In vitro study on the impact of various polishing systems and coffee staining on the color stability of bleach-shaded resin composite

OBJECTIVE

To evaluate the effects of different polishing techniques and coffee staining on the color stability of four commercially available bleach-shade composite resins, namely microhybrid, nanohybrid, nanofilled, and injectable nanohybrids.

MATERIAL AND METHODS

A total of 224 discs (8 mm diameter and 2 mm thickness) were fabricated from four different bleach-shade composite resins, namely microhybrid (Gradia Direct Anterior), nanohybrid (Palfique LX5), nanofilled (Filtek Universal), and injectable nanohybrid (flowable G-aenial universal injectable). The composite resin groups were polished via four techniques: no polishing, 4-step polishing using aluminum oxide discs, 3-step polishing using silicon rubber diamond discs, and one-step polishing. Half of each group was immersed in water, while the other half was immersed in coffee for 12 days (n = 7). Colors were measured using a clinical spectrophotometer, and color differences were calculated (ΔE). The results were analyzed statistically.

RESULTS

The alterations in color were significantly influenced by the techniques employed for finishing and polishing techniques, composite resin type, and degree of coffee staining. Regardless of the polishing technique and storage medium, different material types showed a significant color change (ΔE) at P < 0.001. Filtek exhibited the most significant color change, followed by Gradia and Palfique, with no significant differences between them. In addition, Different polishing techniques resulted in significant color changes (P < 0.001). The highest degree of color change was seen in the no-polishing group, followed by the 4-step and 1-step polishing groups, with negligible differences between each other. Also, Storage media had a significant effect on ΔE values.

CONCLUSION

Appropriate finishing and polishing procedures can improve the color stability of bleach-shaded composite resins. Coffee has a deleterious effect on color; however, injectable flowable nanohybrid composites are more resistant to staining.

A Comparative Evaluation of Surface Properties of Cention N and TiO2-Enriched Cention N After Brushing Simulation and Erosive Challenge: An In Vitro Study

Background This study aimed to evaluate and compare the abrasive and erosive wear resistance of Cention N and titanium dioxide (TiO2) nanoparticle-enriched Cention N after three years of brushing simulation. Methodology A total of 48 freshly extracted mandibular molars were mounted in acrylic blocks and divided into two groups of 24 molars based on the type of restorative material used to restore them. Cavities of a standardized size were prepared. Group A was restored with Cention N, and group B was restored with 5% TiO2-enriched Cention N. Each group was further divided into three subgroups of eight. Subgroup 1 was the control subgroup. Subgroup 2 was the abrasive subgroup, subjected to the abrasive challenge in a brushing stimulator with 30,000 cycles to 10,000 cycles in the linear X-axis and Y-axis each and another 10,000 cycles divided into 5,000 cycles clockwise and 5,000 cycles anticlockwise. The total number of brushing cycles was equal to three years of brushing with a duration of eight to nine hours. Subgroup 3 was the erosive and abrasive subgroup, subjected to an erosive pH cycle consisting of exposure to Coca‑Cola for five minutes thrice a day for seven days, and then subjected to brushing simulation as above. After the surface treatment, specimens were subjected to the Vickers microhardness test using a diamond indenter and the surface roughness test using an optical profilometer. The resulting values were subjected to statistical analysis. Results There was a significant decrease in mean surface roughness in group B, where TiO2 nanoparticles were added after erosive challenge and brushing simulation, than in group A. There was an increase in mean microhardness in group B which was not significant. Conclusions With the addition of 5% TiO2 to Cention N, there was a significant reduction in surface roughness. The surface microhardness of Cention N containing 5% TiO2 increased non-significantly compared to the control group.

Changes in Gloss Alteration, Surface Roughness, and Color of Direct Dental Restorative Materials after Professional Dental Prophylaxis

In the context of optimizing dental care for patients who are elderly, the purpose of this in vitro study was to evaluate the surface gloss (with a micro-area gloss meter) of, surface roughness (with a compact surface roughness measuring instrument) of, and color change (with a dental colorimeter) in two commercially available injectable resin-based composites (Estelite Universal Flow (EUF) and Beautifil Flow Plus F00 (BFP)) as well as two glass-ionomer cements (GC Fuji II LC CAPSULE (FLC) and GC Fuji IX GP EXTRA CAPSULE (FGP)), before and after dental prophylaxis. After 24 h, the surfaces of each specimen were polished at 2500 rpm with a prophy brush (Mersage Brush, Shofu) and one-step prophylaxis paste (Prophy Paste Pro, Directa): under 100 or 300 gf load, and for 10 or 30 s, 4× cycles of cleaning. After mechanical cleaning, conditions were found for a significant reduction in the gloss level (EUF, BFP, or FLC; p < 0.05) and a significant increase in surface roughness (BFP; 300 gf load, 10 s × four cycles of cleaning). Overall, the longer time or higher prophylaxis load tended to decrease the surface gloss. However, the observed change in surface roughness varied between the restorative materials. There was no color change post-prophylaxis.

Adhesion and Surface Roughness of Apatite-Containing Carbomer and Improved Ionically Bioactive Resin Compared to Glass Ionomers

The surface roughness of different glass-ionomer-based materials and their shear bond strength with a resin composite with and without thermal cycling were evaluated. Ketac Molar (KM, 3M ESPE, St. Paul, MN, USA), Glass Carbomer (GC, GCP Dental, Leiden, The Netherlands), Bioactive (BA, PULPDENT, Corporation, Watertown, MA, USA) and Fuji II LC (FJ, GC, Tokyo, Japan) were used to prepare the specimens and they were kept in distilled water at 37 °C for 24 h. The surface roughness of the specimens was measured with a profilometer (n = 6). A universal adhesive resin was applied on glass-ionomer materials and cylindrical universal composites were applied and polymerized, respectively (n = 16). The specimens were divided into two subgroups. The first subgroup was subjected to thermal cycling. Shear bond strength was investigated for both subgroups (n = 8). Stereomicroscopy and SEM examinations were performed. The roughest surface was obtained in the GC group (p < 0.05). The shear bond strength of the specimens without thermal cycling was higher than that of those with thermal cycling (p < 0.05). The lowest shear bond was measured in the GC group (p < 0.05). Although FJ, KM and BA have been observed to be suitable materials for clinical use, BA, in particular, is evidenced to become the best option among the materials we tested. GC cement's long-term performance needs to be improved.

The assessment of internal adaptation and fracture resistance of glass ionomer and resin-based restorative materials applied after different caries removal techniques in primary teeth: an in-vitro study

Background

The aim of this study was to evaluate the 3-dimensional (3D) internal adaptation (IA) and fracture resistance (FR) of compomer and glass ionomers applied after conventional caries removal to sound dentin (CCRSD) and selective caries removal to firm dentin (SCRFD) in in-vitro.

Methods

Thirty extracted primary molars were randomly assigned to three main groups (n = 10) as glass hybrid restorative (GHR) (Equia Forte® HT), conventional glass ionomer (CGIR) (Voco Ionofil Molar) and compomer (Dyract XP). Each group was randomly divided into two subgroups according to caries removal technique as CCRSD (n = 5) and SCRFD (n = 5). The restoration procedures were completed after caries removal (CCRSD or SCRFD) in all samples. Then, specimens were subjected to IA and FR tests. Data were analyzed with Student’s t, one-way ANOVA, and Kruskal Wallis-H tests. The correlation between IA and FR results was analyzed with a Pearson test. The statistical significance level was considered as 5%.

Results

While CCRSD showed superior IA results than SCRFD for all restorative materials (p < 0.05), no statistical difference was found between CCRSD and SCRFD in FR assessment (p > 0.05). In CCRSD, compomer showed superior results for IA and FR than glass ionomers (p < 0.05). In SCRFD, it was found no significant difference between the restoratives for IA (p > 0.05). However, compomer showed superior FR results than glass ionomers (p < 0.05). There was moderate negative correlation between internal voids and FR without statistically significant difference (r = −0.333, p = 0.072).

Conclusions

Despite the advantages of SCRFD, it was found to be less superior than CCRSD in IA assessment. Therefore, when SCRFD is preferred, a peripheral seal should be provided for ideal restorative treatment. On the other hand, compomer mostly showed superior results compared to others.

Periodontopathic bacterial adhesion to different restorative materials used to elevate proximal subgingival margins

This study compared the periodontopathic bacterial adhesion to four restorative materials used for deep margin elevation at 2, 24, and 48-h after incubation. Discs were produced from four restorative materials: resin modified glass ionomer, glass hybrid, flowable bulk fill resin composite, and bioactive ionic resin. Root dentin was used as control. Specimens were coated with saliva and used to culture a biofilm comprised of three strains of periodontopathic bacteria; Porphyromonas gingivalis, Prevotella intermedia, and Aggregatibacter actinomycetemcomitans. Bacterial adherence was assessed by colony count assay, crystal violet staining, and visualized using confocal laser scanning microscopy. Data were analyzed by two-way ANOVA followed by Tukey's post hoc tests. The adhesion values for the control specimens were significantly higher than for other materials, while those for the flowable bulk fill were significantly lower than for any other material within all evaluation assays. The 2-h incubation period showed the lowest adhesion values regardless of the group. The 48-h adhesion values were higher than the 24-h results in all groups except the flowable bulk fill. Microscopic imaging partially supported the findings of the measurements. In terms of periodontopathic bacterial adhesion, the tested flowable bulk fill may be preferable for subgingival use over other tested materials.

Surface roughness and oxygen inhibited layer control in bulk-fill and conventional nanohybrid resin composites with and without polishing: in vitro study

Background

It has been demonstrated that dental restorations with rough surfaces can have several disadvantages such as pigment retention or plaque accumulation, which can facilitate caries formation, color variation, loss of brightness, degradation of restoration, among others. The present study aimed to assess surface roughness in bulk fill and conventional nanohybrid resins with and without polishing, controlling the oxygen inhibited layer.

Methods

This in vitro and longitudinal experimental study consisted of 120 resin blocks of 6 mm diameter and 4 mm depth, divided into two groups: Bulk Fill (Tetric^® N-Ceram Bulk-fill, Opus Bulk Fill APS, Filtek™ Bulk Fill) and conventional nanohybrid (Tetric^® N-Ceram, Opallis EA2, Filtek™ Z250 XT). Each resin group was divided into two equal parts, placing glycerin only on one of them, in order to control the oxygen inhibited layer. Subsequently, the surface roughness was measured before and after the polishing procedure with Sof-Lex discs. The data were analyzed with the T-test for related measures, and for comparison between groups before and after polishing, the non-parametric Kruskal Wallis test with the Bonferroni post hoc was used, considering a significance level of p < 0.05.

Results

Before polishing, the resin composites with the lowest surface roughness were Opus Bulk Fill APS (0.383 ± 0.186 µm) and Opallis EA2 (0.430 ± 0. 177 µm) with and without oxygen inhibited layer control, respectively; while after polishing, those with the lowest surface roughness were Opus Bulk Fill APS (0.213 ± 0.214 µm) and Tetric N-Ceram (0.097 ± 0.099 µm), with and without oxygen inhibited layer control, respectively. Furthermore, before and after polishing, all resins significantly decreased their surface roughness (p < 0.05) except Opus Bulk Fill APS resin with oxygen inhibited layer control (p = 0.125). However, when comparing this decrease among all groups, no significant differences were observed (p < 0.05).

Conclusion

The Opus Bulk Fill APS resin with oxygen inhibited layer control presented lower surface roughness both before and after polishing, being these values similar at both times. However, after polishing the other bulk fill and conventional nanohybrid resins with and without oxygen inhibited layer control, the surface roughness decreased significantly in all groups, being this decrease similar in all of them.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-022-02297-w.

Influence of Manual and Ultrasonic Scaling on Surface Roughness of Four Different Base Materials Used to Elevate Proximal Dentin-Cementum Gingival Margins: An In Vitro Study

AIM

To evaluate and compare the effects of both manual and ultrasonic scaling on surface roughness of four different base materials, used for elevating dentin/cementum gingival margins of proximal cavities.

METHODS AND MATERIALS

Eighty human upper molars with compound Class II mesial cavities, with gingival margins 1 mm below the cemento-enamel junction (CEJ), were divided into four different groups according to the type of the base material used; resin-modified glass ionomer (RMGI), glass hybrid (HV-GIC), flowable bulk-fill resin composite (Bulk Flow) and bioactive ionic resin (Activa). This was followed by completing the restorations with the same resin composite. All materials were used according to the manufacturers' instructions. All groups were further subdivided into two subgroups according to the scaling technique: manual (hand) or ultrasonic. All restorative and scaling procedures were performed after fixation of specimens with acrylic beside neighboring teeth to simulate natural contact. The mean surface roughness (Ra, μm) of all specimens was measured quantitatively and qualitatively by a three-dimensional (3D) surface analyzer system at two stages; (1) after thermal cycling for 5000 cycles without scaling and (2) after scaling. Data were statistically analyzed using analysis of variance (ANOVA), Tukey post hoc tests, and paired sample t-tests (at α=0.05).

RESULTS

For baseline readings, the Bulk Flow group had the lowest Ra values, while HV-GIC group had the highest. RMGI and Activa groups had no statistical significant difference between their Ra values (p>0.05). For post scaling readings, hand scaling had significantly lower Ra values than ultrasonic scaling in all the material groups (p<0.05), except in the Bulk Flow group, where both scaling methods were not significantly different from each other (p>0.05).

CONCLUSION

Bulk Flow had the smoothest surfaces when cured against a matrix band compared with the other tested base materials. When hand and ultrasonic scaling methods were compared, the latter technique had more detrimental effect on the surface texture of the four tested base materials.

Retention Ability of a Glass Carbomer Pit and Fissure Sealant

Dental sealants are an excellent means to prevent pits and fissure decay. Currently, there are multiple commercially available sealant materials. The purpose of this study was to assess the retention of glass carbomer fissure sealant and the incidence of secondary caries over a period of 24 months in comparison with a resin-based sealant. Materials and Methods: We included 32 children in the study, with ages between six and eight years and an average age of 6.8 years old. For each child, we sealed four permanent molars (totaling 128 teeth). The study group was divided into sub-groups. Sub-group A was represented by 64 first permanent molars which underwent dental sealing procedures with composite resin-based fissure sealant, Helioseal F™, and sub-group B was represented by 64 first permanent molars which underwent dental sealing procedures with glass carbomer cement, GCP Glass Seal™. The sealants were assessed clinically at 6, 12, 18, and 24 months. Results: The 6-month follow-up evaluation showed no statistically significant differences between the two materials neither regarding sealant retention nor new carious lesions formation (p > 0.05). At the 12-month recall, 57 molars had good retention (89.06%) from sub-group A and 44 molars (68.75%) from sub-group B; there was a statistically significant difference (p = 0.0187) between the two treatment choices only regarding material retention. At the last recall after 2 years, sub-group A had a higher number of molars with perfect sealing (47–73.43%) and 8 molars (12.5%) with new caries lesions and sub-group B had 23 (35.93%) molars with perfect sealing and 15 molars (23.44%) with new caries lesions; there was a statistically significant difference (p < 0.0001) between the two treatment choices only regarding material retention. Conclusions: The glass carbomer retention is very inferior to the resin-based material. The glass carbomer sealant was effective in preventing new caries development, comparable with the conventional resin-based sealant.

Wear Behavior and Surface Quality of Dental Bioactive Ions-Releasing Resins Under Simulated Chewing Conditions

Bioactive materials can reduce caries lesions on the marginal sealed teeth by providing the release of ions, such as calcium, phosphate, fluoride, zinc, magnesium, and strontium. The presence of such ions affects the dissolution balance of hydroxyapatite, nucleation, and epitaxial growth of its crystals. Previous studies mostly focused on the ion-releasing behavior of bioactive materials. Little is known about their wear behavior sealed tooth under mastication. This study aimed to evaluate the wear behavior and surface quality of dental bioactive resins under a simulated chewing model and compare them with a resin without bioactive agents. Three bioactive resins (Activa, BioCoat, and Beautifil Flow-Plus) were investigated. A resin composite without bioactive agents was used as a control group. Each resin was applied to the occlusal surface of extracted molars and subjected to in vitro chewing simulation model. We have assessed the average surface roughness (Ra), maximum high of the profile (Rt), and maximum valley depth (Rv) before and after the chewing simulation model. Vickers hardness and scanning electron microscopy (SEM) also analyzed the final material surface quality). Overall, all groups had increased surface roughness after chewing simulation. SEM analysis revealed a similar pattern among the materials. However, the resin with polymeric microcapsules doped with bioactive agents (BioCoat) showed increased surface roughness parameters. The material with Surface Pre-reacted Glass Ionomer (Beautifil Flow-Plus) showed no differences compared to the control group and improved microhardness. The addition of bioactive agents may influence surface properties, impairing resin composites' functional and biological properties. Future studies are encouraged to analyze bioactive resin composites under high chemical and biological challenges in vitro with pH cycles or in situ models.

Antibacterial effects of saliva substitutes containing lysozyme or lactoferrin against Streptococcus mutans

OBJECTIVE

To determine the antibacterial effects of different saliva-substitutes-containing-lysozyme(LYZ) or-lactoferrin(LF) on Streptococcus mutans(S. mutans) in comparison with human saliva.

DESIGN

In vitro wound-healing assay was performed with L929 mouse fibroblast cell line by using various concentrations of LYZ and LF to determine optimum concentrations and to confirm do not show any cytotoxicity of proteins according to cell culture studies. Antibacterial effect was assessed by determining Minimum Inhibitory Concentrations for all groups on S.mutans. Bacterial adhesion of S. mutans for 4 h on hydroxyapatite(HAP) discs after application of different saliva substitutes was evaluated. The formulations were:saliva-substitute(Group SS);saliva-substitute-containing-Lactoferrin(Group SSLF);saliva-substitute-containing-Lysozyme(Group SSLYZ). Human saliva was control group(Group HS).

RESULTS

In vitro wound healing assay results showed that, when added into the cell culture media, LYZ and LF significantly increase 48 -h scratch wound closure compared to the cell culture media(p < 0.0001). At the end of second day, samples treated with both between 2.5-100 μg/mL LF and 5-200 μg/mL LYZ were found to have significant wound healing effect(p < 001). It was observed that saliva-substitutes-containing-LYZ or-LF had antibacterial effects on S.mutans. Bacterial adhesion on HAP discs was observed significantly higher in control group than in study groups. The amount of adhered S. mutans was significantly higher in Group SS than other study groups(p < 0.0001). However, no statistically significant difference was found between the number of bacteria adhered to HAP discs between SSLYZ and SSLF groups(p > 0.05).

CONCLUSIONS

The study of cell viability and wound healing was great significance in the optimum concentrations of LYZ and LF. Among formulations, saliva-substitutes-containing-LYZ or-LF exhibited higher inhibitory effect on S.mutans.

New Experimental Zirconia-Reinforced Rice Husk Nanohybrid Composite and the Outcome of Its Surface Roughness and Microhardness in Comparison with Commercialized Nanofilled and Microhybrid Composite Resins

Background:

An ideal composite resin should demonstrate smooth surface after polishing and high hardness value to provide long-term success. Thus, this study aimed to compare the surface roughness and microhardness of new experimental zirconia-reinforced rice husk nanohybrid composite (Zr-Hybrid) with commercialized nanofilled (Filtek-Z350-XT) and microhybrid composite (Zmack-Comp) resins before and after artificial ageing.

Methods:

One hundred and eighty standardized disc samples were prepared, of which ninety samples each were used for surface roughness and microhardness test, respectively. They were divided equally into: Group 1 (Filtek-Z350-XT), Group 2 (Zmack-Comp), and Group 3 (Zr-Hybrid). For surface roughness test, all samples were polished with aluminium oxide discs and further subdivided into aged and unaged subgroups, in which composite samples in aged subgroups were subjected to 2500 thermal cycles. Next, all the samples were subjected to surface roughness test using a contact stylus profilometer. As for microhardness test, all the aged and unaged samples were tested using a Vickers hardness machine with a load of 300 kgf for 10 s and viewed under a digital microscope to obtain microhardness value. Data were analyzed using two-way ANOVA followed by post hoc Tukey's honestly significant difference and paired sample t-test with significance level set at P = 0.05.

Results:

In both the aged and unaged groups, Zr-Hybrid showed statistically significantly lower surface roughness (P < 0.05) than Filtek-Z350-XT and Zmack-Comp, but no statistically significant difference was noted between Filtek-Z350-XT and Zmack-Comp (P > 0.05). A similar pattern was noted in microhardness test, whereby Zr-Hybrid showed the highest value (P < 0.05) followed by Filtek-Z350-XT and lastly Zmack-Comp. Besides, significant differences in surface roughness and microhardness were noted between the aged and unaged groups.

Conclusion:

Zr-Hybrid seems to demonstrate better surface roughness and microhardness value before and after artificial ageing.

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.

The effect of ionizing radiation on properties of fluoride-releasing restorative materials

The purpose of this study was to evaluate the effect of ionizing radiation from high energy X-ray on fluoride release, surface roughness, flexural strength, and surface chemical composition of the materials. The study groups comprised five different restorative materials: Beautifil II, GCP Glass Fill, Amalgomer CR, Zirconomer, and Fuji IX GP. Twenty disk-shaped specimens (8x2 mm) for fluoride release and 20 bar-shaped specimens (25 x 2x 2 mm) for flexural strength were prepared from each material. Each material group was divided into two subgroups: irradiated (IR) and non-irradiated (Non-IR). The specimens from IR groups were irradiated with 1.8 Gy/day for 39 days (total IR = 70.2 Gy). The amount of fluoride released into deionized water was measured using a fluoride ion-selective electrode and ion analyzer after 24 hours and on days 2, 3, 7, 15, 21, 28, 35, and 39 (n = 10). The flexural strength was evaluated using the three-point bending test (n = 10). After the period of measurement of fluoride release, seven specimens (n = 7) from each group were randomly selected to evaluate surface roughness using AFM and one specimen was randomly selected for the SEM and EDS analyses. Data were analyzed with two-way ANOVA and Tukey tests (p = 0.05). The irradiation significantly increased fluoride release and surface roughness for Amalgomer CR and Zirconomer groups (p < 0.05). No significant change in flexural strength of the materials was observed after irradiation (p > 0.05). The ionizing radiation altered the amount of fluoride release and surface roughness of only Amalgomer CR and Zirconomer. The effect could be related to the chemical compositions of materials.

Antibiofilm activities of fluoride releasing restorative materials

Backround/Aim: The purpose of this in vitro study is to evaluate the antibiofilm and antimicrobial activities of 5 different restorative materials that release fluoride. Material and Methods: Five different fluoride releasing restorative materials [Riva Self Cure (SDI, Australia), Riva Light Cure (SDI, Australia), Riva Silver (SDI, Australia), Dyract® XP (DENTSPLY, Germany) and Beautifil II (SHOFU, Japan)] and one composite resin material (Grandio, VOCO, Germany) were selected for this study. A total of 48 specimens (8 of each) were prepared using Teflon molds (4.0 mm-diameter and 2.0 mm-thickness). The antibacterial and antibiofilm activities of the mentioned restorative materials on Streptococcus mutans were evaluated. The data obtained were evaluated by One-Way analysis and Tukey's Test (p<0.05). Results: As a result, no correlation was found in terms of antibacterial and antibiofilm activities of the restorative materials evaluated in the study. While the dental plaque (matrix) accumulation was detected at least on the Grandio resin, the materials with the least cell adhesion were Light Cure and Riva Self Cure since it showed antiadhesive properties for S. mutans. Conclusions: Although the highest antibacterial activity against S. mutans was detected in resin-modified glass ionomers, biofilm matrix (dental plaque) accumulation was mostly detected on these material surface in our study.

Trans,trans-farnesol, an antimicrobial natural compound, improves glass ionomer cement properties

A series of experiments were conducted to characterize a novel restorative material. We explored the effect on biological, physical and chemical properties of glass ionomer cement (GIC) adding-the naturally occurring tt-farnesol (900 mM). Two groups were accomplished for all assays: GIC+tt-farnesol and GIC (control). Biological assays: 1) agar diffusion against some cariogenic bacteria; 2) S. mutans biofilm formation and confocal laser scanning microscopy-CLSM. 3) gtfB, gtfC, gtfD, gbpB, vicR, and covR expression; 4) MTT and microscopic morphology. Physical properties assays: 1) roughness; 2) hardness; 3) compressive strength and 4) diametral tensile strength. Chemical assay: Raman spectroscopy. The adding of tt-farnesol to GIC led to larger zones of inhibition (p<0.05), biofilms with a short-term reduction in bacterial viability but similar biomass (p>0.05). Polysaccharides levels increased over time, similarly over groups (p>0.05). Viable and non-viable S. mutans were seen on the specimens’ surface by CLSM but their virulence was not modulated by tt-farnesol. The tt-farnesol increased the HaCaT cell viability without impact on compressive and diametral tensile strength and roughness although the hardness was positively affected (p<0.05). Raman confirmed the presence of tt-farnesol. The incorporation of tt-farnesol into GIC inhibited the growth of cariogenic bacteria but had a little effect on the composition, structure and physiology of the biofilm matrices. Also, the tt-farnesol increased the hardness and the biocompatibility of the GIC, not influencing negatively other physical properties of the restorative material.

Fluoride release and uptake in enhanced bioactivity glass ionomer cement ("glass carbomer™") compared with conventional and resin-modified glass ionomer cements

Objectives

To study the fluoride uptake and release properties of glass carbomer dental cements and compare them with those of conventional and resin-modified glass ionomers.

Materials and Methods

Three materials were used, as follows: glass carbomer (Glass Fill), conventional glass ionomer (Chemfil Rock) and resin-modified glass ionomer (Fuji II LC). For all materials, specimens (sets of six) were matured at room temperature for time intervals of 10 minutes, 1 hour and 6 weeks, then exposed to either deionized water or sodium fluoride solution (1000 ppm in fluoride) for 24 hours. Following this, all specimens were placed in deionized water for additional 24 hours and fluoride release was measured.

Results

Storage in water led to increase in mass in all cases due to water uptake, with uptake varying with maturing time and material type. Storage in aqueous NaF led to variable results. Glass carbomer showed mass losses at all maturing times, whereas the conventional glass ionomer gained mass for some maturing times, and the resin-modified glass ionomer gained mass for all maturing times. All materials released fluoride into deionized water, with glass carbomer showing the highest release. For both types of glass ionomer, uptake of fluoride led to enhanced fluoride release into deionized water. In contrast, uptake by glass carbomer did not lead to increased fluoride release, although it was substantially higher than the uptake by both types of glass ionomer.

Conclusions

Glass carbomer resembles glass ionomer cements in its fluoride uptake behavior but differs when considering that its fluoride uptake does not lead to increased fluoride release.

Clinical Evaluation of Microhybrid Composite and Glass lonomer Restorative Material in Permanent Teeth

AIM

The aim of this study was to clinically compare glass ionomer cement (GIC) with microhybrid composite resin used in class I cavities on permanent teeth over a period of 9 months.

MATERIALS AND METHODS

A total of 40 teeth with class I cavities were divided into two groups (n = 20) and restored with GIC (EQUIA; GC) and microhybrid resin composite (Amelogen Plus; Ultradent). Restorations were evaluated at ×4.5 magnification using the United States Public Health Service (USPHS) criteria every 3 months. Statistical analysis was performed using the Fisher's exact test (a < 0.05).

RESULTS

The data obtained reported no statistical significance difference between both groups in regard to anatomical shape, color, postoperative sensitivity, secondary caries, material handling, adaptation, and marginal staining.

CONCLUSION

The results of this clinical study showed that GIC (EQUIA; GC) can be used for the restoration of permanent teeth and may be more appropriate for certain clinical situations than the resin composite material.

CLINICAL SIGNIFICANCE

EQUIA (GIC) is a viable alternative to resin composite in restoring class I cavities in permanent teeth.