Two medicaments (formalin guaiacol: FG and formalin cresol: FC) have been investigated clinically as root canal antiseptics by ordinal criteria.
Three hundred and eighty-seven patients (pulpitis; 131 cases, periodontitis; 256 cases) participated in this study. Their endodontic treatments were carried out by routine endodontic technique, and clinical evaluation was completed at every visit according to several clinical symptoms which were shown on a protocol card (Table 2) .
The results can be summarized as follows:
1) FG and FC were effective for acute pulpitis and acute periodontitis. But in asymptomatic cases (234 cases), it was difficult to evaluate clinically the antiseptic effect on both medicaments.
2) No side effects in respect of FG and FC appeared in any of the cases.
3) It was suggested that there is a difficulty in evaluating the antiseptic effect of root canal treatment by clinical symptoms alone, therefore it is recommended to introduce some additional evaluation such as culture test.