The flare-up index: a quantitative method to describe the phenomenon

Acute exacerbation of symptoms during the inter-appointment time interval of endodontic treatment is a well-known complication. The phenomenon is termed "flare-up" by most researchers and clinicians, although the exact definition of it differs from one author to another, making it difficult to compare the results of the studies. The suggested flare-up index may be the way to build a common language that will enable the dental community to measure and study more of this phenomenon.