The frequently used decayed, missing or filled tooth (DMFT) index provides accurate infor-mation to epidemiologists about the incidence of caries, tooth loss and tooth restorations. Unfortunately, the DMFT index provides no information on the pulpal and periapical status of teeth, limiting its applicability to endodontic treatment needs.

One index used to categorize the results of untreated caries—the PUFA index—measures

  • pulpal involvement (P)
  • ulceration caused by tooth fragments (U)
  • fistula formation (F)
  • abscess (A)

While this measure should be an effective screening device to determine which patients need to undergo further clinical and radiographic evaluation, its accuracy has not been established, nor has the PUFA index been used in adult populations. The second methodology evaluates a patient’s periapical status via the periapical index (PAI), which is based on a radiographic assessment, usually including panoramic radiographs. The PAI score has been validated, but radiographic assessment comes with its own drawbacks, including low sensitivity (true positive rate) compared with cone beam computed tomography (CBCT), radiation exposure and cost.

Teh et al from Universiti Kebangsaan Malaysia compared the diagnostic accuracy and reliability of the PUFA index and PAI. Their patient sample included 165 patients (4115 teeth) making their first visit to a university primary dental clinic. Consistent with clinic protocol of ordering panoramic radiographs for new patients presenting with multiple dental problems, panoramic radiographs were ordered for all patients. A clinical examination recorded a subjective assessment of the presenting complaint and pain level; an objective assessment including extraoral and intraoral examinations, pulpal test and periodontal examination, radiographic findings, etiology and prognosis; and a treatment plan.

Tests to achieve a definitive diagnosis included electronic pulp testing, cold test, percussion, palpation and probing depth.

Two independent, trained dentists, blinded to clinical diagnoses and PAI scores, examined the participants’ teeth, recording caries experience using the DMFT score, and the progression of caries in each tooth using the PUFA index. An endodontist, blinded to clinical diagnoses, DMFT scores and PUFA index, assessed the panoramic radiographs for periapical status. For the purpose of analyzing the data, PUFA index scores were classified as negative (0) or positive (>0); PAI scores were classified as negative (<3) or positive (≥3).

Both the PUFA index and the PAI showed extremely high specificity (true negative rate) for all 4115 teeth and for teeth recorded as decayed or filled. Sensitivity levels were lower, with the PUFA index outperforming the PAI. This relationship held when applied only to decayed teeth; however, both indices demonstrated a low level of sensitivity in filled teeth. Positive predictive value for pulpal disease was >90% for both the PUFA index and the PAI; only the PAI in filled teeth fell below 80% (Table 1). The PUFA index was significantly more accurate in diagnosing both pulpal and periapical disease than was the PAI.

Conclusion

Given its reliability and its greater accuracy than the PAI, the PUFA index, when used in conjunction with the DMFT index score, can be a helpful tool to screen for pulpal and periapical disease. Following this path could reduce the need for panoramic radiographs as a preliminary screening tool, reducing patients’ radiation exposure and costs incurred by the health care system.

Teh LA, Abdullah D, Liew AKC, Soo E. Evaluation of pulpal involvement, ulceration, fistula, and abscess index and periapical index in screening for endodontic disease: reliability and accuracy. J Endod 2020;46:748-755.