Coronal leakage following three obturation techniques

Aim To compare coronal bacterial and India ink leakage in three different obturation techniques with the smear layer having been removed. Methodology Seventy extracted single-rooted teeth were instrumented to an apical preparation size 7 Profile Series 29 (Tulsa Dental Products, Tulsa, OK, USA). The smear layer was removed and 20 teeth were randomly obturated with lateral compaction, 20 teeth with vertical compaction, and 20 teeth with Thermafil (Tulsa Dental Products, Tulsa OK. USA). Ten teeth were used for positive (five teeth) and negative (five teeth) controls. Teeth were stored for 90 days in 100% humidity, then subjected coronally to Proteus vulgaris for 21 days to assess bacterial leakage. Following bacterial challenge, India ink was placed coronally for a further 21 days, then scored according to depth of dye leakage. Results Vertical compaction leaked significantly less than lateral compaction during bacterial challenge. However, when dye was used there were no significant differences. Conclusions Bacterial leakage and dye leakage demonstrated considerable variability. The use of a dye following bacterial testing may highlight the failure of experimental devices and vertical root fractures, thus avoiding false positive results found with bacterial testing alone.