Early Phase Enamel Bond Performance of a Two-step Adhesive Containing a Primer Derived from a Universal Adhesive

PURPOSE

To investigate the changes in the enamel bond performance of a two-step adhesive containing a primer derived from a universal adhesive in the early phase before 24 h and compare them to those of other adhesives. The Knoop hardness number (KHN) of the cured adhesive layers and resin composite was measured.

MATERIALS AND METHODS

A new two-step adhesive using universal adhesive technology, G2-Bond Universal, was tested. Two conventional two-step adhesives, Clearfil SE Bond 2 and OptiBond eXTRa, and an established universal adhesive, Scotchbond Universal Plus Adhesive, were used as comparison materials. Twelve specimens per group were used to measure the shear bond strength (SBS) to bovine enamel in different etching modes. The bonded specimens were stored in distilled water at 37°C for 5 min or 1, 6, 12, or 24 h before SBS testing. The KHN of the adhesive layer and resin composite was determined after the same storage periods as for SBS testing.

RESULTS

All adhesives exhibited increased SBS with prolonged storage periods, irrespective of the etching mode. The KHN of the adhesive layer and resin composite increased over time.

CONCLUSIONS

There were strong positive correlations between the SBS and KHN of the adhesive layer and resin composite. Phosphoric acid pre-etching of enamel effectively increases enamel bond performance. The two-step adhesive G2-Bond Universal demonstrated significantly higher bond strength in the early phase than the other adhesives in self-etch mode.

Influence of application method on surface free-energy and bond strength of universal adhesive systems to enamel

The aim of the present study was to determine the influence of different adhesive application methods and etching modes on enamel bond effectiveness of universal adhesives using shear bond strength (SBS) testing and surface free-energy (SFE) measurements. The adhesives Scotchbond Universal, All-Bond Universal, Adhese Universal, and G-Premio Bond were used. Prepared bovine enamel specimens were divided into four groups, based on type of adhesive, and subjected to the following surface treatments: (i) total-etch mode with active application; (ii) total-etch mode with inactive application; (iii) self-etch mode with active application; and (iv) self-etch mode with inactive application. Bonded specimens were subjected to SBS testing. The SFE of the enamel surfaces with adhesive was measured after rinsing with acetone and water. The SBS values in total-etch mode were significantly higher than those in self-etch mode. In total-etch mode, significantly lower SBS values were observed with active application compared with inactive application; in contrast, in self-etch mode there were no significant differences in SBS between active and inactive applications. A reduction in total SFE was observed for active application compared with inactive application. The interaction between etching mode and application method was statistically significant, and the application method significantly affected enamel bond strength in total-etch mode.

Comparative evaluation of the enamel bond strength of 'etch-and-rinse' and 'all-in-one' bonding agents on cut and uncut enamel surfaces

AIMS AND OBJECTIVES

To compare tensile bond strength of an 'etch-and-rinse' bonding agent (Single bond,3M ESPE, MN, USA) with an 'all-in-one' bonding agent (iBond, Heraeus Kulzer, NY, USA) on cut and uncut enamel surfaces. The null hypothesis tested is that the 'all-in-one' bonding agent matches the 'etch-and-rinse' bonding agent in terms of tensile bond strength to enamel.

MATERIALS AND METHODS

Forty extracted human mandibular teeth were used for the study. Twenty teeth with intact enamel surfaces were divided into two groups of 10 teeth each. The enamel surfaces of the 20 teeth were prepared and assigned to two more groups of 10 teeth each. One group each of intact and prepared enamel surfaces were used to bond with the 'etch-and-rinse' bonding agent [Single bond (SB), 3M ESPE, MN, USA] and the other two groups one each of intact and prepared enamel surfaces were used to bond with the 'all-in-one' bonding agent [ iBond (IB), Heraeus Kulzer, NY, USA]. The tensile bond strength was measured on the universal testing machine (Unitek, 9450 PC, FIE, INDIA) at a cross head speed of 1 mm / minute.

RESULTS

The results were statistically analyzed using a one-way ANOVA and student 't' test. The values for the 'etch-and-rinse' bonding agent SB were significantly higher for both the cut and uncut surfaces, compared to the 'all-in-one' bonding agent IB (P < 0.05). The all-in-one bonding agent resulted in a higher bond strength on the cut enamel surfaces.

CONCLUSIONS

Based on the results, it is advisable to use the 'etch-and-rinse system' in a clinical situation requiring bonding on enamel alone.