The effect of immersion in beverages and dental bleaching agents on the surface roughness of resin composites

Introduction: Composite materials may be exposed to chemicals in food and beverages in the oral cavity, which can lead to changes in surface roughness. The aim of this in vitro study was to evaluate the surface roughness of two restorative materials after exposure to coffee and green tea followed by a dental bleaching procedure. Methods: For nanofilled composite and microhybrid composite, 15 samples each were fabricated. Five specimens from each composite were stored in instant coffee and green tea for 4 h a day. After 30 days of immersion, specimens received dental at-home bleaching, using 16% carbamide peroxide (CP), for 7 h a day. The control group was stored in deionized water for 30 days. Surface roughness was determined by profilometry 24 h after polymerization, after 30 days of immersion, and after bleaching. The data were analyzed using a t-test for paired samples and mixed analysis of variance, at a 0.05 significance level. Results: Neither beverages nor CP treatment significantly altered the surface roughness of the composites. There was no difference between the tested composite materials regarding roughness. Conclusion: Surface roughness of the microhybrid and nanohybrid composites was not modified by coffee, green tea, and subsequent whitening treatment

Stabilnost boje dentalnih kompozita nakon uranjanja u napitke i postupaka izbjeljivanja

Objectives: The study aimed to compare the color stability of two different light-cured composites after immersion in three liquids and the effectiveness of 16% carbamide peroxide (CP) in removing the discoloration. Material and methods: Color stability of a microhybrid (Z250, 3M ESPE) and nanocomposite (Z550, 3M ESPE) was evaluated after immersion in instant coffee, tea, Coca-Cola, and deionized water as a control group (n=5). Samples were kept in liquids for four hours daily at 37°C for 30 days. Furthermore, 16% CP was applied for the following 14 days, simulating night whitening. A digital spectrophotometer was used for color measurement based on the CIEL*a*b* color coordinates. The color changes (∆E) were measured at baseline, after immersion in the beverages, and also after the teeth whitening procedure. Mixed and factorial ANOVA followed by Bonferroni’s posthoc test were used for statistical evaluation (p≤0.05). Results: Tested resin composites showed a color change over the acceptability threshold (ΔE*> 3.48) after immersion in coffee and tea. Nanocomposite reported a significant increase in discoloration in coffee after 30 days (p 3,48) poslije uranjanja u kavu i čaj. Nanokompozit je znatno povećao promjenu boje u kavi poslije 30 dana (p < 0,05). Boja obaju materijala značajno se promijenila (p < 0,05) duž svih triju L*a*b* osi u kavi i čaju u tamniju, žutu i crvenu. Izbjeljivanje 16-postotnim CP-om bilo je učinkovito u uklanjanju vanjske diskoloracije u oba ispitivana kompozitna materijala. Zaključak: Kava i čaj prouzročili su klinički uočljive promjene boje u ispitanim dentalnim kompozitima s kumulativnim učincima. Izbjeljivanje je učinkovita metoda za uklanjanje diskoloracije s površine kompozitnih nadomjestaka