Endodontic - Periodontal Lesions

Initially a detailed medical and dental history must be obtained from the patient. The patient's description of any signs or symptoms will usually lead the clinician to a provisional diagnosis. A full periodontal and endodontic examination must then be carried out to confirm the diagnosis and to identify or exclude any other diseases that may be present. 

The clinical examination should include inspection of the gingival and mucosal tissues, periodontal probing, palpation, mobility testing, percussion, pulp sensibility testing, occlusal assessment, biting tests and a radiographic examination. 

Periodontal probing is essential to identify and determine the depth of periodontal pockets and the degree of loss of attachment. Periodontal probing should be carried out for the entire dentition, not just the tooth involved. Any suppuration or bleeding on probing should be noted. 

Pulp testing should be carried out with both carbon dioxide (dry ice) and an electric pulp tester (heat testing is of limited diagnostic use unless the patient complains of heat sensitivity). Pulp tests used in conjunction with thorough clinical and radiographic examinations will give an indication of the clinical status of the pulp - that is, it is usually possible to determine whether there is a reversible pulpitis, irreversible pulpitis, necrotic pulp, or a pulpless, infected root canal system. 

Radiographs are an essential tool to the diagnosis of any endodontic or periodontal condition. Long-cone parallel radiographs should be taken in order to check for loss of crestal bone, presence of periapical or lateral radiolucencies, presence and depth of previous restorations, presence of previous root canal fillings, root fractures, or any other pathology or abnormalities. The radiographic examination findings should be recorded on the patient's record card. 

An adequate diagnosis should include a comment about the current status of both the endodontium and the periodontium. A tooth showing signs of both endodontic and periodontal diseases should be classified as having a "combined endodontic- periodontal lesion". The primary cause of this combined lesion may be obvious in some cases but not in others. Furthermore, in some cases, the lesions may be unrelated and this should be also be noted.

Treatment of combined endodontic-periodontal lesions should follow the same general principles for treatment of these entities as though they were separate lesions. That is, the periodontal disease should be treated by routine scaling, root planing, oral hygiene instructions and follow-up maintenance therapy, including surgery in some cases. Diseased pulp tissue or infected root canals should be treated by cleaning, shaping, medicating and filling of the root canal system.

Most teeth with combined endodontic-periodontal lesions will have an infected root canal system. Therefore the endodontic treatment should be carried out over multiple visits and in conjunction with the periodontal treatment. This will provide an opportunity for antibacterial intra-canal medicaments to be placed in order to predictably eliminate bacteria from the root canal system. 

Medicaments such as Ledermix paste and calcium hydroxide pastes have been recommended as routine intra-canal medicaments. Ledermix paste is an ideal medicament to be used as an initial dressing particularly if the patient presents with symptoms. However the antibacterial spectrum of Ledermix paste, against the most commonly found endodontic bacteria, has been reported to be somewhat limited whereas calcium hydroxide has been reported to be the most predictable antibacterial medicament for endodontic microbes. Therefore, calcium hydroxide should be used in the root canals of all infected teeth at some stage prior to the placement of the final root canal filling. Calcium hydroxide can either be used alone as a dressing or in combination with Ledermix paste (as a 50:50 mixture).

In teeth with previous restorations, the pulpal disease is very likely to be associated with, or caused by, recurrent caries or marginal microleakage and bacterial contamination of the pulp space - these problems must be eliminated if the endodontic treatment is to succeed. Therefore all previous restorations should be removed prior to commencement of the endodontic treatment and the tooth should then be assessed to determine whether it is suitable for further restoration if the endodontic and periodontal treatment is successful.

It is important to ensure that a tooth undergoing endodontic treatment is adequately temporised to ensure that the coronal cavity is sealed and that there are no periodontal consequences from the temporary restoration (such as overhangs, inadequate contour, food packing, inability to clean, etc). In some cases it may be necessary to place a stainless steel orthodontic band in order to stabilise the remaining tooth structure and/or retain the temporary restoration. The use of a reinforced glass ionomer material, such as Ketac Silver, is ideal in these situations in posterior teeth as it will provide an adequate long-term temporary restoration with minimal periodontal effects. A tooth-coloured glass ionomer or composite resin can be used in anterior teeth.

The use of multiple appointments for endodontic treatment is convenient for the treatment of combined endodontic-periodontal lesions as it allows time for the initial non-surgical periodontal treatment to be carried out before continuing with the final root canal filling. The response of the patient and the tissues can be determined and the prognosis can be reassessed before any further treatment is contemplated. The periodontal tissues should be monitored for at least three months prior to considering any further treatment. During this reassessment time, the root canals can be left with either calcium hydroxide or a calcium hydroxide/Ledermix mixture in the canals. 

The placement of medicaments in the root canals during this reassessment phase also allows adequate time for the medicament to diffuse through the radicular dentine in order to kill any remaining microbes - such medicaments require at least 3-4 weeks to achieve a predictable concentration within the peripheral (or outer) layers of the dentine. There may also be sore minor beneficial effects from the medicaments in helping to promote healing within the periodontal ligament, as dentine and cementum have been shown to be permeable to such medicaments.

If the initial phase of treatment does not result in adequate improvement of the periodontal tissues, then the tooth should be considered for further periodontal treatment, including surgery. Flap surgery may be chosen in order to gain adequate access to the entire root surface for root planing and debridement. Following this external cleaning of the root surface, the tissues should be monitored to determine the healing response. Again during this phase of treatment, the root canals should be left with an intra-canal dressing for a period of at least four to six weeks. Then, if the tissues show initial signs of healing, the root canal filling should be completed and an adequate coronal restoration placed. The case should then still be monitored, both periodontally (initially at three monthly intervals), and endodontically (initially after six months) in order to determine whether there has been periodontal and periapical healing.

The presence of a combined endodontic-periodontal lesion will always result in a compromised situation following treatment. Even with apparently successful treatment, the tooth will still be compromised as there is likely to be some gingival recession and loss of periodontal attachment and bone support. It is of utmost importance that the patient maintains good oral hygiene and obtains regular professional care for this region.