Physical Properties of XeraCem™

As verification that a dental cement formulation is suitable for testing on human subjects a number of in vitro physical and mechanical properties should be verified. Objectives: To test an experimental cement XeraCem™, regarding Compressive strength (CS), Film thickness (FT) and net setting time (ST). Materials and Methods: CS was measured according to a slightly modified ISO 9917:2003. The samples were not clamped while being exposed to relative humidity of >90% at 37°C for 10 minutes before being stored in phosphate buffered saline at 37°C. For the CS 4 groups were tested: Group1. XeraCem™, Group 2. RelyX™ Luting cement, Group 3. Fuji Plus, and Group 4 Rely X™ Unicem. All groups were stored for 24 hours before testing. Additionally, XeraCem™ was tested after 8 days (Group 5) and 30 days (Group 6). Only XeraCem™ was tested for ST and FT according to ISO 9917:2003. The FT was tested 2 minutes after mixing. Results: The means and standard deviations after 24 hours were expressed in MPa: Group 1= 160 ± 27, Group 2= 96 ±10, Group 3= 138 ±15, Group 4= 157±10, Group 5= 176 ±10, Group 6= 196 ± 7. A single factor ANOVA showed a significant statistical difference between Groups 1 and 2 and between Groups1 and 5 (p<0.05). No statistically significant differences were found between other groups. The FT was 15±4µm and the ST was 4.8±0.1min. Conclusion: XeraCem™ showed significantly higher CS than RelyX™ Luting Cement after 24 h. There was a significant increase in CS for XeraCem™ period at 30 days compared to the 24h value. The ST and FT values of XeraCem™ are well below the requirements of the standard. Within the limits of this study XeraCem™ is deemed suitable for testing on human subjects.This study was supported in part by Doxa Dental AB.