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Abstract

There are no universally accepted guidelines for general dental practitioners regarding when endodontic referral to a specialist service may be indicated. UK NHS specialist endodontic services do not have national standardised criteria for which patient cases will be accepted for specialist care, and it is therefore important that more complex cases can be identified by general practitioners and referred accordingly, decreasing the likelihood of avoidable iatrogenic errors occurring, which reduce treatment outcome.

There have been a number of indices developed to help ascertain the complexity of endodontic cases. Part 2 discusses tips for identifying endodontic case complexity and examines indices available to guide clinicians as to when referral to an endodontic specialist service may be warranted.

Introduction

Part 1 considered various patient-related, clinical and radiographic factors which impact on endodontic case difficulty. Part 2 discusses tools and guides available to further help clinicians assess case complexity.

Tools available to guide assessing endodontic case complexity

There are various published tools which help with endodontic clinical decision making and treatment planning, providing information on likely risks and their impact on treatment outcome.1 Using these can help focus patient discussions, enhancing understanding of complexities, risks and benefits, enabling informed consent and the decision as to whether to refer.2 Additionally, the use of tools and assessments, when recorded in patient records, may provide benefit medico-legally.

Endodontic diagnosis and treatment planning is based upon clinical and radiographic findings. Studies suggest general dental practitioners tend to underestimate the complexity of endodontic cases.3 Screening-type tools focus assessment and particularly consider relevant pre-operative radiographs factors. Their use is helpful because dentists' radiographic interpretation of relevant factors is improved by repetition and training.4,5

Regular use of structured assessment tools can enhance complexity identification, recommending the use of objective criteria for case assessment and treatment planning.6

There are a number of published indices to aid endodontic assessment:

  • Case Difficulty Assessment Form (AAECAF)7

  • Restorative Index of Treatment Need (RIOTN)8

  • Dutch Endodontic Treatment Index (DETI) leading to the Endodontic Treatment Classification (ETC)9

  • EndoApp10

  • The Dental Practicality Index.11

The diagnostic criteria for these tools are compared and summarised in Table 1.

Table 1 Summary comparison of endodontic complexity tools available for use
Full size table

Case Difficulty Assessment Form, American Association of Endodontics (2005)

The first version (1997) of The American Association of Endodontists guidelines for 'Evaluating Endodontic Treatment Risk Factors'12 was revised and re-released as the 'Case Difficulty Assessment Form' (AAECAF) in 2005.7

Originally devised in an educational setting to inform case suitability for students or trainees, the tool considers patient, diagnosis and treatment factors in deciding case difficulty.

Cases are scored and categorised as:

  • Minimal difficulty: Treatment is appropriate for a general practitioner

  • Moderate difficulty: May warrant referral, depending on skill and experience of clinician

  • High difficulty: Meriting consideration of a referral to a dentist with advanced skills in endodontics or specialist.

Although there is no evidence regarding its utilisation in primary care settings across the UK there is some uptake amongst GDPs in the USA. Research into the validity of this system is needed.13

Restorative Index of Treatment Need, Royal College of Surgeons of England (2001)

In the UK, a Restorative Index of Treatment Need (RIOTN) was developed by the Royal College of Surgeons of England8 using three complexity codes:

  1. 1.

    Treatment able to be performed by any dental graduate

  2. 2.

    Treatment able to be performed by any experienced dentist

  3. 3.

    Treatment able to be performed by any dentist with skills developed following specialist training.

It can be used for assessing the complexity of periodontal, endodontic and fixed and removable prosthodontic cases. Since the RIOTN was developed, there have been huge advances, in particular within microsurgical endodontics, and therefore, for some aspects of endodontics, this recommended scoring no longer reflects up-to-date evidence. It is also reportedly too simplistic, incomplete and with poor reproducibility for endodontic case difficulty assessment.14

Dutch Endodontic Treatment Index and Endodontic Treatment Classification, Ree, Tinnerman & Wesselink (2003)

Ree and colleagues (2003)9 surveyed GDPs in the Netherlands to produce a shortened screening tool for assessing risk and difficulty, named the Dutch Endodontic Treatment Index (DETI). The DETI is quicker and easier to use, potentially overcoming the proposed time-consuming shortcomings of AAECAF.13

DETI indicates the difficulty of a case and if found to be potentially difficult, a further index is used - the Endodontic Treatment Classification (ETC) to provide further information. ETC was well received by practitioners in the Netherlands with the majority finding it helpful in determining if referral is indicated. Endodontic assessments using DETI carried out by both GDPs and specialists also, reassuringly, show high correlations,13 which is encouraging considering lack of agreement between GDPs and endodontists about which teeth should be referred in other studies (with the exception of periradicular surgery cases).3

EndoApp, British Endodontic Society (2018)

The EndoApp is a structured web-based tool available for use online or download for endodontic evaluation and triage in primary and secondary care.10 It aims to overcome limitations of other tools, for example, the absence of quantification system with RIOTN and absence of some variables in AAECAF.10 The tool calculates a case difficulty score from a series of questions answered by the user and recommends which type of dental practitioner is best suited to managing the case. Small scale studies suggest the app is relatively quick to use and preferred by users to AAECAF.10

Dental Practicality Index, Dawood & Patel (2017)

A further recently published tool which takes into account the tooth's restorative state in relation to the patient's dentition, needs, expectation, medical and dental history is the Dental Practicality Index.11 This has three restorative categories and a 'context' category (ie general oral and patient factors) which are scored out of six where zero means that no treatment is required and six indicates that the tooth is not practical to restore and extraction should be considered. The scores between these extremes guide as to what level of endodontic skill/training is needed to treat the case. Scores can also be totalled; a score of 1-2 implying the case can be simply and predictably treated. An increasing score indicates more complex care needed, with a score ≥6 indicating the tooth is impractical to treat.

Since the DPI's inception a number of studies have attempted validation. The first15 retrospectively assessed the DPI from notes, study models and radiographs for 137 teeth and correlated this with the root canal treatment outcome. A moderate level of agreement between the two independent assessing endodontists was found, demonstrating the tool's subjectivity, however, several advantages of using the DPI were recognised: the DPI encourages the consideration of patient cases holistically and for root canal retreatments, using the DPI has good outcome prediction.16 Al-Nuaimi et al. (2020)16 used a similar retrospective method and two assessing endodontists. One hundred and forty-four teeth had DPI scores calculated and followed up to identify what happened to the tooth four years later. Teeth with a DPI score of >6 were found to have significantly less chance of survival than teeth with lower scores. This study concluded the DPI can predict which teeth, if endodontically retreated, are likely to be extracted. A recent BDJ Student article17 highlighted confusion regarding whether a tooth can be restored versus whether it is practical to restore it. This paper reported ease of use with the DPI, increasing clinician confidence in assessing tooth restorability.

Discussion

Endodontic treatment outcomes are affected by the complexity of the case, presence/creation of iatrogenic errors and skill level of the clinician carrying out treatment. Assessing case complexity prior to embarking on treatment will help guide appropriate referral, particularly when directed to NHS funded specialist services, and impact endodontic treatment outcome for patients.

Structured freely available tools are useful aids for assessing endodontic case complexity and can be retained as part of the dental records and guide as to when a referral might be considered. However, clinical reasoning and decision making is complex and multifactorial and the use of indices does not eliminate subjectivity, specifically with regard to the accuracy of radiographic understanding. Repeated use of case complexity guides increases the speed at which these can be completed9 and regular use may improve endodontic care quality through improved identification of possible problems/challenges before starting treatment; after treatment is started, iatrogenic errors are not always correctable. Using such guides may help structure clinical decisions, treatment planning and discussions, and aid evidence of this process for inclusion in dental records. Of the tools available, there is no consensus on which assessment tool is superior.

The European Society for Endodontology18 provides undergraduate endodontic guidelines stating that students should be competent at identifying treatment complexity and suggests the DETI or AAECAF may be helpful. Speculatively, the use of such structured assessment tools might favourably impact on the suboptimal quality of endodontic treatment identified as being carried out in the UK,19 which in turn may impact endodontic related medico-legal litigation. Consistency, understanding and agreement between GDPs and those receiving referrals is in the best interests of patients because identifying cases which may be better treated by a specialist clinician and referring appropriately improves treatment outcomes.1

Conclusion

There are several factors to consider when assessing the complexity of an endodontic case and clinicians must also take into account their own experience, skill and the patient's wishes. There are a number of assessment tools freely available to help guide assessing endodontic case complexity and whilst there is no current consensus on which assessment tool is superior, each provides some benefit in structuring and steering assessment, which can aid discussions, informed consent processes and when to refer.