title: Indirect Restoration Thickness and Time after Light-Activation Effects on Degree of Conversion of Resin Cement.
abstract: This study evaluated the effects of indirect restorative materials, curing conditions and time on the degree of conversion (DC) of a dual-cured resin cement using infrared spectroscopy. The resin cement (RelyX Unicem 2, 3M ESPE) was applied to the diamond surface of a horizontal attenuated-total-reflectance unit and activated using one of following conditions: self-cure, direct light exposure, light exposure through indirect restorative materials (resin nano-ceramic: Lava Ultimate, 3M ESPE or feldspathic ceramic: Vita Blocks Mark II, Vita Zahnfabrik). Four thicknesses (0.5, 1.0, 1.5 or 2.0 mm) of each indirect material were analyzed, and the light-activation was performed using a blue LED light. Data (n=5) were analyzed by three-way ANOVA, Tukey's post hoc and Dunnett's tests (α=5%). No significant differences in DC were observed between indirect materials of similar thickness. All groups exhibited higher DC after 10 min than after 5 min. At both times points, the self-cure group exhibited significantly lower DC than all the light exposure groups. Only when the overlying indirect restoration had a thickness of 2 mm did DC decrease significantly. The presence of a thick, indirect restoration can decrease the DC of resin cement. DC after 10 min was higher than after 5 min. The self-cure mode yielded lower DC than the light-activating one.
authors: Department of Restorative Dentistry, Piracicaba Dental School, Universidade Estadual Paulista, Piracicaba, SP, BR.
authors: Ana Paula Almeida
authors: AP
authors: Ayres
authors: Department of Restorative Dentistry, Piracicaba Dental School, Universidade Estadual Paulista, Piracicaba, SP, BR.
authors: Carolina Bosso
authors: CB
authors: Andre
authors: Department of Restorative Dentistry, Piracicaba Dental School, Universidade Estadual Paulista, Piracicaba, SP, BR.
authors: Rafael Rocha
authors: RR
authors: Pacheco
authors: Department of Restorative Dentistry, Piracicaba Dental School, Universidade Estadual Paulista, Piracicaba, SP, BR.
authors: Adriana Oliveira
authors: AO
authors: Carvalho
authors: Department of Restorative Dentistry, Piracicaba Dental School, Universidade Estadual Paulista, Piracicaba, SP, BR.
authors: Renata Cantanhede
authors: RC
authors: Bacelar-Sá
authors: Department of Oral Rehabilitation, College of Dental Medicine, Georgia Regents University, Augusta, GA, US.
authors: Frederick Allen
authors: FA
authors: Rueggeberg
authors: Department of Restorative Dentistry, Piracicaba Dental School, Universidade Estadual Paulista, Piracicaba, SP, BR.
authors: Marcelo
authors: M
authors: Giannini
mesh_terms: D008027:Light; D019279:Resin Cements / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D019279:Resin Cements