Mass and volume changes of novel chlorhexidine, polylysine, and composites based on calcium phosphate

OBJECTIVE: To determine how the mass and volume of experimental composites altered following immersion in distilled water (DW) and a simulated bodily fluid (SBF). METHODS: The factors researched comprised the use of either adhesive monomer (4-methacryloyloxyethyl trimellitate anhydrite) or Chlorhexidine level, Calcium Phosphates (CalP) level, Polylysine level, and Hydroxy Ethyl Methacrylate (2-HEM) level. Circle plates of 10 mm in diameter and 1 mm in thickness were created. Gravimetric measurements of the mass and volume changes in DW and SBF were made. RESULTS: The average mass increase was-2-5% and-1-4% in DW and SBF respectively. On adding CalP, the average increase was-6, 3.5, and 2% with 20, 10, and 0wt% of reactive CalP fillers. The mass change with high levels of Polylysine, and chlorhexidine (5 wt%) was on average-1% higherthan with low levels (0.5, and 0wt% respectively). Mass changes with the use of hydrophilic monomer 2-HEM were-0.5-1% greater than with the adhesive monomer. In comparison to SBF, 12% was the highest volume increase with 20 wt% CalP in DW. The ultimate volume changes for 10 wt% CalP in DW & SBF at 12 weeks was 7.5% and 5% respectively. Overall volume changes in DW and SBF with 0% by weight CalP were 4% and 2% respectively. CONCLUSION: Mass and volume changes was highest in DW as compared to SBF, while the composites showed the potential to release over period of time. This will make the composites ideal for filling the gaps created because of polymerization shrinkage.