Damage to Root Dentin During Retreatment Procedures

IntroductionThe aim of this study was to explore the influence of retreatment procedures on the appearance of defects on the root canal walls.MethodsTwo hundred mandibular premolars were divided into 4 groups. One group was left unprepared. The rest of the teeth were prepared with ProTaper files up to size F4 and filled with gutta-percha and AH26. One group was left filled and received no further treatments. The filling material was removed from the remaining teeth either with ProTaper retreatment files or with Hedström files. Roots were then sectioned and inspected under a microscope. Data were analyzed with the nominal regression test (α = 0.05).ResultsNo defects were observed in the unprepared group. Retreatment groups showed significantly more defects than the initial treatment group (P < .05).There was no difference between the appearance of defects after retreatment with Hedström files and ProTaper retreatment files. The remaining dentin thickness and level of the root did not significantly influence the appearance of defects.ConclusionsRetreatment procedures result in more defects than initial treatment. When assessing the outcomes of endodontic retreatment, the substantial damage to the root canal walls should be considered.