R.T. Basting

Titanium tetrafluoride incorporated into a two-step self-etching adhesive system: physico-mechanical characterization and bonding stability

OBJECTIVESnTo evaluate the influence of TiF4 incorporated into the primer (P) or bond (B) of a self-etching adhesive system on long-term dentin bonding, and evaluate the physico-mechanical properties of TiF4-containing adhesives.nnnMETHODSnDentin surfaces received the following treatments (n = 8): CL (Clearfil SE Bond); TiF4CL (dentin pretreatment with TiF4 aqueous solution + CL); TiF4P (TiF4 incorporated into the P); TiF4B (TiF4 incorporated into the B). Microtensile bond strength (µTBS) and failure mode evaluations were performed after 24h, 6 months and one year, respectively. Degree of conversion (DC) and flexural strength (FS) were evaluated to determine whether TiF4 influenced adhesive properties. Particle size (PS), polydispersity index (PI) and zeta potential (ZP) of TiF4-containing adhesives were measured using dynamic light scattering. Two-way ANOVA for repeated measures was applied to µTBS data, and one-way ANOVA and Tukey tests to DC and FS results.nnnRESULTSnThere was no difference in µTBS among the groups (p = 0.818) regardless of time; the µTBS in each group was not significantly affected over time (p = 0.061). TiF4P and TiF4B significantly affected FS (p = 0.004). The DC for TiF4P was not significantly different from that of CL, and higher than that of TiF4B. Lower average particle size was observed for TiF4P at baseline. TiF4 aqueous solution showed a tendency to agglomerate.nnnCONCLUSIONSnTiF4-containing adhesives did not influence µTBS or failure mode to dentin over time, although FS and DC were affected, especially when TiF4 was incorporated into the B. TiF4P presented excellent stability over time.

Resin-dentin bond stability and physical characterization of a two-step self-etching adhesive system associated with TiF4

OBJECTIVESnTo evaluate the bond strength to superficial (SD) and deep (DD) dentin after the use of 2.5% (T2.5%) or 4% (T4%) titanium tetrafluoride (TiF4) in aqueous solution as a dentin pretreatment, or when incorporated into the primer (T2.5%P and T4%P) of an adhesive system (Clearfil SE Bond/CL). Degree of conversion (DC), particle size (PS), polydispersity index (PI) and zeta potential (ZP) of the solutions were evaluated.nnnMETHODSnFifty molars were sectioned longitudinally to obtain two slices of each tooth, which were demarcated into SD and DD. Treatments were applied (n=10): CL; T2.5%; T4%; T2.5%P; T4%P. After 24h or 180days storage, microshear bond strength tests were performed. The DC values of T2.5%P and T4%P were evaluated by FTIR. PS, PI and ZP were measured using dynamic light scattering.nnnRESULTSnAnalysis of mixed models showed significant effect of concentration of TiF4 * solution * storage time (p=0.0075). There were higher bond strength values in SD than in DD (p=0.0105) for all treatments in both times. The failure mode showed adhesive failures in the majority of groups, irrespective of depth and time (p=0.3746). The bond strength values were not affected by treatments. Lower average particle size was observed for T2.5%P and T4%P at baseline. T2.5% and T4% showed a trend towards agglomeration.nnnSIGNIFICANCEnHigher bond strength values were achieved at SD for all treatments and times. The failure modes observed were adhesive. TiF4 incorporation did not affect DC. T2.5%P and T4%P presented excellent stability over time.

Antifungal, antibiofilm, and antiproliferative activities of Guapira graciliflora Mart

The aim of this study was to evaluate in vitro the antifungal, antibiofilm and antiproliferative activities of the extract from the leaves of Guapira graciliflora Mart. The phytochemical characterization of the extract was performed using electrospray ionization mass spectrometry (ESI-MS). The antimicrobial activity of the extract and its fractions was evaluated using the broth microdilution method against species of Candida. The inhibition of C. albicans biofilm was evaluated based on the number of colony-forming units (CFU) and metabolic activity (MTT). The antiproliferative activity of the extract and its fraction was evaluated in the presence of human tumor and non-tumor cells, and the cytotoxicity of the extract was determined on the RAW 264.7 macrophage line - both using the sulforhodamine B method. The phytochemical characterization indicated the presence of the flavonoids rutin and kaempferol. The extract and the methanol fraction exhibited moderate antifungal activity against C. albicans, C. krusei, and C. glabrata, and strong activity against C. dubliniensis. In the biofilms at 24 and 48 hours, the concentration of 12500 µg/mL of the extract was the most effective at reducing the number of CFU s/mL (44.4% and 42.9%, respectively) and the metabolic activity of C. albicans cells (34.6% and 52%, respectively). The extract and its fractions had no antiproliferative effect on the tumor lines tested, with mean activity (log GI50) equal to or greater than 1.71 µg/mL. Macrophage cell viability remained higher than 80% for concentrations of the extract of up to 62.5 µg/mL. G. graciliflora has flavonoids in its chemical composition and demonstrates potential antifungal and antibiofilm activity, with no evidence of a significant change in the viability of human tumor and non-tumor cell lines.

Microhardness evaluation of enamel submitted to bleaching with hydrogen peroxide

box (BWIM%); Lingual wall of proximal box (LWIM%); Gingival floor of proximal box (GFIM%); Mesial floor of pulpal cavity (MFIM%); Distal floor of pulpal cavity(DFIM%). To compare the difference, both two-way and one-way ANOVA with Scheffe test was applied at 95% confidence interval. Results:As formarginal adaptation,%IMwas in the order of Group 4, 5 =Group 1, 3 =Group 2 (p<0.05). As for internal adaptation, %IM was in the order of group 4,5 = group 1,2 = group 3 (p<0.05). %IM was higher after thermo-mechanical loading than before loading in marginal adaptation (p<0.05). As for cavity walls, BWIM%, MFIM% <GFIM%, MFIM%, DFIM% (p<0.05) in the internal adaptation. Conclusion:NFB-RBCs showed the same or bettermarginal & internal adaptation than FB-RBCs.