Resin-modified Glass Ionomer Cement Groups Research Articles

Antibacterial, cytotoxic and mechanical properties of a orthodontic cement with phosphate nano-sized and phosphorylated chitosan: An in vitro study

ObjectivesEvaluate, in vitro, the effect of incorporating nano-sized sodium trimetaphosphate (TMPnano) and phosphorylated chitosan (Chi-Ph) into resin-modified glass ionomer cement (RMGIC) used for orthodontic bracket cementation, on mechanical, fluoride release, antimicrobial and cytotoxic properties. MethodsRMGIC was combined with Chi-Ph (0.25%/0.5%) and/or TMPnano (14%). The diametral compressive/tensile strength (DCS/TS), surface hardness (SH) and degree of conversion (%DC) were determined. For fluoride (F) release, samples were immersed in des/remineralizing solutions. Antimicrobial/antibiofilm activity was evaluated by the agar diffusion test and biofilm metabolism (XTT). Cytotoxicity in fibroblasts was assessed with the resazurin method. ResultsAfter 24 h, the RMGIC-14%TMPnano group showed a lower TS value (p < 0.001); after 7 days the RMGIC-14%TMPnano-0.25%Chi-Ph group showed the highest value (p < 0.001). For DCS, the RMGIC group (24 h) showed the highest value (p < 0.001); after 7 days, the highest value was observed for the RMGIC-14%TMPnano-0.25%Chi-Ph (p < 0.001). RMGIC-14%TMPnano, RMGIC-14%TMPnano-0.25%Chi-Ph, RMGIC-14%TMPnano-0.5%Chi-Ph showed higher and similar release of F (p > 0.001). In the SH, the RMGIC-0.25%Chi-Ph; RMGIC-0.5%Chi-Ph; RMGIC-14%TMPnano-0.5%Chi-Ph groups showed similar results after 7 days (p > 0.001). The RMGIC-14%TMPnano-0.25%Chi-Ph group showed a better effect on microbial/antibiofilm growth, and the highest efficacy on cell viability (p < 0.001). After 72 h, only the RMGIC-14%TMPnano-0.25%Chi-Ph group showed cell viability (p < 0.001). ConclusionThe RMGIC-14%TMPnano-0.25%Chi-Ph did not alter the physical-mechanical properties, was not toxic to fibroblasts and reduced the viability and metabolism of S. mutans. Clinical relevanceThe addition of phosphorylated chitosan and organic phosphate to RMGIC could provide an antibiofilm and remineralizing effect on the tooth enamel of orthodontic patients, who are prone to a high cariogenic challenge due to fluctuations in oral pH and progression of carious lesions.

Tensile bond strength between paediatric prefabricated zirconia crowns and primary maxillary incisors when using various types of luting cements: an in vitro study.

There is limited evidence regarding the most appropriate type of luting cement for paediatric prefabricated zirconia crowns (PZCs) in primary maxillary incisors. The retention of PZCs is dependent on the bond strength of luting cement between PZCs and primary maxillary incisors. The aim of this study was to evaluate the tensile bond strengths between PZCs and primary maxillary incisors with different types of luting cements. Thirty freshly extracted human primary maxillary incisors were prepared and randomly divided into three groups corresponding to three luting cements: bioactive cement, resin cement, and resin-modified glass ionomer cement (RMGIC), and then restored with PZCs. Tensile bond strengths were evaluated by a universal testing machine. The results were analysed using one-way ANOVA with Tukey's post-hoc test (p < 0.05). The means of the tensile bond strengths were 1.43 ± 0.85 MPa, 0.91 ± 0.63 MPa, and 0.56 ± 0.39 MPa for the bioactive cement, resin cement, and RMGIC groups, respectively. A significant difference in tensile bond strength was observed between the bioactive cement and the RMGIC group (p < 0.05) but there was no significant difference in tensile bond strength between the resin cement group and the others. Types of luting cement influenced the tensile bond strength between PZCs and primary maxillary incisors. The bioactive cement showed higher tensile bond strength than the resin cement and RMGIC.

Comparative Assessment of Marginal Micro Leakage of Different Esthetic Restorative Materials Used on Primary Teeth: An In-vitro Study.

The aim of the current investigation was to evaluate the marginal microleakage of various esthetic restorative materials applied to primary teeth. A total of 75 noncarious primary molars that were removed for orthodontic intervention and teeth nearing exfoliation were chosen. One millimeter (mm) above the cementoenamel junction, on the buccal surface of the teeth, Class V cavities were prepared. William's graded periodontal probe was used to standardize cavity preparation on all teeth. 3 mm was the cavity's length, 2 mm in width, and 2 mm in depth. The teeth were then divided into three groups (25 samples in each group) according to the type of esthetic restorative material used. Group I: Resin-modified glass ionomer cement, Group II: Ormocer, Group III: Giomer. The samples underwent 500 cycles of thermocycling, with an immersion time of 60 seconds and a well time of 15 seconds, between 5 and 55°C. The samples were submerged in methylene blue dye for 24 hours at room temperature and dried. The samples were then divided into sections and examined with a stereomicroscope. Data was recorded and statistically analyzed. The least marginal microleakage was found in the ormocer group (1.22 ± 0.01) followed by resin-modified glass ionomer cement group (1.31 ± 0.07) and the giomer group (1.78 ± 0.03). There was a highly statistically significant difference found between resin-modified glass ionomer cement group and the ormocer group, resin-modified glass ionomer cement group and giomer group. And no significant difference was found between the ormocer group and the giomer group. The present study concluded that there was some amount of microleakage in primary teeth in all restorative materials examined in this in-vitro investigation. However, the marginal sealing ability of ormocer was found highest compared to resin-modified glass ionomer cement and Giomer materials. The primary reason dental restorations fail, particularly in Class V cavities, is microleakage since the margins of these restorations are typically found in the dentin or cementum. Assessing microleakage is a crucial step in determining the marginal integrity of restorative materials. Developing methods and resources that reduce the adverse effects caused by the restorative marginal seal failing would benefit from this. How to cite this article: Al Ghwainem A, Alqarni AS. Comparative Assessment of Marginal Micro Leakage of Different Esthetic Restorative Materials Used on Primary Teeth: An In-vitro Study. J Contemp Dent Pract 2024;25(1):58-61.

Assessing the Impact of Nano-Graphene Oxide Addition on Surface Microhardness and Roughness of Glass Ionomer Cements: A Laboratory Study.

Nanomaterials, including nano-graphene oxide (nGO), have emerged as promising modifiers for dental materials. Therefore, this study investigated the effect of incorporating nGO into conventional glass ionomer cement (CGIC) and resin-modified glass ionomer cement (RMGIC) on surface roughness and hardness. Sixty disk-shaped specimens (2 × 6 mm) were divided into six groups: CGIC, RMGIC, CGIC with 1 wt.% nGO, CGIC with 2 wt.% nGO, RMGIC with 1 wt.% nGO, and RMGIC with 2 wt.% nGO. Surface roughness (Ra) and Vickers microhardness (VHN) were measured using a surface profilometer and Vickers microhardness tester, respectively. Statistical analysis employed the Kruskal-Wallis and Mann-Whitney tests (p <0.05). The microhardness of RMGICs significantly increased with 1% and 2% nGO (p=0.017, P=0.001, respectively), while CGICs showed a significant decrease in VHN with nGO incorporation (p=0.001). VHN values of all CGIC groups were significantly higher than those of all RMGIC groups (p=0.001). Mean surface roughness values for all CGICs were significantly higher than those of RMGIC groups (p=0.001). Within the RMGIC groups, mean Ra values of RMGIC + 1 wt.% nGO and RMGIC + 2 wt.% nGO groups decreased significantly compared to the RMGIC control group (p=0.001, p=0.001, respectively). Among CGIC groups, mean Ra values of 1 wt.% and 2 wt.% nGO/CGIC groups were significantly higher than the CGIC control group (p=0.016, p=0.001). Incorporating nGO into RMGICs increased surface microhardness while reducing surface roughness, offering potential advantages for clinical applications. Conversely, adding nGO to CGICs increased surface roughness and decreased surface hardness. These findings emphasize the potential benefits of utilizing nGO in RMGICs and their implications in clinical practice.

Evaluation of the shear bond strength of a tricalcium silicate-based material to four self-adhering glass ionomer materials: an in vitro study.

This study aimed to evaluate and compare the shear bond strength (SBS) of EQUIA Forte HT with that of other restorative materials, including EQUIA Forte, glass ionomer cement (GIC), and resin-modified glass ionomer cement (RMGIC) when bonded to NeoMTA 2. A total of 120 holes were created in Teflon molds and filled with NeoMTA 2. The restorative materials were immediately applied using customized silicone molds. The samples were randomly divided into two main groups: one to measure the immediate SBS and the other to measure the delayed SBS. These two main groups were further divided into four subgroups based on the restorative material used: EQUIA Forte HT, EQUIA Forte, GIC, and RMGIC. The study groups showed statistically significant differences in the mean SBS (p < 0.0001). The immediate SBS of the RMGIC group (mean ± SD: 5.43 ± 1.22) was significantly higher than those of the GIC and EQUIA Forte groups, with no significant difference found compared to the SBS of EQUIA Forte HT. In the delayed SBS, both the RMGIC and EQUIA Forte HT groups (4.98 ± 0.67 and 4.93 ± 0.60, respectively) demonstrated significantly higher bond strengths than the GIC and EQUIA Forte groups (3.81 ± 0.57 and 4.2 ± 0.63, respectively). However, there were no statistically significant differences between the RMGIC and EQUIA Forte HT groups or between the GIC and EQUIA Forte groups. Based on our findings, EQUIA Forte HT has shown promising outcomes when used as a restorative material following pulpotomies, with results comparable to those of RMGIC.

Comparative Study of Bond Strength of Resin-Modified Glass Ionomer Cement and Flowable Composite with Glass Fiber Posts by Push-Out Test

Introduction: posts that have been properly fitted can withstand torsion and provide better retention. The purpose of this study was to evaluate the push-out bond strength of glass fiber posts cemented with different luting agents. The push-out bonding strength of glass fiber posts to the root canal was evaluated using resin-modified glass ionomer cement (RMGIC) and flowable composite (FC). Materials and Methods: Thirty single-rooted extracted human mandibular premolars were sectioned 2 mm coronal to the most incisal point of the cementoenamel junction. Root canals were instrumented and obturated with laterally condensed gutta-percha and root canal sealer (ADSEAL). Gutta-percha was removed from the canals to a depth of 11 mm and diameter post spaces with a 1.5 mm were prepared. The specimens were divided into the following 3 groups according to the luting agent used (n=10). The first group utilized FC (HARVARD, Germany) to coat the post, whereas the second group used RMGIC (Meron plus QM, VOCO, Germany). whereas the third group used Resin Cement (ITENA clinical, France) was used as the control. The specimens were cross-sectioned after 24 h. Specimens were cross-sectioned six millimeters thick into coronal using a sectioning machine. The strength of the bond between the luting cement and the posts was measured using push-out bond strength testing. We loaded the components at a cross speed of 0.5 mm/min on a universal testing machine until the bond failed. Results: The FC group had a 73.53N push-out bond strength, whereas the RMGIC group had a 133.55N, whereas the Resin Cement group had a 137.47N push-out bond strength. Conclusion: FC’s mean push-out bond strength score is lower than RMGIC’s and Resin Cement.

Comparison of the clinical outcomes of resin-modified glass ionomer and self-adhesive resin cementations for full-coverage zirconia restorations

Both resin-modified glass ionomer cement (RMGIC) and self-adhesive resin cement (SAC) may be suitable for cementation of full-coverage zirconia restorations. This retrospective study aimed to investigate the clinical outcomes of zirconia-based restorations cemented with RMGIC and compare them with those cemented with SAC. Cases of full-coverage zirconia-based restorations cemented with either RMGIC or SAC between March 2016 and February 2019 were evaluated in this study. The clinical outcomes of the restorations were analyzed according to the type of cement used. In addition, cumulative success and survival rates were evaluated according to the cement and abutment types. Non-inferiority, Kaplan-Meier, and Cox hazard tests were conducted (α=.05). A total of 288 full-coverage zirconia-based restorations (natural teeth, 157; implant restorations, 131) were analyzed. Loss of retention occurred in only one case; a single-unit implant crown cemented with RMGIC, which decemented 4.25 years post-restoration. RMGIC was non-inferior to SAC in terms of loss of retention (<5%). For single-unit natural tooth restorations, the four-year success rates in the RMGIC and SAC groups were 100% and 95.65%, respectively (p=.122). For single-unit implant restorations, the four-year success rates in the RMGIC and SAC groups were 95.66% and 100%, respectively (p=.365). The hazard ratios of all the predictor variables, including cement type, were not significant (p>.05). Cementation of full-coverage zirconia restorations of both natural teeth and implants using RMGIC and SAC yields satisfactory clinical outcomes. Furthermore, RMGIC is non-inferior to SAC in terms of cementation success. Cementation with RMGIC or SAC for full-coverage zirconia restorations has favorable clinical outcomes in both natural teeth and implants. Both RMGIC and SAC have advantages in the cementation of full-coverage zirconia restorations to abutments with favorable geometries.

Evaluation of the Clinical Impact and In Vitro Antibacterial Activities of Two Bioactive Restoratives against S. mutans ATCC 25175 in Class II Carious Restorations

Streptococcus mutans is a Gram-positive opportunistic bacterial pathogen and that causes dental caries and then restorative treatment remains the best clinical practice approach to repair and prevent dental caries. This study compared the antimicrobial performance of resin modified glass ionomer cement (RM-GIC) and ACTIVA restoratives by evaluating the S. mutans count, pH levels, and plaque index (PI) scores before and on the 7th day of restoration, and then determined the antimicrobial activities against S. mutans ATCC 25175 in both restoratives in vitro. Seventy-eight eligible Saudi female participants, with class II carious lesions, were randomly distributed into RM-GIC and ACTIVA restorative groups. We evaluated the S. mutans count by the serial dilution technique and salivary pH by using a portable pH meter. The PI scores were determined by Silness-Löe method and the antibacterial activity by the agar well diffusion method. Statistical analysis of normality distribution was performed with the Kolmogorov-Smirnov and the difference between groups was an analysis by paired t-test. In addition, the independent sample was compared with the independent samples t-test. Both groups reduced the S. mutans count, pH acidity, and PI scores, and this reduction was statistically significant on the 7th day of restoration (P < 0.05), preference for ACTIVA. The in vitro antibacterial activity against S. mutans ATCC 25175 showed a non-significant difference between both bioactive restorative materials (P < 0.05). The novel application of ACTIVA restorative material is a promising option for patients at risk of caries.

Influence of resin modified glass ionomer cement incorporating protein-repellent and antimicrobial agents on supragingival microbiome around brackets: an in-vivo split-mouth 3-month study.

To explore the influence of resin modified glass ionomer cement (RMGIC) adhesives containing protein-repellent and quaternary ammonium salt agents on supragingival microbiome, enamel and gingival health around brackets. Ten patients (21.4 ±3.5 years) about to receive fixed orthodontics were enrolled in this study. Unilateral upper teeth bonded with RMGIC incorporating 2-Methacryloyloxyethyl phosphorylcholine (MPC) and Dimethylaminohexadecyl methacrylate (DMAHDM) were regarded as experimental group (RMD), while contralateral upper teeth bonded with RMGIC were control group (RMGIC), using a split-mouth design. Supragingival plaque was collected from both groups before treatment (T0), and at 1 month (T1) and 3 months (T2) of treatment. High-throughput sequencing was performed targeting v3-v4 of 16S rRNA gene. Streptococcus mutans and Fusobacterium nucleatum quantification was done by qPCR analysis. Bracket failures, enamel decalcification index (EDI), DIAGNODent scores (Dd), plaque index (PI) and gingival index (GI) were monitored at indicated time points. Within 3 months, alpha and beta diversity of supragingival plaque had no difference between RMGIC and RMD groups. From T0 to T2, the relative abundance of Streptococcus depleted in RMD but remained steady in RMGIC group. Streptococcus, Prevotella, and Fusobacterium became depleted in RMD, Haemophilus and Capnocytophaga became depleted in RMGIC group but Prevotella enriched. Quantification of Fusbacterium nucleatum and Streptococcus mutans showed significant difference between RMGIC and RMD groups at T2. Teeth bonded with RMD had significant lower plaque index (PI) and DIAGNODent (Dd) score at T2, compared with teeth bonded with RMGIC (p < 0.05). No difference in bracket failure rate was examined between both groups (p > 0.05). By incorporating MPC and DMAHDM into RMGIC, the material could affect the supragingival microbial composition, inhibit the progress of plaque accumulation as well as the key pathogens S. mutans and F. nucleatum in the early stage of orthodontic treatment.

Twelve-month randomized controlled trial of 38% silver diamine fluoride with or without potassium iodide in indirect pulp capping of young permanent molars

BackgroundThe clinical and radiographic effectiveness of 38% silver diamine fluoride (SDF) with and without potassium iodide (KI) was tested and compared with resin-modified glass ionomer cement (RMGIC) in indirect pulp capping of deep carious lesions in young permanent molars. MethodsOne hundred eight permanent first molars with deep occlusal cavitated carious lesions in 49 children aged 6 through 9 years were randomly allocated into 3 groups (n = 36 molars per group) and treated with SDF plus KI, SDF, and RMGIC. RMGIC was used as a base and a resin-based composite restoration followed. Clinical assessments for secondary caries (primary outcome), postoperative pain, tooth vitality, and restoration success and quality rates according to Modified US Public Health Service and Ryge Criteria for Direct Clinical Evaluation of Restorations were performed after 3, 6, and 12 months. Periapical radiographs were obtained at baseline, 6 months, and 12 months. Outcomes were assessed using mixed effects multilevel logistic and linear regression analyses. ResultsThere were no significant differences (P = .26) among the groups at all times for secondary caries, postoperative pain, tooth vitality, clinical abscess, radiographic signs of pulpal pathology, restorations’ marginal adaption, anatomic form, and surface roughness. There was a significant difference (P = .03) in restoration color, marginal staining, and luster. The RMGIC group outperformed the 2 SDF groups in color and luster. ConclusionsThe authors did not find differences among the groups in preventing secondary caries or pain or in maintaining pulpal health. The RMGIC group had better restoration color and luster than both SDF groups and better marginal staining than the SDF group. Practical ImplicationsThe results of this study can help guide treatment decision making regarding use of SDF and SDF plus KI as indirect pulp capping materials in deep cavitated lesions.This clinical trial was registered at ClinicalTrials.gov. The registration number is NCT04236830.

Effect of Hydroxyapatite Synthesized from Tilapia Fish Scale Waste on the Shear Bond Strength of GIC and RMGIC to Enamel Layer (&lt;i&gt;In Vitro&lt;/i&gt; Study)

Indonesia is a country that has many types of freshwater fish, one of which is tilapia. The consumption of tilapia among the people of Indonesia is quite high. So that, it will produce a lot of fish scale waste. Fish scales can be used as a natural source of hydroxyapatite because they contain calcium. The aim of this study was to evaluate the effect of hydroxyapatite synthesized from tilapia fish scale (Oreochromis niloticus) on the shear bond strength of glass ionomer cement and resin modified glass ionomer cement to enamel layer. Hydroxyapatite was synthesized from tilapia fish scale (Oreochromis niloticus) by calcination method at 800°C. Sample was made from glass ionomer cement (GIC) and resin modified glass ionomer cement (RMGIC) combined with 2, 5 and 8%wt of hydroxyapatite, respectively. Sample was bonded to enamel layer of human premolar tooth. The shear bond strength of sample was tested by using Universal Testing Machine. The result showed that shear bond strength were increased for higher concentration of hydroxyapatite that added to glass ionomer cement or resin modified glass ionomer cement. The maximum of shear bond strength of GIC Group is 6,38 ± 0,05MPa after 8%wt hydroxyapatite addition. The maximum of shear bond strength of RMGIC Group is 6,59 ± 0,06 MPa after 8%wt hydroxyapatite addition. There were significance differences among all group tested (p &lt;0.05). It can be concluded that hydroxyapatite synthesized from tylapia fish scale can increase the shear bond strength of glass ionomer cement and resin modified glass ionomer cement.

The Effect of Loading Time on Color Stability of Various Restorative Materials Bonded to Silver Diamine Fluoride-Treated Demineralized Dentin.

AimTo investigate the effect of immediate versus one week later loading time on color stability of resin-based composite (RBC), resin-modified glass ionomer cement (RMGIC) and glass ionomer cement (GIC) restorative materials bonded to silver diamine fluoride (SDF)-treated demineralized dentin.Materials and MethodsNinety extracted premolars were randomly assigned to the following groups (n = 30 each): group-I (loaded with RBCs), group-II (loaded with RMGIC), and group-III (loaded with GIC). Each group was divided randomly into the following subgroups (n = 10): subgroup-A (control specimens) consisted of sound dentin and the restorative material was immediately loaded; subgroup-B consisted of demineralized dentin, underwent a SDF treatment and the restorative material was immediately loaded; subgroup-C consisted of demineralized dentin, underwent a SDF treatment and the restorative material was loaded 1 week later. The color difference (ΔE) and visual color changes (L*a*b*) of each specimen were calculated using a spectrophotometer. Data were analyzed using one-way ANOVA and post hoc Tukey’s tests to compare the ΔE values and a paired t test to compare the mean of L* a* b* coordinates.ResultsThe highest color stability was observed for GIC, followed by RMGIC, and the lowest color stability was observed for the RBC group. Significant differences within groups were noted in RBC and RMGIC (p < 0.001). Regarding the loading time of the restorative material, in RBCs, a significantly lower ΔE value was observed in the delayed loading group than in the immediate loading group (p = 0.035). In the RMGIC and GIC groups, there were no significant differences.ConclusionDelaying the loading time of the restorative material for 1 week following the application of SDF resulted in greater color stability than that of immediate loading. The caries arresting potential of SDF was revealed by the dark staining, which could be improved with the subsequent delayed restoration.

A Randomized Control Trial of Clinical Success and Acceptability of the Hall Technique and Resin-Modified Glass Ionomer Cement Restorations in Sealing Carious Primary Molars

Background: A paradigm shift in the caries management propelled interest in techniques for sealing caries and restorations with selective caries removal. Preformed Metal Crowns (PMCs) and Resin-Modified Glass Ionomer Cement (RMGIC) have been preferred choices of restorations for carious primary molars. This is the first study from India on the Hall Technique used to seal carious primary molars.&#x0D; Objective: To compare the clinical success and acceptability of the Hall Technique and RMGIC restorations in sealing carious primary molars.&#x0D; Methods: Sixty 7–8-year-old children having caries with ICDAS scores 3-5, requiring two or more restorations; a total of 140 teeth were randomized into Group A: HT (n1 = 73 teeth) or Group B: RMGIC (n2 = 67 teeth). A single calibrated operator assessed the ‘Major’ failures (abscess, secondary caries, new caries) and ‘Minor’ failures (dislodgement) over a period of 15 months. Children, parents, and operator rated the acceptability. The average time taken for each procedure was recorded.&#x0D; Results: ‘Major’ failures were statistically significantly higher in the RMGIC group (p=0.008). At the 12-month follow-up, the HT outperformed RMGIC restorations. Additional failures were seen in Group B: RMGIC restorations at 15-month follow-up, whereas no failures were seen with HT. The result was statistically not significant. Children, parents, and the operator preferred the Hall Technique, which was statistically significant (p&lt; 0.001).&#x0D; Conclusion: HT is a successful and acceptable technique and superior to RMGIC restorations with partial excavation of caries in primary molars but with mild postoperative discomfort.

Evaluation of the Surface Hardness and Roughness of a Resin-Modified Glass Ionomer Cement Containing Bacterial Cellulose Nanocrystals.

The purpose of this study was to evaluate the performance of a resin-modified glass ionomer cement (RMGIC) to which bacterial cellulose nanocrystals (BCNs) were added. BCNs were incorporated into the RMGIC powder in ratios of 0.3%, 0.5%, and 1% (w/w). One control and three experimental groups were enrolled in the study: unmodified RMGIC (control), 0.3% (w/w) BCN-modified RMGIC, 0.5% (w/w) BCN-modified RMGIC, and 1% (w/w) BCN-modified RMGIC. The surface hardness and surface roughness were the parameters assessed. The materials were characterized by scanning electron microscopy (SEM). The data were analyzed using the one-way ANOVA and Kruskal–Wallis tests for surface hardness and roughness, respectively. The addition of BCN resulted in the improvement of surface roughness in all the specimens compared with the control material. The RMGIC modified by 1% (w/w) BCN showed the lowest surface roughness (decreased by 52%) among all tested groups. However, BCN had a negative effect on the surface hardness of RMGIC. The group with 0.3% (w/w) BCN had the least decrease in microhardness (13%). According to the results, the RMGIC group modified by 1% (w/w) BCN had a smoother surface than the other groups. The surface microhardness of the RMGIC decreased after BCNs were added to it.

Push-Out Bond Strength of Resin-Modified Glass Ionomer Cement and Flowable Composite Luting Systems on Glass Fiber Post of Root Canal.

Background: Posts that have been properly fitted can withstand torsion forces and so provide better retention. The push-out bonding strength of glass fiber posts to the root canal was evaluated using resin-modified glass ionomer cement (RMGIC) and flowable composite (FC). Method: Forty single-rooted maxillary central incisors were used in the study. The samples were randomly divided into two groups of 20 teeth each. The crown-down procedure was used to clean and shape the pulp area. A Tenax fiber trans Coltene whaletene post was used by both groups. The first group utilized FC (Filtek Z 350 3M ESPE) to coat the post, whereas the second group used RMGIC (Rely X 3M ESPE). The specimens were cross-sectioned after 24 h. Specimens were cross-sectioned four millimeters thick into coronal and middle parts using a sectioning machine, yielding 40 specimens per group. The strength of the bond between the luting cement and the posts was measured using push-out bond strength testing. We loaded the components at a cross speed of 0.5 mm/min on a universal testing machine until the bond failed. Results: The FC group had a 4.80 N push-out bond strength, whereas the RMGIC group had a 7.11 N push-out bond strength. Conclusion: FC’s mean push-out bond strength score is lower than RMGIC’s.

Evaluation of enamel roughness after the removal of brackets bonded with different materials: In vivo study

The aims of this in vivo study were to evaluate the effect of bonding with resin-modified glass ionomer cement (RMGIC) and to assess enamel surface roughness before and after the removal of brackets bonded with composite or RMGIC from the maxillary central incisors. Fifteen orthodontic patients were selected for the study. For each patient, the teeth were rinsed and dried, and brackets were bonded with composite (Transbond XT) and RMGIC (Vitremer Core Buildup/Restorative). At the conclusion of orthodontic treatment, their brackets were removed. Dental replicas were made of epoxy resin in initial conditions (before bonded) and after polishing with an aluminum oxide disc system. Adhesive remnant index (ARI) and surface roughness was measured on the dental replicas and data were evaluated statistically by Mann-Whitney and paired t-test, respectively. No bracket debonding occurred during patients' treatment periods. It was verified that the ARI values of the two maxillary central incisors were similar (p = 0.665). For both bonding materials, the ARI value of 3 was predominant. After polishing, surface roughness was similar in the composite and RMGIC groups (0.245 μm and 0.248 μm, respectively; p = 0.07). In both groups, enamel surface roughness values were significantly lower after polishing compared with the initial condition (p < 0.001). RMGIC promoted efficiency in cementing brackets without fail during treatment; the choice of composite or RMGIC materials was not a factor that influenced the roughness of the enamel surface, however, polishing led to smoother surfaces than those found at the beginning of the treatment.

Evaluation of Microleakage under Sapphire Brackets Bonded with Three Different Orthodontic Adhesives after Thermocycling and Water Storage (An in Vitro Study)

Objectives: To evaluate and compare the microleakage between enamel-adhesive, bracket-adhesiveinterfaces at occlusal and gingival sides of sapphire brackets bonded with three different light-cure adhesivesystems after thermocycling and 2 months water storage.Materials and Methods: Sapphire brackets bonded to forty eight intact extracted upper premolar randomlyassigned according to orthodontic adhesive systems used into three equal groups (n=16) with different colorcoding: Conventional Transbond XT; Transbond XT plus self-etching primer; Resin-modified glass ionomercement (RMGIC) GC Fugi Ortho LC. After bonding and thermocycling, half of samples (8 teeth) in eachgroup, tested immediately after thermocycling and 24 hours of water storage and the remaining 8 teeth wereincubated in distilled water to be tested after 2 months of water storage. After each storage interval, sampleswere subjected to a dye penetration test and examined under a stereomicroscope with image analyzersoftware to assess the degree of microleakage in mm. Data was analyzed using the non-parametric tests.Results: After both storage time intervals, RMGIC group displayed higher microleakage than other groupswith high significant differences with Transbond XT group and more microleakage seen at gingival marginthan occlusal margin in all groups. The microleakage values increased after 2 months storage, but withoutsignificant differences.Conclusion: The type of adhesive systems could effect the amount of microleakage and higher valueunder brackets bonded with RMGIC with more microleakage gingivally than occlusally. The microleakageincreased after thermocycling with 2 months water storage.

Reinforcement effect of intra-orifice barrier materials in teeth treated with regenerative endodontic procedure: Research article.

Background. Regenerative endodontic treatment (RET) is a clinically advanced procedure for necrotic immature teeth. However, root canal walls of these teeth are brittle especially in the cervical region and need reinforcement. This in vitro study is conducted to evaluate the effect of intra-orifice barrier materials on the fracture resistance of immature teeth treated with regenerative procedure. Methods. Forty-eight maxillary central incisors were used. Twelve intact teeth were selected for the control group. Remained teeth were prepared using peeso drills to simulate immature teeth and assigned into three groups according to the intra-orifice barrier material placed over MTA (n = 12); Composite resin (CR), ProRoot MTA and Resin-modified glass ionomer cement (RMGIC). Fracture strength test was applied using a universal testing machine. One-way ANOVA and Tukey post hoc tests were used at P = 0.05. Results. A significant difference was obtained among groups (P < 0.05). MTA showed the lowest fracture resistance (P < 0.05). However, no significant difference was found among RMGIC, CR, and control groups (P > 0.05). Conclusion. Intra-orifice restorative materials have reinforcement affect in immature teeth treated with regenerative endodontic procedure. RMGIC or CR can be regarded as a viable choice to reduce the occurrence of cervical root fracture of immature teeth treated with a regenerative therapy.

Evaluation of Sealing Potential of Different Repair Materials in Furcation Perforations Using Dye Penetration: An In Vitro Study

The present study aimed to assess the sealing ability of various repair materials in furcation perforations using dye penetration. A total of 80 human first molars from mandible with unbroken enamel surfaces, which were extracted completely for periodontal reasons, were chosen. All extracted teeth were kept in a sterile solution up until further use. Endo-access bur was used to prepare endodontic access cavity, and a high-speed long shank round bur was used to create a planned perforation on the floor of pulp. All the specimens were randomly grouped (20 teeth in each group): Group I: control; group II: Pro-Root MTA; group III: resin-modified glass-ionomer cement (RM GIC); and group IV: Biodentin. After placement of repair materials in perforated furcation, the chamber of each tooth was accessed with 2% methylene blue dye. Later, a diamond disk was used to split the teeth buccolingually. A stereomicroscope (10×) was used to visualize the highest dye penetration. The least penetration was seen in teeth repaired by Biodentin group (0.88 ± 0.02), next by Pro-Root MTA group (1.24 ± 0.13) and resin-modified glass ionomer cement group (3.62 ± 0.46). A statistically significant difference was seen among different perforation repair materials by analysis of variance. A statistically significant difference (p value < 0.05) was found between each group, excluding group II v/s group IV. This study concluded that reduced dye penetration in perforation repair along the furcations and improved sealing ability are shown by biodentine group in comparison to Pro-Root MTA and resin-modified glass-ionomer cement group. Root perforations along the furcation that develop due to the endodontic procedures have a remarkable damaging effect on prognosis and frequently result in loss of secondary periodontal attachment, thus resulting in early loss of the involved tooth. Therefore, the selection of biocompatible repair material aids to enhance the treatment prognosis.

Comparison between Mineral Trioxide Aggregate Mixed with Water and Water-based Gel Regarding Shear Bond Strength with Resin-modified Glass Ionomer Cement and Composite

To compare between mineral trioxide aggregate (MTA) mixed with water and water-based gel regarding shear bond strength with resin-modified glass ionomer cement (RMGIC) and composite. In this study, 40 blocks of cylindrical shape were prepared with acrylic. These blocks were divided into four groups with each group consisting of 10 blocks: group-1A: MTA + distilled water + composite, group-1B: MTA + distilled water + RMGIC, group-2A: MTA + polymer + composite, and group-2B: RMGIC + MTA + polymer. After that, a universal testing machine was used for the measurement of shear bond strength. The acrylic blocks were placed under this machine. A blade with a knife-edge was used to provide a crosshead speed of 1 mm/minute. This was continued till bond of MTA in both forms (distilled water/gel) and restorative material failed. It was observed that a statistically significant difference was found between MTAw + composite and MTAg + composite resin but no statistically significant difference between MTAw + RMGIC and MTAg + RMGIC with p ≥ 0.05. It was found that a statistically significant difference was present between the RMGIC and composite groups within the same MTA type with p ≤ 0.05. It was concluded from the present study that MTA with a water-based gel has a better shear bond strength than composite resin and RMGIC materials. It has been found that MTA has different properties when it is mixed with polymer and water. Very few studies have been conducted in the past to compare MTA mixed with water and water-based gel regarding the shear bond strength with RMGIC and composite.