Comparing cytocompatibility of two fluoride-containing solutions and two resin-based restorative materials-a pilot study.

Background: Cytocompatibility should always be considered, especially if the surface of treated carious lesions is close to soft tissue or is accidentally exposed to the oral soft tissue by the clinician. Methods: The aim of the present study was to compare the cytocompatibility of two fluoride-containing liquids and two resin-containing restorative materials with buccal mucosa fibroblasts. The fluoride-containing materials were silver diamine fluoride and water-based silver fluoride. Results: The statistical analysis was completed by comparing the positive control growth of the buccal mucosa fibroblasts to the growth of cells exposed to various materials. The one-way ANOVA with Tukey's HSD result was completed. All the assessed materials compared to the control wells for both the 24 and 48 h time intervals indicated a significant cytocompatibility result, except for the test wells with Stela (SDI) at the 24 h time interval. There was no significant difference between the step 2 liquids and the two dental materials in cytocompatibility at the 24 h interval. All four materials indicated no significant differences between the cytocompatibility of any dental materials for 48 h. Conclusion: The cytocompatibility assessment for Riva Star and Riva Star Aqua with the direct method in a full dispensing drop is not viable for step 1 of the fluoride-containing liquids. The use of Stela Light Cure is a suitable material that will be in contact with buccal mucosa as it showed potential for increased cytocompatibility compared to Riva Light Cure. Riva Star Aqua is more cytocompatible than Riva Star.

Comparison of Three Different Orthodontic Adhesives Bonded to Metallic and Ceramic Brackets: SEM and SEM/EDX Analysis (In Vitro Study).

Objectives: To compare three different orthodontic adhesives (Transbond XT Light Cure Adhesive, Heliosit Orthodontic, Fuji Ortho LC) bonded to two types of orthodontic brackets: ceramic brackets (Fascination Roth 0.22) and metallic brackets (Topic Roth 0.22, Dentaurum). Materials and methods: The study was performed on 18 human teeth (6 for each adhesive). The prepared teeth were divided into three groups according to the examination time. Subsequently, they were observed after 1, 2 and 3 weeks following bonding. After the experimental procedure, the teeth samples were cut in half along the longitudinal axis in the vestibulo-oral direction, fixed with conductive carbon cement, placed in a high-vacuum evaporator and then coated with carbon. One half of each sample was observed under a Field-emission gun scanning electron microscope (FEG-SEM Hitachi SU 8030, Japan), while on the second half of the samples qualitative (X-ray line-scans) and semi-quantitative point X-ray energy dispersive analyses (EDX) were performed with Thermo Noran (USA) NSS System 7, equipped with Ultra Dry detector (30 mm2 window). Results: Transbond XT had an ideal bond with the enamel and the bracket base, with rare presence of microgaps and cracks in the enamel. Heliosit Orthodontic demonstrated a better bond relationship with the bracket base than the enamel, whereas in the latter the presence of microgaps in the bond was observed. The microphotographs of Fuji Ortho LC demonstrated many cracks inside the adhesive, and some of them continued to move forward into the enamel surface. Therefore, an impression of a very solid bond relationship with the enamel exists, with cracks being present in the enamel surface and never at the enamel-adhesive interface. Microgaps also appeared at the bracket-adhesive interface. Conclusion: Transbond XT is a highly filled composite resin and is an ideal orthodontic adhesive in each aspect examined, with an ideal enamel-adhesive and bracket-adhesive interface. Heliosit Orthodontic provides better bracket-adhesive interface compared to the enamel. Fuji Ortho LC as a solid resin-modified GIC provides a better enamel-adhesive interface, compared to the bracket base.

A scoping review of the influence of clinical contaminants on bond strength in direct adhesive restorative procedures.

OBJECTIVE: Clinical contamination during direct adhesive restorative procedures can affect various adhesive interfaces differently and contribute to bulk failure of the restorations. This review aims to summarise the current knowledge on the influence of a variety of clinical contaminants on the bond strength at various adhesive interfaces during adhesive restorative procedures and identify gaps in the literature for future research. DATA AND SOURCES: An electronic database search was performed in PubMed and EMBASE to identify articles that investigated the influence of contaminants on direct restorative bonding procedures. A data-charting form was developed by two researchers to capture the key characteristics of each eligible study. STUDY SELECTION: The initial search yielded 1,428 articles. Fifty-seven articles published between 1 Jan 2007 and 25 Oct 2023 were included in the final review. Thirty-three of the articles examined the influence of saliva contamination, twelve articles examined the influence of blood contamination, and twenty-five articles examined the influence of other contaminants. CONCLUSION: Saliva contamination exerted less influence on the decrease in bond strength when self-etch systems were used, compared to when etch-and-rinse systems were used. Blood contamination adversely affected the bond strength at the interface between resin composite and dentine, and resin composite and resin-modified glass ionomer cement. Treating contaminated surfaces with water spray for 10-30 s followed by air drying could be effective in recovering bond strength following saliva and blood contamination. CLINICAL SIGNIFICANCE: This scoping review provides a valuable overview of the range of potential clinical contaminants that can influence the bond strength between different interfaces in direct adhesive restorative procedures. Additionally, it identifies potential decontamination protocols that can be followed to restore and enhance bond strength.

Cell Viability Assessment and Ion Release Profiles of GICs Modified with TiO2- and Mg-Doped Hydroxyapatite Nanoparticles.

OBJECTIVES: To assess and compare the cell viability and ion release profiles of two conventional glass ionomer cements (GICs), Fuji IX and Ketac Molar EasyMix, modified with TiO2 and Mg-doped-HAp nanoparticles (NPs). METHODS: TiO2 NPs, synthesized via a sol-gel method, and Mg-doped hydroxyapatite, synthesized via a hydrothermal process, were incorporated into GICs at a concentration of 5 wt.%. The biocompatibility of prepared materials was assessed by evaluating their effects on the viability of dental pulp stem cells (DPSCs), together with monitoring ion release profiles. Statistical analysis was performed using One-way analysis of variance, with significance level p < 0.05. RESULTS: The addition of NPs did not significantly affect the biocompatibility of GICs, as evidenced by comparable decreased levels in cell viability to their original formulations. Distinct variations in cell viability were observed among Fuji IX and Ketac Molar, including their respective modifications. FUJI IX and its modification with TiO2 exhibited moderate decrease in cell viability, while other groups exhibited severe negative effects. While slight differences in ion release profiles were observed among the groups, significant variations compared to original cements were not achieved. Fluoride release exhibited an initial "burst release" within the initial 24 hours in all samples, stabilizing over subsequent days. CONCLUSIONS: The addition of NPs did not compromise biocompatibility, nor anticariogenic potential of tested GICs. However, observed differences among FUJI IX and Ketac Molar, including their respective modifications, as well as induced low viability of DPSC by all tested groups, suggest the need for careful consideration of cement composition in their biological assessments. CLINICAL SIGNIFICANCE: The findings contribute to understanding the complex interaction between NPs and GIC matrices. However, the results should be interpreted recognizing the inherent limitations associated with in vitro studies. Further research avenues could explore long-term effects, in vivo performance, and potential clinical applications.

Compressive strength and fluoride release profile of a glass ionomer cement reinforced with silver-hydroxyapatite-silica hybrid nanoparticles: An in vitro study.

OBJECTIVES: This study aimed to prepare a glass ionomer (GI) cement reinforced with silver-hydroxyapatite-silica (Ag/HA/Si) hybrid nanoparticles and assess its compressive strength and fluoride release profile. MATERIAL AND METHODS: In this in vitro, experimental study, 60 cylindrical specimens were fabricated with 4mm diameter and 6mm height in 6 groups (n=10) using BracePaste composite, GC Fuji II LC pure RMGI, and RMGI reinforced with 0.1wt%, 0.5wt%, 1wt%, and 2wt% Ag/HA/Si hybrid nanoparticles. The specimens were subjected to compressive force in a universal testing machine to measure their compressive strength (MPa). To assess their fluoride release profile, discs with 3mm diameter and 2mm thickness were fabricated from Fuji II LC pure resin-modified glass ionomer (RMGI), and RMGI with 0.1wt%, 0.5wt%, 1wt%, and 2wt% hybrid nanoparticles, and the concentration of released fluoride was measured by a digital ion-selective electrode. Data were analysed by ANOVA and Scheffe test (alpha=0.05). RESULTS: The compressive strength was 114.14MPa for BracePaste composite, and 97.14, 97.84, 100.65, 109.5, and 89.33MPa for GI groups with 0%, 0.1%, 0.5%, 1% and 2% hybrid nanoparticles, respectively, with no significant difference among them (P=0.665). Addition of 1% (0.21±0.07µg/mL, P=0.029) and 2% (0.45±0.22µg/mL, P=0.000) hybrid nanoparticles to RMGI significantly increased the amount of released fluoride, compared with the control group (0.09±0.03µg/mL). CONCLUSIONS: Addition of Ag/HA/Si hybrid nanoparticles to RMGI in the tested concentrations had no significant effect on its compressive strength but addition of 1wt% and 2wt% concentrations of Ag/HA/Si hybrid nanoparticles increased its fluoride release potential.

In Vitro Analysis of Outcome Differences Between Repairing and Replacing Broken Dental Restorations.

Objective In light of several advancements and considerations in endodontic dentistry, there still remains a need to comprehensively evaluate the outcome disparities between repairing and replacing broken dental restorations. This study aims to compare the effectiveness of repairing dental restorations versus replacing them, focusing on how each method affects the structural strength and longevity of the restorations. Methods The study included 60 freshly removed human maxillary premolars. Initial processing involved rigorous washing, descaling, and polishing of the teeth. To ensure preservation, the specimens were stored in sterile, distilled water. To occlude the root canals, a self-hardening composite resin was used, and the roots were coated with two coats of clear nail polish to prevent moisture penetration. A 245 carbide bur attached to a high-speed dental handpiece with air and water spray cooling produced standardized Class II cavities on the occluso-proximal surfaces. Each cavity had a buccolingual breadth of 2 mm, an occluso-cervical length of 4 mm, and a gingival boundary that was 1 mm coronal to the cement-enamel junction. Following this preparation, the teeth were randomly separated into three groups (Group A, Group B, and Group C), each containing 20 teeth. Results Our analysis showed that teeth with entirely replaced restorations had a higher average fracture resistance than those with repaired restorations. However, the difference in fracture resistance between the repair and replacement groups for each type of material was not statistically significant. Conclusion Based on the findings, repairing a dental restoration can be a conservative and less invasive alternative to a full replacement without a significant compromise in the restoration's ability to withstand fracture. Therefore, dental professionals might consider full restoration as a viable option, taking into account the need to preserve dental tissue as well as the restoration's durability and structural integrity.

A Comparative In Vitro Analysis of Antimicrobial Effectiveness and Compressive Strength of Ginger and Clove-Modified Glass Ionomer Cement.

Background Glass ionomer cement (GIC) is widely recognized for its self-adhesive characteristics and biocompatibility, making it commonly used as a restorative material. However, challenges related to limited antibacterial effectiveness and relatively low mechanical properties have hindered its widespread clinical use. Clove and ginger are recognized for their potent antimicrobial activity against numerous pathogenic microorganisms. The present study aims to enhance the clinical applicability of GIC by modifying it with clove and ginger extract. Aim The objective of the study is to assess the antimicrobial effectiveness and compressive strength of GIC modified with ginger and clove extract. Materials and methods Ginger and clove extracts were prepared and incorporated into conventional GIC at three concentrations for each, creating ginger-modified GIC groups (Group A, Group B, and Group C) and clove-modified GIC groups (Group D, Group E, and Group F), with Group G as the control (conventional GIC without modification). The antimicrobial assessment was conducted on disc-shaped GIC specimens (3.0 mm height x 6.0 mm diameter) prepared using molds. Bacterial strains were used to evaluate antimicrobial properties, with minimum inhibitory concentration (MIC) assays conducted at intervals of one to four hours for both modified and unmodified groups. Compressive strength specimens were prepared using cylindrical molds (6.0 mm height × 4.0 mm diameter), according to the ISO (International Organization for Standardization) guidelines. The evaluation was conducted using a Zwick universal testing machine (ElectroPuls® E3000, Instron, Bangalore, India), with the highest force at the point of specimen fracture recorded to determine compressive strength. Statistical analysis was conducted utilizing a one-way analysis of variance (ANOVA) alongside Tukey's post hoc test, with a significance threshold set at p < 0.01. Results The antimicrobial effectiveness of clove and ginger-modified GIC was assessed through a MIC assay, revealing a statistically significant improvement in antimicrobial potency against Streptococcus mutans and Lactobacillus within the modified groups compared to the control group (p < 0.01). Increased extract concentration correlated with enhanced antimicrobial activity. Clove-modified GIC exhibited superior antimicrobial efficacy compared to ginger extract. Compressive strength was higher in clove-modified GIC groups (p < 0.01), with Group F showing a maximum value of 175.88 MPa, while other modified groups demonstrated similar results to the control, with a value of 166.81 MPa (p > 0.01). Conclusion The study concludes that both clove-modified GIC and ginger-modified GIC exhibited antimicrobial activity against Streptococcus mutans and Lactobacillus species. The antimicrobial activity was notably higher in clove-modified GIC compared to ginger-modified GIC. Additionally, the compressive strength of clove-modified GIC surpassed all other groups. Thus, clove-modified GIC emerges as a promising restorative material for addressing recurrent caries. Future investigation is necessary to assess the long-term durability of the material.

Efficacy of Glass Ionomer Cement as Pit and Fissure Sealant in Permanent First Molars.

Background/Objectives Pit and fissure caries constitute a predominant portion, approximately 90% in permanent posterior teeth and 44% in primary teeth among children and adolescents. Among various preventive modalities, pit and fissure sealants play a pivotal role in safeguarding these vulnerable areas. Categorized by materials such as glass ionomer, composites, and polyacid-modified glass ionomers, these sealants offer effective protection. This study aims to evaluate the efficacy of glass ionomer-based pit and fissure sealants in terms of retention rate at 12-month post-procedure period in permanent first molars. Methodology This study was conducted at the Department of Operative Dentistry, Nishtar Institute of Dentistry, Multan, Pakistan. Fifty-six children, aged 7 to 12 years, presenting with pit and fissure caries in permanent first molar teeth were enrolled. Glass ionomer sealant was meticulously applied to the affected pits and fissures. The efficacy was assessed after 12 months based on predefined criteria. Results The age of participants ranged from 7 to 12 years, with a mean age of 9.24 ± 1.38 years. Among the 56 patients, 23 (41.2%) were male and 33 (58.8%) were female. Sealant retention was noted in 31 (55.35%) patients, while 25 (44.65%) experienced sealant loss. In the 7 to 9-year age group, 19 demonstrated complete sealant retention, whereas in the 10 to 12-year age group, 12 exhibited complete retention. Concerning gender distribution, 17 males and 14 females exhibited complete sealant retention. Conclusion Glass ionomer-based sealants demonstrate excellent properties for pit and fissure sealing owing to their low technique sensitivity, cost-effectiveness, and favorable retention rates. Therefore, they represent an optimal choice for this preventive dental procedure.

Comparing modified USPHS and FDI criteria for the assessment of glass ionomer restorations in primary molars utilising clinical and photographic evaluation.

PURPOSE: To compare the applicability of modified US Public Health Service (USPHS) and FDI criteria for evaluating glass ionomer cement (GIC) restorations in primary posterior teeth through digital image analysis. METHODS: This comparative analytic study was conducted at the Children's Dental Clinic RSKGM FKG UI, involving 40 GIC restorations on lower first primary molars in children aged 4-9 years. After cleaning, the restorations were assessed clinically using modified USPHS and FDI criteria before taking digital images, then the collected images were re-evaluated using both sets of criteria, and the clinical assessment results were compared to the digital image assessment results. RESULTS: Statistical analysis revealed significant differences between the clinical evaluation of GIC restorations in primary teeth and their corresponding digital photographs when using the modified USPHS criteria, and although the use of FDI criteria yielded different results, these differences were not statistically significant. CONCLUSION: The assessment of GIC restorations through digital images aligns more closely with clinical assessments using the FDI criteria compared to the modified USPHS criteria.

Performance evaluation of carbon quantum dots impregnated glass ionomer cement to avoid peri-implant disease.

Dental cement residues exacerbate peri-implant tissue irritation and peri-implantitis. The present study aims to evaluate the cytotoxicity, physiochemical, optical, and rheological properties of Carbon Quantum Dots (CQDs) impregnated Glass Ionomer Cement (GIC). Surface passivated fluorescent CQDs were synthesized using citric acid via thermal decomposition and blended with GIC. Characterization studies and rheological measurements were made to evaluate their performance. 3D-printed dental implant models cemented with GIC and GIC-CQD were compared to analyze excess cement residues. MTT assay was performed with human Dental Pulp Stem Cells (hDPSCs) and statistically analyzed using ANOVA and Tukey's test. CQDs with a particle dimension of ~2 nm were synthesized. The amorphous property of GIC-CQD was confirmed through XRD. The fluorescence properties of GIC-CQD showed three times higher emission intensity than conventional GIC. GIC-CQD attained maturation with a setting time extended by 64 seconds than GIC. Cement residue of size 2 mm was detected with a UV light excitation at a distance between 5 to 10 cm. Biocompatibility at 0.125 mg/ml dilution concentrations of GIC-CQD showed viability greater than 80% to hDPSCs. For the first time, we report that CQDs-impregnated GIC is a unique and cost-effective strategy for in-situ detection of excess cement rapidly using a hand-held device. A novel in-situ rapid detection method enables the dentist to identify residual cement of size less than 2 mm during the implantation. Therefore, GIC-CQD would replace conventional GIC and help in the prevention of peri-implant diseases.

Antimicrobial properties of glass-ionomer cement incorporated with nano-hydroxyapatite against mutans streptococci and lactobacilli under orthodontic bands: An in vivo split-mouth study.

Background: Fixed orthodontic appliances enhance dental plaque accumulation. Glass ionomer (GI) is among the most popular orthodontic cement. It possesses antibacterial properties; however, its antibacterial activity may not be sufficient for caries prevention. Although evidence shows that the addition of 8wt% nano-hydroxyapatite (nHA) may enhance the antibacterial properties of GI, no clinical study has been conducted in this respect. Thus, this study aimed to assess the subgingival accumulation of Streptococcus mutans (S. mutans) and Lactobacillus acidophilus (L. acidophilus) around orthodontic bands cemented with conventional GI and GI reinforced with 8wt% nHA. Materials and Methods: This split-mouth clinical trial was conducted on 20 patients requiring a lingual arch. The patients were randomly assigned to two groups. In group 1, the right molar band was cemented with pure Fuji I (GC), and the left was cemented with Fuji I containing 8wt% nHA. In group 2, the right molar band was cemented with Fuji I containing 8wt% nHA, and the left was cemented with Fuji I. After 3 months, subgingival sampling was performed by sterile paper points. S. mutans and L. acidophilus were cultured on MSB and MRS agar, and colonies were counted by a colony counter. Data were analyzed by independent samples t-test using SPSS 25 at a 0.05 level of significance. Results: The mean counts of S. mutans, aerobic and anaerobic lactobacilli, and total bacterial around orthodontic bands cemented with Fuji I containing 8wt% nHA were significantly lower than those around orthodontic bands cemented with pure Fuji I (P < 0.05). Conclusion: The addition of 8wt% nHA to GI cement can enhance its antibacterial properties for the cementation of orthodontic bands, decrease the accumulation of cariogenic bacteria, and probably decrease the incidence of caries in orthodontic patients.

Minimal intervention dentistry: What is its clinical application and effectiveness in different continents? - A scoping review.

The aim of minimal intervention dentistry (MID) is to maximize the preservation of dental tissues through the use of modern and effective techniques and procedures. The central objective of MID is to increase the functional life of dental elements and, consequently, the quality of life of the population. The present study aimed to analyze and map the diffusion and clinical application of MID in different continents around the world. To perform this scoping review, the PRISMA checklist was used, adopting the following: population - dentists; concept - effectiveness of MID; and context - continents. The following databases were used: PubMed, European Archives of Paediatric Dentistry, Scientific Electronic Library, Latin Literature American and Caribbean Association in Health Sciences, and SCOPUS. The following keywords were used in the searches: "pediatric dentistry," "atraumatic restorative treatment," "dental caries," "child health," and "glass ionomer cements" using "and" and "or" combined with "minimal intervention dentistry." Studies published before 2010 as well as theses, dissertations, opinion articles, editorials, and guidelines, were excluded from the study. A total of 160 articles were obtained, and 17 articles were screened and selected for full reading. The analysis of the studies reveals the disparity in the use of minimal intervention techniques among continents due to a lack of knowledge of these techniques or lack of confidence in changing professional approaches, thus emphasizing the need for the dissemination and teaching of MID.

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.

Adhesion of glass ionomer cements to primary dentin using a universal adhesive.

BACKGROUND: Glass ionomers are widely used for restoring carious primary teeth. However, their ability to bond to primary dentin is considered a challenge in pediatric dentistry. OBJECTIVES: The study aimed to evaluate the microshear bond strength (µSBS) of a resin-modified glass ionomer (RMGI) and a high-viscosity glass ionomer cement (Hv-GIC) to primary dentin using a universal adhesive. MATERIAL AND METHODS: Thirty human primary maxillary canines were cut in half and prepared for the µSBS test. The specimens (N = 60) were assigned to 6 groups. Three groups were defined for RMGI (FUJI II LC) and 3 groups for Hv-GIC (EQUIA Forte): with an immediately curing adhesive (G-Premio); with a delayed curing adhesive; and without an adhesive (control group). After preparing the dentin surfaces, the glass ionomers were bonded using Tygon® tubes with an internal diameter of 0.7 mm. The µSBS test was performed, and the data was analyzed using two-way analysis of variance (ANOVA) followed by Tukey's post hoc test. Additionally, the failure modes were determined using a stereomicroscope. Six specimens, one for each study group, were prepared for scanning electron microscopy (SEM) analysis to observe the glass ionomer-dentin interface. RESULTS: The type of glass ionomer did not have a significant effect on the µSBS (p = 0.305). Groups that received universal adhesive application prior to glass ionomer exhibited a significantly higher µSBS (p < 0.0001). However, there was no significant difference between the immediately curing and delayed curing groups (p = 0.157). The predominant failure mode was mixed failure. CONCLUSIONS: Higher bond strength of glass ionomers to primary teeth can be achieved by using universal adhesives, which, in addition to the proven benefits of glass ionomers, can improve their clinical success.

Mechanical Properties and Ion Release from Fibre-Reinforced Glass Ionomer Cement.

The aim of this study was to compare the mechanical properties and ion release from a commercially available resin-modified glass ionomer cement to a formulation reinforced by the addition of short glass fibres at various percentages. Methods: Three experimental groups were prepared by adding a mass ratio of 10%, 15% and 20% of short glass fibres to the powder portion of the cement from a capsule (GC Fuji II LC), while the control group contained no fibres. Microhardness (n = 12), fracture toughness, and flexural, compressive and diametral tensile strength (n = 8) were evaluated. To study ion release, readings were obtained utilising fluoro-selective and calcium-selective electrodes after 24 h, 7 days and 30 days (n = 12). The spatial distribution of fibres within the material was evaluated through scanning electron microscopy. The data were analysed using one-way ANOVA with a Bonferroni adjustment. Results: The findings suggest that elevating fibre weight ratios to 20 wt% results in improved mechanical properties (p < 0.05) in microhardness, flexural strength, diametral tensile strength and fracture toughness. In terms of ion release, a statistically significant difference (p < 0.001) was observed between the groups at the conclusion of 24 h and 7 days, when the fluoride release was much higher in the control group. However, after 30 days, no significant distinction among the groups was identified (p > 0.05). Regarding calcium release, no statistically significant differences were observed among the groups at any of the evaluated time points (p > 0.05). SEM showed the fibres were homogeneously incorporated into the cement in all experimental groups. Conclusions: Resin-modified glass ionomer enhanced with short glass fibres at a weight loading of 20% showcased the most favourable mechanical properties while concurrently maintaining the ability to release fluoride and calcium after a 30-day period.

The Impact of Nano- and Micro-Silica on the Setting Time and Microhardness of Conventional Glass-Ionomer Cements.

The objective of this study was to investigate the effect of the incorporation of 2, 4 or 6 wt% of amorphous nano- or micro-silica (Aerosil® OX 50 or Aeroperl® 300 Pharma (Evonik Operations GmbH, Essen, Germany), respectively) on the net setting time and microhardness of Ketac™ Molar (3M ESPE, St. Paul, MN, USA) and Fuji IX GP® (GC Corporation, Tokyo, Japan) glass-ionomer cements (GICs) (viz. KM and FIX, respectively). Both silica particles were found to cause a non-linear, dose-dependent reduction in setting time that was within the clinically acceptable limits specified in the relevant international standard (ISO 9917-1:2007). The microhardness of KM was statistically unaffected by blending with 2 or 4 wt% nano-silica at all times, whereas 6 wt% addition decreased and increased the surface hardness at 1 and 21 days, respectively. The incorporation of 4 or 6 wt% nano-silica significantly improved the microhardness of FIX at 1, 14 and 21 days, with no change in this property noted for 2 wt% addition. Micro-silica also tended to enhance the microhardness of FIX, at all concentrations and times, to an extent that became statistically significant for all dosages at 21 days. Conversely, 4 and 6 wt% additions of micro-silica markedly decreased the initial 1-day microhardness of KM, and the 21-day sample blended at 4 wt% was the only specimen that demonstrated a significant increase in this property. Scanning electron microscopy indicated that the nano- and micro-silica particles were well distributed throughout the composite structures of both GICs with no evidence of aggregation or zoning. The specific mechanisms of the interaction of inorganic nanoparticles with the constituents of GICs require further understanding, and a lack of international standardization of the determination of microhardness is problematic in this respect.

Comparing Zirconium Crown Marginal Adaptation in Preparations with Two Different Occlusal Reductions.

This study aimed to assess and contrast the effects on the vertical marginal fit of full contour CAD/CAM-generated monolithic zirconia crowns at pre- and post-cementation levels with various occlusal reduction schemes (planar and flat) and cements. Forty sound human maxillary first premolars were sampled for this study. The samples were divided into two main groups with twenty samples in each group according to the occlusal reduction scheme as follows: Group A included a chamfer finishing line design with a planar occlusal reduction scheme and Group B included a chamfer finishing line design with a flat occlusal reduction scheme. Each group was sampled into two subgroups (n = 10) based on the type of cement as follows: resin-modified glass ionomer cement (Fuji Plus) for subgroups A1 and B1, and a universal adhesive system (Duo Estecem II) for subgroups A2 and B2. Marginal gaps were tested in four indentations using a Dino light stereomicroscope (230×). Paired T-tests and Student's t-tests were used to analyze the data. Before cementation, subgroup A1 scored the lowest mean of vertical marginal gap values, while subgroup B2 scored the highest mean; following cementation, subgroup A1 scored the lowest mean of vertical marginal gap values, and subgroup B2 scored the highest mean of vertical marginal gap values. A chamfer finishing line design with a planar occlusal reduction scheme could be a preferable occlusal reduction scheme.

Comparative Evaluation of Shear Bond Strength of Resin-modified Glass Ionomer Cement with ProRoot MTA and MTA Angelus.

AIM: The aim of the present study was to evaluate the shear bond strength of resin-modified glass ionomer cement with two different types of mineral trioxide aggregate at different time intervals. MATERIALS AND METHODS: A total of 80 cylindrical blocks were prepared using a self-cure acrylic resin with a central cavity of 4 mm internal diameter and 2 mm height. The prepared samples were randomly divided into two groups (n = 40 each) according to the type of MTA cements used (ProRoot MTA and MTA Angelus). Two groups were further sub-divided into four sub-groups of 10 samples each according to the different time intervals. ProRoot MTA and MTA Angelus were placed in the prepared cavity and a wet cotton pellet was placed over the filled cavity. A hollow plastic tube was placed over the MTA surface and resin-modified glass ionomer cement (RMGIC) was placed into the hollow plastic tube and light-cured (Spectrum 800, Dentsply Caulk Milford, DE, USA) according to the time intervals decided. After light curing the plastic tubes were removed carefully and the specimens were stored at 37°C and 100% humidity for 24 hours to encourage setting of MTA. The specimens were mounted in a universal testing machine (ADMET) and a crosshead speed of 0.5 mm/min was applied to each specimen by using a knife-edge blade until the bond between the MTA and RMGIC failed. The data were statistically analyzed using ANOVA, post hoc Tukey's t-test and Fisher's t-test and p-value ≤ 0.5 was considered significant. RESULTS: For both ProRoot MTA and MTA Angelus there was no statistically significant difference between 45 minutes and 24 hours (p-value ≥ 0.8). For ProRoot MTA, shear bond strength value at 10 minutes were significantly lower than 45 minutes and 24 hours group. However, for MTA Angelus, shear bond strength value at 10 minute was not significantly different from 45 minutes group (p-value ≥ 0.3). For both ProRoot MTA and MTA Angelus shear bond strength value at 0 minute were the least and were significantly lower than 10 minutes, 45 minutes, and 24 hours, respectively (p-value ≥ 0.000). CONCLUSION: Resin-modified glass ionomer cement can be layered over MTA Angelus after it is allowed to set for 10 minutes. However, ProRoot MTA should be allowed to set for at least 45 minutes before the placement of RMGIC to achieve better shear bond strength. CLINICAL SIGNIFICANCE: Due to the variety of types of mineral trioxide aggregate cements available in dentistry, it is justifiable to emphasize on different time intervals as it may affect the shear bond strength of restorative cements. Such information is pivotal for the clinicians while using mineral aggregate-based cements that receive forces from the condensation of restorative materials or occlusion, as the compressive strength may be affected due to different time intervals. How to cite this article: Tyagi N, Chaman C, Anand S, et al. Comparative Evaluation of Shear Bond Strength of Resin-modified Glass Ionomer Cement with ProRoot MTA and MTA Angelus. J Contemp Dent Pract 2024;25(1):35-40.

Novel microbial synthesis of titania nanoparticles using probiotic Bacillus coagulans and its role in enhancing the microhardness of glass ionomer restorative materials.

Dental caries is a commonly occurring non-communicable disease throughout the world that might compromise the quality of any individual's life. Glass ionomer cements (GIC) are the most acceptable restorative materials due to their ease of manipulation, minimal tooth loss and least invasive strategy; however, they lack mechanical stability that has become a point of concern. Nanoparticles (NPs) are an outstanding option for modifying and enhancing the properties of dental materials. The focus of this study was to prepare novel, biocompatible titania dioxide (TiO2) NPs as a dental-restorative material using an efficient probiotic Bacillus coagulans. The prepared NPs were incorporated into glass ionomer restorative material at varying concentrations and investigated for cell viability percentage, microhardness and surface morphology. Results indicated that pure 100% anatase phase TiO2 NPs with particle size of 21.84 nm arranged in smooth, spherical agglomerates and clusters forms. These NPs depicted cell viability > 90%, thus confirming their non-cytotoxic behavior. GIC restorative materials reinforced by 5% titania (TiO2) NPs demonstrated the highest microhardness in comparison to the control group and other experimental groups of the study. Surface morphology analysis revealed a reduction in cracks in this novel dental-restorative material supporting its compatible biological nature with better hardness strength and negligible crack propagation. Overall, these results indicated that TiO2 NPs produced using a biological approach could be easily used as restorative materials in dental applications.

Quantitative determination and antibacterial properties of TiO2 nanoparticle-doped glass ionomer cement: an in vitro study.

Purpose: The aim of the present study is to determine the amount of titanium ions released into the artificial salivary medium by modified glass ionomer cement (GIC) doped with 3% and 5% (w/w) titanium dioxide nanoparticles (TiO2-NPs), and to evaluate their antibacterial properties. Materials and methods: 120 cylindrical discs with a diameter of 4 mm and a height of 6 mm were made with 3% and 5% w/w modified GIC containing TiO2 NPs, divided into two groups of 60, and immersed in a chemically synthesized salivary medium. The samples were quantified over four-time periods: 24 hours, two months, four months, and six months, using inductively coupled plasma mass spectroscopy (ICP-MS), antibacterial properties were evaluated by means of colony forming count (CFU) method. Results: The amount of titanium ions released from the discs that received 3%(w/w) TiO2 was highest in the first two months, with no significant release at successive intervals. Also, the second group, which included 5% (w/w) TiO2, saw a considerable ion release at every interval, with the second month seeing the maximum release. The levels in the 5% (w/w) group were consistently higher when the two concentrations were compared at each of the four time points, indicating a considerable increase in titanium release and antibacterial property with a concentration increase from 3% to 5%. Conclusion: 3% and 5% (w/w) concentrations may be considered safe and exhibit significant antimicrobial effect, titanium ions were discharged at higher rates in 5% (w/w) modified GIC containing TiO2-NPs than in 3% (w/w) modified GIC containing TiO2-NPs.