Periodontal disease is now thought by most researchers to be

caused by a mixed anaerobic infection, modulated by a complex

interplay with local and host factors.

Pulpal infection is a polymicrobial process & is of an anerobic nature.

As the infective process proceedes, the proportion of strict

anaerobic-to-facultative organisms & the total number of bacteria

increases.

An exception to this rule seems to be the microaerophilic A.

actinomycetemcomitans, which has been associated with aggressive

periodontitis (Newman & Socransky 1977).

Most of the species that have been found in infected root

canals can also be present in the periodontal pocket.

(Moore 1987, Sundqvist 1994)

Porphyromonas endodontalis seems to be very rare in oral

infections other than those of endodontic origin.

(VanWinkelhoff et al. 1988)

Overall, the root canal flora does not appear to be as

complex as the periodontal flora of adjacent pockets.

However, it is inherent problems in bacterial sampling of

periodontal pockets that strains from more shallow levels of

the site are harvested along with the strains at the front of

the lesion.

Necrosis of the pulp, however, can result in bone resorption Necrosis of the pulp, however, can result in bone resorption

and the production of radiolucency at the apex of the tooth, and the production of radiolucency at the apex of the tooth,

in the furcation or at points along the root.in the furcation or at points along the root.

The lesion that results may be:The lesion that results may be:

an acute apical lesion or abscess,

a more chronic peri-radicular lesion (cyst or

granuloma) or

a lesion associated with a lateral or accessory

canal.

The lesion may remain small, or it can expand sufficiently to The lesion may remain small, or it can expand sufficiently to

destroy a substantial amount of the attachment of the tooth destroy a substantial amount of the attachment of the tooth

and/or to communicate with a lesion of periodontitis.and/or to communicate with a lesion of periodontitis.

Different authors have created varying nomenclatures for

these pathologies, based on either etiological or clinical

criteria, or a combination of these factors.

Simon et al. (1972) separated the lesions of both

periodontal and pulpal tissues into the following groups:

Primary endodontic lesions with secondary periodontal involvement,

Primary periodontal lesions with secondary endodontic involvement,

and

True combined lesions.

Appropriate endodontic therapy is sufficient to

result in healing of the lesion.

Occasionally an abscess of pulpal origin, through

an apical or lateral canal, may establish drainage

through the periodontal ligament & erupt into the

furcation or the gingival sulcus.

(A)Preoperative radiograph showing large

periradicular radiolucency associated with

the distal root and furcal-lucency.

(B)Clinically, a deep narrow buccal

periodontal defect can be probed. Note

gingival swelling.

(C)One year following root canal therapy,

resolution of the periradicular bony

radiolucency is evident.

(D)Clinically, the buccal defect healed and

probing is normal.

Chronic periodontitis progresses apically

along the root surface.

In most cases, pulp tests indicate a

clinically normal pulpal reaction.

The prognosis depends upon the stage of

periodontal disease and the efficacy of

periodontal treatment.

The progress of periodontitis is slow.

The involvement of apical periodontium by the pulpal

lesion may obscure the symptoms of the periodontium.

Because the apical lesion tends to be the most painful

lesion, endodontic therapy is normally initiated first.

Endodontic therapy results in the resolution of the

endodontic lesion , but has little or no effect on the

periodontal pocket, an appropriate periodontal therapy is

required for a successful result.

Such lesions may present with the characteristic

of both diseases, which may complicate diagnosis

& treatment planning.

The extent to which the periodontal lesion

contributes to the loss of bone is a key

consideration in diagnosis & treatment planning

(A) Preoperative radiograph showing

periradicular radiolucencies. Pulp

sensitivity tests were negative.

(B) Immediate postoperative radiograph of

nonsurgical endodontic treatment.

(C) Six-month follow-up radiograph showing

no healing. Gutta-percha cone is

inserted in the buccal gingival sulcus.

(D) Clinical photograph showing treatment

of the root surfaces and removal of the

periradicular lesion.

(E) One-year follow-up radiograph

demonstrating healing.