This study evaluated the effect of an experimental paste containing hydroxyapatite in nanoparticles (nano-HA)/fluoride on dental de-remineralisation in situ. Thirteen subjects took part in this crossover/randomised/double-blind study performed in 4 phases (14 days each). Four sound and 4 pre-demineralised specimens were worn intraorally at each phase corresponding to the following treatments: Nanop Plus (10% HA, 0.2% NaF, nano-HA/fluoride), MI Paste Plus (casein phosphopeptide-amorphous calcium phosphate, 0.2% NaF), F (0.2% NaF) and placebo. Two-hundred and forty enamel and 240 dentine specimens were selected by using surface microhardness; half of them were subjected to pre-demineralisation and the other half remained sound. Sound specimens were further exposed to severe cariogenic challenge (20% sucrose in biofilm) in situ, while pre-demineralised specimens were not. All specimens were exposed to fluoride dentifrice slurry 2 × 1 min/day. Thereafter, the treatments were done for 4 min. The de-remineralisation was quantified by transversal microradiography. The data were statistically analysed by repeated-measures ANOVA/Tukey's tests (p < 0.05). Generally, no huge differences were found among the treatments. However, Nanop Plus was the only treatment able to significantly reduce dentine demineralisation (ΔZ, integrated mineral loss) and to improve enamel remineralisation (ΔΔZ, integrated mineral uptake) compared to placebo. No treatments were able to reduce enamel demineralisation, while for dentine remineralisation all treatments were similarly effective in improving ΔΔZ compared to placebo. Nanop Plus seems to have a positive influence on dental de-remineralisation, which should be further confirmed.

Titanium tetrafluoride (TiF4) is known for interacting with enamel reducing demineralization. However, no information is available about its potential antimicrobial effect.ObjectivesThis study evaluated the antimicrobial and anti-caries potential of TiF4 varnish compared to NaF varnish, chlorhexidine gel (positive control), placebo varnish and untreated (negative controls) using a dental microcosm biofilm model.Material and MethodsA microcosm biofilm was produced on bovine enamel previously treated with the varnishes, using inoculum from human saliva mixed with McBain saliva, under 0.2% sucrose exposure, for 14 days. All experiments were performed in biological triplicate (n=4/group in each experiment). Factors evaluated were: bacterial viability (% dead and live bacteria); CFU counting (log10 CFU/mL); and enamel demineralization (transverse microradiography – TMR). Data were analysed using ANOVA/Tukey's test or Kruskal-Wallis/Dunn's test (p<0.05).ResultsOnly chlorhexidine significantly increased the number of dead bacteria (68.8±13.1% dead bacteria) compared to untreated control (48.9±16.1% dead bacteria). No treatment reduced the CFU counting (total microorganism and total streptococci) compared to the negative controls. Only TiF4 was able to reduce enamel demineralization (ΔZ 1110.7±803.2 vol% μm) compared to both negative controls (untreated: ΔZ 4455.3±1176.4 vol% μm).ConclusionsTiF4 varnish has no relevant antimicrobial effect. Nevertheless, TiF4 varnish was effective in reducing enamel demineralization under this model.

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SUMMARY This study aimed to evaluate the marginal and internal adaptation of partial coverage crowns (ceramic onlays) fabricated with Press, CEREC BlueCam, and CEREC OmniCam systems, using two preparation designs and evaluating the internal discrepancies at different locations. Two phantom maxillary premolars (master teeth) received different preparation designs, with (BX) and without (NB) a modified occlusal box with round internal angles. Sixty IPS e-max ceramic restorations were fabricated with three systems: Press (n=20), CEREC BlueCam (n=20), and CEREC OmniCam (n=20). Both marginal and internal discrepancy width were measured by using a stereomicroscope at ×25 magnification. The data were evaluated statistically using analysis of variance followed by Tukey's Honestly Significant Difference test (α=0.05). The ceramic restorations fabricated with the Press system presented significantly smaller marginal and internal disadaptations than the BlueCam and OmniCam CEREC systems (p&lt;0.0001). Regarding the preparation designs, preparation BX presented the smallest marginal discrepancies for all fabrication systems and larger internal discrepancies than for restorations fabricated with the Press system. The occlusal location presented a larger internal discrepancy compared with the axial locations. Although the three systems resulted in the fabrication of restorations within a clinically acceptable adaptation with marginal discrepancies below 100 μm, the Press system presented the smallest marginal and internal discrepancies. An improved marginal adaptation was observed in the preparation design with a modified occlusal box with rounded internal angles.