ABSTRACT
Although several studies have demonstrated the efficacy of AmF/NaF/SnCl2 solution in inhibiting dental erosion progression, measures for further improvement in its effectiveness are paramount. Thus, this in situ study evaluated whether the protective effect promoted by the AmF/NaF/SnCl2 solution would be enhanced by increasing its frequency of use. The study was conducted with 12 volunteers, a 4-phase (5 days each) randomized, crossover model. Extraoral erosive challenges (0.5% citric acid, pH 2.6, 6 × 2 min/day) and rinsing protocol (1 or 2 × 2 min/day) were performed. Before the in situ phase, human enamel samples were subjected to an in vitro surface softening (1% citric acid, pH 4.0, for 3 min). Four treatment protocols were tested using samples in replicas (n = 12): group G1 - deionized water (negative control); G2 - NaF solution (positive control, 500 ppm F-, pH 4.5); G3 - AmF/NaF/SnCl2 solution (500 ppm F-, 800 ppm Sn2+, pH 4.5) once a day; G4 - AmF/NaF/SnCl2 solution twice a day. Tissue loss and morphological changes were determined by optical profilometry (n = 12) and scanning electron microscopy (n = 3) analysis, respectively. Data were statistically analyzed by ANOVA with subsequent pairwise comparison of treatments. Tissue loss means (±SD in µm) for each treatment protocol and statistical differences were found as follows: G1 4.55 ± 2.75, G2 4.59 ± 2.13, G3 2.64 ± 1.55, and G4 1.34 ± 1.16. Although there was no difference between the 2 AmF/NaF/SnCl2 solution application regimens (once or twice a day), application of the product twice a day was the only treatment that was able to control erosion progression, differing from the control groups.
Subject(s)
Fluorides, Topical/administration & dosage , Mouthwashes/administration & dosage , Sodium Fluoride/administration & dosage , Tin Compounds/administration & dosage , Tooth Erosion/prevention & control , Adult , Cross-Over Studies , Disease Progression , Double-Blind Method , Humans , Prospective StudiesABSTRACT
Chromosome number, pairing relationship and meiotic behavior were evaluated in 24 Brazilian accessions of different Paspalum species as an initial screening to determine which of them might be useful in an interspecific hybridization program. The analysis showed that six were diploids, 16 tetraploids and two hexaploids. The pairing relationship was typical for the ploidy level and agreed with reported data. However, the meiotic behavior after diakinesis was much more abnormal than expected considering the pairing relationship. There was a high frequency of abnormal tetrads in the majority of accessions.
