Decreasing polymethyl methacrylate bone cement concentration extends working and setting times in vitro

Area of Science:

• Biomaterials science
• Veterinary surgery
• Polymer chemistry

Background:

• Polymethyl methacrylate (PMMA) bone cement is used in various medical applications.
• Vocal fold augmentation in horses presents unique challenges requiring specialized biomaterials.
• Understanding the physical properties of diluted PMMA is crucial for its safe and effective application.

Purpose of the Study:

• To evaluate the setting and temperature characteristics of diluted PMMA bone cement.
• To determine the suitability of PMMA for in vitro vocal fold augmentation in horses.
• To establish optimal concentrations for desired working and setting times.

Main Methods:

• Four dilutions of PMMA bone cement were prepared with varying volumes of PMMA powder (15-30 mL) in 10 mL solvent.
• Setting time (tset), peak temperature (Tmax), and time to peak temperature (tmax) were measured using a data logger.
• Injectability and working time (twork) were assessed using an 18-gauge spinal needle and syringe.

Main Results:

• Peak temperatures ranged from 56°C to 101°C, increasing with PMMA concentration.
• Setting times, working times, and times to peak temperature decreased as PMMA concentration increased.
• No significant difference in peak temperature was found between the two highest concentrations (25 and 30 mL PMMAp).

Conclusions:

• Lower concentrations of PMMA bone cement provide longer working and setting times.
• Peak temperatures of diluted PMMA are concentration-dependent, with diminishing differences at higher concentrations.
• Further in vivo studies are needed to confirm the utility of diluted PMMA for equine vocal fold augmentation.