Proanthocyanidin associated to vitamin E or palm oil on initial enamel erosion: in situ and in vitro study

This in vitro study evaluated the effect of proanthocyanidin, palm oil, and vitamin E against initial erosion. Bovine enamel blocks (n = 140) were divided into 14 groups: C+_SnCl2/NaF/Am-F-containing solution (positive control); C-_deionized water (negative control); O_palm oil; P6.5_6.5% proanthocyanidin; P2_2% proanthocyanidin; E_Vitamin E (97.8% oily tocopherol acetate); OP6.5_palm oil + 6.5% proanthocyanidin; P6.5O_6.5% proanthocyanidin + palm oil; OP2_palm oil + 2% proanthocyanidin; P2O_2% proanthocyanidin + palm oil; EP6.5_Vitamin E + 6.5% proanthocyanidin; P6.5E_6.5% proanthocyanidin + Vitamin E; EP2_Vitamin E + 2% proanthocyanidin; P2E_2% proanthocyanidin + Vitamin E. The acquired enamel pellicle (AEP) was previously formed in situ for 30 min. The specimens were treated in vitro with the solutions (500 µL, 30s). Then, the blocks were maintained for an additional hour in oral cavity to develop the modified AEP. The blocks were immersed in 0.5% citric acid (pH 2.5) during 30s. The response variable was the percentage of surface hardness loss (%SHL). Data were analyzed by one-way ANOVA and Fisher's LSD test (p<0.05). P6.5E (12±7_%SHL) was the only group that promoted similar protection to C+ (11±8_%SHL). O (17±13_%SHL), P2 (20±10_%SHL), OP6.5 (19±12_%SHL), P2O (21±13_%SHL), P6.5E (12±7_%SHL), and P2E (19±9_%SHL) exhibited %SHL similar to both C+ and C- (25±10_%SHL) groups (p<0.05). P6.5 (23±11_%SHL), E (27±8_%SHL), P6.5O (24±13_%SHL), OP2 (27±12_%SHL), EP6.5 (24±11_%SHL), and EP2 (26±11_%SHL) were different to C+ and similar to C-. It was concluded that the combination of 6.5% proanthocyanidin and vitamin E (P6.5E) was the most effective strategy against enamel erosion, aligning closely with the positive control.