Time-lasting Ceramics Stain and Glaze: A Toothbrush Simulation Study

Objectives: To evaluate and compare color stability and gloss retention of ceramic stain and glaze under simulated toothbrushing using dentifrices with different relative dentin abrasion (RDA).
Methods: Square-shaped specimens (10×10×1.2mm, n=12) were fabricated from: feldspathic porcelain (FP) (VITA VMK Master, VITA), lithium disilicate (LD) (IPS e.max CAD, Ivoclar Vivadent), 3Mol% yttria partially stabilized zirconia (3Y-PSZ, Katana HT, Noritake), and 5Mol% yttria partially stabilized zirconia (5Y-PSZ, Katana HTML, Noritake). Each group of ceramics were externally stained and glazed according to manufacturer’s instructions. Each group was mounted in the Toothbrush Simulator (ZM3.12, SD Mechatronik). A toothbrush (Soft-head, Oral-B) was then mounted and set to apply a 300g force to the specimen. Two different RDA toothpastes were used: Regular toothpaste – 72 RDA (R) (Colgate Total, Colgate) and Charcoal toothpaste – RDA not specified (C) (Crest 3D Whitening Therapy with Charcoal, Colgate) were used to make a slurry mixture containing distilled water and toothpaste (2:1 ratio). Toothbrush wear was done using a linear motion for the corresponding cycle intervals: 5k, 10k, 30k, and 50k toothbrushing cycles. Change in color (CIEΔE2000) and Gloss measurements were collected using a reflection spectrophotometer (Ci 7600, X-rite) at baseline, 5K, 10K, 30K, and 50K toothbrushing cycles. Repeated measures analysis of variance within specimen factors (ceramic type, toothpaste and cycles) was performed using proc mixed with SAS 9.4 with an unstructured variance covariance matrix assessed by AIC criteria.
Results: ΔE₀₀ was significantly different at 50K cycles and with polycrystalline ceramics (P<0.0001). C-toothpaste was significantly different in ΔE₀₀ compared to R-toothpaste (P>0.0001). Loss of gloss was observed at 5K regardless type of ceramic and toothpaste abrasivity (P>0.0001).
Conclusions: Glass-phase ceramics retain stain and glaze longer than polycrystalline ceramics. C-toothpaste affect color and gloss stability. Gloss maybe lost within the first 6 months in patients mouth.