Changes in the properties of bulk-fill resins under conditions of gastroesophageal reflux and bulimia

Aim

Evaluate the roughness, microhardness and color change of different Bulk Fill resins when submitted to the condition of gastroesophageal reflux and bulimia.

Methods

60 specimens (n = 10) of Bulk-Fill composite resins were made: M₁ – Filtek™; M₂ – Tetric N-Ceram and M₃ – OPUS, through a matrix 2x6 mm and light cured by the VALO light source. After polishing, initial analyzes (48 hours - T₀) of surface roughness (Ra), microhardness (VHN) and color change (ΔE) were performed. To simulate the oral condition of severe gastroesophageal reflux and bulimia, the specimens were immersed in hydrochloric acid (S₁) (pH 1.7) 4 minutes a day, for 7 days. Control group specimens were immersed in artificial saliva (S₂). Subsequently to immersions, mechanical brushing was performed for 3 minutes, three times a day, simulating 7 days of brushing. And again, the analyzes of Ra, VHN and ΔE were performed (7 days - T₁). Thus, hydrochloric acid immersion, mechanical brushing and Ra analysis were repeated at 14 days (T₂) and 21 days (T₃); and T₂, T₃ and T₄ (3 years) for VHN and ΔE.

Results

After Shapiro-Wilk statistical test, ANOVA and Tukey test with Bonferroni adjustment (p>0.05), M₃ showed the lowest Ra at all times compared to the other resins, while the highest Ra was at T₀. M₁ and T₁ showed higher VHN. And M₂ and T₄ showed higher ΔE.

Conclusion

Bulk Fill resins can be indicated for patients with Gastroesophageal Reflux and Bulimia, nonetheless, Tetric N-Ceram resin showed the worst results.

Composite resins; Color; Hardness; Hydrochloric acid