Method: The study was conducted in two crossover phases of 2 h with 10 volunteers (washout of 1 day). The groups under study were: Palatal- blocks were subjected to saliva remineralization by palatal removable appliances; Mandibular- blocks were subjected to saliva remineralization by mandibular removable appliances. Before the in situ phase bovine enamel blocks were subjected to short-term acidic exposure by immersion in citric acid 0.05 M (pH 2.5) for 15 s. Than the superficial microhardness test was performed (confirming surface softening without tissue loss) and enamel blocks were selected and randomly divided into 2 groups and 10 volunteers. In situ phase consisted of each removable intra-oral appliance use for 2 hours by the volunteers. Enamel remineralization was measured by superficial microhardness test (% superficial microhardness change). In addition the volunteers answered a questioner in order to evaluate the acceptance of appliances use. The data were tested using Paired t-test (p<0.05).
Result: The mandibular removable intra-oral appliance promoted similar remineralization by saliva when compared to the palatal one (p>0.05). In general the palatal appliances resulted in best acceptance by the volunteers (comfort, speech: palatal 80% and mandibular 20% acceptance; swallowing: palatal 80% and mandibular 80%; close mouth movement: palatal 100% acceptance and mandibular 100% rejection).
Conclusion: The results of the present study shows that mandibular and palatal removable intra-oral appliances promoted similar enamel remineralization when used for 2 hours, however the palatal appliance was more comfortable.