Effect of Irrigation Activation Techniques and Gravity on Apical Extrusion in Immature Teeth: An In Vitro Study

Abstract

Background: This study investigated the effects of irrigation activation techniques (standard needle irrigation, passive ultrasonic irrigation, EndoActivator, and EDDY) and gravity (maxillary vs mandibular position) on apical irrigant extrusion in immature teeth.

Methods: Eight intact maxillary central incisors were prepared to simulate immature teeth with
1.1 mm apical diameters. Root canals were irrigated with 2.5% sodium hypochlorite, 17% Ethylenediaminetetraacetic acid, and distilled water. Each tooth was fixed into a hole prepared in the cap of an Eppendorf tube. To simulate the periodontal ligament, the Eppendorf tubes were filled with 1.5% agar agar, into which the teeth were placed. After the agar had solidified, the weight of the agar-filled Eppendorf tube without the tooth was measured using a microbalance. All 4 activation techniques were applied in both mandibular (vertical) and maxillary (45° inclined) positions. Following activation, the teeth were removed, and the Eppendorf tubes were reweighed. The difference between the final and initial weights was recorded as the amount of apical extrusion. Data were statistically analyzed using the Kruskal–Wallis and Mann–Whitney U-tests at a significance level of P < .05.

Results: No significant differences were found among the activation techniques or between the mandibular and maxillary positions (P > .05).

Conclusion: Although all techniques resulted in irrigant extrusion, neither the activation method nor the tooth position had a statistically significant effect. Clinicians should remain cautious when selecting and applying irrigation protocols in immature teeth to minimize the risk of extrusion.

Cite this article as: Sariyilmaz E, Sariyilmaz Ö. Effect of irrigation activation techniques and gravity on apical extrusion in immature teeth: an in vitro study. Essent Dent. 2026, 5, 0104, doi:10.5152/EssentDent.2026.25104.