Translucency of Resin Modified Glass Ionomer Restoratives

Objectives: � This in vitro study evaluated the translucency of resin modified glass ionomer cements (RMGIs) compared to leading composites over time.

 

Methods: �

Materials tested were Riva LC A2 (1, SDI), Fuji II LC A2 (2, GC America), Riva LC HV A2 (3, SDI), Photac-Fil Quick Aplicap A2 (4, 3M ESPE), Ketac� Nano A2 (5, 3M ESPE), and Filtek Supreme Ultra composite shades A2B, A2E, WE �(6, 7, 8, 3M ESPE).��������������

 

Triplicate disks (n=24) were fabricated from each product by dispensing material into a 16mm diameter stainless steel mold, which was covered and compressed with a mylar strip and glass slide on both sides. The molds were light cured for 1min on each side (SDI Radii Plus), and the thickness of the disks were measured (1.00�0.05mm).� The disks were stored at 37�C in de-ionized water prior to measurement of their opacity.� Opacity was measured using the contrast ratio (CR) method with an XRite spectrometer in an integrating sphere geometry.� The CR was obtained by comparing the sample against a black glass background and white tile.� Water was placed between the disk and substrate to obtain good optical contact.� Measurements were made one hour after preparation, followed by 3 and 10 days.

 

Results:

The opacities were analyzed using ANOVA and Multiple Range Test (LSD, 95% confidence level, p-value < 0.05).

Table 1: Opacity (CR � SD)
Group	1	2	3	4	5	6	7	8
1 hour	36.76 � 1.91	47.81 � 0.26	45.63 � 1.71	50.36 � 0.74	47.39 � 1.29	40.64 � 1.88	33.11 � 1.18	29.19 � 0.48
3 days	31.96 � 0.65	42.91 � 1.56	38.35 � 2.10	39.83 � 1.68	56.14 � 2.55	40.58 � 1.60	33.44 � 0.67	28.38 � 0.68
10 days	29.65 � 0.80	42.74 � 3.00	34.99 � 1.22	33.54 � 2.20	54.06 � 3.42	39.70 � 1.32	31.92 � 0.21	28.31 � 0.79

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Conclusions: � �Group 1 is the most translucent of the RMGIs tested.�� Three days after cure, the opacity of group 1 is similar to group 7 composite.� All the RMGIs except group 5 reduce opacity slightly during the first few days after cure.� If the RMGIs are used to replace enamel, the reduction in opacity will make the underlying tooth structure slightly more visible.����