Objective: The flexural strength (FS) and flexural modulus (Ef) of three chemical-cure (Protemp Garant 3, PerfecTemp II, Temphase) bis-acryl, one dual-cure (Luxatemp Solar) bis-acryl and a polyethyl methacrylate (Trim) provisional resin material were evaluated. Methods: Beam-shaped specimens (25mm x 2mm x 2mm) (n=20) were prepared in a metal-backed teflon split mold maintained at 37ºC ± 1ºC for a period of five minutes in order to simulate clinical conditions. An additional group (Trim P) was cured under pressure. Specimens were then removed from the split mold, stored in 37ºC distilled water and tested at 1 and 24 hours on an Instron testing machine utilizing a three-point loading jig at 1.0mm/min displacement rate. Apparent Ef were calculated from the corrected load-deflection plots. Results: Mean values for FS (MPa) and Ef (GPa) with standard deviations are listed below:
FS | Ef | |||
Resin | 1h | 24h | 1h | 24h |
Luxatemp Solar | 49.7 (4.6) | 92.7 (10.8) | 1.42 (0.1) | 2.62 (0.3) |
Integrity | 40.1 (5.4) | 92.3 (7.9) | 1.01 (0.2) | 2.94 (0.3) |
Protemp 3 | 63.8 (6.9) | 84.8 (7.3) | 1.76 (0.1) | 2.51 (0.2) |
Temphase | 40.7 (5.5) | 79.2 (9.9) | 1.27 (0.2) | 2.45 (0.2) |
PerfecTemp II | 35.7 (3.7) | 68.9 (6.6) | 1.01 (0.1) | 2.35 (0.3) |
Trim | 34.7 (2.2) | 34.7 (2.1) | 1.0 (0.1) | 1.52 (0.1) |
Trim P | 33.1 (3.0) | 31.1 (3.4) | 1.01 (0.1) | 1.41 (0.1) |
ANOVA (p<0.001) and Ryan-Einot-Gabriel-Welsch Test (p<0.05) showed significant differences between provisional resins for both FS and Ef at 1 and 24 hours. Conclusions: The initial (1hr) strength properties (FS and Ef) of Protemp 3 were significantly greater than all other resins tested. Post-gelation polymerization seems to play an important role in determining the strength properties of both chemical and dual-cure bis-acryl resins within the first 24 hours.