Overextension of root canal filling material beyond the apex is a recognized procedural complication that may necessitate retreatment. This comparative in vitro study aimed to evaluate the time required to remove experimentally overextended gutta-percha from single‑canal mandibular premolars using three retreatment methods: manual Hedstrom files (H‑files), the ProTaper Universal Retreatment (PTUR) rotary system, and an XP-endo Retreatment approach combining XP‑endo Shaper and XP‑endo Finisher R (referred to here as XPER).
The primary study objective was procedural time efficiency for complete removal of the overextended filling material. The trial design and measured endpoint focus on time as an operational outcome relevant to clinical retreatment workflow.
Thirty‑six extracted permanent mandibular premolars with a single canal were selected and prepared to a standard total length of 19 mm. To create an overextension model, canals were prepared 3 mm beyond the apical foramen up to the F2 file of the ProTaper Gold system.
Overextended obturation was performed using a size 25/08 gutta‑percha cone together with an epoxy resin–based sealer (AH‑Plus) via the cold lateral condensation technique. After obturation, specimens were stored for 7 days to ensure complete setting of the sealer before any retreatment attempts. The model therefore replicates an overfilled canal that has been allowed to set prior to retreatment.
Specimens were randomly allocated into three equal groups (n = 12 per group) according to the gutta‑percha removal method:
Each group used the designated instrument sequence and technique to remove the overextended filling material. The study compared these established manual and contemporary retreatment rotary options under standardized in vitro conditions.
The primary outcome recorded for each specimen was the time taken to achieve complete removal of the overextended gutta‑percha. Time measurements were collected during the retreatment procedures and subsequently analyzed for statistical differences between groups.
Statistical methods were applied to determine whether observed differences in procedural time reached statistical significance. The source reports comparisons and P values with a significance threshold (P < .05) for inferential conclusions about group differences.
The XPER technique (XP‑endo Shaper + XP‑endo Finisher R) demonstrated a statistically significant reduction in the time required to remove the overextended gutta‑percha compared with both the manual H‑files and the PTUR rotary system (P < .05).
In rank order of procedural speed, the groups performed as follows: XPER (shortest time) > PTUR (intermediate time) > H‑files (longest time). The source reports that the difference between XPER and the other two methods reached statistical significance, indicating superior time efficiency for the XP‑endo Retreatment protocol in this experimental setting.
No additional quantitative data (for example, mean times, standard deviations, or effect sizes) were reported in the abstract available from the source; detailed numeric results are not reproduced here because they were not reported in the provided source text.
Authors concluded that the XPER technique was significantly faster than both manual Hedstrom files and the ProTaper Universal Retreatment system for removing experimentally overextended gutta‑percha, demonstrating superior procedural time efficiency in this in vitro model.
The study received ethical clearance from the Research Ethics Committee of the Faculty of Dentistry, Alexandria University (protocol cited in source). Donated extracted teeth were provided with informed consent, the work complied with the Declaration of Helsinki, and the authors declared no competing interests.
Indexed MeSH terms and substances for the article include mandibular premolars, overextended obturation, retreatment, root canal filling materials, gutta‑percha, epoxy resin–based root canal sealer (AH‑Plus), and in vitro techniques. The publication is categorized as a comparative study in BMC Oral Health.
Clinicians and researchers should note this study’s in vitro design and that reported findings address procedural time under standardized laboratory conditions. Details on numeric time values and additional procedural metrics were not available in the provided source abstract and would require consulting the full text for further quantitative analysis.