The evolution of adhesive dentistry: From etch-and-rinse to universal bonding systems.

Objectives: This review aimed at presenting the mechanisms and pitfalls of adhesion to enamel and dentin, advances in the materials science and in the development of strategies to improve hybrid layer (HL) longevity.

Methods: Search of the literature was performed on PubMed, Scopus and Web of Science with keywords related to the structure of the dental substrate, HL degradation mechanisms and strategies to contrast them.

Results: Albeit the advances in the dental materials' properties, HL degradation is still a relevant and current issue in adhesive dentistry.

Current approaches to produce durable biomaterials: Trends in polymeric materials for restorative dentistry applications.

Dental caries continues to be a public health issue, especially more evident in underserved populations throughout the U.S. Unfortunately, especially with an aging population, hundreds of thousands of resin composite restorations are replaced each year due to recurring decay and fracture.

A novel low shrinkage dimethacrylate monomer as an alternative to BisGMA for adhesive and resin-based composite applications.

The aim of this study was to develop a mixture of dimethacrylate isomers (PG6EMA) as a potential monomer for dental adhesives and composites. PG6EMA was synthesized de novo and characterized in the presence of ethanol (3%, 6% or 9%). BisGMA/TEGDMA (BTEG, 50/50 wt.

Improving Self-Healing Dental-Restorative Materials with Functionalized and Reinforced Microcapsules.

Dental resin composites are widely used in clinical settings but often face longevity issues due to the development and accumulation of microcracks, which eventually lead to larger cracks and restoration failure. The incorporation of microcapsules into these resins has been explored to introduce self-healing capability, potentially extending the lifespan of the restorations. This study aims to enhance the performance of self-healing dental resins by optimizing the microcapsules-resin matrix physicochemical interactions.

Stability of the Dentin-Bonded Interface Using Self-Etching Adhesive Containing Diacrylamide after Bacterial Challenge.

Acrylamides are hydrolytically stable at pH lower than 2, and were shown to preserve bonded interface integrity with two-step, total etch adhesives. The objective of this study was to leverage those two characteristics in self-etching primers containing the acidic monomer 10-MDP and test the microtensile bond strength before and after incubation with incubation. Acidic primers (10 wt % 10-methacryloyloxydecyl dihydrogen phosphate─10-MDP; 45 wt % ,-diethyl-1,3-bis(acrylamido)propane─DEBAAP, or 2-hydroxyethyl methacrylate─HEMA; 45 wt %, glycerol-dimethacrylate─GDMA) and adhesives (DEBAAP or HEMA/10-MDP/UDMA 45/10/45 wt %) were made polymerizable by the addition of 0.

Engineered nanofibrillar collagen with tunable biophysical properties for myogenic, endothelial, and osteogenic cell guidance.

A goal of regenerative engineering is the rational design of materials to restore the structure-function relationships that drive reparative programs in damaged tissues. Despite the widespread use of extracellular matrices for engineering tissues, their application has been limited by a narrow range of tunable features. The primary objective of this study is to develop a versatile platform for evaluating tissue-specific cellular interactions using Type I collagen scaffolds with highly tunable biophysical properties.

Multi-acrylamides improve bond stability through collagen reinforcement under physiological conditions.

Objectives: Acrylamides were shown to significantly improve bonding stability in adhesive restorations, but the reinforcement mechanism has not been fully elucidated. We tested the hypothesis that hydrogen bonding reinforcement of the collagen network (with secondary or tertiary acrylamides), as well as degree of crosslinking of the polymer network (with di- or tri-functional acrylamides), can be two of the factors at play.

Methods: Two-step total etch adhesives comprising UDMA (60 wt%) and 40 wt% of: TAAEA, TMAAEA (secondary, tertiary tri-acrylamides), BAAP, DEBAAP (secondary, tertiary di-acrylamides) or HEMA (mono-methacrylate - control) were formulated.

Revisiting gas-chromatography/mass-spectrometry molar response factors for quantitative analysis (FID or TIC) of glycosidic linkages in polysaccharides produced by oral bacterial biofilms.

Methylation analysis was performed on methylated alditol acetate standards and Streptococcus mutans extracellular polymeric substances (EPS) produced from wild-type and Gtf knockout strains (∆GtfB, ∆GtfB, and ∆GtfD). The methylated alditol acetate standards were representative of glycosidic linkages found in S. mutans EPS and were used to calibrate the GC-MS system for an FID detector and MS (TIC) and produce molar response factor, a necessary step in quantitative analysis.

Microbiome imaging goes à la carte: Incorporating click chemistry into the fluorescence-activating and absorption-shifting tag (FAST) imaging platform.

The human microbiome is predominantly composed of facultative and obligate anaerobic bacteria that live in hypoxic/anoxic polymicrobial biofilm communities. Given the oxidative sensitivity of large fractions of the human microbiota, green fluorescent protein (GFP) and related genetically-encoded fluorophores only offer limited utility for live cell imaging due the oxygen requirement for chromophore maturation. Consequently, new fluorescent imaging modalities are needed to study polymicrobial interactions and microbiome-host interactions within anaerobic environments.

Influence of bioactive particles and onium salt on the physicochemical properties of experimental infiltrants.

This study evaluated physicochemical properties of experimental infiltrants after addition of hydroxyapatite nanoparticles (HAp) or 58S bioactive glass (BAG) and diphenyliodonium hexafluorophosphate (DPI). The resin matrix was composed of TEGDMA/Bis-EMA (3:1), 0.5 mol% CQ, and 1 mol% EDAB.

The potential use of glycosyl-transferase inhibitors for targeted reduction of S. mutans biofilms in dental materials.

Streptococcus mutans is the primary oral caries-forming bacteria, adept at producing "sticky" biofilms via the synthesis of insoluble extracellular polysaccharides (EPS), catalyzed by glucosyltransferases (GTFs). To circumvent the use of broad-spectrum antibiotics to combat these bacteria, this study sought to modify existing EPS-targeting small molecules with the ultimate goal of producing anti-biofilm polymer surfaces specifically targeting S. mutans.

Compositional boundaries for functional dental composites containing calcium orthophosphate particles.

Objectives: To investigate the interrelationships among handling, degree of conversion (DC), mechanical behavior and Ca release of composites containing dicalcium phosphate dihydrate (DCPD, CaHPO.2HO), as a function of total inorganic content and DCPD: glass ratio.

Methods: Twenty-one formulations (1 BisGMA: 1 TEGDMA, in mols) with inorganic fractions ranging from zero to 50 vol% and different DCPD: glass ratios were evaluated for viscosity (parallel plate rheometer, n = 3), DC (near-FTIR spectroscopy, n = 3), fracture toughness/K (single-edge notched beam, n = 7-11) and 14-day Ca release (inductively coupled plasma optical emission spectroscopy, n = 3).

Thiol Quantification Using Colorimetric Thiol-Disulfide Exchange in Nonaqueous Solvents.

A careful analysis of two (thiol-disulfide exchange) thiol quantification chromophores' behavior (Ellman's reagent and Aldrithiol-4) in nonaqueous solvents is presented. A wide range of kinetic profiles and response factors were measured to exhibit a large variance for nonaqueous systems. We report several robust benchtop and room-temperature methods using different organic solvents compared to aqueous conditions.

Engineering a new generation of thermoset self-healing polymers based on intrinsic approaches.

Objectives: The development of thermosetting polymers with autonomic reparability has become an important research topic since it has the potential to benefit several fields such as biomaterials, tissue engineering, paint and coating technologies, electronics, and soft robotics. In dentistry, the development of restorative materials capable of inhibiting the propagation of microcracks caused by masticatory forces and thermal stress may represent a crucial expansion of the limited clinical lifespan of dental restorations, which is a pressing challenge. Biological systems have inspired the underlying concepts and designs of synthetic polymeric self-healing systems, and different strategies have been used to impart autonomous repair capability in polymers.

Strategies to design extrinsic stimuli-responsive dental polymers capable of autorepairing.

Objectives: For many years, the requirements for dental polymers were limited to inertially filling the cavity and restoring form, function, and esthetics. Inorganic filler systems were widely enhanced to maximize the mechanical properties and optimize finishing and polishing procedures. The development of alternative photoinitiator systems also improved the carbon-carbon double bond conversion, increasing biocompatibility, wear, and stain resistance.

Dentin primer based on a highly functionalized gelatin-methacryloyl hydrogel.

Unlabelled: Gelatin-methacryloyl hydrogels (GelMA) have demonstrated their utility as scaffolds in a variety of tissue engineering applications.

Objectives: In this study, a highly functionalized GelMA hydrogel was synthesized and assessed for degree of functionalization. As the proposed GelMA hydrogel was coupled to a visible-light photoinitiator, we hypothesized it might serve as base to formulate a model dentin primer for application in restorative dentistry.

"Fatigue-Crack Propagation Behavior in Microcapsule-Containing Self-Healing Polymeric Networks".

Over the last years, research on the design of dental self-healing polymers has grown dramatically. It is related to the promising potential of maximizing the clinical lifespan of dental restorations that this strategy holds. In this manuscript, the microcapsule-based strategy is innovated by incorporating the high toughness component N,-Dimethylacrylamide (DMAM) into the healing agent systems and analyzing in-depth the change in crack propagation behavior induced by the addition of microcapsules into the highly crosslinked polymeric network.

Physical-chemical characterization and bond strength to zirconia of dental adhesives with different monomer mixtures and photoinitiator systems light-activated with poly and monowave devices.

Bonding to crystalline zirconia is currently a challenge. Properly cured adhesives are crucial to optimize this bond, and that in turn is influenced by the initial mobility of the system, as well as by the reactivity of the initiators. This study aimed to characterize adhesives containing monomer mixtures of different viscosities and double and triple photoinitiator systems; and to evaluate the bonding to Y-TZP zirconia, when adhesives were light-activated with monowave or polywave light-curing units (LCU).

Improper Light Curing of Bulkfill Composite Drives Surface Changes and Increases Biofilm Growth as a Pathway for Higher Risk of Recurrent Caries around Restorations.

How dentists cure a resin-based material has deleterious effects on the material's properties and its interaction with surrounding dental tissues. Biofilm accumulation has been implicated in the pathogenesis of carious lesions around dental restorations, with its composition manifesting expressed dysbiosis in patients suffering from dental caries. To evaluate the influence of varying radiant exposure on the degree of conversion (DC%), biofilm growth, and surface roughness of bulk-fill composites under different light-curing conditions.

Improvement on properties of experimental resin cements containing an iodonium salt cured under challenging polymerization conditions.

Objective: The use of resin cements in clinical practice entails photopolymerization through prosthetic devices, which precludes light penetration. The objective of this study was to modify experimental resin cements (ERCs) with diphenyliodonium hexafluorophosphate (DPI) in an attempt to improve chemical and mechanical properties of materials cured with reduced irradiance and final radiant exposure.

Methods: A co-monomer base containing a 1:1 mass ratio of 2.

Toughening and polymerization stress control in composites using thiourethane-treated fillers.

Filler particle functionalization with thiourethane oligomers has been shown to increase fracture toughness and decrease polymerization stress in dental composites, though the mechanism is poorly understood. The aim of this study was to systematically characterize the effect of the type of filler surface functionalization on the physicochemical properties of experimental resin composites containing fillers of different size and volume fraction. Barium glass fillers (1, 3 and 10 µm) were functionalized with 2 wt% thiourethane-silane (TU-Sil) synthesized de novo and characterized by thermogravimetric analysis.

Effect of side-group methylation on the performance of methacrylamides and methacrylates for dentin hybridization.

Unlabelled: The stability of the bond between polymeric adhesives to mineralized substrates is crucial in many biomedical applications. The objective of this study was to determine the effect of methyl substitution at the α- and β-carbons on the kinetics of polymerization, monomer hydrolytic stability, and long-term bond strength to dentin for methacrylamide- and methacrylate-based crosslinked networks for dental adhesive applications.

Methods: Secondary methacrylamides (α-CH substituted=1-methyl HEMAM, β-CH substituted=2-methyl HEMAM, and unsubstituted=HEMAM) and OH-terminated methacrylates (α- and β-CH mixture=1-methyl HEMA and 2-methyl HEMA, and unsubstituted=HEMA) were copolymerized with urethane dimethacrylate.