Objectives : In this study the addition of polymerization promoters to experimental self-etching primers on the bond stability of two-step adhesives to dentin was investigated.
Materials and methods : A model self-etching primer composed of phosphate acidic monomers, HEMA, ethanol and water was obtained. The polymerization promoters added to the primer were: none (control), camphorquinone (CQ), thioquixantone (QTX), diphenyliodonium hexafluorphosphate (DPIHPP), thiobarbituric acid derivative (TBAD) or sulfinic acid derivative (SAD). The bonding resin was composed of Bis-GMA, TEGDMA, HEMA, camphorquinone and amine. Microtensile bond strength testing to bovine dentin was carried out after 24 h or one-year storage in sodium azide solution, at 37 °C. Failure modes were classified under magnification (500×).
|Polymerization promoter||24 h||One-year|
|Means (SD) for bond strength (MPa)|
|None||73.3 (15.2) A,ab||40.3 (11.0) B,a|
|CQ||70.8 (15.5) A,b||52.1 (11.4) B,a|
|QTX||74.6 (17.2) A,ab||42.0 (12.5) B,a|
|DPIHPP||84.3 (19.4) A,a||37.6 (10.5) B,a|
|TBAD||66.2 (13.5) A,b||40.8 (15.2) B,a|
|SAD||73.3 (15.7) A,ab||44.3 (15.6) B,a|