Effect of a demineralization model on the microhardness, surface roughness and topography of giomers: An in vitro study.

The purpose of this study is to compare the effect of a demineralization model on the microhardness, surface roughness, and topography of giomers.Seventy-two discs of six different dental materials in three different presentations (pit and fissure sealant (PFS), flowable and restorative materials) were divided into six groups (n = 12 p/g). Three experimental groups (giomers) consisted of BeautiSealant, Beautifil Flow Plus, and Beautifil II, and three control groups (resin-based materials) were formed using ClinproTM, FiltekTM Z350 XT Flow, and Filtek™ Bulk Fill materials. Vickers microhardness, surface roughness, and topographic analysis with atomic force microscopy were measured at the beginning (0) after four (1) and 7 days (2) of immersion in a demineralizing model. Statistical analysis was performed using One-way and Repeated Measures ANOVA and Pearson's correlation coefficient (p ≤ .05). The microhardness values showed significant variations, except for the G_RM group. All the groups presented significant increases in roughness through the experiment stages, except for RB_PFS in the Ra parameter. The topographic analysis showed variations in the micromorphology, especially in the experimental group at the end of the demineralization model. Finally, there was no correlation between microhardness and surface roughness. The demineralization model decreased the microhardness, with the lowest reductions in the giomers groups. The effect of the demineralizing model on the surface roughness and topography showed an increase in specific patterns for the experimental and control groups. Therefore, their clinical use is recommended. RESEARCH HIGHLIGHTS: The demineralization model decreased the microhardness property of the evaluated materials, with better performance for the giomer groups. The effect of the demineralizing model on surface roughness showed an increase with specific patterns for the experimental and control groups. Although the materials presented changes in their microhardness, roughness, and topography, their clinical use is recommended.

Effect of different industrialized acid beverages on the surface roughness of flowable composite resins: in vitro study.

Flowable composite resins are materials available for restorations in pediatric dentistry. However, these materials are subject to dangerous effects in the oral environment caused by acids that deteriorate and increase their roughness. Therefore it is important to evaluate the effect of different industrialized acid beverages on the roughness of flowable composite resins. An in vitro experimental study, was done using a convenience sample of 132 discs of 5 mm diameter by 2 mm depth of four flowable materials (FF (Filtek™ Z350 XT Flowable), TNF (Tetric® N-Flow), PF (PermaFlo®) and GF (Grandio® Flow)) exposed to three beverages (CC (Coca-Cola), AJ (apple juice), and FM (fermented milk)) and incubated at 37 ºC for 0, 15 and 30 days. The roughness (average roughness (Ra) and maximum height of profile (Rz) parameters) was measured at different intervals of time with a profilometer. For the data analysis, one-way analysis of variance (one-way ANOVA) and repeated measures analysis of variance (Repeated measures ANOVA) tests were applied (p < 0.05). In the roughness test before immersion, no differences were observed within the groups, with maximum roughness values for Filtek™ Z350 XT Flowable and minimum for PermaFlo®. However, at 15 and 30 days of immersion, the groups showed significant differences depending on the immersion drink, except Grandio® Flow in apple juice and fermented milk. The flowable materials studied presented specific behaviors according to the immersion period and drink used. The Filtek™ Z350 XT Flowable showed a similar increase in surface roughness independently of the drink used. Grandio® Flow was the most stable material against surface roughness changes after beverage immersion.

Effect of some industrialized acidic beverages on the roughness of pit and fissure sealants: an in vitro study.

This study evaluated in vitro the roughness of the pit and fissure sealants (PFS) after immersion in some industrialized acidic beverages. 120 discs (5 mm diameter and 2 mm thick) of 4 commercial brands (3M, Ivoclar, Ultradent, and VOCO) were immersed in 1.5 mL of 3 different industrialized acid beverages (soft drink, apple juice, and fermented milk) and incubated at 37 ºC for 15 and 30 days. Surface roughness (Ra and Rz) was measured at the beginning (0), 15 (1), and 30 days (2) after immersion, using a profilometer, under the standard ISO 4287-1997. Data were analyzed with one-way analysis of variance (One-way ANOVA) and repeated measures analysis of variance (Repeated measures ANOVA) test (p < 0.05). Ultradent and VOCO had the higher baseline surface roughness values, while 3M presented the lower baseline values (p > 0.05). After 15 and 30 days of immersion, the 3M group still showed the minimum values of surface roughness (p < 0.05). In addition, the maximum roughness values were seen in group UC (Ultradent/Coca-Cola) (p < 0.05). The surface roughness of the PFS increased according to the period of immersion in some industrialized acidic beverages. This increase was specific to each commercial brand. Therefore, the 3M PFS presented the best performance before and after immersion in the beverages.

Trends in Cleft lip and/or Palate Prevalence at Birth in Mexico: A National (Ecological) Study Between 2003 and 2019.

OBJECTIVE: To describe trends in cases and prevalence at birth rates of cleft lip and/or palate (CL/P) in Mexico between 2003 and 2019. DESIGN: Ecological study. SETTING: Multiple data sources systematically collected into a national epidemiological surveillance data warehouse. PARTICIPANTS: National Live Birth Information System. MAIN OUTCOME MEASURE(S): Both cases and prevalence at birth rates of CL/P in Mexico within a 17-year period were used as dependent variables. RESULTS: At the national level there were 23 184 new cases of CL/P (average of 1364 per year) in the 32 states of Mexico, with an average prevalence at birth rate of 0.53 per 1000 live births. The states with the highest prevalence at birth rates of CL/P during the period were Hidalgo (1.59) and Jalisco (1.32), while the states with the lowest rates were Nayarit (0.22) and Durango (0.29). A slight decrease in both cases (z = -2.41, P = .016) and prevalence at birth rates (z = -2.58, P = .010) of CL/P was observed at the national level. States such as Durango, Puebla, Chiapas, Guerrero, Oaxaca, Mexico City, State of Mexico, Coahuila and Jalisco showed a clear downward trend (P < .05) in their prevalence at birth of CL/P between 2003 and 2019, while in Hidalgo its trend was upward (P = .05). Significant differences by sex and region were observed (P < .05). CONCLUSION: Some states consistently had the highest or lowest prevalence of CL/P. Decreasing trends in the overall prevalence at birth rates were observed. More detailed, epidemiological studies are necessary to adequately characterize CL/P in the Mexican population.

Effect of Surface Roughness of Deciduous and Permanent Tooth Enamel on Bacterial Adhesion.

The adhesion of some bacteria has been attributed to critical levels of roughness in hard tissues, which increases the risk of developing caries. The objective of this work was to assess the effect of deciduous and permanent tooth enamel surface roughness on bacterial adhesion. One hundred and eight samples of deciduous and permanent enamel were divided into two groups (n = 54). G1_DE deciduous enamel and G2_PE permanent enamel. The surface roughness was measured by profilometry and atomic force microscopy (AFM). Subsequently, the evaluation of bacterial adherence was carried out in triplicate by means of the XTT cell viability test. Additionally, bacterial adhesion was observed using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). The average values of the micrometric roughness in both groups were similar; however, in the nanometric scale they presented significant differences. Additionally, the G1_DE group showed the highest amount of adhered S. mutans and S. sanguinis compared to the G2_EP group. Although the roughness of deciduous and permanent enamel showed contrasting results according to the evaluation technique (area and scale of analysis), bacterial adhesion was greater in deciduous enamel; hence, enamel roughness may not be a determining factor in the bacterial adhesion phenomenon.

Evaluation of tooth demineralization using laser-fluorescence in dental school patients undergoing orthodontic treatment: A clinical study.

BACKGROUND: Adverse effects can occur during orthodontic treatment. OBJECTIVE: To evaluate the relationship between prevalence and severity of enamel demineralization using a laser-fluorescence device, with length of orthodontic treatment time. METHOD: A cross-sectional study was conducted in 60 patients in a university orthodontic clinic. A clinical examination to establish demineralization at four sites on each tooth (premolar to premolar) was performed using the DIAGNOdent pen. The dependent variable was enamel demineralization, from which the prevalence (at least one affected site), extension (percentage of affected teeth) and adjusted average (average of the mean DIAGNOdent values per tooth) were calculated. The length of time for orthodontic treatment was determined in months. Various sociodemographic and clinical covariates were included. RESULTS: Average number of months under orthodontic treatment was 26.37 ± 24.81 months. Prevalence of enamel demineralization was 80.0%, its extension was 21.9% ± 17.2 and adjusted average of DIAGNOdent values was 6.09 ± 1.75. By quadrant, the teeth most affected were 14 (34.4%), 24 (25.0%), 31 (30.2%) and 44 (33.3%). No significant relationship (p> 0.05) was observed between enamel demineralization and length of time under orthodontic treatment. CONCLUSIONS: A high prevalence of dental demineralization was observed. In this sample, no relationship was observed between months under treatment and dental demineralization, or with other variables included in the study.

Morphological and porosity changes in primary enamel surface after an in vitro demineralization model.

In vitro models are very useful in dentistry, especially to evaluate preventive methods against dental caries. Although they have been used for more than 30 years, specific demineralization models have not been established for primary enamel, which is more prone to demineralization than permanent enamel. This study evaluates porosity changes in primary enamel surface after a demineralization model through a scientifically validated analytical tool. Nine healthy human anterior primary teeth extracted for therapeutic reasons were included in this study, previous informed consent. The samples were randomly assigned to three groups n = 3: G1_2D, G2_4D, and G3_7D. Scanning electron microscopy (SEM) images at ×200 and ×1000 were taken during two stages: before demineralization (BD) and after demineralization (AD). Morphological characterization was observed at ×1000, while porosity (pore count and perimeter) was analyzed by the ImageJ program, using ×200 SEM images previously converted. Several statistical analyses were used to determine differences (p ≤ .05). Morphological characterization AD revealed new pits and cracks on the enamel surface in G1_2D and G2_4D groups. Localized eroded enamel areas were observed in G3_7D. Pore count of enamel surface BD ranged from 64.26 ± 37.62 to 97.93 ± 34.25 and AD ranged from 150.06 ± 64.86 to 256 ± 58.14. AD, G_4D exhibited a decrease in pore perimeter contrary to G_2D and G_7D. Significant differences were observed. Finally, morphological changes were more evident as days of demineralization increased; 7 days of immersion could be employed as an enamel erosive model. The pore count increased after the demineralization model, BD pores perimeter was heterogeneous, and AD varied according to the immersion period. Morphological changes were more evident as days of demineralization increased. Seven days of immersion could be employed as an enamel erosive model. The initial porosity seems to be a determining factor for the final porousness. The pore perimeter of the primary enamel varied according to the immersion period on the demineralization model.

The influence of light-curing time on fluoride release, surface topography, and bacterial adhesion in resin-modified glass ionomer cements: AFM and SEM in vitro study.

Reinforced glass ionomer cements have been widely used in pediatric dentistry to prevent dental caries. However, the influence of biomaterial light-curing and its anti-cariogenic effects remain unclear. This study evaluates the influence of the light-curing time on fluoride release, surface topography, and bacterial adhesion in two types of resin-modified glass ionomer cements (RMGICs). One hundred disks were made, and samples were divided into two groups (n = 50 per group), according to each dental material (Vitremer™ and Ketac™ N100), and also divided into different light-cured times (10, 20, 30, 40, and 60 s). They were placed in phosphate-buffered saline solution (PBS) to measure the fluoride release. Subsequently, an independent sample of RMGICs per group was examined using atomic force microscopy (AFM). Four disks per group were incubated in a brain heart infusion (BHI) medium that was inoculated with Streptococcus mutans GS5 to evaluate the bacterial adhesion by 3-4, [5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide cell viability assay (MTT assay). The fluoride release was related to the light-curing time and gradually decreased as the light-curing time increased in both materials. Surface topography in Vitremer™ presents more irregular surfaces than Ketac™ N100. For S. mutans adhesion, the smallest number of cells per milliliter (cell/ml) was found at 40 s for Vitremer™ and at 30 s for Ketac™ N100. Thus, the shorter light-curing times allowed for major fluoride release in both materials. However, the RMGICs showed different patterns of bacterial adhesion according to the brand and light-curing time.

Enamel demineralization model in primary teeth: Micro-CT and SEM assessments of artificial incipient lesion.

Many studies have analyzed different tooth demineralization models, which generate artificial incipient lesions; however, most of them are complex, slow, not clear and results could not be employed in both primary and permanent teeth because of chemical content differences among them. This study evaluates a demineralization model on primary enamel, under three incubation periods; quantifying artificial incipient lesions formation, and depth by micro-CT, complementing with SEM for morphological characterization. Sixteen healthy human anterior primary teeth extracted for prolonged retention and orthopedic/orthodontic reasons were included in this study, previous informed consent. The sample was randomly assigned to four groups n = 4: G_Control, G_2D, G_4D, and G_7D. Micro-CT and SEM were performed during two stages: before demineralization (BD) and after demineralization (AD). A t-student test was carried out to determine differences among groups (p ≤ .05). No incipient lesions were observed in control group. Artificial lesion depth was similar among experimental groups; values were from 38.16 ± 05.40 µm to 42.61 ± 04.75 µm. An amount of 14 to 17 artificial incipient lesions were formed per group, the extension and distribution were different for each incubation period. Five erosive lesions were produced in G_7D. All experimental groups were able to form incipient artificial lesions in primary enamel. SEM characterization revealed more pronounced changes on the enamel surface, as the days of immersion in the demineralization solution increased. The 4-day incubation period is the most recommended for the demineralization model, due to the formation of incipient lesions only and its extension, which facilitates their assessment.

Effect of Er:YAG laser irradiation on deciduous enamel roughness and bacterial adhesion: An in vitro study.

Laser irradiation has been proposed as a preventive method against dental caries since it is capable to inhibit enamel demineralization by reducing carbonate and modifying organic matter, yet it can produce significant morphological changes. The purpose of this study was to evaluate the influence of Er:YAG laser irradiation on superficial roughness of deciduous dental enamel and bacterial adhesion. Fifty-four samples of deciduous enamel were divided into three groups (n = 18 each). G1_control (nonirradiated); G2_100 (7.5 J/cm2 ) and G3_100 (12.7 J/cm2 ) were irradiated with Er:YAG laser at 7.5 and 12.7 J/cm2 , respectively, under water irrigation. Surface roughness was measured before and after irradiation using a profilometer. Afterwards, six samples per group were used to measure bacterial growth by XTT cell viability assay. Adhered bacteria were observed using confocal laser scanning microscopy (CLSM) and a scanning electron microscopy (SEM). Paired t-, one-way analysis of variance (ANOVA), Kruskal-Wallis and pairwise Mann-Whitney U tests were performed to analyze statistical differences (p < .05). Before treatment, samples showed homogenous surface roughness, and after Er:YAG laser irradiation, the surfaces showed a significant increase in roughness values (p < .05). G3_100 (12.7 J/cm2 ) showed the highest amount of Streptococcus mutans adhered (p < .05). The increase in the roughness of the tooth enamel surfaces was proportional to the energy density used; the increase in surface roughness caused by laser irradiation did not augment the adhesion of Streptococcus sanguinis; only the use of the energy density of 12.7 J/cm2 favored significantly the adhesion of S. mutans.

Effect of Er:YAG and Fluoride Varnishes for Preventing Primary Enamel Demineralisation.

PURPOSE: To measure the demineralisation changes on human deciduous enamel produced by pH cycling after preventive treatment with Er:YAG laser irradiation, fluoride varnish application and a combination of the two. MATERIALS AND METHODS: Sixty extracted human anterior primary teeth were assigned to six groups (n = 10). Group C: untreated; group L: Er:YAG laser; group TCP-NaF: Clinpro White (5% sodium fluoride and modified tricalcium phosphate); group CPP-ACP-NaF: MI varnish (5% sodium fluoride with casein phosphopeptide-amorphous and calcium phosphate); group L+TCP-NaF: Er:YAG + 5% sodium fluoride + modified tricalcium phosphate; group L+ CPP-ACP-NaF: Er:YAG + 5% sodium fluoride with casein phosphopeptide-amorphous and calcium phosphate. The samples were subjected to a 10-day pH-cycling regimen to create caries-like lesions, with 8 h in demineralising solution and 16 h in remineralising solution at 37°C. Enamel demineralisation was evaluated by laser fluorescence (DIAGNOdent) before and after pH cycling. The Mann-Whitney U-test and Wilcoxon tests were performed with statistical significance set at p ≤ 0.05. RESULTS: The Wilcoxon test revealed statistically significant differences at baseline and after pH cycling in groups C (p = 0.02), L (p = 0.034) and L+TCP-NaF (p = 0.025) and the lowest percentage of healthy tooth substance compared to the other groups. CONCLUSIONS: The results suggest that the treatment protocols employed in groups TCP-NaF, CPP-ACP-NaF, and L+ CPP-ACP-NaF had similar effects in terms of preventing demineralisation, as reflected in a higher percentage of healthy dental structure maintained. Hence, these treatments are recommended for clinical use as an effective preventive measure.

Acid resistance of dental enamel treated with remineralizing agents, Er:YAG laser and combined treatments.

BACKGROUND: It has been reported that lasers can increase resistance to enamel acids, and when it is associated with fluoride, both are reported to work in synergy, achieving a reduction of the solubility of enamel. Currently, other remineralizing agents have been shown to effectively inhibit enamel demineralization. OBJECTIVES: The aim of the study was to evaluate acid resistance in the occlusal surface of permanent teeth, treated with remineralizing agents, erbium-doped yttrium aluminum garnet (Er:YAG) laser and combined treatments. MATERIAL AND METHODS: Eighty samples of enamel were randomly assigned to 8 groups (n = 10): a control group, and groups treated with sodium fluoride (NaF), casein phosphopeptide-amorphous calcium phosphate with NaF (CPP-ACPF), hydroxyapatite-NaF-xylitol (HA-NaF-X), Er:YAG laser (L), L+NaF, L+CPP-ACPF, and L+HA-NaF-X. The samples were placed in an acid solution and the released calcium (Ca) was quantified by atomic absorption spectrometry. RESULTS: In the groups treated with NaF and L+NaF, a lower loss of Ca was observed - 15.27 ±5.17 mg/L and 15.20 ±3.85 mg/L, respectively - compared to the control group, which had the highest Ca loss: 21.93 ±13.24 mg/L. CONCLUSIONS: Although the combination of Er:YAG laser plus NaF and the single application of NaF showed values suggesting superior resistance to demineralization of dental enamel compared to all the other groups in the study, no statistically significant differences were found to support this assertion.

Adhesion of Streptococcus mutans and Streptococcus sanguinis on Er:YAG Laser-Irradiated Dental Enamel: Effect of Surface Roughness.

Objective: To determine surface roughness caused by Er:YAG laser irradiation and its effect on the increase in bacterial adhesion. Background: Er:YAG laser was proposed as a strategic device to reduce caries by its ability to generate chemical and structural changes in tooth enamel; in turn, it produces undesirable effects on the tooth surface that could increase its roughness and allow a greater accumulation of microorganisms. Methods: Eighty-four samples of human enamel were divided into seven groups (n = 12): G1_control (no laser irradiation); G2_100/H2O, G3_200/H2O, and G4_300/H2O were irradiated with Er:YAG laser (12.7, 25.5, and 38.2 J/cm2, respectively) under water irrigation. In addition, G5_100, G6_200, and G7_300 were irradiated with the energy densities described above and no water irrigation. Surface roughness measurements were recorded before and after treatment using a profilometer. Afterward, three samples per group were incubated in a microorganism suspension for the tetrazolium salt (XTT) assay. Biofilm morphology was observed using scanning electron microscopy and confocal laser scanning microscope. One-way analysis of variance and t-tests were performed for statistical analysis (p < 0.05). Results: There were no statistically significant differences in roughness values in the G5_100 group before and after treatment, but there were statistically significant differences observed in the other groups evaluated (p < 0.05). No significant differences in adhesion of both strains were detected in irradiated groups compared with G1_control. Conclusions: The increase in roughness on dental enamel surfaces was proportional to the irradiation conditions. However, the increase in surface roughness caused by Er:YAG laser irradiation did not affect Streptococcus mutans and S. sanguinis adhesion.

Changes in deciduous and permanent dentinal tubules diameter after several conditioning protocols: In vitro study.

Innovators conditioning protocols are emerged in permanent dentin, however for deciduous dentin the information is limited; the aim of this study was to evaluate in vitro diameter of deciduous and permanent dentinal tubules after several conditioning protocols. Eighty dentin samples were distributed in sixteen groups (n = 5 p/g) and dentin surface was conditioned as follow: G1D/G1P acid etching; G2D/G2P, self-etch adhesive; G3D/G3P, G4D/G4P, Er: YAG laser irradiation at 200 mJ-25.5 J/cm2 and 300 mJ-38.2 J/cm2 , at 10 Hz under water spray respectively; G5D/G5P, G6D/G6P, G7D/G7P, and G8D/G8P were irradiated under the same energy densities followed phosphoric acid or self-etch adhesive conditioning. The sample dentin of deciduous and permanent teeth was analyzed with scanning electron microscopy and tubule diameter was evaluated by Image Tools Scandium program. Data were subjected to one-way analysis ANOVA to compare among groups with a level of significance at p ≤ .05. For deciduous dentin, diameters were from 1.52 ± 0.32 µm in G3D to 3.88 ± 0.37 µm in G1D; narrowest and widest diameter, respectively (p < .000). While permanent dentin tubules exhibited diameters from 1.16 ± 0.16/1.19 ± 0.12 µm in G7P/G8P to 2.76 ± 0.28 µm in G6P; narrowest and widest diameter, respectively (p < .000). All dentin conditioning protocols produced more open dentin tubules (diameter size) in deciduous dentin than permanent, specific conditioning protocols are required for each tissue (deciduous or permanent dentin), since same protocol produced stronger effects on primary dentin, which is important for dental clinical success in children and adolescents.

Morphological and chemical changes in human deciduous dentin after phosphoric acid, self-etching adhesive and Er: YAG laser conditioning.

The morphological and chemical changes in deciduous dentin produced by different conditioning protocols were evaluated in this in vitro study. Eighty primary dentin samples were divided into eight groups (n = 10): G1, acid etching; G2, self-etching adhesive; G3, G4, Er: YAG laser irradiation at 25.5 and 38.2 J cm-2 , respectively; 10 Hz and spray irrigation. Groups 5, 6, 7, and 8 were irradiated at previous densities, and then phosphoric acid or self-etching adhesive conditioning was applied. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were used to evaluate chemical and morphological changes. Paired t-test and One-way ANOVA were used for statistical analysis (p ≤ 0.05). All samples showed different morphology with specific characteristics according to the conditioning protocol. Changing element concentration values are expressed in atomic percent (at %). After conditioning, there were statistically significant differences (p ≤ 0.05) for p at% and Ca/P in all groups; highlighting the following additional findings by group: G1, G7, and G8 showed changes in all elements studied, G2 presented a decrease in C at% and increased Ca at%, G3 and G4 exhibited at% changes in C, trace elements and Ca. Furthermore, G5 showed at% changes in O and trace elements; while G6 changes were observed on C at%, O at% and trace elements at%. Dentin morphology and chemical composition varied in accordance with the conditioning protocol, with characteristics specific for each one that could have clinical implications for the retention and bond strength performance of adhesive materials.

Chemical and morphological changes in human dentin after Er:YAGlaser irradiation: EDS and SEM analysis.

Sixty samples of human dentin were divided into six groups (n = 10) and were irradiated with Er:YAG laser at 100 mJ-19.9 J/cm(2), 150 mJ-29.8 J/cm(2), 100 mJ-35.3 J/cm(2), 150 mJ-53.0 J/cm(2), 200 mJ-70.7 J/cm(2), and 250 mJ-88.5 J/cm(2), respectively, at 7 Hz under a water spray. The atomic percentages of carbon, oxygen, magnesium, calcium, and phosphorus and the Ca-to-P molar ratio on the dentin were determined by energy dispersive X-ray spectroscopy. The morphological changes were observed using scanning electron microscopy. A paired t-test was used in statistical analysis before and after irradiation, and a one-way ANOVA was performed (P ≤ 0.05). The atomic percent of C tended to decrease in all of the groups after irradiation with statistically significant differences, O and Mg increased with significant differences in all of the groups, and the Ca-to-P molar ratio increased in groups IV, V, and VI, with statistically significant differences between groups II and VI. All the irradiated samples showed morphological changes. Major changes in the chemical composition of dentin were observed in trace elements. A significant increase in the Ca-to-P ratio was observed in the higher energy density groups. Morphological changes included loss of smear layer with exposed dentinal tubules. The changes produced by the different energy densities employed could have clinical implications, additional studies are required to clarify them.

Mechanical, antibacterial and bond strength properties of nano-titanium-enriched glass ionomer cement.

The use of nanoparticles (NPs) has become a significant area of research in Dentistry. Objective The aim of this study was to investigate the physical, antibacterial activity and bond strength properties of conventional base, core build and restorative of glass ionomer cement (GIC) compared to GIC supplemented with titanium dioxide (TiO2) nanopowder at 3% and 5% (w/w). Material and Methods Vickers microhardness was estimated with diamond indenter. Compressive and flexural strengths were analyzed in a universal testing machine. Specimens were bonded to enamel and dentine, and tested for shear bond strength in a universal testing machine. Specimens were incubated with S. mutans suspension for evaluating antibacterial activity. Surface analysis of restorative conventional and modified GIC was performed with SEM and EDS. The analyses were carried out with Kolmogorov-Smirnov, ANOVA (post-hoc), Tukey test, Kruskal-Wallis, and Mann Whitney. Results Conventional GIC and GIC modified with TiO2 nanopowder for the base/liner cement and core build showed no differences for mechanical, antibacterial, and shear bond properties (p>0.05). In contrast, the supplementation of TiO2 NPs to restorative GIC significantly improved Vickers microhardness (p<0.05), flexural and compressive strength (p<0.05), and antibacterial activity (p<0.001), without interfering with adhesion to enamel and dentin. Conclusion GIC supplemented with TiO2 NPs (FX-II) is a promising material for restoration because of its potential antibacterial activity and durable restoration to withstand the mastication force.

Mechanical, antibacterial and bond strength properties of nano-titanium-enriched glass ionomer cement

The use of nanoparticles (NPs) has become a significant area of research in Dentistry. Objective The aim of this study was to investigate the physical, antibacterial activity and bond strength properties of conventional base, core build and restorative of glass ionomer cement (GIC) compared to GIC supplemented with titanium dioxide (TiO2) nanopowder at 3% and 5% (w/w). Material and Methods Vickers microhardness was estimated with diamond indenter. Compressive and flexural strengths were analyzed in a universal testing machine. Specimens were bonded to enamel and dentine, and tested for shear bond strength in a universal testing machine. Specimens were incubated with S. mutans suspension for evaluating antibacterial activity. Surface analysis of restorative conventional and modified GIC was performed with SEM and EDS. The analyses were carried out with Kolmogorov-Smirnov, ANOVA (post-hoc), Tukey test, Kruskal-Wallis, and Mann Whitney. Results Conventional GIC and GIC modified with TiO2 nanopowder for the base/liner cement and core build showed no differences for mechanical, antibacterial, and shear bond properties (p>0.05). In contrast, the supplementation of TiO2 NPs to restorative GIC significantly improved Vickers microhardness (p<0.05), flexural and compressive strength (p<0.05), and antibacterial activity (p<0.001), without interfering with adhesion to enamel and dentin. Conclusion GIC supplemented with TiO2 NPs (FX-II) is a promising material for restoration because of its potential antibacterial activity and durable restoration to withstand the mastication force. .

Alteration of metabolomic profiles by titanium dioxide nanoparticles in human gingivitis model.

Although nanoparticles (NPs) has afforded considerable benefits in various fields of sciences, several reports have shown their harmful effects, suggesting the necessity of adequate risk assessment. To clarify the mechanism of titanium dioxide nanoparticles (TiO2 NPs)-enhanced gingival inflammation, we conducted the full-scale metabolomic analyses of human gingival fibroblast cells treated with IL-1ß alone or in combination with TiO2 NPs. Observation with transmission electron microscope demonstrated the incorporation of TiO2 NPs into vacuoles of the cells. TiO2 NPs significantly enhanced the IL-1ß-induced prostaglandin E2 production and COX-1 and COX-2 protein expression. IL-1ß reduced the intracellular concentrations of overall primary metabolites especially those of amino acid, urea cycle, polyamine, S-adenosylmethione and glutathione synthetic pathways. The addition of TiO2 NPs further augmented these IL-1ß-induced metabolic changes, recommending careful use of dental materials containing TiO2 NPs towards patients with gingivitis or periodontitis. The impact of the present study is to identify the molecular targets of TiO2 NPs for the future establishment of new metabolic markers and therapeutic strategy of gingival inflammation.