Page 166 - Clinical relevance of current materials for cranial implants

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Chapter 8
RESULTS
In this in vitro study, different fabrication methods and compositions of PMMA-based materials were compared to determine if they release different amounts of residual monomers over time and if the release patterns of these residual monomers are different.
High-performance liquid chromatography (HPLC)
The results of the leachable residual monomers are summarized in Table 2 and fits of pseudo first order kinetics curves for the leaching process are graphically depicted in Figure 1. Corresponding non-linear regression variables are presented in Table 3.
NextDent C&B MFH does not appear to release monomers past the first time point (1 hour), whereas Vertex Self-Curing, Palacos R+G, and DePuy CMW-3 do release monomers over a longer period. NextDent C&B MFH released more residual monomers in the first hour compared to the other materials, indicating that all monomers in this material that can leach out do so in the first hour, whereas this takes more time for the other materials. This is confirmed in the pseudo first order kinetics model where NextDent C&B MFH has a doubling time of 0.59 hours, however the release profile does not follow a pseudo first order kinetics profile (R2 = 0.13). After 48 hours all materials surpassed the cumulative release of NextDent C&B MFH. The doubling time of Vertex Self-Curing and DePuy CMW-3 are similar at around 8 hours, Palacos R+G is higher at approximately 13 hours, however this is not a significant difference.
Cummulative Monomer Release
Vertex Self-Curing 100 Palacos R+G
50
01 10 100 Time[h]
Released monomer [μg/g]
Figure 1: Cumulative residual monomer release during 2 weeks incubation in water at 37 °C with fitted pseudo first order kinetics curves.
NextDent C&B MFH DePuy CMW-3