Comparative evaluation of four treatments for postorthodontic white spot lesions: a randomized controlled trial.

OBJECTIVES: To evaluate the treatment efficacy of fluoride toothpaste alone and those of adjunctive use of resin infiltration, sodium fluoride varnish, and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on white spot lesions (WSLs). MATERIALS AND METHODS: Seventy-nine patients (356 teeth) with WSLs after orthodontic treatment were randomly allocated into four groups. The WSLs of the participants received resin infiltration only at baseline, and the other groups received fluoride varnish, CPP-ACP mousse, and placebo treatment every 6 months, respectively. A toothpaste containing 1400 ppm fluoride and toothbrushes were distributed to all participants, and oral hygiene instructions were provided. Photos of the teeth with WSL were taken to compare the change between groups which was measured by ImageJ software. RESULTS: Twelve months later, different degrees of reduction in the area of WSLs were observed in all groups. The percentage of lesion area reduction in WSLs in the resin infiltration group was 46.6%, which was significantly higher than that in fluoride varnish group (26.6%), CPP-ACP group (28.6%), and control group (29.8%), and the differences were statistically significant (p < 0.001). CONCLUSIONS: This study shows that after 1-year follow-up, the use of fluoride toothpaste, with or without the use of fluoride varnish or CPP-ACP, can reduce the area of WSLs. While resin infiltration can immediately improve dental aesthetics and continuously improved in 12 months, resin infiltration group showed much better results than other groups. TRIAL REGISTRATION: Clinical Trials Registration Number: ChiCTR2000032516. CLINICAL SIGNIFICANCE: The use of fluoride toothpaste, with or without adjunctive use of fluoride varnish and CPP-ACP, can reduce the area of WSLs, while resin infiltration treatment has additional effect and can immediately improve dental aesthetics.

Mosaic Evolution of Beta-Barrel-Porin-Encoding Genes in Escherichia coli.

Bacterial porin-encoding genes are often found under positive selection. Local recombination has also been identified in a few of them to facilitate bacterial rapid adaptation, although it remains unknown whether it is a common evolutionary mechanism for the porins or outer membrane proteins in Gram-negative bacteria. In this study, we investigated the beta-barrel (ß-barrel) porin-encoding genes in Escherichia coli that were reported under positive Darwinian selection. Besides fhuA that was found with ingenic local recombination previously, we identified four other genes, i.e., lamB, ompA, ompC, and ompF, all showing the similar mosaic evolution patterns. Comparative analysis of the protein sequences disclosed a list of highly variable regions in each family, which are mostly located in the convex of extracellular loops and coinciding with the binding sites of bacteriophages. For each of the porin families, mosaic recombination leads to unique combinations of the variable regions with different sequence patterns, generating diverse protein groups. Structural modeling indicated a conserved global topology among the different porins, with the extracellular surface varying a lot due to individual or combinatorial variable regions. The conservation of global tertiary structure would ensure the channel activity, while the wide diversity of variable regions may represent selection to avoid the invasion of phages, antibiotics or immune surveillance factors. Our study identified multiple bacterial porin genes with mosaic evolution. We hypothesize that this could be generalized strategy for outer membrane proteins to both maintain normal life processes and evade the attack of unfavored factors rapidly. IMPORTANCE Microevolution studies can disclose more elaborate evolutionary mechanisms of genes, appearing especially important for genes with multifaceted function such as those encoding outer membrane proteins. However, in most cases, the gene is considered as a whole unit, and the evolutionary patterns are disclosed. Here, we report that multiple bacterial porin proteins follow mosaic evolution, with local ingenic recombination combined with spontaneous mutations based on positive Darwinian selection, and conservation for most structural regions. This could represent a common mechanism for bacterial outer membrane proteins. The variable regions within each porin family showed large coincidence with the binding sites of bacteriophages, antibiotics, and immune factors and therefore would represent effective targets for the development of new antibacterial agents or vaccines.

[Relationship of concentration of lactoferrin and lysozyme in saliva and dental caries in primary dentition].

OBJECTIVE: To explore the relationship between the concentrations of lactoferrin and lysozyme in saliva and dental caries in primary dentition among Chinese children. METHODS: Forty children with high dmft score (dmft > or = 5) and 40 caries-free children (dmft = 0) were sampled and assigned into two groups. Total salivary proteins was measured by means of bicinchoninic acid. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was performed to analyze the images of target straps. Lactoferrin and lysozyme were detected using Western blotting method. RESULTS: The total salivary protein in high dmft group [(852.02 +/- 206.14) mg/L] was lower than that of caries-free group [(1032.44 +/- 221.99) mg/L, P < 0.001]. The ratio of 77,000 protein in high dmft group [(12.50 +/- 7.73) IA/microg] was significantly higher than that of the caries-free children [(8.71 +/- 4.28) IA/microg, P = 0.009], while there was no significant difference for 14,500 protein between them (P = 0.137). The ratio of lactoferrin was higher in high dmft group [(229.04 +/- 197.14) IA/microg] than that in caries-free children [(144.07 +/- 99.91) IA/microg, P = 0.018], while no significant difference for lysozyme between the two groups (P = 0.091). CONCLUSIONS: Saliva protein is closely related to caries in primary dentition. Lactoferrin may be one of the important components.