Modifications to the PUFA Index: Are They Justified at This Stage?

We, the authors of the original publication presenting the PUFA/pufa index of clinical consequences of untreated dental caries [1], read with interest the publication by Baginska and Stokowska [2] entitled ‘Pulpal involvement-roots-sepsis index: a new method for describing the clinical consequences of untreated dental caries’ recently published in Medical Principles and Practice. In their publication, Baginska and Stokowska [2] used the original PUFA index and then made comparisons with their proposed modifications to the index: the pulpal involvement-roots-sepsis (PRS/prs) index.

First of all, we are pleased to observe the steady increase in papers recognizing the need to record the clinical consequences of untreated dental caries in order to supplement information collected through the more routinely used indices for dental caries. This trend is evidenced by about a dozen papers related to the use of the PUFA index, including national oral health surveys [3,4]. We noted the encouraging statement that the PUFA index was considered to be ‘a valuable measurement tool to record the clinical consequences of untreated dental caries’ in the context of the national oral health survey in Poland. We were therefore surprised that, in spite of this, further modifications to the original PUFA index were proposed [2].

Secondly, we wish to emphasize that the PUFA index is not an index of treatment need but rather an index to quantify the consequences of untreated caries. This differentiation is important since the modifications proposed by Baginska and Stokowska [2] aim to merge these two objectives into one index, which is not necessary or conceptually justified. The examples given relate to the scoring of ‘P/p’ (visible pulpal involvement of severely decayed teeth) and ‘U/u’ (ulceration caused by sharp edges of dislocated tooth fragments). With respect to these components, Baginska and Stokowska [2] consider that both codes do not distinguish adequately between cases where a tooth could be retained through endodontic and other treatments and those where extraction might be indicated. This observation is entirely correct but, as stated above, the PUFA index was never designed to function as a treatment needs index, nor was it ever proposed to be used in isolation without recourse to other routinely used indices for dental caries [1]. In this respect, we made explicit reference to the DMFT index and the current WHO standard methodology by stating that: ‘The index defines four different clinical stages of advanced caries providing “a face of the reality” to the prevailing and often ignored oral conditions. Presenting data based on the PUFA index will provide health planners with relevant information, which is complementary to the DMFT.’ [1]

Decisions about treatment need are inevitably linked to the resources and capacities of the health system setting. For instance, in many low- and middle-income countries the choices for interventions are limited and extraction of teeth with an open pulp with or without an abscess or fistula is often the only realistic way to relieve pain. PUFA can help to prioritize treatment by allowing the selection of patients with high PUFA scores when resources are scarce, but it specifically does not give indications as to what type of intervention should be applied.

Furthermore, the attempt of Baginska and Stokowska [2] to design an index that provides at the same time information on the consequences of untreated caries and information on treatment needs, i.e. the proposed pulpal involvement-roots-sepsis index as it appears in table 1 of their publication, seems to have failed in achieving its objective. For instance, the PRS index proposes only endodontic treatment for pulpal involvement (P/p) irrespective of whether primary or permanent teeth are involved, although in the accompanying text the authors acknowledged the very real financial (and other) barriers that exist in less affluent societies. While options concerning a different management for primary and permanent teeth are presented for the PRS index, in cases scoring sepsis (S/s) the same argument applies. It is for this reason that, under the section on treatment needs for dental caries in the WHO Oral Health Survey methodology, there is an acknowledgement that: ‘Countries vary greatly in the capacity of the dental profession to meet demands for oral health care and in professional attitudes and treatment technique.’ [5] The same section then goes on to say that: ‘examiners are encouraged to make use of their own clinical judgment when making decisions on what type of treatment would be appropriate, based on what would be the probable treatment for the average person in the community or country’. Rigid treatment need indicators, as presented in the PRS index, are therefore not appropriate.

Another consideration is that in an epidemiological survey it would be unlikely to only examine the clinical consequences of untreated dental caries and their associated treatment needs without also considering other aspects of dental caries. It is perhaps with this in mind that the FDI World Dental Federation, as a result of a complex expert consultation, has included the PUFA index in its new model for caries classification and management [6].

While we wholeheartedly welcome all suggestions for improving the relevance and appropriateness of the PUFA index, it should be borne in mind that the description of the PUFA index was only published 3 years ago, and for the moment the reports about its use in epidemiological surveys in different populations with different patterns of caries are still limited. Therefore, it may be premature at this stage to propose modifications to the original PUFA index. Such modifications can only lead to confusion and may result in eventual problems of data comparability. Moreover, they detract from the main intention of the index which is to demonstrate the unacceptably high levels of untreated caries, their severity and the associated impact on health and quality of life in order to facilitate appropriate action, which DMFT data alone has oftentimes failed to do in the past.

We are currently compiling studies that were performed with the PUFA index. With the growing and more reliable body of experience, we plan to convene an expert meeting in the near future to review the index and to determine its strengths and weaknesses in real life applications as a basis for possible modifications. In the meantime, researchers and public health personnel should attempt to make extensive use of the index, which has so far been proven to be easy to use and integrate into existing surveillance activities. A supportive tool kit is available to facilitate this, and active reporting of studies that use the PUFA index in the manner that was proposed in the original publication [1] would be very welcome.