Impact of adhesive system generation and light curing units on orthodontic bonding: In vitro study

Area of Science:

• Dental Materials Science
• Orthodontic Adhesion
• Biomaterials Engineering

Background:

• Adhesive systems are crucial for orthodontic bracket bonding.
• Evaluating the performance of different generation adhesive systems is essential for clinical success.
• Light curing unit intensity can influence bond strength.

Purpose of the Study:

• To compare the adhesive performance of fourth, fifth, and seventh generation adhesive systems (GASs).
• To assess the impact of two different light curing unit intensities on shear bond strength (SBS).

Main Methods:

• 120 extracted human premolars were divided into four groups.
• Groups utilized fourth, fifth, and seventh generation adhesive systems.
• Seventh generation groups were tested with light curing units of 1500 mw/cm² and 800 mw/cm².
• Shear bond strength (SBS) and Adhesive Remnant Index (ARI) were evaluated.

Main Results:

• Fourth and fifth GASs showed comparable SBS, both significantly higher than seventh GAS.
• The 1500 mw/cm² light curing unit resulted in higher SBS compared to the 800 mw/cm² unit.
• Seventh GAS with lower light intensity exhibited the weakest bond strength and highest bracket debonding rates.

Conclusions:

• Fourth and fifth generation adhesive systems offer superior bond strength over seventh generation systems.
• Higher intensity light curing units (1500 mw/cm²) significantly improve orthodontic bracket adhesion.
• Optimal energy for enhanced adhesion was achieved with 1500 mw/cm² light curing for 30 seconds.