In vitro dietary stain build-up on smooth and roughened teeth

Objective: The aim of the present in vitro study was to investigate whether differences in enamel surface roughness impact the acquisition of dietary stain.

Methods: A previously presented stain prevention/removal model (Gordon, 2006, PEF/IADR, abstract 0092) was employed in the present study with minor modifications. Mounted bovine teeth (n=28) were abraded using abrasive discs (320grit SiC) to obtain a sufficiently large and flat surface area. Fourteen teeth were further polished (4000grit SiC) to obtain a smooth, mirrorlike enamel surface. Roughness of these samples was measured by non-contact profilometry using the Proscan 2000 (Scantron). The teeth were then subject to a series of dietary staining cycles consisting of alternating treatments with artificial saliva, chlorhexidine (Corsodyl) and tea with brushing after 8 and 16 cycles. The colour of the teeth (L*,a*,b*) was measured using a Hunter LabScan XE spectrophotometer at various times throughout the experiment. A one-way ANOVA at the 95% confidence level was employed (L* data). A multiple range test (Fisher's least significant difference procedure) at a 95% confidence level was performed to identify statistically homogeneous groups.

Results: Roughnesses (Ra) in µm of the samples were (SD): roughened – 0.330 (0.091); smooth – 0.093 (0.012).

	Mean change in L* (SD)
	Number of stain cycles
	4	8 (pre-brushing)	8 (post-brushing)	12	16 (pre-brushing)	16 (post-brushing)
Roughened teeth	-5.78 (1.13)	-10.40 (1.49)	-6.76 (1.37)	-10.88 (1.53)	-16.63 (1.87)	-7.63 (1.98)
Smooth teeth	-3.89 (1.08)	-7.81 (1.58)	-4.95 (1.32)	-9.54 (1.69)	-14.90 (1.68)	-5.81 (1.70)

There was a statistically significantly difference in stain accumulation measured by changes in L* between roughened and smooth teeth at all time points measured (p<0.05), with roughened teeth being more prone to dietary stain build-up than smooth ones.

Conclusion: Under the conditions of the study, smooth teeth acquire less stain than roughened teeth.