Role of Dentin MMPs in Caries Progression and Bond Stability

Abstract

Dentin can be described as a biological composite with collagen matrix embedded with nanosized hydroxyapatite mineral crystallites. Matrix metalloproteinases (MMPs) and cysteine cathepsins are families of endopeptidases. Enzymes of both families are present in dentin and collectively capable of degrading virtually all extracellular matrix components. This review describes these enzymes and their presence in dentin, mainly focusing on their role in dentin caries pathogenesis and loss of collagen in the adhesive hybrid layer under composite restorations. MMPs and cysteine cathepsins present in saliva, mineralized dentin, and/or dentinal fluid may affect the dentin caries process at the early phases of demineralization. Changes in collagen and noncollagenous protein structure may participate in observed decreases in mechanical properties of caries-affected dentin and reduce the ability of caries-affected dentin to remineralize. These endogenous enzymes also remain entrapped within the hybrid layer during the resin infiltration process, and the acidic bonding agents themselves (irrespective of whether they are etch-and-rinse or self-etch) can activate these endogenous protease proforms. Since resin impregnation is frequently incomplete, denuded collagen matrices associated with free water (which serves as a collagen cleavage reagent for these endogenous hydrolase enzymes) can be enzymatically disrupted, finally contributing to the degradation of the hybrid layer. There are multiple in vitro and in vivo reports showing that the longevity of the adhesive interface is increased when nonspecific enzyme-inhibiting strategies are used. Different chemicals (i.e., chlorhexidine, galardin, and benzalkonium chloride) or collagen cross-linker agents have been successfully employed as therapeutic primers in the bonding procedure. In addition, the incorporation of enzyme inhibitors (i.e., quaternary ammonium methacrylates) into the resin blends has been recently promoted. This review will describe MMP functions in caries and hybrid layer degradation and explore the potential therapeutic role of MMP inhibitors for the development of improved intervention strategies for MMP-related oral diseases.

Effects of zinc fluoride on inhibiting dentin demineralization and collagen degradation <i>in vitro</i>: A comparison of various topical fluoride agents

“…The surface was ground flat using a SiC waterproof abrasive paper of 800-1000 grit. After that, the ground surface was coated by a waterproof nail varnish leaving a window (approximately 2×2 mm 2 ) as an area for tested.…”

“…A pathogenesis study of caries lesions demonstrated this multifactorial disease to be initiated from biofilms, in which bacterial acids demineralize tooth substrate followed by collagen degradation from host-derived collagenases 2) . To inhibit the progression and promote the healing of root caries, prevention and treatment strategies should focus on inhibiting collagen degradation and promoting remineralization.…”

“…Considering the composition of dentin volume, which is approximately 50% minerals, 30% collagen, and 20% water, collagen degradation appears to significantly contribute to caries progression. The role of collagenase, particularly host matrix metalloproteinases (MMPs), has been indicated in the caries process 2,12) , whereas the MMP inhibitor prevented dentin caries in rats 13) . Another study revealed that mineral loss in dentin that was cyclically treated with acid and collagenase enzyme was greater than that of treated only with acid in vitro 14) .…”

Non-biodegradable polymer particles for drug delivery: A new technology for “bio-active” restorative materials

“…Several properties can be proposed as useful "bio-active" functions for restorative materials. One major approach involves addition of "bio-protective" effects such as control of bacterial infection 1,2) , strengthening of the tooth substrate 3,4) , prevention of demineralization 2,5) , or protection of interfacial deterioration [6][7][8] . The other approach involves conferring "bio-promoting" effects such as remineralizing effects 9,10) , control of inflammation, or promotion of tissue regeneration 11) .…”

Influence of Grape Seed Extract Solution on Microleakage Between Composite Resin and Dentin

“…The bonding material will penetrate the gap of the collagen fibers forming the hybrid layer. The bonding of composite resins to dentin is harder than their bonding to enamel due to the heterogeneous characteristics of dentin, which increase the possibility of adhesive failure [3][4][5].…”