Trace amount of bisphenol-A (BPA) can potentially be found in dental products which utilize bisphenol-A glycidyl dimethacrylate (bis-GMA) or its derivative (such as ethoxylated bis-GMA). Development of alternative resin matrices has been challenging due to good performance of bis-GMA type systems. This study investigated key mechanical properties of recently developed novel experimental BPA-free composites.
Method:
Materials evaluated include: two DENTSPLY/Caulk experimental BPA-free composites (BFC-1 and BFC-2), commercially available BPA-free composite Venus Diamond™ (Heraeus Kulzer) and Kalore™ (GC). Specimens for flexural strength (25X2X2 mm, n=6) were prepared, light-cured, and tested according to ISO 4049. Specimens for compressive strength (4X6mm, n=6) and barcol hardness (30X1mm, n=3) were prepared, light-cured, and tested according to DENTSPLY/Caulk’s internal test methods. Specimens for flexural and compressive testing were stored in DI-water at 37°C for 24-hour before final testing on Instron 3366 at crosshead speed of 0.75 mm/min for flexural testing and 5.0 mm/min for compressive testing.
Result: Evaluation results are shown in the table:
BPA-Free Composite |
BFC-1 |
BFC-2 |
Venus Diamond |
Kalore |
Filler Loading (wt%) |
80.0 |
81.5 |
81.2 |
82.0 |
Flexural Strength (MPa) |
170 (4) |
157 (3) |
169 (15) |
112 (3) |
Flexural Modulus (MPa) |
12872 (345) |
13198 (379) |
12088 (475) |
6941 (115) |
Compressive Strength (MPa) |
314 (14) |
317 (4) |
406 (28) |
262 (15) |
Compressive Modulus (MPa) |
6365 (515) |
6227 (381) |
5973 (180) |
4973 (164) |
Barcol Hardness (Hard ) |
82 |
84 |
84 |
77 |
Conclusion: The newly developed experimental BPA-free composites exhibited overall similar mechanical properties as compared to Venus Diamond, whereas Kalore showed substantially lower mechanical properties.
Keywords: BPA, Composites, Dental materials and Polymers