Impact of Warm Vertical Compaction on the Sealing Ability of Calcium Silicate-Based Sealers: A Confocal Microscopic Evaluation

Abstract

The aim of this in vitro study was to evaluate the dentinal tubule penetration of two calcium silicate-based sealers used in warm vertical compaction (WVC) obturation technique in comparison with the single cone (SC) technique by confocal laser scanning microscopy (CLSM). The null hypothesis was that both obturation techniques produced similar sealer penetration depths at 1 and 5 mm from the apex. Forty-four mandibular single-rooted premolars were randomly divided into four equally experimental groups (n = 10) and two control groups (n = 2) according to the type of sealer (Bio-C Angelus, Londrína, PR, Brazil or HiFlow Brasseler, Savannah, GA, USA) with either SC or WVC. The sealers were mixed with a fluorescent dye Rhodamine B (0.1%) to enable the assessment under the CLSM. All the specimens were sectioned horizontally at 1 and 5 mm from the apex. The maximum penetration depth was calculated using the ImageJ Software (ImageJ, NIH). Data were analyzed by Mann-Whitney U and Kruskal-Wallis tests (p < 0.05). A significant difference was shown between the four groups at 1 mm (p = 0.0116), whereas similar results were observed at 5 mm (p = 0.20). WVC allowed better diffusion for both sealers at 1 mm (p = 0.01) and 5 mm (p = 0.034). The maximum penetration of the Bio-C and HiFlow sealers was more important at 5 mm with the two obturation techniques. Within the limitations of this study, WVC enhanced the penetration of calcium silicate-based sealers into the dentinal tubules in comparison with the SC technique at both levels.

Keywords: calcium silicate; confocal laser scanning microscopy; tubule penetration; warm vertical compaction.

Figure 1

Box plot representation of the sealers penetration depth at 1 mm (left) and 5 mm (right) depending on the obturation techniques.

Figure 2

Representative confocal microscopic images of each sealer’s depth penetration in the dentinal tubules at 1 mm from the apex: (A) HiFlow sealer with the single cone (SC) technique and (B) HiFlow sealer with warm vertical compaction (WVC). Moreover, at 5 mm from the apex: (C) HiFlow sealer with the SC and (D) HiFlow sealer with WVC.

Figure 3

Representative confocal microscopic images of each sealer’s depth penetration in the dentinal tubules at 1 mm from the apex: (E) Bio-C sealer with the SC technique and (F) Bio-C sealer with WVC. Moreover, at 5 mm from the apex: (G) Bio-C sealer with the SC and (H) Bio-C sealer with WVC.