Assessing the outcome of endodontic treatment

Assessing the outcome of endodontic treatment

 This month, in more detail, Dr Michael Sultan, clinical director of EndoCare, explains how to assess the outcome of endodontic treatment, whether a success or failure...  

When carefully planned and executed, by far, the majority of endodontic procedures will eventually result in a successful outcome. In elective procedures and hyperaemic teeth, the success rate is particularly high; climbing to an impressive 98 per cent. However, as soon as there is an associated lesion in an infected tooth, the success rates drop and the ultimate outcome may not be immediately obvious to the clinician. Healing may take months or even years, meaning that both clinician and endodontist have to spend time in communication post-treatment to carefully assess the final result. 

‘Success’ means different things to different people and may not be an absolute, black and white term. To some, it may just imply an absence or resolution of symptoms. This may be absence of pain and swelling, resolution of a sinus tract or even the patient’s ability to bite on a tooth without the need for analgesics or antibiotics. The literature relating to implants relates often to survival rates. In endodontics, success has many definitions; from the absolute-complete absence of symptoms and complete healing on a radiograph, down to healing with a much-reduced lesion, which may indicate scar tissue formation. Either way, we are often symptom-led and interpretation of radiographs may initially be difficult. 

Where symptoms remain, a decision has to be made as to whether this is due to slow healing with some residual bruising or an indication of failure. Patients often expect a complete absence of symptoms after an endodontic procedure, after all, “there’s no nerves in the tooth are there?” 

However, any dental procedure leads to inflammation in the surrounding tissues and, unfortunately, with regards to after-pain, we do seem to have a kind of ‘pain-in, pain-out’ relationship. 

Short-term after-pain is normal and handled with analgesics; this may be more prolonged in bruxists. Persistent pain may be indicative of slow healing, a mis-diagnosis or the early signs of failure. The specialist plays a vital role in this process as they are likely to possess the most suitable tools and knowledge to help decide whether or not healing is just slow and incomplete, or whether further treatment is required.

Traditionally, in terms of healing, dentists have been guided by the final and follow-up radiographs six months to one year after treatment. Often, however, the changes are very slow and subtle, and ideally there should be some standardisation of images, both in angulation and exposure. A digital radiograph with an appropriate sensor holder is usually the best way of comparing changes. The changes can be incredibly subtle with healing occurring from the periphery inwards and may not be immediately evident at the six-month mark.

With slow healing apparent, many factors should be considered, including the initial size of lesion, the patient’s age and their health. At six months after treatment, it is hoped that real signs of lesion reduction are evident. If this is not the case, the lesion should be reviewed at one year, and from then on at annual intervals. At each visit, a reduction in the size of the lesion should be expected with faster healing following surgical procedures. 

However, surgical procedures may not appear to fully heal with complete bony infill as there may be an element of scar tissue formation. The research suggests that this can take up to four years for complete healing. If, after this time, healing has not occurred or symptoms have recurred at any point, then healing is unlikely.

In the absence of symptoms, we are guided by the radiograph. It is, however, impossible to look at an apparent lesion around a tooth in a new patient and judge whether this is success or failure. Only by seeing earlier radiographs, and actually making a comparison, can we judge whether things are going in the right direction and healing or the lesion is persistent or worsening.

In treating teeth with lesions or treatment difficulties, it is imperative to arrange a follow-up appointment. This is in order to advise both the patient in regards to further issues, as well as the referring practitioner, regarding the timing of definitive restorations. In general terms, it is best to restore vital teeth immediately to reduce the chance of an influx of bacteria by coronal leakage. 

However, in teeth with large lesions or uncertain prognoses, these should be sealed as well as possible, and perhaps have a laboratory-made temporary crown as cuspal protection until there are good signs of healing. At this stage, the definitive coronal restoration can be made.

If after the follow-up the patient has noticed a worsening of their symptoms or the lesion has increased, real decisions have to be made as to how the situation can be improved. The prime offender is predominately bacteria. There may be persistent infection due to inadequate cleaning, odd anatomy or an inaccessible canal due to a blockage or a separated instrument. 

Perhaps re-infection has occurred along a fracture line or a new infection via a faulty coronal restoration. More uncommonly, a persistent cyst or even something more sinister may be the source of apparent failure. Further information may be provided by a conebeam CT scanner. This may reveal information about missed canals or unusual anatomy and increase the prognosis of re-treatment. If the area is inaccessible or other pathology is suspected, surgery may well be indicated. 

 

   

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