Ten‐years degradation of resin–dentin bonds

Abstract

The purpose of this study was to evaluate the durability of resin-dentin bonds in 10-yr water-storage testing. Resin-dentin bonded bulk specimens were prepared using six commercially available resin adhesives. The resin-dentin bonded specimens were stored in water for 24 h (control group) or for 10 yr (experimental groups). After each storage period, the specimens were sectioned to make specimen beams and then subjected to a microtensile bond test. After the bond test, fractured surfaces were examined by scanning electron microscopy (SEM). In addition, interfacial observation of silver nanoleakage was performed using the backscatter electron mode of SEM. The bond strengths of four of the six adhesive systems tested decreased significantly after 10 yr. However, no significant bond-strength reduction was recorded for the other two systems. The interfacial observations showed water tree propagation in the bonding resin layer as a typical morphological change after aging for five of the six adhesives tested. Water tree propagation may be a symptom of degradation in the resin bonding layer of resin-dentin bonds.

Degradation of resin-dentin bonds of etch-and-rinse adhesive system to primary and permanent teeth

“…Even though several researches have assessed the deterioration of resindentin bonds in permanent teeth, information re- garding their bonding stability to primary dentin is still limited. 15,[18][19][20] In fact, degradation of resin-dentin bonds was observed in the current study, represented by a decrease in µTBS values after 6 months of water storage, as observed in previous studies. 20,21 However, the reduction in bond strength was more pronounced for permanent dentin.…”

“…While greater density of the tubules and larger diameter 1 result in a reduced area of intertubular dentin available for bonding, the lower mineral content 2 reduce the buffering capacity and increase the reactivity of primary dentin to acidic solutions, resulting in the formation of thicker hybrid layers compared with permanent teeth. 3,4 Prolonged etching time tend to produce deeper dentin demineralization, 5 and subsequently, a nonimpregnated area along the bottom of the hybrid layer that containing exposed collagen fibrils, more prone to undergo enzymatic 14 and hydrolytic [15][16][17] degradation over time. Even though several researches have assessed the deterioration of resindentin bonds in permanent teeth, information re- garding their bonding stability to primary dentin is still limited.…”

MMP Inhibitors on Dentin Stability

“…Typically, bond strength decreases after 100 days or 6 months of aging, although not down to zero, as an amount of bond strength is retained even after water storage for a long time (Hashimoto et al, 2010). This decrease in bond strength is related to a hydrolysis of collagen matrix of the hybrid layer combined with the degradation of the hydrophilic polymers of the adhesive systems (Manso et al, 2009).…”

Ten-year observation of dentin bonding durability of 4-META/MMA-TBB resin cement —a SEM and TEM study

“…Several studies have examined longer periods of storage time, of 5 or 7 y 5,16) . It is possible that a new degradation phase of resin-dentin bonds might be observed under longer storage periods than those used in previous studies 17) . Therefore, the results of the current study can be regarded as long-term findings about a currently available product.…”

“…The unprotected collagen fibrils at the hybrid layer undergo degradation marked by disarrangement of collagen web, widening the interfibrillar space, and the thinning diameter of collagen fibrils when exposed to water for several months 31) . On the loss of collagen fibrils at the hybrid layer, it has also been suggested that activation of host-derived matrix metalloproteinase (MMP) within the dentin matrix at the interface may be responsible for the degradation 17,32) . In short, the null hypothesis in this study was rejected, as differences in bond durability of SB to dentin over 10 y was clearly observed.…”