Penetration depth of irrigants into root dentine after sonic, ultrasonic and photoacoustic activation.

Aim: To compare penetration depths of endodontic irrigants into the dentinal tubules of extracted teeth when using several activation methods.

Methodology: The root canals of 90 extracted human teeth were prepared to size 40, .06 taper.

Cell Homing for Pulp Tissue Engineering with Endogenous Dentin Matrix Proteins.

Introduction: Compelling evidence pinpoints that pulp tissue engineering after the transplantation of stem cells is possible. Although intriguing, severe problems regarding clinical feasibility remain. Cell homing has been proposed as a viable alternative in which dentin-derived growth factors in a conducive scaffold may attract resident cells to form pulplike tissue.

Interactive effects of LPS and dentine matrix proteins on human dental pulp stem cells.

Aim: To investigate the combinatorial effects of lipopolysaccharide (LPS) and extracted dentine matrix proteins (eDMP) on regenerative and inflammatory responses in human dental pulp stem cells (DPSCs).

Methodology: Culture media were supplemented with several concentrations of LPS, eDMP and combinations of both. Cell viability was assessed over 1 week by MTT assay; cell survival was evaluated after 24 h and 7 days by flow cytometry.

Suitability of Different Natural and Synthetic Biomaterials for Dental Pulp Tissue Engineering.

Dental pulp tissue engineering is possible after insertion of pulpal stem cells combined with a scaffold into empty root canals. Commonly used biomaterials are collagen or poly(lactic) acid, which are either difficult to modify or to insert into such a narrow space. New hydrogel scaffolds with bioactive, specifically tailored functions could optimize the conditions for this approach.

A training model for revitalization procedures.

Aim: To develop an inexpensive simulation model for training of revitalization procedures.

Methodology: A replica of an immature maxillary central incisor was equipped with a mock blood reservoir at the root apex and embedded in a plaster model. Mock blood consisted of water supplemented with red pigments and fibrinogen, whilst thrombin was inserted into the root canal to allow for clot formation.

Dentine matrix proteins: isolation and effects on human pulp cells.

Aim: To establish a simplified and efficient protocol for the isolation and concentration of matrix proteins from human dentine, and to assess the effects of extracted dentine matrix proteins (eDMP) on the behaviour of human pulp cells.

Methodology: Matrix proteins were isolated from human dentine, purified, concentrated and characterized with protein and enzyme-linked immunosorbent assays (ELISA). Culture media were supplemented with eDMP in different concentrations, referred to as eDMP 1-10 000, to assess viability and proliferation of human pulp cells by DNA and MTT assays; apoptotic events were quantified by flow cytometry.

Ultrasonic activation of irrigants increases growth factor release from human dentine.

Objectives: Bioactive proteins are sequestered in human dentine and play a decisive role in dental pulp regeneration and repair. They can be released and exposed on the dentine surface by acids, but also chelators, such as ethylenediaminetetraacetic acid (EDTA). The objectives of this study were (i) to evaluate whether ultrasonic activation of irrigants in the root canal will promote growth factor release from dentine and (ii) to collect bioactive proteins in a physiological solution.

Three-dimensional culture of dental pulp stem cells in direct contact to tricalcium silicate cements.

Objectives: Calcium silicate cements are biocompatible dental materials applicable in contact with vital tissue. The novel tricalcium silicate cement Biodentine™ offers properties superior to commonly used mineral trioxide aggregate (MTA). Objective of this study was to evaluate its cytocompatibility and ability to induce differentiation and mineralization in three-dimensional cultures of dental pulp stem cells after direct contact with the material.

EDTA conditioning of dentine promotes adhesion, migration and differentiation of dental pulp stem cells.

Aim: To evaluate the effect of dentine conditioning on migration, adhesion and differentiation of dental pulp stem cells.

Methodology: Dentine discs prepared from extracted human molars were pre-treated with EDTA (10%), NaOCl (5.25%) or H2 O.

Influence of root canal disinfectants on growth factor release from dentin.

Introduction: During dentinogenesis, growth factors become entrapped in the dentin matrix that can later be released by demineralization. Their effect on pulpal stem cell migration, proliferation, and differentiation could be beneficial for regenerative endodontic therapies. However, precondition for success, as for conventional root canal treatment, will be sufficient disinfection of the root canal system.

Probing of microbial biofilm communities for coadhesion partners.

Investigations of interbacterial adhesion in dental plaque development are currently limited by the lack of a convenient assay to screen the multitude of species present in oral biofilms. To overcome this limitation, we developed a solid-phase fluorescence-based screening method to detect and identify coadhesive partner organisms in mixed-species biofilms. The applicability of this method was demonstrated using coaggregating strains of type 2 fimbrial adhesin-bearing actinomyces and receptor polysaccharide (RPS)-bearing streptococci.

Cell-free approaches for dental pulp tissue engineering.

The standard treatment modality for teeth with irreversibly damaged dental pulp is root canal therapy, which involves complete removal of the soft tissue and obturation with a synthetic material. So far, research studies show that the combination of stem cells with a suitable scaffold material and transplantation into the root canal may result in the generation of pulplike tissue and the formation of tubular dentin. Because of the technical challenges associated with such a procedure, cell-free alternatives that take advantage of the dental pulp's inherent regenerative capacity because of endogenous stem cell populations and bioactive dentin matrix components need to be considered and explored.

Salivary protein adsorption and Streptococccus gordonii adhesion to dental material surfaces.

Objectives: The initial adhesion of microorganisms to clinically used dental biomaterials is influenced by physico-chemical parameters like hydrophobicity and pre-adsorption of salivary proteins. Here, polymethyl methacrylate (PMMA), polyethylene (PE), polytetrafluoroethylene (PTFE), silicone (Mucopren soft), silorane-based (Filtek Silorane) and methacrylate-based (Tetric EvoCeram) dental composites, a conventional glassionomer cement as well as cobalt-chromium-molybdenum (Co28Cr6Mo) and titanium (Ti6Al4V) were tested for adsorption of salivary proteins and adhesion of Streptococcus gordonii DL1.

Methods: Wettability of material surfaces precoated with salivary proteins or left in phosphate-buffered saline was determined by the measurement of water contact angles.

Influences of protein films on antibacterial or bacteria-repellent surface coatings in a model system using silicon wafers.

Immobilization of defined chemical functionalities to biomaterial surfaces is employed to optimize them not only for tissue compatibility but also for prevention of bacterial infection. Grafting surfaces with chains of poly(ethylene glycol) (PEG) results in bacterial repellence whereas modification with cationic groups conveys them with bactericidal properties. Since biomaterials in situ will become exposed to a protein-rich environment, it is necessary to investigate the influence of prior protein adsorption on the antibacterial activity of this type of chemical surface modification.

The anti-adherence activity and bactericidal effect of microparticulate silver additives in composite resin materials.

Objective: Resin composite materials tend to accumulate microorganisms and dental plaque, which in turn may induce secondary caries around adhesive restorations. The aim of the present in vitro study was to evaluate the antibacterial activity of a resin composite material loaded with silver microparticles against Streptococcus mutans.

Design: Circular specimens (10.

Infection and immunity in broiler chicken breeders vaccinated with a temperature-sensitive mutant of Mycoplasma gallisepticum and impact on performance of offspring.

A comparison of infection and immunity to Mycoplasma gallisepticum (MG) in broiler chicken breeders vaccinated with a temperature-sensitive mutant of MG versus nonvaccinated chickens, and the impact on the performance of their offspring was conducted. Infection and immunity in breeders were assessed by culture and enzyme-linked immunoassay, respectively. However, performance in their offspring was assessed by studying MG infection in embryos, occurrence of infection titers to MG in relation to mortality, and feed conversion in the broilers.