The performance of probiotic fermented sheep milk and ice cream sheep milk in inhibiting enamel mineral loss.

The study aimed to evaluate the effects of two different sheep milk-based food matrices - fermented sheep milk and ice cream - with added probiotic bacteria (Lactobacillus casei 431) on dental enamel subjected to an in vitro highly cariogenic challenge. Sixty enamel blocks were selected and randomly allocated into five treatment groups (n=12): conventional fermented sheep milk (CFSM), probiotic fermented sheep milk (PFSM), conventional sheep milk ice cream (CSMIC), probiotic sheep milk ice cream (PSMIC) and control using deionized water. The blocks were subjected to highly cariogenic pH cycling and the products were applied (5min), in a blinded way, once a day to simulate a daily use for 8 consecutive days. A microhardness test was performed before and after the treatment to estimate the percentage of microhardness surface loss (% SML). Scanning electronic microscopy (SEM) was performed to confirm the mineral loss. All groups had lost microhardness after the experiment. However, CFSM and PFSM exhibited the most positive findings when compared to the control in both ice creams. Scanning electron microscopy showed less mineral loss in CFSM and PFSM compared with CSMIC, PSMIC and control after the cariogenic challenge. Overall, fermented milk decreased mineral loss from enamel subjected to a highly cariogenic challenge, regardless of the presence of probiotics in their composition, which had a higher efficacy compared to ice cream.

Energy dispersive x-ray spectroscopy evaluation of demineralized human enamel after titanium tetrafluoride application.

OBJECTIVE: Evaluate the presence of a titanium dioxide layer after application of titanium tetrafluoride on human permanent tooth enamel. STUDY DESIGN: The sample consisted of unerupted third molars. After the removal of the roots, each tooth was mesiodistally divided into 2 fragments, one reserved for the experimental group and the other for the control group. Before the treatments the fragments were artificially demineralized. The experimental group (n=5) received an application of 4% titanium tetrafluoride, for one minute and the control group (n=5) did not receive any treatment. The samples were sputter-coated with a 20-30nm gold layer as the energy dispersive x-ray spectrometer analysis was carried out in a scanning electron microscope and the results were descriptively analyzed. RESULTS: The titanium dioxide layer was present on all experimental samples with a titanium peak varying between 6.82 and 26.37%. This layer was not found in the control group. Fluoride and calcium fluoride precipitates were present in the samples treated with titanium tetrafluoride. CONCLUSION: Titanium dioxide layer was formed after one titanium tetrafluoride application, but it was not uniform. Further studies should be carried out so that both the morphology and thickness of such layers can be better understood.

Er:YAG laser irradiation to control the progression of enamel erosion: an in situ study.

This in situ study evaluated the effect of Er:YAG laser irradiation in controlling the progression of enamel erosion-like lesions. Fifty-six enamel slabs (330 KHN ± 10 %) with one fourth of the surface covered with resin composite (control area) were submitted to initial erosion-like lesion formation with citric acid. The slabs were divided into two groups: irradiated with Er:YAG laser and non-irradiated. Fourteen volunteers used an intraoral palatal appliance containing two slabs, in two phases of 5 days each. During the intraoral phase, in a crossed-over design, half of the volunteers immersed the appliance in citric acid while the other half used deionized water, both for 5 min, three times per day. Enamel wear was determined by an optical 3D profilometer. ANOVA revealed that when deionized water was used as immersion solution during the intraoral phase, lower values of wear were showed when compared with the groups that were eroded with citric acid, whether irradiated or non-irradiated with Er:YAG laser. When erosion with citric acid was performed, Er:YAG laser was not able to reduce enamel wear. Small changes on enamel surface were observed when it was irradiated with Er:YAG laser. It may be concluded that Er:YAG laser irradiation did not reduce the progression of erosive lesions on enamel submitted to in situ erosion with citric acid.