The medical conditions which require special precautions prior to root canal treatment have already been listed. There are, however, other conditions both general and local, which may contra-indicate root canal treatment.
General Inadequate access
A patient with restricted opening or a small mouth may not allow sufficient access for root canal treatment. A rough guide is that it must be possible to place two fingers between the mandibular and maxillary incisor teeth so that there is good visual access to the areas to be treated. An assessment for posterior endodontic surgery may be made by retracting the cheek with a finger. If the operation site can be seen directly with ease, then the access is sufficient.
Poor oral hygiene
As a general rule root canal treatment should not be carried out unless the patient is able to maintain his/her mouth in a healthy state, or can be taught and motivated to do so. Exceptions may be patients who are medically or physically compromised, but any treatment afforded should always be in the best long-term interests of the patient.
Patient s general medical condition
The patient’s physical or mental condition due to, for example, a chronic debilitating disease or old age, may preclude endodontic treatment. Similarly, the patient at high risk to infective endocarditis, for example one who has had a previous attack, may not be considered suitable for complex endodontic therapy.
Patient s attitude
Unless the patient is sufficiently well motivated, a simpler form of treatment is advised.
Local Tooth not restorable
Unless the patient is sufficiently well motivated, a simpler form of treatment is advised.
Local Tooth not restorable
It must be possible, following root canal treatment, to restore the tooth to health and function (Fig. 11). The finishing line of the restoration must be supracrestal and preferably supragingival.
An assessment of possible restorative problems should always be made before root canal treatment is prescribed.
Insufficient periodontal support
Provided the tooth is functional and the attachment apparatus healthy, or can be made so, root canal treatment may be carried out.
Non-strategic tooth
Extraction should be considered rather than root canal treatment for unopposed and nonfunctional teeth.
Root fractures
Incomplete fractures of the root have a poor prognosis if the fracture line communicates with the oral cavity as it becomes infected. For this reason, vertical fractures will often require extraction of the tooth while horizontal root fractures have a more favourable prognosis (Fig. 12).