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.

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.

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.

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.

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.

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.

Fast monitoring of tooth erosion caused by medicaments used in the treatment of respiratory diseases by ATR-FTIR and µ-EDXRF analysis.

The present study aimed to evaluate the erosive potential of four most commonly prescribed syrup medicaments for respiratory diseases. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy combined with multivariate statistical analysis and micro-energy-dispersive X-ray fluorescence spectrometry (µ-EDXRF) mapping was performed. Fifty-five root dentin fragments obtained from the buccal surface of 30 bovine teeth were prepared and divided into five experimental groups (n = 10): control-artificial saliva (S), acebrofilin hydrochloride (AC), ambroxol hydrochloride (AM), bromhexine hydrochloride (BR), and salbutamol sulfate (SS). The S group was stored only in artificial saliva and the other groups were treated with the medicaments (immersed for 1 min in 3 mL of the medication, three times daily, with 1-h intervals between the immersion cycles, during 5 days, 15 immersion cycles). There were a significant decrease in the Ca and P weight percentages (wt%) for dentin after medication treatments, except for AC (p > 0.05). Mineral content of dentin showed a clear gradation with increasing Ca and P wt% reduction in the order S < AC < AM < BR < SS. SS resulted in a significant increase in Ca/P ratio when compared to the control (p < 0.001). ATR-FTIR combined with multivariate, statistical analysis can quickly and reliably indicate extent of dentin erosion. Considering syrups with high-erosive potential should always follow with proper oral hygiene practices or search for an alternative medications void of such detrimental effects. Regular and prolonged use of these medicaments might bear the risk of causing erosion.

Multi-walled carbon nanotubes/graphene oxide hybrid and nanohydroxyapatite composite: A novel coating to prevent dentin erosion.

To date is emergent the development of novel coatings to protect erosion, especially to preventive dentistry and restorative dentistry. Here, for the first time we report the effectiveness of multi-walled carbon nanotube/graphene oxide hybrid carbon-base material (MWCNTO-GO) combined with nanohydroxyapatite (nHAp) as a protective coating for dentin erosion. Fourier transform Raman spectroscopy (FT-Raman), scanning electron (SEM), and transmission electron (TEM) microscopy were used to investigated the coatings and the effect of acidulated phosphate fluoride gel (APF) treatment on bovine teeth root dentin before and after erosion. The electrochemical corrosion performance of the coating was evaluated. Raman spectra identified that: (i) the phosphate (ν1PO43-) content of dentin was not significantly affected by the treatments and (ii) the carbonate (ν1CO32-) content in dentin increased when nHAp was used. However, the nHAp/MWCNTO-GO composite exposited lower levels of organic matrix (CH bonds) after erosion compared to other treatments. Interesting, SEM micrographs identified that the nHAp/MWCNTO-GO formed layers after erosive cycling when associate with APF treatment, indicating a possible chemical bond among them. Treatments of root dentin with nHAp, MWCNTO-GO, APF_MWCNTO-GO, and APF_nHAp/MWCNTO-GO increased the carbonate content, carbonate/phosphate ratio, and organic matrix band area after erosion. The potentiodynamic polarization curves and Nyquist plot showed that nHAp, MWCNT-GO and nHAp/MWCNT-GO composites acted as protective agents against corrosion process. Clearly, the nHAp/MWCNTO-GO composite was stable after erosive cycling and a thin and acid-resistant film was formed when associated to APF treatment.

Molecular and morphological surface analysis: effect of filling pastes and cleaning agents on root dentin.

OBJECTIVE: This study evaluated the effect of different filling pastes and cleaning agents on the root dentin of primary teeth using Fourier-transformed Raman spectroscopy (FT-Raman), micro energy-dispersive X-ray fluorescence (µ-EDXRF) and scanning electron microscopic (SEM) analysis. MATERIAL AND METHODS: Eighty roots of primary teeth were endodontically prepared and distributed into 4 groups and filled according to the following filling pastes: Control-no filling (CP), Calen®+zinc oxide (CZ), Calcipex II® (CII), Vitapex® (V). After seven days, filling paste groups were distributed to 4 subgroups according to cleaning agents (n=5): Control-no cleaning (C), Ethanol (E), Tergenform® (T), 35% Phosphoric acid (PA). Then, the roots were sectioned and the dentin root sections were internally evaluated by FT-Raman, µ-EDXRF and SEM. Data was submitted to two-way ANOVA and Tukey tests (α=0.05). RESULTS: Regarding filling pastes, there was no significant difference in organic content. CP provided the lowest calcium values and, calcium/phosphoric ratio (Ca/P), and the highest phosphoric values. For cleaning agents there was no difference in organic content when compared to the C; however, T showed significantly higher calcium and Ca/P than PA. All groups showed similar results for phosphorus. The dentin smear layer was present after use of the cleaning agents, except PA. CONCLUSION: The filling pastes changed the inorganic content, however they did not change the organic content. Cleaning agents did not alter the inorganic and organic content. PA cleaned and opened dentin tubules.

Molecular and morphological surface analysis: effect of filling pastes and cleaning agents on root dentin

Abstract The quality of the dentin root is the most important factor for restoration resin sealing and drives the outcome of endodontic treatment. Objective This study evaluated the effect of different filling pastes and cleaning agents on the root dentin of primary teeth using Fourier-transformed Raman spectroscopy (FT-Raman), micro energy-dispersive X-ray fluorescence (µ-EDXRF) and scanning electron microscopic (SEM) analysis. Material and Methods Eighty roots of primary teeth were endodontically prepared and distributed into 4 groups and filled according to the following filling pastes: Control-no filling (CP), Calen®+zinc oxide (CZ), Calcipex II® (CII), Vitapex® (V). After seven days, filling paste groups were distributed to 4 subgroups according to cleaning agents (n=5): Control-no cleaning (C), Ethanol (E), Tergenform® (T), 35% Phosphoric acid (PA). Then, the roots were sectioned and the dentin root sections were internally evaluated by FT-Raman, µ-EDXRF and SEM. Data was submitted to two-way ANOVA and Tukey tests (α=0.05). Results Regarding filling pastes, there was no significant difference in organic content. CP provided the lowest calcium values and, calcium/phosphoric ratio (Ca/P), and the highest phosphoric values. For cleaning agents there was no difference in organic content when compared to the C; however, T showed significantly higher calcium and Ca/P than PA. All groups showed similar results for phosphorus. The dentin smear layer was present after use of the cleaning agents, except PA. Conclusion The filling pastes changed the inorganic content, however they did not change the organic content. Cleaning agents did not alter the inorganic and organic content. PA cleaned and opened dentin tubules.

Fluorescence spectroscopy of teeth and bones of rats to assess demineralization: In vitro, in vivo and ex vivo studies.

This study investigated the effects of demineralization on teeth and bones evaluated by fluorescence spectroscopy and micro energy-dispersive X-ray fluorescence spectrometry (µ-EDXRF) in rats. For in vitro study, 20 teeth of Wistar rats were removed and decalcified to evaluate fluorescence. For in vivo study, 10 female Wistar rats aged 6months were randomized into 2 groups: Control Group (C): non-ovariectomized rats; Ovariectomy Group (OV): ovariectomized rats to induce osteoporosis. The fluorescence spectroscopy of the teeth was performed for long-term (until 180days). For ex vivo study, the tooth and femur bone of the Wistar rats were removed at 180days to perform fluorescence spectroscopy using excitation laser at 408 and 532nm and µ-EDXRF for calcium (Ca) and phosphorus (P) analysis. There were no intergroup differences in fluorescence spectra with laser at 408nm (p≥0.05), but there were changes in the fluorescence spectra using laser at 532nm which led to both the wavelength shift and changes in the band area (p<0.05). The concentrations of P and Ca for the dentine and cortical bone, respectively, were significantly reduced in OV (p<0.05). Demineralization leading to loss of tissue quality may be assessed by fluorescence spectroscopy using 532nm laser. These findings corroborate those obtained by µ-EDXRF.

The effects of acid erosion and remineralization on enamel and three different dental materials: FT-Raman spectroscopy and scanning electron microscopy analysis.

OBJECTIVES: FT-Raman spectroscopy and scanning electron microscopy (SEM) were employed to test the hypothesis that the beverage consumption or mouthwash utilization would change the chemistry of dental materials and enamel inorganic content. MATERIAL AND METHODS: Bovine enamel samples (n = 36) each received two cavity preparations (n = 72), each pair filled with one of three dental materials (R: nanofilled composite resin, GIC: glass-ionomer cement, RMGIC: resin-modified GIC). Furthermore, they were treated with three different solutions (S: artificial saliva, E: erosion/Pepsi Twist or EM: erosion + mouthwash/Colgate Plax). RESULTS: Reduction of carbonate content of enamel was greater in RE than RS (P < 0.01). Increment of carbonate was greater in GICEM than in GICE and GICS (P < 0.01; P < 0.001). Significant material degradation was found in RE, REM, GICE, and GICEM than in RS and GICS (P < 0.01; P < 0.001). SEM showed clear enamel demineralization after erosion. Material degradation was greater after E and EM than S. GIC and RMGIC materials had a positive effect against acid erosion in the adjacent enamel after remineralization with mouthwash. CONCLUSIONS: The beverage and mouthwash utilization would change R and GIC chemical properties. CLINICAL RELEVANCE: A professional should periodically monitor the glass-ionomer and resin restorations, as they degrade over time under erosive challenges and mouthwash utilization. Microsc. Res. Tech., 2016. © 2016 Wiley Periodicals, Inc. Microsc. Res. Tech. 79:646-656, 2016. © 2016 Wiley Periodicals, Inc.

Effect of therapeutic doses of radiotherapy on the organic and inorganic contents of the deciduous enamel: an in vitro study.

OBJECTIVES: This study evaluated the effects of radiotherapy on the composition of deciduous teeth enamel using micro-energy-dispersive X-ray fluorescence and Fourier transform Raman spectroscopy before and after a pH cycling process. MATERIALS AND METHODS: Ten deciduous molars were sectioned and divided into two groups (n = 10). The radiotherapy group (RT) was irradiated with 54 Gy at 2 Gy/day, 5 days per week for 5 weeks and 2 days, and the normal group (N) was not irradiated. The RT group was evaluated before radiotherapy (RTb), after radiotherapy (RTa), and after radiotherapy and pH cycling (RTc). The normal group was evaluated before (N) and after pH cycling (Nc). The weight percentage (wt%) of calcium (Ca), phosphorus (P), and organic content; the Ca/P ratio; and the integrated area of the Raman bands relative to the organic, carbonate, and phosphate contents were also evaluated. RESULTS: The exclusive use of RT reduced the organic content of the enamel (p = 0.000). The RTc group exhibited a decrease in P wt% (p = 0.016), an increase in the Ca/P ratio (p = 0.000), and a reduction in the integrated area of the phosphate band (p = 0.046). An increase in the Ca/P ratio (p = 0.000) and a reduction in the areas of the carbonate and phosphate bands were found in the RTb/RTc treatments. CONCLUSIONS: RT application at a therapeutic dose reduced the organic content of the deciduous enamel. CLINICAL RELEVANCE: Preventive measures should be included in the patient treatment protocol because of RT-induced chemical changes to the deciduous enamel.