Triacrylamide-Based Adhesives Stabilize Bonds in Physiologic Conditions.

Area of Science:

• Biomaterials Science
• Dental Materials Science
• Polymer Chemistry

Background:

• Dental composite restorations are prone to degradation under physiological challenges.
• Polymerization stress and bond degradation impact restoration longevity.
• Novel adhesive and composite formulations are needed to enhance stability.

Purpose of the Study:

• To evaluate the stability of a novel acrylamide-based adhesive and thiourethane-modified composite.
• To assess the impact of mechanical and bacterial challenges on restoration integrity.
• To compare the performance of a triacrylamide (TMAAEA) adhesive against a control (HEMA).

Main Methods:

• Formulation of a 2-step total-etch adhesive system using urethane dimethacrylate with TMAAEA or HEMA.
• Development of methacrylate-based composites with thiourethane oligomers.
• Restoration of human molars, followed by storage in water or Streptococcus mutans biofilm.
• Testing under static (incubator) and dynamic (bioreactor) conditions with SEM and CLSM analysis.
• Microtensile bond strength testing before and after storage.

Main Results:

• Acrylamide-based adhesives showed more efficient initial bonding with smaller gap formation.
• The TMAAEA adhesive maintained smaller gaps under static and dynamic conditions in water.
• The acrylamide/thiourethane combination demonstrated significantly lower gap formation in the bioreactor with biofilm.
• TMAAEA-based adhesives retained initial bond strength after 7-day biofilm challenge, unlike HEMA-based adhesives.

Conclusions:

• A stable multiacrylamide-based adhesive preserves the resin-dentin interface under physiologically relevant challenges.
• The combination of acrylamide adhesive and thiourethane composite offers improved bond stability.
• Future research should explore multispecies biofilm models for more comprehensive testing.