Quantitative evaluation of abrasion thickness of eroded dentine by sonic toothbrush with or without toothpaste
kazkato@dpc.aichi-gakuin.ac.jp; School of Dentistry, Aichi-Gakuin University, Nagoya, Japan
This study was carried out to evaluate the eroded dentine-abrading action of a sonic toothbrush by measuring abrasion thickness using an Electron Probe Micro-Analyzer (EPMA). Polished dentine slabs each with an exposed window (4 mm2) made using nail-varnish were immersed into (A) grapefruit juice (pH3.3), (B) wine vinegar (pH2.7) or (C) 0.83M acetic acid for 60, 120 or 180 minutes, respectively. The slabs were fixed and the tips of the bristles were placed on the eroded window perpendicular to the window floor, applying a pressure of 1 g per mm2. The slabs were then brushed for 1 minute using a sonic toothbrush (480Hz) with either slurry containing non-fluoridated toothpaste and water in a ratio of 1:4 or water. The slabs were cleaned ultrasonically, dipped into acetone to remove the nail-vanish and air-dried. Subsequently they were sputter-coated with platinum to examine using secondary-electron imaging. Then they were embedded in methacrylate and cross-sectioned in the middle of the windows. Their surfaces were polished, coated with carbon and examined using back-scattered electron imaging (COMPO). The area of dentine wear within the window was measured in the COMPO image by image analyzing which calculated abrasion thickness. Analysis using ANOVA indicated that abrasion thicknesses were affected by acid solution and working time with a significant interaction between these factors. However, there was an insignificant affect by slurry. The depth of wear (µm, mean}SD) after 60, 120 and 180 minutes treatment were 21.1}5.1, 38.2}6.8 and 47.5}8.1 in group A, 43.8}10.7, 64.2}12.8 and 73.9}16.6 in group B, and 42.1}11.7, 60.0}12.7 and 93.9}21.0 in group C, respectively. The results suggested that the influence of toothpaste on eroded dentine wear was limited.
Supported by KAKENHI (C) No. 24593178, Japan.
3-Factor Crossed Mixed Model ANOVA
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Tests of Between-Subjects Effects |
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Dependent Variable: Depth of wear |
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Source |
Type III Sum of Squares |
df |
Mean Square |
F |
Sig. |
|
Corrected Model |
65232.061a |
17 |
3837.180 |
23.894 |
.000 |
|
Intercept |
389179.929 |
1 |
389179.929 |
2423.418 |
.000 |
|
acid solution |
24247.096 |
2 |
12123.548 |
75.493 |
.000 |
|
slurry |
300.863 |
1 |
300.863 |
1.873 |
.174 |
|
working time |
33831.920 |
2 |
16915.960 |
105.335 |
.000 |
|
acid solution * slurry |
18.645 |
2 |
9.322 |
.058 |
.944 |
|
acid solution * working time |
4029.977 |
4 |
1007.494 |
6.274 |
.000 |
|
slurry * working time |
417.015 |
2 |
208.507 |
1.298 |
.277 |
|
acid solution * slurry * working time |
782.392 |
4 |
195.598 |
1.218 |
.307 |
|
Error |
19752.734 |
123 |
160.591 |
|
|
|
Total |
472740.157 |
141 |
|
|
|
|
Corrected Total |
84984.795 |
140 |
|
|
|
