High-viscosity Glass Ionomer Cement Research Articles

The clinical success of ART restorations and Hall technique in primary molars: a randomized 18-month follow-up study.

The aim of the study was to evaluate the clinical and radiographic success of the Hall technique (HT) and atraumatic restorative treatment (ART) restorations using high-viscosity glass-ionomer cement for the management of occlusal carious lesions in primary molars. This randomized clinical study observed 40 children (aged 5-6 years). For each child, one tooth was treated with HT and one with ART. The primary outcome measures for HT restorations were successful, minor, and major failure rates. Clinical evaluations of ART restorations were performed according to the modified United States Public Health Service criteria during 18-month follow-up. McNemar test was used for statistical analysis. Thirty of 40 (75%) participants returned for 18 months of follow-up. In the clinical evaluations of teeth that were treated with HT, the patients did not have complaints of pain or other symptoms, all crowns remained in the oral cavity, the gums were healthy, and the teeth were functional in all evaluations. At the end of the 18-month follow-up, the surface texture and marginal integrity criteria of ART restorations were recorded as 26.7% and 33.3%, respectively. In the radiographic evaluation of 30 patients treated with ART and HT, all restorations were considered successful. The 18-month clinical and radiographic results after treatments applied to single-surface cavities in anxious children showed that both treatment methods were successful.

Survival Rate of Atraumatic Restorative Treatment Restorations in Primary Posterior Teeth in Children with High Risk of Caries in the Republic of Kosovo-1-Year Follow-up.

Atraumatic restorative treatment (ART) may be beneficial for disadvantaged populations with no or limited access to dental services. This study aimed to evaluate the survival rate of single-surface ART restorations in primary posterior teeth in children with high caries risk. This study was conducted in six rural areas of the Republic of Kosovo, and 100 children aged 3 to 8 years participated in the study. Information was obtained from each parent/guardian regarding their children, such as sociodemographic characteristics, general health, dental history, dietary habits, oral hygiene, and fluoride exposure. The reduced Cariogram was used to estimate the risk of caries in the participants based on the seven factors specified in the program, and all the provided information were collected and entered in a computer program of the Cariogram. A pediatric dentist, accompanied by two assistants, performed 100 ART restorations in school settings using high-viscosity glass-ionomer cement (Fuji IX) following the nine steps of the ART procedure. The restorations were evaluated at 3, 6, 9, and 12 months using the ART restoration criteria. Percentages, mean value, standard deviation, mean interquartile range, and difference test between arithmetic mean values were used to analyze the research results. Review of the average of reduced Cariogram showed that the majority of children, 72%, were at high risk of developing caries, with only 28% having a good chance of avoiding caries in the future. A total of 77% of the children in the study had never visited dentists before due to poor economic conditions and the lack of dentists in the area. The success rates of ART restorations performed in single-surface cavities in primary teeth were very encouraging, with more than 97% success rates after a 1-year follow-up period. Our results demonstrate that ART is efficient, affordable, and practical for the treatment of single-surface cavities in primary posterior teeth. Owing to its low price and atraumatic nature, ART can potentially help disadvantaged children in Kosovo access dental care.

Effects of Protective Surface Coating on Fluoride Release and Recharge of Recent Uncoated High-Viscosity Glass Ionomer Cement.

The ability to release and recharge fluoride is a property of glass ionomer cement materials, which is an advantage for patients with a high caries risk. The purpose of this study was to evaluate the amount of released and recharged fluoride in recent uncoated high-viscosity glass ionomer cement (KetacTM Universal AplicapTM) with different surface coatings and at different time points. In total, 135 cylindrical-shaped specimens were equally divided into the following three groups: KetacTM Universal AplicapTM, KetacTM Molar AplicapTM, and KetacTM Fil Plus AplicapTM. The different coatings performed on each group were as follows: uncoated, coated with KetacTM Glaze, and coated with G-Coat PlusTM. The amounts of released and recharged fluoride were measured at 24 h and at weeks 1, 2, 3, and 4. The recharging agent was a 1.23% APF gel. KetacTM Universal AplicapTM showed the highest released fluoride at all time points and the highest recharged fluoride at weeks 1, 2, and 3. Both the KetacTM Glaze- and G-Coat PlusTM-coated specimens presented significantly lower released and recharged fluoride ions than the uncoated group at all time points (p < 0.001). Coating with G-Coat PlusTM significantly decreased the released and recharged fluoride compared to the coating with KetacTM Glaze at almost all time points (p < 0.05), except for weeks 1 and 2. The application of coating agents reduced the amount of released and recharged fluoride by the KetacTM Universal AplicapTM.

Does treating proximal cavities in primary molars non-restoratively affect intra-arch space and alignment of successor teeth negatively? A 4-year longitudinal study.

BackgroundRemoving plaque with toothbrush and toothpaste from proximal cavities in primary molars without restoring them follows sound cariological principles. But does this treatment affect space for and alignment of their permanent successors negatively?HypothesisThere is no difference in impaction and displacement of the premolars, as well as in the D+E space in quadrants with three different statuses of the proximal surface of primary molars over a 4-year period.MethodsA total of 936 quadrants (466 maxillary and 470 mandibular quadrants) in 233 children were assessed. Treatment of cavities in the proximal surfaces of the primary molars consisted of amalgam and ART restorations using high-viscosity glass-ionomer cement, and cleaning of open large- and medium-sized cavities with toothbrush and toothpaste (UCT) under supervision for 220 days per year over 3 years. Dental casts were made at baseline, and after two, three, and 4 years. The D+E spaces were measured digitally. Status of the proximal surface of the primary molars was assessed by two calibrated examiners, and quadrants were grouped into normal anatomy, defective restoration, and proximal cavity. ANCOVA, ANOVA and LSD tests were applied.ResultsThere was a statistically significant difference between groups (p <= 0.001) and between evaluation times (p < 0.001), for the D+E space in both the maxilla and mandible. A sex difference related to the D+E space in the maxilla was found (p = 0.007). For boys, quadrants in the maxilla of the group ‘proximal cavity’ showed a significant shorter D+E space when compared to quadrants of the group ‘normal anatomy’ at the 3- and 4-year evaluation time. For girls the difference between the two groups was only present at the 3-year evaluation time. There was no significant difference between the D+E space in quadrants with defective restorations and those with normal anatomy in the mandible and in the maxilla. Displacement and impaction of the premolars showed no significant difference between groups.ConclusionPrimary molars with open proximal cavities that are cleaned with toothbrush and toothpaste do not result in displacement and impaction of the successor teeth, neither do primary molars with defective restorations in proximal tooth surfaces.

Randomized Clinical Trial of Heated High Viscosity Glass Ionomer Class II Restorations in Deciduous Molars: 12 Months Follow Up

Objective: New generation High Viscosity Glass Ionomer Cements (HVGICs) have enhanced physical and mechanical properties. By effectively closing the restoration margin, it ensures that the restorations will last longer. The aim of this study was to investigate the clinical performances of heat-cured versus non heated HVGIC in class II restorations of deciduous molars. Methods: This randomized, split mouth, multicentre study was performed in four different centres. A total of 250 deciduous molars from 88 individuals were randomly allocated to one of the following groups: 1) non-heated (n = 125) 2) heated (n = 125) and restored with a HVGIC using LED light for heat application. Restorations were clinically evaluated according to the modified USPHS at the baseline, 6 months and 12 months. The survival analysis was performed by Kaplan Meier and Life Tables. This study was retrospectively registered to the ClinicalTrials.gov with the ID number of NCT04291872 at 2nd March 2020. Results: No statistically significant differences were found between the groups regarding to modified USPHS criteria (p&amp;gt;0.05). Success rate in retention criteria was 94.1% of the heat-cured and 92.6% of the non-heated restorations after 12 months. The mean survival time was 11.8 ±0.1 months in the heated group, while 11.9±0.1 months in the non-heated group. Conclusion: The heat treated HVGIC for Class II restorations did not show any significant differences in 12 months’ follow-up compared with the conventional technique.

Clinical Effectiveness of Restorative Materials for the Restoration of Carious Primary Teeth: An Umbrella Review.

Since untreated dental caries remain a worldwide burden, this umbrella review aimed to assess the quality of evidence on the clinical effectiveness of different restorative materials for the treatment of carious primary teeth. A literature search in electronic bibliographic databases was performed to find systematic reviews with at least two-arm comparisons between restorative materials and a follow-up period ≥12 months. Reviews retrieved were screened; those eligible were selected, and the degree of overlap was calculated using the ‘corrected covered area’ (CCA). Data were extracted and the risk of bias was assessed using the ROBIS tool. Fourteen systematic reviews with a moderate overlap (6% CCA) were included. All materials studied performed similarly and were equally efficient for the restoration of carious primary teeth. Amalgam and resin composite had the lowest mean failure rate at 24 months while high-viscosity and metal-reinforced glass ionomer cements had the highest. At 36 months, high-viscosity glass ionomer cements showed the highest failure rate with compomer showing the lowest. Most reviews had an unclear risk of bias. Within the limitations of the review, all materials have acceptable mean failure rates and could be recommended for the restoration of carious primary teeth.

Crown Reconstruction of Erosive Wear Using High-viscosity Glass Ionomer Cement: A Case Report

The aim of this clinical report is to present a possible alternative treatment, with 24-month follow-up, for restoring tooth loss due to extensive erosive tooth wear. A 21-year-old male patient, complaining of intense sensitivity in the maxillary posterior teeth, and presenting severe wear on maxillary premolar and molar teeth due to gastroesophageal reflux, sought care in the university clinics. The planned treatment was to refer for medical treatment and perform restorations with the high-viscosity glass ionomer cement Equia Forte (GC Corporation, Tokyo, Japan), aiming to restore the dental anatomy and to consequently decrease the pain symptomatology. A silicone guide, obtained from a diagnostic waxing, was used during the restorative approach considering the patient's occlusion. After all the clinical steps of the restorative technique, an occlusal adjustment of restorations was performed. During monthly recalls up to 24 months, the treatment was stable and in service. In addition, the patient reported no pain and improved chewing, leading to a better quality of life.

Microleakage of two different posterior composites and a high-viscosity glass-ionomer cement: An in vitro study

Aim: Using AutoCAD, we examined the microleakage of permanent molars in Class I restorations using a conventional posterior composite resin, a bulk-fill composite resin, and a high-viscosity glass-ionomer cement (HVGIC). Methodology: In total, 33 extracted noncarious third molars were used. Class I cavities were prepared. The teeth were randomly divided into three groups of 11 teeth each, as follows: Group A (Filtek Z550), Group B (Filtek Bulk-Fill Posterior Restorative), and Group C (EQUIA Fil). All specimens were stored for 24 h at 37 °C in distilled water. The teeth were thermocycled 1,000 times between 5 ± 2°C and 55 ± 2°C prior to immersion in 0.5% basic fuchsin for 24 h. Two mesiodistal cuts of each tooth were photographed under a stereomicroscope equipped with a digital camera. The dye-infiltrated surface area was measured. Results: Statistical evaluations were performed by one-way analysis of variance [ANOVA]. One-way ANOVA showed no significant difference between the three groups in microleakage (P = 0.07). However, the lowest microleakage ratio was seen in Group C (EQUIA Fil). Similar results were obtained with all tested materials, but the lowest microleakage rate was obtained with EQUIA Fil (Group C). Conclusion: In this study, the tested materials were not completely successful in eliminating microleakage, although the lowest microleakage rate was obtained with EQUIA Fil. How to cite this article: Çelenk S, Ataş O, Ayna B, Günay A. Microleakage of two different posterior composites and a high-viscosity glass-ionomer cement: An in vitro study. Int Dent Res 2022;12(1):34-8. https://doi.org/10.5577/intdentres.2022.vol12.no1.6 Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

Assessment of the effects of different dental restorative materials on radiotherapy dose distribution: A phantom study.

One of the most specific effects of high-density dental restorative materials on head & neck cancer radiotherapy is generating variations on isodose distributions. These variations might have an impact on the accuracy and effectiveness of the radiation treatment. The aim of this study is investigating the possible dosimetric effect of six different restorative materials on isodose distributions in head & neck radiotherapy planning process. A special phantom was developed and twenty-one caries-free human third molars (a control group + six different restorative materials) were used for the measurements. After acquiring the computed tomography (CT) images, seven treatment plans were created. Hounsfield Unit (HU) numbers, horizontal line dose profile (HLDP) and vertical line dose profiles (VLDPs) were compared with the control group. The amalgam sample deformed the HU numbers in CT images. The median HU value for the S4 material was considerably different than the other samples. The median values were quite close for the remaining samples. For the amalgam sample, the mean of the calculated median isodose values for HLDP and VLDP at 3.5 cm away from the isocenter line were lower than the mean of the control group 4.03% and 6.94%, respectively (for HLDP with tooth numbers of 36 and 38 P = 0.025 and P < 0.001, respectively; for VLDP P < 0.001). In C-S1 comparison results, the statistically significant differences were found for the measurement point at 1 cm away from the isocenter (P = 0.037, P = 0.002, and P = 0.018 for the tooth numbers 36, 37, and 38, respectively). In C-S2 and C-S6 comparisons, there was a statistically significant difference for tooth number 36 (P = 0.035 and P = 0.003, respectively). The findings of the present study showed that amalgam should not be used in head & neck cancer patients who are planned to have radiation therapy. A high viscosity glass ionomer cement (GIC) and a ceramic reinforced GIC sample can be used instead of amalgam to minimize the distorting effect on isodose distributions.

Chlorhexidine gluconate enhances the remineralization effect of high viscosity glass ionomer cement on dentin carious lesions in vitro

BackgroundTo compare the mean mineral density (MMD) and examine the remineralization of carious dentin after cavity disinfection with chlorhexidine gluconate (CHX) and restoration with high viscosity glass ionomer cement (H-GIC) in vitro.MethodsSelective caries removal to leathery dentin was performed in 40 extracted primary molars. The samples were scanned using micro-computed tomography (micro-CT) to determine the MMD baseline and randomly divided into 4 groups (n = 10): Equia™ group, applied dentin conditioner and restored with H-GIC (Equia Forte™), CHX-Equia™ group, disinfected the cavity with 2% CHX before applying dentin conditioner and restored with H-GIC (Equia Forte™), Ketac™ group, restored with H-GIC (Ketac Universal™) and CHX-Ketac™ group, disinfected the cavity with 2% CHX before restored with H-GIC (Ketac Universal™). The samples underwent micro-CT scanning post-restoration and post-pH-cycling to determine their respective MMDs. One sample from each group was randomly selected to analyze by scanning electron microscopy (SEM).ResultsThe MMD gain in the 4 groups post-restoration was significantly different between the Equia™ and CHX-Ketac™ groups (oneway ANOVA with Post hoc (Tukey) test, P = 0.045). There was a significant difference in MMD gain post-restoration between the Equia™ and CHX-Equia™ groups (Independent t-test, P = 0.046). However, the Ketac™ and CHX-Ketac™ group’s MMD were similar. The SEM images revealed that the CHX-Ketac™ group had the smallest dentinal tubule orifices and the thickest intertubular dentin among the groups. However, the CHX-Equia™ group had thicker intertubular dentin than the Equia™ group.ConclusionApplying 2% CHX on demineralized dentin enhances the remineralization of the dentin beneath the restoration.

Influence of pH Cycling on Erosive Wear and Color Stability of High-Viscosity Glass Ionomer Cements.

The purpose of this in vitro study was to evaluate erosive wear and change in color of high-viscosity glass ionomer cements after pH cycling in two erosive media. There were 3 experimental groups with 22 samples each, (I) EQUIA Forte HT without coat, (II) Fuji IX and (III) Ketac Universal Aplicap. Each group was randomly divided into three subgroups (n = 6–8) further exposed to different environments, (1) distilled water, (2) green tea (pH 3.78) and (3) Aceto balsamico vinegar (pH 3.0). Mass and L* a* b* values were recorded before and after pH cycling. The samples in subgroups 2 and 3 were exposed to the acidic media two times a day for 10 min, over a period of 14 days. The differences among materials and erosive effects of the three media were tested using three-way analyses of variance with post hoc LSD test at the significance level p < 0.05. The effect of pH cycling in Aceto balsamico and green tea was degrading for all three materials. pH cycling in Aceto balsamico caused significantly higher erosive wear than pH cycling in Fuzetea and storage in distilled water, in all materials (p < 0.05). pH cycling in both acidic media and in the control group resulted in a significant change in L* a* and b* (p < 0.05). The L* value decreased significantly and the a* and b* values increased significantly (p < 0.05).

Resistência à tração diametral de cimentos de ionômero de vidro convencionais modificados na razão de pó para uso em tratamento restaurador atraumático

ABSTRACT Objective: To identify the diametral tensile strength of Brazilian brands of conventional glass ionomer cements (GIC) when modified powder ratio in their composition compared to each other, and with high viscosity glass ionomer cement for Atraumatic Restorative Treatment (ART). Methods: Experimental study with five groups (n=10 each) and specimens (2.5 mm in height and 5.0 mm in diameter), considering G1 (Maxxion R-MR), G2 (Vidrion R-VR) and G3 Vitro molar (VM-control) according to manufacturer recommending powder/liquid (1:1), G4 (MR) and G5 (VR) plus powder (2:1). The specimens were stored in an oven at 37 ± 1 ° C for 1 day. Diametral Tensile Test was performed by the Instron model 4444. Means differences were tested by Student´s T-Test (α = 5%). Results: There significant differences were in the means (standard deviation) of diametral tensile strength of MR (1:1) 4.24 (±1.47) and MR (2:1), 5.74 (±1.51) (p=0.039) and VR (1:1) 4.50 (±1.27) and VR (2:1) 6.20 (±1.89) (p=0.029). When comparing MR and VR (2:1) with MV (1:1) 4.82 (±1.17), VR 2: 1, 6.20 (±1.89) showed significant differences (p=0.0336). Conclusion: There was a significant increase in the means of diametral tensile strength of Brazilian brands conventional GICs when powder increment, approaching the performance observed by the high viscosity GIC.

13 - Recycling of High-Viscosity Glass Ionomer Cement Plastic Capsules

This study aimed to show the chemical recycling process of glass ionomer cement capsules (Chemfil Rock, Dentsply). The process included acetone to attack polystyrene, separation of the dye (Rhodamine B) inside the polymer, and photodegradation by TiO 2 nanoparticles. The chemical reaction of the acetone solvent with the polystyrene degraded the material as power, but with the dye. The centrifugation technique separated the polystyrene from Rhodamine B dissolved in acetone. After that, the mixture was placed on the stove to evaporate the acetone and the dye was mixed with water and 10 mg of TiO 2 nanoparticles. The solution was exposed to UV radiation for 1 hour. Discoloration of the solution showed that Rhodamine B was degraded by TiO 2 nanoparticles. XRD confirmed the presence of crystalline anatase TiO 2 . FTIR analysis confirmed the existence of polystyrene organic groups in the powder resulting from centrifugation. This process was a feasible possibility to decrease the plastic residues of dental material capsules.

Comparison of Surface Roughness and Microhardness of Reinforced Glass Ionomer Cements and Microhybrid Composite

Objectives: The purpose of this study was to compare high viscosity glass ionomer cement (HVGIC), giomer and microhybrid composite using the atomic force microscopy (AFM) and Vickers microhardness. Methods: Three different restorative materials Equia Forte (HVGIC), Beautifil II (giomer) and Solare X (microhybrid composite)were used in this study. A total of 30 samples were prepared, 10 of each of the restorative materials used in our study. Samples were prepared using standard cylindrical Teflon molds with a diameter of 8 mm and a height of 2 mm. The measurements of surface roughness and hardness were performed by using AFM and Vickers microhardness, respectively. The surface roughness was analyzed using the Kruskal Wallis test. One-way variance analysis (ANOVA) and LSD test was used for the surface hardness (α = 0.05). Results: There was no significant difference between the groups according to surface roughness values (p&gt; 0.05). A statistically significant difference was found between all groups in terms of surface hardness. Conclusion: Reinforced glass ionomer cements had similar and surface properties than composite resin.

Children’s self-reported discomfort of restorative treatments for deep caries lesions in primary teeth: Results from a randomized clinical trial

The aim of this study was to evaluate the impact of different restorative techniques to treat deep caries lesions of primary molars on children’s self-reported discomfort. A randomized clinical trial with two parallel arms (1:1) was conducted in São Paulo, Brazil. 4-8 years-old children with at least one occlusal or occlusoproximal deep caries lesion in primary molars were selected. Molars were randomly allocated into two groups: (1) restoration performed with calcium hydroxide cement followed by high-viscosity Glass Ionomer Cement (CHC+HVGIC), and (2) HVGIC restoration. Immediately after the intervention, children reported the experienced discomfort during restoration to an external examiner using a Wong-Baker face-scale. Children’s self-reported discomfort was analyzed using Poisson regression comparing both groups and assessing other variables’ influence (α=5%). One hundred and eight children fulfilled the eligibility criteria and were randomized in the two groups (n=54). Most of the children who received CHC+HVGIC restorations reported none or minimal discomfort (83.3%). Similar scores (92.6%) were reported for those treated with HVGIC (p=0.758). The mean reported discomfort in children with CHC+HVGIC restorations was 0.37(1.01), and 0.41(1.01) for those with HVGIC restorations. Children’s self-reported discomfort was associated with age, sex, children’s cooperation, and intervention duration. We can conclude that CHC+HVGIC or HVGIC restorations result in none or minimal discomfort in the management of deep caries lesions, being considered a reliable option.

Evaluation of Class II Restoration Microleakage with Various Restorative Materials: A Comparative In vitro Study.

Background and Objectives:The quest for a suitable esthetic material for tooth restoration has resulted in significant advancements in both material properties and application technique. Composites and acid-etch procedures are two significant advancements in esthetic restorative dentistry. Further research has strengthened composites' overall wear resistance and strength, but the problem of polymerization shrinkage has persisted. To reduce polymerization shrinkage and microleakage, a variety of techniques and material modifications have been suggested. The marginal leakage of amalgam, packable composite, flowable composite with packable composite, and high-viscosity traditional glass ionomer cement (GIC) was compared in this analysis to test the mentioned hypothesis.Materials and Methods:We chose 60 freshly extracted teeth and divided them into four classes of 15 teeth each. Class II cavities were prepared in a standardized manner. Group I was treated with amalgam, Group II with packable composite (GC G-aenial Posterior), Group III with flowable composite (G-aenial Universal Flo) as a liner and then restored with packable composite (GC G-aenial Posterior), and Group IV with high-viscosity traditional GIC (EQUI FORTE FILL). After that, the restorations were put through a thermocycling process. The specimens were soaked in 0.5% methylene blue dye before being cut into mesiodistal sections to assess microleakage at the gingival margin. After that, the parts were examined under a stereomicroscope. The degree of dye penetration was used to determine the score.Results:There was no microleakage in the control group, and the gap between the control and experimental groups was statistically significant (P = 0.017).Conclusion:The glass hybrid restorative device had less gingival microleakage than the resin-based restorative material, indicating that it has a better sealing capacity. Clinical acceptability of glass hybrid restorative systems, on the other hand, must be confirmed with a larger sample size and in vivo trials.

Using Proanthocyanidin as a Root Dentin Conditioner for GIC Restorations

Glass ionomer cements (GICs) are considered the material of choice for restoration of root carious lesions (RCLs). When bonding to demineralized dentin, the collapse of dentinal collagen during restorative treatment may pose challenges. Considering its acidic nature and collagen biomodification effects, proanthocyanidin (PAC) could be potentially used as a dentin conditioner to remove the smear layer while simultaneously acting to biomodify the dentinal collagen involved in the bonding interface. In this study, 6.5% w/v PAC was used as a conditioner for sound (SD) and laboratory demineralized (DD) root dentin before bonding to resin-modified GIC (FII), casein phosphopeptide–amorphous calcium phosphate (CPP-ACP)–modified GIC (FVII), or a high-viscosity GIC (FIX). Root dentin conditioned with deionized distilled water (DDW) or polyacrylic acid (PAA) served as controls. Results indicated FII showed higher shear bond strength (SBS) on SD than the other 2 GICs, especially in PAA-conditioned samples; FIX showed significantly higher SBS than FII and FVII on PAA- or PAC-conditioned DD. In each category of GIC, PAA and PAC did not have a significant influence on SBS in most cases compared to DDW except for a significant decrease in PAC-conditioned SD bonded to FII and a significant increase in PAA-conditioned DD bonded to FIX. The bonding interface between GIC and SD was generally more resistant to the acid-base challenge than DD. Although the alterations in failure modes indicated a compromised interfacial interaction between GICs and PAC-treated root dentin, biomodification effects of PAC on dentin were observed from Raman microspectroscopy analysis in terms of the changes in mineral-to-matrix ratio and hydroxyproline-to-proline ratio of dentin adjacent to the bonding interface, especially of DD. Results from this study also indicated the possibility of using in situ characterization such as Raman microspectroscopy as a complementary approach to SBS test to investigate the integrity of the bonding interface.

Mechanical Assessment of Glass Ionomer Cements Incorporated with Multi-Walled Carbon Nanotubes for Dental Applications

Background: Nanoparticles such as multi-walled carbon nanotubes present resistance, resilience and biocompatibility with human tissues and could be incorporated into glass ionomer cement materials to improve their characteristics. Therefore, the aim of the present study was to evaluate the effect of multi-walled carbon nanotube (MWCNT) incorporation on different glass ionomer cements’ compressive (σc) and diametral tensile strengths (σt). Methods: Eighty (80) specimens were divided into four groups (N = 20/gr) according to the glass ionomer cement type (conventional and high-viscosity) and the presence or absence of multi-walled carbon nanotubes. Samples were kept in water for 24 h prior to the tests. Data were analyzed using two-way ANOVA and Tukey’s test (p = 0.05). Results: For both σc (p = 0.1739) and σt (p = 0.2183), the glass ionomer cements’ viscosity did not influence the results. The presence of MWCNTs decreased the mean compressive strength values (p = 0.0001) and increased the diametral tensile strength (p = 0.0059). For both conventional and high-viscosity glass ionomer cements, the compressive strength values were higher than the tensile strength data. Conclusions: Regardless of the cement viscosity, the multi-walled carbon nanotube incorporation reduced the compressive strength and increased the tensile strength values.

Comprehensive characterisation of flexural mechanical properties and a new classification for porosity of 11 contemporary ion-leaching dental restorative materials

The objectives of this study were to evaluate 4 aspects of ion-leaching restorative materials (ILMs): 4-point bending flexural strength (4 PB-FS) and relative mechanical properties; biaxial flexural strength (B-FS) in relation to 4 PB-FS; porosity; and surface morphology. Eleven ILMs were used for the 4-point bending test. Bar-shaped (n = 15) samples were fabricated, stored in distilled water for 7 days. Then 4 PB-FS and the other mechanical properties were determined. Five ILMs were selected for the B-FS test using disk specimens (n = 15). The correlation between 4 PB-FS and B-FS was addressed. After the 4 PB test, 5 randomised fragments from each material were used to make 0.5 mm-thick sections for light microscopy to investigate the degree of porosity using reflected and transmitted lights. Eight ILMs were selected for quantitative analysis of the fractional % pore volume (PV%) due to their relative pore prominence using ImageJ software. One-way ANOVA/Dunnett's T3 was used to test for significance. Resin-based ILMs (RB-ILMs) were ranked first (p < 0.05) for 4 PB-FS values (53.3–110.2 MPa) followed by resin-modified glass-ionomer cements (RMGICs; 30.9–44.3 MPa) and high-viscosity glass-ionomer cements (HVGICs; 12.9–19.6 MPa), respectively. ‘Flexural modulus’ (4 PB-E) and ‘flexural toughness’ (4 PB-T) of ILMs varied even though similar 4 PB-FS values were observed. There was a positive correlation (p < 0.001) between 4PB-FS and B-FS (R2 = 0.992) with B-FS>4 PB-FS. There was no correlation between PV% and 4 PB-FS. In summary, material type played a major role in 4 PB-FS outcomes, whereas PV% seemed to have a minor effect when evaluating each material group of ILMs. Brittleness/ductility of ILMs was observed when determining 4 PB-E and 4 PB-T relative to 4 PB-FS. When selecting materials for posterior load-bearing dental restorations in high-caries risk patients, RB-ILMs or RMGICs would be more appropriate due to their superior flexural properties compared with recently introduced HVGICs. The decision for each situation will also be dependent on further evidence of the ion-leaching capacity.

A Comparison Of Surface Roughness Values of Various Restorative Materials Immersed in Pedodontic Pre- and Probiotics

The present in vitro study aims to evaluate pre- and probiotic liquids' effect on surface roughness values of restorative materials after one month of immersion. 360 disc-shaped samples (5mm x 2mm) were prepared from two types of glass-ionomer cements (GIC), a resin-modified GIC, a compomer, three bulk-fill composites, and one microhybrid composite. After the surfaces were polished, samples were divided into three groups (n = 15) and immersed for 10 minutes daily for one month in either a probiotic sachet, kefir (prebiotic), or artificial saliva. After that, the surface roughness values were measured by a profilometer. Scanning electron microscopy (SEM) evaluations of one sample from tested materials were also added. Statistical data were analyzed using one-way ANOVA and Bonferroni–Dunn tests. One of the GIC materials had significantly rougher surfaces in the probiotic sachet, followed by the compomer (p &lt; 0.05). The compomer showed the roughest surfaces after immersion in kefir, followed by the microhybrid composite (Z250). Probiotic sachets formed rougher surfaces than kefir among samples. SEM images revealed the inorganic filler structures and microcracks on the surfaces. A high-viscosity glass-ionomer cement, Equia Fil Forte, and other composite-based materials tested in the present study can be used in pediatric patients who use pre- and probiotic supplements.