Successful Use of MTA Fillapex as a Sealant for Feline Root Canal Therapy of 50 Canines in 37 Cats

Intentional or unintentional pulp exposure of cat canines can lead to periapical disease, osteomyelitis, and oral pain. Root canal therapy (RCT) allows the retention of cat canines with pulp exposure by removing the infected pulp and replacing it with an inert material. This study used MTA Fillapex™ as a root canal sealant with gutta percha single cone obturation in 37 cats (50 canine teeth). Roots were classified as "successful," "no evidence of failure (NEF)," or "failed" at 6-month radiographic reviews. Therapy was considered "successful" if a preoperative periapical lucency had healed or not formed after treatment and any preoperative external inflammatory root resorption (EIRR) had stabilized without progression. Therapy was categorized as "NEF" if a periapical lucency had remained the same or decreased in size but not completely resolved and any preoperative EIRR had stabilized without progression. "Failed" if a periapical lucency had occurred or increased in size posttreatment or if EIRR had developed or progressed posttreatment. Thirty-two canine teeth (64%) were classified as "successful," 14 canine teeth (28%) were classified as "NEF," and 4 canine teeth (8%) were classified as "failed". The study concluded that RCT using MTA Fillapex as a root canal sealant is a suitable endodontic treatment for fractured cat canines, especially those that are periodontally or endodontically challenged.

MTT versus other cell viability assays to evaluate the biocompatibility of root canal filling materials: a systematic review

OBJECTIVES

This systematic review aimed to compare the cytotoxicity of root canal filling materials (RCFMs) assessed using tetrazolium salt-based tests (TSBT), including the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, with those obtained using other cell viability assays.

METHODS

A search was performed on PubMed, Scopus, Web of Science and OpenGrey up to March 2019, followed by a manual search. According to the Participants, Exposure, Comparator and Outcomes (PECO) criteria, in vitro studies that evaluated the cytotoxic effect of RCFMss on animal and/or human cells through TSBT and at least one other viability assay were compared. The methodological quality of selected papers was assessed using ToxRTool^® and SciRAP^® . Data were analysed using Wilcoxon's signed-rank test for paired samples and linear weighting kappa.

RESULTS

A total of 230 non-duplicated records were identified. After applying the eligibility criteria, 55 studies were selected for methodological evaluation, seven were selected by manual searching, 22 were excluded for methodological reasons, and 40 were included. A total of 410 comparisons were performed between TSBT and distinct cell viability tests (DCVT). MTT had moderate concordance with DCVT using human cells (n = 138 samples) (P = 0.507; k = 0.4225) and animal cells (n = 122 samples) (P = 0.124; k = 0.5775). XTT had good concordance using human (n = 110 samples) (P = 0.507; k = 0.6336) and animal cells (n = 12 samples) (P = 0.564; k = 0.6604). MTT, XTT, WST and MTS assays showed moderate concordance with DCVT (n = 410 samples) (P = 0.375; k = 0.5138) and complete agreement in 226 samples.

DISCUSSION

The included studies had methodological heterogeneity that was minimized by the systematic review methodology.

CONCLUSIONS

MTT and XTT do not cause over- or underestimation of cell viability during cytotoxicity screening of root canal filling materials, implying that these assays can be considered reliable for this purpose. Nonetheless, the development of protocols for the cytotoxic screening of these materials on 3D tissue-like cultures aiming to improve their predictability in the clinical scenario is suggested.

A protein chimera self-assembling unit for drug delivery

In the modern view of selective drug delivery of bioactive molecules, the attention is moving onto the setup of the perfect carrier more than in the optimization of the active compound. In this respect, virus-like particles constitute bioinspired nanodevices with the intrinsic ability to transport a large class of molecules, ranging from smart drugs to small interfering RNAs. In this work, we demonstrate the efficacy of a novel construct obtained by fusing a self-assembling protein from the human Rotavirus A, VP6, with the Small Ubiquitin Modifier domain, which maintains the ability to form nanoparticles and nanotubes and is able to be used as a drug carrier, even without specific targeting epitopes. The high expression and purification yield, combined with low toxicity of the empty particles, clearly indicate a good candidate for future studies of selective drug delivery. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 35: e2769, 2019.

Correlation Between Metabolic Syndrome, Periodontitis and Reactive Oxygen Species Production. A Pilot Study

Background and Objective:

Metabolic syndrome (MetS) is associated with an increased risk of periodontitis even if the mechanism is unknown. Since both MetS and periodontitis are characterized by an alteration of inflammation status, the aim of this pilot study was to determine if differences in ROS metabolism of phagocytes isolated from (A) patients with MetS, (B) patients with both MetS and mild periodontitis, (C) healthy subjects and (D) normal weight subjects with mild periodontitis, were present.

Methods:

ROS metabolism was studied by a Chemiluminescence (CL) technique: the system was made up of luminol (100 nmol/L) and cells (1 × 10⁵) in the presence or absence of stimulus constituted by opsonized zymosan (0.5 mg). The final volume (1.0 mL) was obtained using modified KRP buffer. ROS production was measured at 25°C for 2 h, using an LB 953 luminometer (Berthold, EG & G Co, Germany). All the experiments were performed in triplicate.

Statistical Analysis:

All results are mean ± standard deviation (SD). The group of means was compared by the analysis of variance "(ANOVA)". A value of p < 0.05 was considered significant.

Results:

Results showed that basal ROS production (both from PMNs and from PBMs) of groups A, B and D was increased with respect to that obtained from group C (p <0.05).

Conclusion:

These results are congruent with literature data, although the actual clinical relevance of the phenomenon remains to be evaluated.

Effects of barriers on chemical and biological properties of two dual resin cements

The aim of this study was to investigate the degree of conversion, monomer release, and cytotoxicity of two dual-cure resin cements (Cement-One and SmartCem2), light-cured across two indirect restorative materials in an attempt to simulate in vitro the clinical conditions. The results obtained show that the degree of conversion was influenced by both barriers, but the effect of the composite material was greater than that of the ceramic one. The amount of monomers released from the polymerized materials in the absence of barriers was significantly lower than that released in the presence of either the ceramic or the composite barrier. However, a higher amount of monomers was released in the presence of the ceramic barrier. All materials, in all the experimental conditions employed, induced slight cytotoxicity (5-10%) on human pulp cells. Our examinations showed that the two resin cements had similar chemical and biological properties. The decreased degree of conversion of the dual-curing self-adhesive composite showed that the light-curing component of these materials has an important role in the polymerization process. In clinical practice, it is therefore important to pay attention to the thickness of the material used for the reconstruction.

Biocompatibility of new nanostructural materials based on active silicate systems and hydroxyapatite: in vitro and in vivo study

AIM

To evaluate in vitro cytotoxicity and in vivo inflammatory response to new nanostructural materials based on active calcium silicate systems (CS) and hydroxyapatite (HA-CS).

METHODOLOGY

Cytotoxicity of eluates of new nanostructural noncommercial materials CS and HA-CS, and MTA (White MTA, Angelus(®) Soluções Odontológicas, Londrina, Brazil) as a control, were tested using the MTT assay on MRC-5 cells. Eluates of set materials were tested in 100% and 50% concentrations, 24 h, 7 days and 21 days post-elution. The pH values were determined for undiluted eluates of set materials. Polyethylene tubes containing the test materials (CS, HA-CS, MTA) were implanted in subcutaneous tissue of Wistar rats. Histopathological examinations were conducted at 7, 15, 30 and 60 days after the implantation. Data were statistically analyzed using three-way and one-way anova Tukey's post hoc test as well as Kruskall-Wallis test with Dunn's post hoc test at α = 0.05.

RESULTS

All materials significantly reduced cell viability; especially when undiluted eluates were used (P < 0.001). After 24 h elution, cell viability was 10 ± 1.8%, 49.5 ± 4.2% and 61 ± 7.4%, for MTA, and HA-CS, respectively. However, CS and HA-CS were significantly less toxic than the control material MTA (P < 0.05). Cytotoxicity could be at least partially attributed to pH kinetics over time. Dilution of eluates of all tested materials resulted in better cell survival. Histopathological examination indicated similar inflammatory reaction, vascular congestion and connective tissue integrity associated with CS, HA-CS and MTA at each observation period (P > 0.05). The only significant difference was found for capsule thickness, that is thicker capsule was associated with HA-CS compared to MTA at 60 days (P = 0.0039). HA-CS induced moderately thick capsules (median score 3, score range 2-3), whereas MTA resulted in thin capsule formation (median score 2, score range 1-3).

CONCLUSIONS

Evaluation of cytotoxicity and inflammatory response indicated better biocompatibility of CS and HA-CS, in comparison with MTA (White MTA, Angelus(®) Soluções Odontológicas, Londrina, Brazil).

Nutrition and Cancer Prevention

Cancer cells invade surrounding tissues and metastasize to distant sites. Diet high in fat is a strong link to, and perhaps causes, a high incidence of tumours. Trans-fatty acid might impair the function and it could be involved in the development of cancer. Cholesterol is also strongly suspected to be involved in the development of tumours, therefore it is important for everyone to eat well, especially for people with cancer to prevent the body tissues from breaking down and helping to rebuild the normal tissue that may have been affected by the treatments. Factors secreted by adipocytes and macrophages such as TNF-alpha and other inflammatory proteins are involved in inflammation in cancer. In addition, MCSF which up-regulates adipocyte tissue is also important for the stimulation of fat cell proliferation and is expressed by human adipocytes. Many cytokines, such as IL-1, IL-6, IL-8, IL-32, IL-33 and MCP-1, are biomarkers for cancer and chronic diseases along with transcription factors NFkB and AP-1; these last two factors are important bioactive substances on the molecular mechanism of the control of genes which in turn affect cellular metabolism. In this paper we revisit the interrelationship between cancer and metabolism.