http://webdelprofesor.ula.ve/odontologia/robertramirez/PDF/1.pdf

State of the art of self-etch adhesives

http://webdelprofesor.ula.ve/odontologia/robertramirez/PDF/2.pdf

State of the art etch-and-rinse adhesives

Relationship between bond-strength tests and clinical outcomes

Research on matrix metalloproteinases (MMPs) and in particular on gelatinase B, alias MMP-9, has grown exponentially in the decade 2003–2012. Structural details about flexibility of MMP-9 monomers, together with glycosylation, oligomerization, heterogeneity and instability of the wildtype enzyme explain why crystallography experiments have not yet been successful for the intact enzyme. MMP-9 may be viewed as a multidomain enzyme in which the hemopexin, the O-glycosylated and the catalytic domains yield support for attachment, articulation and catalysis, respectively. The stepwise proteolytic activation of the inactive zymogen into a catalytically active form becomes gradually better understood. Priming of activation by MMP-3 may be executed by meprins that destabilize the interaction of the aminoterminus with the third fibronectin repeat. Alternatively, autocatalytic activation may occur in the presence of molecules that tightly bind to the catalytic site and that push the cystein residue in the p...

Biochemistry and molecular biology of gelatinase B or matrix metalloproteinase-9 (MMP-9): The next decade

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 They include: (1) increasing the degree of conversion and esterase resistance of hydrophilic adhesives; (2) the use of broad-spectrum inhibitors of collagenolytic enzymes, including novel inhibitor functional groups grafted to methacrylate resins monomers to produce anti-MMP adhesives; (3) the use of cross-linking agents for silencing the activities of MMP and cathepsins that irreversibly alter the 3-D structures of their catalytic/allosteric domains; (4) ethanol wet-bonding with hydrophobic resins to completely replace water from the extrafibrillar and intrafibrillar collagen compartments and immobilize the collagenolytic enzymes; and (5) biomimetic remineralization of the water-filled collagen matrix using analogs of matrix proteins to progressively replace water with intrafibrillar and extrafibrillar apatites to exclude exogenous collagenolytic enzymes and fossilize endogenous collagenolytic enzymes A combination of several of these strategies should result in overcoming the critical barriers to progress currently encountered in dentin bonding

Limitations in Bonding to Dentin and Experimental Strategies to Prevent Bond Degradation

Improved dental adhesive technology has extensively influenced modern concepts in restorative dentistry In light of minimal-invasive dentistry, this new approach promotes a more conservative cavity design, which basically relies on the effectiveness of current enamel-dentine adhesives Nowadays, the interaction of adhesives with the dental substrate is based on two different strategies, commonly described as an etch-and-rinse and a self-etch approach In an attempt to simplify the bonding technique, manufacturers have decreased the number of steps necessary for the accomplishment of the bonding procedure As a consequence, two-step etch-and-rinse and one-step (self-etch) adhesives were introduced and gained rapid popularity in the dental market due to their claimed user-friendliness and lower technique sensitivity However, many concerns have been raised on the bonding effectiveness of these simplified adhesives, especially in terms of durability, although this tends to be very material dependent In order to blend all the adhesive components into one single solution, one-step adhesives were made more acidic and hydrophilic Unfortunately, these properties induce a wide variety of seemingly unrelated problems that may jeopardize the effectiveness and stability of adhesion to the dental substrate Being more susceptible to water sorption and thus nanoleakage, these adhesives are more prone to bond degradation and tend to fail prematurely as compared to their multi-step counterparts Incidentally, another factor that may interfere with the bonding effectiveness of adhesives is the technique used for caries removal and cavity preparation Several tools are on the market today to effectively remove carious tissue, thereby respecting the current trend of minimum intervention Despite their promising performance, such techniques modify the tooth substrate in different aspects, possibly affecting bonding effectiveness Altogether, we may conclude that not only the adhesive formulation, but also substrate nature must be taken into account to achieve a stable bonding interface, rendering the restorative treatment more predictable in terms of clinical performance In this review, we analyse the current theoretical and clinical aspects of adhesion to enamel and dentine, and discuss the diverse possibilities to overcome problems which nowadays still challenge clinicians in their achievement of a more stable and effective bond to tooth enamel and dentine

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1834-7819.2011.01294.x

Current aspects on bonding effectiveness and stability in adhesive dentistry

Bonding effectiveness of a new ‘multi-mode’ adhesive to enamel and dentine

Adhesive procedures activate dentin-associated matrix metalloproteinases (MMPs), and so iatrogenically initiate bond degradation. We hypothesized that adding MMP inhibitors to adhesive primers may prevent this endogenous enzymatic degradation, thereby improving bond durability. A non-specific MMP inhibitor (chlorhexidine) and a MMP-2/9-specific inhibitor (SB-3CT) were admixed to the primers of an etch & rinse and a self-etch adhesive, both considered as gold-standard adhesives within their respective categories. For dentin powder exposed to the adhesives under clinical application conditions, gelatin zymography revealed the release of MMP-2 (not of MMP-9) by the etch & rinse adhesive, while no release of enzymes could be detected for the mild self-etch adhesive, most likely because of its limited dentin demineralization effect. The built-in MMP inhibitors appeared effective in reducing bond degradation only for the etch & rinse adhesive, and not for the self-etch adhesive. Water sorption of adhesive interfaces most likely remains the principal mechanism of bond degradation, while endogenous enzymes appear to contribute to bond degradation of only etch & rinse adhesives.

Atsushi Mine

Papers

State of the art of self-etch adhesives

Relationship between bond-strength tests and clinical outcomes

Current aspects on bonding effectiveness and stability in adhesive dentistry

Bonding effectiveness of a new ‘multi-mode’ adhesive to enamel and dentine

Inhibition of Enzymatic Degradation of Adhesive-Dentin Interfaces