A comparative study of dentinal tubule penetration and the retreatability of EndoSequence BC Sealer HiFlow, iRoot SP, and AH Plus with different obturation techniques

Abstract

Objectives: This study aimed to evaluate dentinal tubule penetration and the retreatability of EndoSequence BC Sealer HiFlow (HiFlow), iRoot SP, and AH Plus when using the single-cone (SC) or continuous wave condensation (CWC) technique.

Materials and methods: Sixty-five single-rooted teeth were instrumented and randomly divided into 5 groups: group 1, AH Plus/CWC; group 2, iRoot SP/CWC; group 3, iRoot SP/SC; group 4, HiFlow/CWC; and group 5, HiFlow/SC. The ability to re-establish patency during endodontic retreatment was recorded, as was the time taken to reach the working length. Dentinal tubule penetration and remaining debris after retreatment were evaluated by confocal microscopy and scanning electron microscopy. Data were analyzed by Kruskal-Wallis test and Dunn's multiple comparisons test (α = 0.05).

Results: The HiFlow/CWC and iRoot SP/CWC groups required more time to reach the working length than groups that underwent the SC technique regardless of the sealer used (P < .05). The HiFlow/CWC group showed a significantly higher percentage of sealer penetration area than that of the iRoot SP/SC at 4 mm from the apex (P < .05) and penetrated deeper into dentinal tubules than iRoot SP/SC at both 8-mm and 12-mm levels (P < .05). Moreover, the HiFlow/CWC and HiFlow/SC groups demonstrated less remaining sealer along the canal wall than AH Plus/CWC group at 4-mm level (P < .05).

Conclusions: HiFlow/CWC technique showed better performance in dentinal tubule penetration than that of iRoot SP/SC. Both HiFlow and iRoot SP combined with CWC technique groups required more retreatment time than the other groups. Furthermore, using HiFlow with either the CWC or SC technique left less remaining sealer at 4-mm level than using AH Plus with the CWC technique during retreatment.

Clinical relevance: With favorable performance in dentinal tubule penetration and retreatability in endodontic retreatment, the combined use of EndoSequence BC Sealer HiFlow with the recommended continuous wave condensation technique may be a worthwhile choice in root canal treatment.

Keywords: BC Sealer HiFlow; Dentinal tubule penetration; Obturation technique; Retreatability; iRoot SP.

Fig. 1

The time taken to re-establish patency and to reach the WL (seconds) in five groups (*P < .05, **P < .01, and ***P < .001)

Fig. 2

Representative confocal laser scanning microscopy (CLSM) images of resected root surfaces at the 4-mm, 8-mm, and 12-mm levels from the apex after retreatment in five groups. (a) A scanned image of a resected root surface. (b) A confocal microscopy image overlapping with (a) shows sealers in the canal (yellow arrow) and sealer penetration into dentinal tubules, with the area of sealer mixed with rhodamine B shown in red. (c) A higher magnification image shows sealers remaining in the canal (yellow arrow). (d1–d4) AH Plus/CWC group. (e1–e4) iRoot SP/CWC group. (f1–f4) iRoot SP/SC group. (g1–g4) HiFlow/CWC group. (h1-h4) HiFlow/SC group

Fig. 3

Dentinal tubule penetration and remaining sealers in the canal wall in the five groups. (a–c) Box plots of the sealer penetration area (%) at the 4 mm, 8 mm, and 12 mm from the apex. (d–f) Box plots of the sealer penetration depth at the 4 mm, 8 mm, and 12 mm from the apex. (g–i) Box plots of the remaining sealers in canal wall (%) at the 4 mm, 8 mm, and 12 mm from the apex (*P < .05, **P < .01, and ***P < .001)

Fig. 4

Scanning electron microscopy (SEM) images of retreated root canals in the coronal, middle, and apical thirds with 3 different magnifications ([a1–o1] × 50, [a2–o2] × 800, [a3–o3] × 6000) in five groups. The red arrow shows the gutta-percha debris with a diameter of 20–30 μm (b3). The yellow arrow shows sealers debris with a diameter of 5–6 μm (k3)