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Objective:The aim of this study was to compare the microhardness of high viscosity glass ionomer, glass carbomer (GC) and bioactive restorative material (BRM) exposed to different polymerization times, and the intrapulpal thermal changes they caused on teeth.Methods:Sixty human molar teeth were used in this study. During Class I cavity preparation,1 mm dentine thickness was left between the pulp chamber and occlusal cavity floor.Teeth were randomly divided into six groups. Group 1: restored with high viscosity glass ionomer cement (HV-GIC), cured for 20 sec., Group 2: restored with HV-GIC, cured for 40sec., Group 3: restored with conventional glass ionomer cement, cured for 60 sec., Group 4: restored with GC and cured for 90 sec., Group 5: restored with BRMs, cured for 20 sec., Group 6: restored with BRM, cured for 40 sec. All glass ionomer cements were polymerized with a LED light curing unit except GC groups. GC groups were cured with a special thermocure lamp. As soon as the materials were placed in the cavities, temperature increase on the tooth during setting/polymerization reactions were measured with a thermocouple wire connected to a data logger. All of the specimens were polished with discs.Then, microhardness values were evaluated from three different points. Data were analyzed using one-way ANOVA, Tukey test and paired t-tests (p

The topic of fluoride release and uptake by glass-ionomer (glass polyalkenoate) dental cements is reviewed. The study was based on a literature search carried out using PubMed. The main key words used were glass-ionomer and fluoride, and further refinements were made by adding the keywords anti-microbial, anti-caries and remineralization. Papers were selected from the initial search, which concentrated on fundamental aspects of fluoride release, including kinetics and the influence of the cement composition, and resulting clinical performance against caries. Other relevant papers were cited where they added useful and relevant data. From these published papers, it was possible to explain the detailed mechanism of fluoride release by glass-ionomer cements and also its uptake. Fluoride release has been shown to be a two-step process. In neutral solutions, the steps can be divided into early wash-out and long-term diffusion. In acid conditions, the early wash-out remains, though with greater amounts of fluoride released, and the long-term release becomes one of slow dissolution. The effect of fluoride on the viability of oral micro-organisms has been described, and glass-ionomers have been shown to release sufficient fluoride to reduce the size and viability of adjacent populations of oral bacteria. The effect of low levels of fluoride on the remineralization of tooth tissue has been considered. Levels needed to increase remineralization are much lower than those needed to adversely affect oral bacteria, from which we conclude that glass-ionomers release sufficient fluoride to promote remineralization. Despite this, there remains uncertainty about their overall contribution to sound oral health, given the widespread use of other sources of fluoride, such as toothpastes. Glass-ionomer cements of both types (conventional and resin-modified) release fluoride for considerable periods of time after setting. They release sufficient fluoride to inhibit the growth of oral bacteria, and this level is more than sufficient to promote remineralization of tooth mineral. This shows that these materials provide sufficient fluoride to inhibit caries though, with the widespread use of fluoridated products such as toothpaste, this may have only limited benefit on the oral health of patients. [ABSTRACT FROM AUTHOR]

Objectives: This paper reviews the chemical behaviour of glass polyalkenoate (glass-ionomer) dental cements, both conventional and resin-modified, in contact with natural tissues, with the aim of determining whether these materials can be considered to be bioactive. Data: Relevant papers describing the behaviour of bioactive glasses and ceramics, and glass-ionomer (glass polyalkenoate) cements have been identified using PubMed and Science Direct. This has allowed a comparison to be made between the behaviour of glass-ionomers and the speciality glasses and ceramics that are widely classified as bioactive, a designation considered valid for over fifty years. More recent papers concerning bioactive metals and polymers have also been studied and both in vitro and in vivo studies are included. Sources: Have included general papers on the chemistry and biological behaviour of bioactive glasses and ceramics, as well as papers on glass-ionomers dealing with (i) ion release, (ii) bonding to the surface of teeth, (iii) influence on surrounding pH and (iv) interaction with bone. Conclusion: The literature shows that glass-ionomers (glass polyalkenoates) have three types of behaviour that are similar to those of bioactive glasses as follows: Formation of direct bonds to living tissue (teeth and bones) without fibrous capsule; release of biologically beneficial ions; and change of the local pH. However, in in vitro tests, they do not cause calcium phosphate to precipitate from solutions of simulated body fluid, SBF. Despite this, studies show that, in patients, glass-ionomers interact chemically with hard tissues and this suggests that may indeed be considered bioactive.

AbstractThe topic of fluoride release and uptake by glass-ionomer (glass polyalkenoate) dental cements is reviewed. The study was based on a literature search carried out using PubMed. The main key words used were glass-ionomer and fluoride, and further refinements were made by adding the keywords anti-microbial, anti-caries and remineralization. Papers were selected from the initial search, which concentrated on fundamental aspects of fluoride release, including kinetics and the influence of the cement composition, and resulting clinical performance against caries. Other relevant papers were cited where they added useful and relevant data. From these published papers, it was possible to explain the detailed mechanism of fluoride release by glass-ionomer cements and also its uptake. Fluoride release has been shown to be a two-step process. In neutral solutions, the steps can be divided into early wash-out and long-term diffusion. In acid conditions, the early wash-out remains, though with greater amounts of fluoride released, and the long-term release becomes one of slow dissolution. The effect of fluoride on the viability of oral micro-organisms has been described, and glass-ionomers have been shown to release sufficient fluoride to reduce the size and viability of adjacent populations of oral bacteria. The effect of low levels of fluoride on the remineralization of tooth tissue has been considered. Levels needed to increase remineralization are much lower than those needed to adversely affect oral bacteria, from which we conclude that glass-ionomers release sufficient fluoride to promote remineralization. Despite this, there remains uncertainty about their overall contribution to sound oral health, given the widespread use of other sources of fluoride, such as toothpastes.

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Purpose: The objective was to assess the effect of fissure depth and enamel surface preparation protocols on penetration of resin-based, giomer and glass-ionomer fissure sealants.Materials and Methods: Ninety extracted third molars were assigned into three groups according to the material used. All three groups were subsequently divided depending on tooth preparation: no pretreatment or surface preparation with 10% polyacrylic acid, 37% phosphoric acid, or self-etching adhesive. In addition, Er,Cr:YSGG laser or air abrasion were employed in all subgroups. The penetration was evaluated using scanning electron microscopy.Results: The groups that were pretreated with an appropriate acid resulted in superior penetration of glass-ionomer and resin-based sealants when compared with other surface preparation protocols (p < 0.05). The exception was teeth treated with both air abrasion and acid etching. Both preparation protocol and fissure depth significantly affected the sealant penetration (p < 0.05), but fissure depth had a greater impact on fissure penetration than did enamel surface pretreatment.Conclusion: All investigated materials exhibit similar properties regarding sealant penetration. Penetration of a fissure sealant is significantly influenced by the fissure depth. In regard to enamel surface preparation protocol, a pretreatment with phosphoric acid in resin-based and polyacrylic acid in glass-ionomers appears to be essential in obtaining the adequate penetration of a sealing material. [ABSTRACT FROM AUTHOR]

This work is part of a larger study whose main objective was to find a series of promising molecules to be used as glass-ionomer-type materials. The project was divided into 3 successive stages; the results of the first stage have been previously published and were used to continue the study. The molecules evaluated in the second stage were constructed by adding a glycidyl methacrylate molecule to the carboxylic groups of the polyacids selected in the previous stage. The modeling was done using the density functional theory for M06-2X/6-311G(d,p). The results indicate that the addition over the carboxylic groups of the fraction of the molecule, corresponding to itaconic acid, is thermodynamically favored. The final stage was modeled with the M06 functional and consisted of obtaining basic structures of glass-ionomer-type materials, by acid–base reaction between the molecules resulting from the second stage with individual ions of Ca (2 +), Zn (2 +), or Al (+ 3). It was concluded that aluminum atoms generate more compact structures that would correlate with more resistant materials. [ABSTRACT FROM AUTHOR]

Background: This study evaluated the ability of a CPP‐ACP‐modified Glass–ionomer cement (GIC) to inhibit demineralization around the margins of cervical cavities in natural teeth in comparison with a Giomer and conventional GIC with and without coating. Methods: Thirty‐two sound human molars were used. Box‐shaped cavities were prepared along the CEJ. Teeth were randomly divided into four groups and restored with Equia Forte Fil, Coated Equia Forte Fil, Fuji VII EP or Beautifil II. Teeth were subjected to pH cycling. Micromorphological and elemental analyses were done using SEM and EDX. Polarized light microscope analysis and microhardness tests were also performed. Results: Microhardness tests on enamel showed a significant difference between the coated Equia group, Equia and Beautifil II groups (P < 0.05). Dentine results showed significant differences between the coated Equia group and all other groups (P < 0.05). Elemental analysis showed significant differences in calcium weight percentage among the first and second observation levels in all groups (P < 0.05). A significant difference was found between the coated Equia group and the other three groups (P < 0.05). Conclusions: All tested materials showed some ability to resist demineralization at the restoration margins. The coated GIC restoration showed better outcomes compared with the other tested materials. [ABSTRACT FROM AUTHOR]

Objective: To explore the long-term in-vivo effect of different dental restorative materials on the surrounding enamel and dentin, in primary molars. Method and Materials: Sixteen naturally exfoliated primary molars restored with amalgam, compomer, and glass-ionomer cement were collected after 2 to 5 years of function in the mouth. Four intact molars served as control. The teeth were sliced buccolingually and the ion content in the restorative material, the enamel, and the dentin surrounding the restoration was determined using a scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDS) program. Results: Amalgam released copper to the enamel and dentin causing a bluish discoloration. No traces of mercury or other ions were detected in the enamel or dentin. The enamel and dentin surrounding the restoration showed reduced inorganic components and increased organic components. The enamel and dentin surrounding the compomer restoration showed similar to amalgam reduction in inorganic components and increased organic components. Traces of fluoride, aluminum, and silicon were found. The enamel and dentin of teeth restored with glass-ionomer cement showed the least reduction in inorganic components, with higher fluoride content and traces of aluminum, silicon, and strontium. Conclusion: This long-term in-vivo study showed release of copper ions from amalgam material to the enamel and dentin, but no traces of mercury. Amalgam and compomers showed no remineralization effect on the dentin surrounding the restoration. Glass-ionomer restorations showed remineralization effect on the tooth components and migration of inorganic ions from the enamel and dentin to the material. [ABSTRACT FROM AUTHOR]

The objective was to evaluate new commercially available ion-releasing restorative materials and compare them to established anti-cariogenic materials. Four materials were tested: alkasite Cention (Ivoclar Vivadent) in self-cure or light-cure mode, giomer Beautifil II (Shofu), conventional glass-ionomer Fuji IX (GC), and resin composite Tetric EvoCeram (Ivoclar Vivadent) as a control. Flexural strength, flexural modulus, and Weibull modulus were measured one day, three months, and after three months with accelerated aging in ethanol. Water sorption and solubility were evaluated for up to one year. Degree of conversion was measured during 120 min for self-cured and light-cured Cention. In this study, Beautifil II was the ion-releasing material with the highest flexural strength and modulus and with the best resistance to aging. Alkasite Cention showed superior mechanical properties to Fuji IX. Weibull analysis showed that the glass-ionomer had the least reliable distribution of mechanical properties with the highest water sorption. The solubility of self-cured alkasite exceeded the permissible values according to ISO 4049. Degree of conversion of light-cured Cention was higher than in self-cure mode. The use of alkasite Cention is recommended only in the light-cure mode. [ABSTRACT FROM AUTHOR]

Background: The effect of the antimicrobial agents benzalkonium chloride (BC) and cetylpyridinium chloride (CPC) on the restorative glass ionomer tooth cement (GIC) Fuji IX was investigated. Aim of the study: The aim of the study was to determine whether the addition of antimicrobial compounds impairs the physical and mechanical properties of the commercial GIC Fuji IX. Materials and Methods: The concentrations of 1%, 2% and 3% of antimicrobial agentsBC and CPC, by weight of the cement, were added during the mixing phase and different effects were studied. In most samples, there was a slight change in setting time. Samples with 4 mm diameter and 6 mm height were used to measure compressive strength and release. The release of antimicrobial compounds was analysed by UV-visible spectrophotometry at a wavelength of 259 nm for CPC and 214 nm for BC, in deionized water. Results: The obtained results showed that the release takes place through the diffusion mechanism in the first 2-3 hours, and the diffusion coefficients vary depending on the concentration. The values range is from 1.97 x 10-14 -1.78 x 10-12 m2 s-1. Release of antimicrobial compound had ceased after seven days, with total release representing between 2.15 and 4.84% of the initial additive loading. Conclusion: Both compounds have minor effect on the setting time of the GIC. The reduction of compressive strength is not statistically significant. CPC containing cements (1 and 2%), were statistically significantly weaker, than those containing BC (p

Objectives. Atraumatic restorative treatment (ART) is a restorative and preventive concept for carious lesions approach. The purpose of this study was to evaluate the durability of ART restorations on temporary molars. Material and method. ART was applied to a group of 64 children aged 4-7 years, with a total number of 112 class I and II carious lesions, located on temporary molars, restored. The material used for coronary restorations by ART technique was Fuji IX glass-ionomer cement (GC Corporation, Tokyo, Japan). Each restoration was evaluated after 6 and 12 months respectively, by code assignment, from 0 to 6. The obtained data were statistically processed using SPSS Version 20.0 (IBM, Chicago, Ill, USA). Results were considered statistically significant for p < 0.05. Results. The 6-month evaluation revealed a high number of scores 0 and 1, without significant differences between them (p > 0.05). Assessment after 12 month revealed a reduction of scores 0 with statistically significant differences in favor of score 1 (p < 0.05). Comparison of the scores of restorations at 6 and 12 months revealed statistically significant differences for score 0 (p < 0.05). Conclusions. The high number of clinically acceptable restorations (scores 0 and 1) underlines the potential of ART to provide for children with an increased degree of anxiety, who have active caries, the treatment of dental lesions.

Background. The effectiveness of fissure sealants in caries prevention depends on their long-term retention and ability to stop caries progression. This randomized controlled clinical trial compared the retention rate and cariostatic properties of a contemporary glass-ionomer-based sealant (GIS) versus a resin-based sealant (RS) placed on fully erupted permanent molars in a split-mouth design. Methods. The sealants were placed on fully erupted permanent teeth (8‒12 years of age) in 45 children. The evaluation was conducted after one week and three and six months. Results. There was a statistically significant difference in the retention rate and caries transition between the two groups over a six-month clinical evaluation period. The resin-based sealant group showed a better retention rate than the GIS group (75.56% and 48.88%, respectively). The resin-based sealant was superior to GIS in preventing caries progression. Conclusion. Resin-based fissure sealant with fluoride releasing properties might be preferable in preventing caries progression of incipient non-cavitated carious lesions in fully-erupted teeth.

Statement of the Problem: The most common cause of endodontic treatment failures is improper coronal sealing. Therefore, besides to proper root sealing, coronal sealing which is supported by a proper restoration has a major role in endodontic treatment success, and coronal microleakage should be considered as an etiologic factor in endodontic treatment failure. Glass-ionomer (GI) has been proposed as a coronal barrier for microleakage after endodontic treatment. Purpose: This study aimed to evaluate the coronal microleakage in GI-obturated root canals in endodontically treated teeth using different thicknesses of GI. Materials and Method: In this in vitro study, forty-five single-rooted extracted human teeth with single canals were collected and disinfected with 0.5% chloramine solution. After endodontic treatment, teeth were divided into 3 groups. In the group 1 to 3, 1 to 3mm of gutta-percha was removed and GI was replaced at 1-, 2- and 3-mm thicknesses respectively. Then subgroups were placed in methylene blue dye and the microleakage was assessed using dye penetration. Results: The mean dye penetration in groups 1, 2 and 3 were 5.1, 3.7 and 2.9, respectively, with statistically significant differences. Group 1 exhibited the highest amount of dye penetration while group 3 showed the least one. Moreover, a significant difference between groups 1 and 2 (p= 0.002) and a non-significant difference between groups 2 and 3 (p= 0.098) was detected in mean dye penetration. Conclusion: Thicker layers of GI might decrease the coronal microleakage. GI at 3-mm thickness resulted in the best protective effect on coronal microleakage in endodontically treated teeth, though further studies are needed to confirm these results.

Aim: To clarify the bond strength of Theracem in comparison to other types of adhesive material, in addition to testing the adhesive remnant index (ARI). Material and Methods: A hundred extracted human premolars were collected for orthodontic purposes. Teeth were stored in 1% Chloramine-T trihydrate as bacteriostatic/bactericidal solution for one week; then, they were transmitted into distilled water. The buccal surface of the studied teeth was kept under surveillance and mounted in acrylic block. Siamese metal preadjusted premolar brackets were fixed on the buccal surface using three adhesive cements: Bisco ORTHO, GC Fuji ORTHO LC (Light Cure) and Theracem. The teeth were randomly divided into five groups of 20 specimens each. Group 1 (G1) used 37% phosphoric acid gel, Bisco primer, and Bisco adhesive. Group 2 (G2) used GC Fuji ORTHO LC (Light Cure) without etching. Group 3 (G3) used GC Fuji ORTHO LC (Light Cure) with etching. Group 4 (G4) used Theracem without etching. Group 5 (G5) used Theracem with etching. All the tested specimens were kept at 370°C in a distilled water bath for 24 h. Shear bond strength (SBS) was conducted using a universal microcomputer-controlled electronic test machine. Then, specimens' surfaces were assessed under a stereomicroscope with a 10× magnification to examine the orthodontics adhesive residue's buccal surface and scored using ARI. Results: The G4 exhibited the lowest mean bond strength value (M = 11.24, SD = 3.52), whereas G3 yielded the highest bond strength value (M = 25.02, SD = 3.41). The variance analysis revealed F = 61.71, indicating a significant difference among the bond strength values (P < .001). Tukey HSD post hoc testing demonstrated a significant difference in bond strength among groups, except G2 with G1 and G3. Kruskal-Wallis test showed statistically significant differences among all groups (P < .001). On comparison, the least adhesives that remained on the tooth surface were in G4 and G5. Conclusion: Theracem bonding system provides many advantages, as there is no need for an acid-etching step, it is easy to manipulate, and it provides a very suitable S.B.S. with no enamel detachment during debonding. Also, scores 0 and 1 in the ARI test lead to a decrease in enamel damage. [ABSTRACT FROM AUTHOR]

Introduction: Coronal microleakage holds importance among various causes of failure after endodontic treatment leading to infection in the periradicular, periodontal ligament, or supporting osseous structures. Loss of coronal seal may occur due to leakage of temporary filling material or fracture of the permanent restoration. Therefore, the use of an intraorifice barrier material would be advantageous in reducing leakage and increasing possibilities for success. Materials and Methods: Fifty single-rooted mandibular premolars were decoronated, cleaned, shaped, and obturated. Gutta-percha was removed to the depth of 3 mm from the orifice. Ten specimens each were sealed with Cention N (Ivoclar Vivadent), Biodentine (Septodont), and glass-ionomer cement (GIC, GC9 high-strength posterior restoration) along with positive and negative control groups, respectively. The teeth were then submerged in dye. Specimens were longitudinally sectioned, and leakage was measured using ×10 stereomicroscope and graded for the depth of microleakage. Results: The samples were subjected to statistical analysis using one-way ANOVA and post hoc Tukey's test and showed that mean microleakage values in all the groups were significantly different from each other (P < 0.001) with the lowest microleakage in Biodentine followed by GIC and Cention N and highest in positive control group. No microleakage was seen in negative control group. Conclusion: The present study concluded that intraorifice barrier placement provides better coronal seal, prevents microleakage, and enhances the longevity of postobturation restorations. Biodentine proved to be the best followed by GIC, Cention N, and control groups.

Aim: The aim of this article is to review the literature on the use of antimicrobial additives in glass-ionomer dental cements. Method: An electronic search between 1987 and the end of 2017 was performed using PubMed, Web of Science and Google search engines with the terms glass-ionomer, glass polyalkenoate, antibacterial and antimicrobial as the key words. The search was refined by excluding the majority of references concerned with cement antimicrobial properties only. Extra papers already known to the authors were added to those considered. Results: A total of 92 relevant articles have been cited in the review of which 55 are specifically concerned with the enhancement of antibacterial properties of glass-ionomers, both conventional and resin-modified, with additives. In addition, information is included on the uses of glass-ionomers and the biological properties of the antibacterial additives employed. There are several reports that show that additives are typically released by diffusion, and that a high proportion is usually left behind, trapped in the cement. Additives generally increase setting times of cements, and reduce mechanical properties. However, smaller amounts of additive have only slight effects and the longer-term durability of cements appears unaffected. Conclusion: Modified glass-ionomer cements seem to be acceptable for clinical use, especially in the Atraumatic Restorative Treatment (ART) technique.

The aim of the study was to assess the choice made by dentists on restoration materials used in the treatment of cavities in temporary teeth and determination of factors that influence their choice. The study was conducted over a period of 6 months on 40 dentists from Iaşi. The evaluation was carried out based on a questionnaire with questions on the type of dental practice (especially if physicians practice predominantly pediatric dentistry), seniority at work, the type of material preferred in the treatment of Black classified cavities. As regards to the type of dental practice, the results of the statistical analysis emphasize that 40% of subjects practice general dentistry and also pediatric dentistry, followed by those who practice only pediatric dentistry (35%). The analysis highlights that 37.5% of physicians use glass ionomer as filing material, 22.5% of them use only composite and 15% use both of them. The results of the study highlight the need for courses and workshops to facilitate the correct choice of restoration materials for temporary teeth cavities.

The aim of this study was to synthesize poly(acrylic acid- co -itaconic acid) (PAA- co -PIA) ionomer through a novel precipitation photopolymerization technique. The ionomer was characterized and the effect of its structural parameters, such as molecular weight and copolymer composition were investigated on the mechanical properties of glass-ionomer prepared using the ionomer. Design of experiment (DOE) was used to examine the effect of monomer ratio and the amount of chain transfer agent on the molecular weight and final conversion of the ionomers synthesized through the precipitation photopolymerization. The copolymer compositions were identified using FTIR and 1H-NMR spectroscopy. The molecular weights of the copolymers were evaluated by GPC. A series of PAA- co -PIA copolymers were then synthesized via the photopolymerization technique in three monomer ratios and two molecular weight ranges (high and low) to study the properties of the glass ionomers thereof. Experimental dental glass-ionomer cements were prepared by mixing the synthesized polymers with glass powder and their compressive properties were determined according to ISO 9917-1:2007 after storing for 0, 1, 7 and 28 days in distilled water. The scanning electron microscopy (SEM) was used to study the fracture surface morphology of the cements. The PAA- co -PIA polymers were synthesized by the photopolymerization method in a short time and high purity. The DOE showed that by decreasing the acrylic acid/itaconic acid ratio and increasing the amount of transfer agent, the molecular weight and final conversion decreased significantly. By increasing the itaconic acid content in the copolymer composition and increasing the molecular weight in a constant copolymer composition, the compressive strength and modulus were increased. Microstructures revealed that cements made of the higher molecular weight poly acids showed lower cracks and voids. The precipitation photopolymerization technique provides a promising and facile method in the synthesis of ionomers which are used in dental cements and other application. [ABSTRACT FROM AUTHOR]

Statement of the Problem: The most common cause of endodontic treatment failures is improper coronal sealing. Therefore, besides to proper root sealing, coronal sealing which is supported by a proper restoration has a major role in endodontic treatment success, and coronal microleakage should be considered as an etiologic factor in endodontic treatment failure. Glass-ionomer (GI) has been proposed as a coronal barrier for microleakage after endodontic treatment. Purpose: This study aimed to evaluate the coronal microleakage in GI-obturated root canals in endodontically treated teeth using different thicknesses of GI. Materials and Method: In this in vitro study, forty-five single-rooted extracted human teeth with single canals were collected and disinfected with 0.5% chloramine solution. After endodontic treatment, teeth were divided into 3 groups. In the group 1 to 3, 1 to 3mm of gutta-percha was removed and GI was replaced at 1-, 2- and 3-mm thicknesses respectively. Then subgroups were placed in methylene blue dye and the microleakage was assessed using dye penetration. Results: The mean dye penetration in groups 1, 2 and 3 were 5.1, 3.7 and 2.9, respectively, with statistically significant differences. Group 1 exhibited the highest amount of dye penetration while group 3 showed the least one. Moreover, a significant difference between groups 1 and 2 (p= 0.002) and a non-significant difference between groups 2 and 3 (p= 0.098) was detected in mean dye penetration. Conclusion: Thicker layers of GI might decrease the coronal microleakage. GI at 3- mm thickness resulted in the best protective effect on coronal microleakage in endodontically treated teeth, though further studies are needed to confirm these results. [ABSTRACT FROM AUTHOR]

Purpose: To estimate the survival of retention of sealant extension to occlusal ART restorations over 6.3 years; and to test the null-hypothesis that there is no difference in dentine caries lesion development in sealant extension to ART restorations in comparison with sealant free extensions to amalgam restorations in occlusal surfaces over 6.3 years.Materials and Methods: In a parallel group design, 318 and 254 grade 2 children were randomly assigned to the ART and amalgam group respectively. Eight dentists placed 925 evaluatable single- and multiple-surfaces restorations. A total of 424 sealed extensions to occlusal ART and 284 sealant free extensions to occlusal amalgam restorations were available for analyses. The modified actuarial method was used to estimate survival percentages. The jackknife method was applied to calculate the SE in the cumulative survival percentages.Results: After 6.3 years, 11.2% (SE = 2.2%) of sealant extensions were fully retained and 16.7% (SE = 2.8%) were partially retained. After 6.3 years, 86.4% (SE = 2.2%) of the sealed pits and fissures adjacent to occlusal ART restorations and 89.9% (SE = 2.4%) of non-sealed pits and fissures adjacent to occlusal amalgam restorations were free of dentine caries lesions. Neither this difference nor those at earlier evaluation years were statistically significant (p > 0.05).Conclusion: Sealing pits and fissures adjacent to occlusal ART restorations did not result in a caries preventive benefit over non-sealed pits and fissures adjacent to occlusal amalgam restorations in this group of children over 6.3 years. [ABSTRACT FROM AUTHOR]

Statement of problem: Hardness of restorative materials like glass-ionomer is an important factor in the longevity of restoration. Objectives: The aim of this study was to evaluate the microhardness of glass-ionomer modified with different materials. Materials and Methods: Sixty disk-shaped specimens were examined in six groups in this study, including conventional glass-ionomer (Shofu, Japan), zirconia-reinforced glass-ionomer (Zirconomer, Shofu, Kyoto, Japan), silver-reinforced glass-ionomer (HI-DENSE XP, Shofu, Kyoto, Japan) and mixture of these three types of glass-ionomer with 20 wt% of microhydroxyapatite (Sigma-Aldrich, St. Louis, USA). All the specimens were stored in deionized water for 24 hours. Then Vickers microhardness test was carried out and the results were analyzed by using two-way ANOVA test and paired t-test (P

The effect of aqueous hydrogen sulfide on the properties of a conventional and a resin-modified glass-ionomer dental cement has been determined. Specimens were stored for 1 week in (i) H₂S/glycerol/water, (ii) glycerol/water and (iii) pure water. After this time, the mass changes were determined, the pH of the solution was measured and the ion-content was determined, the latter by ICP-OES. There were significant differences in the mass uptake, pH change and ion release of the cements. Both showed significant gains in mass in both water and water/glycerol. In H₂S /water/glycerol Ketac Cem (a conventional glass-ionomer) showed an insignificant mass loss, and Fuji Plus showed a minor significant gain. Both materials altered the pH of all storage solutions significantly. The pH of the H₂S /water/glycerol medium increased whereas the pH of both pure water and water/glycerol went down. The ion release into glycerol/water was different from release into water, with sodium release being suppressed. The H₂S medium showed almost no differences from glycerol/water, indicating that the H₂S component has almost no effect on these cements. This leads to the conclusion that these cements can safely be used sub-gingivally even in patients where oral malodour suggests that reasonable amounts of H₂S may be present.

Background: Despite the superiority of glass-ionomer cements (GICs) over composites in treating white spot lesions (WSLs), there is still a concern about their preventive and antibacterial properties. Efforts have been made to improve the strength of their bond to demineralized enamel, fluoride release and antibacterial properties by adding nanoparticles of chitosan, which seems to be a promising method., Objectives: The aim of the present study was to assess the antibacterial effect, the microshear bond strength (μSBS) to enamel at the WSL area, and the fluoride and nano-chitosan release after modifying the polyacrylic acid liquid phase of a traditional GIC with different nano-chitosan volumes., Material and Methods: A total of 120 samples were prepared, and then divided into 4 groups (n = 30): G1 - non-modified GIC, which served as a control group, while G2, G3 and G4 were modified with different nano-chitosan volumes (50%, 100% and 150%, respectively). Microshear bond strength was assessed using a universal testing machine (UTM) after storage in distilled water for 24 h. Fluoride and nanochitosan release was measured with the use of spectrophotometers at different time points (initially, and at 1 h, 24 h, 48 h, 72 h, 1 week, 2 weeks, 3 weeks, and 6 weeks) after storage in distilled water. The antibacterial effect against the Streptococcus aureus strain was assessed with the agar diffusion test. The data was statistically analyzed., Results: After 24-hour storage, G2 recorded a slight, yet non-significant, increase in the μSBS values (4.1 ±0.94 MPa) as compared to G1 (3.9 ±1.30 MPa). With regard to fluoride release, the amount recorded for G1 was significantly greater at the end of the 24-hour storage period (0.70 ±0.30 μmf/cm2) than modified nano-chitosan GIC groups; G1 was followed by G4 (0.54 ±0.34 μmf/cm2). The highest amount of nano-chitosan release after 24-hour storage was noted for G3 (0.85 ±0.00 μmf/cm2). The highest inhibition zone value was recorded for G2., Conclusions: Glass-ionomer cement modified with 50% nano-chitosan was shown to positively affect μSBS and the antibacterial effect, while modification with 150% nano-chitosan significantly increased fluoride release.

To determine the effect of storage temperature and the presence of sodium chloride in solution on the fluoride uptake and release of glass-ionomer cements. Several commercial brands were used, and stored at either room temperature (21–23 °C) or 37 °C, in KF solution at a concentration of 1000 ppm F− with and without 0.9% NaCl present. Fluoride levels in the storage solutions after 24 h were measured using a fluoride-ion selective electrode. Specimens were then stored in water, and fluoride release after 24 h was determined. Studies were also carried out to determine chloride levels when specimens were stored in 0.9% NaCl, with or without 1000 ppm fluoride, again using an ion selective electrode. All glass-ionomer specimens took up fluoride, and most of the fluoride was retained over the next 24 h when the specimens were stored in water. There was a slight variation in the amount of fluoride taken up with storage temperature and with the presence of sodium chloride. All specimens also took up chloride, with greater uptake at higher temperatures, but little or no effect when KF was also present in solution. The substantial retention of fluoride after 24 h in deionised water confirms previous findings and suggests that an insoluble species, possibly SrF 2 , forms in situ. Chloride uptake has not been reported previously, and its significance requires further investigation. Fluoride and chloride uptake were apparently independent of each other, which suggests that the ions are taken up at different sites in the cement. This may relate to differences in the respective sizes and hydration states of F− and Cl− ions. [ABSTRACT FROM AUTHOR]

Background. The effectiveness of fissure sealants in caries prevention depends on their long-term retention and ability to stop caries progression. This randomized controlled clinical trial compared the retention rate and cariostatic properties of a contemporary glass-ionomer-based sealant (GIS) versus a resin-based sealant (RS) placed on fully erupted permanent molars in a split-mouth design. Methods. The sealants were placed on fully erupted permanent teeth (8.12 years of age) in 45 children. The evaluation was conducted after one week and three and six months. Results. There was a statistically significant difference in the retention rate and caries transition between the two groups over a six-month clinical evaluation period. The resin-based sealant group showed a better retention rate than the GIS group (75.56% and 48.88%, respectively). The resin-based sealant was superior to GIS in preventing caries progression. Conclusion. Resin-based fissure sealant with fluoride releasing properties might be preferable in preventing caries progression of incipient non-cavitated carious lesions in fully-erupted teeth. [ABSTRACT FROM AUTHOR]

Background and objective: Besides hand-mixed formulations, glass-ionomer restorative materials are also available in sealed capsules. The main advantage of capsulated materials is that clinicians cannot alter the powder/liquid ratio. This research was conducted to investigate the consistency of the recommended powder/liquid ratio by the manufacturer in relation to the actual content of the capsule and to determine whether these variations from the manufacturers' recommendations have any influence on the surface microhardness and compressive strength. Methods: Two different batch numbers for five glass-ionomer restorative materials and one Carbomer were evaluated. Twenty specimens were selected from each batch of materials: Chemfil Rock (Dentsply Sirona), Fuji Equa Forte (GC Corp), Glass Fill (GCP dental), lonofil Molar AC (Voco) and Ketac Universal (3M ESPE) and Riva Self Cure (SDI Limited). The capsules were deconstructed and the powder and liquid were weighed. Additionally, five specimens were prepared for each time interval (days 1, 7 and 180) and the compressive strength assessed. The surface microhardness (Vickers hardness) was completed on five specimens per batch and assessed sequentially at days 1, 7 and 180 on the same specimen after the elapsed time intervals. Results: The results showed that there were significant differences between the two batches for the powder and liquid content for Chemfil Rock (p<0.001), Ketac Universal (p=0.029) and Riva Self Cure (p<0.001). There were no significant differences for surface micro-hardness or compressive strength between the two batches for any of the assessed time intervals (days 1, 7 and 180). Conclusion: There were differences between the various batches from the same manufacturer concerning the powder/liquid ratio content. The actual content of powder and liquid from the two batches differed when compared to the manufacturers' recommended powder/liquid ratio on the package insert for most of the manufacturers. The difference in powder/liquid ratios between batches did not significantly influence the Vickers hardness or the compressive strength for the material over the same time period. [ABSTRACT FROM AUTHOR]

Aim: The aim of this article is to review the literature on the use of antimicrobial additives in glass-ionomer dental cements. Method: An electronic search between 1987 and the end of 2017 was performed using PubMed, Web of Science and Google search engines with the terms glass-ionomer, glass polyalkenoate, antibacterial and antimicrobial as the key words. The search was refined by excluding the majority of references concerned with cement antimicrobial properties only. Extra papers already known to the authors were added to those considered. Results: A total of 92 relevant articles have been cited in the review of which 55 are specifically concerned with the enhancement of antibacterial properties of glass-ionomers, both conventional and resin-modified, with additives. In addition, information is included on the uses of glass-ionomers and the biological properties of the antibacterial additives employed. There are several reports that show that additives are typically released by diffusion, and that a high proportion is usually left behind, trapped in the cement. Additives generally increase setting times of cements, and reduce mechanical properties. However, smaller amounts of additive have only slight effects and the longer-term durability of cements appears unaffected. Conclusion: Modified glass-ionomer cements seem to be acceptable for clinical use, especially in the Atraumatic Restorative Treatment (ART) technique. [ABSTRACT FROM AUTHOR]

This study determined the influence of coating with either petroleum jelly or light-cured varnish and storage medium on the flexural strength of glass-ionomer cements (GIC). The flexural strength of two glass-ionomer cements (Fuji Equia Fil and Ketac Molar Aplicap) was measured. Specimens (2 × 2 × 25 mm) were prepared in three groups: uncoated, coated with petroleum jelly, or coated with light-cured varnish (EquiaCoat) cured for 20 s using a cure lamp (Bluephase G2, Ivoclar Vivadent, Schaan, Liechtenstein). Specimens were stored for 1 week at 37 °C in water, artificial saliva or 20 mmol dm−3 lactic acid, then flexural strength was determined in 3-pont bend. Data were analyzed by ANOVA and Tukey HSD post hoc test (p

Abstract The addition of charged polymers, like poly-aspartic acid (pAsp), to mineralizing solutions allows for transport of calcium and phosphate ions into the lumen of collagen fibrils and subsequent crystallization of oriented apatite crystals by the so-called Polymer-Induced Liquid Precursor (PILP) mineralization process, leading to the functional recovery of artificial dentin lesions by intrafibrillar mineralization of collagen. Objective To evaluate the feasibility of applying the PILP method as part of a restorative treatment and test for effectiveness to functionally remineralize artificial lesions in dentin. Materials and Methods Two methods of providing pAsp to standardized artificial lesions during a restorative procedure were applied: (A) pAsp was mixed into commercial RMGI (resin modified glass ionomer) cement formulations and (B) pAsp was added at high concentration (25 mg/ml) in solution to rehydrate lesions before restoring with a RMGI cement. All specimens were immersed in simulated body fluid for two weeks to allow for remineralization and then analyzed for dehydration shrinkage, integrity of cement-dentin interface, degree of mineralization, and changes in the nanomechanical profile (E-modulus) across the lesion. Results After the remineralization treatment, lesion shrinkage was significantly reduced for all treatment groups compared to demineralized samples. Pores developed in RMGI when pAsp was added. A thin layer at the dentin-cement interface, rich in polymer formed possibly from a reaction between pAsp and the RMGI. When analyzed by SEM under vacuum, most lesions delaminated from the cement interface. EDS-analysis showed some but not full recovery of calcium and phosphorous levels for treatment groups that involved pAsp. Nanoindentations placed across the interface indicated improvement for RMGI containing 40% pAsp, and were significantly elevated when lesions were rehydrated with pAsp before being restored with RMGI. In particular the most demineralized outer zone recovered substantially in the elastic modulus, suggesting that functional remineralization has been initiated by pAsp delivery upon rehydration of air-dried demineralized dentin. In contrast, the effectiveness of the RMGI on functional remineralization of dentin was minimal when pAsp was absent. Significance Incorporation of pAsp into restorative treatments using RMGIs promises to be a feasible way to induce the PILP-mineralization process in a clinical setting and to repair the structure and properties of dentin damaged by the caries process. [ABSTRACT FROM AUTHOR]

Introduction: Coronal microleakage holds importance among various causes of failure after endodontic treatment leading to infection in the periradicular, periodontal ligament, or supporting osseous structures. Loss of coronal seal may occur due to leakage of temporary filling material or fracture of the permanent restoration. Therefore, the use of an intraorifice barrier material would be advantageous in reducing leakage and increasing possibilities for success. Materials and Methods: Fifty single-rooted mandibular premolars were decoronated, cleaned, shaped, and obturated. Gutta-percha was removed to the depth of 3 mm from the orifice. Ten specimens each were sealed with Cention N (Ivoclar Vivadent), Biodentine (Septodont), and glass-ionomer cement (GIC, GC9 high-strength posterior restoration) along with positive and negative control groups, respectively. The teeth were then submerged in dye. Specimens were longitudinally sectioned, and leakage was measured using ×10 stereomicroscope and graded for the depth of microleakage. Results: The samples were subjected to statistical analysis using one-way ANOVA and post hoc Tukey's test and showed that mean microleakage values in all the groups were significantly different from each other (P < 0.001) with the lowest microleakage in Biodentine followed by GIC and Cention N and highest in positive control group. No microleakage was seen in negative control group. Conclusion: The present study concluded that intraorifice barrier placement provides better coronal seal, prevents microleakage, and enhances the longevity of postobturation restorations. Biodentine proved to be the best followed by GIC, Cention N, and control groups. [ABSTRACT FROM AUTHOR]

Aim: To test the hypothesis that polyacrylic acid‐based and calcium silicate materials are able to increase mineral density of artificially demineralized dentine produced by a microcosm model for caries formation. Methodology: Forty‐five dentine cavities were prepared in nine sound human third molars (five in each tooth). Specimens received a bacterial inoculum and were incubated in BHI plus 5% of sucrose for 96 h to allow biofilm formation. After that, the specimens were scanned in a high energy micro‐CT (baseline stack) and then, each cavity was filled with different cements: zinc polycarboxylate (Poly Zinc™, Prevest DenPro, Jammu, India), conventional glass–ionomer (Ketac Molar, 3M ESPE, Seefeld, Germany) and two calcium silicate‐based materials (MTA, Angelus, Londrina, Brazil and Biodentine™, Septodont, Saint Maur des Fosses, France) whilst the central cavity was filled with utility wax (negative control). Specimens were kept for 45 days under simulated intrapulpal pressure using simulated body fluid and after, they were again scanned (treated stacks). Reconstruction of the acquired projections was accomplished using standardized parameters, and the percentage mineral density change was calculated around each cavity. Data were tested for normality using the Shapiro–Wilk test, followed by nonparametric methods. Results: A microcosm artificial caries model was able to cause dentine demineralization (±90% related to sound dentine). Significant increases in dentine mineral density were achieved using MTA or Poly Zinc™ (43.56% and 41.64% remineralization), followed by Biodentine™ (36.40%) and Ketac Molar (32.54%), P < 0.05. Conclusion: All cements increased mineral density in demineralized dentine, but zinc polycarboxylate cement and MTA had greater bioactive potential. Micro‐CT proved to be an effective method to evaluate changes in mineral density within dentine in contact with bioactive materials. [ABSTRACT FROM AUTHOR]

Purpose: Teeth caries is one of predominant civilization diseases. Dental fillings with antimicrobial addition might allow prevention of secondary caries. The purpose of this study was to evaluate hardness and tensile strength of cetylpyridinium chloride modified water activated glass-ionomer cement. Methods: Samples with diameter of 6 mm and height of 3 mm made of water-activated glass-ionomer cement were control group (0.0%). Test groups were series of samples of the same dimensions, with addition of cetylpyridinium chloride antimicrobial in concentrations of 0.5, 1.0, 1.5 and 2.0%. Two subgroups were prepared in each group to determine Vickers Hardness and Diametral Tensile Strength after 1 and 24 hours of sample storage in distilled water. Results: During hardness studies, no strong effect of antimicrobial concentration on hardness of samples was observed. Higher hardness values after 24 hours were demonstrated for all groups, compared to the samples tested after 1 hour. The exception was the group with the addition of 1% cetylpyridinium chloride, in which no statistically significant differences were observed. Diametral Tensile Strength values for samples tested after 1 hour decreased with increasing antibacterial concentration. A similar relationship was noticed for samples tested after 24 hours. No statistically significant differences were found between test samples after 1 or 24 hours. Conclusions: There was no significant effect of cetylpyridinium chloride concentration on the hardness of the samples that significantly increased during the study. With the increase in antimicrobial concentration a decrease in diametral tensile strength value was observed, but these values did not change over time. [ABSTRACT FROM AUTHOR]

Phosphorus elution from four commercial brands of glass-ionomer dental cement has been studied. Release was found to be linear with time up to 14 days in both neutral and acid conditions, indicating that release occurs by dissolution rather than by diffusion. Release was substantially greater in acidic conditions than neutral ones. The species released were studied by ion chromatography, and all brands showed clear release of the monomeric species orthophosphate PO4 3-. Attempts to confirm this using 31P NMR spectroscopy were generally unsuccessful due to the relatively high detection limit in NMR, but for the neutral solution derived from the brand Chemflex, a weak signal was observed at 1.64 ppm, which confirmed the occurrence of orthophosphate. In addition, an unidentified species was released by all brands except Fuji IX, and this has been tentatively identified as mono-fluorophosphate PO3F2-. It is suggested that the release of these phosphate species may be beneficial in promoting remineralization when these cements are used clinically

This article reviews some of the merging ethical issues in restorative dentistry. This is a branch of healthcare concerned with quality of life, since retention of functioning teeth is important in allowing a healthy diet to be consumed. Yet the supply of dentists is such that, in many of the world’s poorest countries, extraction is the only viable option for treating tooth decay. Available repair materials present various ethical problems. Silver amalgam is being phased out in much of the world, because of environmental concerns with mercury, yet it is cheap and reliable. Alternatives have been developed, influenced by the West’s preoccupation with appearance, yet these materials are difficult to place and are less durable than amalgam. These concerns lead to significant ethical problems, which are explored in this article. It concludes by proposing a way to deal with the emerging ethical problems. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to evaluate and compare the retentive strength of orthodontic bands cemented with amorphous calcium phosphate (ACP)-containing and conventional glass ionomer cements (GICs). Materials and Methods: One-hundred-and-twenty mandibular third molars were embedded in acrylic resin blocks with the buccal surface of crowns perpendicular to the base of the mold. The teeth were randomly divided into four groups containing 30 teeth each. Groups 1 and 3 were cemented using conventional GIC and groups 2 and 4 were cemented using ACP-containing orthodontic cement. Groups 1 and 2 without thermocycling, and groups 3 and 4 after thermocycling (5000 cycles, 5° to 55°C) were tested for retentive strength using a universal testing machine (crosshead speed of 1mm/minute). Two-way ANOVA was performed to compare the retentive strength of the groups. Results: The highest retentive strength belonged to group 1, and it was significantly higher than that of group 2 (P

Materials used in the body, especially the materials used in various oral cavity regions should be stable and passive without any interactions with the body tissues or fluids. Dental amalgam, composite resins and dental cements are the materials of choice with such properties. The first attempts to produce active materials, which could interact with the human body tissues and fluids were prompted by the concept that fluoride-releasing materials exert useful effects in the body. The concept of using the "smart" materials in dentistry has attracted a lot of attention in recent years. Conventional glass-ionomer (GI) cements have a large number of applications in dentistry. They are biocompatible with the dental pulp to some extent. GI is predominantly used as cements in dentistry; however, they have some disadvantages, the most important of which is lack of adequate strength and toughness. In an attempt to improve the mechanical properties of the conventional GI, resin-modified glass-ionomers have been marketed, with hydrophilic monomers, such as hydroxyethyl methacrylated (HEMA). Some recent studies have evaluated GI with bioactive glass in its structure to validate the claims that such a combination will improve tooth bioactivity, regeneration capacity and restoration. There is ever-increasing interest in the application of bioactive materials in the dental field in an attempt to remineralize affected dentin. The aim of this review article is to evaluate these materials and their characteristics and applications.

Adhesive technology has evolved rapidly since it was introduced more than fifty years ago. Today, decayed or fractured teeth can be reconstructed minimally invasively and nearly invisibly using adhesive technology. However, the clinical longevity is sometimes still too short. Although water sorption is thought to be the main destabilizer of the biomaterial–tooth bond, the actual interfacial degradation mechanisms are far from understood. The fundamental mechanism of bonding to enamel and dentin is essentially based on an exchange process, in which minerals removed from the dental hard tissues are replaced by resin monomers that upon polymerization become micro-mechanically interlocked in the created porosities. In addition to micro-mechanical interlocking through hybridization, the potential benefit of additional chemical interaction between functional monomers/polymers and tooth substrate components has recently regained attention. In this review paper, we focus on how chemical interaction at the biomaterial–hard tissue interface can improve bond durability.

Introduction: A coronal barrier in root-filled teeth is one of the most effective methods for prevention of coronal microleakage. The aim of this study was to compare coronal microleakage of three materials [light-cured glass-ionomer (GI), mineral trioxide aggregate (MTA), and composite resin] as coronal barriers. Materials and Methods: A total of 188 intact maxillary incisors were used. After instrumentation, all the canals were obturated with gutta-percha and lateral condensation technique using AH26 sealer. Then, the teeth were sectioned just apical to the cemento-enamel junction. The roots were randomly assigned to three experimental groups (n=56) and two negative and positive control groups (n=20). After placing the orifice barrier, the samples were immersed in 2% methylene blue solution for 2 weeks at 37°C. Then the teeth were longitudinally sectioned mesiodistally and dye penetration was measured under a stereomicroscope at ×10 magnification. Data were analyzed with one-way ANOVA and a post-hoc Tukey test. Results: The positive control group leaked significantly more than all the experimental groups (P=0.001). MTA exhibited less leakage than composite and GI (P=0.002) but no significant differences were found between GI and composite groups. Conclusion: Immediate placement of a suitable intra-orifice barrier like MTA, before final restoration, may help minimize recontamination of the remaining apical gutta-percha.

The purpose of this study was the OM = optical microscopy analysis of the dentinal HL=hybrid layer of two materials with metal alloy particles used in minimally invasive cavity preparations. The study included 10 human premolars and molars, extracted for orthodontic or periodontal reasons. The extracted teeth were used in the study after obtaining a informed consent from the patients, in compliance with the protocol approved by the ethics committee of UMF Gr.T.Popa Iasi. Samples were divided randomly into two equal groups (N = 5): GR.1 (N = 5), GR2 (N = 5). Minimally invasive occlusal cavities were made using a mechanical preparation. We used cylindrical diamond burrs and carbide globular no. 1 burrs. The restorative materials used were: PAA=PolyAcrylic Acid, SE = 3M ™ Scotchbond Etch ™, dental adhesive ASBP = Adper Single Bond Plus (3M ESPE), glass-ionomer with metal alloy particles MM = MIRACLE MIX (3M ESPE) and non gamma 2 amalgam A=ANA2000. The analyzed groups were: GR.1:(5)PAA;MM and GR.2:(5)SE™;ASBP;A. Materials were used according to the manufacturer’s instructions, the resulting samples were thermo cycled 500 cycles (5 0 -55 0), sectioned, viewed by OM=ZEISS–AXIO-CAM-MRC5 and statistically analysed (ANOVA, p ≤ 0.05). Statistical data processing was performed with Microsoft Excel and SPSS 14.0, p ≤ 0, 05. The results obtained by quantitative analysis of the HL indicate that there are differences (p ≤ 0.05) between groups in favour of the samples filled with amalgam 10.37 (± 2.62). Conclusions: The restoration material and the use of a dentinal adhesive dimensionally influence the HL size

One of the most efficient prophylactic measures in caries prevention is sealing pits and fissures. After improvements of physical and mechanical properties, glass-ionomers are frequently used as sealing materials. The aim of this study was to evaluate the prophylactic efficiency of Fuji VII, a glass-ionomer fissure sealant, through adaptation ability and fluoride reeasing potential assessment using scanning electron microscopic and energy dispersive spectroscopic techniques. The sample consisted of 20 extracted intact human teeth, 10 premolars and 10 molars. Six sections of each tooth were analyzed using SEM. EDS analysis was conducted one week and three months after material placement. The parameters used for the evaluation included: adaptation ability, penetration depth, material structure, integrity of the interfacial zone and ion exchange extent. The sealant penetration depth was observed at 30 X magnification, and the interfacial zone between the material and the enamel at 500-10000 X. EDS was used for quantitative analysis of the material structure, interfacial zone and the enamel surface. The results were statistically analyzed the using chisquare test and descriptive statistical methods. SEM analysis revealed the zone of interaction between the enamel surface and the glass-ionomer with predominant cohesive failures within the sealant material, and satisfactory adaptation ability of the sealing material. The mean value of the penetration was 83% of the total fissure depth, without a statistically significant difference between the tested teeth groups. A lower penetration ability was observed in deep pits and fissures with a larger diameter of unfilled space (p

This study determined the influence of coating with either petroleum jelly or light-cured varnish and storage medium on the flexural strength of glass-ionomer cements (GIC). The flexural strength of two glass-ionomer cements (Fuji Equia Fil and Ketac Molar Aplicap) was measured. Specimens (2 × 2 × 25 mm) were prepared in three groups: uncoated, coated with petroleum jelly, or coated with light-cured varnish (EquiaCoat) cured for 20 s using a cure lamp (Bluephase G2, Ivoclar Vivadent, Schaan, Liechtenstein). Specimens were stored for 1 week at 37 °C in water, artificial saliva or 20 mmol dm−3lactic acid, then flexural strength was determined in 3-pont bend. Data were analyzed by ANOVA and Tukey HSDpost hoctest (p < 0.05). In addition, the mold was filled with water and the temperature change caused by the cure lamp was measured with a thermocouple. For both materials, storage in water gave the lowest flexural strength. It was slightly higher in either saliva or lactic acid, and was improved by coating in petroleum jelly. Specimens coated with light-cured varnish, that also involved heating with a cure lamp, gave the highest flexural strength. The heating effect of the lamp was demonstrated by the temperature rise in the water in the mold after light exposure from 21.9 (± 1.0) °C to 26.8 (± 1.0) °C. hence, sealing of GIC from aqueous media improves flexural strength. The cure lamp emitted heat, which may enhance the flexural strength of specimens coated with light-cured varnish. [ABSTRACT FROM AUTHOR]

Objective: Removal of enamel superficial layer during microabrasion treatments may adversely affect sealing ability of the restorative materials. The aim of this study was to measure the effect of different periods of enamel microabrasion on the microleakage of class V glass-ionomer restorations. Methods: This in vitro experimental study was conducted on 96 Class V cavities which had been prepared on the buccal and lingual surfaces of 48 sound human premolars. After conditioning with 10% polyacrylic acid (GC, Tokyo, Japan) one half of the cavities were restored with the conventional glass-ionomer (Fuji II GC, Tokyo, Japan) and another half with resin-modified glassionomer (Fuji II LC GC, Tokyo, Japan). Finishing and polishing were performed after 24 hours and the teeth incubated for 2 weeks (37°C and 100% humidity).Then the teeth were classified into eight groups (n=12). Microabrasion treatment was performed with Opulster (Ultradent product Inc, South Jordan, UT, USA) in 0(control no treatment), 60, 120 and 180 seconds. Then teeth were thermocycled between 5°C-55°C (×1000), immersed in 0.5% basic-fushin solution (24h) and sectioned longitudinally in bucco-lingual direction (n=192). Dye penetration was examined with stereomicroscope (×40). Microleakage scores were statistically analyzed by Kruskal-Wallis test while the paired comparisons were done using Mann-Whitney U test. Results: The mean microleakage scores were significantly increased following increased microabrasion times in occlusal margin in FU II (p<0.009) and FU II LC (p<0.02) and in gingival margin in resin-modified glass-ionomer (p<0.04). Conclusion: In Fuji II restorations after microabrasion in occlusal margins, microleakage increased up to 120s but in gingival margins no significant difference were seen. In Fuji II LC restorations after microabrasion in occlusal margin, microleakage from 60s up to 180s was significantly increased. In gingival margin with increasing the time up to 180s microleakage increased. [ABSTRACT FROM AUTHOR]

This study evaluated the fracture resistance of endodontically treated teeth restored with different base materials and mesioocclusal- distal (MOD) ceramic inlays. Fifty mandibular molars were assigned into five groups (n=10 per group). Group1 (control) comprised intact molar teeth without any treatment. Teeth in other groups were subjected to root canal treatment and restored with MOD ceramic inlays on different base materials. In Group 2, base material was zinc phosphate cement; Group 3's was glass ionomer cement; Group 4's was composite resin, and Group 5's was composite resin reinforced with fiber. Finally, a continuous occlusal load was applied until fracture occurred. Mean fracture resistance of Group 1 (3,027 N) was significantly higher than the other groups (890, 1,070, 1,670, 1,226 N respectively). Fracture resistance of Group 4 was statistically comparable with Group 5 and significantly higher than Groups 2 and 3 (p<0.05; Tukey's HSD). Use of different base materials under ceramic inlay restorations could affect the fracture resistance of endodontically treated teeth. [ABSTRACT FROM AUTHOR]

Objective To determine the shear bond strength (SBS) between synthetic controlled porous hydroxyapatite (HAP) inserts and restorative materials and dimensional changes of insert-containing restorations during curing. Methods Cylinder-shaped HAP inserts (4 mm in diameter, 1.6 mm thick) were cemented in dentin discs (5 mm × 1.6 mm), cut mid-coronally from human third molars, using one of the following materials: universal microhybrid composite Filtek Z250, flowable composite Filtek Ultimate or glass-ionomer Vitrebond (all 3M ESPE). SBS of the same materials to HAP inserts was tested in a universal testing machine. Three-dimensional digital image correlation system Aramis (GOM) was used to measure strains and displacements. Data were statistically analyzed using one-way ANOVA with Tukey's post-test ( α = 0.05). Results SBS of restorative materials to HAP inserts ranged between 12.2 ± 2.1 MPa (Filtek Z250) and 0.7 ± 0.4 MPa (Filtek Z250 without an adhesive). The ‘total-etch’ approach of adhesive application significantly increased SBS of both Filtek Z250 (12.2 ± 2.1 MPa) and Filtek Ultimate flowable (9.5 ± 2.5 MPa) compared to the ‘self-etch’ approach (8.2 ± 1.6 MPa and 4.4 ± 0.9 MPa, respectively) ( p < 0.05). HAP inserts reduced polymerization shrinkage to below 0.5% as well as displacements in the central region of the restorations. Peripheral shrinkage of restorative materials was similar with and without HAP inserts as were displacements of Filtek Z250 and Vitrebond. Significance Replacing major part of dentin clinically, especially in large cavities, HAP inserts may shorten clinical working time, improve dimensional stability of the restoration by reducing central shrinkage and displacements and provide adhesive bonding to universal composites following a ‘total-etch’ approach. [ABSTRACT FROM AUTHOR]

The thermal characteristics of four conventional glass-ionomer cement (GIC) dental restorative products as well as five resin-modified glass-ionomer (RMGI) materials over 1-year of storage were investigated. All materials were prepared following manufacturer's recommendations and placed into 40 μL aluminum differential scanning calorimeter (DSC) crucibles. Samples ( n = 5) were stored at 37 °C and 98 ± 2 % humidity until their appointed time of evaluation at which they were first subjected to specific heat analysis using DSC over 20-60 °C that was immediately followed by a 37-600 °C thermal scan at 10 °C min. Samples were evaluated immediately after preparation, at 24 h, 1 week, 1 month, as well as at 3, 6, 9, and 12 months. Mean thermal results were compared with analysis of variance and Scheffe post-hoc testing ( p = 0.05). All materials absorbed water during storage. Conventional GIC materials demonstrated increased polyalkenoate polymer maturity over the 12-month storage. The paste-paste RMGI materials, absorbed more water during storage and had increased specific heat values compared to powder-liquid RMGI materials. Of the RMGI materials investigated, only two materials demonstrated evidence of a continuing polyalkenoate matrix maturity that was within the limitations of the technology used, indicating the resin component in some newer formulations of RMGI restorative materials may severely limit the polyalkenoate reaction. [ABSTRACT FROM AUTHOR]