Effects of whitening dentifrice on yttria-stabilized tetragonal zirconia polycrystal surfaces after simulating brushing

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• 作者：L&iacute ; gia Antunes Pereira Pinelli ; DDSc ; PhD^a ; ^{laizamgfais@foar.unesp.br} ; Amanda Caroline Gimenes Olbera^b ; Lucas Miguel Candido^c ; Larissa Natiele Miotto^d ; Selma Gutierrez Antonio ; DDSc ; PhD^e ; Laiza Maria Grassi Fais ; DDSc ; PhD^f
• 刊名：The Journal of Prosthetic Dentistry
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：117
• 期：1
• 页码：158-163
• 全文大小：1717 K
• 卷排序：117

文摘

The changes that occur after brushing yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) are unknown. These changes may favor the retention of microorganisms and chemisorption of water, impairing its longevity.ObjectiveThe purpose of this in vitro study was to evaluate the effects of a whitening dentifrice on Y-TZP surfaces after simulating 10 years of brushing.Material and methodsSeventy-two bar-shaped specimens (20×4×1.2 mm) were divided into 4 groups: storage in distilled water (SW, control), brushing with distilled water (BW), brushing with dentifrice (BD), and brushing with whitening dentifrice (BWD). Brushing was conducted using a linear brushing machine (878 400 cycles, 0.98 N, soft toothbrush). The mean roughness (Ra) was analyzed with a profilometer and the superficial topography with scanning electron microscopy (SEM) at baseline and after treatment. Crystalline phases were characterized using x-ray diffraction. Baseline and posttreatment Ra were analyzed using the 1-way ANOVA and Tukey HSD multiple comparison test; the paired t test was used for intragroup comparison (all α=.05).ResultsThe Ra (μm) means (before/after treatment) were SW 0.28/0.28; BW 0.32/0.31; BD 0.28/0.36; BWD 0.30/0.20. No statistically significant difference was found for Ra at baseline (P=.108) than for posttreatment results (P<.001); the BD group had higher Ra values when compared with baseline (P=.019); the BWD group had the lowest values (P<.001). The BD surfaces showed pronounced scratches and detachment of the surface, while BWD showed smoother surfaces; similar crystallographic results among groups were observed.ConclusionsBrushing Y-TZP with conventional dentifrice increased roughness, while brushing with whitening dentifrice reduced roughness. Neither dentifrice changed the crystallographic phases after brushing.