Experimental toothpastes containing ß-TCP nanoparticles functionalized with fluoride and tin to prevent Erosive Tooth Wear.

OBJECTIVES: The present study aimed to synthesize toothpastes containing Beta- TriCalcium Phosphate (ß-TCP) nanoparticles, functionalized with fluoride and tin, and test their ability to reduce erosive tooth wear (ETW). METHODS: Toothpastes were synthesized with the following active ingredients: 1100 ppm of fluoride (as sodium fluoride, F-), 3500 ppm of tin (as stannous chloride, Sn2+), and 800 ppm of ß-TCP (Sizes a - 20 nm; and b - 100 nm). Enamel specimens were randomly assigned into the following groups (n = 10): 1. Commercial toothpaste; 2. Placebo; 3 F-; 4. F- + ß-TCPa; 5. F- + ß-TCPb; 6. F- + Sn2+; 7. F- + Sn2+ + ß-TCPa and 8. F- + Sn2+ + ß-TCPb. Specimens were subjected to erosion-abrasion cycling. Surface loss (in µm) was measured by optical profilometry. Toothpastes pH and available F- were also assessed. RESULTS: Brushing with placebo toothpaste resulted in higher surface loss than brushing with F- (p = 0.005) and F- + ß-TCPb (p = 0.007); however, there was no difference between F- and F- + ß-TCPb (p = 1.00). Commercial toothpaste showed no difference from Placebo (p = 0.279). The groups F-, F- + ß-TCPa, F- + ß-TCPb, F- + Sn2+, F- + Sn2+ + ß-TCPa and F- + Sn2+ + ß-TCPb were not different from the commercial toothpaste (p > 0.05). Overall, the addition of ß-TCP reduced the amount of available fluoride in the experimental toothpastes. The pH of toothpastes ranged from 4.97 to 6.49. CONCLUSIONS: Although toothpaste containing ß-TCP nanoparticles protected enamel against dental erosion-abrasion, this effect was not superior to the standard fluoride toothpaste (commercial). In addition, the functionalization of ß-TCP nanoparticles with fluoride and tin did not enhance their protective effect. CLINICAL SIGNIFICANCE: Although ß-TCP nanoparticles have some potential to control Erosive Tooth Wear, their incorporation into an experimental toothpaste appears to have a protective effect that is similar to a commercial fluoride toothpaste.

Effect of brushing simulation on the wear behavior of repaired CAD-CAM restorations.

OBJECTIVE: The aim of the present study was to evaluate the influence of multidirectional brushing on the surface roughness, morphology, and bonding interface of resin-repaired CAD-CAM ceramic and composite restorations. MATERIALS AND METHODS: Twelve (N = 12) blocks (4 mm × 4 mm × 2 mm for parallel axis; 5 mm × 4 mm × 2 mm for perpendicular axis) of lithium disilicate glass-ceramic (IPS e.max CAD, Ivoclar AG) and CAD-CAM resin composite (Tetric CAD, Ivoclar AG) were obtained and repaired with direct resin composite (Clearfil AP-X, Kuraray). An abrasive slurry was prepared and the brushing was performed according to each restorative material and axis of brushing (n = 6; perpendicular to repair interface and parallel to repair interface) during 3,650 cycles (240 strokes per minute) to simulate 3 years of brushing. The surface roughness (Ra) and the profile variation for each material (restoration and direct repair resin composite) were measured at the baseline condition and after brushing, and the mean roughness and presence of steps at the repair interface were evaluated through factorial analysis of Variance (ANOVA). Scanning Electron Microscopy (SEM) images were taken to evaluate the surface topography of the repaired materials after brushing. RESULTS: The mean roughness of the repaired CAD-CAM restorations was affected by the brushing (P < .05), mainly when evaluating the repair material and the interface (P < .05), while the restorative CAD-CAM materials presented more stable values. The profile evaluation showed higher steps at the interface when repairing lithium disilicate than for CAD-CAM resin composite. CONCLUSION: Repaired CAD-CAM restorations were susceptible to wear after brushing simulation. The surface roughness of the direct resin composite was the most affected leading to step development at the interface, particularly in the repaired lithium disilicate samples. Cinical maintenance recalls and polishing protocols must be considered to enhance the longevity of such restorations.

The ability of different formulations of artificial saliva to protect dentin from erosive wear / Ação protetora de diferentes formulações de saliva artificial no desgaste erosivo

Objective: Evaluate the protective effect of artificial saliva formulations associated or not with mucin on dentin. Materials and Methods: Bovine dentin specimens were randomly allocated to 10 groups (n = 20) according to the artificial saliva tested and the presence or absence of mucin: Amaechi et al. (1998); Klimek et al. (1982); Vieira et al. (2005) and Eisenburger et al. (2001) and deionized water (control). Samples were submitted to an erosive cycle consisting of two immersions of 120 min in the saliva, followed by 1 min in hydrochloric acid solution, and new storage in saliva for 120 min. Surface loss (µm) was measured before and after the cycle. Data were analyzed using 2-way ANOVA and Tukey's test (p < 0.05). Results: A significant difference was observed for the saliva formulation but not for the presence of mucin. The deionized water provided the highest surface loss and the Eisenburger's saliva formulation the lowest. The groups testing the Amaechi, Klimek, and Vieira saliva did not present significant differences. Conclusion: Eisenburger's saliva formulation provides a higher protective effect against dentin erosion. The presence of mucin did not increase the erosion-preventive effect of artificial saliva formulations. (AU)

Objetivo: Avaliar o efeito protetor de formulações de saliva artificial associadas ou não à mucina sobre a dentina submetida a erosão. Material e Métodos: Espécimes de dentina bovina foram alocados em 10 grupos (n = 20) de acordo com a saliva testada e a presença ou ausência de mucina: . Amaechi et al. (1998); Klimek et al. (1982); Vieira e cols. (2005), Eisenburger et al (2001) e agua deionizada (controle). As amostras foram submetidas a um ciclo erosivo composto por duas imersões de 120 min na saliva, seguidas de 1 min em solução de ácido clorídrico e novo armazenamento na saliva por 120 min. A perda de superfície (µm) foi medida antes e depois do ciclo. Os dados foram analisados usando ANOVA 2 fatores e teste de Tukey (p <0,05). Resultados: Foi observada diferença significativa para a formulação de saliva, mas não para a presença de mucina. A água deionizada proporcionou a maior perda de superfície e a formulação de saliva de Eisenburger a menor. Os grupos que testaram a saliva Amaechi, Klimek e Vieira não apresentaram diferenças significativas entre si. Conclusão: A formulação de saliva de Eisenburger fornece o maior efeito protetor contra a erosão dentinária e a presença de mucina não aumentou o efeito preventivo de erosão de formulações de saliva artificial (AU).

Effect of sucralfate against hydrochloric acid-induced dental erosion.

OBJECTIVE: Devising effective measures for the prevention of hydrochloric acid (HCl)-induced erosion is of great significance. This is even more important in dentine, in which products have limited diffusion. Therefore, agents that can bind to proteins forming an acid-resistant gel-like coat, such as sucralfate, may stand out as a promising alternative. This study investigated the protective effect of sucralfate suspensions against HCl-induced dental erosion. MATERIALS AND METHODS: In the first experiment, hydroxyapatite (HAp) crystals were pre-treated with a commercial sucralfate suspension (CoSS, pH 5.9), a stannous-containing sodium fluoride solution (NaF/SnCl2 pH 4.5), two prepared sucralfate suspensions (PrSS, pH 5.9 and 4.5), or deionized water (DI, control). HAp dissolution was measured using a pH-stat system. In a subsequent experiment, embedded/polished enamel and root dentine slabs were allocated into five groups to be treated with one of the tested substances prior to and during erosion-remineralization cycles (HCl-2 min + artificial saliva 60 min, two times per day, 5 days). Surface loss was assessed profilometrically. Data were analyzed by ANOVA and Tukey's tests. RESULTS: HAp dissolution was as follows: NaF/SnCl2 < CoSS < PrSS/pH 4.5, while PrSS/pH 5.9 = DI and both did not differ from CoSS and PrSS/pH 4.5. In enamel, surface loss did not differ between CoSS and PrSS/pH 4.5, with both having lower surface loss than PrSS/pH 5.9 and DI and NaF/SnCl2 differing only from DI. In root dentine, surface loss was as follows: CoSS < PrSS/pH 5.9 < (NaF/SnCl2 = DI), while PrSS/pH 4.5 = CoSS = PrSS/pH 5.9. CONCLUSION: Sucralfate suspension provided anti-erosive protection to HCl-induced erosion. CLINICAL RELEVANCE: Sucralfate may protect teeth against erosion caused by gastric acid.