Evaluation of bond strength durability on bleached human dentin

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Restorative Dentistry

Background:

• Dental bleaching is a common cosmetic procedure.
• Bleaching agents may potentially affect the integrity of tooth structure and restorative materials.
• Understanding the impact of bleaching on dentin-composite bond strength is crucial for clinical success.

Purpose of the Study:

• To evaluate the effect of aging on the microtensile bond strength (μTBS) between composite resin and human dentin.
• To compare the μTBS of dentin bleached with 35% hydrogen peroxide (HP) or 10% carbamide peroxide (CP) versus untreated dentin.
• To assess the durability of the bond over time (24 hours, 6 months, 12 months).

Main Methods:

• Human third molars were divided into three groups: control, CP bleaching, and HP bleaching.
• Dentin surfaces were prepared, and teeth were subjected to bleaching protocols.
• Teeth were bonded with a dental adhesive and nanohybrid composite resin.
• Microtensile bond strength (μTBS) was tested at 24 hours, 6 months, and 12 months after storage in distilled water.

Main Results:

• At 24 hours, HP bleaching resulted in significantly lower μTBS compared to the control group.
• At 6 months, the μTBS of HP-bleached dentin was comparable to the control group.
• No statistically significant changes in μTBS over time were observed for carbamide peroxide or hydrogen peroxide treated groups.
• Only the control group showed a statistically significant decrease in μTBS after 12 months of aging.

Conclusions:

• The choice of bleaching treatment (HP or CP) does not impact the long-term durability of the bond between composite resin and dentin.
• Aging effects on bond strength are comparable across different bleaching modalities.
• Clinicians can be assured of bond durability regardless of the bleaching agent used prior to restoration.