Call for a review of diagnostic nomenclature and terminology used in Endodontics

Abstract

There can be no therapy without diagnosis. Indeed, diagnostics are at the core of the communication between healthcare provider and patient. In our field, it is essential for a patient to know whether their tooth can be saved, poses a health risk, and whether and for how long it will hurt after treatment. For the Endodontist, it is important to have the right diagnostic terms that can lead the way to the correct treatment, so that data from clinical studies can be related to each clinical situation. Diagnostic terms describing the pathological conditions that can affect the dental pulp and periapical tissues have traditionally been based on the concept that histology can reveal the true state of these tissues, even though histology by its nature merely depicts a situation at a specific point in time, and not the possible course of a disease that may follow. As a consequence, clinical signs and symptoms, the clinical diagnostic tests that can be performed, as well as radiographic imaging were inevitably related to histology. Unfortunately, the correlation between clinical and histological status was (and is) relatively poor, especially in pulpal diagnostics (Baume 1970, Dummer et al. 1980, Mejàre et al. 2012). With the dawn of evidence-based dentistry, it became even more obvious that it makes little sense to attempt to describe the status of tissues using histological features that in any particular case we know nothing about (Baume 1970). As a result, attempts were made to use what is known clinically when endeavouring to diagnose the state of pulp and periapical tissues, that led to a variety of disease classifications and the use of different terminology by authors, groups and organizations such as the World Health Organization (WHO, ICD-10) and the American Association of Endodontists (AAE) (Morse et al. 1977, Abbott & Yu 2007). An initiative to achieve a global consensus on the nomenclature and terminology used for pulp and periapical diseases was undertaken by the AAE some years ago (AAE 2009, Glickman 2009). Interestingly, the terms delineated by Morse et al. (1977) were included in the resultant classifications almost verbatim. Whilst this was a step forward, in the minds of the authors of this editorial, there are still problems with the terms developed by the AAE initiative and their translation to clinics and specific cases. First, the term ‘acute’ was avoided, probably because Morse and co-workers noted that this word had a double meaning; ‘clinically painful’ but also ‘showing an infiltrate with polymorphonuclear leucocytes (PMNs)’, that is a histological observation that could never be correlated to specific cases. As a consequence, the term acute was not incorporated within the AAE terminology. However, research has shown that spontaneous pain in a carious or cracked tooth sensible to cold is the main clinical sign to indicate an incipient (beginning) infection of the pulp (Ricucci et al. 2014). Moreover, at least on a research level, markers associated with PMNs can be identified without sacrificing the tooth (Rechenberg & Zehnder 2014). In the context of apical periodontitis, the term ‘acute’ was replaced by ‘symptomatic’, which unfortunately could mean anything from a tooth being sensitive to percussion to severely and spontaneously painful. As has been pointed out: ‘the terms symptomatic and asymptomatic have slowly crept into usage with little scientific basis for their applications or meanings’ (Gutmann et al. 2009). Secondly, atypical and chronic dental pain are clinically important (Pigg 2011, De Laat 2020), yet were not considered within the AAE or WHO classifications of pulpal/periapical conditions, rather they were listed separately (Benoliel et al. 2020). Treating teeth with a neuropathic element of pain the same as counterparts with purely infection-related conditions can lead to frustrating experiences for both the dentist and patient. Similar issues appear in the current terminology for periapical conditions, in which severe pain is not a core issue, even though it has been identified as such (Gutmann et al. 2009). Spontaneous pain from a pulpless tooth is the main reason why patients seek emergency dental care (Sindet-Pedersen et al. 1985, Rechenberg et al. 2016), and can lead to systemically relevant medical conditions (Nalliah et al. 2011). Moreover, pain before treatment is the main predictor for pain after treatment (Keskin et al. 2019). This is especially the case with teeth that have an element of atypical pain (Polycarpou et al. 2005). Last, but not least, new diagnostic tools and treatment concepts have evolved since the 1970s. Cone-beam computed tomography (CBCT) machines have become widely available, yet can lead to false-positive results when simply assessing the presence or absence of a periapical radiolucency, especially in root filled teeth (Kruse et al. 2019). Moreover, the terms ‘reversible’ and ‘irreversible’ pulpitis have become obsolete in the context of minimally invasive endodontics, because they relate to a perceived prognosis of direct pulp capping, not other vital treatments such as full pulp chamber pulpotomy (Wolters et al. 2017). In root canal-treated teeth, a lateral lesion on a periapical radiograph or CBCT scan together with a localized deep periodontal pocket is highly indicative of a vertical root fracture, which is the main reason for tooth loss in patients in good dental care (Axelsson et al. 2004). The concept of assessing the whole root rather than the root apex and periapical tissues was not considered in the AAE terminology either. The authors believe that there is an overwhelming need for a review of the existing nomenclature related to pulp and periapical diagnostics. As has been attempted with the more recent initiatives to create a global consensus (AAE and WHO), this new nomenclature and the specific terminology used for each disease state should be based on ad hoc clinical findings. However, pain should be considered as a core parameter. Furthermore, newer diagnostic tools and treatment modalities should be considered. Ambiguous terms such as reversible/irreversible and symptomatic/asymptomatic should be avoided. With the support of the European Society of Endodontology, the authors have planned an initiative to further explore the issues. The initiative aims to discuss the possibility of developing improved diagnostic nomenclature and terminology for pulpal and periapical conditions. However, it should be reiterated here and goes without question, that the thoughts expressed in this editorial are those of the authors, and that any new nomenclature that emerges must have broad support by experts in the field.

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