed in this chapter as they are discussed in detail in Chapter 15.

Clinically Normal Periapical/Periradicular Tissues

The term “clinically normal” is used when there are no signs or symptoms to suggest that any form of disease is occurring. The term “clinically” is used since the periapical/periradicular tissues may not be histologically normal and/or may have some degree of inflammation or fibrosis (scarring) as a result of previous injury or stimuli (such as some form of apical periodontitis, etc.). However, for all intents and purposes, the tooth does not have any periapical/periradicular pathosis that requires treatment. Typical symptoms—no symptoms from the periapical or periradicular tissues; if there are any symptoms, these will be from the pulp—hence, symptoms depend on the status of the pulp. Clinical findings—no abnormal findings; no tenderness to percussion; no tenderness to palpation; no increased mobility; various pulp and/or root canal conditions may be present—any clinical findings will depend on what condition is present; the tooth may or may not respond to pulp sensibility tests—this depends on the state of the pulp/root canal system. Radiographic findings—no abnormal observations of the tooth; normal PDL space and lamina dura; some cases may have evidence of previous endodontic treatment. Associated pulp/root canal conditions—may have any of the following—depends on the symptoms, clinical and radiographic findings: clinically normal pulp, reversible pulpitis—chronic or acute, irreversible pulpitis— chronic or acute, pulp necrobiosis, necrosis with no signs of infection, necrotic and infected pulp, previous endodontic treatment with no signs of infection, pulp atrophy, PCC, pulp hyperplasia, internal surface resorption, internal inflammatory resorption, or internal replacement resorption. Key findings for diagnosis—no symptoms from the periapical/periradicular tissues and no abnormal findings.

Primary Acute Apical Periodontitis

The term “apical periodontitis” implies inflammation of the periapical tissues. When this first commences, there will not be a radiolucency as it takes some time for the bone (and possibly some of the tooth) to be resorbed to the extent where it is visible radiographically. The first stage of apical periodontitis is called “primary acute apical periodontitis”2,5 and its key feature is the lack of a radiolucency (Figure 8-4), yet there is considerable pain. The pain occurs, and is usually intense, because the inflammation is confined within the hard bony tissues and the PDL where there is no space for the swelling, exudate, and so forth to expand. Typical symptoms—the pain has only been present for a short time (e.g., a few days or less); the pain is usually quite severe; pain to biting and pressure on the tooth; pain to touch the tooth—even with light pressure; may be pain due to acute irreversible pulpitis if present; occasionally may have pain due to acute reversible pulpitis. Clinical findings—may be caries, a restoration breaking down or a crack; severe pain to percussion; pain when pushing on the tooth; usually no response to pulp sensibility tests—unless acute reversible pulpitis or acute irreversible pulpitis in which case the tooth will respond to cold pulp testing which reproduces the thermal sensitivity pain that the patient will also complain of; sometimes the tooth is in traumatic occlusion due to being extruded from its normal position as a result of the periapical inflammation being constrained by the hard bone structure that has not yet resorbed to create space. Radiographic findings—caries may be seen if extensive enough; normal PDL space and lamina dura; a slightly widened PDL space may be evident if the tooth is extruded from its normal position; some cases may have evidence of previous endodontic treatment; occasionally may see a radiolucency within the tooth root indicating internal inflammatory resorption. Associated pulp/root canal conditions—usually due to an infected root canal system—may have any of the following depending on symptoms, clinical and radiographic findings: pulp necrobiosis, a necrotic and infected pulp, previous endodontic treatment with an infected root canal system, or internal inflammatory resorption; may be associated with acute irreversible pulpitis; rarely associated with acute reversible pulpitis. Key findings for diagnosis—there are no radiographic periapical changes, the pain is recent and severe; there is pain when touching the tooth, with pressure and on percussion. Distinguish from secondary acute apical periodontitis by the lack of radiographic signs of any periapical changes. Distinguish from chronic apical periodontitis by the lack of radiographic signs of any periapical changes, plus the presence of pain and the tenderness to percussion. Distinguish from a primary acute apical abscess by the lack of swelling. Distinguish from a secondary acute apical abscess by the lack of swelling. Distinguish from a chronic apical abscess by the lack of a draining sinus.

Secondary Acute Apical Periodontitis

Secondary acute apical periodontitis occurs when there has been chronic apical periodontitis or a chronic apical abscess present for some time so there is also a periapical radiolucency (Figure 8-7). Secondary acute apical periodontitis is usually a result of an imbalance occurring between the intra-canal infection and the host defence system whereby some bacteria and/or their endotoxins escape through the apical foramen and cause an acute exacerbation of the chronic inflammatory response that has been present for some time. The patient then becomes aware of symptoms. This process may occur on numerous occasions (e.g., patient reports that the pain “comes and goes”) so in effect it is not necessarily just the second time that an acute inflammatory reaction occurs but every time that it changes from chronic to acute inflammation. The process is dynamic and the secondary acute apical periodontitis can return to being chronic apical periodontitis if the environmental conditions are suitable and the host defence response is adequate. Typical symptoms—the pain has only been present for a short time (e.g., a few days or less); the pain is usually quite severe; pain to biting or pressure on the tooth; no thermal sensitivity. Clinical findings—may be caries, a restoration breaking down or a crack; very tender to percussion; no response to pulp sensibility tests; may be tender to palpation. Radiographic findings—caries may be seen if extensive enough; a periapical radiolucency is present—this indicates chronic apical periodontitis has been present for some time; some cases may have evidence of previous endodontic treatment; occasionally may see a radiolucency within the tooth root indicating internal inflammatory resorption. Associated pulp/root canal conditions—will be due to an infected root canal system, hence, may have any of the following depending on the symptoms, clinical and radiographic findings: pulpless and infected root canal system, previous endodontic treatment with an infected root canal system, or internal inflammatory resorption. Key findings for diagnosis—there is a periapical radiolucency, the pain is recent and severe; pain with pressure and on percussion. Distinguish from primary acute apical periodontitis by the presence of a periapical radiolucency.

Distinguish from chronic apical periodontitis by the pain and the tenderness to percussion. Distinguish from a primary acute apical abscess by the lack of swelling. Distinguish from a secondary acute apical abscess by the lack of swelling. Distinguish from a chronic apical abscess by the lack of a draining sinus.

Chronic Apical Periodontitis

After an initial period of primary acute apical periodontitis, and if the tooth has not been treated, the periapical inflammation can become chronic. After several months, this usually manifests as a periapical radiolucency (Figure 8-5). Bone is resorbed to create space for the inflammatory reaction to occur so there are usually no, or only occasional mild symptoms or an occasional “awareness” of the tooth feeling different to the other teeth. Typical symptoms—usually no symptoms; the patient may report a history of occasional “awareness” of the tooth feeling different; the patient may report a history of previous pulp-related symptoms some time ago; the patient may report a history of previous endodontic treatment. Clinical findings—may be caries, a restoration breaking down or a crack; the tooth is not tender to percussion but will sometimes feel “different” to percussion; no response to pulp sensibility tests. Radiographic findings—caries may be seen if extensive enough; a periapical radiolucency will be present; some cases may have evidence of previous endodontic treatment; occasionally may see a radiolucency within the tooth root indicating internal inflammatory resorption. Associated pulp/root canal conditions—will be due to an infected root canal system—may have any of the following depending on the symptoms, clinical and radiographic findings: a pulpless and infected root canal system, previous endodontic treatment with an infected root canal system, or internal inflammatory resorption. Key findings for diagnosis—there is a periapical radiolucency and no pain or only occasional “awareness” of the tooth. Distinguish from primary acute apical periodontitis by the presence of a periapical radiolucency. Distinguish from secondary acute apical periodontitis by the lack of symptoms. Distinguish from a primary acute apical abscess by the lack of swelling and lack of symptoms. Distinguish from a secondary acute apical abscess by the lack of swelling and lack of symptoms. Distinguish from a chronic apical abscess by the lack of a draining sinus.

Condensing Osteitis

Condensing osteitis is a form of chronic apical periodontitis but it manifests as a radiopacity instead of a radiolucency(Figure 8-9). It is most commonly associated with teeth that have long-standing pulpitis—usually, or at least initially, chronic reversible pulpitis.5 Hence, it is essentially an extension of the inflammatory response that began in the pulp or it is an indication that the periapical tissues have been irritated for some time with the result that more bone is laid down rather than being resorbed. The chronic reversible pulpitis may have episodes of acute reversible pulpitis that may be the time when the patient presents for treatment. Alternatively, the chronic reversible pulpitis may develop into chronic irreversible pulpitis, acute irreversible pulpitis or pulp necrosis with infection. Also, the root canal system may become pulpless and infected. The state of the pulp/root canal will depend on when the patient presents for treatment whereas the increased bone density that is evident radiographically may take many years to resolve and may not resolve at all. When the root canal system becomes infected, a radiolucency will typically develop immediately adjacent to the root apex and this may be surrounded by the sclerotic bone of the condensing osteitis, thus appearing as both radiopacity and radiolucency. Typical symptoms—no symptoms from the periapical or periradicular tissues; no tenderness to percussion; any symptoms will be from the pulp—hence, symptoms depend on the status of the pulp; usually associated with longstanding chronic reversible pulpitis—hence symptoms will be typical of this condition (see earlier); the chronic reversible pulpitis may progress to acute reversible pulpitis, chronic irreversible pulpitis or acute irreversible pulpitis by the time the patient presents for treatment—hence the symptoms vary according to the stage of pulp disease. Clinical findings—may be caries, a restoration breaking down or a crack; the tooth is not tender to percussion but may occasionally feel “different” to percussion; the tooth will usually respond to pulp sensibility tests (the nature of the response depends on the state of the pulp) unless the pulp state has progressed to pulp necrosis, and so forth. Radiographic findings—caries may be seen if extensive enough; the periapical region appears more radiopaque than the surrounding bone due to increased bone deposition (i.e., condensing osteitis); some cases may present later after the pulp has necrosed and the root canal system has become infected with various forms of apical periodontitis or apical abscesses—in these cases, some condensing osteitis may still be evident radiographically and there may be a widened PDL space or a radiolucency surrounded by the denser bone of condensing osteitis. Associated pulp/root canal conditions—will be long-standing chronic reversible pulpitis initially; the chronic reversible pulpitis may progress to any of the following depending on the symptoms, clinical and radiographic findings: acute reversible pulpitis, chronic irreversible pulpitis or acute irreversible pulpitis; some cases may present later after the pulp has necrosed and the root canal system has become pulpless and infected with various forms of apical periodontitis or apical abscesses—in these cases, some condensing osteitis may still be evident radiographically but the process has changed to bone resorption instead of increased bone deposition. Key findings for diagnosis—there is a radiopacity indicating denser bone (i.e., condensing osteitis) present in the periapical region. Distinguish from primary acute apical periodontitis by the presence of the radiopacity and lack of symptoms. Distinguish from secondary acute apical periodontitis by the presence of the radiopacity and lack of symptoms. Distinguish from chronic apical periodontitis by the presence of the radiopacity (although it should be noted that condensing osteitis is essentially a form of chronic apical periodontitis). Distinguish from a primary acute apical abscess by the lack of swelling and lack of symptoms, and the presence of the radiopacity. Distinguish from a secondary acute apical abscess by the lack of swelling and lack of symptoms, and the presence of the radiopacity. Distinguish from a chronic apical abscess by the lack of a draining sinus and the presence of the radiopacity.

Primary Acute Apical Abscess

An abscess is defined as a “localized collection of pus.” When this occurs in the early stages of the periapical disease process, there will not be a radiolucency as it takes some time for the bone (and possibly some of the tooth) to be resorbed to the extent where it is visible radiographically (Figure 8-10). Hence, an abscess in its early stages is called “primary acute apical abscess”2,5 and its key feature is the lack of a radiolucency, yet there is considerable pain. The pain occurs, and is usually intense, because the inflammation and the pus are confined within the hard bony tissues and the PDL where there is no space for the pus and swelling to expand. Typical symptoms—the pain has only been present for a short time (e.g., a few days or less); the swelling has had rapid onset (e.g., hours, or less than one day); pus will be present; the pain is severe; pain to biting and pressure on the tooth; pain to touch the tooth—even with light pressure; occasionally the patient may complain of feeling unwell and having fever. Clinical findings—may be caries, a restoration breaking down or a crack; swelling associated with the tooth;severe pain to percussion; pain when pushing on the tooth; pain on palpation; no response to pulp sensibility tests; usually the tooth is in traumatic occlusion due to being extruded from its normal position; occasionally the patient may have fever, malaise and lymphadenopathy. Radiographic findings—caries may be seen if extensive enough; normal PDL space and lamina dura; a slightly widened PDL space may be evident if the tooth is extruded from its normal position; some cases may have evidence of previous endodontic treatment; occasionally may see a radiolucency within the tooth root indicating internal inflammatory resorption. Associated pulp/root canal conditions—will be due to an infected root canal system—hence, may have any of the following depending on the symptoms, clinical and radiographic findings: a necrotic and infected pulp, previous endodontic treatment with an infected root canal system, or internal inflammatory resorption. Key findings for diagnosis—there are no radiographic periapical changes, there is swelling present, the pain is recent and severe, and there is pain when touching the tooth, with pressure and on percussion. Distinguish from primary acute apical periodontitis by the presence of the swelling and pus. Distinguish from secondary acute apical periodontitis by the lack of periapical radiolucency, and the presence of the swelling and pus. Distinguish from chronic apical periodontitis by the lack of periapical radiolucency, and the presence of pain, swelling tenderness to percussion, and pus. Distinguish from a secondary acute apical abscess by the lack of periapical radiolucency. Distinguish from a chronic apical abscess by the lack of a draining sinus and no periapical radiolucency.

Secondary Acute Apical Abscess

A secondary acute apical abscess occurs when there has been chronic apical periodontitis or a chronic apical abscess present for some time so there is also a radiolucency (Figure 8-11). A secondary acute apical abscess is usually a result of an imbalance occurring between the intra-canal infection and the host defense system whereby some bacteria and/or their endotoxins (or both) escape through the apical foramen and cause an acute exacerbation of the chronic inflammatory response that has been present for some time. The acute exacerbation will be in the form of a localized collection of pus (i.e., an abscess). It may also occur when the draining sinus of a chronic apical abscess closes or becomes blocked so the pus cannot drain. Typical symptoms—the pain has only been present for a short time (e.g., a few days or less); the swelling has had rapid onset (e.g., hours, or less than one day); pus will be present; the pain is usually quite severe; pain to biting or pressure on the tooth; no thermal sensitivity; occasionally the patient may complain of feeling unwell and having fever. Clinical findings—may be caries, a restoration breaking down or a crack; the tooth is very tender to percussion; no response to pulp sensibility tests; tender to palpation; occasionally the patient may have fever, malaise and lymphadenopathy. Radiographic findings—caries may be seen if extensive enough; there will be a periapical radiolucency present—indicates chronic apical periodontitis has been present for some time before the abscess developed; some cases may have evidence of previous endodontic treatment; occasionally may see a radiolucency within the tooth root indicating internal inflammatory resorption. Associated pulp/root canal conditions—will be due to an infected root canal system—hence, may have any of the following depending on the symptoms, clinical and radiographic findings: a pulpless and infected root canal system, previous endodontic treatment with an infected root canal system, or internal inflammatory resorption. Key findings for diagnosis—there is a periapical radiolucency, swelling is present, the pain is recent and severe, and there is pain when touching the tooth, with pressure and on percussion. Distinguish from primary acute apical periodontitis by the presence of a periapical radiolucency and the swelling. Distinguish from secondary acute apical periodontitis by the presence of the swelling and if the patient has fever, malaise, and so forth. Distinguish from chronic apical periodontitis by the presence of swelling, pain, fever, and so forth. Distinguish from a primary acute apical abscess by the presence of a periapical radiolucency. Distinguish from a chronic apical abscess by the lack of a draining sinus and the presence of swelling and symptoms.

Chronic Apical Abscess

A chronic apical abscess is characterized by the presence of a draining sinus5—either intra-orally or extra-orally on the face (Figure 8-12). The draining sinus may “come and go” and this will be dependent on whether there is pus to drain.Hence, the condition may oscillate between being chronic apical periodontitis and a chronic apical abscess. Typical symptoms—usually there are no symptoms; some patients may be aware of the presence of a draining sinus (they may refer to it as a “gum boil,” “lump,” “ulcer,” etc.); the draining sinus is usually intra-oral (on the oral mucosa) but may be extra-oral (on the face); the patient may report a history of occasional “awareness” of the tooth feeling different; the patient may report a history of previous pulp-related symptoms some time ago; may have history of previous endodontic treatment. Clinical findings—may be caries, a restoration breaking down or a crack; the tooth is not tender to percussion; may feel “different” to percussion; no response to pulp sensibility tests; draining sinus evident—intra-oral or extra-oral; palpation or pressure on the tissues overlying the periapical region may cause pus to exude from the draining sinus; can often insert a gutta-percha point into the draining sinus to trace it radiographically. Radiographic findings—caries may be seen if extensive enough; there is a periapical radiolucency present; a gutta-percha point inserted into the draining sinus can trace its origin to the infected tooth; some cases may have evidence of previous endodontic treatment; occasionally may see a radiolucency within the tooth root indicating internal inflammatory resorption. Associated pulp/root canal conditions—will be due to an infected root canal system—hence, may have any of the following depending on the symptoms, clinical and radiographic findings: a pulpless and infected root canal system, previous endodontic treatment with an infected root canal system, or internal inflammatory resorption. Key findings for diagnosis—there is a draining sinus, a periapical radiolucency and no pain or only occasional “awareness.” Distinguish from secondary acute apical periodontitis by the presence of the draining sinus and lack of symptoms. Distinguish from chronic apical periodontitis by the presence of the draining sinus. Distinguish from a secondary acute apical abscess by the presence of the draining sinus, and the lack of swelling and symptoms. Distinguish from a foreign body reaction by the presence of the draining sinus and the lack of radiographic evidence of a foreign body (but some foreign bodies may not be radiopaque and therefore may not be evident radiographically).

Facial Cellulitis

Facial cellulitis occurs when an infected root canal system develops a periapical abscess (usually a secondary acute apical abscess, although it could be a primary acute apical abscess) and the infection spreads between the fascial planes of the muscles of the face, head, and/or neck (Figure 8-13).It is a spreading infection and it can be superficial or deep. In either case, it can be life-threatening if the resultant swelling restricts the airway. Patients with facial cellulitis require immediate and aggressive treatment—that is, not just oral antibiotic therapy but active dental treatment to remove the source of the bacteria. They often require hospitalisation and even management in an intensive care unit to protect the airway and provide life support in severe cases. For more details, see Chapter 30. Typical symptoms—facial swelling that is increasing in size—often rapidly; the swelling has had rapid onset (e.g., hours); the patient has considerable pain and discomfort; the pain has only been present for a short time (usually less than 24 hours); there is pain to biting or pressure on the tooth; no thermal sensitivity; the patient has fever and feels unwell. Clinical findings—facial swelling is evident; may be caries, a restoration breaking down or a crack; very tender to percussion; no response to pulp sensibility tests; tender to palpation; the patient has fever, malaise and lymphadenopathy; severe cases may have airway involvement; typically also have localized signs of a secondary acute apical abscess as the abscess usually occurs before the infection spreads to become facial cellulitis.

Radiographic findings—caries may be seen if extensive enough; there is a periapical radiolucency present— indicates chronic apical periodontitis has been present for some time before the abscess and facial cellulitis developed; some cases may have evidence of previous endodontic treatment; occasionally may see a radiolucency within the tooth root indicating internal inflammatory resorption. Associated pulp/root canal conditions—will be due to an infected root canal system, hence, may have any of the following depending on the symptoms, clinical and radiographic findings: a pulpless and infected root canal system, previous endodontic treatment with an infected root canal system, or internal inflammatory resorption. Key findings for diagnosis—there is facial swelling of rapid onset, the swelling is spreading, the patient has fever, feels unwell, has a periapical radiolucency, and pain with pressure and percussion. Distinguish from primary acute apical periodontitis by the presence of a periapical radiolucency, facial swelling, fever, and malaise. Distinguish from secondary acute apical periodontitis by the presence of facial swelling, fever, and malaise. Distinguish from chronic apical periodontitis by the pain, facial swelling and the tenderness to percussion. Distinguish from a primary acute apical abscess by the presence of a periapical radiolucency, facial swelling, fever, and malaise. Distinguish from a secondary acute apical abscess by the swelling spreading throughout the face, and so forth. Distinguish from a chronic apical abscess by the lack of a draining sinus and the presence of pain and facial swelling.

Extra-Radicular Infection

An extra-radicular infection occurs when bacteria establish colonies on the external root surface within the periapical region. It is usually a sequel to an infected root canal system and the extra-radicular bacteria are similar to those found in infected root canals.2,23–25 Actinomyces species are often found in these cases (Figure 8-14). Extra-radicular infections cannot be diagnosed clinically and they can only be diagnosed histologically. However, clinicians should recognize that this condition does occur and it should be part of the differential diagnosis of a persistent radiolucency following endodontic treatment. Typical symptoms—may have no symptoms; may be associated with persistent swelling and/or draining sinus; patient may report a history of occasional “awareness” of the tooth feeling different; history of recent or current root canal treatment that is not resolving the problem. Clinical findings—may be caries, a restoration breaking down or a crack; tooth has signs of recent root canal treatment (e.g., access cavity restoration); not tender to percussion or may feel “different” to percussion; no response to pulp sensibility tests; some cases will have a persistent draining sinus despite recent or ongoing root canal treatment—the draining sinus may be intraoral or extra-oral; palpation or pressure on the tissues overlying the periapical region may cause pus to exude from the draining sinus, if present; can insert a gutta percha point into the draining sinus, if present, to trace it radiographically. Radiographic findings—caries may be seen if extensive enough; a periapical radiolucency is present; the radiolucency is persisting or may be increasing in size despite recent root canal treatment; root canal filling or intracanal dressing evident; gutta percha point inserted into the draining sinus, if present, can trace its origin to the affected tooth. Associated pulp/root canal conditions—usually considered as part of the differential diagnosis of a persistent radiolucency despite recent or ongoing endodontic treatment—hence, it will initially be associated with an infected root canal system; may be associated with previous endodontic treatment with an infected root canal system—treatment may be incomplete with an intracanal medicament in place; or treatment may be complete with a root canal filling evident. Key findings for diagnosis—a periapical radiolucency and no pain, typically has had recent root canal treatment without resolution of the periapical radiolucency. Distinguish from a foreign body reaction, a periapical pocket cyst, a periapical true cyst, and a periapical scar by histological examination of a biopsy specimen.

Foreign Body Reaction

A foreign body reaction is an inflammatory response to a foreign material within the periapical tissues.2,26,27 The most common foreign material is excess root filling material, such as gutta percha or root canal cement that has been extruded through the apical foramen.28,29 Radiographically, foreign body reactions usually appear as a periapical radiolucency surrounding some radiopaque material (Figure 8-15) but there have been reports of other materials that are not radiopaque—such as talcum powder and food.29 Foreign body reactions cannot be diagnosed clinically and they can only be diagnosed histologically. However, clinicians should recognize that this condition does occur and it should be part of the differential diagnosis of a persistent radiolucency following endodontic treatment. Typical symptoms—usually no symptoms; the patient may report a history of occasional “awareness” of the tooth feeling different; history of recent or current endodontic treatment without resolution of the periapical radiolucency and/or symptoms. Clinical findings—the tooth has signs of recent root canal treatment (e.g., access cavity restoration); the tooth is not tender to percussion or may feel “different” to percussion; no response to pulp sensibility tests. Radiographic findings—a periapical radiolucency is present; the radiolucency is persisting or may be increasing in size despite recent root canal treatment; root canal filling or intracanal dressing evident; radiopaque material may be seen in the periapical tissues; some cases may be due to materials that are not radiopaque and therefore not evident radiographically. Associated pulp/root canal conditions—usually considered as part of the differential diagnosis of a persistent radiolucency despite recent or ongoing endodontic treatment—hence, it will initially be associated with an infected root canal system; may be associated with previous endodontic treatment with an infected root canal system—treatment may be incomplete with an intracanal medicament in place; or the treatment may be complete with a root canal filling evident. Key findings for diagnosis—there is a periapical radiolucency; usually no pain; typically has had root canal treatment without resolution of the periapical radiolucency; many cases have radiopaque material present within the periapical radiolucency. Distinguish from an extra-radicular infection, a periapical pocket cyst, a periapical true cyst, and a periapical scar by histological examination of a biopsy specimen.

Periapical Pocket Cyst

A cyst is a sac-like structure lined by epithelium and containing fluid or semisolid material. Nair2,30,31 has reported and defined two types of periapical cysts—pocket cyst and true cyst. Both are essentially forms of chronic apical periodontitis that develop as a sequel to an infected root canal system but they have different histological appearances. A pocket cyst has an opening that communicates with the root canal system (Figure 8-16), hence it is not a true cyst according to the definition. It is believed that pocket cysts are likely to heal after the root canal system has been treated, but if no treatment is provided a pocket cyst may “break away” from the root canal and the tooth apex, and the opening closes to become a “true cyst.”

Periapical pocket cysts and periapical true cysts cannot be differentiated clinically or radiographically from other periapical conditions that manifest as radiolucencies. In the past, many practitioners have erroneously thought that welldefined borders of the radiolucency indicated a cyst but this is only indicative of a slowly developing lesion. A diffuse border is more likely to indicate a rapidly developing lesion. Likewise, the size of the radiolucency is not indicative of a cyst if it is large—since apical periodontitis, abscesses and cysts can be small or large. A large radiolucency is more likely to indicate a long-standing problem. For more details, see Chapter 6. Periapical pocket cysts cannot be diagnosed clinically and can only be diagnosed histologically. However, clinicians should recognize that this condition does occur and it should be part of the differential diagnosis of a persistent radiolucency following endodontic treatment.

Typical symptoms—usually no symptoms; may have symptoms if the cyst has become infected (e.g., becomes an acute apical abscess, chronic apical abscess or extraradicular infection); the patient may report a history of occasional “awareness” of the tooth feeling different; usually a history of recent or current endodontic treatment without resolution of the periapical radiolucency and/or symptoms. Clinical findings—may be caries, a restoration breaking down or a crack; the tooth has signs of recent root canal treatment (e.g., access cavity restoration); the tooth is not tender to percussion or palpation (unless it has become infected) or it may feel slightly “different” to percussion; no response to pulp sensibility tests. Radiographic findings—caries may be seen if extensive enough; a periapical radiolucency is present; the radiolucency is persisting or may be increasing in size despite recent endodontic treatment; root canal filling or intracanal dressing evident. Associated pulp/root canal conditions—usually considered as part of the differential diagnosis of a persistent radiolucency despite recent or ongoing endodontic treatment—hence, it will initially be associated with an infected root canal system; may be associated with previous endodontic treatment with an infected root canal system—treatment may be incomplete with an intracanal medicament in place; or the treatment may be complete with a root canal filling evident. Key findings for diagnosis—no symptoms and no abnormal findings; there is a periapical radiolucency and no pain, typically has had root canal treatment without resolution of the periapical radiolucency. Distinguish from an extra-radicular infection, a foreign body reaction, a periapical true cyst and a periapical scar by histological examination of a biopsy specimen.

Periapical True Cyst

As discussed earlier, Nair2,30,31 has reported and defined two types of periapical cysts—pocket cyst and true cyst. A true cyst has a complete epithelial lining (Figure 8-17) and contains fluid and often cholesterol crystals. It is a self-propagating lesion that is no longer dependent on the root canal system being infected. Epithelium (completely lining the cyst; no communication with the root canal system) Cystic Lumen (containing fluid ± cholesterol crystals) FIGURE 8-17 Schematic representation of a periapical true cyst. There is no communication between the cyst lumen and the root canal system (adapted from Abbott3). Hence, root canal treatment alone will not resolve a periapical true cysts and surgical removal will be necessary. As also discussed earlier, periapical pocket cysts and periapical true cysts cannot be differentiated clinically or radiographically from other periapical conditions that manifest as radiolucencies. The size of the radiolucency and the appearance of the borders are not specific diagnostic signs that can be used to diagnose a true cyst. Periapical true cysts cannot be diagnosed clinically and can only be diagnosed histologically. However, clinicians should recognize that this condition does occur and it should be part of the differential diagnosis of a persistent radiolucency following endodontic treatment. Typical symptoms—usually no symptoms; may have symptoms if the cyst has become infected (e.g., becomes an acute apical abscess, chronic apical abscess or extra-radicular infection); the patient may report a history of occasional “awareness” of the tooth feeling different; usually a history of recent or current endodontic treatment without resolution of the periapical radiolucency and/or symptoms. Clinical findings—may be caries, a restoration breaking down or a crack; the tooth has signs of recent root canal treatment (e.g., access cavity restoration); not tender to percussion or palpation (unless it has become infected) or it may feel slightly “different” to percussion; no response to pulp sensibility tests. Radiographic findings—caries may be seen if extensive enough; a periapical radiolucency is present; the radiolucency is persisting or may be increasing in size despite recent endodontic treatment; root canal filling or intracanal dressing evident. Associated pulp/root canal conditions—usually considered as part of the differential diagnosis of a persistent radiolucency despite recent or ongoing endodontic treatment—hence, it will initially be associated with an infected root canal system; may be associated with previous endodontic treatment with an infected root canal system—treatment may be incomplete with an intracanal medicament in place; or the treatment may be complete with a root canal filling evident.

Key findings for diagnosis—no symptoms and no abnormal findings; there is a periapical radiolucency and no pain; typically has had root canal treatment without resolution of the periapical radiolucency. Distinguish from an extra-radicular infection, a foreign body reaction, a periapical pocket cyst and a periapical scar by histological examination of a biopsy specimen.

Periapical Scar

A periapical scar is not a disease or a pathological condition. It is a healing response where fibrous, connective tissue forms instead of bone and/or PDL. Typically the radiolucency reduces in size over time but it does not completely disappear (Figure 8-18). Scar tissue may form following either treatment of an inflammatory condition with bone resorption (i.e., any form of apical periodontitis) or following surgical endodontic treatment.31 Periapical scars cannot be definitively diagnosed clinically; they can only be diagnosed histologically but surgery in order to biopsy a suspected periapical scar is not justified or indicated. Clinicians should recognize that this condition does occur and it should be part of the differential diagnosis of a persistent radiolucency following endodontic treatment. Typical symptoms—no symptoms; history of root canal treatment or a surgical endodontic procedure. Clinical findings—the tooth will have a restoration; the tooth has signs of root canal treatment (e.g., access cavity restoration); there are normal responses to percussion and palpation; no response to pulp sensibility tests. Radiographic findings—the tooth has a restoration; the periapical radiolucency is smaller than it was preoperatively and immediately postoperatively but it is persisting following root canal treatment or endodontic surgery; a root canal filling is evident; a root-end root canal filling may be evident if there is a history of previous endodontic surgery. Associated pulp/root canal conditions—usually considered as part of the differential diagnosis of a reduced but persistent radiolucency following root canal treatment or endodontic surgery; history of previous endodontic treatment with no signs of infection.