Some researchers report low in vitro bond strengths when testing RelyX™ Unicem Cement. What may be the cause of this?
RelyX™ Unicem cement is reliable cement in the hands of clinicians; however, skewed results can arise in the hands of those unfamiliar with testing this new class of material in-vitro. Typically when cement bond strengths are tested, teeth are prepared and a PTFE mold is placed over the tooth. The mold has a cylindrical hole cut into it. The mold is then filled with the cement and cured. This bond strength technique is fairly representative for testing bond performance with direct restorative materials, but is not clinically representative for an indirect procedure. For traditional total-etch adhesives/resin cement systems the tooth is etched followed by an application of the adhesive and cured. This leads to a surface ready to bond the cement and usually leads to acceptable bond performance. However, for RelyX Unicem cement, the tooth does not receive any pre-treatment to prepare the surface. The adhesion is dependent on the cement’s ability to wet out the tooth and penetrate into the
