## 6 Cooling Methods and Their Effects on PMMA Bone Cement Properties
These aim to optimize thermal behavior and maintain or improve mechanical properties. The following table (Table 4) highlights innovative approaches to reducing the thermal effects of bone cement polymerization while preserving or enhancing its mechanical properties; for instance, incorporating phase-change materials (PCMs) and pre-cooling techniques effectively lowers peak temperatures, reducing the risk of thermal necrosis. Additives such as alternative monomers and nanoparticles not only manage heat generation but also improve compressive and tensile strength. Catalyst modifications like high-purity buthoxydibutylborane (BODBB) further minimize heat-related risks while enhancing biocompatibility. Moreover, strategies such as radiopacifier inclusion and surface modifications (e.g., layered double hydroxides) enhance cement's functional properties, ensuring both clinical safety and performance. Together, these advancements reflect a multifaceted effort to improve the safety and efficacy of bone cement in medical applications [57]. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Method** & \multicolumn{2}{c}{**Strategy**} & \multicolumn{2}{c}{**Effectiveness**} & \multicolumn{2}{c}{**Considerations**} \\ \hline \multirow{4}{*}{Cooling Techniques} & - & Pre-cooling components & - & Lowers peak temperature & - & May affect cement viscosity \\  & - & Irrigation with cold & - & Extends handling time & - & Requires careful timing \\ \hline \multirow{4}{*}{Cement Modifications} & - & Adding nanoparticles & - & Reduces exothermic reaction heat & - & Alters mechanical properties \\  & - & Incorporating castor oil & & - & Affects setting time \\ \hline \multirow{4}{*}{Procedural Strategies} & - & Optimal cement mantle thickness & - & Balances mechanical support and thermal safety & - & Requires precision in application \\  & - & Vacuum mixing & & safety & - & Standardization needed \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Methods to reduce the risk of thermal necrosis. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Modification** & **Specific Change** & **Impact on Thermal Necrosis** & \multicolumn{2}{c}{**Impact on Mechanical Properties**} \\ \hline Addition of PCMs (e.g., paraffin) & - & Acts as a heat sink during polymerization & - & Reduces peak temperature values & - & May slightly alter cement’s structural integrity \\ \hline Alternative monomers (e.g., glycidyl methacrylate) & - & Replacement of methyl methacrylate & - & Lowers exothermic peak temperature & - & Maintains adequate mechanical properties \\ \hline Nanoparticle additives (e.g., magnesium oxide) & - & Incorporation into & - & Reduces polymerization & - & Enhances compressive and tensile strength \\ \hline Pre-cooling techniques & - & Cooling cement and & - & Decreases peak temperature and & - & Minimal effect on density and modulus; may increase porosity \\ \hline Castor oil incorporation & - & Use as a temperature-modifying agent & - & Lowers exothermic peak temperature & - & May reduce viscosity; affects setting time \\ \hline High-purity & - & Catalyst modification & - & Maintains polymerization & - & Enhances biocompatibility and mechanical stability \\ (BODBB) & - & Catalyst modification & - & \({}^{\circ}\)C & - & Enhances biocompatibility and mechanical stability \\ \hline Layered double hydroxides & - & Surface modification to enhance bioactivity & - & Indirectly reduces thermal necrosis by promoting bone & - & Increases osteogenic potential without compromising strength \\ \hline Radiopacifiers (e.g., tantalum carbide) & - & Added for improved visualization & - & Not directly impacting thermal necrosis & - & Enhances radiopacity and mechanical stability \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Different approaches to reducing the thermal effects of bone cement polymerization without compromising its mechanical properties.