Introduction:

Several variations of universal adhesives are available on the market, each with a unique curing method. However, it is unknown how application modes affect the adhesives’ functionality.

Objectives:

The aim of the study was to compare the impact of ultrasonic agitation on micro-shear bond strength (μSBS) of a self-cure universal adhesive system to enamel versus a light-cure universal adhesive system at different storage times.

Material and methods:

Based on the treatment mode (ultrasonic and manual), 48 specimens were divided into 2 major groups. Every major group was allocated to two sub-groups according to universal adhesive system: light-cure and self-cure. Then, every sub-group was evenly split according to storage times (3 and 6 months). After placing a specially designed silicon sheet above the occlusal surface and applying these 2 adhesive systems as per the manufacturer (manual group) or agitating the material with an ultrasonic device for 20 sec (ultrasonic group), the composite was inserted in sheet holes. µSBS was assessed after two water storage intervals (3 and 6 months) using a universal testing device.

Results:

Compared with manual treatment, ultrasonic agitation demonstrated a statistically significantly greater μSBS values for the tested adhesives. There were no significant differences between the 2 types of adhesive systems and storage times. However, the light-cure adhesive showed an insignificantly higher μSBS value compared with self-cure adhesive, and all adhesives’ μSBSs decreased insignificantly with aging.

Conclusions:

Ultrasonic agitation can be considered as an efficient method for enhancing the enamel µSBS of both light-cure and self-cure universal adhesive systems.