Comparative Evaluation of Microtensile Bond Strength in Three Different Dentin Luting Agents: An In vitro Study.

Aim: Long-term clinical success on indirect restorations is largely determined by bonding efficiency of the luting agent, with adhesion to dentin being the main challenge. Therefore, aim of this study was to assess the microtensile bond strength when using flowable resin composite, preheated resin composite and dual self-adhesive resin cement as dentin luting agents. Materials and Methods: Occlusal thirds of molar teeth were cut and randomly divided into 3 groups to be cemented: RelyX™U200, Filtek™ Z250 XT- preheated to 70° and Filtek Flow™ Z350XT. They were then thermocycled 5000 times between 5+/-2°C and 55+/-2°C. Subsequently, 10 microbars per group were prepared. The 30 samples were placed in saline solution for 24 hours at room temperature prior to microtensile test. This was performed with a digital universal testing machine at a crosshead speed of 0.5 mm/min. The bond strength values obtained were analyzed in Megapascals (MPa). Measures of central tendency such mean and measures of dispersion such standard deviation were used. In addition, the Kruskall Wallis non-parametric test with Bonferroni post hoc test was applied, considering a significance value of 5% (P < 0.05), with type I error. Results: The dentin microtensile bond strengths of preheated resin composite, flowable resin composite and dual self-adhesive cement were 6.08 ± 0.66 Mpa, 5.25 ± 2.60Mpa and 2.82 ± 1.26Mpa, respectively. In addition, the preheated resin composite exhibited significantly higher microtensile bond strength compared to the dual self-adhesive cement (P < 0.001). While the flowable resin composite showed no significant difference with the dual self-adhesive cement (P = 0.054) and the preheated resin composite (P = 0.329). Conclusions: The microtensile bond strength in dentin was significantly higher when using a preheated resin composite at 70°C as a luting agent compared to dual self-adhesive cement. However, the preheated resin composite showed similar microtensile bond strength compared to the flowable resin composite.

Identification and Characterization of Potato Zebra Chip Resistance Among Wild Solanum Species.

Potato zebra chip (ZC) disease, associated with the uncultured phloem-limited bacterium, Candidatus Liberibacter solanacearum (CLso), is transmitted by the potato psyllid Bactericera cockerelli. Potato ZC disease poses a significant threat to potato production worldwide. Current management practices mainly rely on the control of the psyllid to limit the spread of CLso. The present study investigated new sources of ZC resistance among wild Solanum species. A taxonomically diverse collection of tuber-bearing Solanum species was screened; one ZC-resistant accession and three ZC-tolerant accessions were identified among the 52 screened accessions. Further characterization of the resistant accession showed that the resistance was primarily associated with antibiosis effects due to differences in leaf trichome density and morphology of the wild accession, which could limit the psyllid feeding and oviposition. This germplasm offers a good resource for further understanding ZC and psyllid resistance mechanisms, contributing to potato breeding efforts to develop ZC resistance cultivars. Alternatively, it could be used as a potential trap crop to manage psyllid and control ZC disease.

CRISPR/Cas9-Mediated Mutagenesis of the Granule-Bound Starch Synthase Gene in the Potato Variety Yukon Gold to Obtain Amylose-Free Starch in Tubers.

Potato (Solanum tuberosum L.) is the third most important food crop after rice and wheat. Its tubers are a rich source of dietary carbohydrates in the form of starch, which has many industrial applications. Starch is composed of two polysaccharides, amylose and amylopectin, and their ratios determine different properties and functionalities. Potato varieties with higher amylopectin have many food processing and industrial applications. Using Agrobacterium-mediated transformation, we delivered Clustered regularly interspaced short palindromic repeats and CRISPR-associated protein 9 (CRISPR/Cas9) reagents to potato (variety Yukon Gold) cells to disrupt the granule-bound starch synthase (gbssI) gene with the aim of eliminating the amylose component of starch. Lugol-Iodine staining of the tubers showed a reduction or complete elimination of amylose in some of the edited events. These results were further confirmed by the perchloric acid and enzymatic methods. One event (T2-7) showed mutations in all four gbss alleles and total elimination of amylose from the tubers. Viscosity profiles of the tuber starch from six different knockout events were determined using a Rapid Visco Analyzer (RVA), and the values reflected the amylopectin/amylose ratio. Follow-up studies will focus on eliminating the CRISPR components from the events and on evaluating the potential of clones with various amylose/amylopectin ratios for food processing and other industrial applications.

Identification of Proteins Associated with the Formation of Oral Biofilms

ABSTRACT Objective: To identify proteins associated with the formation of Streptococcus gordonii and Fusobacterium nucleatum biofilms. Material and Methods: Biofilms composed of two bacterial species, S. gordonii and F. nucleatum, were cultured for 1, 4, 7, and 10 days. The presence of both species was confirmed via amplification of the srtA and radD genes using real-time PCR. The concentrations of proteins associated with the biofilms and individual species were quantified using Western blotting. Results: The protein profiles of S. gordonii and F. nucleatum from individual cultures determined using one-dimensional electrophoresis revealed proteins found in S. gordonii and in F. nucleatum. Ct and reciprocal Ct values were determined for the exposed S. gordonii and F. nucleatum biofilms. Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) protein was detected in biofilms and F. nucleatum, whereas HSP40 protein was present only in biofilms after 7 and 10 days of formation. Conclusion: HSP40 was detected only in the formed biofilms; thus, HSP40 is an essential proteins for adhesion.

Chemical Composition and Antibacterial Effect of Plantago Major Extract on Periodontal Pathogens

Abstract Objective: To determine the in vitro antibacterial effect of different concentrations of the ethanol extract of Plantago major (plantain) on Porphyromonas gingivalis and Fusobacterium nucleatum. Material and Methods: Bacterial susceptibility tests were used in conjunction with the agar diffusion test and the minimum inhibitory concentration (MIC) test using the broth macrodilution technique. Results: Different concentrations of ethanol extract (25%, 50%, 75% and 100%) dissolved in 70% ethanol were used, with a positive control (0.12% chlorhexidine + 0.05% cetyl-pyridinium chloride) and a negative control (70% alcohol). The extracts at 75% and 100% showed inhibition halos against both strains studied. With 0.12% chlorhexidine + 0.05% cetyl-pyridinium chloride, inhibition halos averaged 14.9 mm, in contrast to 70º alcohol, where no bacterial inhibition was observed. The MIC was 50% for both species. Conclusion: The ethanol extract of Plantago major presents an in vitro antibacterial effect on Porphyromonas gingivalis, they may have potential applications in food and pharmaceutical products.