Osteoblast expression of cytokines is altered on MTA surfaces

Root-filling materials for endodontic surgery: biological and clinical aspects

The placement of root filling materials aims to prevent the occurrence of post-treatment apical periodontitis following completion of endodontic treatment. Materials should possess properties that will not permit bacterial invasion and infection, namely excellent sealing ability and/or antibacterial properties. In root-end filling procedures or repair of root perforations, the root filling materials are placed in a particularly challenging clinical environment, as they interface with a relatively large area with the periradicular tissues. The biological properties of these materials are therefore of significant importance. The current review discusses the most widely used materials for endodontic surgery (i.e., root-end filling and perforation repair), with particular focus on their biological characteristics, namely antibacterial properties and interactions with host tissue cells, together with clinical studies. Properties of amalgam, glass ionomer cements (GICs), resin systems, zinc oxide eugenol-based cements and hydraulic calcium silicate cements (HCSCs), together with representative and well-researched commercial materials in the context of their use in endodontic surgery are presented. While the use of HCSCs seems to offer several biological advantages, together with addressing issues with the initial formulation in the most recent versions, materials with different chemical compositions, such as zinc oxide eugenol-based cements, are still in use and appear to provide similar clinical success rates to HCSCs. Thus, the significance of the currently available materials on clinical outcomes remains unclear.

Hyperglycemic condition influence on mineral trioxide aggregate biocompatibility and biomineralization

This study aimed to investigate in vitro and in vivo the influence of hyperglycemic condition on biocompatibility and biomineralization of gray mineral trioxide aggregate (GMTA) and white mineral trioxide aggregate (WMTA). For the in vitro study, fibroblast-like cells L929 were cultured under high or normal glucose concentration to investigate the effects of both MTA's on cell proliferation and inflammatory cytokines production IL-1β, IL-6, and TNF-α. For the in vivo study, polyethylene tubes containing MTA materials and empty tubes were implanted into dorsal connective tissues of Wistar rats previously assigned normal and hyperglycemic. After 7 and 30 days, the tubes with surrounding tissues were removed and subjected to histological, fluorescence and immunohistochemical analyzes of IL-1β, IL-6, and TNF-α. In vitro study showed that, under high glucose condition, GMTA reduced cell proliferation and IL-6 production compared with WMTA. Moreover, in vivo study revealed that hyperglycemic condition did not modify the inflammatory response and cytokines production in the tissue close to both materials. Independently of hyperglycemic status, mineralized areas were observed with both materials, but the fluorescence intensity of WMTA was diminished on 14 days in hyperglycemic animals. It is possible to conclude that GMTA was able to inhibit the proliferation rate and IL-6 production under high glucose concentration in vitro. Furthermore, cytokines production and inflammatory response were not upregulated in hyperglycemic animals; however, a decrease in the calcium deposition was observed in presence of WMTA, suggesting a delay in the mineralization process.

Implant Placement in Failed Endodontic Sites: A Review

Dental implants may fail to osseointegrate in sites of endodontic failure. This may occur as a result colonization by various anaerobic and facultative bacterial species. If an implant is placed in a site where vegetative bacteria are residing, the implant may fail to integrate if a bacterial colonization proceeds coronally. If the implant apical cortical bone is thin or if there is an apical fenestration, the colonization may proceed through the thin or nonexistent bone through the covering mucosa, relieving inflammatory pressure to create an apical (retrograde) peri-implantitis. Enterococcus faecalis may be the prime culprit in these types of implant failures. After thorough debridement, the implant may be immediately placed after extraction of an endodontically failed tooth, and the patient treated with an appropriate antibiotic. Alternatively waiting for postextraction healing and subsequent implant placement can be done. Nevertheless, either way may allow for the formation of bacterial vegetative forms or biofilms. The implant surface may be colonized when the surface is exposed to the bacteria. Thorough debridement is crucial. Nonetheless, organisms may persist. Randomized controlled trials are needed to elucidate this issue.

A comparison of the cytotoxicity and proinflammatory cytokine production of EndoSequence root repair material and ProRoot mineral trioxide aggregate in human osteoblast cell culture using reverse-transcriptase polymerase chain reaction

INTRODUCTION

The purpose of this study was to compare the cytotoxicity and cytokine expression profiles of EndoSequence Root Repair Material (ERRM; Brasseler, Savannah, GA) putty, ERRM flowable, and ProRoot mineral trioxide aggregate (MTA; Dentsply Tulsa Dental, Johnson City, TN) using osteoblast cells (MG-63).

METHODS

Four millimeters in diameter of each material was placed in the center of a 6-well culture plate, and a 2-mL suspension (10(5) cells/mL) of human osteoblasts was seeded in each well. Photomicrograph images were used to evaluate cytotoxicity as evidenced by the lack of osteoblast cell growth in relation to the materials with AH-26 (Dentsply Tulsa Dental) as the positive control. In addition, reverse-transcriptase polymerase chain reaction (RT-PCR) was used to evaluate the expression of interleukin (IL)-1β, IL-6, IL-8, and tumor necrosis factor-α (TNF-α). Cytokine expression of MG-63 cells upon lipopolysaccharide treatment was used as controls. RT-PCR results were normalized by the expression of the housekeeping gene β-actin and were used to measure cytokine expression. Statistical analysis was performed using analysis of variance.

RESULTS

Results showed that ERRM putty and MTA exhibited minimal levels of cytotoxicity; however, ERRM was slightly more cytotoxic although not statistically significant. The expression of IL-1β, IL-6, and IL-8 was detected in all samples with minimal TNF-α expression.

CONCLUSIONS

We concluded that ERRM and MTA showed similar cytotoxicity and cytokine expressions.

Nano-TiO 2 Enriched Polymeric Powder Coatings Support Human Mesenchymal Cell Attachment and Growth

The objective of this study was to utilize ultrafine powder coating technology to prepare (PPC) that can support human mesenchymal cell attachment and growth. Resins were modified with titanium dioxide and polytetrafluoroethylene (PTFE), and enriched with either SiO2 or TiO2 nanoparticles (nSiO2 or nTiO2) to create continuous PPC. Scanning electron microscopy (SEM) revealed complex surface topographies with nano features, and energy dispersive X-ray (EDX) analysis with Ti mapping confirmed a homogenous dispersion of the material. SEM and inverted fluorescence microscopy showed that human embryonic palatal mesenchymal (HEPM) cells attached and spread out on the PPC surfaces, particularly those enriched with nTiO 2. Cell counts were higher, and the MTT assay measured more metabolic activity from the nTiO2 enriched PPCs. Furthermore, these cellular responses were enhanced on PPC surfaces that were enriched with a higher concentration of nTiO2 (2% vs. 0.5%), and appeared comparable to that seen on commercially pure titanium (cpTi). Therefore the nTiO 2 enrichment of PPC was shown to favor human mesenchymal cell attachment and growth. Indeed, this modification of the materials created continuous surface coatings that sustained a favorable cellular response.