Root strains associated with different obturation techniques

By Saw LH, Messer HH

Date: 01/1995
Journal: JOE


To evaluate the effects of various obturation techniques on root strain.


  • N=27 freshly extracted maxillary central incisors
  • exclusion: crazing/fractures, gross caries, immature apex
  • teeth sectioned 2mm coronal to CEJ and instrumented via step back to #40-45
  • utilized a strain gauge apparatus to measure strain with lateral condensation, obtura warm vertical compaction , and thermafil obturation; 9 teeth each group


  • a large proportion of strain in obtura/thermafil groups was due to thermal strain
  • mean load to cause vertical root fracture was 5-6x higher than the mean load used in obturation
  • upon inducing vertical root fracture, most fracture line ran buccal-lingually

Clinical Significance:

Thermafil may present the lower risk of contributing to vertical root fracture during obturation