Objective: To evaluate the in vitro effect of an electric or manual
toothbrush when used with or without a dentifrice on the abrasion of a
resin-modified glass ionomer (RMGI) restorative material.
Methods: A
stainless-steel mold (22mm x 12mm x 2mm) was used to create 32 resin-modified
glass-ionomer specimens (Fuji II LC, GC America) cured in 1-mm increments using
a halogen curing light (Optilux 501, SDS/Kerr) and stored for one week in
distilled water. All specimens were polished with Sof-Lex Discs (3M/ESPE). The
average of three surface roughness and vertical depth measurements per specimen
were determined at baseline using a surface profilometer (Perthometer S2,
Mahr). Eight specimens in each of 4 groups (n=8) were subjected to electric
(Oral-B 3D #8850 DLX, Oral-B) or manual (Tess) toothbrushing in a slurry with
or without a dentifrice (Colgate Total, Colgate-Palmolive). Toothbrushes were
mounted on a toothbrushing machine (similar to Manly V-8 cross-brushing
machine). A 200-gm force was applied to the mounted specimens. Each specimen
was brushed for the equivalent of 3 years of brushing (electric: 2.6 hrs;
manual: 5.55 hrs) at 1.5 Hz. Mean surface roughness (Ra) and maximum wear were
determined as the difference between mean pre- and post-brushing values. Data
was analyzed with a 2-way ANOVA, (a=0.05).
Results: A significant
difference for depth was found based on type of brush (p=.049) or dentifrice
(p<.0001) without a significant interaction (p=.9). For Ra, a significant
difference was found based on type of brush (p<.0001) or dentifrice
(P<.0001), however, there was a significant interaction (p<.0001).
Unpaired t-tests were used to make comparisons within groups.
Conclusions: Overall, the use of the electric toothbrush or dentifrice
resulted in significantly greater loss of depth of the RMGI. The use of the
electric toothbrush with dentifrice caused a significant increase in surface
roughness of the RMGI.
| Mean Change in Depth or Surface
Roughness (st dev) in Microns |
|
Toothbrush Type |
No Dentifrice |
Dentifrice |
| Depth |
Manual |
0.41 (3.28) * |
12.20 (7.11) ^ |
|
Electric |
3.91 (3.76) * |
16.16 (5.44) ^ |
| Ra |
Manual |
0.03 (0.08) # |
0.52 (0.29) |
|
Electric |
0.06 (0.11) # |
1.55 (0.43) |
| Unpaired t-tests; groups with the
same symbol are not significantly different (p>0.05) |
