Tooth bleaching effects 
on the adhesive interface 
of composite restorations

Area of Science:

• Dental Materials Science
• Restorative Dentistry
• Biomaterials

Background:

• Tooth bleaching is a common cosmetic procedure.
• Concerns exist regarding potential damage to the tooth-restoration interface of composite fillings.
• Evaluating the impact of different bleaching agents and activation methods is crucial for clinical practice.

Purpose of the Study:

• To assess the effects of various dental bleaching techniques on the integrity of the tooth-restoration interface in composite restorations.
• To investigate microleakage and enamel hardness adjacent to composite restorations after different bleaching protocols.

Main Methods:

• Bovine incisor fragments with composite restorations were subjected to five groups: control, at-home bleaching (10% hydrogen peroxide), in-office bleaching (35% hydrogen peroxide), LED-activated bleaching, and laser-activated bleaching.
• Samples underwent thermocycling and silver nitrate immersion for microleakage assessment.
• Other samples were pH cycled and analyzed for enamel Knoop hardness near the adhesive interface.

Main Results:

• No statistically significant differences in microleakage were observed between the control and all tested bleaching groups.
• Knoop hardness measurements of the enamel adjacent to the adhesive interface showed no significant changes in the bleached groups compared to the control.

Conclusions:

• Current tooth bleaching techniques, including those using hydrogen peroxide with different activation methods, do not compromise the tooth-restoration interface of composite restorations.
• The integrity of composite restorations is maintained following common dental bleaching procedures.