Comparison of four fluoride etchants in bonding between titanium and a self-curing luting agent

Area of Science:

• Materials Science
• Biomaterials Engineering
• Dental Materials

Background:

• Titanium's excellent biocompatibility and mechanical properties make it ideal for dental and orthopedic implants.
• Achieving durable resin-to-titanium bonds is crucial for the longevity of bonded prosthetics and restorations.
• Surface treatments are essential for enhancing the adhesion of resin luting agents to titanium substrates.

Purpose of the Study:

• To evaluate the effectiveness of four distinct fluoride etchants in improving resin bonding to titanium.
• To compare the shear bond strengths of different fluoride etchants before and after simulated aging (thermocycling).
• To determine the optimal fluoride etchant for enhancing the durability of resin-titanium interfaces.

Main Methods:

• Commercially pure titanium specimens were prepared using alumina air-abrasion and etched with sodium fluoride (NaF), ammonium fluoride (NH4F), sodium hydrogen fluoride (NaFHF), or ammonium hydrogen fluoride (NH4FHF).
• Specimens were primed with a phosphate primer and bonded to an acrylic rod using a tri-n-butylborane-initiated luting agent.
• Shear bond strength testing was conducted before and after 10,000 thermocycles to assess bond durability.

Main Results:

• No significant differences in pre-thermocycling shear bond strength were observed among the tested fluoride etchants.
• All groups exhibited a decrease in bond strength after thermocycling, indicating material degradation.
• Sodium hydrogen fluoride (NaFHF) and ammonium hydrogen fluoride (NH4FHF) groups showed significantly higher bond strengths post-thermocycling compared to NaF, NH4F, and the non-etched control group.
• Microscopic roughening via alumina blasting combined with NaFHF or NH4FHF etching significantly enhanced resin-to-titanium bonding durability.

Conclusions:

• Fluoride etchants, particularly NaFHF and NH4FHF, play a critical role in enhancing the long-term stability of resin bonds to titanium.
• Surface preparation involving alumina blasting and specific fluoride etching (NaFHF, NH4FHF) is recommended for durable resin-titanium adhesion in clinical applications.
• The findings provide valuable insights for selecting appropriate surface treatment protocols to improve the longevity of bonded titanium restorations.