Substantivity of Carbodiimide Inhibition on Dentinal Enzyme Activity over Time.

Area of Science:

• Biomaterials Science
• Dental Materials Science
• Biochemistry

Background:

• Collagen degradation in the hybrid layer compromises resin-dentin bond durability.
• Endogenous enzymatic activities within the hybrid layer contribute to this degradation.
• 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide HCl (EDC) is investigated for its potential to inhibit these enzymes.

Purpose of the Study:

• To evaluate the effect of a 0.3 M EDC-containing conditioner on endogenous enzymatic activities within the hybrid layer (HL) after one year.
• To assess the impact of EDC on HL created by both self-etch and etch-and-rinse dental adhesives.
• To determine if EDC pretreatment can improve long-term resin-dentin bond durability by reducing enzymatic degradation.

Main Methods:

• Dentin specimens were bonded using Clearfil SE Bond (self-etch) or XP Bond (etch-and-rinse) adhesives.
• Pretreatment involved applying 0.3 M EDC for 1 minute to the HL before adhesive application.
• In situ zymography and confocal laser scanning microscopy were used to quantify gelatinolytic activity in the HL after 24 hours and 1-year storage in artificial saliva.

Main Results:

• Enzymatic activity was detected in the HLs of both adhesives after 24 hours, with XP Bond showing higher activity than Clearfil SE Bond.
• EDC pretreatment significantly reduced enzymatic activity compared to controls at both time points.
• After one year, enzymatic activities increased in non-EDC treated groups, while EDC-treated groups maintained significantly lower activity.

Conclusions:

• EDC pretreatment effectively reduces, but does not completely inhibit, matrix-bound collagenolytic enzyme activities in the hybrid layer over one year.
• This EDC application is beneficial for both self-etch and etch-and-rinse adhesive systems.
• EDC shows promise in enhancing the long-term durability of resin-dentin bonds by mitigating enzymatic degradation.