The clinical relevance and correlation between the initial straight length to the first curvature in human second...

The aim of this study was to evaluate the straight lengths of the root canal of human second maxillary premolars using standardized radiological techniques in vitro. The distances were examined starting from the cemento-enamel junction (CEJ) to the appearance of a curvature. In particular recommendations which may facilitate decision making with regard to the length of post systems after successful endodontic treatment should be available. Extracted human second maxillary premolars (n = 210) were used; teeth with root caries, artificial crowns, extensive fillings or with previous endodontic treatment were excluded from this investigation. The teeth were fixed in a specially developed device with standardized and reproducible distances and digital radiographs using the parallel technique were made. A descriptive statistical analysis and the calculation of the cumulative frequencies were made. The values for the distance starting from the CEJ to a first curvature were as follows: a) For right second premolars: median value=10.3 mm (min.: 5 mm; max.: 15.8 mm) and mean value= 10.4 SD+/- 2.6 mm; b) left second premolars: median value =10.2 mm (min.: 5 mm; max.: 17 mm) and mean value =10.3 mm SD +/-2.2 mm. Based on our data, high number of second maxillary premolars showed a curvature (30.4%) 9 mm apically from the CEJ. These findings should be taken into consideration for endodontic treatments and post insertions.