Objective:  The purpose of this study is to evaluate gloss, translucency and physical properties of a new experimental radiopaque nanocluster heat cure composite (EX).  Method: The gloss was obtained by toothbrush method (abst. #621, J. Dent. Res. V82, March 2003). Diametral strength and flexural strength were measured according to ISO 4049. Opacity was measured by spectrophotomer, X-Rite Inc. Model # SP64.  Kerr BelleGlass NG (BG) Enamel Light shade was used as the control. The results are summarized in the table.

Results:

	Gloss (1 hr) after Toothbrushing	Opacity (Contrast ratio)	Flexural strength (MPa)	Diametral  strength (MPa)
EX	60.8 (2.4 )a	67.4 (0.3 )a	155 (14.3)a	61.0 (3.5)a
BG	51.7 (3.2)b	48.0 (0.1)b	140 (13.0)a	65.7 (5.0)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 gloss measurement and translucency between BG and EX

Conclusions: The flexural and diametral tensile strength of the experimental nanocluster composite and BelleGlass NG are similar but the gloss and opacity are significantly different.