Method for Immediate Measurement of In Vitro Bond Strength of Bonded Direct Esthetic Restorations

Abstract

There are many different ways to measure the bond strength of direct esthetic restorations to various dental substrates. Unfortunately, most methods cannot measure bond strengths immediately after a restoration has been placed. This lack of clinically-relevant information seriously affects the clinician's ability to select and use various bonding agents and procedures. The aim of this article is to provide a very detailed method for immediate measurement of in vitro bond strengths of direct bonded esthetic restorations. It focuses on the steps that o should be taken to select and prepare various tooth substrates for bond strength testing, the steps to "restore" various tooth substrates, and to measure the immediate in vitro bond strength. A fundamental understanding of o a standardized testing protocol should provide clinicians with a clearer appreciation of bond strengths associated with various bonding procedures.

Immediate and 24-Hour Bond Strengths of Two Dental Adhesive Systems to Three Tooth Substrates

“…15 Three human tooth substrates were mounted in acrylic as previously reported ( Figure 1). 16,17 The first substrate was clean, unprepared enamel. Relatively flat coronal areas of central and lateral incisors were cleaned with a pumice flour slurry and rubber cup for 5 seconds and rinsed for 5 seconds.…”

“…These specimens were prepared using a model trimmer with coarse and fine silicon carbide wheels and rinsed for 5 seconds. 16 Specimens were cleaned with a pumice flour slurry and rubber cup for 5 seconds and rinsed with an air/ water syringe for 5 seconds. The embedding mold used for this method is made of polycarbonate and does not stick to methylmethacrylate resins.…”

“…Because of the surface irregularities of the unprepared specimens, a slightly different embedding procedure was required as noted in the previous report ( Figure 2). 16 For the OptiBond Solo™ plus specimens, 37.5% phosphoric acid gel (Kerr Gel Etchant, sds Kerr, USA ) was applied and agitated for 15 seconds and rinsed with an air/water syringe for 5 seconds. Excess water was removed by gentle air drying for 1 second.…”

“…Specimens for immediate bond strength testing were placed in an Instron machine according to the previously reported method within 1 minute of light-initiation. 16 Specimens for 24-hour bond strength testing were stored in distilled water until testing. The Instron crosshead speed was 0.5mm/min (Figure 3).…”