The marginal seal of Class II restorations: flowable composite resin compared to injectable glass ionomer

The objective of this study was to investigate the effect of a flowable composite resin (Tetric Flow) versus an injectable glass ionomer (Fuji II LC) on microleakage at the cavosurface margin of the proximal box of Class II restorations in permanent teeth in-vitro. Thirty caries and restoration-free human bicuspids were prepared with mesial and distal slot preparations and were filled either with a bonding agent (Optibond) plus a flowable composite resin (Tetric Flow), Group I; bonding agent (Optibond) plus a flowable glass ionomer (Fuji II LC), Group II; or a flowable glass ionomer (Fuji II LC) with no bonding agent, Group III. All specimens were then immersed in a 2% solution of basic fuschin dye for 24 hours to allow for dye penetration into possible existing gaps. These teeth were then carefully sectioned mesially/distally into two pieces using an Isomet saw. The teeth were then studied under a binocular microscope to measure depths of dye penetrations as an indication of marginal microleakage at the gingival cavosurface margin and scored as follows: 0 = no dye penetration, 1 = dye penetration into enamel only, 2 = dye penetration into enamel and dentin, 3 = dye penetration into the pulp. The specimens were also evaluated using a SEM. The results showed that there were statistically significant differences between Groups I (Tetric Flow) and (Fuji II LC plus bonding agent), II in favor of Group I; between Groups I and (Fuji II LC with no bonding agent), III in favor of Group I; as well as Groups II and III in favor of Group II (Fuji II LC plus bonding agent). Group I (bonding agent plus flowable composite resin) showed significantly less microleakage. Group II (bonding agent plus flowable glass ionomer) demonstrated a bond that existed between the bonding agent and the glass ionomer but microleakage within microgaps of the glass ionomer itself Group III (flowable glass ionomer plus no bonding agent) demonstrated significant microleakage between the glass ionomer and tooth structure, microgaps within the glass ionomer, and lack of retention of the restoration. It appears that the use of a flowable composite resin (Tetric Flow) plus a bonding agent (Optibond) in the proximal box of a Class II restoration in permanent teeth will significantly reduce the microleakage at the cavosurface margin when compared with an injectable glass ionomer (Fuji II LC) with or without a bonding agent (Optibond).     

Bacterial microleakage of barrier materials in obturated root canals

The bacterial microleakage of four current restorative materials (glass ionomer cement, polycarboxylate cement, resin modified glass ionomer cement, and flowable composite resin) used as a base over obturated root canals were evaluated during a 5-month period. Sixty single-rooted mandibular premolars were obturated with cold lateral compaction of gutta-percha. The teeth were randomly divided into five groups of 10 teeth each and positive and negative control groups of five. The access openings were filled with one of the tested barrier materials in four groups. In group 5, no barrier material was placed. Samples were incorporated in a model system using Staphylococcus epidermidis as a microbial marker. Results were analyzed with Kaplan-Meier survival analysis (p = 0.05). The sealing ability of all tested materials was better when compared with group 5 (no barrier material) (p < 0.05). Within the limitations of this study, the glass ionomer cement leaked significantly less when compared with the flowable composite resin (p < 0.05).     

Postoperative dental bleaching: effect of microleakage on Class V tooth colored restorative materials

The effect of 3 percent, 11 percent, and 16 percent carbamide peroxide bleaching solutions and 35 percent hydrogen peroxide bleaching gel on microleakage of Class V composite resins, resin modified glass ionomer cements, and compomer restorative materials together with corresponding (if indicated) fourth/fifth generation bonding agents was evaluated using previously extracted human teeth. Five groups of Class V cavity preparations were placed in enamel of the facial surfaces of 200 teeth. Groups A through D included 40 restorations each (4 different restorative materials and their accompanying bonding agent multiplied by 10 teeth) treated with 3 percent, 11 percent, and 16 percent carbamide peroxide bleach and 35 percent hydrogen peroxide bleach. Group E included 40 restorations without treatment of bleach and stood as the control. The restorative materials included were: Fuji II LC resin modified glass ionomer cement, Helioprogress composite resin/-Heliobond adhesive system, Aelitefil composite resin/Allbond 2 adhesive and Dyract compomer material/Prime & Bond adhesive system. Bleaching agents included were Rembrandt 3 percent peroxide gel, Perfecta 16 percent carbamide peroxide gel, White & Brite 11 percent carbamide peroxide solution and Superoxyl 35 percent hydrogen peroxide gel. All teeth were thermally stressed for 100 cycles and microleakage were assessed by dye penetration. The results were tabulated using Analysis of Variance (ANOVA) testing procedures. The Aelitefil composite resin material behaved the least favorably (relative to microleakage) compared to the other materials when exposed to various concentrations of dental bleaching agents.     

Comparison of shear bond strength of composite, compomer and resin modified glass ionomer in primary and permanent teeth: an in vitro study

The aim of this study was to determine the difference in shear bond strength between Composite, Compomer and Resin modified glass ionomer cement in primary and permanent teeth. Thirty extracted primary molars and thirty premolars were selected and buccal surfaces of all the teeth were made smooth with the help of 300 grit silicon carbide paper. These specimens were then divided into 6 groups. Restorative materials were placed on the buccal surfaces of respective specimens with the help of acrylic template. All the specimens were subjected to thermocycling and shear bond strength was tested under the Honsfield testing machine and results were recorded in megapascals (MPa). The resultant scores were tabulated and statistically analysed. It was observed that in case of primary teeth resin modified glass ionomer exhibited significantly higher shear bond strength as compared to composite and compomer, where as on permanent teeth composite demonstrated a significantly higher shear bond strength than that of the resin modified glass ionomer and compomer, where as compomer gave poor shear bond strength in both primary and permanent teeth.     

Effect of four intermediate layer treatments on microleakage of Class II composite restorations

This in vitro study examines the marginal sealing ability of four different intermediate materials applied before placement of a condensable composite. Class II preparations were made with gingival margins placed 1.0 mm apical to the cementoenamel junction of 60 extracted teeth, randomly assigned to five groups of 12. Following restoration, teeth were thermocycled, soaked in 0.5% basic fuchsin, and sectioned longitudinally. The resin-modified glass ionomer cement demonstrated significantly less microleakage than the use of a dentin bonding agent alone or in combination with flowable composite, flowable compomer, or autoploymerizing composite (p < 0.05, Dunn's test). This study supports the use of the glass ionomer open sandwich technique in deep Class II direct composite restorations.     

Effect of flexural load cycling on microleakage of extended root caries restorations

This study evaluated the microleakage of resin-modified glass ionomer, flowable compomer and flowable resin composite restorations on a Class V cavity of simulated advanced root caries under a flexural load cycling condition. Thirty-six non-carious human maxillary premolars were mounted in cylindrical acrylic resin molds. The cavities were prepared in the proximal root surface, from the middle of the buccal surface to the middle of the lingual surface, approximately 1 mm below the cemento-enamel junction, 2 mm axial width and 1.2 mm in depth. The teeth were randomly assigned to one of three groups with 12 teeth in each group: Group 1: Cavity conditioner and Fuji II LC (GC America), Group 2: Prime & Bond NT and Dyract Flow (Caulk-Dentsply), Group 3: Excite and Tetric flow (Ivoclar/Vivadent). Specimens were settled laterally on a fatigue-testing machine that was adjusted to deliver a force of 60N. The specimens were load cycled at 1 Hz for 5000 cycles, placed in a staining solution and sectioned to evaluate microleakage penetration. Results indicate that the coronal and gingival margins showed significant microleakage differences among the three restorations (p<0.05). At the coronal margin, there was no significant difference between Groups 2 and 3. At the gingival margin, there was no significant difference between Groups 1 and 2. It was concluded that the marginal sealing ability of a flowable resin composite under a flexural cycling load was better than in other selected materials and that flowable resin composite with dentin adhesive was a desirable alternative for root caries restorations extended to the proximal surface.     

In vitro evaluation of microleakage of different materials used as pit-and-fissure sealants

The aim of this study was to evaluate in vitro the marginal microleakage of different materials used as pit-and-fissure sealants (Delton, Filtek Flow, Dyract Flow and Vitremer). Fifty-six extracted sound human third molars were randomly assigned to 4 groups (n=14). After sealant placement, the teeth were thermocycled (500 cycles; 5 degrees C, 37 degrees C and 55 degrees C), isolated, immersed in 2% buffered methylene blue dye for 4 h, included in acrylic resin and sectioned longitudinally in a buccolingual direction. The sections were analyzed for leakage using an stereomicroscope. A 4-criteria ranked scale was used to score dye penetration. All materials exhibited dye penetration to some extension and no statistically significant difference was observed among the groups (p>0.05). In conclusion, the findings of this study showed that a flowable composite resin, a flowable compomer and resin-modified glass ionomer placed on occlusal pits and fissures had similar marginal sealing as the unfilled self-cured resin-based sealant.     

The weight change of various light-cured restorative materials stored in water

This study investigated weight changes of seven different light-cured composite restorative materials, one polyacid glass ionomer compomer, and one light-cured glass-ionomer cement following short-term and long-term storage in water. Two packable composites, three universal (hybrid) composites, one microglass composite, one polyacid glass ionomer resin composite (compomer), one microhybrid low-viscosity (flowable) composite, and one light cured glass ionomer composite cement were evaluated in this study. The weight changes of these specimens were measured daily (short-term storage), and they were measured after six weeks (long-term storage) using an electronic analytical balance. A significant difference was found in Ionoliner, Dyract AP, Opticor flow, Charisma, and Solitare 2, but no significant difference was found in the others (Filtek Z 250, Filtek P60, TPH Spectrum, and Valux Plus). Weight change showed a tendency to increase with the time of water storage. The greatest weight change occurred in light-cured glass ionomer composite cement (Ionoliner), which is followed in order by the weight changes in Dyract AP, Opticor Flow, Charisma, Solitare 2, Filtek Z250, Filtek P60, TPH Spectrum; Valux Plus had the least amount of change.     

流动性充填材料用于预防性树脂充填的实验研究

目的　以传统的复合树脂+窝沟封闭剂的方法为对照组,用体外实验的方法评价流动树脂、流动复合体在预防性树脂充填(preventiveresinrestoration ,PRR)治疗中的情况。方法　患小面积龋被拔除第三恒磨牙9颗,分别用流动树脂(A组)、流动复合体(B组)和传统的复合树脂材料+窝沟封闭剂(C组)的方法进行PRR治疗。5 0 %AgNO3 浸染法检查微渗漏;用SEM观察树脂与牙齿的结合情况。结果　①渗透实验表明各实验组和对照组中均存在一定程度的微渗漏;在微渗漏率方面,A组低于对照的C组(P <0 .0 5 ) ,在树脂渗透率方面A组低于B组和C组(P <0 .0 5 )。②SEM上显示A与B组相似,多数标本树脂与牙齿接触的界面上有结合良好的树脂突样结构,但树脂在和窝沟底部与牙体组织结合较差,特别在极细窝沟处;C组中结合良好的界面所占比例较少,复合树脂勉强压入窝洞后充填不实,在沟底部常见宽大裂纹。结论　在流动复合体和流动树脂在PRR治疗时更适用于沿窝沟走向侵润的窄长形态的窝沟内龋,而传统PRR法更适用于单个龋损直径在1 .5～2mm左右的圆形或卵圆形的小面积龋,流动性充填材料在PRR治疗中可作为传统法的一种补充,最大限度地保留健康牙体组织。     

Cytotoxicity of resin-based restorative materials on human pulp cell cultures

OBJECTIVE: The objective of this study was to determine the cytocompatibility of 5 different extracts of resin-based restorative materials (2 resin-modified glass ionomer cements, 1 compomer, and 2 composite resins) on human pulp cells. STUDY DESIGN: Set specimens from 2 resin-modified glass-ionomer cements (Fuji II LC and Fuji IX), 1 compomer (Dyract), and 2 composite resins (Tetric and Superfil) were eluted with culture medium for 2 and 5 days. The effects of resin-based restorative materials on human pulp cells were evaluated with cytotoxicity and mitochondrial activity assays. RESULTS: The results showed that the eluates from resin-modified glass-ionomer, compomer, and composite resins were cytotoxic to primary human pulp cells. In addition, Superfil, Fuji IX, and Tetric demonstrated an inhibitory effect on mitochondrial activity of human pulp cells. It was found that composite resin Superfil was the most toxic restorative material among the chemicals tested. CONCLUSION: The influence of the cytotoxicity depended on the materials tested. Compomer or light-curing resin-modified glass ionomer may initially react more favorably to pulp cells.     

Clinical evaluation of a flowable resin composite and flowable compomer for preventive resin restorations

This clinical study evaluated the retention and caries protection of a flowable resin composite (Flow Line) and a flowable compomer (Dyract Flow) used in preventive resin restorations as compared to the conventional preventive resin technique which uses a resin composite (Brilliant) and a sealant (Concise). This study observed 205 permanent molars with small carious cavities less than 1.5 mm in width, which were obtained from 165 children aged 7 to 15 years. Flowable resin composite was used to treat 75 teeth, and 71 teeth were treated with flowable compomer in both cavities and caries-free fissures. For the control group, 59 teeth were treated with resin composite in cavities and sealant in caries-free fissures. The teeth were evaluated at 3, 6, 12, 18 and 24-month intervals. After three months, all 205 treated teeth were completely intact. After six months, 66 of the 71 teeth treated with flowable resin composite and 65 of the 70 teeth treated with flowable compomer were complete, compared to 57 of the 58 teeth treated with the conventional preventive resin technique. After 12 months, 60 of the 67 teeth treated with flowable resin composite and 61 of the 67 teeth treated with flowable compomer were complete, compared to 51 of the 55 teeth treated with the conventional preventive resin technique. After 18 months, 53 of the 61 teeth treated with flowable resin composite and 54 of the 62 teeth treated with flowable compomer were complete, compared to 47 of the 53 teeth treated with the conventional preventive resin technique. After 24 months, 49 of the 58 teeth treated with flowable resin composite and 45 of the 57 teeth treated with flowable compomer were complete, compared to 42 of the 52 teeth treated with the conventional preventive resin technique. There were no statistically significant differences in retention rates among all groups after 3, 6, 12, 18 or 24-months (p>0.05). One tooth treated with flowable resin composite and one tooth treated with flowable compomer developed caries after 18 and 24 months, respectively, resulting from partial loss at "caries-free fissures." Five teeth developed caries in the conventional preventive resin group; one after 12 months, two after 18 months and one after 24 months, due to loss at cavities. The final caries occurred after 24 months, resulting from partial loss at "caries-free fissures." The differences in caries development among the three groups were not statistically significant (p>0.05). This study suggested that flowable resin composite and flowable compomer could be used for preventive resin restorations. Meanwhile, a vigilant recall should be followed-up due to the risk of failure for flowable materials in "caries-free" fissures. The repair should be performed immediately, in case the preventive resin restoration develops a fracture or loss.     

Liner and light exposure: effect on in-vitro Class V microleakage

This in vitro study evaluated the influence of different glass ionomer liners and curing methods on microleakage of resin composite restorations. Class V root preparations were made in 120 bovine incisors randomly divided into 12 groups according to liner and curing method. The resin composite system (Single Bond + Z100) was inserted and polymerized in one increment in all groups. Cavity preparations were either not lined (control), lined with a resin modified glass-ionomer cement (Vitrebond) or a conventional glass-ionomer cement (Ketac Bond). The restorations were light-cured using one of four curing methods. The teeth were thermocycled and immersed in 0.5% basic fuchsin, sectioned, and dye penetration was measured (Image Tool). No significant difference in leakage among conventional, ramp or pulse-delay methods was seen. High intensity light groups showed significantly greater penetration compared to other curing methods. No significant difference existed in marginal leakage between liners, but microleakage was significantly higher in groups restored using no liner. No relationship between lining technique and light curing method was observed. The use of glass ionomer liners reduced microleakage, while high intensity light curing produced the greatest dye penetration.     

Microleakage of a new improved glass ionomer restorative material in primary and permanent teeth

PURPOSE: The objective of this study was to assess the microleakage of the new conventional glass ionomer, Fuji IXgp in comparison to another conventional glass ionomer (Fuji II), a resin modified glass ionomer (Vitremer) and a composite resin (TPH) in primary and permanent teeth. METHODS: Twenty-five extracted human premolars and 13 primary molars were used. Preparations were made on the center of the buccal and lingual aspects of the premolars (Group A) and the mesio buccal and disto buccal surface as well as the mesio lingual and disto lingual surface of the primary molars (Group B). Each group was randomly divided into five subgroups of 10 specimens each and restored with a different material following the manufacturer's recommendations. Restorations were subjected to thermocycling followed by microleakage evaluation using 50% silver nitrate and computerized image analysis. RESULTS: Two factor analysis of variance revealed a significant main effect of material (P<0.001), a trend toward a main effect of tooth type (P=0.082) and a significant interaction term P=0.016. Materials were a source of difference, so a one-way ANOVA test was used for both primary and permanent teeth together and for each individual group of teeth. Differences were further examined with a multi-variate analysis using the Scheffe' test for both groups of teeth and each individual group of teeth. Each group of teeth restored with the same material was then analyzed with an Independent Samples t-test which showed that conventional glass ionomer (Fuji II) had more leakage than all other groups (P<0.01). In addition TPH showed more microleakage in primary teeth (P<0.02) and Fuji II showed more microleakage in permanent teeth (P<0.02). CONCLUSIONS: Fuji IXgp behaved similarly to the composite (TPH) and to the resin modified glass ionomer (Vitremer). This is a promising result for this material that is targeted for application in conjunction with the Atraumatic Restorative Technique and minimal intervention treatments.     

不同粘结剂与桩核材料微渗漏发生的实验研究

目的：评价不同核材料修复后的牙齿经铸造金属全冠修复后边缘微渗漏的情况。方法：将90个大小相似的完好前磨牙,随机分为9个实验组。对离体牙进行铸造金属全冠及固定尺寸的Ⅱ类洞牙体预备后,分别用3种不同的核材料（树脂、银汞合金、铸造合金）充填窝洞。常规方法铸造镍铬合金全冠,用3种不同的粘结材料（聚羧酸锌、玻璃离子、树脂C＆B）进行粘固。温度循环、染色、包埋后,标本片切,镜下观察冠边缘及核下微漏情况。结果：银汞核与树脂核下微漏小于铸造核（P〈0.05）,树脂粘结剂抗微漏性能优于聚羧酸锌水门汀和玻璃离子粘结剂（P〈0.05）。结论：树脂粘接剂抗微漏性能优于玻璃离子与聚羧酸锌粘结剂。树脂核在预先对粘结面处理后,其抗微漏性能与银汞核近似,优于铸造合金核。     

The effect of incremental versus bulk fill techniques on the microleakage of composite resin using a glass-ionomer liner.

Incremental placement of composite resin has been suggested to reduce microleakage, particularly at the gingival margin of class 5 cervical restorations. It has become clinically advantageous to place a glass-ionomer liner over dentin to further minimize microleakage resulting from a bond between the dentin and glass ionomer, and glass ionomer and resin. The objective of this study was to compare the microleakage behavior of three hybrid composite/bonding agent systems using bulk and incremental filling techniques utilizing a glass-ionomer liner. This was accomplished in vitro using freshly extracted bovine incisors and a Ca45 radioisotope and autoradiography. Sixty bovine incisors were divided into six experimental groups of 10 specimens per group. Class 5 preparations were cut at the cementoenamel junction and restored with the appropriate combination of Herculite XR/Bondlite, P50/Scotchbond 2, or Pertac Hybrid/Pertac Bond. All teeth were lined with the glass ionomer Ketac Bond before the final restoration was placed. The samples were finished and stored for 24 hours in distilled water before thermocycling. The samples were tested for microleakage using a Ca45 radioisotope technique and autoradiography. Incisal (enamel) and gingival (dentin) margins were scored separately for microleakage but grouped for statistical analysis. Results were analyzed using the Kruskal-Wallis H test. Pertac Hybrid exhibited more leakage than Herculite XR or P50. The difference between microleakage of bulk and incremental filling techniques was only significant for P50.     

Single-crystalline ceramic whisker-reinforced carboxylic acid-resin composites with fluoride release

Currently available glass-ionomer, resin-modified glass-ionomer, and compomer materials have relatively low strength and toughness and, therefore, are inadequate for use in large stress-bearing posterior restorations. In the present study, ceramic single-crystalline whiskers were mixed with fluorosilicate glass particles and used as fillers to reinforce experimental carboxylic acid-resin composites. The carboxylic acid was a monofunctional methacryloxyethyl phthalate (MEP). Five mass fractions of whisker/(whisker + fluorosilicate glass), and corresponding resin (resin + MEP), were evaluated. Four control materials were also tested for comparison: a glass ionomer, a resin-modified glass ionomer, a compomer, and a hybrid composite resin. Flexural specimens were fabricated to measure the flexural strength, elastic modulus, and work-of-fracture (an indication of toughness). Fluoride release was measured by using a fluoride ion selective electrode. The properties of whisker composites depended on the whisker/(whisker + fluorosilicate glass) mass fraction. At a mass fraction of 0.8, the whisker composite had a flexural strength in MPa (mean +/- sd; n = 6) of 150 +/- 16, significantly higher than that of a glass ionomer (15 +/- 7) or a compomer control (89 +/- 18) (Tukey's multiple comparison test; family confidence coefficient = 0.95). Depending on the ratio of whisker:fluorosilicate glass, the whisker composites had a cumulative fluoride release up to 60% of that of a traditional glass ionomer. To conclude, combining ceramic whiskers and fluorosilicate glass in a carboxylic acid-resin matrix can result in fluoride-releasing composites with significantly improved mechanical properties.     

Dentine bond strength and microleakage of flowable composite,compomer and glass ionomer cement

Background: To assess in vitro the dentine bond strength and microleakage of three Class V restorations viz. flowable composite, compomer and glass ionomer cement. Methods: Eighteen dentine specimens were prepared and randomly distributed among three groups. Three kinds of restoration materials were each bonded on prepared dentine surfaces in three groups as per the manufacturers’ instructions. Group Aelite: Tyrian SPE (a no‐rinse, self‐priming etchant) + One Step Plus (an universal dental adhesive) + Aeliteflo (a flowable composite); Group Dyract: Prime & Bond NT (a no‐rinse, self‐priming dental adhesive) + Dyract AP (a compomer); Group GlasIonomer: GlasIonomer Type II (a self‐cured restorative glass ionomer). Fifteen dentine/restoration microtensile bond test specimens were prepared from each group and were subjected to microtensile bond strength testing. The bond interfaces were observed morphologically using a scanning electron microscope (SEM). Twenty‐four cervical cavities of 4.0 mm mesiodistal length, 2.0 mm occlusogingival height and 1.5 mm depth were prepared at the cemento‐enamel junction (CEJ) on both buccal and lingual surfaces of each tooth. The cavities were each filled with flowable composite (Group Aelite), compomer (Group Dyract) and glass ionomer cement (Group GlasIonomer) using the same material and methods as for the microtensile bond tests. Microleakage of each restoration was evaluated by the ratio of the length of methylene blue penetration along the tooth‐restoration interface and the total length of the dentine cavity wall on the cut surface. Results: One‐way ANOVA and least significant difference (LSD) tests revealed statistically significant differences among the dentine bond strength for Group Aelite (28.4 MPa), Group Dyract (15.1 MPa) and Group GlasIonomer (2.5 MPa). SEM images showed intimate adaptation in the restoration/dentine interfaces of Group Aelite and Group Dyract. All of the systems tested in this study presented microleakage. However, both Group Aelite (0.808) and Group Dyract (0.863) had significantly less microleakage than Group GlasIonomer (0.964). There were no statistically significant microleakage differences between Group Aelite and Group Dyract, and no statistically significant microleakage differences between the occlusal margin and gingival margin. Conclusions: None of the systems tested in this study completely eliminated microleakage. However, both the flowable composite and compomer provided stronger dentine bond strengths and better margin sealing than the conventional glass ionomer cement. Occlusal forces exerted the same effects on microleakage of the occlusal margin and gingival margin in cervical cavities.     

流体树脂和玻璃离子充填乳磨牙邻面早期龋的疗效分析

目的 比较流体树脂和玻璃离子充填乳磨牙邻面早期龋的临床效果。方法 采用自身对照法,每组各纳入45颗牙齿,分别观察在修复后3、6、12个月的保存情况。结果 玻璃离子修复乳磨牙邻面早期龋总失败率高于流体树脂(P＜0.05),失败率随时间延长而增大,在修复1年后差别出现显著性（P＜0.05)。在各种失败原因分析中,玻璃离子在耐磨性、抗折裂方面明显差于流体树脂（P＜0.05)。结论 玻璃离子充填乳磨牙邻面早期龋的失败率高于流体树脂,但2种材料各有优缺点,临床应用时要根据不同病例选择合适的材料。     

Fluoride release from a new glass-ionomer cement

This study compared the amount and pattern of fluoride release from a new glass-ionomer-based material (nano-ionomer) with other restorative materials and correlated the surface area to volume of nano-sized filler with its capacity to release fluoride in the powder, more quickly increasing the fluoride. The materials evaluated were a nano-ionomer (Ketac N 100), a conventional glass-ionomer cement (GC Fuji II), a resin-modified glass ionomer cement (GC Fuji II LC), a compomer (Dyract F) and a fluoride-releasing resin composite (Tetric N Flow). A resin composite (Synergy Flow) served as the control. Ten specimens were fabricated from each of these materials using a customized metal mold. The fluoride release was measured every 24 hours for the first seven days, and on days 14, 21 and 28, a combination fluoride ion—selective electrode connected to an ion analyzer. The data was analyzed by one-way ANOVA and Tukey HSD test (p=0.05). An initial fluoride “burst effect” was seen with all of the materials, except for the control and compomer. The conventional glass-ionomer cement showed the highest fluoride release on the first three days. The nano-ionomer showed the maximum release of fluoride for the remaining days. A low constant level of fluoride release was seen from the compomer and fluoride-releasing resin composite throughout the study period.     

Biocompatibility of a flowable composite bonded with a self-etching adhesive compared with a glass lonomer cement and a high copper amalgam

This study evaluated the pulpal response and in-vivo microleakage of a flowable composite bonded with a self-etching adhesive and compared the results with a glass ionomer cement and amalgam. Cervical cavities were prepared in monkey teeth. The teeth were randomly divided into three groups. A self-etching primer system (Imperva FluoroBond, Shofu) was applied to the teeth in one of the experimental groups, and the cavities were filled with a flowable composite (SI-BF-2001-LF, Shofu). In the other groups, a glass ionomer cement (Fuji II, GC) or amalgam (Dispersalloy, Johnson & Johnson) filled the cavity. The teeth were then extracted after 3, 30 and 90 days, fixed in 10% buffered formalin solution and prepared according to routine histological techniques. Five micrometer sections were stained with hematoxylin and eosin or Brown and Brenn gram stain for bacterial observation. No serious inflammatory reaction of the pulp, such as necrosis or abscess formation, was observed in any of the experimental groups. Slight inflammatory cell infiltration was the main initial reaction, while deposition of reparative dentin was the major long-term reaction in all groups. No bacterial penetration along the cavity walls was detected in the flowable composite or glass ionomer cement except for one case at 30 days in the glass ionomer cement. The flowable composite bonded with self-etching adhesive showed an acceptable biological com- patibility to monkey pulp. The in vivo sealing ability of the flowable composite in combination with the self-etching adhesive was considered comparable to glass ionomer cement. Amalgam restorations without adhesive liners showed slight bacterial penetration along the cavity wall.