The relationship of endodontic-periodontic lesions.

By Simon JH1, Glick DH, Frank A

Date: 04/2014
Journal: JOE

•Five types of lesion formation that are interrelated based on their possible etiology, diagnosis and prognosis of treatment

1.Primary endo:


-Minimal discomfort, but usually no pain.
No response to Vitality tests.

Sinus tract, normal pocket depth or narrow pocket. Drainage from gingival sulcus area and/or swelling in buccal attached gingiva. 

No plaque or calculus detected.

*Periodontic only in that they pass through periodontal ligament area.


-Different levels of bone loss depending on the avenue of fistulation.

1-  Necrotic pulp may cause fistulous tract from the apex through the periodontium along the mesial or distal root surface, to exit at the cervical line. This appears as RL along entire root length (greyish bony matrix may be visible).

2-  Into bifurcation area creates appearance of periodontal involvement. Similar RG appearance may result from continual pulpal irritation through accessory canal opens in bifurcation area. 

3-  Fistulation through accessory canal some distance from the apex on mesial or distal resembles an infra-bony pocket.

4-  If fistulation occurs on the buccal or lingual aspect and is superimposed over the tooth root, RL may not appear on RG.

Diagnostically, one should be suspicious of pulpally induced lesion when crestal bone level on the mesial and distal appears relatively normal and only the bifurcation area is radiolucent. 

2. Primary endo. Secondary perio:

– If primary endo remains untreated, it may become secondarily involved with periodontal breakdown.

– Plaque forms at gingival margin of the sinus tract and leads to plaque

– induced periodontitis in the area. 

– Probe or explorer encounters plaque or calculus. 

– Requires both endo and perio therapy. 

– Prognosis depends on Perio therapy, assuming endo procedures are adequate. 

– With endodontic therapy alone, only part of the lesion may heal which indicates presence of secondary perio involvement.  –

– In general, healing of the endo induced areas may be anticipated.

  -May also occur as a result of root perforation.

-Symptoms may be acute, with periodontal abscess formation 

-associated with pain, swelling, pus or exudate, pocket formation, and tooth mobility. 

3- Primary Periodontic Lesions

– Progression of periodontitis apically along the root surface, until reaching the apical region.

– Occlusal trauma may or may not be superimposed in these lesions.

– The pulp is vital. Pulp responds vitally to endodontic testing procedures.

– Radiographic appearance of periodontal disease.

– Diagnosis based on periodontic test procedures.

– Probing reveals plaque and calculus accumulation for varying lengths along root surface. 

– Pockets are wider.

– In full covered teeth, cavity testing to confirm the vitality of the tooth and indicate that It is a perio lesion.

–  Prognosis depends wholly upon efficacy of periodontal therapy. 

4. Primary perio secondary endo:

– As perio lesions progress toward the apex, lateral or accessory canals may be exposed to the oral environment which lead to pulp necrosis

– Pulpal necrosis can result from periodontal procedures where the blood supply, through an accessory canal or apex is severed by curette (scaling and root planning or surgical flap) can also lead to secondary endo involvement.

– These primary perio lesions with secondary endo may be RG indistinguishable from primary endo with secondary perio.

– Prognosis depends on perio therapy once endo therapy solved.

–  Periodontal treatment alone not sufficient. 

5- “True” Combined Lesions

Where endo induced PA lesion exists on tooth that is also perio involved.  – The radiographic infra-bony defect is created when these two entities meet and merge somewhere along the root surface. –

1-  Clinical and RG picture is indistinguishable from the other two lesions that are secondarily involved. 

2-  RG appearance of combined endo-perio disease may be similar to that of a vertically fractured tooth.
→If fistula is present, it may be necessary to lay a flap to help determine the exact etiology. 

3-  Fracture that penetrated the pulp with resultant necrosis also can be labeled a “true” combined lesion.

– Periapical healing anticipated following successful endo therapy.

–  The periodontic aspects then may or may not respond to perio tx, depending on severity of involvement.