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In some clinical cases, attending to the type and extension of the Achilles tendon injury, a partial replacement of the tissue may be needed. Driven by this, the authors developed different structures based on polypropylene (PP) or poly (ethylene terephthalate) (PET) multifilament yarns, using a textile technology-based technique, in order to mimic the fibrous structure of tendons. Those structures are based on a core/shell system, being the core composed by several sub-components (braids) and the shell based on braided yarns enclosing the core. It was observed that the load at failure of ropes is mainly defined by the number of yarns that compose it, but the strain level is mostly influenced by the production take-up rate of the core braids and consequently by the braid angle. The ropes stiffness level results from a combination of the yarns number and braid angle of the core braids. The structure based on PET yarns revealed a non-linear force-strain curve similar to a typical curve of a natural Achilles tendon (AT), presenting a load at failure, strain to failure and stiffness levels very promising for AT replacement. Moreover, the PET rope also revealed a very promising fatigue and appropriate creep resistance for the final application, being in accordance with what has been reported for native AT. [ABSTRACT FROM AUTHOR]

Gutta-percha cones should be free of pathogenic microorganisms before being used for root canal filing. This study was carried out to evaluate the effectiveness of four chemical agents in eliminating Bacillus subtilis spores from gutta-percha cones. The solutions tested were 5.25% sodium hypochlorite, 2% glutaraldehyde, 2% chlorhexidine digluconate, and 70% ethyl alcohol. The gutta-percha cones coated with spores were placed into contact with the chemical agents for 1. 3. 5 and 10 min. The results showed that 5.25% sodium hypochlorite was effective in destroying the spores after 1 min of contact. Glutaraldehyde, chlorhexidine and ethyl alcohol did not decontaminate the gutta-percha cones even after 10 min of contact. [ABSTRACT FROM AUTHOR]

Endodontic sealers that possess both optimum flow ability and antimicrobial properties may theoretically assist in the elimination of microorganisms located in confined areas of the root canal system. The antimicrobial effects and the flow rate of the following sealers were investigated and compared: Kerr Pulp Canal Sealer EWT, Grossman's Sealer, ThermaSeal, Sealer 26, AH Plus, and Sealer Plus. The agar diffusion test was used to assess the antimicrobial activity of the sealers. In the flow assay, the sealers were placed between two glass slabs and a weight of 500 g was placed on the top of the glass. The diameters of the formed discs were recorded. All root canal sealers tested showed some antimicrobial activity against most of the microorganisms. There were no significant differences between the materials tested (p > 0.05). All root canal sealers also flowed under the conditions of this study. Statistical analysis of the results revealed that AH Plus and Kerr Pulp Canal Sealer EWT had flow values significantly superior to the other sealers tested (p > 0.05). Taken together, these findings suggest that these sealers have the potential to help in the microbial control in the root canal system.

The in vitro reduction of the bacterial population in the root canal by the mechanical action of instrumentation and irrigation was evaluated. Root canals inoculated with a Enterococcus faecalis suspension were instrumented using hand Nitiflex files, Greater Taper (GT) files, and Profile 0.06 taper Series 29 rotary instruments. Irrigation was performed using sterile saline solution. Root canals were sampled before and after instrumentation. In the group of the Nitiflex files, samples were also taken after each file size. After serial dilution, samples were plated onto Mitis-Salivarius agar, and the colony forming units grown were counted. All techniques and instruments tested were able to reduce significantly the number of bacterial cells in the root canal. Instrumentation to a Nitiflex #30 was significantly more effective than GT files. There were no significant differences when comparing the effects of the Profile instrument #5 with either the GT files or the Nitiflex #30. Enlargement to a Nitiflex #40 was significantly more effective in eliminating bacteria when compared with the other techniques and instruments tested (p < 0.05). The results of this study showed that the instrumentation and irrigation can mechanically remove more than 90% of bacterial cells from the root canal.

This in vitro study evaluated the coronal leakage of human saliva into root canals filled by lateral condensation of gutta-percha using two root canal sealers containing calcium hydroxide. Obturated canals with gutta-percha and either Sealapex of Sealer 26 were mounted in an apparatus and then exposed to saliva. The number of days required for total recontamination of the root canal was recorded. Evaluation was conducted for 60 days. Thirty-five percent of the specimens of the Sealer 26 group showed entire recontamination at 60 days. Eighty percent of the root canals obturated with Sealapex showed complete recontamination at 60 days. Sealer 26 presented significantly less leakage than Sealapex (p < 0.01).

The purpose of this investigation was to evaluate the occurrence of apical transportation after root canal instrumentation using only K-Flexofiles or K-Flexofiles intercalated with K-Flexofile Golden Mediums. For this purpose, the degree (Schneider's method) and the radius of the curvature was recorded before and after instrumentation. The results showed that there was no statistically significant difference between the techniques. The correlation between the degree and the radius of curvature of the root canal was not consistent, nor was there a relationship between the original radius of curvature and the apical transportation. However, determination of curvature by use of its radius has proved to be an effective method.

This in vitro study evaluated the ability of some medications to prevent recontamination of coronally unsealed root canals by bacteria from saliva. The medications tested were camphorated paramonochlorophenol (CPMC) applied in cotton pellets in the pulp chamber; calcium hydroxide/saline solution paste filling the root canal; and calcium hydroxide/CPMC/glycerin paste also filling the root canal. Medicated canals were exposed to saliva, and the number of days required for total recontamination to occur was recorded. Canals medicated with CPMC in cotton pellets were thoroughly recontaminated within an average of 6.9 days. Canals filled with calcium hydroxide/saline solution and calcium hydroxide/CPMC/glycerin showed entire recontamination within an average of 14.7 and 16.5 days, respectively. Calcium hydroxide pastes were significantly more effective than CPMC (p < 0.05).

The effectiveness of 4.0% sodium hypochlorite (NaOCl) used with three irrigation methods in the elimination of Enterococcus faecalis from the root canal was tested in vitro. Root canals contaminated with E. faecalis were treated as follows: (i) irrigation with 2 mL of NaOCl solution and agitation with hand files; (ii) irrigation with 2 mL of NaOCl solution and ultrasonic agitation; (iii) irrigation with NaOCl alternated with hydrogen peroxide. Contaminated canals irrigated with sterile saline solution served as the control. Paper points used to sample bacteria from the root canals were transferred to tubes containing 5 mL of brain heart infusion (BHI) broth. Tubes were incubated and the appearance of broth turbidity was indicative of bacteria remaining in the root canal. There were no statistically significant differences between the experimental groups. However, NaOCl applied by the three methods tested, was significantly more effective than the saline solution (control group) in disinfecting the root canal.

The aim of this study was to determine the variation of the shaft diameter close to the active cutting region and close to the radius of concordance of 28- and 32-mm Gates-Glidden drills and to analyze the diameter influence on the torsion fracture resistance. Seventy-two stainless steel Maillefer drills were studied. The drill diameter varied along the shaft, the smallest diameter occurring close to the radius of concordance. This variation causes stress concentration which leads to complete fracture of the instrument.