Physical Properties of Radiopaque Nanocluster Composites

Objective: The purpose of this study is to evaluate gloss and physical properties of a two new experimental radiopaque nanocluster light cure composite (EX1) and (EX2). The physical properties of (EX1) and (EX2) are compared with 3M ESPE Filtek Supreme (FS) Yellow Translucent shade. Kerr Herculite XRV enamel hybrid composite was used as control.

Method: The gloss was obtained by toothbrush method, (abst. #621, J. Dent. Res. V82, March 2003). Diametral strength, flexural strength and x-ray radiopacity were measured according to ISO 4049. Opacity was measured by spectrophotomer, X-Rite Inc. Model # SP64. The results are summarized in the table.

Results:**

Gloss (1 hr) after Toothbrushing

Opacity (Contrast ratio)

Radiopacity
(3 mm of Aluminum)

Flexural strength (MPa)

Diametral strength (MPa)

EX 1

73.7 (0.5)^b

60.8 (1.0)^b

230 %^a

84.4 (12.1)^c

35.8 (3.2)^c

EX 2

74.4 (1.6 )^b

79.5 (0.6)^a

200 %^b

118.9 (10.6)^b

35.1 (2.2)^c

FS

77.7 (1.1)^a

34.5 (0.6)^d

60 %^c

131.0 (13.0)^b

53.0 (7.0 )^b

XRV

19.0 (2.8)^c

57.4 (0.5)^c

230 %^a

158.0 (9.0)^a

71.0 (2.1)^a

** Mean with the same letter within the same column are not statistically different (P<0.05)

ANOVA analysis (p<0.05) indicates that there are significant differences in physical properties amongst the nanocluster composites.

Conclusions: The flexural strength, diametral tensile strength and gloss of the experimental nanocluster composites were significantly lower than Filtek Supreme. The opacity and x-ray radiopacity were significantly higher.