Chlorhexidine, a Matrix Metalloproteinase Inhibitor and the Development of Secondary Caries Wall Lesions in a Microcosm Biofilm Model

Abstract

This study investigated the role of a matrix metalloproteinase (MMP) inhibitor (CHX 2%) in the development of secondary caries wall lesions in different interface conditions with small (run 1) and wider gaps (run 2). Dentin discs were restored and pretreated with or without CHX 2%. In run 1, interfaces were made with gaps of 30, 60, or 90 µm. Interfaces with composite placed directly onto the dentin were either bonded (Adper Single Bond 2) or not bonded. In run 2, interfaces were made with gaps of 100 µm, with or without adhesive on the composite side (CLEARFIL SE Bond). Interfaces were either bonded or not bonded, as in run 1. Microcosm biofilms were grown on dentin-composite samples for 14 days. Caries lesion outcomes were analyzed by transversal wavelength-independent microradiography at 3 locations: the outer surface, and the interface wall at a distance of 200 and 500 µm from the gap entrance. Linear regression analyses showed that pretreatment with MMP inhibitor did not influence progression of the wall lesion at any location (p ≥ 0.218). Interfaces with intentional gaps showed positive and significant effect on the wall lesion progression at 200 µm from the gap entrance (p ≤ 0.005). A small trend of increase in wall lesion development was observed at the 200-µm location when bonding was present on the composite side. In conclusion, the dentin pretreatment with CHX 2% was not able to slow down the development of secondary caries wall lesions in small and wide gaps in this biofilm model.

Level of knowledge about metalloproteinases in dental students close to graduate from three universities in Peruvian capital city

“…Different authors have reported that there are approximately 25 types of metalloproteinases, being the most abundant in the organism, the metalloproteinases of type 1, 3, 8 and 9. 8 , 9 , 10 On contrary, there are endogenous 11 or specific tissue inhibitors 12 , 13 called TIMPS's (tissue inhibitors of metalloproteinases) that inhibit the mechanism of action of metalloproteinases, 14 , 15 as well as nonspecific inhibitors 16 or artificial inhibitors 17 , 18 such as 2% chlorhexidine digluconate solution, EDTA (ethylenediaminetetraacetic acid) and proanthocyanidin 12 , 17 , 19 , 20 , 21 , 22 , 23 that some researchers recommend to inhibit dentin metalloproteinases and prevent collagen degradation, allowing a more stable hybrid layer that increases the chances of successful adhesion and thus a restoration with increased tensile strength. 20 , 21 These studies applied in the field of restorative dentistry demonstrate the importance for dentistry students to learn, during their professional training, the mechanism of action of metalloproteinases and their nonspecific inhibitors as conditioning agents that allow greater conservation of collagen to achieve a good marginal sealing and optimal adhesion.…”

Demineralized dentin characteristics after application of Mauli banana stem gel

“…In this mechanism, metal ions such as zinc (Zn) and Ca are bound by CHX, preventing the collagen degradation process and stopping the demineralization process. 11 However, continuous use of CHX in the long term can cause allergic reactions, have toxic effects, cause stains on teeth, and cause the resistance of microorganisms to antibiotics. 6,10,12 Therefore, it is necessary to develop other alternative materials, including herbal ingredients.…”

The Role of Duration of Chlorhexidine Gluconate 2% Application on the Shear Bond Strength of a Total Etch Bonding Agent: A Comparative Study

“…13 MMPs are enzymes present in the organic components of dentine. 14 In a mineralized state (healthy dentin), MMPs are inactive, and even so, MMPs can be activated by acids from cariogenic bacteria and/or acidic materials used in restorative procedures such as phosphoric acid and acid monomers. 14 MMPs that are already active can degrade and segment collagen in dentine into several parts which then cause a degradation effect on the hybrid layer.…”

“…14 In a mineralized state (healthy dentin), MMPs are inactive, and even so, MMPs can be activated by acids from cariogenic bacteria and/or acidic materials used in restorative procedures such as phosphoric acid and acid monomers. 14 MMPs that are already active can degrade and segment collagen in dentine into several parts which then cause a degradation effect on the hybrid layer. 15 Degradation of collagen fibers will cause the bond between collagen fibers and bonding material to decrease which can lead to reduction of the hybrid layer integrity that will reduce the bond strength of the bonding material to the dentine and result in failure of the composite restoration.…”