In-situ photo-crosslinkable elastomer based on polyalphaolefin/halloysite nanohybrid.

In this research, new injectable and in situ photocurable elastomeric nanohybrids have been fabricated from polyalphaolefin (PAO) resins and halloysite nanofiller. In this regard, the co-oligomerization of long α-olefin monomers (C6, C8 and C10) with alkenol counterparts was carried out via a simple cationic route to provide OH-functionalized PAOs. The newly formed PAO type copolymer resins as well as halloysite nanoclay were then equipped with photocurable CC bonds containing an acrylate moiety.

Effect of bioactive glass-containing dentin adhesives on microshear bond strength of composite restorations.

Background: In general, bioactive glasses (BAGs) can react with tissue minerals and promote remineralization. However, the application of BAG in bonding agents and its impact on bond strength remain uncertain due to insufficient information and limited research in this area.

Materials And Methods: This study employed a randomized controlled design to assess the effects of composite-bonding agents with varying BAG contents on shear bond strength and fracture pattern in sound and demineralized teeth, with and without thermocycling.

Synthesis, characterization, photo-polymerization, hydrolytic stability, and etching behavior of new self-etch adhesive monomers.

Considering the poor hydrolytic stability of the most methacrylate-based functional monomers of self-etch dental adhesives in acidic and aqueous conditions, in this study allyl-based photo-polymerizable self-etch monomers was synthesized in order to improve the hydrolytic stability. The new self-etch monomers based on phosphonic acid functional groups were synthesized through a two-step procedure. First, phosphoric anhydride, poly-phosphoric acid, and polyethylene glycol were reacted to produce phosphate ester precursor (P-PEG-P).

Solution photo-copolymerization of acrylic acid and itaconic acid: The effect of polymerization parameters on mechanical properties of glass ionomer cements.

Objective: To synthesize a series of poly (acrylic acid-co-itaconic acid) (P(AA-co-IA)) copolymers with different molecular weights (MWs) through a facile water-based solution photopolymerization and to investigate the operational and mechanical properties of the experimental glass-ionomer (GI) cements made of the ionomers.

Methods: Thioglycolic acid (TGA) was used as a chain transfer agent to synthesize P(AA-co-IA) ionomers with different MWs through the solution photopolymerization. The chemical structure, MWs, and rheological properties of the copolymers were fully characterized.

Effect of Application of a Bio-Adhesive on the Removal Torque Value and Rotational Misfit at the Implant-Abutment Junction: An In Vitro Study.

The aim of this study was to assess the effect of application of a recently developed bio-adhesive (Impladhesive) to abutment screw threads on the removal torque value and rotational misfit at the implant-abutment junction. This in vitro study evaluated 20 implant fixtures and 20 straight abutments. Specimens were randomly divided into two groups ( = 10) with/without adhesive application.

Effect of zinc oxide nanoparticles on physical and antimicrobial properties of resin-modified glass ionomer cement.

Background: To improve the limitations, many modifications in the resin-modified glass ionomer (RMGI) composition have been proposed. In this study, we evaluated the effect of different concentrations of zinc oxide (ZnO) nanoparticles incorporated into RMGI cement on its physical and antimicrobial properties.

Materials And Methods: In this study, ZnO nanoparticles with 0-4 wt.

Modified POSS nano-structures as novel co-initiator-crosslinker: Synthesis and characterization.

Objective: To synthesize an amine-modified polyhedral oligomeric silsesquioxane (POSS) nano-structure as a novel co-initiator-crosslinker (co-Ini-Linker) and to determine the effect of the co-Ini-linker on the physical and mechanical behavior of an experimental dental composite.

Methods: The amine-methacrylate POSS nano-structures (AMA-POSS) were chemically synthesized by anchoring a tertiary amine functionality on the methacrylate POSS (MA-POSS) branches. Three types of AMA-POSS, having different amine branches in their structures, were synthesized through the Aza Michael reaction.

On the properties of nanosilicate-based filled dental adhesives: Synthesis, characterization, and optimized formulation.

Objective: In this study, we incorporated hybrid nanoparticles (poly (acrylic acid)-grafted nanoclay/nanosilica, respectively, with platelet and spherical morphologies, abbreviated as PAA-g-NC-Sil) in different concentrations (0, 0.2, 0.5, 1, 2 and 5 wt%) to an experimental dentin bonding system and investigated the physical properties of the filled adhesive and its shear bond strength (μ-SBS) to dentin.

Poly(hydroxybutyrate--hydroxyvalerate) Porous Matrices from Thermally Induced Phase Separation.

Thermally induced phase separation followed by freeze drying has been used to prepare biodegradable and biocompatible scaffolds with interconnected 3D microporous structures from poly(hydroxybutyrate--hydroxyvalerate) (PHBV) copolymers containing 5 and 12 wt % of 3-hydroxyvalerate (HV). Solutions of PHBV in 1,4-dioxane, underwent phase separation by cooling under two different thermal gradients (at -25 °C and -5 °C). The cloud point and crystallization temperature of the polymer solutions were determined by turbidimetry and differential scanning calorimetry, respectively.

Synthesis and characterization of core-shell nanoparticles and their application in dental resins.

The aim of this study was to synthesize acrylic core-shell particles and silica-loaded core-shell hybrid particles through emulsion polymerization. Also this work examined the influence of synthesized nanoparticles loading in a Bis-GMA/TEGDMA resin matrix on some mechanical properties of the dental composite resins. Core-shell particles consisting of polybutyl acrylate (PBA) rubbery core and polymethyl methacrylate (PMMA)/polystyrene (PS) shell were synthesized by seeded emulsion polymerization.

Dual modified nanosilica particles as reinforcing fillers for dental adhesives: Synthesis, characterization, and properties.

A facile procedure has been devised to develop a novel dentin bonding system containing poly (acrylic acid)-grafted-silanized fumed silica particles as reinforcing filler, with high stability of nanoparticle dispersion and enhanced bond strength and mechanical properties. In the first step, the silanization of fumed silica nanoparticles was performed in the following conditions: (i) ethanol-water solution with a pH of 5 and (ii) cyclohexane with a pH of 9 using trimethoxysilylpropyl methacrylate (γ-MPS) as a reactive silane coupling agent. FTIR and TGA analyses confirmed the presence of silane in the resultant structure and enhanced dispersion stability of modified particles was proved by a separation analyzer and also zeta potential analyses.

Poly (methacrylic acid) modified spherical and platelet hybrid nanoparticles as reinforcing fillers for dentin bonding systems: Synthesis and properties.

Objective: In this study the mechanical and adhesion properties of an experimental methacrylate based dentin bonding system containing a combination of spherical and layered platelet nanoparticles were investigated. The nanoparticles were first modified through surface graft polymerization of methacrylic acid in order to make the particles surface compatible with the bonding matrix resin.

Materials And Methods: Graft free radical polymerization in aqueous media was performed to attach Poly (methacrylic acid) (PMA) chains onto the surface of Na-MMT nanoclay (Cloisite® Na+) and silica nanoparticles (Aerosil® 200).

Synthesis of poly(acrylic-co-itaconic acid) through precipitation photopolymerization for glass-ionomer cements: Characterization and properties of the cements.

Objective: The aim of this study was to synthesize poly(acrylic acid-co-itaconic acid) (PAA-co-PIA) ionomer through a novel precipitation photopolymerization technique. The ionomer was characterized and the effect of its structural parameters, such as molecular weight and copolymer composition were investigated on the mechanical properties of glass-ionomer prepared using the ionomer.

Methods: Design of experiment (DOE) was used to examine the effect of monomer ratio and the amount of chain transfer agent on the molecular weight and final conversion of the ionomers synthesized through the precipitation photopolymerization.

Synthesis of plate-like β-tricalcium phosphate nanoparticles and their efficiency in remineralization of incipient enamel caries.

The purpose of this study was to synthesize nano-sized β-tricalcium phosphate (nano-TCP) particles and determine its concentration-dependent properties on incipient enamel caries lesions. Nano-TCP was synthesized as a wet chemical through a method using low concentration of precursors and low addition rate of calcium nitrate tetrahydrate as a second phase. Morphology and phase composition of the particles were analyzed by SEM, XRD, and EDXA techniques.

A novel thymol-doped enamel bonding system: Physico-mechanical properties, bonding strength, and biological activity.

Purpose: Over the past decades, the preparation of antibacterial restorative dental adhesives has obtained increasing attention in order to prevent secondary caries. In the present study, a novel essential oil-based antibacterial resin adhesive was prepared and evaluated for dental applications. In this regards, thymol, which is a major phenolic component of thyme essential oil, was incorporated into methacrylate resin matrix and its effect on the physico-mechanical and biological properties of the experimental bonding agent was investigated.

The Effect of Calcium Hydroxide and Nano-calcium Hydroxide on Microhardness and Superficial Chemical Structure of Root Canal Dentin: An Ex Vivo Study.

Introduction: Calcium hydroxide (CH) and nano-calcium hydroxide (NCH) as intracanal medicaments may affect the physical and chemical properties of dentin. The aim of this investigation was to evaluate the effects of CH and NCH on the microhardness and superficial chemical structure of radicular dentin.

Methods: In this in vitro trial, 80 dentin discs were randomly assigned into 2 control and 2 treatment groups (n = 20).

The Effect of Incorporation of 0.5 %wt. Silica Nanoparticles on the Micro Shear Bond Strength of a Resin Modified Glass Ionomer Cement.

Statement Of The Problem: The clinical success of glass ionomer restorations depends on the strength of resin-modified glass ionomer (RMGI) cement bonding to dentin and there is limited information available regarding the bond strength of resin modified glass ionomers containing silica nanoparticles to dental structures.

Purpose: The aim of this study was to compare the microshear bond strength (µSBS) of RMGI with and without silica (SiO2) nanoparticles to dentin of permanent teeth.

Materials And Method: In this experimental study, the occlusal surfaces of 30 freshly extracted intact third molars were ground to expose the flat dentin and after conditioning with 20% poly acrylic acid, were randomly assigned to two main groups (n=15).

Effect of rinsing time and surface contamination on the bond strength of silorane-based and dimethacrylate-based composites to enamel.

Background: The aim of this study was to assess whether saliva contamination and rinsing time for 15, 30, and 60 seconds, affects the shear bond strength of silorane and methacrylate-based composites to enamel.

Material And Methods: Two light cure resin, P60 (3M ESPE) and Filtek LS Silorane were tested. 120 sound premolars were randomly divided into four groups of 30 teeth based on composite type with or without saliva contamination after etching and rinsing.

PMMA/double-modified organoclay nanocomposites as fillers for denture base materials with improved mechanical properties.

The aim of this study was to investigate the effect of double-modified organoclay on mechanical properties of polymethylmethacrylate (PMMA) denture base resins. An organoclay was further modified via a silanization process using 3-trimethoxysilylpropyl methacrylate (MPS) as a reactive silane coupling agent. X-ray diffraction patterns (XRD), thermogravimetric analysis (TGA), and Fourier-transform infrared spectroscopy (FTIR) confirmed the presence of MPS in the resulting double-modified nanoclay structure.

Structure-properties relationships in dental adhesives: Effect of initiator, matrix monomer structure, and nano-filler incorporation.

Objectives: This is a confirmatory study to evaluate the effect of photoinitiator type and concentration, matrix monomer chemical structure, and nanoparticle incorporation on the physical and mechanical properties of an experimental dentin bonding agent.

Materials And Methods: Different concentrations of camphorquinone-amine (CQ-A) system, butanedione (BD), and phenylpropanedione (PPD), as photoinitiator, BTDMA, as a comonomer containing carboxylic acid groups, and silica nanoparticles as reinforcing inorganic filler were incorporated into a methacrylate base experimental dental adhesive. The effect of these ingredients, as independent variables, on the shrinkage kinetics, flexural strength and modulus, and microshear bond strength of the adhesives were then investigated.

Effects of ethanol concentrations of acrylate-based dental adhesives on microtensile composite-dentin bond strength and hybrid layer structure of a 10 wt% polyhedral oligomeric silsesquioxane (POSS)-incorporated bonding agent.

Background: The aim of this study was to assess for the first time the effects of different amounts of ethanol solvent on the microtensile bond strength of composite bonded to dentin using a polyhedral oligomeric silsesquioxane (POSS)-incorporated adhesive.

Materials And Methods: This experimental study was performed on 120 specimens divided into six groups (in accordance with the ISO TR11405 standard requiring at least 15 specimens per group). Occlusal dentin of thirty human molar teeth was exposed by removing its enamel.

Correction to: Compositional design and Taguchi optimization of hardness properties in silicone-based ocular lenses.

The original version of this article unfortunately contained a mistake: The spelling of the Ebrahim Gafar-Zadehs' name was incorrect. The corrected name is given above.

Casein phosphopeptide- amorphous calcium phosphate effects on brackets shear bond strength and enamel damage.

Background: The aim of study was to evaluate the application of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and fluoride regarding their effect on the shear bond strength (SBS), bond failure pattern of brackets using the adhesive remnant index (ARI) and assessing the quality of enamel surface using the enamel damage index (EDI).

Material And Methods: Sixty extracted premolar teeth were randomly divided into four groups regarding pretreatment application of CPP-ACP and fluoride. Brackets were bonded using the conventional method.

In vivo study of antifungal effects of low-molecular-weight chitosan against Candida albicans.

This study investigated the antifungal effects of low-molecular-weight chitosan solution on Candida albicans in denture stomatitis in comparison with nystatin suspension. This randomized, sing-leblind clinical trial included 40 patients diagnosed with denture stomatitis. Patients were divided into two groups, wherein one was treated with chitosan and the other with nystatin for 2 weeks.

Dentin bonding agent with improved bond strength to dentin through incorporation of sepiolite nanoparticles.

Background: The study aims to investigate the effect of incorporation of sepiolite nanoparticles on the microtensile bond strength of an experimental dentin bonding to the human dentin.

Material And Methods: The sepiolite nanoparticles were incorporated into an experimental methacrylate-based dentin bonding system in concentrations of 0.0, 0.