In vitro Comparison of Root Canal Obturation Quality in Primary Molars using Lentulo spiral and Reverse Rotary Techniques with Zinc Oxide Eugenol and Endofloss: Microcomputed Tomography Analysis

Background Primary teeth are necessary for mastication, speech, and guiding the eruption of permanent teeth. Dental caries often requires pulpectomy treatment to preserve these teeth. The success of pulpectomy depends on root canal obturation quality. This study aimed to compare the filling quality of zinc oxide-eugenol (ZOE) and Endofloss using lentulo and reverse rotary techniques, assessed by micro-computed tomography. Methods An in vitro study was conducted on 32 extracted human primary mandibular second molars. Teeth were randomly divided into four groups (n = 8) based on obturation material (ZOE or Endofloss) and technique (lentulo spiral or reverse rotary file). After standard canal preparation, obturation was performed. Micro-computed tomography assessed the quality of obturation by measuring the percentage of void and filling volume. Statistical analysis was performed using ANOVA test (p < 0.05). Results The lowest total void percentage was observed in the (ZOE + Lentulo) group (22.61 ± 9.00), and the highest in the (Endofloss|+Lentulo) group (35.97 ± 5.90). ZOE obturation resulted in lower voids (24.09 ± 8.50) compared to Endofloss (30.70 ± 8.50). The reverse rotary technique showed non significant lower voids (25.50 ± 7.60) than Lentulo (29.29 ± 10.10) (p = 0.181). A significant interaction effect was observed between material and technique in term of total voids (p = 0.021). (ZOE + Lentulo) group showed the highest filling volume (76.50 ± 9.10), while(Endofloss + Lentulo) had the lowest (64.02 ± 5.90). ZOE yielded higher filling volume (75.47 ± 8.50) compared to Endofloss (69.22 ± 8.50), with a significant material effect (p = 0.034), but no significant effect of technique (p = 0.138). Conclusion ZOE + Lentulo technique provided the most root canal obturation quality, while Endofloss + Lentulo showed the least quality. The root canal filling quality was more influenced by the obturation material than the technique used.