Getting the language right

art two of specialist endodontist Julie Kilgariff’s update on diagnostic terminology looks at periradicular diagnoses

25 May, 2015 / clinical
 Julie Kilgariff  

The first part of this article described how to arrive at a pulpal diagnosis of a clinically healthy or diseased pulp. Part two will describe the up-to-date terminologies for periradicular health and disease and the clinical findings usually associated with each of these diagnoses.

How to identify clinically normal periradicular tissues

Clinically ‘normal’ periradicular tissues are those which have no swellings or sinuses visible or palpable, the tissues are not tender to palpation and the tooth is not tender to percussion.Radiographically, the periodontal ligament space is uniform around the root and the lamina dura intact.

Teeth with normal and reversibly inflamed pulps would be expected to exhibit ‘normal’ periradicular tissues.

Conventional radiographs can be insufficiently sensitive to show the initial periradicular changes

Some teeth with symptoms of symptomatic irreversible pulpitis can be difficult to localise because in the early stages, the periradicular tissues are often not yet affected. At this point, the tooth will not be tender to percussion or palpation and no swelling or sinuses will be present. Conventional radiographs are frequently insufficiently sensitive to show the initial periradicular changes which can hamper localisation and diagnosis of the source of the pain. Thus, teeth diagnosed with symptomatic and asymptomatic irreversible pulpitis will often appear to have normal periradicular tissues radiographically until pulpal necrosis ensues.

Previously initiated and previously treated teeth may also exhibit normal periradicular tissues if treatment hasbeen successful.

What are the clinical signs and symptoms of symptomatic periradicular periodontitis?

Teeth exhibiting signs and symptoms of symptomatic periradicular periodontitis are most likely to have a pulpal diagnosis of pulpal necrosis; previously initiated endodontics or previous endodontic treatment. Table 1 reviews the range of clinical findings which can be associated with this diagnosis.

When the pulpal diagnosis associated is ‘pulpal necrosis’, the periradicular changes are caused by microbes gaining access to the root canal system mainly through cracks, caries, dentinal tubules and micro-leakage. This results in an inflammatory reaction in the periradicular tissues because of the egress of toxins through the apical foramina. The source of these toxins is the polymicrobial infection within the root canal system.

Where the pulpal diagnosis associated is ‘previously treated’ (i.e. a failed previous non-surgical or surgical endodontic treatment), the cause of the periradicular disease in the majority of cases is persistent or new (secondary) microbial infection of the root canal system. For example, where a dental/rubber dam is not used for isolation of the tooth during a root canal treatment, it is extremely likely that microbes will persist within the root canal system throughout and following treatment.

In a case where a previously successful root canal treatment (i.e. no clinical signs or symptoms of pathosis and no periradicular radiolucency is seen associated with the tooth radiographically) manifests with clinical and/or radiographic signs and/or symptoms of treatment failure, the most likely explanation is that either previously surviving microbes have now flourished within the root canal system to a pathogenic level or that new microbes have gained access, e.g. because of the loss of the coronal seal 1.

In the minority of cases where a failed root canal treatment is identified, the reason may also be attributable to a foreign body reaction, extra-radicular infection or the presence of a true cyst.

Each of these can also present with the signs and symptoms of symptomatic periradicular periodontitis. Figures 1a and 1b illustrate a case of a radicular cyst.

What are the clinical signs and symptoms of an asymptomatic periradicular periodontitis?

This particular periradicular diagnosis is often an incidental finding, for example when taking a routine periapical radiograph prior to replacing a failing crown. This finding potentially poses a management dilemma for the patient and clinician alike.

Should we embark on root canal treatment or re-treatment on a tooth which has presented the patient with no problems and risk iatrogenic errors occurring and the monetary costs associated with the endodontic procedures undertaken2? Table 2 outlines the range of clinical findings usually associated with this diagnosis.

It has long been recognised in Scotland that a large proportion of the population who have had extensive coronal restorations on vital teeth or teeth with previous endodontic treatment, will have asymptomatic periradicular periodontitis present (identified by radiographic periradicular radiolucencies) 345.

This is a disappointing finding and raises questions as to the understanding and management of endodontic pathosis by clinicians, as well as to the techniques used to monitor the endodontic status of teeth.

The literature is relatively sparse in ascertaining the risk of monitoring such asymptomatic lesions rather than embarking on active treatment (root canal re-treatment, surgical endodontic procedures or tooth extraction).

It has, however, been reported that those teeth which already have a root canal treatment in situ and are maintained with a good quality coronal seal, are at little risk of either becoming symptomatic or demonstrating an increase in size of the periradicular radiolucency on radiographs6.

What are the clinical signs and symptoms of a chronic periradicular abscess?

The clinical scenarios frequently encountered with this periradicular diagnosis are outlined in Table 3.

When a chronic periradicular abscess is present, drainage can occur through the periodontal ligament space (Figs 2a and b), forming a narrow, deep periodontal pocket over time or it may drain through the alveolar bone forming a sinus/fistula.

When present, a sinus can fluctuate between discharging and non-discharging. Once identified as present, two factors should be noted: First, the location of the sinus as those located close to the gingival margin can be associated with vertical root fractures7. Testori et al., identified coronally located sinuses in 42 per cent of vertically root fractured teeth8.

Sinus tracts closer to the apical area are more commonly associated with periradicular pathosis. Secondly, the sinus should be palpated to see if it is discharging. If so, a gutta percha cone can be threaded into the sinus tract until it stops and a periapical radiograph taken of the cone in situ, thus tracking the source of the infection.

Sinuses can occur both intra-orally or extra-orally and can be some distance from the source of the infection and so where possible it is advisable to radiograph with a gutta percha cone in situ to localise the source with some accuracy.

When a sinus is identified as associated with a previously endodontically treated tooth, this is a clear indication that further intervention is required (tooth extraction or further endodontic treatment).

Table 1 – The Clinical Signs and Symptoms of Symptomatic Periradicular Periodontitis

This is inflammation and destruction of the periradicular periodontium
that is of pulpal origin

Associated pulpal diagnosis:
Pulpal necrosis; previously initiated or previously treated
Patient history
Pain – often on biting or touching tooth
Generally well localised
+/- relieved temporarily by cold
+/- previous trauma to tooth
+/- previous endodontic treatment to tooth
Clinical findings+/- caries &/or deep restoration
+/- previous root canal treatment
+/- mobile & extruded from socket
+/- discoloured tooth
Pulp testsNegative
NB false positives can occur from multi-rooted teeth
Periradicular tests:
• PercussionPositive
• Palpation
Positive or negative
• Swelling / sinus
Radiographic findingsWidened periodontal ligament space
Loss of lamina dura
Periradicular radiolucency

Table 2 – The Clinical Signs and Symptoms of an Asymptomatic Periradicular Periodontitis
This is inflammation and destruction of the periradicular periodontium that is of pulpal origin

Associated pulpal diagnosis:
Pulpal necrosis; previously initiated or previously treate
Patient historyNil of note
May be previous history of incidence of acute pain which
spontaneously resolved
+/- low grade discomfort
+/- acute exacerbations
Clinical findingsCaries, heavily restored tooth, previous carious pulp exposure etc
+/- discoloured tooth
Pulp testsNegative
NB false positives can occur from multi-rooted teeth
Periradicular tests:
• PercussionNegative
• PalpationNegative
• Swelling / sinusNone
Radiographic findingsWidened PDL space
Loss of lamina dura
Periradicular radiolucency

Table 3 – The Clinical Signs and Symptoms of a Chronic Periradicular Abscess
An inflammatory reaction to pulpal infection and necrosis characterised by gradual onset, little or no discomfort and an intermittent discharge of pus through an associated sinus tract.

Associated pulpal diagnoses:
Pulpal necrosis, previously initiated or previously treated

Patient history & clinical findingsLittle or no discomfort
+/- intermittent discharge of pus through an associated sinus tract
Patient might report a ‘bad taste’
If sinus heals/stops discharging, patient may report pain
No systematic involvement
Pulp testsNegative
Periradicular tests:
• PercussionMay feel ‘different’ but not acutely painful
• PalpationMay be slightly tender, but not acutely painful
• Swelling / sinusSinus present
Radiographic findingsPeriradicular radiolucency seen

What are the clinical signs and symptoms of an acute periradicular abscess?

Table 4 summarises the probable clinical findings associated with a periradicular diagnosis of acute periradicular abscess.

When diagnosing the source of an acute abscess it is important to discern between a possible periodontal abscess and a dental abscess. Both periodontal abscesses and blocked periodontal pockets can present a similar clinical picture to that of a dental abscess (e.g. the tooth and associated tissues can exhibit tenderness to percussion and palpation, swelling and the patient reporting pain).

To aid diagnosis, thorough clinical examination in conjunction with a number of tests (cold, hot, electrical pulp tests, test cavities and periapical radiographs) can be useful to deduce which teeth are vital (and therefore likely to have a periodontal abscess) and those which are non-vital (with a pulpal necrosis and likely dental abscess). It is of note however that multi-rooted teeth can present with false positive and negatives to pulpal tests and hence the need for several pulpal investigations and/or tests to increase reliability of the findings.

Figures 3, 4a and b illustrate two cases where pulp testing was invaluable in coming to a diagnosis and for treatment planning. The case in Figure 3 is that of a deep non-healing periodontal pocket in the 13, 12 region. All sensibility tests undertaken revealed 13 and 12 to respond normally and both 13 and 12 were diagnosed with a clinically normal pulp. Excisional biopsy was undertaken and histological processing revealed a lateral periodontal cyst to have been present.

In Figure 4a, a radiograph of tooth 12 is shown. Clinically, 12 had deep periodontal pockets and mobility. If the diagnosis was made based on the radiographic findings alone, tooth 12 may have been thought to have a pulpal necrosis and evidence of an asymptomatic periradicular periodontitis. However, this tooth responded normally to all sensibility tests and was diagnosed with a clinically normal pulp. The history sheds light on this unusual appearance. Figure 4b shows an earlier radiograph which was taken prior to the recent surgical removal of an impacted canine. Figures 5a and b show an example of a tooth diagnosed as ‘previously treated and acute periradicular abscess’ and its management.


What are the clinical signs and symptoms of a condensing osteitis?

Condensing osteitis is a relatively commonly occurring radio-opaque lesion in the jaws, seen in 4-7 per cent of the population. Its cause reported as due to pulpal degeneration/inflammation or necrosis which results in the replacement of cancellous bone by dense, compact bone in some individuals9. It is frequently found as an incidental discovery associated with an often asymptomatic tooth (Fig 6) and hence it can be identified as associated with asymptomatic irreversible pulpitis cases amongst other diagnoses.

As illustrated in Figures 6 and 7, its identification is usually radiographically because clinical signs and symptoms (described in Table 5) rarely show that periradicular changes are present. Condensing osteitis indicates pulpal inflammation is present and thus sensibility testing of the tooth in question is warranted. Where the pulp is found to be necrotic, root canal treatment or extraction is the treatment of choice.

Alternatively, in cases where the tooth is still vital, a plan of watchful waiting or root canal treatment can be considered.

If further invasive treatment is intended, such as a crown preparation, it may be advisable to consider an elective root canal treatment as evidence of a stressed, irreversibly inflamed pulp is present (Fig 7). Condensing osteitis will usually resolve following appropriate treatment (removal of the irreversibly inflamed or necrotic pulp through root canal treatment or tooth extraction).

Table 4 – The Clinical Signs and Symptoms of an Acute Periradicular Abscess

Microbes and their toxic by-products have egressed into periradicular tissues to establish an extradicular infection and evoke purulent inflammation.

Associated pulpal diagnosis:
Pulpal necrosis; Previously initiated or Previously treated
Patient history & clinical findingsPain +/- systemic manifestation (Fever, malaise,
lymphadenopathy, headache, nausea)
+/- mobility, tooth may be extruded
+/- trismus
+/- dysphagia
Pulp testsNegative
NB multi-rooted teeth may give a false positive
This test can be useful to discern between a periodontal abscess and a periradicular abscess
Periradicular tests:
• PercussionPositive
• PalpationPositive
• Swelling / sinusSwelling either in vestibule or fascial space
Radiographic findingsReaction to infection can be very fast. The involved tooth may or may not show radiographic evidence of a widened periodontal ligament space. In time, a periradicular radiolucency seen

Table 5 – The Clinical Signs and Symptoms of Condensing Osteitis
A diffuse radiopaque lesion representing a localised bony reaction to a low-grade inflammatory stimulus

Associated pulpal diagnosis:
Symptomatic or asymptomatic irreversible pulpitis; Pulpal necrosis or Previously initiated treatment
Patient history & clinical findingsNo discomfort although may have a history of
pain episodes from tooth
Often tooth is heavily restored
Unlikely to have had previous root canal treatment on tooth, although can be history of pulp cap and pulpotomy
Usually an incidental finding
Pulp testsNegative or positive
Periradicular tests:
• PercussionNegative
• PalpationNegative
• Swelling / sinusNone
Radiographic findingsA diffuse radiopaque lesion usually at the apex of a tooth


Suggested up-to-date diagnostic terminologies for pulpal and periradicular health and disease are conveniently based on describing the clinical, rather than histological findings. This aims to simplify the diagnosis and aid communication between colleagues and patients alike. It is recommended that both a pulpal and periradicular diagnosis be made for every endodontically-involved tooth and that this be recorded in the dental notes.

Clinicians should be mindful of the dynamic nature of endodontic disease and use a range of investigations and special tests to try to ascertain as accurate information as possible on the status of the pulp and periradicular tissues to allow precise diagnosis and appropriate treatment planning. Following any treatment to the pulp and periradicular tissues (such as pulp cap, pulpotomy, root canal treatment, re-treatment and surgery), reviewing the pulpal and periradicular status on an annual basis, or more frequently, is recommended.

It is noteworthy that, in cases of odontogenic pain (where the treatment plan involves a root canal treatment or re-treatment), following pulpal extirpation and biomechanical preparation of all root canals to full working length (under a rubber dam and using sodium hypochlorite irrigation in the apical third), but for a transient inflammatory reaction to the endodontic procedure itself, the odontogenic pain experienced should decrease rapidly. Where this does not occur, the original diagnosis should be reviewed.

A small number of patients who have had good quality endodontic management will continue to experience post-treatment pain. Nixdorf and colleagues10 reported ongoing persistent pain in 5.3 per cent of cases following endodontic treatment, concluding that around 3.4 per cent of these cases were in fact due to pain of non-odontogenic origin which had been misdiagnosed as odontogenic pain at the outset. Accurate diagnosis of pulpal and periradicular tissues will help avoid inappropriate treatment.


1. Abbot PV. Diagnosis and management planning for root-filled teeth with persisting or new apical pathosis. Endodontic Topics. 2011; 19: 1–21
2. Wesselink PR. The incidental discovery of apical periodontitis. Endodontic Topics. 2014; 30: 23-8
3. Saunders WP, Saunders EM. Prevalence of periradicular periodontitis associated with crowned teeth in an adult Scottish subpopulation. British Dental Journal 1998;
185: 137–40.
4. Saunders WP, Saunders EM, Sadiq J, Cruickshank E. Technical standard of root canal treatment in an adult Scottish sub-population. British Dental Journal. 1997; 182:382–6.
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6. Van Nieuwenhuysen JP1, Aouar M, D’Hoore W Retreatment or radiographic monitoring in endodontics. International Endodontic Journal. 1994; 27(2): 75-81.
7. Tsesis I, Rosen E, Tamse A, Taschieri S, Kfir A. Diagnosis of Vertical Root Fractures in Endodontically Treated Teeth Based on Clinical and Radiographic Indices: A Systematic Review. Journal of Endodontics. 2010; 36: 1455–1458
8. Testori T, Badino M, Castagnola M. Vertical root fractures in endodontically treated teeth: a clinical survey of 36 cases. Journal of Endodontics 1993; 19: 87–91.
9. T.L. Green TL, Walton RE, Clark JM, Maixner D. Histologic Examination of Condensing Osteitis in Cadaver Specimens. Journal of Endodontics. 2013; 39(8): 977-9.
10. Nixdorf DR, Moana-Filho EJ, Law AS, McGuire LA, Hodges JS, John MT. Frequency of non-odontogenic pain after endodontic therapy: a systematic review and meta-analysis. Journal of Endodontics. 2010; 36(9): 1494-8

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