A new class of Fillers for Dental Composites

Objectives:

Development of new filler materials for light curing dental composites

Methods:

The formulations were prepared containing Bis-GMA (2,2-bis[4-(2-hydroxy-3-methylacryloxypropoxy)-phenyl]propane associated with TEGDMA (2-methyl-2-propenoic acid). The photoinitiatior system was composed of camphorquinone  and 2-(dimethylamino)ethyl methacrylate. Fillers were added up to the filling degree described.

The preparation of dental composites using Quarzwerke MICROSPAR® filler took place by mixing all parts by hand to a visible bubble free paste.

Results:

	flexual bond strength [MPa]	shear bond strength [MPa]	vickers hardness [HV 5-20]	Roughness4); Ra [µm]
reference 0.7 µm 1)	115,6	22,6	47,0	-
reference 1.0 µm 2)	145,0	31,3	54,4	-
MICROSPAR 1351-980 MST	144,0	19,7	48,5	0,05
MICROSPAR 1351-900 MST	212,0	29,7	53,9	0,05
MICROSPAR 1351-600 MST	205,0	28,2	51,3	0,05
MICROSPAR mixture3)	203,0	31,3	47,6	0,05
1)	GM 39923 UF 0.7; 6,0% Methacrylsilane
2)	GM 27884 UF 1.0; 4,6% Methacrylsilane
3)	Mixture MICROSPAR 1351-900 MST / MICROSPAR 1351-600 MST; 40 wt% / 60 wt%
4)	polishing methode
	1st step: roughening via hard metal grinder
	2nd step: CompoMaster Coarse (Shofu)
	3rd step: CompoMaster  (Shofu)
	4th step: DirectDia Paste; Super Snap Buff Disk  (Shofu)

Conclusions:

• Compared to the common dental fillers based on Sr-Glasses and Ba-Glasses respectively, MICROSPAR^® systems show in the mechanical data similar or better performance
• All MICROSPAR^® systems show very good cure depth
• The linear shrinkage values are between 1.4% and 1.7%
• High filling degrees are practicable
• Good processability at high filler levels is ensured
• Highly transparentàno influence to the color adjustment
• Excellent polishing behavior of resulting fillings