Comparison of the effectiveness of the protaper system versus hand instrumentation in endodontic retreatment: a scanning electron microscopy study

Resumo

Several rotary systems have been evaluated for removal
of endodontic filling materials from the canal. Moreover, studies
focusing on the comparison of the effectiveness of rotary systems
versus hand instrumentation have yielded mixed results in terms of
the efficacy and amount of time required by each technique. Objective:
To compare the effectiveness of a nickel-titanium rotary system and
of hand instrumentation using stainless steel files and Gates-Glidden
burs in the removal of gutta-percha from root canals, as well as the
time required to complete the procedure by each method. Material
and methods: Forty single-rooted teeth were prepared and obturated
then divided in two groups, according to the method employed for
removal of the gutta-percha: ProTaper Universal rotary retreatment
system (rotary instrumentation) and stainless steel hand files with
Gates-Glidden burs (hand instrumentation). The time required to
remove gutta-percha by each method was recorded. Roots were
then sectioned lengthwise and the apical, middle, and coronal
thirds were analyzed by SEM under two magnifications: x400 and x1,000. Results: Rotary instrumentation promoted better cleansing
compared with hand instrumentation. The apical third was less clean
than the coronal and middle thirds (Kruskal-Wallis p < 0.05). Rotary
instrumentation was faster than hand instrumentation (Tukey p < 0.05).
Conclusion: Although none of the methods promoted complete
cleanliness of the canal walls, ProTaper Universal system showed
better results and was faster than hand instrumentation.