Bovine Enamel Research Articles

Physical-Mechanical Properties and Mineral Deposition of a Pit-and-Fissure Sealant Containing Niobium-Fluoride Nanoparticles-An In Vitro Study.

This study investigated the combined effects of adding niobium-fluoride (NbF5) nanoparticles to a pit-and-fissure sealant. One resin sealant was reinforced with varying amounts of nanoparticles (0.3, 0.6, and 0.9 wt%). The surface hardness (SH), energy-dispersive X-ray spectroscopy (EDX), surface roughness (Ra), color change (ΔE), and mineral deposition were assessed. Bovine enamel blocks were subjected to demineralization and pH-cycling for SH. The elemental composition and Ca/P ratio were evaluated using EDX, while the mineral deposition was measured using Fourier transform infrared spectroscopy (FTIR). Data were analyzed using ANOVA and Tukey's test for the SH and EDX, ΔE, and Kruskal-Wallis for the Ra. The NbF5 modification increased the SH, with the 0.9 wt% sealant exhibiting higher SH values, and the 0.3 wt% one exhibiting significant differences compared to the control and the 0.9 wt% (p = 0.00) samples, even after pH-cycling. For the EDX analysis, the 0.3 and 0.6 wt% samples exhibited higher Ca/P ratios, with the 0.3% one showing evidence of P-O crystal formation. There was no significant difference in the Ra (p = 0.458), and the 0.6 and 0.9 wt% ones showed lower ΔE values compared to the control. The 0.3 wt% NbF5 demonstrated improved overall properties, making these results particularly promising for preventing tooth decay, reducing demineralization through increased ions release and promoting remineralization in posterior teeth.

Bacterial Adhesion and In Situ Biodegradation of Preheated Resin Composite Used as a Luting Agent for Indirect Restorations.

To evaluate surface roughness and bacterial adhesion after in situ biodegradation of the cementation interface of indirect restorations cemented with preheated resin composite. Resin composite blocks (Z250XT/3M ESPE) were cemented to bovine enamel (7 × 2.5 × 2 mm) using preheated microhybrid resin composites: (1) Filtek Z100 (3M ESPE) (Z100); (2) Gradia Direct X (GC America) (GDX); and (3) Light-cured resin cement RelyX Veneer (3M ESPE) (RXV) (n = 21). The resin composites were preheated on a heating device (HotSet, Technolife) at 69°C for 30 minutes. Disk-shaped specimens (7 x 1.5 mm) were made for biodegradation analysis with the luting agents (n = 25). The in situ phase consisted of 20 volunteers' using an intraoral palatal device for 7 days. Each device had six cylindrical wells for the blocks and the disk-shaped specimens. Biodegradation was evaluated through surface roughness (Ra), scanning electron microscopy (SEM) micromorphological analysis, and colony-forming unit (CFU) count. The film thickness of the luting agents was also measured under stereomicroscopy. Increased surface roughness was observed after the cariogenic challenge without differences between the luting agents. Higher variation and surface flaws suggestive of particulate detachment were observed for Z100. No differences were observed in CFU counts. All materials underwent surface biodegradation, and the surface roughness of the resin cements was similar to or lower than that of the preheated resin composites. The resin composites' film thickness was thicker than that of the resin cement. Clinicians should be aware of these factors when choosing the use of preheated resin composite since it can lead to reduced longevity of the cementation interface and, therefore, restorations.

Biofilm modulation and demineralization reduction after treatment with a new toothpaste formulation containing fluoride, casein phosphopeptide-amorphous calcium phosphate, and sodium trimetaphosphate: In situ study

ObjectiveThis in situ study aimed to evaluate a new toothpaste formulation containing fluoride (F), casein phosphopeptide amorphous calcium phosphate (CPP-ACP) and sodium trimetaphosphate (TMP) on the process of dental demineralization and biofilm composition. MethodsThis crossover double-blind study consisted of five phases, in which 10 volunteers wore intraoral appliances containing four bovine enamel specimens. The cariogenic challenge was performed using 30 % sucrose solution. Blocks were treated 3 ×/day with the following toothpastes: 1) Placebo (No F-TMP-CPP-ACP), 2) 1100 ppm F (1100F), 3) 1100F + 3 %TMP (1100F-TMP), 4) 1100F + 10 %CPP-ACP (1100F-CPP-ACP) and 5) 1100F-CPP-ACP-TMP. After 7 days, the percentage loss of surface hardness (%SH), integrated loss of subsurface hardness (ΔKHN), F, calcium (Ca) and phosphorus (P) concentration in the enamel was determined. The concentration of F, Ca, P and insoluble extracellular polysaccharide (EPS) in the biofilm were analyzed. ResultsThe addition of CPP-ACP-TMP to 1100F reduced %SH by 42 % and 39 % when compared to the 1100F and 1100F-CPP-ACP (p < 0.001); in addition, to a reduction in lesion body (ΔKHN) by 36 % for the same treatments. The treatment with 1100F-CPP-ACP-TMP led to a significant increase in the concentration of F, P and Ca in the enamel and biofilm, and reduced the concentration of EPS (p < 0.001). SignificanceToothpaste formulation containing 1100F-CPP-ACP-TMP prevented the reduction of enamel hardness and significantly influenced the ionic biochemical composition and insoluble extracellular polysaccharide (EPS) in biofilm formed in situ. These results are promising and provide valuable insights for the design of further clinical trials.

Effects of Dentifrices With Antierosive Potential on the Surface of Bovine Enamel Submitted to Acidic Beverage.

To evaluate the effects of dentifrices containing sodium fluoride (NaF) combined with NovaMin (Sensodyne Repair & Protect-SRP), NaF combined with stannous fluoride (SnF2, Oral-B Pro-Gengiva-OBP), and amine fluoride (AmF, Colgate Elmex-ELM) on enamel subjected to simulated erosive cycling. Bovine enamel-dentin discs (n = 10/group) were subjected to erosive cycling with orange juice (pH = 3.29, 5 min, 3x/day), artificial saliva (SA-2 h, 3x/day and overnight) and treated with dentifrice (2 min, 2x/day) or without treatment (CONT). Surface microhardness (SMH) was evaluated at baseline (T0), on the first (T1) and fifth (T5) days. SMH loss (%SHL) was calculated. Surface roughness (Ra, μm) was determined at T0 and T5. Morphology and mineral content were evaluated under scanning electron microscopy and energy-dispersive x-ray spectroscopy. Data were analyzed using ANOVA/Tukey or Bonferroni (α = 5%). No differences in %SHL were detected among groups at T1. At T5, OBP promoted %SHL, Ra, and ΔRa significantly lower than all the other groups (p < 0.05). All groups exhibited morphological changes in topography and similar Ca/P means before and after treatments. Dentifrice containing SnF2 minimized the negative effects on the SMH and Ra caused by exposure to orange juice after 5 days of simulated cycling. Patients who are more exposed to risk factors for dental erosion could benefit from the use of dentifrice containing SnF2.

Effect of combining aminomethacrylate and fluoride against erosive and abrasive challenges on enamel and dentin.

This study evaluated the effect of solutions containing aminomethacrylate copolymer (AA) and sodium fluoride (F; 225ppm F-) or fluoride plus stannous chloride (FSn; 225ppm F-, 800ppm Sn2+) against enamel and dentin erosion/abrasion. Solutions F, FSn, AA, F+AA, FSn+AA, and deionized water as negative control were tested. Bovine enamel and dentin specimens (n=13/solution/substrate) underwent a set of erosion-abrasion cycles (0.3% citric acid [5min, 4×/day], human saliva [1h, 4×/day], brushing [15 s, 2×/day], and treatments [2min, 2×/day]) for each of five days. Initial enamel erosion was evaluated using Knoop microhardness after the first and second acid challenge on day 1, and surface loss with profilometry after day 5. KOH-soluble fluoride was assessed. Data were analyzed with ANOVA/Tukey tests. The combination of fluoride and AA resulted in higher protection against enamel erosion, whereas this was not the case for the combination of AA and FSn. All treatments protected against enamel and dentin loss. The lowest surface loss values were observed with F+AA and FSn+AA. The polymer did not significantly influence the KOH-soluble fluoride formation on enamel/dentin specimens. The aminomethacrylate copolymer effectively enhanced the efficacy of sodium fluoride against initial erosion and improved the control of enamel and dentin wear of F and FSn solutions.

Effects of tea and coffee on tooth discoloration

Tooth discoloration because of dietary habits is a serious concern, particularly from tea and coffee consumption. This study investigated the effects of these beverages on tooth discoloration, focusing on their key chemical components. Bovine enamel specimens were immersed in green and black tea samples and Arabica and Robusta coffee samples for 1–72 h. High-performance liquid chromatography analyzed catechins, theaflavins, and chlorogenic acids, while spectrophotometry measured discoloration. Multiple regression analysis (significance at p &lt; 0.05) revealed that all beverages caused significant tooth discoloration, with black tea showing the most pronounced effect because of its theaflavin content.

Evaluation of Enamel Surface Properties Submitted to Bleaching With 35% Hydrogen Peroxide Associated With Titanium Tetrafluoride (TiF4).

This study evaluated the color change, surface roughness, mineral content and morphology of enamel bleached with 35% hydrogen peroxide (HP) combined with an experimental gel containing 1% titanium tetrafluoride (TiF4). Bovine enamel blocks were treated with (n = 12): (TiF) experimental gel containing 1% TiF4, (HP) 35% HP, (HPT) 35% HP + 1% TiF4and (CT) control. Bleaching with HP was performed in 3 sessions (3 × 15 min/applications). pH, colorimetric parameters, surface roughness, mineral content and enamel morphology were determined. The pH was evaluated for 45 min. The color parameters were determined before bleaching (T0), and 14 days elapsed from the last bleaching session (T4). Surface roughness was analyzed at T0 and immediately after last bleaching session (T3). Enamel mineral content and morphology were verified at T4. Data were statistically analyzed by one-way, two-way ANOVA and Kruskal-Wallis (α = 0.05). TiF increased surface roughness, and no differences between HP and HPT in terms of color and - mineral content. Ti was detected only on TiF, and slight surface morphology changes were observed in bleached enamel. The combination of TiF4 and 35% HP did not interfere with the enamel bleaching effect, controlled surface roughness, and kept mineral content but promoted a minor surface morphology alteration. Due to the adverse effects of bleaching, titanium tetrafluoride (TiF4) has gained attention for its therapeutic properties, including the ability to reverse mineral loss and neutralize remineralization of mineral structures. Therefore, TiF4's remineralizing capacitymay be a good alternative for incorporation into hydrogen peroxide bleaching agents.

Evaluation of REFIX Technology on the Remineralization of Artificial Early Enamel Caries Lesion by Laser Speckle Tracking Analysis.

To assess the effectiveness of the REFIX technology in the remineralization process of initial caries simulated on bovine enamel. The assessment involved the analysis of backscatter intensity, which was determined from laser speckle images. Twenty-one bovine teeth were divided into three groups: G1 and G7 were submitted to treatment with the REFIX technology for 1 and 7 days, respectively. The control group was treated with deionized water. A significant difference in backscatter was found between the carious and sound areas in all groups (p = 0.0038, p < 0.0001, and p = 0.0002 for the control group, G1, and G7, respectively). The intergroup comparison revealed no significant difference among the groups studied. REFIX technology did not alter the optical properties of the samples of bovine teeth with simulated initial caries lesions after 1 and 7 days of treatment.

Influence of Surface Pretreatment on the Bond Strength of a Resin Luting Cement to Saliva-contaminated Enamel and Dentin.

This study aimed to evaluate the influence of surface pretreatment on the shear bond strength (SBS) of a resin luting cement to enamel and dentin with saliva contamination. The surface free energies (SFE) of the adherent surfaces were also determined. Bovine enamel and dentin were used in this study. For the saliva-contamination, human saliva was applied to the adherent surface for 60 seconds and then air-dried, and the specimens without saliva contamination served as controls. One group of contaminated surfaces was untreated (SC), and the others were pretreated with Katana Cleaner (KC), Multi Etchant (ME), or Ultra-Etch (UE). Fifteen specimens were prepared to measure the SBS for each test group.The mixed resin luting cement paste was applied to the alumina-blasted surface of a stainless-steel rod and placed on the prepared tooth surface. The luting cement was light irradiated for 40 seconds. The bonded specimens were stored for 24 hours at 37°C and half of the bonded specimens underwent 10,000 thermal cycles. The SBS and SFE of the specimens after different pre-treatments were measured. The two-way ANOVA revealed that the factors of pretreatment agent and storage condition had a significant effect on the SBS to enamel and dentin. The SFE values of the SC group were significantly lower than those of the other groups in both enamel and dentin. The SFE of pretreated surface was material dependent. A pretreatment agent containing functional monomers was shown to be effective in removing saliva contaminants and in creating an effective bonding surface for the resin luting cement.

A label-free quantification method for assessing sex from modern and ancient bovine tooth enamel

Identification of the sex of modern, fossil and archaeological animal remains offers many insights into their demography, mortality profiles and domestication pathways. However, due to many-factors, sex determination of osteological remains is often problematic. To overcome this, we have developed an innovative protocol to determine an animal’s sex from tooth enamel, by applying label-free quantification (LFQ) of two unique AmelY peptides ‘LRYPYP’ (AmelY;[M+2]2+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{2+}$$\\end{document} 404.7212 m/z) and ‘LRYPYPSY’ (AmelY;[M+2]2+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{2+}$$\\end{document} 529.7689 m/z) that are only present in the enamel of males. We applied this method to eight modern cattle (Bos taurus) of known sex, and correctly assigned them to sex. We then applied the same protocol to twelve archaeological Bos teeth from the Neolithic site of Beisamoun, Israel (8-th–7-th millennium BC) and determined the sex of the archaeological samples. Since teeth are usually better preserved than bones, this innovative protocol has potential to facilitate sex determination in ancient and modern bovine remains that currently cannot be sexed.

Lacticaseibacillus rhamnosus inhibits the development of dental caries in rat caries model and in vitro

ObjectivesDental caries result from a microbial imbalance in the oral cavity. Probiotics ecologically modulate the oral microflora to prevent caries. This study evaluated the anti-cariogenic effects of two Lacticaseibacillus rhamnosus strains in vitro and in vivo to provide a more theoretical basis for its clinical applications in caries prevention. MethodsIn the study, cariogenic biofilms were grown with L. rhamnosus (LGG) or L. rhamnosus ATCC 7469 and analyzed. Quantitative real-time PCR (qPCR), Scanning Electron Microscope (SEM), and Confocal laser scanning microscope (CLSM) were used to detect the changes in the composition and architectures; cariogenic activity was measured by the lactic acid production and Transverse Microradiography (TMR). The effects of LGG on the 12 Sprague-Dawley rat caries model were assessed using Keyes scores and micro-CT analysis. Oral microbiome changes were evaluated through 16S rRNA gene high-throughput sequencing. ResultsL. rhamnosus can reduce cariogenic bacteria in biofilm by 14.7 % to 48.9 %, with LGG exhibiting more potent inhibitory effects. Both strains of L. rhamnosus can adhere to the surface of biofilms, reduce the extracellular polysaccharides (EPS) matrix, and loosen the biofilm structure. L. rhamnosus inhibited cariogenic activity by reducing the lactic acid production in biofilms. The bovine enamel blocks presented lower mineral loss values and lesion depth values in the group Core+L.rh and Core+LGG. LGG-ingested rats had significantly lower levels of moderate dentin lesions and higher mineral density than the control group. The 16 s rRNA gene sequencing revealed that LGG regulated the beta diversity of the oral microbial community in the rat dental caries model. ConclusionsThis study revealed the promising potential of L. rhamnosus, especially the LGG strain, in the ecological prevention of dental caries. Clinical SignificanceProbiotics may provide a strategy for preventing caries by regulating the oral microecological balance. The study revealed the promising anti-caries potential of the LGG probiotic strain in vivo and in vitro. It is expected that LGG could be used as an oral probiotic for the clinical prevention and treatment of caries.

Effect of enamel deproteinization with 5.25% sodium hypochlorite on the bond strength of orthodontic brackets. An experimental study.

In the search for alternatives to increase the bond strength of brackets, when necessary, this study proposes to apply the enamel deproteinization protocol to eliminate the proteins in the surface enamel to achieve better etching patterns and thereby increase bond strength. The aim of this study was to evaluate the effect of sodium hypochlorite as a deproteinizing agent on the bond strength of metal brackets. Forty bovine teeth were randomly and equally divided into two groups. The experimental group (n=20) underwent a deproteinization treatment with sodium hypochlorite at 5.25% for 60 seconds prior to acid etching of the enamel with 37% phosphoric acid and bracket bonding with Transbond XTTM resin. The control group (n=20) underwent enamel etching with 37% phosphoric acid and bracket bonding with Transbond XTTM resin. Shear strength and the adhesive remnant index were evaluated and the Students t and Chi-square tests were used (P<0.05). The bond strength values of the control group (27.72±6.42 Mpa) were not significantly lower compared to the experimental group (29.21± 7.96 Mpa) (p=0.259). The adhesive remnant index showed a similar behavior in both groups, with the amount of adhesive remaining on the enamel being less than 50% in most samples of both the control and experimental group. Deproteinization treatment of bovine tooth enamel with 5.25% sodium hypochlorite for 60 seconds prior to enamel acid etching does not improve the bond strength of a resin in orthodontic bracket bonding. Key words:Deproteinization, sodium hypochlorite, bracket bonding, orthodontics.

Assessment of the effect of experimental gel of pregabalin associated with 35% hydrogen peroxide bleaching on bovine dental enamel: an in vitro study.

To assess the effect of bleaching with gel of pregabalin associated with 35% hydrogen peroxide on the mechanical and chemical properties and ultramorphology of dental enamel. Thirty-six (36) specimens of bovine dental incisors were obtained and divided into three groups (n = 12), namely: CG = bleaching with 35% hydrogen peroxide; KFG = bleaching with 5% potassium nitrate and 2% sodium fluoride gel + 35% hydrogen peroxide; and PGG = bleaching with experimental gel of pregabalin + 35% hydrogen peroxide. The specimens were assessed with respect to Knoop microhardness, surface roughness, and colour change, before and after bleaching. They were also assessed using scanning electron microscopy and energy-dispersive spectroscopy after treatments. All groups exhibited an increase in surface roughness and a reduction in Knoop microhardness after the protocols. There was colour change in all groups, with no difference between them. In addition, there were changes in enamel morphology and non-significant loss of calcium and phosphorus. The experimental gel of pregabalin did not influence the action of 35% hydrogen peroxide, yielding results similar to those of the other groups assessed in all the parameters. Therefore, the gel of pregabalin can be an alternative for topical application on the surfaces of the teeth in association with bleaching treatments.

The damage and remineralization strategies of dental hard tissues following radiotherapy

ObjectivesThis study pursued two main purposes. The first aim was to expound on the microscopic factors of radiation-related caries (RRC). Further, it aimed to compare the remineralization effect of different remineralizing agents on demineralized teeth after radiotherapy.MethodsThe enamel and dentin samples of bovine teeth were irradiated with different doses of radiation. After analysis of scanning electron microscope (SEM), X-Ray diffraction (XRD), and energy dispersive spectrometer (EDS), the samples irradiated with 50 Gy radiation were selected and divided into the demineralization group, the double distilled water (DDW) group, the Sodium fluoride (NaF) group, the Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) group, the NaF + CPP-ACP group, and the Titanium tetrafluoride (TiF4) group. After demineralization, remineralizing agents treatment, and remineralization, the samples were evaluated using SEM, atomic force microscope (AFM), EDS, and transverse microradiography (TMR).ResultsA radiation dose of 30 Gy was sufficient to cause damage to the dentinal tubules, but 70 Gy radiation had little effect on the microstructure of enamel. Additionally, the NaF + CPP-ACP group and the TiF4 group significantly promoted deposit formation, decreased surface roughness, and reduced mineral loss and lesion depth of demineralized enamel and dentin samples after radiation.ConclusionsRadiation causes more significant damage to dentin compared to enamel. NaF + CPP-ACP and TiF4 had a promising ability to promote remineralization of irradiated dental hard tissues.Advances in knowledgeThis in vitro study contributes to determining a safer radiation dose range for teeth and identifying the most effective remineralization approach for RRC.

Effect of multi-layer applications of self-etch universal bonding agents on the adhesion of resin composite to enamel.

To evaluate the effect of adhesive coats application on the enamel microtensile bond strength (µTBS) of universal adhesives, morphological etching pattern and their chemical interaction with hydroxyapatite (HA). Two universal adhesives were investigated: Scotchbond Universal (SBU, 3M) and Prime&Bond Universal (PBU, Dentsply). The adhesives were applied in self-etching mode on bovine enamel (n = 8) in one (1L), two (2L) or three coats (3L) and light-cured as per manufacturers' instructions. As controls adhesives were applied to etched enamel (H3PO4-37% phosphoric acid). Bonded specimens were cut into sticks that were stored in deionized water for 24h or 6months prior to µTBS testing. Two-way ANOVA and Tukey's test were used for statistical analysis of bond strength with α = 5%. For morphological SEM analysis, enamel surfaces were treated as aforementioned and immediately rinsed with acetone. The intensity of monomer-calcium salt formation from each treatment was measured via infrared spectroscopy (ATR-FTIR). All treatments presented no significant reduction on µTBS after aging (p > 0.05). However, SBU attained highest µTBS when applied in 3L. PBU showed higher µTBS when applied to H3PO4 etched enamel than 1L or 2L. Etching pattern was enhanced by 3L application, particularly with PBU. Chemical interaction was notably higher for SBU than PBU, with no relevant differences with more layers or prior H3PO4-etching. The application of three adhesive coats of universal adhesives in self-etch mode using may enhance the bonding performance and etching pattern to enamel, surpassing the H3PO4-etched enamel bond for SBU. The chemical interaction with calcium from enamel is not affected by number of coats or prior phosphoric acid etching.

Activity of Fluoride Varnishes Containing Micrometric or Nanosized Sodium Trimetaphosphate against Early Enamel Erosive Lesions In Vitro

This study aimed to assess the effects of fluoridated varnishes supplemented with micrometric or nanosized sodium trimetaphosphate (TMPmicro or TMPnano, respectively) against enamel softening in an early erosive model in vitro. Bovine enamel blocks (with mean surface hardness [SH] between 330.0 and 380.0 kgf/mm2) were selected and randomly assigned according to their SH (n = 8) into the following groups: Placebo (no fluoride/TMP; negative control), 5% NaF (positive control), 5% NaF + 5%TMPmicro, 5% NaF + 2.5%TMPnano and 5% NaF + 5%TMPnano. Blocks received a single application of the varnishes and were immersed in artificial saliva (6 h). Thereafter, the varnishes were removed and the blocks were subjected to four individual erosive challenges (1 min, citric acid, 0.75%, pH = 3.5, under agitation); SH was determined after each challenge. Data were subjected to ANOVA and Student–Newman–Keuls’ test (p &lt; 0.05). Overall, the highest %SH loss was observed for the Placebo, followed by 5% NaF, 5% NaF + 5% TMPmicro, and both varnishes containing TMPnano, without significant differences between 2.5% and 5% TMPnano. It was concluded that TMP enhanced the effects of a 5% NaF varnish against enamel softening in an early erosive model in vitro, with an additional benefit from the use of nanoparticles over microparticles.

Adhesive Performance of Pit and Fissure Sealants on Deproteinized Enamel with Different Proteolytic Agents: In Vitro Study.

The objective of this work was to assess the efficacy of different proteolytic agents on the bond strength of pit and fissure sealants to bovine enamel. Eighty-four bovine enamel specimens were randomly assigned in groups according to the pit and fissure sealant applied (HelioSeal F or Dyad Flow). Then, the specimens were subdivided according to the proteolytic agent used (n = 7): Group 1, distilled water (control); Group 2, 10 wt.% Tergazyme®; Group 3, 10 wt.% ZYME®; Group 4, 10% papain gel; Group 5, 10% bromelain gel; and Group 6, 5.25 wt.% sodium hypochlorite. The cell viability of the proteolytic solutions was assessed through the MTT assay. The proteolytic agents were applied on the enamel surface prior to the acid-etching procedure; then, the pit and fissure sealants were placed. The micro-shear bond strength was evaluated after 24 h or 6 months of water storing at 37 °C. Representative SEM images were taken for each experimental group. The bond strength data were statistically analyzed by a three-way ANOVA test using a significance level of α = 0.05. Bromelain and papain proteolytic solutions did not exert any cytotoxic effect on the human dental pulp cells. After 24 h and 6 months of aging, for both pit and fissure sealants, sodium hypochlorite, papain, bromelain, and Tergazyme® achieved statistically significant higher bond strength values (p < 0.05). Irrespective of the deproteinizing agent used, Dyad Flow resulted in a better bond strength after 6 months of aging. The type 1 etching pattern was identified for sodium hypochlorite, papain, and bromelain. Tergazyme®, papain, and bromelain demonstrated efficacy in deproteinizing enamel surfaces prior to acid etching, leading to the improved bond strength of pit and fissure sealants. Clinically, this suggests that these proteolytic agents can be considered viable alternatives to traditional methods for enhancing sealant retention and longevity. Utilizing these agents in dental practice could potentially reduce sealant failures.

Inorganic Phosphate Effect in a Hydrogen Peroxide-based Bleaching Agent: Physicochemical, Mechanical, and Morphological Properties of Dental Enamel.

This in vitro study aimed to assess the impact of incorporating calcium glycerophosphate (CaGP) and sodium fluoride (NaF) in addition to 35% hydrogen peroxide concerning the enamel mechanical and morphological properties. Specimens of bovine enamel were chosen based on their initial surface hardness (SHi) and subsequently divided into five gel groups (n=12): 1) 35% Hydrogen Peroxide (HP) Gel; 2) HP + 0.1% NaF Gel (HP/NaF); 3) HP + 0.25% CaGP Gel (HP/CaGP); 4) HP + 0.1% NaF + 0.25% CaGP Gel (HP/NaF/CaGP) and 5) HP Blue 35% Gel (HP Blue). The bleaching gels were applied thrice, for 40 min, at intervals of 7 days each. After 21 days, the final surface hardness (SHf), integrated hardness (IH), Polydispersity Index (PdI) and Zeta Potential (Zp), surface roughness (Ra, after and before), and surface/structural analysis by Scanning Electron Microscopy (SEM) were determined. The data were submitted to ANOVA (one-way and two-way) followed by the Student-Newman-Keuls test (α=0.05). The addition of NaF to HP reduced demineralization by 11.5% in relation to HP (p<0.05). The NaF/CaGP association reduction is 22.8 and 20% higher in comparison to HP/NaF/CaGP and HP Blue, respectively. The IH when the PH/NaF/CaGP bleaching gel was applied, was 14% higher compared to HP and HP Blue groups. It can be concluded that the association of NaF and CaGP with the 35% hydrogen peroxide gel (HP/NaF/CaGP) significantly changed tooth enamel demineralization in terms of surface, depth, roughness, and enamel morphology.

Development and effect of orodispersible film incorporated with Biosilicate for remineralization of dental enamel subjected to cariogenic and erosive challenge.

The objective of this in vitro study was to assess the efficiency of incorporating Biosilicate particles (30 and 50 mg) into an experimental orodispersible film and its efficacy in the remineralization process of bovine dental enamel under cariogenic and erosive challenges. Ninety-nine intact incisors, devoid of cracks or fractures, yielding 198 samples (6 × 6 × 2 mm) via vestibular sectioning using a low-speed diamond disc under water cooling. After flattening the enamel surface with 600, 1200, and 2000 grit sandpaper, the samples were divided into two groups based on the challenges they underwent: cariogenic (0.1 M lactic acid at pH 5.0) or erosive (0.05 M citric acid solution at pH 2.3). Samples from each challenge were further categorized into 11 groups (n = 9) according to the duration of cariogenic (3, 7, and 14 days) or erosive (3, 7, and 10 days) challenge, along with positive control groups (fragments untreated with challenges and treated with different Biosilicate concentrations) and negative controls (fragments treated with artificial saliva for the same periods established for cariogenic and erosive challenges). Treatments with orodispersible films containing Biosilicate (30 and 50 mg) were administered for 2 min per day for 15 days. The highest remineralizing potential was observed in samples treated with Biosilicate after 14 days of cariogenic challenge, irrespective of the concentration tested. For samples subjected to erosive challenge, erosion time did not affect Biosilicate's remineralizing potential. Biosilicate shows promise in terms of remineralizing potential in enamel subjected to cariogenic challenge due to its ability to form hydroxycarbonapatite in mineralized tissues.

Examining enamel-surface demineralization upon exposure to acidic solutions and the remineralization potential of milk and artificial saliva.

The enamel surface may undergo demineralization due to exposure to acidic substances and the remineralization of the etched enamel is crucial to regain or maintain integrity. This study aimed to investigate the erosive effect of 10 acidic solutions on tooth enamel and the remineralization capacity of milk and artificial saliva by measuring surface roughness (Ra), enamel depth, and microhardness. A total of 80 bovine incisor enamel specimens were immersed in 10 different acidic solutions, including four different acidic drinks, three different citric acid solutions, and three different citric acid buffer solutions, for 1h. After demineralization, the specimens were immersed in milk and artificial saliva for 3h. Surface roughness, enamel abraded depth, and microhardness were measured before demineralization, in-between time intervals and after remineralization. Data were analyzed using Friedman and Kruskal-Wallis tests (p < 0.05). The results indicate a significant difference in surface roughness between the measurements taken at different time intervals, particularly between the baseline and after 1h demineralization. Also, the specimens immersed in CAB1 exhibited greatest increase in Ra among other acidic solutions (Δ: 0.18 ± 0.07). Moreover, only the microhardness increased after remineralization (p < 0.05). Enamel demineralization using various acidic solutions revealed increased Ra and enamel abraded depth, and decreased microhardness. The use of remineralization agents, milk and artificial saliva, demonstrated an increase in microhardness. This study provides insights into the effects of different acidic solutions and potential remineralization agents on tooth enamel.