Discussion.
In this study, 48.9% of teeth were filled within 2 mm of the apex. This result is higher than in reports by Swedish researchers (Eckerbom et al.1989), who evaluated intraoral periapical films in patients in the age group ranging from 20 to over 60 years. In that study,40.2% of treated canals were filled 0-2 mm short of the radiographic apex. Comparable outcomes were observed by Eriksen et al. (1988) who reported that 41% of root fillings were adequate. Odesjoet al. (1990), when examining an adult Swedish population, reported that 30%of treated canals were adequately filled. A considerably lower percentage of properly filled canals (14%) was reported by Weiger et al. (1997) in a German urban population (Stuttgart).
The relationship between the disease and the apical level of filling (Table 5) demonstrates that in the teeth without periapical radiolucencies, more than half (59.2%) were adequately filled.
There is a relationship between chronic apical periodontitis and inadequate root canal treatment (Bergstrom et al. 1987, Eriksen 1991, Petersson et al.1991, Krupinski et al.1995). The findings of this study confirm these previous observations. Amongst the teeth with periapical radiolucencies, 17.4%were adequately filled, the remaining 82.6% were inadequately filled (Table 5).
Seltzer (1988) reported that the diagnostic value of a single dental radiograph should not be overestimated when the root canal is properly filled. Thus, it is possible that periapical radiolucencies in the process of healing were recorded as evidence of pathosis in this study.
Table 5 describes that amongst root-filled teeth,75.5% did not have chronic periapical disease whereas in 24.5%, pathosis was observed. Other reports from Polish studies (Krupinski et al. 1995, Boltacz-Rzepkowska 1998) have described a higher percentage of endodontically treated teeth with periapical pathosis. For example, Krupinski et al. (1995) reported that 31.6% of root-filled teeth had radiographic signs of periapical pathosis. Boltacz- Rzepkowska (1998) reported that 37.2% of root- filled teeth had evidence of chronic apical periodontitis. Other European investigators have reported higher percentage of root-filled teeth with periapical pathosis compared to the results of this study. De Cleen et al. (1993) reported that 39.2% of root-filled teeth had periapical lesions in an adult Dutch population, whilst Eriksen & Bjertness (1991) reported that 44% of teeth had lesions in a Norwegian population.
The percentage of root canal-treated teeth with periapical pathosis in this study is markedly lower than it has been reported by other authors. Separation of the group of teeth treated with pulpotomy in which periapical radiolucencies were frequently observed must have had an influence on our results.
In this study, an unfavorable outcome of treatment in the group of teeth treated with the amputation method was observed. Periapical pathosis was evident in 67.1% of these teeth. However, Sidaravicius et al. (1999), whilst evaluating the quality of endodontic treatment in an adult population from Vilnius in Lithuania, considered that 56% of pulpotomies were successful on the basis of the intraoral radiographs using the Periapical Index - PAI (Erstavik et al.1986).
Some studies report a high success rate of root canal treatment within the range of 90-96% (Erstavik et al. 1987, Sjogren et al.1990, Pawlicka et al.1994, Jaoui et al. 1995). However, these results are associated with procedures carried out in dental schools or by endodontists. In general dental practice, the percentage of the positive results is much lower and ranges from 61to 77% (Eckerbomet al.1989, De Cleen et al.1993, Boltacz-Rzepkowska 1998). These observations confirm the results of our study. High quality root canal treatment was more common in patients treated at the Institute of Dentistry in Lodz (64.0% of adequately filled root canals) than in private practice (53.3%). The worst results were found after treatment within the National Dental Health Care System in dental outpatients’ departments (71.4% of inadequately filled root canals) and in dental offices of schools (63.2%).

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