Novel Composite Containing PLGA for Provisional Restoration

Objective: To examine the effect of biodegradable PLGA on the physical properties of a PEGDA composite in an attempt to design resin-based cement for use in provisional restorations.

Methods: Poly(glycolide-co-lactide) ((PLGA), Resomer^¢ç 502H) was mixed with PEGDA and Bis-GMA. The resin was subsequently mixed with 50% mass fraction glass fillers containing an initiator system (CQ and EDMAB), which covers base part. For a dual-cured composite, the catalyst part contains peroxide, PEGDA and inorganic fillers. Specimens were made and tested for the degree of conversion (DC), flexural strength, compressive strength, and degradation. ANOVA was done, followed by the Tukey post-hoc at a=0.05 to determine statistically significant difference.

Results: The behavior of physical properties of dual-cured PEGDA-based system in the initial and 4 weeks except for DC is shown below.

	Initial PLGA %(w/w)	DC(%) in 40sec & 5min	Flexural strength (MPa) (n=5)	Flexural modulus (GPa) (n=5)	Compressive strength (MPa) (n=5)	Wt. loss in PBS (%) (n=3)
A	0	63.5	11.222(2.043)	0.615(0.041)	100.5(12.5)	100
		87.8	11.775(3.726)	0.684(0.119)a	123.3(22.8)c,d	99.4(4.3)
B	10	67.9	7.967(3.297)	0.528(0.052)a,b	72.2(13.6)c	100
		85.3	8.766(0.615)	0.708(0.050) b	81.6(11.4)d	90.7(1.3)

The resin-based composites initiated by visible light (500MW/cm² for 40sec) under ambient conditions exhibited further increase in DC due to the post-polymerization by peroxide co-initiator. The presence of PLGA did not interrupt polymerization process. The mechanical properties from the experimental system with PLGA were comparable or slightly lower compared to control group. This is probably related to the microstructures of the composite, which are governed by morphological changes in PLGA. The wt. loss studies clearly demonstrated the degradation of PLGA while maintaining the mechanical properties.

Conclusion: These results indicated that resin-based composite containing biodegradable PLGA showed comparable properties and can be applicable to develop for temporary cementation of permanent restorations.