Antibacterial Effects of Antimicrobials Used in Regenerative Endodontics against Biofilm Bacteria Obtained from Mature and Immature Teeth with Necrotic Pulps.

INTRODUCTION: We investigated the direct and residual antibacterial effects of intracanal antimicrobials against bacterial biofilms obtained from infected mature and immature teeth with necrotic pulps. METHODS: Sterile dentin slabs (n = 100) were inoculated with bacterial biofilms obtained from root canals of an immature or a mature tooth with pulpal necrosis and incubated anaerobically for 3 weeks (n = 50 per biofilm). Dentin infected with each type of biofilm received 1 week of treatment with 1 or 5 mg/mL double antibiotic paste (DAP) in methylcellulose hydrogels, calcium hydroxide, or placebo paste or received no treatment (n = 10). The pastes were removed, and biofilm disruption assays were performed. Additional dentin slabs (n = 100) were pretreated with the same treatments (n = 20). The pastes were rinsed off, and the samples were immersed in phosphate-buffered saline for 1 week. Thereafter, samples from the treatment groups were infected with bacterial biofilm from both clinical sources mentioned earlier (n = 10 per biofilm) and incubated anaerobically for 3 weeks before conducting biofilm disruption assays. Uninfected dentin slabs were used for both antibacterial experiments as negative control groups (n = 20). RESULTS: All antimicrobials showed significant direct antibacterial effects regardless of the biofilm source. Dentin pretreated with 5 mg/mL DAP provided significantly higher residual antibacterial effects in comparison with all other groups regardless of the source of biofilm. Dentin pretreated with calcium hydroxide did not show any residual antibacterial effects. CONCLUSIONS: Tested antimicrobials showed significant direct antibacterial effects. Only 5 mg/mL DAP exhibited significant residual antibacterial effects against bacterial biofilms from an infected root canal of an immature tooth.

Comparison of cone-beam computed tomography and periapical radiography in predicting treatment decision for periapical lesions: a clinical study.

Objectives. To compare the ability of endodontists to determine the size of apical pathological lesions and select the most appropriate choice of treatment based on lesions' projected image characteristics using 2 D and 3 D images. Study Design. Twenty-four subjects were selected. Radiographic examination of symptomatic study teeth with an intraoral periapical radiograph revealed periapical lesions equal to or greater than 3 mm in the greatest diameter. Cone-beam Computed tomography (CBCT) images were made of the involved teeth after the intraoral periapical radiograph confirmed the size of lesion to be equal to greater than 3 mm. Six observers (endodontists) viewed both the periapical and CBCT images. Upon viewing each of the images from the two imaging modalities, observers (1) measured lesion size and (2) made decisions on treatment based on each radiograph. Chi-square test was used to look for differences in the choice of treatment among observers. Results. No significant difference was noted in the treatment plan selected by observers using the two modalities (χ(2)(3) = .036, P > 0.05). Conclusion. Lesion size and choice of treatment of periapical lesions based on CBCT radiographs do not change significantly from those made on the basis of 2 D radiographs.

Cytotoxicity comparison of three current direct pulp-capping agents with a new bioceramic root repair putty.

INTRODUCTION: The purpose of this in vitro study was to compare the cytotoxicity of white mineral trioxide aggregate cement (AMTA, MTA-Angelus), Brasseler Endosequence Root Repair Putty (ERRM), Dycal, and Ultra-blend Plus (UBP) by using human dermal fibroblasts and a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. METHODS: Cultured adult human dermal fibroblasts were exposed to multiple concentrations of material elutes. The test material samples were immersed and incubated in the culture medium for 2, 5, or 8 days at 37°C. The cytotoxic effects were recorded by using an MTT-based colorimetric assay. Positive and negative controls were used. The results were statistically examined by one-way analysis of variance and Tukey post tests. RESULTS: The cell viability of cultures exposed to all dilutions of AMTA, ERRM, and UBP was statistically similar to the negative control at 2 and 5 days. Only the Dycal-exposed specimens exhibited a statistically significant increase in cytotoxicity at the 2 initial evaluation periods. After exposure to the 8-day elutes, the respective percentage of cell survivability was 91% (Brasseler), 88% (MTA-Angelus), 76% (Ultra-blend Plus), and 37% (Dycal). CONCLUSIONS: From the data in this in vitro study, AMTA, ERRM, and UBP had statistically similar adult human dermal fibroblast cytotoxicity levels. Relative to the negative control, only Dycal was shown to have a statistically significant cytotoxic effect to adult human dermal fibroblasts at all tested intervals.

Cytotoxicity comparison of mineral trioxide aggregates and EndoSequence bioceramic root repair materials.

INTRODUCTION: The purpose of this bench top evidence level 5 in vitro study was to compare the cytotoxic effect of 2 brands of white mineral trioxide aggregate cement (ProRoot MTA and MTA-Angelus), Brasseler EndoSequence Root Repair Material, and Brasseler EndoSequence Root Repair Putty by using human dermal fibroblasts. METHODS: The cells were cultured in recommended culture conditions and exposed to the tested materials. The cytotoxic effects were recorded at an observation period of 24 hours by using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)-based colorimetric assay. Results were analyzed by using one-way analysis of variance with significance of p < .05. RESULTS: All materials tested demonstrated cell viability ≥ 91.8%. Overall, there was no statistically significant difference in cell viability of ProRoot MTA, MTA-Angelus, and Brasseler EndoSequence Root Repair Material. However, there was a statistically significant difference negatively associated with the cell viability of human dermal fibroblasts in association with the Brasseler EndoSequence Root Repair Putty. CONCLUSIONS: The Brasseler EndoSequence Root Repair Materials were shown to have similar cytotoxicity levels to those of ProRoot MTA and MTA-Angelus.