Influence of calcium lactate and sodium fluoride solution mouthwashes on enamel microhardness and dentin permeability during in-office bleaching

Objective: This study evaluated the influence of calcium lactate and sodium fluoride mouthwashes on enamelmicrohardness dentin permeability during in-office bleaching. Material Methods: For microhardnessevaluation, enamel blocks were randomly submitted to different treatments associated with bleachingagent using 40% hydrogen peroxide (Opalescence Boost PF 40%/ Ultradent; 3 sessions x 40-minute each)(n = 10): 1) Control: application bleaching agent; 2) Calcium lactate: 1-minute immersion before bleachingtreatment; 3) Sodium fluoride: for 1 minute treatment; 4) +sodium in solution, followed by sodiumfluoride treatment. Dentin discs received same treatment protocols (n 10) evaluatepermeability. Knoop microhardness assessments performed twice (at baseline and48 hours after end treatment). Results: The generalized linear model considering design ofrepeated measures over time showed that there was no significant difference between (p 0.9577)and 0.3267) regarding microhardness. Kruskal Wallis Dunn tests showedthat provided higher than othergroups 0.0009). Conclusion: use solution association within-office did not tooth enamel, although lactatemay increase permeability.KEYWORDSTooth bleaching; Dentin; fluoride; lactate; Hardness tests.