Resin-reinforced Glass Ionomer Cement Research Articles

Influence of cement type, excess removal, and polishing on the cement joint.

To compare marginal gap width and depth with different cementation systems, excess removal, and after polishing. In total, 80 composite crowns were milled, divided into ten groups, and cemented on identical artificial teeth. Eight crowns per group were fixed with (i) zinc phosphate cement (ZnOPh), (ii) glass-ionomer cement (GIC), (iii) resin-reinforced glass-ionomer cement (GIC mod), (iv) dual-curing adhesive composite (Comp dual), or (v) dual-curing self-adhesive composite (Comp SE dual). Excess removal was performed with a scaler after brief light-cure (tack-cure), final light-cure, during rubber or gel phase or by wiping with foam pellet. Curing was completed in chemical, dark cure, or light-curing modus. The specimens were polished and stored in water (37°C). The margins were digitized using a 3D laser-scanning microscope (VK-X100 series, Keyence). The width and the depth of the marginal gap were measured at 10 points between the crown margin and the preparation margin. The width after excess removal varied between 65.1 ± 15.7 µm (Comp dual, wipe, with polishing) and 208.6 ± 266.7 µm (Comp SE dual, dark cure, without polishing). The depth varied between 29.8 ± 22.2 µm (Comp dual, wipe, with polishing) and 89.5 ± 45.2 µm (Comp SE dual, dark cure, without polishing). The impact on gap width and depth was detected for fixation material, excess removal, and polishing. The gap depth and width depend on the luting material and the mode of access removal. Polishing can improve the gap quality, especially for GIC and resin-based systems.

Comparison of microleakage under orthodontic brackets bonded with five different adhesive systems: in vitro study

BackgroundOrthodontic treatment is associated with numerous adverse side effects, such as enamel discoloration, demineralization or even caries. The presence of microleakage between the enamel and the adhesive and between the adhesive and the base of the orthodontic bracket allows penetration of the bacteria, molecules, and liquids into the enamel and can lead to unpleasant “white spot lesions” or secondary caries beneath and around the brackets. The aim of this in vitro study was to evaluate microleakage in five adhesive systems commonly used in orthodontic practice for bonding brackets.MethodsOne hundred extracted premolars were divided into five groups of twenty teeth. Stainless steel Legend medium metal brackets were bonded to teeth using five adhesive systems: resin-reinforced glass ionomer cement GC Fuji Ortho LC (GCF) and composite materials Light Bond (LB), Transbond XT (TB), Trulock™ Light Activated Adhesive (TL), and GC Ortho Connect (GCO). The specimens were subjected to thermal cycling, stained with 2% methylene blue, sectioned with low–speed diamond saw Isomet and evaluated under a digital microscope. Microleakage was detected at the enamel-adhesive and adhesive-bracket interfaces from occlusal and gingival margins. Statistical analysis was performed using generalized linear mixed models with beta error distribution.ResultsMicroleakage was observed in all materials, with GCF showing the highest amount of microleakage. Composite materials GCO, TB, and LB exhibited the lowest amount of microleakage with no statistical difference between them, while TL showed a statistically significantly higher amount of microleakage (p < 0.001). The enamel–adhesive interface had more microleakage in all composite materials (GCO, LB, TB, and TL) than the adhesive bracket–interface (p < 0.001). The highest amount of microleakage occurred in the gingival region in all materials.ConclusionComposite materials showed better adhesive properties than a resin-reinforced glass ionomer cement. The presence of microleakage at the enamel-adhesive interface facilitates the penetration of various substances into enamel surfaces, causing enamel demineralization and the development of dental caries.

Comparison of Microleakage in Nanocomposite and Amalgam as a Crown Foundation Material Luted with Different Luting Cements under CAD-CAM Milled Metal Crowns: An In Vitro Microscopic Study.

Microleakage is a persistent problem despite advancement in materials and techniques in fixed prosthodontics. This leads to the importance of sound crown foundation material and luting agents used to maintain the marginal seal. The literature is deficient with studies, comparing microleakage under various crown foundation materials and luting agents, especially with CAD-CAM (computer-aided design and computer-aided manufacturing) metal crowns. This study was aimed to compare microleakage in a nanocomposite/dentinal bonding agent and amalgam/cavity varnish as crown foundation materials luted with two different luting cements: resin-reinforced glass ionomer cement and self-adhesive resin cement, under both dry and contaminated conditions. A hundred intact, caries-free human molars were prepared to receive crown foundation material and extra coronal restorations. Amalgams with cavity varnish and nanocomposites with dentinal bonding agent in both ideal and contaminated conditions were used as crown foundation materials. After restoration, each sample was cemented with a CAD-CAM milled metal crown using two different luting agents—resin-reinforced glass ionomer cement and self-adhesive resin cements both in ideal and contaminated conditions. Cementation was followed by thermocycling of samples, immersion in erythrosine B dye, embedding in clear auto polymerizing acrylic resin and sectioning to evaluate microleakage using stereomicroscope. The mean microleakage between different luting cements on the experimental side of the facial surface was 137.64 μm and 211.01 μm for resin-reinforced GIC and for self-adhesive resin cement was 119.78 μm and 150.42 μm, under ideal and contaminated condition, respectively. There was a significant difference in mean micro-leakage between different crown foundation material and cement groups used in the study. The composites and amalgam, both when used as crown foundation material and luted with use of technically advanced CAD-CAM metal crown with self-adhesive resin cement (in both ideal or contaminated condition), showed less microleakage than in resin-reinforced glass ionomer cement. Overall, the self-adhesive resin cement showed comparatively reduced microleakage in all combinations with different crown foundations. Thus, this combination can be used in daily clinical practice to provide better protection from further decay.

Bond strength and Weibull analysis of fiber posts luted with different cement types and mechanically aged

This study aimed to evaluate the influence of cement type and mechanical cycling on the push-out bond strength (σ) of fiber posts luted to root canals. Eighty bovine single-root teeth were prepared and the roots were included with chemically cured acrylic resin. The specimens were allocated into 8 groups (n = 10) considering the factors ‘cement’ (glass ionomer cement – GIC, resin reinforced glass ionomer cement – RRGIC, conventional dual-cure resin cement – CRC, and self-adhesive resin cement – SARC) and ‘mechanical cycling’ (non-aged and aged – mc). The fiber posts and roots dentin were treated according to the cement type and luted to root canals. Composite-cores were made for the groups submitted to mechanical cycling (1,000,000 cycles, 84 N, 4 Hz). Each root were cut into 4 disk-samples of 1.8 mm (thickness) and submitted to push-out testing. Data (MPa) were analyzed using two-way ANOVA, Tukey test (5%), and Weibull analysis. ANOVA revealed that cement (p < 0.001) was significant; however, the mechanical cycling had no effect on bond strength (p = 0.895). The CRC (4.36 ± 1.15 MPa), CRCmc (4.13 ± 0.75 MPa), GIC (4.29 ± 2.14 MPa), and GICmc (4.04 ± 1.18 MPa) groups showed higher (σ) than RRGIC (2.36 ± 1.00 MPa). Weibull Characteristic strength of the CRC and CRCmc were significantly higher than RRGICmc, and RRGIC. The mixed type of failure was the most common. Conventional dual-cure resin cement and glass ionomer cement presented higher push-out bond strength to root dentin regardless of mechanical cycling.

Lithium Disilicate Ceramic Endocrown Biomechanical Response According to Different Pulp Chamber Extension Angles and Filling Materials.

The purpose of this study is to evaluate the effect of pulp chamber extension angles and filling material mechanical properties on the biomechanical response of a ceramic endocrown. A 3D model of maxillary molar that underwent endodontically treatment was exported to computer aided design software to conduct finite element analysis (FEA). The endocrown model was modified considering different pulp chamber extension angles (right angle; 6°, 12° and 18° of axial divergence). The solids were imported into the computer aided engineering software in Standard for the Exchange of Product Data (STEP) format. Nine different filling materials were simulated to seal the orifice of the root canal system under each endocrown restoration (resin composite, bulk-fill resin composite, alkasite, flowable resin composite, glass ionomer cement, autocured resin-reinforced glass ionomer cement, resin cement, bulk-fill flowable resin composite, zinc oxide cement), totaling 36 models. An axial load (300 N) was applied at the occlusal surface. Results were determined by colorimetric graphs of von-Misses stress (VMS) and Maximum Principal Stress (MPS) on tooth, cement layer, and endocrown restorations. VMS distribution showed a similar pattern between the models, with more stress at the load region for the right-angled endocrowns. The MPS showed that the endocrown intaglio surface and cement layer showed different mechanical responses with different filing materials and pulp chamber angles. The stress peaks plotted in the dispersion plot showed that the filling material stiffness is proportional to the stress magnitude in the endocrown, cement layer and tooth adhesive surface. In addition, the higher the pulp chamber preparation angle, the higher the stress peak in the restoration and tooth, and the lower the stress in the cement layer. Therefore, 6° and 12° pulp chamber angles showed more promising balance between the stresses of the adhesive interface structures. Under the conditions of this study, rigid filling materials were avoided to seal the orifice of root canal system when an endocrown restoration was planned as rehabilitation. In addition, the pulp chamber axial walls were prepared between 6° and 12° of divergence to balance the stress magnitude in the adhesive interface for this treatment modality.

Comparing effectiveness of rubber dam and gingival displacement cord with copy abutment in reducing residual cement in cement-retained implant crowns: A crossover RCT.

To evaluate the amount of residual cement after cementation of implant crown abutments with rubber dam and retraction cord with copy abutments techniques. Thirty single posterior metal-ceramic implant-supported restorations were delivered to 20 patients. The crowns were fabricated with occlusal openings obturated with composite, and then luted with resin-reinforced glass-ionomer cement on customised standard abutments. The cementation procedure was performed twice in the same specimens using rubber dam (group 1) and retraction cord with copy abutment (group 2). If no cement remnants were seen on periapical radiographs after cleaning, the crown-abutment unit was dismounted. All quadrants of the specimens were photographed to calculate the percentage proportions of residual cement area. Mann-Whitney and Kruskal-Wallis tests were used for statistical analysis. In each group, 120 measurements were performed (30 implants, 4 surfaces each). The median percentage ratio with interquartile range (IQR) between the cement remnant area and total specimen area was 1.39% (IQR 0.77%-2.29%) and 0.58% (IQR 0.31%-1.33%) in groups 1 and 2, respectively. Lesser cement remnants were found in group 2 with a statistically significant difference (p<.001). The comparison of the mesial, distal, buccal, and lingual surfaces in each group showed no statistically significant differences between them (group 1, p=.482; group 2, p=.330). The retraction cord and copy abutment reduced the excess cement more efficiently than the rubber dam did. Notwithstanding, undetected cement remnants were observed with both methods, and neither should be considered reliable in clinical applications.

Effect of building-up core material’s kind on location of fracture for endodontically treated teeth restored using glass Fiber post (in-vitro study)

Introduction: The quality of the material used to build-up the cores of the treated and restored teeth with fiberglass posts affect the location of fracture, as it plays an important role in the durability and durability of the coronary root restoration under different oral environment conditions. The aim of the study: Study of the effect of the core building-up material quality of three different materials on the location of fracture for a group of lower premolars after treating the core and restoring them with fiberglass posts. Research materials and methods: The research sample consisted of (30) lower first laughs, as these teeth were extracted in the course of orthodontic treatment (free from any defects) and stored with distilled water. The clinical crowns of these teeth were cut so that a coronary tissue was kept 2mm high above the enamel-cemento junction. These teeth were treated with pulp and restored with fiberglass posts. The research sample was divided into three groups, each consisting of (10) premolars, according to the type of core building-up material. 1. Composite Resin (IVOCLAR, T-Econom, Liechtenstein) Group T. 2. Flow composite resin (IVOCLAR, Titric N-Flow, Liechtenstein) Group F. 3. Resin Reinforced Glass Ionomer Cement (3M ESPE, Vitermer, USA) Group G. The teeth were crowned with Nickel-Chrome crowns and then an oblique force was applied at an angle of 45 to the tooth axis using a general mechanical testing device at a speed of 1mm / min until failure occur. Results: It was found that group T premolars restored with composite resin had nine Cervical Fracture states and once in middle while the locations of fracture fore premolars restored with Flow resin had eight Cervical Fracture states and twice in Middle, and locations of fracture for premolars Restored with Glass ionomer cement had ten Cervical Fracture, and significant differences were observed between groups (P =1). Conclusion: As it turns out, there is no correlation to the core building-up material in the failure model.

Finite Element Analysis in Setting of Fillings of V-Shaped Tooth Defects Made with Glass-Ionomer Cement and Flowable Composite

The aim of the present paper is to investigate the deformation–stress state of fillings of V-shaped tooth defects by finite element analysis (FEA). Two different materials are used—auto-cured resin-reinforced glass-ionomer cement (GIC) and flowable photo-cured composite (FPC). Two materials are placed into the cavity in one portion, as before the application of the composite the cavity walls are covered with a thin adhesive layer. Deformations and equivalent von Mises stresses are evaluated by FEA. Experimental study of micro-leakage is performed. It is established that there is an analogous non-homogeneous distribution of equivalent Von Mises stresses at fillings of V-shaped defects, made with GIC and FPC. Maximum stresses are generated along the boundaries of the filling on the vestibular surface of the tooth and at the bottom of the filling itself. Values of equivalent Von Mises stresses of GIC fillings are higher than that of FPC. Magnitude and character of deformation distribution at GIC and FPC fillings are similar—deformation is maximum along the vestibular surface of the filling and is 0.056 and 0.053 mm, respectively. In FPC fillings, the adhesive layer, located along the cavity/filling boundary, is characterized with greatest strain. The experimental study of micro-leakage has confirmed the adequacy of models used in FEA.

Enamel gloss changes induced by orthodontic bonding.

The purpose of this study was to assess enamel gloss changes induced by orthodontic bracket bonding with a light-cured composite or a light-cured resin-reinforced glass ionomer cement. The Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Greece. Laboratory study. A total of twenty extracted upper human first premolars were included in this study and each tooth served as a control for itself. Their buccal surfaces were subjected to 60o-angle gloss measurement (G%60) with a standardized and secure repeated analysis of the same site. After baseline evaluation, a bracket was bonded on the buccal surface of each tooth. Half of the specimens were bonded with acid-etching and a light-cured composite whereas the other half with a light-cured resin-reinforced glass ionomer cement without prior enamel conditioning. Gloss measurements were repeated after bracket debonding and removal of the composite/glass ionomer cement with an 18-fluted carbide bur. Gloss differences between the two measurement conditions (baseline and post-debonding) were analyzed through linear regression with standard errors derived using the bootstrap method. Level of significance was set at a < 0.05. A statistically significant difference was detected between the tested groups for the outcome of interest. Teeth bonded with light-cured composite exhibited larger enamel gloss changes as compared to resin-reinforced glass ionomer cement (β = 0.74; 95% CIs: 0.10, 1.38; p = 0.02). Bracket bonding with two common bonding protocols (acid-etching with a light-cured composite vs. no etching with resin reinforced glass-ionomer cement) and subsequently debonding and adhesive removal with an 18-fluted carbide bur induced enamel gloss changes.

Impact of two early treatment protocols for anterior dental crossbite on children's quality of life.

ABSTRACTObjective: To assess the impact of two early treatment protocols for anterior dental crossbite on children’s quality of life. Methods: Thirty children, 8 to 10 years of age, with anterior dental crossbite, participated in this study. Individuals were divided into two groups: Group 1 - 15 children undergoing treatment with an upper removable appliance with digital springs; Group 2 - 15 children undergoing treatment with resin-reinforced glass ionomer cement bite pads on the lower first molars. Quality of life was evaluated using the Brazilian version of the Child Perceptions Questionnaire (CPQ8-10), which contains four subscales: oral symptoms (OS), functional limitations (FL), emotional well-being (EW), and social well-being (SW). A higher score denotes a greater negative impact on children’s quality of life. Children answered the questionnaire before treatment (T1) and twelve months after orthodontic treatment onset (T2). Descriptive statistics, the Wilcoxon test and analysis of covariance (ANCOVA) were performed. Results: Children’s mean age was 9.07 ± 0.79 years in Group 1 and 9.00 ± 0.84 years in Group 2. For Group 1, the FL and EW subscale scores and the overall CPQ8-10 were significantly higher in T1 as compared to T2 (p= 0.004, p= 0.012 and p= 0.015, respectively). For Group 2, there were no statistically significant differences. The ANCOVA showed no significant difference regarding quality of life at T2 between groups, after controlling for quality of life measures at T1.Conclusions: The difference regarding the impact on quality of life between groups is not related to the protocol used.

Forensic applications: Fluorescence properties of tooth-coloured restorative materials using a fluorescence DSLR camera

The objective of this study was to compare the fluorescence properties of dry and wet samples of contemporary tooth-coloured restorative materials using a fluorescence based DSLR camera and a variety of LEDs emitting different wavelengths of visible light as excitation sources. The materials examined included resin composites; ceramics and hybrid restorative materials such as ormocers, Vita Enamic™ and resin reinforced glass-ionomer cements. The levels of fluorescence for each sample under different combinations of incident light wavelengths and filters was analysed by using histogram data for colour channels from Adobe Photoshop software. Fluorescence patterns were influenced by water sorption of the materials. UV-A/Violet light (405±nm) produced the greatest range of luminosity values (10–204) amongst the tooth-coloured restorative materials, and showed the greatest differences between restorations and tooth structure. The best filter combinations with violet light were orange or yellow filters. Under ultraviolet excitation, Fuji VIII A2 exhibited a unique bright pink fluorescence emission, while VitaEnamic™, ormocer and glass-ionomer cements emitted bluish-pink fluorescence emissions. In conclusion, restorative materials exhibited varied emission pattern under UV-A (405nm) light, which enables their detection and differentiation from natural tooth structure.

Comparison of two different debonding techniques in orthodontic treatment.

The purpose of this research is to investigate whether and how the adhesive bond failure site varied in relation to the material used for the orthodontic bonding and debonding technique applied. Two different methods of orthodontic debonding were included in our survey; cutters for orthodontics and debonding plier. Three different materials for the adhesion of the bracket: composite light curing, self-curing composite and glass ionomer cement. The remaining amount of adhesive on the tooth surface is an important parameter that gives information on how the location of the posting site varied during the debonding. 60 dental elements, maxillary and mandibular, previously extracted for orthodontic reasons, as well as periodontal, were included in our research. We investigated a possible significant correlation between different variables (debonding technique and materials for membership) and the ARI index. The use of orthodontic cutters or debonding pliers does not affect the adhesive bond failure site and both techniques have a tendency to leave a significant amount of adhesive on the surface enamel. In the resin-reinforced glass ionomer cements, detachment occurs at the interface enamel-adhesive and this pattern of detachment increases the risk of the enamel damage during debonding. In both types of composite resins (photopolymerizable or self-curing), the detachment occurs at the interface bracketing adhesive. In this case the amount of remaining adhesive material on the tooth must be removed with further methods, which in addition, increase the risk of iatrogenic injury as well as the working hours.

Evaluation of cavity wall adaptation of bulk esthetic materials to restore class II cavities in primary molars.

The purpose of the study was to assess the cavity wall adaptation and gap formation of a bulk fill composite resin and reinforced conventional glass ionomer cement and a resin-modified glass ionomer cement in class II restorations on primary molars. Standardized class II slot cavity preparations were prepared in exfoliating primary molars. Teeth were restored with one of the three tested materials (n=10): SonicFill bulk fill composite resin (SF), EQUIA Fil conventional reinforced glass ionomer cement (EQF), and Vitremer resin-reinforced glass ionomer cement (VT). Cavity wall adaptation of the restorations was investigated by computerized X-ray micro-tomography and the percentage void volume fraction (%VVF) was calculated. Same specimens were sectioned and the interfaces were evaluated by reflection optical microscopy to measure the percentage linear length (%LD) of the interfacial gaps. Samples were further evaluated by environmental scanning electron microscopy (ESEM). EQF and SF showed significantly lower %VVF and %LD values than VT (p<0.05). This was in accordance with ESEM findings where VT illustrated extended interfacial gaps. SF and EQF showed better cavity wall adaptation than VT in class II restorations on primary molars. High-strength conventional glass ionomer cement (GIC EQF) and bulk fill composite SF requiring fewer application steps and reduced operating time than the traditional composite resin materials showed good cavity wall adaptation. Short operating time and good cavity wall adaptation are advantages of the materials in restorative and pediatric dentistry, especially while working on children with limited attention span.

Compressive fatigue limit of four types of dental restorative materials

The purpose of this study was to evaluate the quasi-static compressive strength and the compressive fatigue limit of four different dental restorative materials, before and after aging in distilled water for 30 days. A conventional glass ionomer cement (Fuji IX GP; IG), a zinc-reinforced glass ionomer cement (Chemfil rock; CF), a light curable resin-reinforced glass ionomer cement (Fuji II LC; LC) and a resin-based composite (Quixfil; QF) were investigated. Cylindrical specimens (4mm in diameter and 6mm in height) were prepared according to the manufacturer׳s instructions. The compressive fatigue limit was obtained using the staircase method. Samples were tested in distilled water at 37°C, at a frequency of 10Hz with 105 cycles set as run-out. 17 fatigue samples were tested for each group. Two-way ANOVA and one-way ANOVA followed by Tukey׳s post-hoc test were used to analyze the results. Among the four types of materials, the resin-based composite exhibited the highest compressive strength (244±13.0MPa) and compressive fatigue limit (134±7.8MPa), followed by the light-cured resin reinforced glass ionomer cement (168±8.5MPa and 92±6.6MPa, respectively) after one day of storage in distilled water. After being stored for 30 days, all specimens showed an increase in compressive strength. Aging showed no effect on the compressive fatigue limit of the resin-based composite and the light-cured resin reinforced glass ionomer cement, however, the conventional glass ionomer cements showed a drastic decrease (37% for IG, 31% for CF) in compressive fatigue limit. In conclusion, in the present study, resin modified GIC and resin-based composite were found to have superior mechanical properties to conventional GIC.

Silicone Disclosing Material used after Ceramic Surface Treatment Reduces Bond Strength.

To evaluate the effect of a silicone disclosing procedure performed at different timepoints on the shear bond strength (SBS) of cements (self-adhesive composite cement, self-etch composite cement, resin-reinforced glass-ionomer cement) to different substrates (zirconia, lithium disilicate, bovine dentin). The substrate/cement combinations were assigned to two groups (n = 15) according to the timepoint, at which the vinyl polyether silicone disclosing agent was applied: after (experimental groups, EXP) or before (control groups, CTRL) specific micromechanical treatments of the substrate surface. To increase standardization, the cements were applied into rubber rings (2.2 mm diameter x 1.0 mm thickness) positioned on the substrate surface. After luting procedures, all specimens were stored in 37°C distilled water for 24 h, then subjected to SBS testing using a wire loop of 0.2 mm diameter at a crosshead speed of 1 mm/min until failure. Failure analysis was performed for all tested specimens. SBS data were submitted to Weibull analysis. The silicone disclosing procedure performed after micromechanical surface treatment reduced the characteristic shear bond strength to zirconia and lithium disilicate when compared to CTRL. However, for dentin specimens, there was no significant difference between CTRL and EXP for any of the cements investigated. Failure analysis showed a predominance of interfacial failures. The silicone disclosing procedure performed after the micromechanical treatment of ceramic surfaces negatively affected the cement bond strength. Therefore, after using it to check the fit of a prosthesis, clinicians should carefully clean the ceramic surface.

Time-related bond strength of resin-reinforced glass ionomer cement under various light exposure conditions

PurposeThis study's purpose was to determine the time-related bond strengths of light-cured resin-reinforced glass ionomer cement (LCGIC) under various conditions of light exposure. Materials and methods480 freshly extracted bovine mandibular incisors were randomly divided into 32 groups. The study was performed in 4 light curing conditions, at 4 bond-testing times, and by 2 bond testing methods. For dental curing lights, LED using a source consisting of high intensity light-emitting diode, TQH (tungsten quartz halogen lamp) and PAC (plasma arc lamp) were used. Light exposure from 2 directions was performed under 4 conditions: for 5s with LED (LED-5s), for 10s with LED (LED-10s), for 20s with TQH, and for 3s with PAC. Tensile and shear bond tests were performed at 4 time-points after light exposure, i.e. 0min, 3min, 30min, and 24h. ResultsLED had the highest peak output by 44.7mW/cm2 at 458nm. Significant increase over time of tensile and shear bond strength was observed in all of the groups. TQH and PAC had low tensile bond strength just after the exposure. LED-10's demonstrated significantly higher tensile and shear bond strength compared with other groups. ConclusionAlthough LED and PAC showed approximately peak irradiance five times higher than TQH, there is no significant difference in tensile and shear bond strength between TQH and PAC. It appears that LCGIC would have provided greater bond strength under various conditions of LED-10's.

The effects of in vitro fluoride mouth rinse on the antibacterial properties of orthodontic cements

To investigate the ability of orthodontic cements to regain their antibacterial effect after aging for 1 month, followed by 2 weeks of fluoride 'recharging' through daily fluoride rinse. Four orthodontic cements were tested: composite resin-based materials (Transbond XT and Transbond Plus), a conventional glass ionomer cement (CX Plus) and dual-cured resin-reinforced glass ionomer cement (Fuji ORTHO LC) by direct contact test. After polymerization and a 30-day aging process, the samples were rinsed daily with 0.05% NaF solution for 14 days. Twenty-four hours after the last fluoride rinse, Streptococcus mutans cells (approximately 1 x 10(6) ) were placed on the surface of each sample for 1 h at 37°C to establish direct contact. Bacterial growth was monitored for 24 h by temperature-controlled spectrophotometry. Similar experiments were conducted after aging for 48 h and 72 h after the last fluoride rinse. One-way anova, two-way anova, and Tukey's multiple comparison test were applied to the data. Twenty-four hours after the last fluoride rinse, the resin-modified glass ionomer and the glass ionomer showed potent antibacterial properties, whereas the composite-based material Transbond XT encouraged bacterial growth. After 72 h, only Fuji Ortho LC maintained its bacteriostatic properties while all the other tested materials showed no antibacterial activity. Fourteen days daily fluoride rinse temporarily revives the antibacterial properties of the resin-modified glass ionomer cement and glass-ionomer-based cement.

In vivo biocompatibility versus degree of conversion of resin‐reinforced cements in different time periods

This study focused on test the null hypothesis that there is no difference between the degree of conversion and biocompatibility of different resin reinforced glass ionomer cements (RRGICs). Forty-eight male Wistar rats were used, distributed into four groups (n = 12), as follows: Group C (Control, polyethylene), Group FOB (Fuji Ortho Band), Group UBL (Ultra band Lok), and Group MCG (Multicure Glass), in subcutaneous tissue. The events of edema, necrosis, granulation tissue, multinuclear giant cells, young fibroblasts, and collagen formation were analyzed at 7, 15, and 30 days. The degree of conversion was evaluated by the Fourier method. Biocompatibility and degree of conversion were assessed using the Kruskal-Wallis and Dunn tests, and ANOVA and Tukey's test, respectively (P < 0.05). It was observed that, there was significant difference between Groups FOB and UBL for the presence of young fibroblasts at 15 days (P = 0.034) and between the Control and MCG Groups for the presence of multinucleated giant cells at 30 days (P = 0.009). Monomer conversion increased progressively until day 30, with significant difference between Group FOB and Groups UBL and MCG (P = 0.013) at 15 days. The null hypothesis was partially accepted, Fuji Ortho Band showed a less monomer conversion and a smaller number of young fibroblasts in the time of 15 days.

Evaluation of Shear Bond Strength of Resin Reinforced Glass Ionomer Cement Modified by Nano-hydroxyapatite on Ceramic Bracket Debonding Using Full-dimension Wire

Aim: Using fluoride releasing materials such as Glass Ionomer Cement (GIC), can control the demineralization around brackets. In this study, the shear bond strength of resin reinforced GIC modified by Nano-hydroxyapatite (NHA) on ceramic bracket debonding is evaluated. In addition, using full-dimension wire for safe debonding is also examined. Study Design: Original article. Place and Duration of Study: Department of Dentistry, Shahed University, Tehran, IRAN, June 2013. Methods and Material: 80 extracted human premolars received from a clinic were partitioned into 4 groups. Bonding materials used in each group was as follows: Group 1: Transbond XT as a control group, Group 2: Resin Modified GIC (RMGIC), Group 3: RMGIC added 5% NHA and Group 4: RMGIC added 10% NHA. In all groups the enamel was etched with 37% phosphoric acid and ceramic brackets were used. Each group halved into 2 subgroups which just in one of them full dimension wire was employed at the time of debonding. The shear bond strength, Adhesive Remnant Index (ARI) and bracket failure figures were collected for each group. The data was latter analyzed using one-way Analysis Of Variance (ANOVA), Tukey’s HSD (Honestly Significant Difference) Post-hoc Original Research Article Article Annual Research & Review in Biology, 4(10): 1578-1586, 2014 1579 and Kruskal Wallis Test methods. Results: According to ANOVA, RMGIC added 5% NHA has no negative effect while adding 10% NHA lowered the shear bond strength significantly. No bracket failure occurred at debonding, either using or not using full dimension wire. ARI for RMGIC groups were more cohesive than the control group. Conclusion: RMGIC containing 5% NHA contributes bond strength similar to composite resins, in bonding ceramic brackets, while its known demineralization resistance is a favor.

Solubility and porosity of new nanostructured calcium silicate cement

Introduction. Calcium silicate cements are most commonly used materials in endodontics for many indications due to their exceptional biological and physical properties. The aim of this study was to assess solubility and porosity of new experimental nanostructured calcium silicate cement. Material and Methods. A novel nanostructured calcium silicate cement (CS), commercialized calcium silicate cement (Biodentin), traditional glass ionomer cement (GIC) (Micron Superior) and resin-reinforced glass ionomer cement (Fuji VIII) were used in this study. All materials were prepared as per manufactuers? instructions, placed in metal rings of 16?2 mm diameter and kept in an incubator at 37?C for 24 hours. After that they were weighed and put in plastic containers filled with 25 ml of water for additional 24 hours. Then after all samples were weighed again and resorption and solubility were calculated. Results. The highest solubility was found for new CS cement (12.45) followed by conventional GIC Micron Superior (11.5) and Biodentin (6.1) whereas the lowest solubility was for resin reinforced GIC Fuji VIII (3.8). These differences were statistically significant (p&lt;0.005). The highest absorption was also observed in new CS cement (24.15), followed by Biodentin (18.5) and Micron superior (17.95) while the lowest was for GIC Fuji VIII (7.75). These differences were also statistically significant except between Micron Superior and Biodentin. Conclusion. Solubility and porosity of new nanostructured calcium silicate cement were significantly higher than for traditional calcium silicate cement, traditional GIC and resin-reinforced GIC.