TABLE 5. Total number of patients, total number of teeth examined, frequency of AP, ET and frequency of teeth with ET associated with AP in different studies.

Author/Country	No. of Patients	No. of Teeth	Teeth w/AP (%)*	Teeth w/ET (%)*	Teeth w/ET/AP (%)**
This study (São Luís, Brazil)	200	5008	5.9	11	42.5
De Cleen et al. (Germany 1993)	184	4196	6.0	2.3	39.2
Buckley & Spangberg. (USA 1995)	208	5272	4.1	5.5	31.3
Sidaravicius et al. (Lithuania. 1999)	147	3892	7.2	15.0	39.4
De Moor et al. (Belgium 2000)	206	4617	6.6	6.8	40.4
Lupi-Peguirier et al. (France 2002)	344	7561	7.3	18.5	31.5
Dugas et al. (Canada 2003)	610	16148	2.3	3.1	45.5
Jiménez-Pizón et al. (Spain, 2004)	180	4453	4.2	2.1	64.5

^*percent values apply to the number of teeth examined

^**percent values apply to the number of endodontically treated teeth