Localization of MMP-2, MMP-9, TIMP-1, and TIMP-2 in human coronal dentine.

Objectives: Matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) play important roles in dentine formation, caries progression and hybrid layer degradation. This study tested the hypothesis that the distribution and concentrations of MMP-2, MMP-9, TIMP-1 and TIMP-2 are different at different depths of human coronal dentine, including odontoblasts.

Methods: Protein localization was performed using immunohistochemistry.

MMP-2 assay within the hybrid layer created by a two-step etch-and-rinse adhesive: biochemical and immunohistochemical analysis.

Objective: Degradation of hybrid layers (HLs) within resin-infiltrated dentine results from multiple degradation factors, including collagenolytic activity of specific matrix metalloproteinases (MMPs). Inhibition of host-derived MMPs may, therefore, slow the degradation of HL. The null hypothesis tested is that the presence of MMP-2 is similar regardless of chlorhexidine (CHX) pre-treatment or the use of an adhesive.

Setting properties and cytotoxicity evaluation of a premixed bioceramic root canal sealer.

Introduction: This study investigated the setting time and micohardness of a premixed calcium phosphate silicate-based sealer (EndoSequence BC Sealer; Brasseler USA, Savannah, GA) in the presence of different moisture contents (0-9 wt%). The moisture content that produced the most optimal setting properties was used to prepare set EndoSequence BC Sealer for cytotoxicity comparison with an epoxy resin-based sealer (AH Plus; Dentsply Caulk, Milford, DE).

Methods: Standardized disks were created with BC Sealer, AH Plus, Pulp Canal Sealer EWT (positive control) (SybronEndo, Orange CA), and Teflon (Small Parts Inc.

A hybrid approach to direct pulp capping by using emdogain with a capping material.

Introduction: This study evaluated the formation of reparative hard tissues in baboon pulps after Emdogain (EMD) application in conjunction with 3 pulp-capping materials.

Methods: Thirty-two premolars in four 3-year-old baboons were randomly assigned to 1 of 3 pulp-capping materials. A split-mouth design and intra-animal side randomization were applied to 3 experimental groups (calcium hydroxide, ProRoot White mineral trioxide aggregate, white Portland cement) and the control group (no pulp-capping material).

New method of measuring water permeability of adhesive resin films.

Purpose: To adapt a simple gravimetric method to measuring the permeability of adhesive resin films to liquid water, and to compare this to the water vapor permeability of the same resins.

Methods: Using commercially-available permeability cups designed for industrial permeability testing, the loss of mass of water vapor or liquid water from a stainless steel cup sealed with a resin film was measured over 1-2 days. The permeabilities of Parafilm (control), Clearfil SE Bond adhesive, Xeno IV and One-Up Bond F were compared.

Resin-dentin bonds to EDTA-treated vs. acid-etched dentin using ethanol wet-bonding. Part II: Effects of mechanical cycling load on microtensile bond strengths.

Objective: To compare microtensile bond strengths (MTBS) subsequent to load cycling of resin bonded acid-etched or EDTA-treated dentin using a modified ethanol wet-bonding technique.

Methods: Flat dentin surfaces were obtained from extracted human molars and conditioned using 37% H(3)PO(4) (PA) (15s) or 0.1M EDTA (60s).

Histologic evaluation of canal and isthmus debridement efficacies of two different irrigant delivery techniques in a closed system.

Introduction: This study compared canal and isthmus debridement efficacies between side-vented needle irrigation (SNI) and continuous ultrasonic irrigation (CUI) in the mesial root of mandibular first molars with narrow isthmuses using a closed-canal design.

Methods: Micro-computed tomography scanning was used to select 20 teeth, each containing a narrow isthmus. Each root was sealed at the apex; embedded in polyvinylsiloxane to simulate a closed-canal system; and instrumented to size 40, 0.

Histomorphometric and micro-computed tomography analysis of pulpal response to three different pulp capping materials.

Introduction: This study evaluated the responses of baboon dental pulps after the application of 3 pulp capping materials.

Methods: Thirty premolar teeth in four 3-year old baboons were randomly assigned to 1 of 3 pulp capping materials. A split-mouth design was used, and intra-animal side randomization was applied to the 3 experimental groups (calcium hydroxide, ProRoot white mineral trioxide aggregate, white Portland cement) and the control group (no pulp capping material).

The use of sodium trimetaphosphate as a biomimetic analog of matrix phosphoproteins for remineralization of artificial caries-like dentin.

Objectives: This study examined the use of sodium trimetaphosphate (STMP) as a biomimetic analog of matrix phosphoproteins for remineralization of artificial carious-affected dentin.

Methods: Artificial carious lesions with lesion depths of 300±30μm were created by pH-cycling. 2.

Antiglioma effects of combined use of a baculovirual vector expressing wild-type p53 and sodium butyrate.

Background: Combination therapy is usually desirable for successful cancer treatment, especially in cancers that are resistant to single forms of therapy.

Methods: To achieve an optimal therapeutic effect against glioblastoma, we tested a strategy that combines baculovirus-mediated transfer of the p53 tumor suppressor gene with the use of sodium butyrate, a histone deacetylase inhibitor. This strategy was designed based on the findings that the transduction efficiency of baculovirus in mammalian cells can be markedly enhanced by the addition of histone deacetylase inhibitors and that these inhibitors are effective in inducing cell cycle arrest, differentiation, or apoptosis in tumor cells.

Cysteine cathepsins in human carious dentin.

Matrix metalloproteinases (MMPs) are important in dentinal caries, and analysis of recent data demonstrates the presence of other collagen-degrading enzymes, cysteine cathepsins, in human dentin. This study aimed to examine the presence, source, and activity of cysteine cathepsins in human caries. Cathepsin B was detected with immunostaining.

Effect of dentin etching and chlorhexidine application on metalloproteinase-mediated collagen degradation.

Dentin matrix metalloproteinases (MMPs) are involved in the degradation of collagen in resin-dentin interfaces. This study evaluated whether collagen degradation can be prevented by chlorhexidine digluconate (CHX) after different dentin demineralization procedures. The demineralization of human dentin was performed with phosphoric acid (PA), EDTA or acidic monomers (Clearfil SE Bond and Xeno V).

Apical surgery: endoscopic findings at the resection level of 168 consecutively treated roots.

Aim: Endoscopic evaluation of the cut root face after root-end resection during apical surgery.

Methodology: Consecutive cases undergoing apical surgery from June 2006 to May 2008 were enrolled. After root-end resection, the cut root face was inspected with a rigid endoscope and the following findings were assessed: number of canals, presence of isthmus, presence and location of craze lines/cracks, frosted dentine, and gaps between root filling material and dentine.

Limitations in bonding to dentin and experimental strategies to prevent bond degradation.

The limited durability of resin-dentin bonds severely compromises the lifetime of tooth-colored restorations. Bond degradation occurs via hydrolysis of suboptimally polymerized hydrophilic resin components and degradation of water-rich, resin-sparse collagen matrices by matrix metalloproteinases (MMPs) and cysteine cathepsins. This review examined data generated over the past three years on five experimental strategies developed by different research groups for extending the longevity of resin-dentin bonds.

Immunohistochemical and biochemical assay of MMP-3 in human dentine.

Objective: The function of endogenous MMP-3 and its distribution within the human dentine is unclear. Thus, the aim of the present study was to assay the presence and distribution of MMP-3 within human sound dentine by means of biochemical and immunohistochemical assays.

Methods: Powdered dentine from extracted human teeth was prepared and (1) partially demineralised with 1% H(3)PO(4) for 10min or (2) untreated (control).

The critical barrier to progress in dentine bonding with the etch-and-rinse technique.

Objectives: The lack of durability in resin-dentine bonds led to the use of chlorhexidine as MMP-inhibitor to prevent the degradation of hybrid layers. Biomimetic remineralisation is a concept-proven approach in preventing the degradation of resin-dentine bonds. The purpose of this study is to examine the integrity of aged resin-dentine interfaces created with a nanofiller-containing etch-and-rinse adhesive after the application of these two approaches.

The inhibitory effects of quaternary ammonium methacrylates on soluble and matrix-bound MMPs.

Matrix metalloproteinases (MMPs) bound to dentin contribute to the progressive degradation of collagen fibrils in hybrid layers created by dentin adhesives. This study evaluated the MMP-inhibiting potential of quaternary ammonium methacrylates (QAMs), with soluble rhMMP-9 and a matrix-bound endogenous MMP model. Six different QAMs were initially screened by a rhMMP-9 colorimetric assay.

Effect of surface preparation on bond strength of resin luting cements to dentin.

This study examined the effects of using two different burs for dentin surface preparation on the microtensile bond strength (microTBS) of three resin luting cements. Flat, deep dentin surfaces from 45 extracted human third molars were divided into three groups (n = 15) according to bur type: (i) diamond bur and (ii) tungsten carbide bur. The controls were abraded with #600-grit SiC paper.

The effect of QMix, an experimental antibacterial root canal irrigant, on removal of canal wall smear layer and debris.

Introduction: This study examined the ability of two versions of QMix, an experimental antimicrobial irrigant, on removal of canal wall smear layers and debris using an open canal design.

Methods: Cleaned and shaped single-rooted human root canals were irrigated with NaOCl as the initial irrigant and one of the following as the final irrigant: (1) QMix I (pH = 8), (2) QMix II (pH = 7.5), (3) distilled water, (4) 17% EDTA, and (5) BioPure MTAD (Dentsply Tulsa Dental Specialties, Tulsa, OK).

State of the art etch-and-rinse adhesives.

Objectives: The aim of this study was to explore the therapeutic opportunities of each step of 3-step etch-and-rinse adhesives.

Methods: Etch-and-rinse adhesive systems are the oldest of the multi-generation evolution of resin bonding systems. In the 3-step version, they involve acid-etching, priming and application of a separate adhesive.

Differences between top-down and bottom-up approaches in mineralizing thick, partially demineralized collagen scaffolds.

Biominerals exhibit complex hierarchical structures derived from bottom-up self-assembly mechanisms. Type I collagen serves as the building block for mineralized tissues such as bone and dentin. In the present study, 250-300 μm thick, partially demineralized collagen scaffolds exhibiting a gradient of demineralization from the base to surface were mineralized using a classical top-down approach and a non-classical bottom-up approach.

Zinc reduces collagen degradation in demineralized human dentin explants.

Objectives: Dentin matrix metalloproteinases are implicated in the pathogenesis of caries and contribute to collagen degradation in resin-dentin interfaces. The objective was to determine if collagen degradation may be modulated by an excess of zinc or zinc chelators.

Methods: Mineralized and phosphoric acid demineralized human dentin specimens were tested.

Hierarchical and non-hierarchical mineralisation of collagen.

Biomineralisation of collagen involves functional motifs incorporated in extracellular matrix protein molecules to accomplish the objectives of stabilising amorphous calcium phosphate into nanoprecursors and directing the nucleation and growth of apatite within collagen fibrils. Here we report the use of small inorganic polyphosphate molecules to template hierarchical intrafibrillar apatite assembly in reconstituted collagen in the presence of polyacrylic acid to sequester calcium and phosphate into transient amorphous nanophases. The use of polyphosphate without a sequestration analogue resulted only in randomly-oriented extrafibrillar precipitations along the fibrillar surface.

[Allergen specific immunotherapy: new approaches].

Specific immunotherapy (SIT) is the only disease-modifying and causal treatment of IgE mediated allergic diseases. Soon this treatment will turn 100 years old. Subcutaneous immunotherapy is still considered to be the gold standard of SIT.