Influence of solvent evaporation on ultimate tensile strength of contemporary dental adhesives

• Published in: Applied adhesion science 2019-06, Vol.7 (1), p.1-11, Article 4
• Main Authors: Kameyama, Atsushi, Haruyama, Akiko, Abo, Hirokazu, Kojima, Masashi, Nakazawa, Yuichi, Muramatsu, Takashi
• Format: Article
• Language: English
• Subjects: Adhesion tests; Adhesive strength; Adhesives; Biomaterials; Bottles; Chemistry and Materials Science; Desiccants; Drying ovens; Evaporation; Materials Science; Mechanical Engineering; Silica gel; Silicon dioxide; Solvents; Submerging; Surfaces and Interfaces; Tensile strength; Thin Films; Ultimate tensile strength
• ISSN: 2196-4351; 2196-4351
• DOI: 10.1186/s40563-019-0120-0

The aim of this study was to evaluate the influence of solvent evaporation on the ultimate tensile strength (UTS) of commercial adhesives. Two 1-step (OptiBond All-In-One and G-Premio Bond) and two 2-step (Clearfil SE Protect, OptiBond XTR) adhesives were selected. Two bottles of each adhesive were opened and stored at 37 °C in a dry oven with silica gel shielded from light for 2 weeks (“Desiccated”). Two unopened bottles were stored at room temperature (“Original”). After 2 weeks, the adhesives were used to fill an hour-glass shaped, metallic matrix mold and light-cured. Samples were weighed, and then immersed in a 37 °C water bath for 1 h or 7 days. The UTS of each sample was then measured at a cross-head speed of 1 mm/min ( n  = 10). The UTS for the Clearfil SE Protect was higher in the “Original” than “Desiccated” samples ( p   0.05). Neither of the two “Original” 1-step samples could be hardened, even after light-curing, yet the ‘Desiccated’ OptiBond All-In-One samples obtained high UTS values. Both OptiBond All-In-One and Clearfil SE Protect had an increase in weight after the 7-day immersion in water. In conclusion, residual solvent reduces the mechanical strength of the adhesive. The hydrophilicity of the adhesive resin might also affect its mechanical strength.