X hits on this document

41 views

0 shares

0 downloads

0 comments

1 / 11

2.4 Aromatic Dimethacrylates

Aromatic dimethacrylates, particularly 2,2-bis[4-(2-hydroxy-3-methacryloxyprop-1- oxy)phenyl]propane (BisGMA), have been used extensively in dentistry for photocurable fillings.202 BisGMA, shown below in Figure 2.15, can be formed by the reaction of bisphenol A with glycidyl methacrylate. In dentistry, large concentrations of fillers are mixed in with BisGMA to provide color, to control the exotherm, to allow for pre-cure molding (in the form of a paste), to provide post-cure strength, and to reduce post-cure shrinkage by reducing the coefficient of expansion (CTE). BisGMA is extremely viscous and difficult to work with due to intermolecular hydrogen bonding between the hydroxyl groups, and is usually diluted with triethylene glycol dimethacrylate.203

OH

  • O

    O

O

OH

  • O

    O

O

Figure 2.15 2,2-Bis[4-(2-hydroxy-3-methacryloxyprop-1-oxy)phenyl]propane (BisGMA)

McGrath, et al., produced an extensive class of novel aromatic dimethacrylates with no pendant hydroxyl groups, examples of which are shown in Figure 2.16. These novel dimethacrylates were less viscous, thus easier to work with. Additionally, they exhibited less post-cure shrinkage, which is an extremely desirable property for any polymerization. For both of these reasons, less filler was required in dental applications, and potentially, in bone cement applications. Many of these polymers produced from the

202 203

Schmitt, W.; Purrmann, R.; Jochum, P.; Zahler, W.D., (ESPE) US Patent, 1975, 3,923,740. Schmitt, W.; Purrmann, R.; Jochum, P.; Zahler, W.D., ibid.

48

Document info
Document views41
Page views41
Page last viewedMon Jan 23 00:48:27 UTC 2017
Pages11
Paragraphs185
Words1863

Comments