Phenylmethylsulfonyl fluoride (PMSF) is a protease inhibitor widely used in research, but fluoride is released during its action and this knowledge has been neglected in dental research. Aim to evaluate if fluoride released by salivary protease action on PMSF affects enamel remineralization and fluoride uptake. Methods Groups of 10 enamel slabs, with caries-like lesions and known surface hardness (SH), were subjected to one of the following treatment groups: Stimulated human saliva (SHS), negative control; SHS containing 1.0 μg F/mL (NaF), positive control; and SHS containing 10, 50 or 100 µM PMSF. The slabs were subjected to a pH-cycling regimen consisting of 22 h/day in each treatment solution and 2 h/day in a demineralizing solution. After 12 days, SH was again measured to calculate the percentage of surface hardness recovery (%SHR), followed by enamel fluoride uptake determination. The time-related fluoride release from 100.0 µM PMSF by SHS action was also determined. Data were analyzed by ANOVA followed by Newman-Keuls test. Results The release of fluoride from PMSF by SHS was rapid, reaching a maximum value after 10 min. Fluoride released from PMSF was more effective in enhancing %SHR and increasing fluoride uptake in enamel compared with SHS alone (p < 0.05); furthermore, it was equivalent to the positive control (p > 0.05). Conclusion In conclusion, fluoride released by saliva from PMSF is available to react with enamel and needs to be taken into account in research using this protease inhibitor.

O objetivo deste estudo foi criar um suco sintético (SJ) para ser usado como substituto do suco de laranja natural em estudos de erosão dental, verificando o seu potencial erosivo. O SJ foi formulado com base na composição química de sucos de laranja de diferentes locais. Quarenta espécimes de esmalte e 40 de dentina radicular foram aleatoriamente alocados em 4 grupos experimentais (n=10): SJ; 1% Citric acid (CA); Minute Maid Original® (MM) e Florida Natural Original® (FN). Os espécimes foram imersos nas suas respectivas soluções por 5 min, 6x/dia por 5 dias, em um modelo de ciclagem de erosão-remineralização. Os espécimes de esmalte foram analisados por microdureza de superfície Knoop e perfilometria ótica, enquanto que os espécimes de dentina foram analisados somente por perfilometria. Os resultados foram analisados estatisticamente com o teste de ANOVA, seguido pelo teste de Tukey, considerando um nível de significância de 5%. Para o esmalte, a perda superficial e as alterações de microdureza encontradas para os grupos MM e SJ foram similares (p>0,05) e significantemente menores (p<0,01) do que as encontradas para o grupo CA. Para dentina, CA promoveu significantemente (p<0,01) a maior perda de superfície quando comparada aos outros grupos. Não foram encontradas diferenças significantes (p>0,05) entre a perda de superfície de dentina dos grupos MM e SJ. Concluiu-se que CA foi a solução mais erosiva e SJ apresentou um potencial erosivo semelhante ao do suco de laranja natural MM.

The aim of this study was to create a synthetic juice (SJ) to be used as a surrogate for natural orange juices in erosion studies, verifying its erosive potential. The SJ was formulated based on the chemical composition of orange juices from different locations. Forty enamel and 40 root dentin specimens were randomly assigned into 4 experimental groups (n=10): SJ; 1% Citric Acid (CA); Minute Maid Original® (MM) and Florida Natural Original® (FN). The specimens were immersed in their respective solutions for 5 min, 6x/day for 5 days, in an erosion-remineralization cycling model. Enamel specimens were analyzed by surface Knoop microhardness and optical profilometry and dentin specimens only by optical profilometry. Outcomes were analyzed statistically by ANOVA followed by Tukey’s test considering a significance level of 5%. For enamel, the surface loss and microhardness changes found for MM and SJ groups were similar (p>0.05) and significantly lower (p<0.01) than those found in the CA group. For dentin, CA promoted significantly greater (p<0.01) surface loss compared with all the other groups. No significant difference (p>0.05) was observed in dentin surface loss between MM and SJ. In conclusion, CA was the most erosive solution, and SJ had a similar erosive potential to that of MM natural orange juice.