Root Canal Treatment Pre-op Assessment – The Basics

Root canal treatment pre-op assessment is crucial to provide patients with more information and the likelihood of success. This post is a very quick overview of factors during the assessment that must be considered prior to commencing root canal treatment.

Root canal treatment is often the only way a patients’ tooth can be saved. This is often the treatment of choice when bacteria has progressed into or past the pulp, sometimes causing pain and inflammation and leading to irreversible pulpitis (if symptomatic will cause lingering pain on a thermal test) or periapical periodontitis (if symptomatic usually tender to percussion). Root canal treatment may be justified if there are two or more signs of pulp non-vitality, including:

• Pain
• Periapical periodontitis
• Discolouration, suggestive of necrosis
• Sinus or swelling
• Negative sensibility test

Aims of Root Canal Treatment include:
>> Removal of microbes and pulp debris, including use of irrigation
>> Create sufficient space for irrigation
>> Avoid iatrogenic damage to the canal system and tooth
>> Preserve the integrity and location of apical canal anatomy
>> Facilitate a root canal filling
>> Avoid further irritation and infection of periapical tissues
>> Preserve sound root dentine and allow for the long-term function of a tooth

Root Canal Treatment Pre-op Assessment

A Pre-op radiograph is a fantastic way of assessing the tooth and surrounding anatomy. This is important and can tell us more about:

• Tooth and root morphology
• The number of canals
• Length, direction and degree of curvature
• Branching and lateral canals
• The size and position of the pulp chamber and apex in relation to the external surface
• The Estimated Working Length (EWL) – this is between a coronal reference point and the apex
• Any bone loss or resorption in the area
• An idea of where the bacteria has spread

Pre-op radiographs are usually taken using periapicals so that the whole tooth, root, crown, and bone are visible. Sometimes the periapical must be taken at an angle, especially for multirooted teeth, to avoid superimposition of anatomical features.

However, cone-beam computed tomography (CBCT) can be used when a conventional periapical is not enough, where there is a possibility of root resorption or a complex root canal system, for example, dens invaginatus. This is very rare in general practice, and usually requires a referral to a specialist or hospital. CBCT can sometimes have a reduced field of view compared to periapicals but is high resolution and can help to detect missed anatomy.

Clinically, it is important to assess the tooth by itself, as part of the arch, periodontally and restoratively. If these are favourable, then root canal treatment may serve a better prognosis. A tooth may be of strategic value to function or aesthetics.

Some problems may occur if secondary caries undermines the restorative structure, if access and vision are impaired or if the patient is unable to open their mouth enough for treatment – especially as it is essential to protect the patient during root canal treatment,  with a rubber dam in place. It may also be difficult to orientate the morphology if the tooth is currently crowned. These will make the tooth more unfavourable to treat and will rely on the skill and experience of the clinician. Sometimes, fractures or non-negotiable canals may be encountered, reducing the prognosis of the tooth.

It is therefore important to use appropriate radiographical and clinical assessments prior to beginning endodontic treatment to collect as much information as possible.

Root Canal Treatment Pre-op Assessment on Radiographs and Clinically

Some things to look out for on a periapical radiograph, or clinically that may make root canal treatment difficult, or more unfavourable include:

• A sinus present, perhaps an endo-perio lesion
• Deep pocketing around the tooth
• Mobility
• Pain and swelling
• A non-functional tooth- i.e., the patient avoids eating on it/doesn’t bite on it
• A large periapical area
• Abnormal anatomy
• Curved roots- as they may increase the likelihood of perforation
• Dentine thickness – if this is thin, this increases risk of fracture
• Length of root
• Caries or secondary caries
• Root resorption

The criteria for case selection should be unique for each case, weighing up prognosis and favourability, and incorporating patient factors. It should include:

• Good periodontal health and alveolar support
• Adequate remaining tooth structure
• Favourable occlusal plane and tooth position
• Favourable medical history
• Ability to anaesthetise the tooth
• Ability for the patient to open their mouth to allow sufficient access
• Manageable or no gag reflex
• Straight forward signs and symptoms
• Good radiograph available without superimposition of anatomical features
• Effective isolation with rubber dam
• Good recognition of morphology

These factors should provide you with a guide of what to assess prior to commencing root canal treatment.

Useful Links & Recommended Reading

• Cohen S, Burns RC, Walton R, Torabenijad M. Pathways of the Pulp (1). Learning. 1998;30(10).
• Walton, R.E. and Torabinejad, M., 1996. Principles and practice of endodontics. 2-nd ed. Phiadelphia: WB Saunders Co, pp.214-215.
• Endodontics: Principles and Practice
• ExamineDental
• Single Best Answer Questions for Dentistry