Overview :

The Plaque Formation Rate Index (PFRI) of Axelsson describes the accumulation of dental plaque at 24 hours after a professional dental clearing. This index can help identify patients at increased risk for caries, as described below.

NOTE: This is similar to the Calculus Surface Index, described earlier in this section.

Procedure:

(1) The teeth are cleaned by a professional dental hygienist.

(2) The patient does not brush or clean the teeth for the next 24 hours.

(3) 24 hours after the cleaning the teeth are examined for adherent plaque.

Surfaces examined on each tooth (6):

(1) mesiobuccally

(2) bucally

(3) distobuccally

(4) mesiolingually

(5) lingually

(6) distolingually

PFRI =

= (total number of surfaces showing plaque) / ((number of teeth examined) * (6 surfaces examined)) * 100%

Interpretation:

• minimum PFRI: 0%

• maximum PFRI: 100%

Axelsson P. Placknybildningsindex PFRI - Indikator for karies- och parodontitprevention, munhygien-frekvens och ytrelaterad munhygien. Tandlak tidn. 1989; 79: 7: 387-391.

Axelsson P. A four-point scale for selection of caries risk patients, based on salivary S. mutans levels and plaque formation rate index. IN: Johnson N (editor). Risk Markers for Oral Diseases. Volume 1: Dental Caries. Cambridge University Press. 1991.

Axelsson P. Diagnosis and Risk Prevention of Dental Caries, Volume 2. Quintessence Publishing Co, Inc. 2000. pages 7-9, 34-36.