Assaying endogenous matrix metalloproteinases (MMPs) in acid-etched dentinal cavity walls.

Endogenous dentinal matrix metalloproteinases (MMPs) have been implicated in the auto-degradation of collagen fibrils within resin infiltrated layers of dentinal attachment. In order to target these proteinases, we must know which MMPs are produced and activated at the resin/dentin interface. In this study, we have optimized an extraction procedure and quantitated levels of endogenous MMPs in samples of dentin removed from the cavity walls of a single, extracted tooth.

Evolution of resistance to cationic biocides in Streptococcus mutans and Enterococcus faecalis.

Objectives: The aim of this study was to investigate whether Streptococcus mutans and Enterococcus faecalis develop resistance to the cationic biocides chlorhexidine (CHX), cetylpyridinium chloride (CPC), and 12-methacryloyloxydodecylpyridinium bromide (MDPB).

Methods: The minimum inhibitory concentrations (MICs) of CHX, CPC, and MDPB were assessed after repeated exposure of S. mutans and E.

Development of an antibacterial root canal filling system containing MDPB.

An antibacterial monomer 12-methacryloyloxydodecylpyridinum bromide (MDPB)-containing experimental, chemically cured primer was prepared to develop a new resin-based root canal filling system. This study investigated the antibacterial effects of the MDPB-containing primer (experimental primer [EP]) against Enterococcus faecalis and assessed the in vitro bonding and sealing abilities of the filling system, consisting of EP and a Bis-GMA-based sealer resin. Antibacterial effects of EP were evaluated by contact with planktonic or adherent bacteria for 30 or 60 sec, and the viable bacterial number was counted.

Development of sustained antimicrobial-release systems using poly(2-hydroxyethyl methacrylate)/trimethylolpropane trimethacrylate hydrogels.

Reconstructive materials with sustained antimicrobial effects could be useful for preventing infectious diseases in an environment containing indigenous bacteria or fungi such as the oral cavity. With the objective of applying a non-biodegradable hydrogel to resin-based materials as a reservoir for water-soluble antimicrobials, novel hydrogels consisting of 2-hydroxyethyl methacrylate (HEMA) and trimethylolpropane trimethacrylate (TMPT) were fabricated. Cetylpyridinium chloride (CPC) was loaded into five hydrogels comprising different ratios of HEMA/TMPT, and their ability to release as well as to be recharged with CPC was examined in vitro.

Mechanism of detoxification of the cationic antibacterial monomer 12-methacryloyloxydodecylpyridiniumbromide (MDPB) by N-acetyl cysteine.

Objectives: The protective effects of N-acetyl cysteine (NAC) against cytotoxicity induced by conventional dental resin monomers have been widely documented. However, its effectiveness to detoxify cationic antibacterial monomers has not yet been elucidated. The aim of the present study was to investigate the possible protective effects of NAC against the cytotoxicity of 12-methacryloyloxydodecylpyridiniumbromide (MDPB) and explore the role of adduct formation in NAC-directed detoxification.

In vitro precision of fit of computer-aided design and computer-aided manufacturing titanium and zirconium dioxide bars.

Objectives: Optical scanners combined with computer-aided design and computer-aided manufacturing (CAD/CAM) technology provide high accuracy in the fabrication of titanium (TIT) and zirconium dioxide (ZrO) bars. The aim of this study was to compare the precision of fit of CAD/CAM TIT bars produced with a photogrammetric and a laser scanner.

Methods: Twenty rigid CAD/CAM bars were fabricated on one single edentulous master cast with 6 implants in the positions of the second premolars, canines and central incisors.

Assessment of bactericidal effects of quaternary ammonium-based antibacterial monomers in combination with colloidal platinum nanoparticles.

Pretreatment of dentin using colloidal platinum nanoparticles (CPtN) can enhance the bond strength of dentin adhesives. However, the combination of CPtN, which is negatively charged, with cationic monomer-containing adhesive may reduce the antibacterial activity of the original material. Thus, the purpose of this study was to assess the effect of CPtN on the bactericidal activity of two cationic antibacterial monomers, 12-methacryloyloxydodecylpyridinium bromide (MDPB) and methacryloxylethyl cetyl dimethyl ammonium chloride (DMAE-CB).

Evaluation of cytotoxic effects of six self-etching adhesives with direct and indirect contact tests.

This study evaluated the cytotoxicity of self-etching primers/adhesives by direct contact and dentin barrier tests. The three two-step self-etching systems Clearfil SE Bond (CSE), Clearfil Protect Bond (CPB), Prime&Bond NT/NRC (PB) and one-step self-etching systems Reactmer Bond (RB), Clearfil Tri-S Bond (CTS), and Adper Prompt L-Pop (AP) were examined. In direct contact tests, L929 cells were cultured in the presence of diluted solutions (50, 20, 10, and 1%) of primer/conditioner of adhesive systems.

Antibiofilm effects of azithromycin and erythromycin on Porphyromonas gingivalis.

Antibiotic resistance of biofilm-grown bacteria contributes to chronic infections, such as marginal and periapical periodontitis, which are strongly associated with Porphyromonas gingivalis. Concurrent azithromycin (AZM) administration and mechanical debridement improve the clinical parameters of periodontal tissue in situ. We examined the in vitro efficacy of AZM against P.

Effects of the antibacterial monomer 12-methacryloyloxydodecylpyridinium bromide (MDPB) on bacterial viability and metabolism.

The antibacterial monomer 12-methacryloyloxydodecylpyridinium bromide (MDPB) is a strong bactericide when unpolymerized and has the potential to be utilized in various resinous biomaterials. To analyze the antibacterial characteristics of this monomer in detail, the ability of high concentrations of unpolymerized MDPB to kill Streptococcus mutans in planktonic or biofilm forms within a short time-period of contact, and the inhibitory effects of low concentrations of MDPB on the metabolic function of S. mutans, were examined.

Proliferation and differentiation potential of pluripotent mesenchymal precursor C2C12 cells on resin-based restorative materials.

This study investigated the proliferation and differentiation potential of pluripotent mesenchymal cells on three resin-based restoratives using a typical pluripotent mesenchymal precursor cell line, C2C12. C2C12 cells were cultured for 3-21 days on cured specimens of a Bis-GMA/TEGDMA-based composite resin (APX; Clearfil AP-X), a 4-META/MMA-based resin cement (SB; Superbond C&B) or a HEMA-containing resin modified glass-ionomer (LC; Fuji Ionomer Type II LC). To examine the influences on differentiation potential, alkaline phosphatase (ALP) activity of the cells cultured on each material was determined.

Antibacterial effects of MDPB against anaerobes associated with endodontic infections.

Aim: To investigate the antibacterial effects of 12-methacryloyloxydodecylpyridinium bromide (MDPB), an antibacterial monomer synthesized by combining quaternary ammonium with a methacryloyl group, against three anaerobes associated with endodontic infections using planktonic and biofilm cells.

Methodology: The antibacterial activity of unpolymerized MDPB against Enterococcus faecalis, Fusobacterium nucleatum and Prevotella nigrescens was examined by agar-disc diffusion tests and determination of the minimum inhibitory/bactericidal concentrations (MIC/MBC). Rapid killing effects of MDPB against three bacteria in planktonic form were examined by a cell number counting method, and those against biofilm cells were assessed by a viability staining method.

Synthesis and optimization of hyaluronic acid-methotrexate conjugates to maximize benefit in the treatment of osteoarthritis.

We previously reported that a conjugate of hyaluronic acid (HA) and methotrexate (MTX) could be a prototype for future osteoarthritis drugs having the efficacy of the two clinically validated agents but with a reduced risk of the systemic side effects of MTX by using HA as the drug delivery carrier. To identify a clinical candidate, we attempted optimization of a lead, conjugate 1. Initially, in fragmentation experiments with cathepsins, we optimized the peptide part of HA-MTX conjugates to be simpler and more susceptible to enzymatic cleavage.

Novel hyaluronic acid-methotrexate conjugates for osteoarthritis treatment.

Hyaluronic acid (HA) provides synovial fluid viscoelasticity and has a lubricating effect. Injections of HA preparations into the knee joint are widely used as osteoarthritis therapy. The current HA products reduce pain but do not fully control inflammation.

Association of salivary Streptococcus mutans levels determined by rapid detection system using monoclonal antibodies with prevalence of root surface caries.

Purpose: To examine the hypothesis that salivary Streptococcus mutans levels determined by a rapid detection system using monoclonal antibodies are associated with prevalence of root surface caries in a selected population of older adults.

Methods: Oral examinations were performed in 241 elderly people aged over 60 years with at least 10 teeth, and root surface caries were recorded. Populations of S.

Comparative study of flux redistribution of metabolic pathway in glutamate production by two coryneform bacteria.

In amino acid production by coryneform bacteria, study on relationship between change in enzyme activities and production of a target amino acid is important. In glutamate production, Kawahara et al. discovered that the effect of decrease in 2-oxoglutamate dehydrogenase complex (ODHC) on glutamate production is essential (Kawahara et al.

Temperature and humidity control system in a lunar base.

An increasing number of lunar base construction programs are in the process of developing lunar resources such as helium 3. The objective of the present work is to evaluate the temperature and humidity control system, which will allow man to live and work on the moon while developing lunar resources. The results of thermal load calculation show that the load of electric lighting is a 80 to 90% of the cooling load in the habitat module and that only the cooling function is required for temperature control.