Correction to: Influence of foraminal enlargement on the healing of periapical lesions in rat molars.

Figures 2 and 3 in the published version of this article contained a mistake. CCP and DCP should have been FEG and NFEG. Correct figures are presented here.

Influence of foraminal enlargement on the healing of periapical lesions in rat molars.

OBJECTIVES: The aim of this study was to evaluate the influence of foraminal enlargement on the healing of induced apical periodontitis in a rat model. MATERIAL AND METHODS: Periapical lesions were bilaterally induced in mandibular first molars of 24 Wistar rats, through root canals exposure to the oral environment during 3 weeks. Endodontic treatment was performed in the mesial canal of right molars, which were separated into two experimental groups (n = 12/group). The foraminal enlargement group (FEG) received instrumentation in the entire root canal length, including the cemental canal, while in the non-foraminal enlargement group (NFEG), instrumentation was carried out 1 mm short of the apical foramen. Root canals were filled with gutta-percha and AH Plus sealer, in the same visit, 1 mm short of the apical foramen in both experimental groups. Left molars were not treated and served as a baseline control group. The animals were killed after 4 weeks, and their hemi-mandibles were prepared for radiographic and histological analysis. Data were analyzed by Student's t test and ANOVA. RESULTS: Only FEG presented lower areas of periapical radiolucency compared to the control (p < .05). Both FEG and NFEG allowed decreased inflammation intensity (p < .0001 and p < .01) and higher scores of cementum neoformation when compared to non-treated samples (p < .0001). FEG was more effective than NFEG in promoting biological seal, i.e., apical closure with cementum (p < .01). FEG, but not NFEG, showed lower scores of root resorption than the control. CONCLUSIONS: Foraminal enlargement during root canal preparation improved periapical healing in rat molars. CLINICAL SIGNIFICANCE: Foraminal enlargement has been suggested to improve disinfection at the apical portion of root canals. This procedure may favor the healing of chronic periapical lesions.

Dendritic cells and their relation to apical peridontitis.

The purpose of this manuscript was to re-discuss apical periodontitis, apical biofilm, and its possible relationship with dendritic cells (DC). DCs are potent regulators of the immune system and their function is divided into three categories that involve the presentation of antigens: the presentation of antigens and activation of T cells; a not well established category suggested that DCs induce and maintain immunological tolerance; and the maintenance of the immune memory in conjunction with B cells. DCs in periapical inflammatory lesions are composed of at least two subpopulations that can be distinguished on the basis of ultrastructure and phenotype. These populations might differ in lineage, state of maturation, differentiation, activation, and/or function. The authors hereby analyzed the root apexes of teeth under SEM, after performing apicoectomy due to the failure of conventional endodontic treatment. Microbial biofilm with multispecies and areas of resorption with the presence of Howship lacunae, and images suggestive of denditric cells could be observed. The presence of DCs in periapical lesion could be an indication of the severity of the lesion, with a constant presence of antigen in the periradicular region.

Effectiveness of lateral and secondary canal filling with different endodontic sealers and obturation techniques

Objective: this study aimed to compare the performance of the new endodontic sealer GuttaFlow 2 (GF2) with two conventional sealers - AH Plus (AHP) and EndoFill (EF) - for filling artificial lateral and secondary canals with the following two obturation techniques: cold lateral condensation (CLC) and Tagger's hybrid technique (THT). Materials and method: sixty single-rooted human teeth were selected and subjected to root canal preparation. Next, specimens were subjected to a diaphanization method. During this process, artificial lateral and secondary canals were produced at 2, 5, 9, and 12 mm from the root apex. The specimens were randomly assigned into six groups (n = 10) according to endodontic sealer (GF2, AHP, or EF) and obturation technique (CLC or THT). The filling of lateral and secondary canals was analyzed by stereomicroscopy. The images were obtained and transferred to the ImageJ software. The mean filling percentages were calculated considering total linear measurements of artificial canals and their filled portions. Data were compared by two-way Anova, followed by Bonferroni Post-Hoc Test, at 5% significance level. Results: all materials showed the ability to penetrate into artificial lateral and secondary canals. There was no significant difference (P>0.05) between sealers and obturation techniques. Only GF2 showed a significantly improved flow into lateral canals when compared to secondary canals (P<0.05). Conclusion: GF2 shows proper flow for filling ramifications of the main root canal, but presents no advantage over conventional zinc oxide-eugenol-based or epoxy resin-based filling materials.

In vitro antibacterial activity of a silicone-based endodontic sealer and two conventional sealers.

The aim of this study was to evaluate whether the modification in the silver component is capable of providing GuttaFlow 2 with antibacterial activity against Enterococcus faecalis compared with epoxy resin-based (AH Plus) and zinc oxide and eugenol-based (Endofill) sealers. The antibacterial activity was evaluated using a reference strain of E. faecalis (ATCC 29212). Freshly mixed sealers were subjected to the agar diffusion test (ADT), while the direct contact test (DCT) was performed after materials setting. ADT results were obtained through measurements, in millimeters, of the inhibition zones promoted by the materials, using a digital caliper. In DCT, values of CFU/mL promoted by the three sealers were compared in three experimental periods (1 min, 1 h, and 24 h). The data were analyzed using Kruskal-Wallis and Dunn post-hoc tests (p < 0.05). In both ADT and DCT, GuttaFlow 2 presented no effect against E. faecalis, while Endofill and AH Plus showed similar inhibition zones. Endofill was the only material capable of reducing bacterial growth in DCT. In conclusion, modifications in the silver particle of GuttaFlow 2 did not result in a sealer with antibacterial effect against E. faecalis.

In vitro antibacterial activity of a silicone-based endodontic sealer and two conventional sealers

Abstract The aim of this study was to evaluate whether the modification in the silver component is capable of providing GuttaFlow 2 with antibacterial activity against Enterococcus faecalis compared with epoxy resin-based (AH Plus) and zinc oxide and eugenol-based (Endofill) sealers. The antibacterial activity was evaluated using a reference strain of E. faecalis (ATCC 29212). Freshly mixed sealers were subjected to the agar diffusion test (ADT), while the direct contact test (DCT) was performed after materials setting. ADT results were obtained through measurements, in millimeters, of the inhibition zones promoted by the materials, using a digital caliper. In DCT, values of CFU/mL promoted by the three sealers were compared in three experimental periods (1 min, 1 h, and 24 h). The data were analyzed using Kruskal-Wallis and Dunn post-hoc tests (p < 0.05). In both ADT and DCT, GuttaFlow 2 presented no effect against E. faecalis, while Endofill and AH Plus showed similar inhibition zones. Endofill was the only material capable of reducing bacterial growth in DCT. In conclusion, modifications in the silver particle of GuttaFlow 2 did not result in a sealer with antibacterial effect against E. faecalis.