Ethanol Wet-bonding Challenges Current Anti-degradation Strategy

Abstract

The long-term effectiveness of chlorhexidine as a matrix metalloproteinase (MMP) inhibitor may be compromised when water is incompletely removed during dentin bonding. This study challenged this anti-bond degradation strategy by testing the null hypothesis that wet-bonding with water or ethanol has no effect on the effectiveness of chlorhexidine in preventing hybrid layer degradation over an 18-month period. Acid-etched dentin was bonded under pulpal pressure simulation with Scotchbond MP and Single Bond 2, with water wet-bonding or with a hydrophobic adhesive with ethanol wetbonding, with or without pre-treatment with chlorhexidine diacetate (CHD). Resin-dentin beams were prepared for bond strength and TEM evaluation after 24 hrs and after aging in artificial saliva for 9 and 18 mos. Bonds made to ethanol-saturated dentin did not change over time with preservation of hybrid layer integrity. Bonds made to CHD pretreated acid-etched dentin with commercial adhesives with water wet-bonding were preserved after 9 mos but not after 18 mos, with severe hybrid layer degradation. The results led to rejection of the null hypothesis and highlight the concept of biomimetic water replacement from the collagen intrafibrillar compartments as the ultimate goal in extending the longevity of resin-dentin bonds.

Bonding efficiency and durability: current possibilities

“…216 This technique also prevents phase separation of hydrophobic resin monomers in the presence of water, 217,218,219 since the latter is completely replaced by ethanol prior to the application of the ethanolsoluble monomers. 220,221 Additionally, the elimination of residual water seems to contribute to decrease or even eliminate hydrolytic enzymatic degradation of collagen fibrils, 212,222 thereby increasing bond durability and stability. 213 However, this technique is very sensitive, time consuming and requires the application of many steps to achieve the desired dehydration, which becomes inappropriate.…”

Long-term bond strength of a self-adhesive resin cement to intraradicular dentin pretreated with chlorhexidine and ethanol

“…In this regard, ethanol has been proposed as a substitute for water in dentin bonding 12,17 . The concept of replacing water with ethanol infers the possibility that hydrophobic monomers are capable of encapsulating the collagen fibrils in an effective and enduring manner 22 . Given that the bond strength of the resin cement is highest in the cervical region and lowest in the apical region, probably due to reduced light penetration into the latter scenario, this leads to a strict polymerization of the material 6 .…”

Effects of light curing modes and ethanol-wet bonding on dentin bonding properties

“…With continuing in-depth research on the adhesive properties and the increase in people's aesthetic requirements, improving the quality and durability of the bonding interface has become an urgent problem in dentin bonding (Sadek et al, 2010;Guimarães et al, 2012;Li et al, 2012). Although the two-step total-etch technique can achieve high bond strength, there are problems of high technical sensitivity, uncontrollable interface moisture and poor durability.…”