Semester

Summer

Date of Graduation

2026

Document Type

Thesis

Degree Type

MS

College

School of Dentistry

Department

Not Listed

Committee Chair

Jerry Bouquot

Committee Member

Samuel Dorn

Committee Member

Mark Byron

Abstract

Abstract

Evaluation of the Antimicrobial Activity of Four Endodontic Sealers Against

Streptococcus mutans and Enterococcus faecalis Using the Agar Diffusion Test

Dakota A. Bailey, D.D.S.

Introduction: The antimicrobial activity of root canal sealers may contribute to the elimination of residual microorganisms that persist following chemomechanical preparation. Limited research has directly compared contemporary bioceramic sealers with traditional sealers against both Streptococcus mutans and Enterococcus faecalis. NeoSEALER EzFlo is a recently introduced bioceramic sealer with limited published antimicrobial data. The purpose of this study was to evaluate the antimicrobial activity of EndoSequence BC HiFlow, NeoSEALER EzFlo, AH Plus Jet, and Kerr Pulp Canal Sealer against Streptococcus mutans and Enterococcus faecalis using the agar diffusion test at 24, 48, and 72 hours.

Methods: This in vitro study evaluated fifteen agar plates per bacterial species. Enterococcus faecalis (ATCC 29212) was cultured on Remel 5% Sheep Blood Agar and Streptococcus mutans (ATCC 25175) was cultured on Moltox Mitis Salivarius Agar. Bacterial suspensions were standardized to 0.5 McFarland and serially diluted to 10⁶ CFU/mL. Wells of 3 mm diameter were created with a sterile biopsy punch and freshly mixed sealers were placed immediately. Zones of inhibition were measured in millimeters at 24, 48, and 72 hours by a single examiner using digital calipers. Statistical analysis was performed using two-way and three-way repeated measures ANOVA with Greenhouse-Geisser correction and Bonferroni post-hoc comparisons in SPSS.

Results: Against Enterococcus faecalis, EndoSequence BC HiFlow demonstrated the greatest antimicrobial activity, followed by Kerr Pulp Canal Sealer, NeoSEALER EzFlo, and AH Plus Jet. All pairwise comparisons were statistically significant (p < .001). Zone of inhibition increased significantly from 24 to 72 hours for all sealers. Against Streptococcus mutans, AH Plus Jet demonstrated the largest zone of inhibition at all time intervals, a finding attributed to a probable interaction between the selective components of mitis salivarius agar and the tested sealers. NeoSEALER EzFlo and EndoSequence BC HiFlow did not differ significantly against Streptococcus mutans (p = .136). The three-way ANOVA demonstrated a highly significant Sealer × Bacteria interaction (F(1.814, 25.396) = 888.575, p < .001, partial η² = .984).

Conclusions: Within the limitations of this in vitro study, all four sealers demonstrated measurable antimicrobial activity against both organisms. EndoSequence BC HiFlow demonstrated superior antimicrobial activity against Enterococcus faecalis. The relative antimicrobial effectiveness of the four sealers differed significantly depending on the bacterial species tested. This study represents one of the first investigations of the antimicrobial activity of NeoSEALER EzFlo against endodontic pathogens.

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