Paper points revisited: risk of cellulose fibre shedding during canal length confirmation

To compare the degree of fibre shedding by six brands of endodontic paper point when used for the paper point technique (PPT) of working length confirmation.

An in vitro model simulating the clinical use of paper points in PPT was used to assess the degree of fibre shedding of six brands of size 20, .02 taper paper point. Whilst observing the artificial terminal foramen with polarized light microscopy, the number of fibres shed directly (point inserted 1 mm beyond the terminal foramen) and indirectly (point inserted to length then a gutta-percha point inserted) was assessed. The degree of direct fibre shedding as a function of brand was analysed with Fisher's exact test and multiple pairwise comparisons. Indirect fibre shedding was analysed with Kruskal-Wallis and Wilcoxon rank-sum tests.

All brands shed fibres both directly and indirectly, with a significant influence of brand on the proportion of fibres shed directly (P < 0.0306) and on the mean number of fibres shed indirectly (P < 0.0001). Post hoc analysis demonstrated a similar hierarchy of point integrity for both tests with Classic (UnoDent, Witham, UK) shedding significantly more than other brands and SS White (Gloucester, UK) and Antaeos^® (VDW, Munich, Germany) shedding the least.

All brands of paper point may shed cellulose fibres both directly and indirectly with a significant influence of brand on the degree of fibre shedding. Further work should be undertaken to develop biocompatible absorbent dental points.