Comparative Evaluation of Shear Bond Strength of Various Glass Ionomer Cements to Dentin of Primary Teeth: An in vitro Study

Current Trends for Cementation in Prosthodontics: Part 1-The Substrate

With the vast possibilities of restorative dentistry nowadays and the constant development and release of restorative materials with improved mechanical and esthetical properties, there is a growing body of research on adhesive systems and cementation materials, as well as the adequate choices thereof in everyday clinical practice. There are high demands from the dental cements with regard to their adhesion to various substrates and restorative materials, their mechanical properties, resistance to dissolution in the oral environment, esthetic considerations, etc. A material that meets all these requirements is not yet available, and each available material presents certain shortcomings. However, thanks to the advancements in dental material research, polymers-based cements have gained admirable mechanical and esthetic properties, as well as versatility. With the plethora of products available on the market, clinicians are often faced with difficulties in the choice of a material adequate for certain clinical situations. Indeed, important factors to consider are the substrate for cementation and the restoration material. The aim of this review was to provide clear and literature-based clinical recommendations for the adequate cementation of prosthodontic restorations with regard to the cementation substrate. Considering that there is no gold standard protocol applicable in all clinical cases, since the properties of the cementation abutment could substantially differ, important individual considerations must be made for each situation.

An In vitro Comparative Analysis of the Shear Bond Value of Sixth, Seventh and Eight Generation Dentin Bonding Agents

Objective

This study evaluates the shear bond strength (SBS) of 6th, 7th, and 8th generation dentin bonding agents.

Materials and Methods

Thirty extracted premolars were divided into three groups of 10. Group A used a 6th generation bonding agent, Group B a 7th generation bonding agent, and Group C a 8th generation bonding agent. Each tooth was fixed in acrylic resin, sectioned to expose dentin, treated with the respective bonding agent, and built up with composite resin. SBS was assessed by universal testing machine.

Results

Highest shear bond value was illustrated by the 8th generation bonding agent, with subsequent values progressively lower for the 7th and 6th generation bonding agents.

Conclusion

The 8th generation bonding agents exhibit superior shear bond strength, suggesting enhanced dental restoration durability. Further clinical validation is recommended.

A Critical Review on the Factors Affecting the Bond Strength of Direct Restorative Material Alternatives to Amalgam

This article comprehensively reviews the performance of simplified direct restorative materials that have the potential to be an alternative to amalgam. Following an understanding of the material structures and clinical performances, this review provides an analysis of the bonding mechanisms and influential factors on the bond strength. These factors include substrate-related variations, involving primary vs. permanent dentin, sound- vs. caries-affected/demineralized dentin comparisons and surface-related factors and pretreatments. Special attention is given to the factors changing the substrate surface, such as different contaminants, remedy methods after contamination and different conditioning methods related to the materials. Variations in sample preparation and bond strength test parameters are also evaluated for the analysis of the outcomes. This review aims to provide an overview of the factors involved in the application procedure of direct restorations together with in vitro testing variations to guide the selection of suitable materials by understanding strengths and shortcomings.

An in vitro assessment of glass ionomer cement shear bond-strength to demineralized dentin in primary teeth treated with silver diamine fluoride and potassium iodide

Comprehensive caries therapy has relied on eliminating contaminated tooth structure and replacing it with restorative materials in pediatric dentistry. SDF with GIC can be administered together to stop the caries in cavitated lesions. Therefore, it is of interest to assess the shear bond strength of glass ionomer cement (type IX) to demineralized dentin in primary teeth treated with SDF and KI. The occlusal edges of sixty non-carious primary molar teeth were sliced until the yellow dentin was discernible. Each sample was embedded in an acrylic block with its occlusal surface facing upward after being submerged in a demineralizing solution for 7 days. Three groups were created from the samples: Group 1: The untreated group (control group) to which GIC type IX was placed directly; Group 2: Samples received immediate application of GIC type IX after getting treated with silver diamine fluoride (Experimental group) and Group 3: Silver diamine fluoride followed by potassium iodide followed by GIC type IX application (Experimental group). A Universal Testing Machine was subsequently utilized to perform a shear bond test on the specimens. Data shows that previously treated cement with SDF+KI increases the shear bond test without negatively impacted the bond strength GIC to dentin.

An In Vitro Evaluation of Mechanical Properties of a New Dual-cure, Universal, Bioactive Luting Cement

Aim and background

The aim of this study was to determine the properties of a new luting cement, BioCem®, by evaluating shear bond strength (SBS) and flexural strength (FS).

Materials and methods

A total of 60 extracted deciduous molars were included in this study. Samples were divided into two groups: Group I, Fuji I® (n = 30), and group II, BioCem® (n = 30). Each tooth was embedded in one acrylic block, such that the flattened enamel surface was exposed. Cylinders of 6 mm diameter and 8 mm height were prepared and evaluated for SBS using a universal testing machine. Ten rods of 25 × 2 × 2 mm of each material were prepared using a custom mold to evaluate the FS using a universal testing machine. Statistical Package for the Social Sciences (SPSS) version 20.0 was used for statistical analyses. Intergroup analysis was performed using an independent sample t-test.

Results

Upon comparing the SBS values of the luting agents and prepared enamel surfaces, glass ionomer cement (GIC) displayed the highest value, while BioCem® displayed the lowest. Upon comparing the FS values of the luting agents and prepared enamel surfaces, BioCem® performed better than GIC.

Conclusion

BioCem® may be used as a luting agent for the cementation of stainless steel crowns (SSCs) on primary teeth.

Clinical significance

BioCem®, a recently developed luting cement, may be used for cementing SSCs to the surfaces of prepared deciduous teeth; it exhibits significantly higher FS but lower SBS than that of GIC.

How to cite this article

Shams SA, Nekkanti S, Shetty S. An In Vitro Evaluation of Mechanical Properties of a New Dual-cure, Universal, Bioactive Luting Cement. Int J Clin Pediatr Dent 2024;17(8):887-891.

Effect of silver diamine fluoride and potassium iodide on shear bond strength for glass ionomer cement to primary dentine

Silver diamine fluoride (SDF) is a highly effective topical fluoride for halting dental caries; however, it darkens both teeth and restorations. Therefore, it is of interest to assess the shear bond strength (SBS) of glass ionomer cement (GIC) to caries-affected dentin treated with SDF alone and SDF followed by KI. Forty primary molar samples were prepared to reveal a flat dentin surface and were randomly assigned to two groups. In group A, the dentin surfaces were pre-treated with 38% SDF, while in group B, the dentin was treated first with SDF and then with KI before being restored with GIC. The SBS was measured using a universal testing machine. The results show that teeth pre-treated with both SDF and KI demonstrated significantly improved bond strength of GIC to dentin compared to SDF treatment alone.

Correlation between fluoride release, surface hardness and diametral tensile strength of restorative glass ionomer cements

Background

The aim of this study was to determine if there is a correlation between fluoride release, surface hardness, and diametral tensile strength of restorative glass ionomer cements (GICs).

Material and Methods

Conventional (Riva Self Cure) and resin-modified (Riva Light Cure) GICs were used. Thirty-four samples (ø 6 x 3 mm) were prepared for each cement. The kinetics of fluoride release (n=4) was evaluated over 28 days using a fluoride-selective electrode (ISE 4010-C00). The analysis of surface hardness (n=10) was performed using a microhardness tester (Shimadzu HMV-2000, Japan) with a Knoop indenter and a load of 25 gf for 30 seconds. The diametral tensile strength test (n=10) was conducted on a universal testing machine at a speed of 0.75 mm/min. Fluoride release data were analyzed by two-way repeated measures ANOVA and Bonferroni post hoc test, while independent t-test was used for other analyses (α=0.05).

Results

Overall, the groups showed higher fluoride release until day 7 and a progressive decrease until day 28. On day 1 and day 21, Riva Self Cure showed a higher level of release than Riva Light Cure (p=0.026). Riva Light Cure showed higher diametral tensile strength (p<0.0001) and surface hardness (p=0.034) than Riva Self Cure. A negative correlation was found, indicating that higher fluoride release is associated with lower surface hardness and diametral tensile strength.

Conclusion

Fluoride release and mechanical performance are related properties of GICs, and these properties exhibit different values depending on the type of material. Resin-modified GIC release less fluoride but exhibit better mechanical performance compared to conventional GIC. Key words:Diametral Tensile Strength, Fluoride, Glass Ionomer Cement, Surface Hardness.

A Comparative Evaluation of the Shear Bond Strength of Three Different Hybrid Tooth-Colored Restorative Materials to Dentin: An In-Vitro Study

INTRODUCTION

Silver amalgam, glass ionomer, resin-modified glass ionomer, compomers, light polymerized hybrid composite resin, and hybrid glass ionomer are among the most frequent restorative materials used as cavity-based or post-endodontics. Thus, to meet the needs of both patients and dentists, Cention N reimagines the traditional filling by integrating bulk placement, ion release, and durability into a dual-curing, aesthetically pleasing solution. Hoewver, we do not have enough information from studies comparing this hybrid restorative material's shear bond strengths to dentin to draw any firm conclusions. Cention N, zirconomer, and Vitremer are three hybrid tooth-colored restorative materials that were evaluated for their shear bond strength to dentin. This research aimed to compare and evaluate these materials.

METHODOLOGY

The purpose of this research was to use a universal Instron machine to measure the shear bond stress of three distinct hybrid tooth-colored restorative materials in relation to dentin. The research samples consisted of 45 extracted lower first premolars from humans. The teeth were then assigned into three groups of 15 samples each according to different color acrylic resin blocks, namely, group A (pink acrylic blocks), which had Cention in cement; group B (white acrylic blocks), which has zirconomer cement; and group C (violet acrylic blocks), which had Vitremer cement.

RESULTS

 There was no statistically significant difference between the three groups and the normal distribution, as shown by the negligible values in the tests involving the three groups. Put simply, each of the three categories exhibits data that follows a normal distribution. This allows for further data analysis to be conducted using the parametric test of significance.

CONCLUSION

The shear bond strength of hybrid glass ionomer restorative materials has to be further investigated in both laboratory and living organism settings.

Comparative evaluation of shear bond strength and modes of failure of five different reinforced glass ionomer restorative cements to TheraCal LC: An in vitro study

Aim

The aim of the study is to evaluate and compare the shear bond strength (SBS) and modes of failure of different reinforced glass ionomer cement restorative materials such as GC IX, GC Gold Label 2 LC, Amalgomer CR, Equia Forte, and Secure Core Z to TheraCal LC.

Methodology

A total of 50 acrylic blocks, each containing a cylindrical hole in the center were prepared from self-cure acrylic resin and randomly divided into five groups and restored, namely Group A - TheraCal LC + GC Fuji IX, Group B - TheraCal LC + GC Gold Label 2 LC, Group C - TheraCal LC + Amalgomer CR, Group D - TheraCal LC + Equia Forte, and Group E - TheraCal LC + Secure Core Z. All the specimens were stored in artificial saliva at 37°C for 24 h before testing. The statistical tests used for the analysis of the result were: one-way ANOVA, Tukey multiple comparison test, and the Chi-squared test, and P < 0.05 is considered as the level of significance.

Results

Equia Forte showed the highest SBS, while GC type IX showed the lowest SBS with TheraCal LC.

Conclusion

Equia Forte can be the restorative material of choice when TheraCal LC is used as a base materials for better clinical efficacy.

Evaluation of the effect of nano-graphene oxide on shear bond strength of conventional and resin-modified glass ionomer cement

OBJECTIVES

Recently, nano-graphene oxide (nGO), a material with unique mechanical properties, has been introduced to improve the properties of glass ionomer cement (GIC). The purpose of this study was to investigate the effect of adding nGO on the shear bond strength (SBS) of conventional (CGIC) and resin-modified GIC (RMGIC).

METHODS

Sixty intact molars were mounted and their occlusal surface was cut at a depth of 1 mm below the dentinoenamel junction. 1 wt.% and 2 wt.% of nGO (US Research Nanomaterials, Inc.) were added to CGIC and RMGIC (GC Corporation). The samples were randomly divided into six groups (n = 10), including 1: CGIC,  2: CGIC + 1% GO, 3: CGIC + 2% GO, 4: RMGIC, 5: RMGIC + 1% GO, and 6: RMGIC + 2% GO. Plastic molds were placed on the surface of the dentin pretreated with 10% polyacrylic acid (GC Corporation) and filled with prepared cement according to the manufacturer's instruction. After 24 h of storage in an incubator, the SBS test was done by the universal testing machine. Data were analyzed using two-way analysis of variance and post hoc Tukey tests (p < .05).

RESULTS

In the group of CGIC, mean SBS was significantly lower than all other study groups (p < .001), and groups 5 (RMGIC + 1% GO) and 6 (RMGIC + 2% GO) showed significantly higher values compared to all other study groups (p < .001). However, the difference between groups 2 and 3, as well as the difference between groups 5 and 6, was not significant (p = .999 andp = .994, respectively). RMGI groups had significantly higher SBS than their corresponding CGIC groups.

CONCLUSIONS

The addition of 1% and 2% nGO significantly increased the SBS of CGIC and RMGIC to the dentin, which can be considered as a promising point for wider clinical application of this material.

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.

Comparative evaluation of shear bond strength of three different glass ionomer cement (conventional, zirconium-reinforced and advanced glass hybrid) in primary molars: an in vitro study

PURPOSE

The success of restorative materials is largely dependent on their capacity to adhere to the tooth structure and withstand the various forces present in the oral cavity. So, the aim of present study was to evaluate and compare the shear bond strength (SBS) of Type IX Glass Ionomer Cement (GIC), Zirconomer, and Gold Label Hybrid GIC in primary molars.

METHODS

Thirty primary molars were selected based on inclusion and exclusion criteria. The molars were polished to provide a flat dentin surface after being inserted in auto polymerizing acrylic resin. The samples were randomly divided into three groups, equally and were bonded to GIC. On the dentin surface, restoration cylinders were made using a plastic mould that had an internal diameter and height of 5 mm and 3 mm, respectively. The cement was manipulated according to the manufacturer's directions through the plastic mould. Then, the samples were stored at room temperature for 10 days to mimic oral conditions. The Universal Testing Machine was used to test SBS. One-way ANOVA and the post hoc Tukey test were used to statistically assess the collected data.

RESULTS

A statistically significant difference was found in all three groups (p < 0.01), with Zirconomer demonstrating highest SBS, followed by Type IX GIC and Gold Label Hybrid GIC.

CONCLUSION

The SBS value of Zirconomer was better when compared to Type IX GIC and Gold Label Hybrid GIC.

Finite Element Analysis of the Mechanical Performance of Non-Restorable Crownless Primary Molars Restored with Intracoronal Core-Supported Crowns: A Proposed Treatment Alternative to Extraction for Severe Early Childhood Caries

Early childhood caries (ECC) involve extensive coronal tooth structure loss, and tooth reconstruction remains highly challenging. To fulfill preclinical assessment, the present study investigated the biomechanics of non-restorable crownless primary molars that were restored by stainless steel crowns (SSC) using different composite core build-up materials. Computer-aided design-integrated 3D finite element and modified Goodman fatigue analyses were performed to determine stress distribution, risk of failure, fatigue life and dentine-material interfacial strength for the restored crownless primary molars. A dual-cured resin composite (MultiCore Flow), a light-cured bulk-fill resin composite (Filtek Bulk Fill posterior), a resin-modified glass-ionomer cement (Fuji II LC) and a nano-filled resin-modified glass-ionomer cement (NRMGIC; Ketac N100) were used as core build-up composite materials in the simulated models. The finite element analysis showed that types of core build-up materials affected the maximum von Mises stress only in the core materials (p-value = 0.0339). NRMGIC demonstrated the lowest von Mises stresses and revealed the highest minimum safety factor. The weakest sites were along the central grooves regardless of type of material, and the ratio of shear bond strength to maximum shear stress at the core-dentine interface of the NRMGIC group was lowest among the tested composite cores. However, all groups provided lifetime longevity from the fatigue analysis. In conclusion, core build-up materials differentially influenced the von Mises stress (magnitude and distribution) and the safety factor in crownless primary molars restored with core-supported SSC. However, all materials and the remaining dentine of crownless primary molars provided lifetime longevity. The reconstruction by core-supported SSC, as an alternative to tooth extraction, may successfully restore non-restorable crownless primary molars without unfavorable failures throughout their lifespan. Further clinical studies are required to evaluate the clinical performance and suitability of this proposed method.

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.

Evaluation of Fluoride Release in Chitosan-Modified Glass Ionomer Cements

OBJECTIVE

This study assessed the influence of chitosan nanoparticles on the fluoride-releasing ability of 4 glass ionomer cement (GIC) through an in vitro analysis.

METHODS

Four types of GIC (type II light cure universal restorative, type II universal restorative, GC Fuji VII, and type IX) were modified with nanochitosan particles; 10% chitosan was added to the glass ionomer liquid. Six specimens for each of the 4 groups were created, using expendable Teflon moulds. Discs of each type of GIC (n = 6) were immersed in deionised water at various time intervals. Electrodes selective for fluoride ions were employed to analyse the amount of released fluoride at 1, 7, 14, 21, and 28 days.

RESULTS

Chitosan-modified GICs showed greater fluoride release than conventional GICs at all time points. All samples showed an initial high release of fluoride that tapered off with time. The total amount of fluoride released increased from the 1st day to the 28th day on adding chitosan to all the 4 types of GIC. Amongst those, type IX high-strength posterior extra with chitosan released a considerably higher quantity of fluoride at all time intervals.

CONCLUSIONS

In all the experimental groups, adding chitosan to the glass ionomer liquid had an accelerating effect on its fluoride-releasing property.

An ex vivo evaluation of physico-mechanical and anti-biofilm properties of resin-modified glass ionomer containing ultrasound waves-activated nanoparticles against Streptococcus mutans biofilm around orthodontic bands

BACKGROUND

The present study evaluated the physico-mechanical and antimicrobial properties of ultrasound waves-activated modified-resin glass ionomer containing nanosonosensitizers such as nano-curcumin (n-Cur), nano-emodin (n-Emo), and nano-quercetin (n-Qct) against Streptococcus mutans biofilm on the surface of modified-resin glass ionomer bonded orthodontic bands.

MATERIALS AND METHODS

A total of 50 human molar teeth were used in this study. The shear bond strength (SBS), adhesive remnant index (ARI), setting time, and fluoride release of modified orthodontics cement containing different concentrations of n-Cur, n-Emo, and n-Qct (0, 2, 5, and 10%) were measured. The antimicrobial effectiveness was assessed against S. mutans by the biofilm inhibition test, and the Log₁₀ colony-forming unit (CFU)/mL was evaluated.

RESULTS

SBS and setting time of modified glass ionomer decreased compared with the control group. 5% n-Emo, 2% n-Qct, and 5% n-Cur were the highest concentrations that had an insignificant difference in comparison with Transbond XT (P = 0.647, 0.819, and 0.292, respectively). The groups were not significantly different in terms of ARI score (P > 0.05). The highest and lowest setting time belonged to the control and 5% n-Emo groups, respectively; this difference in setting time was significant (P < 0.05). Ultrasound waves and 0.2% CHX significantly reduced S. mutans biofilms compared with the control group (P < 0.001), and minimum S. mutans colony count was shown in 0.2% CHX and 5% n-Emo groups. The addition of nanosonosensitizers to the glass ionomer did not compromise the fluoride release of the glass ionomer.

CONCLUSION

It could be concluded that resin-modified glass ionomer containing ultrasound waves-activated 5% n-Emo reduces S. mutans biofilm around orthodontic bands with no adverse effect on SBS, ARI, and its application in the clinic.

Shear Bond Strength of Glass Ionomer Cement to Er, Cr:YSGG Laser-irradiated Dentin in Primary Teeth: An In Vitro Study

Background

The clinical success of restorative materials depends upon a good adhesion with the dentinal surface to resist various dislodging forces acting within the oral cavity. Shear bond strength is the resistance to forces that slides restorative material past tooth structure. The Er, Cr:YSGG pulsed laser irradiation may be used to prepare enamel, dentin, cementum, and bone effectively and cleanly without leaving a smear layer.

Aim

To compare the shear bond strength of GIC to dentin treated with conventional cavity conditioning and laser irradiation methods.

Methodology

Thirty samples of noncarious human primary molars which get exfoliated either due to physiologic reasons or extracted due to any therapeutic reasons were collected for the study. Occlusal enamel was removed and teeth were then embedded in self-cured acrylic mold. All the prepared specimens were disinfected with Chloramine T solution and stored in distilled water for 24 hours at room temperature and teeth were randomly divided into the following groups; group 1: conventional cavity conditioning and type IX GIC restoration, group 2: Er, Cr:YSGG conditioning and type IX GIC restoration. Specimens were then subjected to thermocycling and shear bond strength was evaluated using the Lloyd testing machine.

Statistical analysis

One-way ANOVA test followed by Tukey's HSD post hoc analysis was used to compare mean shear bond strength between two study groups. The level of significance [p-value] were set at p < 0.05.

Result

Conditioning the dentin surface with Er, Cr:YSGG laser can increase the shear bond strength of glass ionomer restoration than conventional cavity conditioning.

How to cite this article

Chikkanarasaiah N, P H. Shear Bond Strength of Glass Ionomer Cement to Er, Cr:YSGG Laser-irradiated Dentin in Primary Teeth: An In Vitro Study. Int J Clin Pediatr Dent 2022;15(2):199-203.

A comparative evaluation of microleakage and dentin shear bond strength of three restorative materials

Aim

To evaluate the microleakage and dentin shear bond strength of two glass containing restorative materials, Zirconomer and Cention N, and to compare them with a conventional glass ionomer cement (GIC) (GC Fuji II).

Materials and methods

Zirconomer (Shofu) and GC Fuji II (GC Corp.) are self-curing GICs whereas Cention N (IvoclarVivadent) also offers a self-curing option as well as the option of light-curing using an adhesive. For evaluating microleakage, standardized class V cavities were prepared on the buccal surface of 30 premolars. The cavities were restored with one of the three restorative materials (n = 10) according to manufacturers’ instructions, Cention N being used with an adhesive (Te-EconomBond, IvoclarVivadent) and in the light-curing mode. After restoration and thermocycling, the microleakage assessment was made under a stereomicroscope at 40x magnification following immersing of the teeth in 0.5% methylene blue dye and buccolingual sectioning. For evaluating dentin shear bond strength, the occlusal surface of the 30 premolars was ground flat, and cylinders of the three restorative materials (n = 10) were bonded to the occlusal surface according to manufacturers’ instructions, Cention N being used with an adhesive (Te-EconomBond, IvoclarVivadent) and in the light-curing mode. Following 24-h storage at 100% humidity, the dentin shear bond strength was measured and the fracture mode was determined under a stereomicroscope at 10× magnification. Data were statistically analyzed using Mann–Whitney and Scheffé tests (p = .05).

Results

Cention N displayed significantly less microleakage than did Zirconomer and GC Fuji II at occlusal as well as the gingival margins. Dentin shear bond strength varied significantly between 5.15 and 9.89 MPa with Cention N showing the highest bond strength and GC Fuji II the lowest.

Conclusion

In this in vitro evaluation, Cention N consistently performed better than the conventional GIC (GC Fuji II) as well as Zirconomer.

Comparative Evaluation of Shear Bond Strength of Bioactive Restorative Material, Zirconia Reinforced Glass Ionomer Cement and Conventional Glass Ionomer Cement to the Dentinal Surface of Primary Molars: an in vitro Study

STATEMENT OF THE PROBLEM

The success of dental restorations depends mainly on its ability to bond to dental structures and resist the multitude of forces acting on it within the oral cavity.

PURPOSE

Therefore, the aim of this study was to evaluate the shear bond strength (SBS) of three different glass ionomer based restorative materials.

MATERIALS AND METHOD

In this in vitro analytical study, 30 intact primary molars were sectioned buccolingually to obtain 60 sections. These sections were embedded in auto polymerizing acrylic resin and polished to obtain a flat dentin surface. Restoration cylinders were built on the dentin surface with the help of a Teflon template called bonding jig. Each group (n= 20) was restored as group A with conventional glass ionomer cement (GIC) (GC Fuji Gold Label Type 9), group B with Bioactive restorative material (ACTIVA^TM KIDS BioACTIVE Restorative material), and group C with Zirconia reinforced glass ionomer cement (Zirconomer). Following restoration, SBS testing was performed using Universal Testing Machine. The data obtained were statistically analyzed using One way ANOVA test and post hoc Tukey test (p= 0.05).

RESULTS

The SBS values were significantly greater in the ACTIVA KIDS group as compared to the other two groups (p< 0.05). There was no significant difference in the SBS values between group B and group C (p> 0.05).

CONCLUSION

The SBS of the ACTIVA KIDS to primary teeth dentin was the highest as compared to Zirconomer and conventional GIC. Therefore ACTIVA KIDS may protect primary teeth against recurrent caries and failure of the restoration.

Meta-Analysis of In-Vitro Bonding of Glass-Ionomer Restorative Materials to Primary Teeth

Restoration of primary teeth is among the main clinical applications of glass-ionomer cements (GIC). The aim of the study was to review and summarize existing evidence of in vitro bond strength of glass-ionomer (GI) restoratives to enamel and dentin of primary teeth. A literature search was performed in PubMed/Medline, Scopus, Web of Science, Cochrane, and Google Scholar databases to identify studies published until April 2021. The search strategy was: (“glass”) and (“ionomer”) and (“primary” or “deciduous”) and (“bond” or “tensile” or “shear”). Two researchers independently retrieved articles that reported on the bond strength of GIC to primary dentin and/or enamel. The meta-analysis was performed to compare the bond strength values of conventional (C) GIC and resin-modified (RM) GIC to different substrates. From 831 potentially eligible articles, 30 were selected for the full-text examination, and 7 were included in the analysis. Studies were rated at high (3), medium (3), and low (1) risk of bias. RM-GIC showed higher bond strength to primary enamel and dentin compared to the C-GIC. Meta-analysis of in vitro studies, evaluating bonding properties of GI restoratives to primary teeth, suggests the superior performance of RM-GIC. However, there is a lack of studies that examine the properties of novel GI formulations.

The effects of chitosan addition to glass ionomer cement on microhardness and surface roughness

OBJECTIVE

The aim of this study was to investigate the surface microhardness and roughness properties of a modified glass ionomer cement formed by adding different ratios of Chitosan, when exposed to saliva and acid erosive gastric acid cycle environments.

METHODS

Chitosan was added to conventional glass ionomer liquid at volumes of 5% and 10%. The chitosan-modified glass ionomer was used for the experimental group, and traditional glass ionomer formed the control group. All the groups were separated into two subgroups. One of these subgroups was subjected to a gastric acid erosive cycle. The other subgroup was immersed in artificial saliva. Microhardness, surface roughness with optical profilometer and AFM measurements of all the samples were taken. Qualitative surface topographic evaluations were made using a SEM. The data were analyzed by Kruskal-Wallis and Mann Whitney U-test for pairwise comparisons of the groups at the 0.05 level of significance.

RESULTS

The addition of chitosan to GIC had a positive effect on the microhardness values. The gastric acid erosive cycle application negatively affected the microhardness and surface roughness properties of the sample groups.

CONCLUSION

The chitosan-modified glass ionomer cement samples showed clinically acceptable surface roughness values. Although the results of the addition of the biopolymer, chitosan, to GIC are promising, there is a need for further in-vivo studies.

Comparison of microleakage between different restorative materials to restore marginal gap at crown margin

Background

An occurrence of secondary caries around the indirect restoration margin is reported to remain a leading cause of failures.

Objective

This study aimed to test the interfacial microleakage of conventional glass-ionomer (CGI), resin-modified glass ionomer (RMGI) and Nano-hybrid composite (CR) restorations at a full veneer margin crown.

Methods

Ninety human extracted molar teeth were divided into three groups (n = 30). Each group was subdivided into three subgroups (n = 10) according to the extent of the structural defects; The structural defect in G1 had a depth of 1.5 mm, width and length at 2 mm and 1 mm intrusion within the crown cervical margin. The corresponding structural defect dimension values for G2 were 2, 5, 4 and 2 mm with defects extending onto the root structure. Meanwhile, G3: structural deficiency of 2 mm depth, 3 mm width and 3 mm length and with 1.5 mm extension into the prepared teeth. These structural defects in each subgroup were restored with CGI, RMGI and CR. Artificial carious lesion formation was induced at the cervical finish line with a demineralizing solution. The artificial carious lesions were restored as per the group distribution. Subsequently, teeth samples were prepared and cemented with Nickel-chromium full coverage restorations utilizing glass-ionomer luting cement. Teeth samples were thermocycled, isolated with nail varnish, and immersed in 0.1% methylene blue for 24 h. The teeth samples were sectioned longitudinally, dye penetration was evaluated with a stereomicroscope. The data were analyzed with Kruskal–Wallis and Mann–Whitney U tests.

Results

CGI-G1 recorded the highest micro-leakage score at 1.450; while CR-G3 recorded the least score (0.350). At a cementum-restoration interface, CR-G1 (0.850) documented the lowest micro-leakage; RMGI-G3 had a greater value at 1.700.

Conclusions

The hybrid CR could be effectively used to restore the restoration of a marginal gap around crown margins.

Shear Bond Strength and Film Thickness of a Naturally Antimicrobial Modified Dental Luting Cement

Although several natural plants and mixtures have been known and used over the centuries for their antibacterial activity, few have been thoroughly explored in the field of dentistry. Thus, the aim of this study was to enhance the antimicrobial activity of a conventional glass ionomer cement (GIC) with natural plant extracts. The effect of this alteration on the bond strength and film thickness of glass ionomer cement was evaluated and related to an 0.5% chlorohexidine modified GIC. Olive leaves (Olea europaea), Fig tree (Ficus carica), and the leaves and roots of Miswak (Salvadora persica) were used to prepare an alcoholic extract mixture. The prepared extract mixture after the evaporation of the solvent was used to modify a freeze-dried glass ionomer cement at three different extracts: water mass ratios 1:2, 1:1, and 2:1. An 0.5% chlorhexidine diacetate powder was added to a conventional GIC for the preparation of a positive control group (CHX-GIC) for comparison. The bond strength to dentine was assessed using a material-testing machine at a cross head speed of 0.5 mm/min. Failure mode was analyzed using a stereomicroscope at 12× magnification. The cement film thickness was evaluated in accordance with ISO standard 9917-1. The minimum number of samples in each group was n = 10. Statistical analysis was performed using a Kruskal–Wallis test followed by Dunn’s post hoc test for pairwise comparison. There was a statistically insignificant difference between the median shear bond strength (p = 0.046) of the control group (M = 3.4 MPa), and each of the CHX-GIC (M = 1.7 MPa), and the three plant modified groups of 1:2, 1:1, 2:1 (M = 5.1, 3.2, and 4.3 MPa, respectively). The CHX-GIC group showed statistically significant lower median values compared to the three plant-modified groups. Mixed and cohesive failure modes were predominant among all the tested groups. All the tested groups (p < 0.001) met the ISO standard of having less than 25 µm film thickness, with the 2:1 group (M = 24 µm) being statistically the highest among all the other groups. The plant extracts did not alter either the shear bond strength or the film thickness of the GIC and thus might represent a promising additive to GICs.

Comparison of Shear Bond Strength of Three Types of Glass Ionomer Cements Containing Hydroxyapatite Nanoparticles to Deep and Superficial Dentin

Statement of the Problem

The clinical success of glass ionomer cement (GIC) restorations depends on the strength of its bonding to dentin, yet the bond strength of nanohydroxyapatite (nHAp) added GIC to dentin needs to be investigated.

Purpose

This study aimed to assess if the type of GIC containing nHAp and dentin depth could affect the shear bond strength (SBS).

Materials and Method

In this experimental study, 60 freshly extracted intact third molars were randomly divided into two main groups of flat occlusal dentin with different cuts as superficial (S); just below the dentinoenamel junction (DEJ) and deep (D); 2mm below DEJ. After conditioning with 20% polyacrylic acid, each group were randomly assigned to the tested GIC (n=10) subgroups as (1) Fuji IX Extra+nHAp, (2) Fuji II LC+nHAp and (3) Zirconomer+nHAp. Plastic tubes were placed on the pre-treated surfaces and filled with one of the GIC, then stored in an incubator at 37 oC and 100% humidity for 24hr. The specimens were thermocycled at5/55 oC for 500 cycles and subjected to SBS test using a universal testing machine (1 mm/min). The data analyzed by Mann-Whitney and Kruskal-Wallis test (p< 0.05).

Results

The means of SBS of Fuji II LC+nHAp was significantly higher than Fuji IX+nHAp and Zirconomer+nHAp both in superficial and deep dentin (p< 0.05). The means of SBS of Fuji IX Extra+nHAp and Zirconomer+nHAp subgroups in superficial dentin were higher than deep dentin, this differences was statistically significant (p= 0.0001 and p= 0.009, respectively).

Conclusion

It can conclude that SBS was influenced by type of GIC and depth of dentin.

Shear Bond Strength of Glass Ionomer Cement to Silver Diamine Fluoride-Treated Artificial Dentinal Caries

Purpose: The purpose of this study was to measure the shear bond strength (SBS) of glass ionomer cement (GIC) to artificial carious dentin with and without silver diamine fluoride (SDF) treatment. Methods: Permanent molars were sectioned and demineralized to create artificial carious lesions. In five groups, the demineralization of dentin, application of SDF, use of conditioner, and elapsed time between the placement of SDF and restoration were tested for differences in SBS using an UltraTester machine. Statistical analysis was done using the Kruskal-Wallis test and Tukey-Kramer multiple comparison tests. Results: The highest bond strength was found when GIC was placed on conditioned and demineralized dentin treated with SDF one week earlier. Treatment with SDF and use of conditioner did not statistically affect the SBS of GIC to demineralized dentin. Statistically significant increases in bond strength were found when one week elapsed between SDF application and GIC placement. The lowest bond strength was found with immediate GIC application onto SDF-treated demineralized dentin. Conclusions: These in vitro findings suggest that silver diamine fluoride treatment does not significantly affect the bond strength of glass ionomer cement to dentin lesions, and improved retention is obtained by allowing SDF solution to set for one week prior to GIC placement.

Influence of photobio-modulation with an Er,Cr: YSGG laser on dentin adhesion bonded with bioactive and resin-modified glass ionomer cement

METHODS

One hundred and twenty extracted human molars were allocated in eight groups (n = 15) based on surface conditioning and cement type. Specimens of groups 2 and 6 were conditioned with ECL whereas, groups 3 and 7 were treated with ECL + ethylenediamine tetra acetic acid (EDTA). Specimens in groups 4 and 8 were surface conditioned by ECL + EDTA + Tetric-N-Bond, and groups 1 and 5 were considered as control (non-surface treated). Cement build-ups were performed on the surface-treated dentin with BAC (groups 1-4) and RMGIC (groups 5-8). A universal testing machine was used to measure the SBS and the mode of failure was evaluated using a stereomicroscope. Statistical analysis was performed using an analysis of variance and Tukey's post hoc test, at a significance level of p < 0.001.

RESULTS

The highest SBS values were observed in group 8, ECL + EDTA + Tetric-N-Bond + RMGIC (21.54 ± 3.524 MPa) and the lowest SBS values were displayed by group 1, with no surface treatment and BAC application (11.99 ± 0.821 MPa). The majority of failures were found to be mixed in lased dentin-treated dentin surfaces. BAC when bonded to dentin surfaces conditioned with ECL showed lower SBS in comparison to RMGIC.

CONCLUSION

Conditioning of dentin with ECL and a bonding agent (Tetric-N-bond) improved bond strength scores for BAC and RMGIC. Use of EDTA improved bond strength values when bonded to BAC and RMGIC; however, this improvement was not statistically significant.

The Effect of Incorporation of 0.5 %wt. Silica Nanoparticles on the Micro Shear Bond Strength of a Resin Modified Glass Ionomer Cement

STATEMENT OF THE PROBLEM

The clinical success of glass ionomer restorations depends on the strength of resin-modified glass ionomer (RMGI) cement bonding to dentin and there is limited information available regarding the bond strength of resin modified glass ionomers containing silica nanoparticles to dental structures.

PURPOSE

The aim of this study was to compare the microshear bond strength (µSBS) of RMGI with and without silica (SiO2) nanoparticles to dentin of permanent teeth.

MATERIALS AND METHOD

In this experimental study, the occlusal surfaces of 30 freshly extracted intact third molars were ground to expose the flat dentin and after conditioning with 20% poly acrylic acid, were randomly assigned to two main groups (n=15). The first group was filled with RMGI (Fuji II LC, GC) and the second group was filled with RMGI plus 0.5%wt. silica nanoparticles. Then, each main group was divided into three subgroups, and then stored in an incubator at 37 oC with 100% humidity for 1, 7, and 30 days. The µSBS test was performed using a universal testing machine (1 mm/min). The data were analyzed by t-test, repeated measures ANOVA and Tukey test (p< 0.05).

RESULTS

There were no statistically significant differences between the mean µSBS of the groups with and without nanoparticles along the different storage periods (p> 0.05). There was significant difference in µSBS values among the three different storage periods in all the tested materials (p< 0.05).

CONCLUSION

Incorporation of 0.5 %wt. silica nanoparticles did not compromise the µSBS of Fuji II LC RMGI to dentin.

Effect of a filled adhesive as the desensitizer on bond strength of "Self-Adhesive Cements To" differently severity of fluorosed dentin

The objectives were to evaluate the efficacy of a filled adhesive named Prime & Bond NT (P&B NT) as the dentin desensitizer in occluding fluorosis dentinal tubules and compare the shear bond strength (SBS) of RelyX U200 self-adhesive resin cement (RXU) and RelyX Luting self-adhesive resin-modified glass ionomer cement (RMGIC) before and after P&B NT pretreatment. 176 non-carious fluorosis were classified into four subgroups by the Thylstrup and Fejerskov index (TFI): normal group (TFI = 0), mild group (TFI = 1-3), moderate group (TFI = 4-5), severe group (TFI = 6-9). 160 composite cylinders (4 × 5 mm) were fabricated, then every severity of fluorosed dentin was subjected to four treatments: P&B NT + RXU (n = 40), RXU (n = 40), P&B NT + RMGIC (n = 40), RMGIC (n = 40). The specimens were immersed in water at 37°C for 24 hr first and half of them underwent 5,000 thermocycling before shear bond strength test. A factorial design (factorial 4 × 2 × 2 × 2) was developed to make statistical analysis. Scanning electron microscope (SEM) analysis (n = 16) in cross section and longitudinal section view characterized the occlusion situation of dentinal tubules. P&B NT might occlude dentinal tubules as the dentin desensitizer for normal teeth and mild-moderate fluorosis. P&B NT significantly increased the SBS of RXU (p < .05) but had no statistical significance on the SBS of RMGIC (p > .05). RXU could benefit from P&B NT desensitization to achieve a better quality of adhesion.