Enamel Hardness Research Articles

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.

Evaluating the protective effects of mouthguards with neutralizing agents against chlorinated water-induced enamel erosion.

Dental erosion is a common problem among swimmers. This study evaluated the effects of mouthguard use with or without neutralizing agents, compared to no mouthguard use, on the microhardness of dental enamel after a swimming simulation. Ninety-six human premolars were randomly allocated into six groups of 16 each: Group A (no mouthguard), Group B (mouthguard only), Group C (mouthguard with fluoride toothpaste), Group D (mouthguard with fluoride-free toothpaste), Group E (mouthguard with CPP-ACP), and Group F (mouthguard with arginine-fluoride toothpaste). Enamel slabs were fixed in a wax model (Typodont Articulator) and used to fabricate mouthguards for all groups except Group A. Each specimen underwent cyclic immersion: 2 h in acidic chlorinated water (pH 3.1) followed by 22 h in artificial saliva, for 28 days, to simulate swimming exposure. The change in enamel surface hardness was measured using a Vickers hardness tester. All groups underwent microhardness testing, scanning electron microscopy, and polarized light microscopy. The enamel hardness significantly decreased in all groups after the swimming simulation (paired t-test, P-values < 0.001), except for Group F, which used a mouthguard with arginine-fluoride toothpaste [mean reduction: 17.9 kg/mm2, 95% confidence interval (CI): -1.9, 37.7, P-value = 0.07]. Group A, without a mouthguard, exhibited the highest reduction in enamel surface hardness (mean: 190.6 kg/mm2; 95%CI: 177.4, 203.9), significantly differing from all other groups with mouthguards (P-values < 0.001). However, no statistically significant differences were observed in enamel hardness reduction among the mouthguard groups. SEM micrographs illustrated rough, irregular erosion patterns and several deep porous areas on enamel surfaces of Group A. In contrast, all mouthguard groups showed enamel surfaces similar to sound tooth surfaces. A polarized light microscopic study revealed the deepest dark areas on the enamel surface of Group A. Mouthguards significantly reduced enamel microhardness loss compared to no mouthguard use. While no significant differences were found among mouthguard groups with or without neutralizing agents, those lined with arginine-fluoride toothpaste showed the least enamel loss, suggesting its potential protective effect. Within the limitations of this in vitro study, further clinical trials are needed to validate these results.

S. mutans Antisense vicK RNA Over-Expression Plus Antibacterial Dimethylaminohexadecyl Methacrylate Suppresses Oral Biofilms and Protects Enamel Hardness in Extracted Human Teeth.

Streptococcus mutans (S. mutans) antisense vicK RNA (ASvicK) is a non-coding RNA that regulates cariogenic virulence and metabolic activity. Dimethylaminohexadecyl methacrylate (DMAHDM), a quaternary ammonium methacrylate used in dental materials, has strong antibacterial activity. This study examined the effects of S. mutans ASvicK on DMAHDM susceptibility and their combined impact on inhibiting S. mutans biofilm formation and protecting enamel hardness. The parent S. mutans UA159 and ASvicK overexpressing S. mutans (ASvicK) were tested. The minimum inhibitory concentration (MIC) and minimum bactericidal concentrations for planktonic bacteria (MBC-P) and biofilms (MBC-B) were measured. As the ASvicK MBC-B was 175 μg/mL, live/dead staining, metabolic activity (MTT), colony-forming units (CFUs), biofilm biomass, polysaccharide, and lactic acid production were investigated at 175 μg/mL and 87.5 μg/mL. The MIC, MBC-P, and MBC-B values for DMAHDM for the ASvicK strain were half those of the UA159 strain. In addition, combining S. mutans ASvicK with DMAHDM resulted in a significant 4-log CFU reduction (p < 0.05), with notable decreases in polysaccharide levels and lactic acid production. In the in vitro cariogenic model, the combination achieved the highest enamel hardness at 67.1% of sound enamel, while UA159 without DMAHDM had the lowest at 16.4% (p < 0.05). Thus, S. mutans ASvicK enhanced DMAHDM susceptibility, and their combination effectively inhibited biofilm formation and minimized enamel demineralization. The S. mutans ASvicK + DMAHDM combination shows great potential for anti-caries dental applications.

In vitro assessment of NaF/Chit supramolecular complex: Colloidal stability, antibacterial activity and enamel protection against S. mutans biofilm

ObjectivesThis study assessed the effect of NaF/Chit suspensions on enamel and on S. mutans biofilm, simulating application of a mouthrinse. MethodsThe NaF/Chit particle suspensions were prepared at molar ratio [NaF]/Chitmon]≈0.68 at nominal concentrations of 0.2 % and 0.05 % NaF and characterized by Fourier transform infrared spectroscopy (FTIR), dynamic light scattering and zeta potential. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were measured. The S. mutans biofilm was formed for 7 days on eighty human enamel blocks that were divided into eight groups (n = 10/group): i) 0.05 % NaF solution; ii) 0.31 % Chit solution; iii) NaF/Chit(R=0.68) suspension at 0.05 % NaF; iv) 1.0 % HAc solution (Control); v) 0.2 % NaF solution; vi) 1.25 % Chit solution; vii) NaF/Chit(R=0.68) suspension at 0.2 % NaF; viii) 0.12 % chlorhexidine digluconate. The substances were applied daily for 90 s. S. mutans cell counts (CFU/mL) were performed, and the Knoop microhardness (KHN) of enamel samples were measured before and after biofilm formation. The KHN and CFU/mL data were analyzed by repeated measure ANOVA and Tukey's test (α = 0.05). ResultsInteractions between NaF and Chit were evidenced in solid state by FTIR spectra. The NaF/Chit complexes showed spontaneous microparticle formation and colloidal stability. The MIC and MBC ranged from 0.65 to 1.31 mg/mL. The NaF/Chit(R=0.68) suspension at 0.2 %NaF Group showed lower CFU/mL values than other groups. The NaF/Chit(R=0.68) suspensions Groups had the highest KHN values after biofilm formation. ConclusionsThe NaF/Chit(R=0.68) complexes exhibited an antibacterial effect against S. mutans biofilm and reduced the enamel hardness loss. Clinical significanceThe NaF/Chit(R=0.68) suspensions showed potential to be used as a mouthrinse for caries prevention.

The effects of beverage erosion on enamel: evaluating surface characteristics and loss of calcium and phosphate ions

BackgroundThe erosive impacts of various beverages on dental enamel have been identified as a potential erosive threat to dental hard tissues. This in vitro study aimed to address this by utilizing a systematic approach and advanced analytical methods to study enamel erosion due to selected beverages in a simulated oral environment.MethodsForty-nine extracted sound second premolar teeth were collected, disinfected, and prepared. These teeth were randomly allocated into seven groups, each exposed to a different beverage: distilled water, mineral water, instant coffee, black tea, Pepsi-Cola, orange juice, and synthetic vinegar. The modified Nordini Artificial Model (mNAM) was used to simulate the oral cavity. The enamel surfaces were scanned using a Scanning Electron Microscope (SEM) and analyzed using Energy-Dispersive X-ray Spectroscopy (EDS). Surface hardness was measured using the Knoop Hardness Scale. Statistical analysis was conducted using the Wilcoxon signed-rank test, with a significance level set at p < 0.05.ResultsDistilled water and mineral water exhibited no significant changes in enamel surface or hardness. Coffee caused an 8–9% loss of calcium and phosphate, indicating potential erosion. Black tea showed signs of remineralization rather than demineralization. Pepsi-Cola and orange juice caused substantial erosion, with Pepsi-Cola resulting in a nearly 24% loss of calcium. Vinegar had a marked erosive effect, with a 17% loss of both calcium and phosphate. SEM images corroborated these findings, showing pronounced enamel prisms and increased visibility of minor cracks in post-treatment teeth. EDS analysis revealed significant changes in the elemental composition of the enamel.ConclusionsThis study categorised beverages based on their pH and fluoride content, revealing that drinks like Pepsi-Cola and orange juice are acidic but low in fluoride, whereas black tea, mineral water, and vinegar are acidic yet contain fluoride. The study suggests that the decrease in pH of acidic beverages may contribute to dental erosion, with fluoride as a mitigating factor. Among the various metrics assessed for evaluating dental erosion, hardness emerged as the most reliable quantitative parameter.

Microhardness and characterization of human dental tissue after application of enzymatic chemical agents: In vitro study.

The use of enzymatic chemical agents are papain-based materials used in the selective removal of decayed dentin tissue, assisting in conservative techniques and reducing the chances of accidental pulp exposure. A research protocol was subjected to and approved by an Ethics Committee. Using a reporting guide for laboratory studies (CRIS). Healthy human teeth comprised the produced dentin discs subjected to polishing and washing in an ultrasonic bath. Next, the discs received material application according to the experimental groups: water-soluble gel for two minutes, 37% phosphoric acid for 15 seconds in dentin and 30 seconds in enamel, Papacárie Duo (PD) for 30 seconds and two minutes, and Brix 3000 (BX) for two minutes and 30 seconds. The measurement of material pH used solutions at concentrations of 0.1 ml and 2.7 ml prepared for each enzymatic agent. Then, a bench pH meter (n=10) and pH indicator strips determined pH values. The discs underwent the Knoop hardness test (n=10). The sample calculation was performed using the GPower software with α = 0.05, effect 0.63 and power of 95%. Descriptive statistical analysis was carried out for pH, one way ANOVA supplemented by Tukey for knoop hardness and Spearman correlation for pH measurement techniques. The enamel hardness findings indicated that, after material application, ECAs do not statistically differ from water-soluble gel (p<0.05). The dentinal hardness analysis presented a statistical difference in phosphoric acid from the other groups (p<0.05). In the pH test, BX values were lower (4.37 ± 0.01) than PD (4.85 ± 0.06). The groups statistically differed (p<0.05). ECAs for removing decayed dentin tissue did not significantly alter the hardness of enamel and dentin, removal of the smear layer is time-dependent and presents acidity. Key words:Dental caries, Hardness, Dental materials, Papain.

Posteruptive Loss of Enamel Proteins Concurs with Gain in Enamel Hardness.

Tooth enamel maturation requires the removal of proteins from the mineralizing enamel matrix to allow for crystallite growth until full hardness is reached to meet the mechanical needs of mastication. While this process takes up to several years in humans before the tooth erupts, it is greatly accelerated in in the faster developing pig. As a result, pig teeth erupt with softer, protein-rich enamel that is similar to hypomineralized human enamel but continues to harden quickly after eruption.Proteins, such as albumin, that bind to enamel crystals and prevent crystal growth and enamel hardening have been suggested as cause for hypomineralized human enamel that does not naturally harden after eruption. However, albumin is abundant in pig enamel. It is unclear whether fast posteruptive enamel hardening in pigs occurs despite the high protein content or requires a facilitated protein loss to allow for crystal growth. This study asked how the protein content in porcine enamel changes after eruption in relation to saliva. Based on previous data demonstrating the high albumin content in erupted porcine enamel, we hypothesize that following pre-eruptive maturation, enamel and saliva derived enzymes facilitate protein removal from porcine enamel after eruption. We analyzed enamel and the saliva proteome at three critical timepoints: at the time of tooth eruption, 2 weeks after eruption, and enamel 6 weeks after eruption. We used only fourth deciduous premolars and saliva samples from animals sacrificed at the respective time points to determine the organic content in tooth enamel, saliva, and saliva proteins within enamel. We found a decrease in the number of proteins and their abundancy in enamel with posteruptive time, including a decrease in serum albumin within enamel. The rapid decrease in the first two weeks is in line with previously reported rapid increase in mineral density of porcine enamel after eruption. In addition to the enamel proteases KLK-4 and MMP-20, we identified serine-, cysteine-, aspartic-, and metalloproteases. Some of these were only identified in enamel, while almost half of the enzymes are in common with saliva at all timepoints. Our findings suggest that the fast posteruptive enamel maturation in the porcine model coincides with saliva exchange and influx of saliva enzymes into porous enamel.

Influence of bottled salad dressings on the development of enamel erosion in the presence or absence of salivary pellicle – An in vitro study

BackgroundAcidic beverages are believed to elevate the risk of enamel surface erosion. In addition to the intake of soft drinks, the increased consumption of salad dressings has been linked to a higher prevalence of dental erosion. Therefore, the current study aimed to investigate the influence of bottled salad dressings on the development of enamel erosion in the presence or absence of pellicle through in vitro experiment. MethodsPreliminary pH and calcium analyses of solutions were performed. Highest pH and calcium content was found for sandwich spread i.e., 4.69 and 55.4 mg/100 g grams, respectively. Eighty tooth specimens (measuring 4 × 4 × 3 mm) were prepared from extracted human premolars and randomly assigned to four groups (group 1: orange juice; group 2: eggless plain mayonnaise; group 3: sandwich spread; and group 4: thousand island dressing) with 20 samples in each group. Ten tooth specimens from each group were immersed in 20 ml of the respective solutions for 5 min (control group). The remaining ten tooth specimens from each group were submerged in 5 mL saliva vials for 3 min to facilitate salivary pellicle formation before being immersed in their respective solutions for 5 min (saliva-covered group). Pre and post-experimental assessments of enamel roughness and hardness were conducted using a surface roughness tester and Knoop Hardness indenter, respectively. ResultsOverall, enamel roughness was notably elevated in the control group, with the eggless plain mayonnaise (0.52 ± 0.38) and thousand island dressing groups (0.57 ± 0.29) showing a significant increase in surface roughness post-test (p = 0.05). Nevertheless, there was no significant difference in the enamel roughness between the groups. On the other hand, regardless of the presence/absence of the salivary pellicle, a marked decrease in enamel hardness was observed among all groups except for group 3 (sandwich spread) with a mean score of 311.5 ± 82.6 (p < 0.05). ConclusionA significant increase in surface roughness and reduction in enamel hardness was observed with salad dressings. However, in vitro formed salivary pellicle showed a protective effect against tooth erosion.

ENAM Mutations Can Cause Hypomaturation Amelogenesis Imperfecta

Amelogenesis imperfecta (AI) is a diverse group of inherited diseases featured by various presentations of enamel malformations that are caused by disturbances at different stages of enamel formation. While hypoplastic AI suggests a thickness defect of enamel resulting from aberrations during the secretory stage of amelogenesis, hypomaturation AI indicates a deficiency of enamel mineralization and hardness established at the maturation stage. Mutations in ENAM, which encodes the largest enamel matrix protein, enamelin, have been demonstrated to cause generalized or local hypoplastic AI. Here, we characterized 2 AI families with disparate hypoplastic and hypomaturation enamel defects and identified 2 distinct indel mutations at the same location of ENAM, c588+1del and c.588+1dup. Minigene splicing assays demonstrated that they caused frameshifts and truncation of ENAM proteins, p.Asn197Ilefs*81 and p.Asn197Glufs*25, respectively. In situ hybridization of Enam on mouse mandibular incisors confirmed its restricted expression in secretory stage ameloblasts and suggested an indirect pathogenic mechanism underlying hypomaturation AI. In silico analyses indicated that these 2 truncated ENAMs might form amyloid structures and cause protein aggregation with themselves and with wild-type protein through the added aberrant region at their C-termini. Consistently, protein secretion assays demonstrated that the truncated proteins cannot be properly secreted and impede secretion of wild-type ENAM. Moreover, compared to the wild-type, overexpression of the mutant proteins significantly increased endoplasmic reticulum stress and upregulated the expression of unfolded protein response (UPR)–related genes and TNFRSF10B, a UPR-controlled proapoptotic gene. Caspase, terminal deoxynucleotidyl transferase UTP nick-end labeling (TUNEL), and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assays further revealed that both truncated proteins, especially p.Asn197Ilefs*81, induced cell apoptosis and decreased cell survival, suggesting that the 2 ENAM mutations cause AI through ameloblast cell pathology and death rather than through a simple loss of function. This study demonstrates that an ENAM mutation can lead to generalized hypomaturation enamel defects and suggests proteinopathy as a potential pathogenesis for ENAM-associated AI.

EFFECT OF 4 wt% HYDROXYAPATITE PASTA ON DENTAL EMAIL HARDNESS

Introduction: Dental erosion can affect the dental demineralization due to the pH level that is below the critical pH of 5,5 resulting a decrease in dental enamel hardness. Remineralization is needed to bring back the mineral loss. Hydroxyapatite is similar to inorganic components in dental enamel dan have biocompatible properties. Hydroxyapatite with 4 wt% concentration has a Ca/P molar ratio close to 1,67, which is similar to the human enamel and can regenerate enamel. This study is aimed to analyze the effects of 4 wt% hydroxyapatite paste on dental enamel hardness for 7 and 14 days. Material and Methods: 20 maxillary premolars were divided into 4 groups. Group A1 were applied with 4 wt% hydroxyapatite paste for 30 minutes each day for 7 days, group A2 were applied with 4 wt% hydroxyapatite paste for 30 minutes each day for 14 days, group B1 were immersed with artificial saliva for 7 days, and group B2 were immersed with artificial saliva for 14 days. All groups were immersed with artificial saliva and was incubated for 24 hours at 37°C. Hardness measurements were carried out at the start, after erosion, and at the end of the experiment. Dental enamel hardness was measured with Vickers Hardness Tester (Shimadzu HMV G-21 Series). Dental enamel hardness data were analysed with GLM Repeated Measure ANOVA test (p&lt;0,05) and One-way ANOVA test (p&lt;0,05). Results and Discussions: The result showed dental enamel hardness number after 4 wt% hydroxyapatite paste application showed significant difference than untreated group, which was immersed in artificial saliva. Dental enamel hardness number after 4 wt% hydroxyapatite paste application for 14 days showed significant difference than 7 days. Conclusion: It can be concluded that 4 wt% hydroxyapatite paste application for 14 days resulted in an increase of dental enamel hardness as in normal condition of dental enamel before erosion

An experimental teeth bleaching agent containing casein phosphopeptide-amorphous calcium phosphate.

This study was aimed to obtain an experimental bleaching agent by adding casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) in order to eliminate the mineral loss on the tooth surface after bleaching and to evaluate the bleaching effectiveness. In this study, experimental bleaching agents containing 1%, 3% CPP-ACP and without CPP-ACP were obtained. Bleaching effectiveness (color change), the effect of bleaching agents on mineral content (energy dispersive x-ray spectroscopy), surface morphology (scanning electron microscope), and surface hardness of enamel (Vicker's microhardness) before and after bleaching were evaluated. The obtained data were statistically analyzed. When the bleaching levels of the groups were compared, no statistically significant difference was observed between the control and 1% CPP-ACP groups (p > 0.05) while the addition of 3% CPP-ACP decreased significantly the effectiveness of the bleaching agent (p < 0.05). When the effects of experimental bleaching agents on surface hardness were examined, while the enamel surface hardness decreased statistically significantly after application in the control group (p < 0.05), no statistically significant change was observed in surface hardness after the application of 1% CPP-ACP containing bleaching agent (p > 0.05). However, a statistically significant increase was observed in surface hardness after the application of 3% CPP-ACP containing bleaching agent (p < 0.05). When the Ca and P ratio of the groups were compared, no statistically significant difference was observed between the control and 1% CPP-ACP groups (p > 0.05), while they increased significantly in 3% CPP-ACP group (p < 0.05). The addition of 1% CPP-ACP to the bleaching agent had positive effects on the mineral content and surface hardness of the enamel, and did not negatively affect the whitening effectiveness. Adding CPP-ACP to the bleaching agent at appropriate concentrations can eliminate possible negative effects without compromising the effectiveness of the bleaching agent.

PENGARUH PERENDAMAN AIR PDAM TERHADAP KEKERASAN ENAMEL GIGI PASKA HOME BLEACHING KARBAMID PEROKSIDA 20%

Background: One of the treatments to overcome the problem of discolored teeth is to do tooth whitening or bleaching. The tooth whitening agent that is often used is carbamide peroxide which is applied directly to the tooth enamel surface. Several factors that can affect tooth enamel are the degree of acidity or potential hydrogen (pH), acid concentration, dissolving time and the presence of calcium-like ions. Communities in Banjarmasin City still frequently use PDAM water for consumption and for their daily needs. Objective: To analyze the effect of immersing PDAM water and distilled water on the hardness of tooth enamel after the application of 20% carbamide peroxide. Methods: This study used a true experimental method with a posttest-only with control group design consisting of 4 treatment groups namely positive control PDAM water, negative control Aquatic water, group 1 carbamide peroxide 20% and PDAM water, and group 2 carbamide peroxide 20% and distilled water. Tooth enamel hardness was measured using a Vickers microhardness tester. Results: analysis of the One Way Anova test with Post-Hoc Bonferroni showed that there was a significant difference in violence in each group (p&gt;0.05). Conclusion: There is an effect of PDAM water after application of 20% carbamide peroxide on the hardness of enamel on teeth.Keywords: Carbamide Peroxide 20%, Discolored, Enamel Hardness, PDAM

Effects of Dental Bleaching Treatment Ingredients and Their Influence on the Hardness of Tooth Enamel

Dental bleaching treatment is currently a trend at the moment. Dental bleaching treatment is not only for aesthetics but a person can become more confident with white teeth. However, it turns out that it has bad effects if it does not comply with correct dental principles, especially in selecting dental bleaching materials. Know the ingredients, effects and methods for whitening teeth, including those that can be used by patients themselves, with or without professional supervision, and products for professional use. This literature study uses the Narrative Review method. References were collected in the form of journals through databases and online websites of BMC Oral Health, PubMed, Wacana and Google Scholar. References are also selected through reference analysis in the form of research, articles and systematic reviews. Carbamide Peroxide can be recommended as a choice of dental bleaching agent because it has a remineralization effect and increases the microhardness of enamel after 8 weeks of application.

Effectiveness of Etawa goat milk casein paste on increasing permanent tooth enamel hardness

Demineralization is the process of mineral solubility that affects the hardness of tooth enamel. Etawa goat milk casein contains bioactive peptides that can enhance the hardness of tooth enamel through remineralization, which is the restoration of dissolved minerals. This study aims to determine the effectiveness of etawa goat milk casein paste on increasing permanent tooth enamel hardness. The method employed in this research involved applying etawa goat milk casein paste with concentrations of 10%, 20%, and 30% respectively to the buccal surface of the first permanent upper premolar teeth that had been demineralized. Subsequently, the teeth were immersed in artificial saliva and placed in an incubator at 37°C for a 24-hour interval. The treatment was conducted over a period of 14 days. Pretest and post-test enamel hardness measurements were performed using a digital Microhardness Vickers Test. There was an increase in the hardness value of permanent tooth enamel following the application of etawa goat milk casein paste. One Way ANOVA and Pearson correlation tests indicated significant results. Etawa goat milk casein paste is effective in increasing permanent tooth enamel hardness.

Changes in enamel hardness, wear resistance, surface texture, and surface crystal structure with glass ionomer cement containing BioUnion fillers.

This study investigated the potential of BioUnion filler containing glass ionomer cement (GIC) to enhance the properties of enamel surrounding restorations, with a specific focus on the effect on hardness. The hardness of the bovine enamel immersed in the cement was measured using Vickers hardness numbers. Following sliding and impact wear simulations, the enamel facets were examined using confocal-laser-scanning microscopy and scanning-electron microscopy. Surface properties were further analyzed using energy-dispersive X-ray spectroscopy and X-ray diffraction (XRD). A significant increase in Vickers hardness numbers was observed in the BioUnion filler GIC after 2 days. Furthermore, the mean depth of enamel facets treated with BioUnion filler GIC was significantly less than that of untreated facets. Characteristic XRD peaks indicating the presence of hydroxyapatite were also observed. Our findings imply that GIC with BioUnion fillers enhances the mechanical properties of the tooth surface adjacent to the cement.

Abstract 6035: Fluoride effects on thermal properties of irradiated dentin and enamel

Abstract Aim: Radiation therapy to treat oral cancer introduces various harms, including decreased hardness of dentin and enamel. Fluoride treatments, including silver diamine fluoride (SDF), have been used as a tool to combat these harms, but its influences on the thermal properties of dentin and enamel prior to and after radiation therapy are not well understood. Thus, this study analyzed how SDF influences the thermal stability of dentin and enamel that has been exposed to radiation therapy intended for head and neck cancer patients. Methods: Forty human posterior teeth were collected, cleaned of debris and soft tissue, and then mounted into acrylic resin molds. The teeth were divided into two equal groups, with one group being the control (no treatment) and the other group receiving SDF treatment. Using an X-Rad 320ix biological irradiator, all teeth were subjected to two grays of radiation therapy every day for six weeks. Afterwards, the dentin and enamel were pulverized a SPEX freezer mill. Samples were heated in a NETZSCH Thermal Analysis instrument, and the amount of carbon dioxide and water released was determined. All teeth were heated to 1429 °C from room temperature. Results: The SDF-treated dentin released the most carbon dioxide (49,611.82 ppm/mg), followed by irradiated dentin (47,672.76 ppm/mg) and untreated dentin (45,249.66 ppm/mg). In contrast, the SDF-treated enamel released less carbon dioxide (7,367.62 ppm/mg) than the control enamel (8,172.01 ppm/mg). The pattern of release of water was different from that of carbon dioxide. The control dentin group released the most water (45.56 ppt/mg), followed by the SDF-treated (39.72 ppt/mg) and irradiated dentin (23.51 ppt/mg). Similarly, the control enamel also released the highest amount of water (0.83 ppt/mg), as well as the highest amount of carbon dioxide. The SDF-treated enamel released around 65% of the water compared to the control enamel group (0.54 ppt/mg). Furthermore, the irradiated dentin had the largest heat reversal temperatures for carbon dioxide (85.19 °C) and water (86.57 °C). Conclusions: The impacts of SDF treatment and radiation vary between dentin and enamel. Comparatively, dentin has a higher content of combustible material than enamel. Radiation treatment reduces the water content of both enamel and dentin, which may make teeth more susceptible to fracture. Therefore, regular dental check-ups and frequent fluoride treatment to increase the strength of the teeth are recommended for patients undergoing radiation therapy. Citation Format: Rachel J. Kulchar, Yusuke Kakiuchi, Vania Sanchez-Gamarra, Jie Deng, Francis Mante. Fluoride effects on thermal properties of irradiated dentin and enamel [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6035.

Influence of coating dental enamel with a TiF4-loaded polymeric primer on the adverse effects caused by a bleaching gel with 35% H2O2

ObjectiveTo evaluate whether coating enamel with a polymeric primer (PPol) containing titanium tetrafluoride (TiF4) before applying a bleaching gel with 35% H2O2 (35% BG) increases esthetic efficacy, prevents changes in morphology and hardness of enamel, as well as reduces the cytotoxicity from conventional in-office bleaching. Materials and methodsStandardized enamel/dentin discs were stained and bleached for 45 min (one session) with 35% BG. Groups 2TiF4, 6TiF4, and 10TiF4 received the gel on the enamel previously coated with PPol containing 2 mg/mL, 6 mg/mL, or 10 mg/mL, respectively. No treatment or application of 35% BG directly on enamel were used as negative control (NC), and positive control (PC), respectively. UV-reflectance spectrophotometry (CIE L*a*b* system, ΔE00, and ΔWI, n = 8) determined the bleaching efficacy of treatments. Enamel microhardness (Knoop, n = 8), morphology, and composition (SEM/EDS, n = 4) were also evaluated. Enamel/dentin discs adapted to artificial pulp chambers (n = 8) were used for trans-amelodentinal cytotoxicity tests. Following the treatments, the extracts (culture medium + bleaching gel components diffused through the discs) were collected and applied to odontoblast-like MDPC-23 cells, which were assessed concerning their viability (alamarBlue, n = 8; Live/Dead, n = 4), oxidative stress (n = 8), and morphology (SEM). The amount of H2O2 in the extracts was also determined (leuco crystal violet/peroxidase, n = 8). The numerical data underwent one-criterion variance analysis (one-way ANOVA), followed by Tukey's test, at a 5% significance level. ResultsRegarding the ΔE00, no difference was observed among groups 2TiF4, 6TiF4, and PC (p > 0.05). The ΔWI was similar between groups 2TiF4 and PC (p > 0.05). The ΔWI of group 6TiF4 was superior to PC (p < 0.05), and group 10TiF4 achieved the highest ΔE00 and ΔWI values (p < 0.05). Besides limiting enamel microstructural changes compared to PC, group 10TiF4 significantly increased the hardness of this mineralized dental tissue. The highest cellular viability occurred in 10TiF4 compared to the other bleached groups (p < 0.05). Trans-amelodentinal H2O2 diffusion decreased in groups 2TiF4, 6TiF4, and 10TiF4 in comparison with PC (p < 0.05). ConclusionCoating enamel with a PPol containing TiF4 before applying a 35% BG may increase enamel microhardness and esthetic efficacy and reduce the trans-amelodentinal cytotoxicity of conventional in-office tooth bleaching. The PPol containing 10 mg/mL of TiF4 promoted the best outcomes.

Effect of saliva of patients with leukemia on surface hardness and roughness of enamel and dental composite resin during chemotherapy regimen: An – Invitro study

Background: Evaluate the surface roughness and hardness of tooth enamel and dental resin composite restoration immersed into saliva collected from leukemia patient. Objective: To evaluate the surface roughness and hardness of tooth enamel and dental resin composite restoration immersed on to saliva collected from 4 types of leukemia patient. Patients and Methods: 30 patients with 4 types of leukemia (Acute lymphoblastic leukemia ALL, Acute myeloid leukemia AML, Chronic lymphocytic leukemia CLL, and Chronic myeloid leukemia CML) were included for taking saliva separately. A total number of 50 enamel specimen and 50 of composite resin disk were prepared and randomly divided into 5 groups of enamel (1,2,3,4, and 5) and 5 groups of composite resin disk (A,B,C,D, and E), surface roughness and hardness were measured and data collected, group A and 1 were immersed in artificial saliva for 7 days as control, group B and 2 immersed into saliva collected from patient with ALL, group C and 3 immersed into saliva collected from patient with AML, group D and 4 immersed into saliva collected from patient with CLL and group E and 5 immersed into saliva collected from patient with CML all group for 7 days then surface roughness and hardness were measured data collected and analyzed and statistically significant regarded at p&lt;0.05. Results: In group A and 1 artificial saliva there were no significant effect on surface roughness and hardness of both enamel and composite resin disk, while surface roughness and hardness of enamel and composite resin significantly changed after immersing in saliva of ALL, AML, CLL, patients and surface roughness of composite resin highly significantly increased after immersing in saliva of CML patients. Conclusion: Saliva of ALL, AML, CLL, and CML seems to significantly changes in mechanical properties of enamel and composite, however saliva of CML highly significantly increase surface roughness of composite resin. Keywords: 4 types’ leukemia, chemotherapy, surface roughness and hardness, enamel, dental composite resin.

Effect of saliva of patients with leukemia on surface hardness and roughness of enamel and dental composite resin during chemotherapy regimen: An – Invitro study

Background: Evaluate the surface roughness and hardness of tooth enamel and dental resin composite restoration immersed into saliva collected from leukemia patient.&#x0D; Objective: To evaluate the surface roughness and hardness of tooth enamel and dental resin composite restoration immersed on to saliva collected from 4 types of leukemia patient.&#x0D; Patients and Methods: 30 patients with 4 types of leukemia (Acute lymphoblastic leukemia ALL, Acute myeloid leukemia AML, Chronic lymphocytic leukemia CLL, and Chronic myeloid leukemia CML) were included for taking saliva separately. A total number of 50 enamel specimen and 50 of composite resin disk were prepared and randomly divided into 5 groups of enamel (1,2,3,4, and 5) and 5 groups of composite resin disk (A,B,C,D, and E), surface roughness and hardness were measured and data collected, group A and 1 were immersed in artificial saliva for 7 days as control, group B and 2 immersed into saliva collected from patient with ALL, group C and 3 immersed into saliva collected from patient with AML, group D and 4 immersed into saliva collected from patient with CLL and group E and 5 immersed into saliva collected from patient with CML all group for 7 days then surface roughness and hardness were measured data collected and analyzed and statistically significant regarded at p&lt;0.05.&#x0D; Results: In group A and 1 artificial saliva there were no significant effect on surface roughness and hardness of both enamel and composite resin disk, while surface roughness and hardness of enamel and composite resin significantly changed after immersing in saliva of ALL, AML, CLL, patients and surface roughness of composite resin highly significantly increased after immersing in saliva of CML patients.&#x0D; Conclusion: Saliva of ALL, AML, CLL, and CML seems to significantly changes in mechanical properties of enamel and composite, however saliva of CML highly significantly increase surface roughness of composite resin.

Effect of lactoferrin on enamel characteristics of primary and permanent teeth: an in-vitro study

BackgroundLactoferrin, a glycoprotein naturally found in breast milk, is known for its bactericidal and antiviral properties, as well as its capacity to modulate the immune system; therefore, pediatricians routinely recommend it as dietary support. The objective of this study was to determine how lactoferrin oral suspension could affect the enamel surface characteristics of primary and permanent teeth.MethodsThis research was conducted on 40 unidentified extracted teeth, including primary and permanent teeth. Experimental teeth were free of cracks or enamel defects, as confirmed by careful examination using a dental operating microscope. The crowns were bisected into 80 specimens and assorted into two groups based on the type of dentition. Group DM included 40 specimens of second deciduous molars, while Group PM contained 40 samples of first premolars. Each of the DM and PM specimens was subsequently split based on the type of dispersion medium into two subgroups: a control subgroup (artificial saliva) and a test subgroup (lactoferrin suspension). The specimens were immersed in lactoferrin suspension for two minutes, then kept in artificial saliva for the rest of the 24 h for 30 successive days. This is a pioneering study about the effect of orally supplemented lactoferrin on teeth; therefore, we examined enamel hardness, ultra-morphology, and mineral contents.ResultsOur findings indicated a highly significant decrease (p < 0.01) in the microhardness of the lactoferrin subgroup in Group DM (second deciduous molars) and a significant reduction (p < 0.05) in the microhardness of the lactoferrin subgroup in Group PM (premolars). Calcium weight% was not statistically different (p > 0.05) compared with a significant decline (p < 0.05) in phosphorus weight% in lactoferrin subgroups in both DM and PM groups. The enamel surface of lactoferrin subgroups in both DM and PM groups was demineralized and porous, with the enamel of deciduous teeth being more affected by lactoferrin than permanent teeth.ConclusionLactoferrin suspension decreased the microhardness of enamel and both calcium and phosphorus weight percentages. Both dentitions exhibited erosions in the enamel surface, with primary teeth being more affected than the permanent teeth.