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158 rev port estomatol med dent cir maxilofac. 2019;60(4):155-162

Figure 1. Experimental design for surface free energy (n=7).
[CHX – chlorhexidine]

200-E, Aralab, Cascais, Portugal), in order to simulate a 3-month specific conditioner was applied to the area and let dry for 30
44
aging process inside the oral cavity. The surfaces of the den- seconds, as recommended by the manufacturer. Then, the
ture base specimens were finished to a 3-mm thickness in a freshly mixed reline resin was placed on the bonding area.
2
rotational grinding and polishing machine (DAP-U, Struers, After polymerization, five sticks with a section of 1 mm were
Denmark) with a 600-grit silicon carbide paper (Carbimet Paper obtained from each specimen, using an Isomet cutting machine
Discs, Buehler Ltd., Lake Bluff, IL). Their thickness was con- 1000 Precision Saw (Serial No. 666-IPS-03518; Buehler, Lake Bluff,
firmed using a digital micrometer (Mitutoyo Digimatic, MFG. IL, USA), under constant water refrigeration. The sticks were
Co., Ltd. Tokyo, Japan) with ± 0.01-mm precision. identified, submitted to an aging process in artificial saliva by
Afterward, the relining procedure was performed. The sur- previously described methods, and tested. The μTBS test was
face of the Probase Hot was previously conditioned according performed with a universal testing machine (Instron model
to the reline resin used. For Kooliner and Probase Cold, the 4502, Instron Ltd., Bucks, HP 12 3SY, England) using a 1 kN load
bonding area was scrubbed once with a microbrush soaked cell and a 1 mm/min crosshead speed, until fracture (Figure 2).
with the correspondent monomer. In Ufi Gel Hard groups, a The failure mode was assessed by two calibrated observers with

Figure 2. Experimental design for microtensile bond strength (n=6).
[CHX – chlorhexidine]