Influence of fluoride characteristics on tooth surface protection in an erosive condition: A multifaceted characterization approach.

OBJECTIVE: To evaluate the effect of fluoride consistency and composition to protect enamel and dentin against the dental erosion. MATERIALS AND METHODS: Bovine enamel and dentin specimens were treated with artificial saliva, neutral fluoride gel (NFG), acidulated phosphate fluoride gel (AFG), neutral fluoride foam (NFF), and acidulated phosphate fluoride foam. The samples were subjected to cycling. Micro energy-dispersive X-ray fluorescence spectrometry, surface roughness (Ra), contact angle (CA), and scanning electron microscopy (SEM) were performed. Composition, CA and Ra data were analyzed by ANOVA and multiple comparison test (p < 0.05). RESULTS: The dentin protected had a significantly higher mineral content than in the control. Eroded unprotected enamel had higher Ra values than normal surfaces. Fluoride treatments increased the Ra in dentin samples. AFG increased the CA in enamel. Fluoride foams increased CA in dentin with reduced mineral loss. SEM analysis found a deposited layer on enamel treated with AFG and remnants of deposits on dentin treated with NFG and NFF. CONCLUSION: Regardless of the form of application, fluoride provided protection against erosion, however with different levels. CLINICAL SIGNIFICANCE: Applying the adequate fluoride form is relevant since the formulations have different effects on both enamel and dentin.

Biomineralization induced by chitosan and collagen-based materials with fluoride for dentin coverage: Chemical and morphological analysis.

The prevention and treatment of erosive tooth wear are becoming increasingly important due to its increasing prevalence. The use of natural solutions to modify dental surfaces has become an area of research. Organic materials such as chitosan and hydrolyzed collagen may be a promising option to treat dentin. This in vitro study aimed to evaluate the influence of chitosan or hydrolyzed collagen, alone or combined with acidulated phosphate fluoride (APF) gel, on the composition and morphology of dentin after erosion. Bovine dentin samples were prepared (n = 84) and treated with artificial saliva (AS, negative control); APF gel (F, positive control); chitosan solution (Chi); hydrolyzed collagen solution (Col); fluoride/chitosan composition (F_Chi); and fluoride/hydrolyzed collagen composition (F_Col). Erosive cycles (six cycles of immersion in orange juice for 1 min, followed by immersion in AS for 1 hr) were performed. The materials were characterized by their morphology, composition, and particle size distribution. Micro-energy dispersive X-ray fluorescence spectroscopy and scanning electron were used to evaluate the dentin's inorganic chemical composition and morphology. The F_Col and F groups had a reduction in calcium loss by 17 and 26%, respectively (p < .001). Both of these groups still had a covering layer of agglomerates at the dentin surface after the erosive cycles. The fluoridated chitosan or collagen solutions improved the dentin resistance to erosion as a novel hybrid-fluoride-based material approach to provide surface protection from erosion.

A Brazilian multicenter pilot case series on the efficacy of photobiomodulation therapy for COVID-19-related taste dysfunction.

BACKGROUND AND AIM: Among the most common symptoms of COVID-19 is taste dysfunction, which has a ranging clinical presentation. As well as its pathophysiology remains to be unclear, there is not enough information about the efficacy and safety of the available treatments. This study aims to report a series of cases using PBMT for the management of COVID-19-related taste impairment. CASE SERIES: 8 female and 2 male patients sought medical help for taste impairment (either partially or completely) after COVID-19 infection. Photobiomodulation therapy (PBMT) on the tongue mucosa was then proposed but with 3 different protocols. Taste perception at baseline and before every laser session was evaluated using a visual analog scale. Irrespective of the PBMT protocol, taste recovery was noted in all cases but with varying degrees of improvement. CONCLUSION: given the high prevalence rates of taste dysfunction in COVID-19 patients and the lack of information about the available treatments, PBMT seems to be a promising therapeutic modality but not dependent on the total number of laser sessions and the interval between them. The choice of the most suitable laser protocol as well as the knowledge of the exact photonic mechanisms, however, need to be better studied.

Intranasal photobiomodulation therapy for COVID-19-related olfactory dysfunction: A Brazilian multicenter case series.

Olfactory dysfunction is commonly seen in COVID-19 patients; however, little is known about the pathophysiology and management. The present study aimed to report a series of cases in which three protocols of intranasal photobiomodulation therapy (PBMT) were used for COVID-19-related olfactory dysfunction. Irrespective of the PBMT protocol, olfaction recovery was noted in all cases but with varying degrees of improvement. Although intranasal PBMT seems to be a promising therapeutic modality, more research is needed to better define effectiveness.

Effects of violet radiation and nonthermal atmospheric plasma on the mineral contents of enamel during in-office dental bleaching.

AIM: This in vitro study assessed the effects of in-office bleaching with gels (35% hydrogen peroxide [HP] or 37% cabamide peroxide [CP]) and two activation sources (violet radiation [LED] or nonthermal atmospheric plasma [NTAP]) on the mineral content of bovine enamel. MATERIAL AND METHODS: Dental blocks (n = 90) were assessed for initial microhardness before random distribution into nine groups: LED, LED + HP, LED + CP, NTAP, NTAP + HP, NTAP + CP, HP, CP and control (without treatment). Specimens were subjected to bleaching (2 clinical sessions, 7 days apart) using LED [20x/session, 1-min/each, 30 s apart] or NTAP [1x/session, 10 min]. µRaman determined contents of phosphate (PO43) and carbonate (CO32). Micro-energy dispersive X-ray fluorescence (µEDXRF) and spectrophotometry of enamel microbiopsy evaluated the calcium to phosphorous ratios (Ca/P). Two-way ANOVA and Tukey tests analyzed µRAMAN and µEDXRF results. Spectrophotometry results were analyzed using Kruskal-Wallis and Dunn tests. Pearson correlation tested µEDXRF and spectrophotometry results (α = 5%). RESULTS: NTAP and NTAP + HP exhibited greater PO43- content than LED, LED + HP and control (p < 0.05). No statistical differences were detected between CO32- among groups. While µEDXRF evaluation demonstrated that NTAP and LED did not alter Ca/P ratio of enamel (p > 0.05), spectrophotometry showed that Ca/P reduced for LED + HP (p < 0.05). No correlation was found between µEDXRF and enamel microbiopsy spectrophotometry (p > 0.05). CONCLUSIONS: Activation sources did not adversely impact enamel's phosphate and carbonate concentrations after specimens' exposure to bleaching gels (either HP or CP). Visible light radiation emitted by a LED source was shown to adversely impact specimens' Ca/P ratios when treated with HP-containing bleaching gels.

Saliva Preparation Method Exploration for ATR-FTIR Spectroscopy: Towards Bio-fluid Based Disease Diagnosis.

Saliva has garnered a lot of interest as a non-invasive, easy to collect, and biochemical rich sample for attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) based disease diagnosis. Although a large number of studies have explored its potential, the preparation methods used differ greatly. For large scale clinical studies to aid translation into clinics, the collection/processing methodology needs to be standardized. Therefore, in this study, we explored different saliva collection (spitting, method A/cotton soaking, method B) and processing protocols (unprepared, TS; supernatant from the centrifugation, CS; and drying, C) to find which gives the best ATR-FTIR signals. Analysis showed highest proteins, carbohydrates, amino acids, and nucleic acid + proteins/lipids in BTS, BCS, ACS, and BC, respectively. Notably, only BC shows a 1377 cm-1 nucleic acid band that is also uniquely identified in multivariate analysis. We conclude that the collection-processing protocol should be based on a biochemical component that best gives a differential diagnosis.

Raman spectroscopy-multivariate analysis related to morphological surface features on nanomaterials applied for dentin coverage.

Raman spectroscopy and scanning electron microscopy (SEM) were used to investigate the effect of coating materials and acidulated phosphate fluoride gel (APF) treatment on dentin before and after erosion-abrasion cycles. A multi-walled carbon nanotube/graphene oxide hybrid carbon-based material (MWCNTO-GO), nanohydroxyapatite (nHAp), or a combined composite (nHAp/MWCNTO-GO) were used as a coating. Seventy root dentin fragments obtained from 40 bovine teeth were prepared and divided into groups (n = 10): negative control, artificial saliva - C, positive control - APF; nHAp; MWCNTO-GO; APF_nHAp; APF_MWCNTO-GO and APF_nHAp/MWCNTO-GO. All samples were subjected to cycles of demineralization (orange juice, pH ~3.7, room temperature, 1 min) followed by remineralization (saliva, 37 °C, 1 h). The remineralization procedures were followed by tooth brushing (150 strokes). The above cycle was repeated 3×/day for 5 days. The previous APF treatment of dentin allowed a better affinity of nHAp and MWCNTO-GO with the inorganic and organic portion of dentin, respectively. This interaction indicates the formation of a protective layer for the dentin surface and for the collagen giving possible protection against erosion. SEM micrographs illustrated the formation of a protective layer after application of the biomaterials and that it was partially or totally removed after the erosion and abrasion. Raman spectroscopy combined with multivariate analysis could distinguish samples with respect to treatment efficacy. The APF_nHAP/MWCNT-GO composite has shown to be a promising material since it has binding characteristics both to the inorganic and organic portion of the dentin and reduced solubility. Mineral-to-matrix ratio (MMR) parameter analysis confirmed the binding capability of MWCNTO-GO-based materials to dentin.

Chemical composition and roughness of enamel and composite after bleaching, acidic beverages and toothbrushing.

BACKGROUND: In this study was assessed the surface roughness and chemical composition of tooth enamel and composite resin after bleaching treatment, immersion in acidic beverages, and simulated toothbrushing. MATERIAL AND METHODS: One hundred and twenty dental blocks (10 x 10 x 3 mm) were randomly assigned (n = 10) according to surface treatment [none (N), bleaching (B), toothbrushing (T), and B+T] and storage medium [saliva (S), whiskey (W), and orange juice (O)]: experimental groups - N+S, N+W, N+O, B+S, B+W, B+O, S+T, W+T, O+T, B+S+T, B+W+T, and B+O+T. Two bleaching sessions were conducted using 38% hydrogen peroxide (3 applications). Surface roughness was measured using a roughness tester and composition was determined by micro energy-dispersive X-ray fluorescence spectrometry (µ-EDXRF) before and after treatments. Calcium/phosphorus (Ca/P) ratio in enamel and silica (Si) content in composite were evaluated. Data were statistically analyzed by ANOVA and Tukey's test (α = 0.05). RESULTS: Overall, increased values of surface roughness for enamel and composite were observed mainly after immersion in orange juice and bleaching/toothbrushing association. Moreover, this association and immersion in whiskey resulted in lower Ca/P ratio and after aging methods, bleached and bleached/toothbrushed groups showed decreased in Ca/P ratio compared to initial values. All groups showed Si content decrease at the end, except the group without surface treatment and immersed in saliva, and bleaching followed by immersion in orange juice and toothbrushing caused the highest Si reduction. CONCLUSIONS: Bleaching and toothbrushing combination strengthened the effects caused by acidic drinks on roughness and chemical composition of enamel and composite. Key words:Tooth bleaching, toothbrushing, physical properties, chemical properties.

Adverse effects of respiratory disease medicaments and tooth brushing on teeth: A scanning electron microscopy, X-ray fluorescence and infrared spectroscopy study.

The present study aims to evaluate the effect of brushing with fluoride dentifrice on teeth severely affected by erosion due to respiratory medicaments. Enamel (n = 50) and dentin (n = 50) bovine specimens were prepared and treated with artificial saliva (S-control), acebrofilin hydrochloride (AC), ambroxol hydrochloride (AM), bromhexine hydrochloride (BR), and salbutamol sulfate (SS) and subjected to cycles of demineralization (immersing in 3 mL, 1 min, three times a day at intervals of 1 hr, for 5 days) followed by remineralization (saliva, 37°C, 1 hr). Simulated brushing with fluoridated toothpaste was performed using 810 strokes in a reciprocal-action brushing simulator. Scanning electron microscopy, micro energy dispersive X-ray fluorescence (µ-EDXRF) spectroscopy and attenuated total reflection Fourier transform infrared (ATR FTIR) spectroscopy were then performed. µ-EDXRF images showed extensive erosion after treatment with all medicaments. SEM images showed enamel erosion in order SS > BR > AC = AM > S after brushing and fluoridation. FTIR results were in agreement. In case of dentin, µ-EDXRF measurements showed significant difference in mineral content (percent weight of calcium and phosphate) in SS + brushing + fluoridation treated enamel compared to control, while µ-EDXRF images showed erosive effects in the order SS > AM>BR > AC = S post brushing + fluoridation. SEM images showed erosion in the order SS > AM = BR > AC > S post brushing + fluoridation. Again, FTIR multivariate results were in agreement. Overall, our study shows that proper oral care is critical when taking certain medication. The study also demonstrates the possible use of FTIR for rapid clinical monitoring of tooth erosion in clinics.

Chemical and morphological evaluation of enamel and dentin near cavities restored with conventional and zirconia modified glass ionomer subjected to erosion-abrasion.

Microenergy dispersive X-ray fluorescence (µ-EDXRF) spectroscopy and scanning electron microscopy (SEM) were used to test the hypothesis that zirconia modified glass ionomer cement (GIC) could improve resistance to erosion-abrasion to a greater extent than conventional cement. Bovine enamel (n = 40) and dentin (n = 40) samples were prepared with cavities, filled with one of the two restorative materials (GIC: glass-ionomer cement or ZrGIC: zirconia-modified GIC). Furthermore, the samples were treated with abrasion-saliva (AS) or abrasion-erosion cycles (AE). Erosive cycles (immersion in orange juice, three times/day for a duration of 1 min over a 5 day period) and/or abrasive challenges (electric toothbrush, three times/day for a duration of 1 min over a 5 day period) were performed. Positive mineral variation (MV%) on the enamel after erosion-abrasion was observed for both materials (p < 0.05), whereas a negative MV% on the dentin was observed for both materials and treatments (p < 0.05). The SEM images showed clear enamel loss after erosion-abrasion treatment and material degradation was greater in GIC_AE compared to those of the other groups. Toothbrush abrasion showed a synergistic effect with erosion on substance loss of bovine enamel, dentin, GIC, and ZrGIC restorations. Zirconia addition to the GIC powder improved the resistance to abrasive-erosive processes. The ZrGIC materials may find application as a restorative material due to improved resistance as well as in temporary restorations and fissure sealants.

In vivo Raman spectroscopic characteristics of different sites of the oral mucosa in healthy volunteers.

OBJECTIVES: Investigate the biochemistry of in vivo healthy oral tissues through Raman spectroscopy. We aimed to characterize the biochemical features of healthy condition in oral subsites (buccal mucosa, lip, tongue, and gingiva) of healthy subjects. More specifically, we investigated Raman spectral characteristics and biochemical content of in vivo healthy tissues on Brazilian population. This characterization can be used to better define normal tissue and improve the detection of oral premalignant conditions in future studies. MATERIALS AND METHODS: For spectroscopic analysis a Raman spectrometer (Kaiser Optical Systems imaging spectrograph Holospec, f / 1.8i-NIR) coupled with a laser 785 nm, 60 mW was used. Raman measurements were obtained by means of an optical fiber (EMVision fiber optic probe) coupled between the laser and the spectrometer. Three spectra per site were acquired from the lip, buccal mucosa, tongue, and gingiva of ten healthy volunteers. This resulted in 30 spectra per oral sub-site and in total 120 spectra. RESULTS: We report detailed biochemical information on these subsites and their relative composition based on deconvolution studies of their spectra. Finally, we also report classification efficiency of 61, 83, 41, and 93% for buccal, gingiva, lip, and tongue respectively after applying multivariate statistical tools. CONCLUSIONS: We quantitated the contribution of various biochemicals in terms of percentage, and this will enable comparison not only across anatomical sites but also across studies. Raman spectroscopy can rapidly probe tissue biochemistry of healthy oral regions. Moreover, the study suggests the possibility of using Raman spectroscopy combined with signal processing and multivariate analysis methods to differentiate the oral sites in healthy conditions and compare with pathological conditions in future studies. CLINICAL RELEVANCE: The spectral characterization of the healthy condition of oral tissues by a noninvasive, label-free, and real-time analytical techniques is important to create a spectral reference for future diagnosis of pathological conditions.

Effect of radiotherapy on the chemical composition of root dentin.

BACKGROUND: The radiotherapy can directly affect the bond strength of the adhesive materials, interfering in the prognosis of restorative treatments, which may be caused by chemical changes in dentin structure. METHODS: Twenty inferior homologues premolars were distributed in 2 groups (in vitro study) (n = 10): nonirradiated and irradiated. The specimens were submitted to the analysis of phosphate (ν1 PO43- ;ν2 PO43- ;ν4 PO43- ), carbonate (ν3 CO32- ), amide I, CH2 , amide III, and amide I/III ratio by confocal Raman spectroscopy. Data were submitted to statistical analysis (T test, P < .05). RESULTS: In intracanal dentin, the irradiated group had lower ν4 PO43- values (1.23 ± 0.06) compared to nonirradiated group (1.40 ± 0.18) (P < .05), with no difference for ν1 PO43- and ν2 PO43 peaks (P > .05). The irradiated (1.56 ± 0.06) had lower carbonate, amide III (1.05 ± 0.19), and amide I/III ratio values (0.19 ± 0.06) compared to nonirradiated group (1.42 ± 0.10, 1.28 ± 0.24, and 0.31 ± 0.10, respectively) (P < .05). For medium dentin irradiated group (1.30 ± 0.12) had lower phosphate values compared to nonirradiated group (1.48 ± 0.22) (P < .05). In cementum, there was no statistical difference between the groups. CONCLUSION: The radiotherapy was able to cause changes in ν4 PO43- , carbonate, and amide III peaks of root dentin.

Physicochemical changes in enamel submitted to pH cycling and bleaching treatment.

OBJECTIVE: The purpose of this study was to assess the hardness, mineral content, surface roughness, and micromorphology of sound and slightly demineralized enamels, before and after bleaching procedure using 10% carbamide peroxide. METHODS: Sixty bovine dental blocks were randomly divided into the following two groups: 30 slabs were submitted to three cycles of pH and 30 slabs were noncycled. Hardness (n=10) was measured using the microhardness tester with Knoop indenter under a 50 g load for 5 seconds. The calcium/phosphate (Ca/P) ratio (n=10) was obtained using a micro-energy-dispersive X-ray fluorescence (µ-EDXRF) spectrometer. The measurement of roughness average (n=10) was performed using a surface roughness tester. Specimens were bleached 6 hours/day during 21 days, and then, physicochemical properties were re-evaluated. Two additional specimens were carried out to evaluate surface micromorphology using the scanning electron microscopy. Data were statistically analyzed by ANOVA and Tukey's test (α=0.05). RESULTS: Sound and slightly demineralized enamels showed no difference in Ca/P ratio after dental bleaching according to the µ-EDXRF analysis, but the Ca/P ratio decreased after bleaching for slightly demineralized enamel. Bleaching treatment decreased the hardness and increased the surface roughness, causing micromorphology alterations. CONCLUSION: Therefore, bleaching procedure promoted change in bovine enamel surface and increased the demineralization of slightly demineralized enamel but not affected the mineral content of sound enamel.

Surface characteristics of a modified acidulated phosphate fluoride gel with nano-hydroxyapatite coating applied on bovine enamel subjected to an erosive environment.

This study evaluated the antierosive effect applying a modified acidulated phosphate fluoride (APF) gel containing nano-hydroxyapatite (nHAp) on the enamel surface before erosion. After polishing, the exposed flat enamel surfaces (n = 7/group) from bovine incisors were treated with artificial saliva (S - negative control), orange juice (ERO), APF gel (positive control) and APF_nHAp gel. All samples were subjected to six cycles of demineralization (orange juice, pH ~ 3.5, 10 min) followed by remineralization (saliva, 37°C, 1 hr). The enamel surface morphology, topography, and inorganic composition were analyzed using scanning electron microscopy, roughness testing, and micro energy-dispersive X-ray fluorescence spectrometry, respectively. The mean (standard deviation) roughness values (Ra, µm) were S, 0.13 (0.05); ERO, 0.25 (0.07); APF, 0.22 (0.08); and APF_nHAp, 0.17 (0.04). Ra values were significantly higher after ERO (p < .01) and APF (p < .05) treatments than after S. The enamel surface morphology was altered by the treatments, except for the S specimens. The mineral content of the enamel showed a clear trend with Ca and P reduction in the order of APF < S < APF_nHAp < ERO and APF < S < ERO < APF_nHAp, respectively. We can conclude that APF gel increased mineral concentration on the enamel. Moreover, the APF_nHAp material modified the composition and morphology of the enamel surface.

Effects of experimental bleaching agents on the mineral content of sound and demineralized enamels.

OBJECTIVE: High concentrations of hydrogen peroxide can cause adverse effects on composition and structure of teeth. However, the addition of calcium and fluoride in bleaching agents may reduce enamel demineralization. To evaluate chemical changes of sound and demineralized enamels submitted to high concentrations of hydrogen peroxide containing fluoride (F) or calcium (Ca). MATERIAL AND METHODS: Enamel blocks of bovine incisors with standard dimensions were obtained and half of them were submitted to pH-cycling to promote initial enamel caries lesions. Sound and demineralized enamel samples were divided into (n=10): (C) Control (no whitening treatment); (HP) 35% hydrogen peroxide; and two experimental groups: (HPF) 35% HP+0.2% F and (HPC) 35% HP+0.2% Ca. Experimental groups were submitted to two in-office bleaching sessions and agents were applied 3 times for 15 min to each session. The control group was kept in remineralizing solution at 37°C during the bleaching treatment. The surface mineral content of sound and demineralized enamels was determined through Fourier Transform Raman spectroscopy (FT-Raman), Energy dispersive Micro X-ray fluorescence spectroscopy (µ-EDXRF); and the subsurface, through cross-sectional microhardness (CSMH). In addition, polarized light microscopy (PLM) images of enamel subsurface were observed. RESULTS: According to three-way (FT-Raman and µ-EDXRF analyses) or two-way analysis of variance (ANOVA) (CSMH) and Tukey test (α=5%), the calcium or fluoride added to high-concentrated bleaching agents increased phosphate and carbonate concentrations on sound and demineralized enamels (p<0.05). However, HPC and HPF were unable to completely reverse the subsurface mineral loss promoted by bleaching on sound and demineralized enamels. The calcium/ phosphate (Ca/P) ratio of sound enamel decreased after HP treatment (p<0.001). CONCLUSION: Even though experimental bleaching agents with Ca or F reduced mineral loss for both sound and demineralized enamel surfaces, these agents were unable to reverse the enamel subsurface demineralization.

Evaluation of bone repair after application of a norbixin membrane scaffold with and without laser photobiomodulation (λ 780 nm).

Biocompatible membranes are widely used in medicine to stimulate bone repair. Several studies have demonstrated that laser photobiomodulation (PBM) also stimulates osteoblast proliferation and osteogenesis at the fracture site, leading to a greater deposition of bone mass and accelerating the process of bone consolidation. This work assessed the therapeutic effect of 780-nm laser PBM and a polystyrene membrane coated with norbixin and collagen (PSNC) on bone healing in rats with calvarial bone defect. Histological staining, Raman spectroscopy, and scanning electron microscopy (SEM) were used to evaluate the bone repair process. Four experimental treatment groups were compared: C, control; M, membrane only; L, laser PBM only; and ML, membrane + laser PBM. A bone defect was created in the calvaria of each animal, with each group subdivided into two subgroups that underwent euthanasia after 15 and 30 days treatment. The L and ML groups were irradiated (λ = 780 nm, ED = 6 J/cm2, P = 60 mW, t = 4 s) postoperatively on alternate days until they were euthanized. The bone concentration of hydroxyapatite (CHA) showed a clear gradation with increasing phosphate area in the order B (normal cortical bone) > L > M > ML > C for both periods. The PSNC membrane was effective in reducing the inflammatory process and served as a scaffold for bone repair. The laser PBM also showed positive effects on the bone repair process with increased deposition and organization of the newly formed bone. However, laser PBM failed to improve the bioactive properties of the membrane scaffold.

Genetic diversity and population structure of Vriesea reitzii (Bromeliaceae), a species from the Southern Brazilian Highlands.

The Southern Brazilian Highlands are composed by a mosaic of Mixed Ombrophilous Forest (MOF) and grassland formations, an interesting landscape for the study of population structure. We analyzed the genetic diversity within and among populations of the MOF-endemic bromeliad Vriesea reitzii by genotyping seven nuclear microsatellite loci in 187 individuals from six populations. We characterized levels of genetic diversity and assessed the genetic structure among populations. Vriesea reitzii populations showed high levels of genetic variation (number of alleles 28 - 43, allelic richness 3.589 - 5.531) and moderate levels of genetic differentiation (FST = 0.123, RST = 0.096). The high levels of genetic diversity may be explained by species life-history traits, such as habit and mating system. The moderate structure may be a product of the combination of ancient and contemporary gene flow, resulting from the expansion of the forest in the Holocene, and/or due to facilitated dispersal mediated by the MOF's mosaic landscape. The genetic results indicated no imminent threat to this bromeliad. However, the species is highly associated with the MOF, putting landscape conservation at the center of conservation efforts for the species' maintenance.

FT-Raman spectroscopy, µ-EDXRF spectrometry, and microhardness analysis of the dentin of primary and permanent teeth.

The chemical compositions (organic and inorganic contents) and mechanical behaviors of the dentin of permanent and deciduous teeth were analyzed and compared using X-ray fluorescence spectrometry (µ-EDXRF) Fourier transform Raman spectroscopy (FT-Raman) and a microhardness test (HD). Healthy fresh human primary and permanent molars (n = 10) were selected, The buccal surfaces facing upwards were stabilized in an acrylic plate, flattened, polished, and submitted to the µ-EDXRF, FT-Raman, and HD analysis. The results of the analysis were subjected to ANOVAs and Mann-Whitney U/Student's t multiple comparisons tests. The data showed similar values for the dentin of the primary and permanent teeth in P content, organic content (amide I peak), inorganic content ( PO43- - 430 and 590), and microhardness, Nevertheless, Ca content and Ca/P weight ratio were higher, and the CO32- peak was lower in the dentin of the permanent teeth compared to primary teeth. It be concluded that despite permanent teeth showed more Ca element, both substrates showed similar behavior of chemical and physical properties.

ATR-FTIR spectroscopy and µ-EDXRF spectrometry monitoring of enamel erosion caused by medicaments used in the treatment of respiratory diseases.

Medicaments essential for alleviation of diseases may sometime adversely affect dental health by eroding the enamel, owing to their acidic nature. It is therefore highly desirable to be able to detect these effects quickly and reliably. In this study, we evaluated the erosive capacity of four most commonly prescribed respiratory disease syrup medicaments on enamel using micro-energy-dispersive X-ray fluorescence spectrometry (µ-EDXRF) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). Fifty-five enamel fragments obtained from 30 bovine teeth were treated with artificial saliva (S), acebrofilin hydrochloride (AC), ambroxol hydrochloride (AM), bromhexine hydrochloride (BR), and salbutamol sulfate (SS); by immersing in 3 mL of respective solutions for 1 min, three times a day at intervals of 1 hr, for 5 days. µ-EDXRF analysis of enamel surface did not reveal significant erosion caused by the medications. However, ATR-FTIR showed a detectable shift in the phosphate (PO4 ) antisymmetric stretching mode (ν3 ) at ∼985 cm-1 for AM, BR, and SS, indicating erosion. Multivariate statistical analysis showed that AC, AM, SS, and BR could be classified with 70%, 80%, 100%, and 100% efficiency from S (control), further highlighting the ability of ATR-FTIR to identify degree of erosion. This suggests ATR-FTIR may be used to rapidly and nondestructively investigate erosive effects of medicaments.

Genetic diversity and population structure of Vriesea reitzii (Bromeliaceae), a species from the Southern Brazilian Highlands

Abstract The Southern Brazilian Highlands are composed by a mosaic of Mixed Ombrophilous Forest (MOF) and grassland formations, an interesting landscape for the study of population structure. We analyzed the genetic diversity within and among populations of the MOF-endemic bromeliad Vriesea reitzii by genotyping seven nuclear microsatellite loci in 187 individuals from six populations. We characterized levels of genetic diversity and assessed the genetic structure among populations. Vriesea reitzii populations showed high levels of genetic variation (number of alleles 28 - 43, allelic richness 3.589 - 5.531) and moderate levels of genetic differentiation (FST = 0.123, RST = 0.096). The high levels of genetic diversity may be explained by species life-history traits, such as habit and mating system. The moderate structure may be a product of the combination of ancient and contemporary gene flow, resulting from the expansion of the forest in the Holocene, and/or due to facilitated dispersal mediated by the MOF's mosaic landscape. The genetic results indicated no imminent threat to this bromeliad. However, the species is highly associated with the MOF, putting landscape conservation at the center of conservation efforts for the species' maintenance.