Effect of Polymerization Accelerator on Bond Strength to Eugenol-Contaminated Dentin

Area of Science:

• Dental Materials Science
• Adhesive Dentistry
• Polymer Chemistry

Background:

• Eugenol contamination in dentin can compromise the microtensile bond strength (µTBS) of dental adhesives.
• Traditional bonding protocols may be insufficient to overcome the inhibitory effects of eugenol.
• Investigating methods to enhance bond durability in the presence of contaminants is critical for clinical success.

Purpose of the Study:

• To evaluate the efficacy of a polymerization accelerator in improving the µTBS of etch-and-rinse and self-etch adhesives to eugenol-contaminated dentin.
• To compare the performance of a three-step etch-and-rinse adhesive (OptiBond FL) versus a two-step self-etch adhesive (Clearfil SE Bond) under eugenol contamination.

Main Methods:

• Human molar dentin specimens were divided into eugenol-contaminated (restored with zinc oxide eugenol cement) and control groups.
• Specimens were treated with a polymerization accelerator (p-toluenesulfinic acid sodium salt; Accel) for varying durations (0, 10, or 30 seconds).
• Bonding was performed using OptiBond FL or Clearfil SE Bond, followed by composite restoration and µTBS testing after 24-h water storage.

Main Results:

• Eugenol-contaminated dentin exhibited significantly lower µTBS compared to control dentin for both adhesive types.
• The application of the polymerization accelerator (Accel) significantly increased the compromised µTBS on eugenol-contaminated dentin.
• OptiBond FL demonstrated significantly higher µTBS to eugenol-contaminated dentin than Clearfil SE Bond.

Conclusions:

• The use of a polymerization accelerator effectively enhances the microtensile bond strength of both etch-and-rinse and self-etch adhesives to eugenol-contaminated dentin.
• This approach offers a viable strategy to improve the reliability of dental restorations when eugenol contamination is a concern.