Effect of insertion technique and adhesive system on microleakage of Class V resin composite restorations

PURPOSE: To evaluate the effect of different insertion techniques and adhesive systems on microleakage of Class V composite resin restorations. MATERIALS AND METHODS: Forty-eight human molars were randomly assigned to four groups (n = 12). Standardized mixed Class V cavities (enamel and dentin margins) were prepared at the CEJ. A total-etch (Adper Scotchbond MultiPurpose) and a self-etching (iBond) adhesive system were evaluated using either an incremental or single-step (bulk) insertion technique. The preparations were restored with Esthet*X micromatrix hybrid composite. The teeth were thermocycled 1000 cycles, immersed in 1% methylene blue dye for 24 h, and invested in acrylic resin. The specimen blocks were then sectioned longitudinally, with dye penetration (microleakage) examined with a 20X binocular microscope. Enamel and dentin margins were scored separately for microleakage using an ordinal ranking system. Results were analyzed using non-parametric tests at a p < 0.05 level of significance. RESULTS: Significance was exhibited between the groups (adhesive material/insertion technique) at the coronal and apical margins. At the coronal margin, the total-etch adhesive/incremental insertion group exhibited significantly less leakage than the other groups, while at the apical margin, the total-etch adhesive/incremental insertion group showed significantly less leakage than the self-etching adhesive/bulk insertion group. Significantly less leakage was found at the coronal margins compared to the apical margins of the material/technique groups. CONCLUSION: The use of a total-etch adhesive system and incremental insertion of composite significantly reduced microleakage at the coronal and apical margins of Class V composite restorations.     

Microleakage of Class V restorations using two different compomer systems: an in vitro study

This study compared the marginal microleakage of Class V cavities restored with Dyract-AP and F2000. Forty Class V cavity preparations were performed on extracted human teeth. As a negative control, twenty teeth were used without Class V preparations. The apical foramina of the teeth were sealed with a layer of varnish and amalgam restorations. Class V cavity preparations with occlusal margins in enamel, and gingival margins in cementum or dentin that measured approximately three millimeters in width (gingival-occlusal) and length (mesial-distal), were prepared on the buccal surface of the teeth. Samples were divided randomly into 2 groups of 15, and restored per manufacturer's instructions using experimental primer/conditioner (PCC, D/C) and Single Bond Adhesive (3M). All restorations were polished with an abrasive finishing kit. After storage in 37 degrees C water for 24 hours, all specimens were thermocycled between 5 degrees C and 55 degrees C for 500 cycles with a 30-second dwell time, followed by immersion in 0.2% basic fucsine for 24 hours. Teeth were then embedded in cold cure acrylic resin, sectioned longitudinally, and the dye penetration at the enamel and cementum margins were scored at 30x magnification. Evaluations were rated from 0 to 3 (0 = no leakage; 1 = dye penetration up to one-half of the preparation depth; 2 = dye penetration more than one-half preparation depth, but less than the axial wall; 3 = dye penetration along the axial wall). Both F-2000 and Dyract-AP indicated no leakage in the enamel margins. Dyract-AP showed no leakage at either the enamel or dentin margins. Fisher's Exact Test revealed that this difference in dentin margins was statistically significant (p < 0.05). Under the given conditions, Dyract-AP and F-2000 demonstrated resistance to microleakage in enamel, and showed Dyract-AP to be more resistant to microleakage in dentin than F-2000.     

Influence of resin composite shade and location of the gingival margin on the microleakage of posterior restorations

OBJECTIVE: The objective of this in vitro study was to evaluate the influence of resin composite shade and location of the gingival margin (enamel or dentin) on the microleakage of proximal restorations on posterior teeth. Methods and MATERIALS: Sixty freshly extracted human third molars were prepared with standardized Class II box-shaped cavities with proportional size and shape, with distal gingival margins located on the enamel and mesial gingival margins on dentin. The teeth were randomly divided into 6 groups according to resin shade (n=10): G1-Incisal; G2-A1; G3-A2; G4-A3; G5-A3.5; G6-A4. The cavities were restored with a total-etch 1-bottle adhesive system and microhybrid resin composites inserted in 4 increments, light cured for 20 seconds through the occlusal surface, then an additional 60 seconds for each surface. After 1 week of immersion in distilled water, the specimens were thermocycled (500 cycles, 5 degrees -55 degrees C, 30 seconds dwell time), sealed with nail polish and immersed in 0.5% basic fuschin solution for 24 hours. The restorations were sectioned longitudinally, and microleakage was evaluated using a 0-3 score scale. RESULTS: Data were subjected to Kruskal-Wallis and Wilcoxon tests at p<0.05. No statistically significant differences between groups were observed regarding the shade of resin composite (p=0.8570). When margins (enamel or dentin) were considered separately, statistically significant differences were observed between groups (p<0.0001), with enamel margins exhibiting lower degrees of microleakage. CONCLUSION: The variation of resin composite shades utilized in this study did not influence the microleakage of Class II restorations. However, the location of the gingival margin influenced the microleakage.     

Marginal permeability of self-etch and total-etch adhesive systems

This study evaluated microleakage in vitro of self-etch and multi-step, total-etch adhesive systems. Ninety-six extracted non-carious human molars were randomly assigned to eight groups (n=12) and restored with different adhesive systems: Optibond Solo Plus, iBond, Adper Prompt L-Pop, Xeno III, Simplicity, Nano-Bond, Adper Scotchbond Multi-Purpose and Touch & Bond. Each group was treated following the manufacturer's instructions. Class V cavities were prepared on the facial or lingual surfaces of each tooth with coronal margins in enamel and apical margins in cementum (dentin). The teeth were restored with Z-100 resin composite. After polishing with Sof-Lex disks, the teeth were thermocycled for 1000 cycles and coated with nail varnish to within 1.0 mm of the restoration. The teeth were stained in 1% methylene blue dye for 24 hours and sectioned from the facial to lingual surface. Dye penetration (microleakage) was examined with a 20x binocular microscope. Enamel and dentin margin leakage was scored on a 0 to 3 ordinal scale. Data were analyzed using Kruskal-Wallis Analysis of Variance and Mann-Whitney U tests. Comparison of the adhesive groups at the enamel margin revealed: 1) Adper Scotchbond Multi-Purpose exhibited significantly less leakage than the other adhesive groups (except iBond); 2) among the self-etch adhesive groups, iBond exhibited significantly less leakage than Nano-Bond and 3) the other adhesive groups clustered intermediately. In contrast, there were no significant differences among the adhesive groups when the dentin margin was evaluated. A Wilcoxin signed rank test showed significantly less leakage at the enamel margins compared to the dentin margins of the eight adhesive systems tested. All data were submitted to statistical analysis at p<0.05 level of significance.     

The effect of occlusal loading on the microleakage of class V restorations

OBJECTIVE: This in vitro study evaluated the microleakage of Class V cavities restored with a resin composite and different adhesive systems after occlusal loading. METHODS & MATERIALS: Standardized box-shaped Class V cavities were prepared on the buccal side of 135 non-carious human premolars. The teeth were randomly divided into three groups of 45 premolars each and restored as follows: Group 1-two-step total-etch adhesive (Single Bond, 3M) + resin composite (Supreme, 3M ESPE); Group 2-two-step self-etch adhesive (Clearfil SE, Kuraray) + resin composite and Group 3-one-step self-etch adhesive (Xeno III, Dentsply) + resin composite. The restorations were finished with aluminum oxide discs (Sof-Lex, 3M). Fifteen teeth in each group received 10,000 x 100 N and 250 N occlusal loads, respectively, and the remaining 15 teeth served as the control. The premolars were immersed in 2% methylene blue for 24 hours. The dye penetration was examined under a stereomicroscope, and the results were statistically analyzed by Kruskal Wallis, Mann-Whitney U and Wilcoxon Signed Rank tests to determine differences between the groups. RESULTS: Gingival margins showed more dye penetration than occlusal margins in all the tested groups (p<0.05). In all the tested adhesive systems, 100 N occlusal loading did not change dye penetration; however, Groups 1 and 2 exhibited better marginal sealing than Group 3 at the enamel margins under 250 N occlusal loading. CONCLUSION: Within the limitations of this in vitro study, it may be concluded that enamel margins provided better marginal sealing than dentin/cementum margins and the two-step self-etch adhesive exhibited better marginal sealing than an all-in-one adhesive at the enamel margins under 250 N occlusal loading.     

Influence of flowable liner and margin location on microleakage of conventional and packable class II resin composites

This in vitro study evaluated gingival wall microleakage in packable and microhybrid conventional composite restorations with and without a flowable composite liner. Each group was evaluated with gingival margins situated in both enamel and cementum/dentin. Two hundred and forty Class II cavities were prepared in extracted third molars, half with gingival margins in enamel and half with margins in dentin/cementum. In groups of 30, restoration was undertaken with packable alone (3M Filtek P60), conventional alone (3M Z250), packable plus flowable liner (3M Filtek Flow) and conventional plus flowable liner. All used 37% phosphoric acid etch and Scotchbond 1 (3M) as the bonding system. After restoration, the teeth were thermocycled (between 5 degrees C, 37 degrees C and 60 degrees C) 1,500 times, soaked in 0.1% methylene blue, sectioned and microleakage from the gingival margin scored. Statistical analysis was performed using Kruskal Wallis and Mann-Whitney U tests. There was no significant difference between systems in terms of leakage scores when gingival margins were situated in enamel (p=0.70). All restorations with margins in cementum/dentin leaked significantly more than those with margins in enamel (p<0.001). There was no significant difference between leakage scores of 3M Z250 and Filtek P60 with cementum/dentin gingival margins (p=0.68). Use of a flowable composite liner (3M Filtek Flow) against cementum/dentin was associated with increased microleakage (p<0.001). In this study, leakage scores suggest that gingival margins should be placed in enamel. The conventional and packable resin composites tested were not associated with differences in microleakage. Leakage data do not support the use of flowable resin composite linings in Class II resin composite restorations.     

Comparison of microleakage for three one-bottle and three multiple-step dentin bonding agents.

PURPOSE: This in vitro study compared the ability of several recently introduced 1-bottle adhesives to their preceding multiple-step dentin bonding agents in reducing microleakage around Class V composite restorations. MATERIAL AND METHODS: Facial and lingual Class V cavities were prepared in 48 molar teeth, which were randomly divided into 6 equal groups. Three groups used the fourth-generation multiple-step systems, and 3 used the fifth-generation single-bottle adhesives. All cavities were restored by composite and subjected to thermocycling and intermittent occlusal loading. After immersion in 0.5% basic fuchsin, the teeth were cut faciolingually in 5 consecutive sections and evaluated for dye penetration using a binocular stereomicroscope. RESULTS: There was no statistically significant difference in the degree of microleakage comparing the adhesive's generation and manufacturer and the location of the cavity margins. A significant interaction was found between margin location and manufacturer, which implied that the sealing capacity at the enamel and cementum margins was material-specific. CONCLUSION: Scotchbond Multi-Purpose and Single Bond adhesives provided the best seal for enamel margins, and One-Step and Optibond FL adhesives were best for cementum margins.     

Effect of single step adhesives on the marginal permeability of Class V resin composites

This in vitro study evaluated the coronal and apical marginal microleakage of four self-etch, seventh generation adhesive systems. Sixty non-carious human molars were randomly assigned to four groups (n = 12). Class V cavities were prepared on the facial or lingual surface of each tooth with coronal margins in enamel and apical margins in cementum (dentin) at the cementoenamel junction. The preparations were restored using four self-etch adhesive systems (iBond, G-Bond, Xeno IV and Clearfil S3 Bond) and a control (no adhesive), followed by insertion of Gradia Direct microfilled hybrid resin composite. The teeth (specimens) were thermocycled 1,000 cycles, immersed in 1% methylene blue dye for 24 hours and invested in acrylic resin. The specimen blocks were then sectioned longitudinally, with dye penetration (microleakage) examined using a 20x binocular microscope. Coronal and apical margins were scored separately for microleakage using a 0-3 ordinal ranking system. Data were analyzed using non-parametric tests at a p < 0.05 level of significance. A comparison of adhesive and control groups at the coronal and apical margins revealed that significant (p < .0001) differences were exhibited. At the coronal margin, Xeno IV revealed significantly less leakage than the other adhesives, with Clearfil S3 Bond exhibiting significantly less leakage at the apical margin. Groups with no adhesive treatment (control) showed significantly greater leakage at both the coronal and apical margin locations. A Wilcoxon signed rank test showed no significant differences at the coronal compared to the apical margins of the four adhesive systems and control tested.     

Assessing microleakage in resin composite restorations rebonded with a surface sealant and three low-viscosity resin systems.

OBJECTIVES: The aim of this study was to assess the ability of three low-viscosity resin systems (Unibond, Single Bond, and Fluorseal), used as rebonding agents, and a specific surface-penetrating sealant (Fortify) to prevent microleakage in Class V resin composite restorations. METHOD AND MATERIALS: Fifty Class V cavities with the occlusal margin in enamel and the cervical margin in dentin and cementum were prepared on both the buccal and lingual surfaces of sound extracted premolars and restored with a hybrid light-cured resin composite. After finishing and polishing, restorations were randomly assigned to one of five equal groups (n = 10): a control, without surface sealing, and four experimental groups in which margins were etched and rebonded. Specimens were thermocycled, immersed in a 50% silver nitrate solution, sectioned longitudinally, and analyzed for leakage at the occlusal and cervical interfaces. RESULTS: Statistical analysis showed significantly less leakage at the enamel margins for all groups. Fortify and Unibond were statistically similar and provided better marginal sealing at dentin and cementum interfaces. Fluorseal showed the poorest ability to prevent microleakage. CONCLUSION: The rebonding technique may substantially minimize microleakage at dentin and cementum margins of composite restorations, when a resin system with sufficiently low viscosity is used as a surface sealant, regardless of whether it has been specified for such a purpose.     

Effect of dentin deproteinization on microleakage of Class V composite restorations

The role of the collagen fibers in dentin adhesion has not clearly been established. Therefore, this laboratory study evaluated the microleakage at resin-dentin and resin-enamel interfaces of Class V composite restorations after etching enamel and dentin with phosphoric acid (H3PO4) or after etching with H3PO4 followed by deproteinization with 5% sodium hypochlorite (NaOCl) to prevent the formation of a hybrid layer. Ten extracted human molars were used to prepare standardized Class V cavities on both buccal and lingual surfaces. The teeth were randomly divided in two groups: 1) Class V cavities that were etched with H3PO4 for 15 seconds; b) Class V cavities that were etched with H3PO4 for 15 seconds followed by collagen removal with 5% NaOCl for two minutes. The cavities were restored using the Prime & Bond 2.1 bonding system and TPH resin composite. The specimens were stored in water for 24 hours at 37 degrees C and thermocycled 500 times between water baths kept at 5 degrees C and 55 degrees C. After thermocycling, specimens were immersed in a 0.5% aqueous solution of basic fuchsin for 24 hours. Three longitudinal sections of each restoration were obtained and examined with a stereomicroscope for qualitative evaluation of microleakage. The data were statistically analyzed by Mann-Whitney U and Wilcoxon matched pairs signed ranked tests. Extra specimens were analyzed with the scanning electron microscope (SEM). Occlusal margins (enamel margins) resulted in statistical lower degree of leakage than gingival margins (dentin/cementum margins) in both treatment groups. For each type of margin, there were no statistically significant differences between the etched and the etched and deproteinized groups. Under the SEM, occlusal surfaces showed no detachment between enamel and dentin, while dentin/cementum resulted in gap formation.     

Microleakage of direct and indirect composite restorations with three dentin bonding agents

This study evaluated the marginal sealing ability of direct and indirect (inlay) resin composite restorations with three dentin bonding systems. Forty-eight freshly extracted bovine incisor teeth were randomly assigned to four groups for bonding with Syntac Single-Component, Excite (Vivadent, Liechtenstein), ScotchBond Multi-Purpose Plus (3M Dental Products, St Paul, MN 55144, USA) and a control with no bonding agents. Class V cavities were cut in both buccal and lingual surfaces. The coronal half of each preparation was in enamel and the gingival half was in cementum or dentin. Half of the specimens in each group were restored with direct and the remainder with indirect technique. The teeth were stored in 37 degrees C water for 30 days, then thermocycled. After immersion in 0.5% basic fuchsin, the teeth were cut faciolingually and evaluated for dye penetration using a binocular stereomicroscope. There was no significant difference among the bonding systems for either the direct or indirect technique or between the two techniques used for each system, however, the indirect technique showed significantly (p = 0.001) less microleakage than the direct technique in control groups. All groups showed more leakage at the cementum margins except Excite with direct technique, where microleakage at the incisal and gingival margins was almost equal.     

The effect of flowable resin composite on microleakage in class V cavities

This in vitro study investigated the microleakage of flowable resin composite as a restorative material and as a liner (either light cured separately or co-cured with hybrid resin composite) in Class V cavities. A light-cured hybrid resin composite was used as a control. Twenty extracted human premolars were prepared with standardized Class V cavity outlines on the buccal and lingual surfaces. The occlusal margin of the cavities was on enamel and the gingival margin was on dentin. One bottle adhesive system (Single Bond) was used after etching enamel and dentin with 34.5% phosphoric acid for 15 seconds. The cavities were randomly divided into four groups of 10 each and restored according to the manufacturers' instructions: Group I-Hybrid resin composite (Z100); Group II-Flowable resin composite (Filtek Flow); Group III-Flowable resin composite (Filtek Flow)+Hybrid resin composite (Z100); light cured separately; Group IV-Flowable resin composite (Filtek Flow)+Hybrid resin composite (Z100); co-cured. The samples were thermocycled 200 times with a 30-second dwell time. They were then immersed in a 0.5% basic fuchsin solution for 24 hours, sectioned and analyzed by stereomicroscopy. The degree of dye penetration was recorded and analyzed with the Kruskal-Wallis and Mann-Whitney U tests. The results of this study indicate that there was no leakage at the occlusal margin for either restoration. Statistically significant differences were found among the groups at the gingival margin. No statistically significant difference was observed between the occlusal and gingival margins except in Group IV. The combination of flowable resin composite and hybrid composite light cured separately yielded the best result in this study. The most leakage was observed when this combination was co-cured. The resistance to microleakage of flowable resin composite as a restorative material is similar to that of hybrid resin composite.     

Effect of photoactivation systems and resin composites on the microleakage of esthetic restorations

AIM: The aim of this study was to evaluate the influence of four photoactivation systems [quartz tungsten halogen (QTH), light-emitting diode (LED), argon ion laser (AL), and plasma arc curing PAC)] on cementum/dentin and enamel microleakage of Class II restorations using a microhybrid [Z250-3M ESPE] and two packable composites [(SureFil-Dentsply and Tetric Ceram HB-Ivoclair/Vivadent]. METHODS AND MATERIALS: Three hundred sixty "vertical-slot Class II cavities" were prepared at the mesial surface of bovine incisors using a 245 carbide bur in a highspeed handpiece. Specimens were divided into twelve groups (composite-photoactivation systems). Half of the specimens had the gingival margin placed in enamel (n=15) and the other half in cementum/dentin (n=15). Composites were inserted and cured in 2 mm increments according to manufacturers' recommended exposure times. After polishing, the samples were immersed in 2% methylene blue solution, sectioned, and evaluated at the gingival margins. Data were submitted to statistical analysis using the Kruskal-Wallis and Mann-Whitney tests. RESULTS: No significant differences were found among the photoactivation systems and among resin composites (p>0.05). Microleakage was not significantly affected by location (enamel vs. cementum/dentin, p>0.05). These findings suggested neither the photoactivation systems nor the resin composite types might have an effect on the microleakage at gingival margins Class II cavities.     

Microleakage of different resin composite types.

OBJECTIVE: The purpose of this study was to evaluate the microleakage of Class V cavity preparations restored with three different types of resin composite and an ormocer. METHOD AND MATERIALS: Forty Class V cavities were prepared in buccal and lingual surfaces of 20 recently extracted molar teeth. The occlusal margin of each restoration was on enamel and the gingival margin on dentin. Teeth were randomly assigned to four groups of 5 teeth each and restored as follows: Group I, flowable resin composite (Tetric Flow); Group II, hybrid resin composite (Z100); Group III, packable resin composite (Solitaire 2); Group IV, organically modified ceramics-ormocer (Admira). In all groups, the manufacturers' instructions were strictly followed. All restorative resin composite materials were placed in one increment. All teeth were then immersed in 0.5% basic fuchsin solution for 24 hours after thermocycling (200 cycles; between 4 degrees C to 60 degrees C). The teeth then were longitudinally sectioned and observed under a stereomicroscope. The degree of dye penetration was recorded and analyzed with the Kruskal-Wallis and Mann-Whitney tests. RESULTS: No statistically significant differences in microleakage were observed between groups either on enamel or dentin. CONCLUSION: All restorative materials demonstrated equal effectiveness in reducing microleakage.     

Microleakage in MOD resin composite with three dentin bonding agents

The extent of microleakage under MOD composites was studied when an aluminum oxalate dentin bonding agent (Tenure), a phosphonated resin bonding agent (Bondlite), and a glass-ionomer cement (Ketac Silver) were used. Three groups of 10 extracted molars were prepared with MOD cavities; one box ended on enamel, the other on cementum. In Group 1, Bondlite was applied to dentin and etched enamel before the sample was restored with a light-cured hybrid composite. In Group 2, a 2-mm increment of Ketac Silver was placed in each box before Bondlite and composite. In Group 3, Tenure was applied to dentin before being restored. Teeth were thermal-cycled, stained in silver nitrate, sectioned, and scored for microleakage. Microleakage along the gingival floor was significantly less at enamel margins than at cementum margins in all three groups. All groups showed severe marginal microleakage on cementum.     

Microleakage of Composite Restorations Bonded with Three New Dentin Bonding Agents

ABSTRACT: This report evaluates the impact of two dentin bonding techniques on microleakage of Class V restorations bonded with three new dentin bonding systems. Forty-eight extracted human premolar and molar teeth were randomly assigned to four groups for bonding with EBS Bonding System (ESPE, Seefeld, Germany); Syntac Single-Component (Ivoclar-Vivadent, Schaan, Liechtenstein); Scotchbond 1 (3M Dental Products, St. Paul, Minnesota); and a control, Prime and Bond 2.1 (Dentsply, DeTrey, Konstanz, Germany). Cavities were cut in both the buccal and lingual surfaces. The coronal half of each preparation was in enamel, and the gingival half was in cementum or dentin. The cavities were restored with composite after the application of dentin bonding agents, using two different drying techniques for each material. The teeth were stored in distilled water for 6 days at 37°C and then thermocycled. The restorations were examined microscopically for leakage, using Procion brilliant red as a marker. All groups showed microleakage at both the enamel and dentin margins. At the gingival margin, there was no significant difference between any of the experimental materials and the control for either wet bonding (Kruskal-Wallis: p .8920) or dry bonding (Kruskal-Wallis: p .9973); or between the two techniques for each material (Mann-Whitney U in all cases p > .05). Scanning electron microscopic examination confirmed that the zones of microleakage, as indicated by dye penetration, were principally resin-cohesive failures within the collagen-rich hybrid layer. Three water-based bonding agents were unable to prevent microleakage at either the enamel or dentin margins of Class V cavities regardless of which bonding technique was employed. All systems behaved equally.     

Microleakage of composite restorations bonded with three new dentin bonding agents.

This report evaluates the impact of two dentin bonding techniques on microleakage of Class V restorations bonded with three new dentin bonding systems. Forty-eight extracted human premolar and molar teeth were randomly assigned to four groups for bonding with EBS Bonding System (ESPE, Seefeld, Germany); Syntac Single-Component (Ivoclar-Vivadent, Schaan, Liechtenstein); Scotchbond 1 (3M Dental Products, St. Paul, Minnesota); and a control, Prime and Bond 2.1 (Dentsply, DeTrey, Konstanz, Germany). Cavities were cut in both the buccal and lingual surfaces. The coronal half of each preparation was in enamel, and the gingival half was in cementum or dentin. The cavities were restored with composite after the application of dentin bonding agents, using two different drying techniques for each material. The teeth were stored in distilled water for 6 days at 37 degrees C and then thermocycled. The restorations were examined microscopically for leakage, using Procion brilliant red as a marker. All groups showed microleakage at both the enamel and dentin margins. At the gingival margin, there was no significant difference between any of the experimental materials and the control for either wet bonding (Kruskal-Wallis: p = .8920) or dry bonding (Kruskal-Wallis: p .9973); or between the two techniques for each material (Mann-Whitney U in all cases p > .05). Scanning electron microscopic examination confirmed that the zones of microleakage, as indicated by dye penetration, were principally resincohesive failures within the collagen-rich hybrid layer. Three water-based bonding agents were unable to prevent microleakage at either the enamel or dentin margins of Class V cavities regardless of which bonding technique was employed. All systems behaved equally.     

Influence of time and thermocycling on marginal sealing of several dentin adhesive systems.

This study evaluated the in vitro microleakage of six dentin adhesive systems. Triangle-shaped Class V cavities with coronal margin in enamel and gingival margin in cementum or root dentin were cut in the buccal surfaces of 90 non-carious single-root human teeth. These teeth were randomly assigned into six groups (n = 15) for the evaluation of six different dentin adhesive systems: One Step, Prime & Bond 2.0, Syntac Single, Single Bond, Optibond Solo and Syntac Sprint. The preparations were restored with Degufill Ultra composite and polished using the Enhance system. Each group was randomly divided into three subgroups (n = 5): samples of the first subgroup were immersed in 2% methylene blue solution for seven days; those of the second subgroup remained in a similar solution for 31 days; those of the third subgroup were thermocycled 500x at 5-55 degrees C and immersed in 2% methylene blue for seven days. All 90 teeth were then embedded in methacrylate and bucco-lingually sectioned; the dye penetration was evaluated using an 0-4 ordinal scale. All of the dentin adhesive groups showed minimal leakage at the enamel margins with increased leakage at the gingival margins. Optibond Solo showed the best outcomes among the dentin adhesives tested.     

The effect of flexural load cycling on the microleakage of cervical resin composites

Although several in vitro studies have attempted to investigate the microleakage of Class V resin composites under loading, the effect of load cycling on marginal seal is still unclear. This may be due to the fact that axial loads were applied to the specimens. This study investigated the effect of flexural loads on marginal sealing of cervical resin composites. One hundred and fifty cervical wedge-shaped cavities were restored with Clearfil Photo Bond, Clearfil Liner Bond 2, Scotchbond Multi-Purpose with 10% maleic acid, Scotchbond Multi-Purpose with 35% phosphoric acid or Mac-Bond 2 according to the manufacturers' instructions. After the restorations were finished, 10 specimens from each group were immersed in 0.5% basic fuchsin solution to examine microleakage. Prior to dye solution immersion, 20 specimens were subjected to flexural load cycling (1 mm labio-lingual or linguo-labial displacement at the incisal edge, 10,000 cycles, 1 cycle/second). The data were analyzed using the Kruskal-Wallis test and the Mann-Whitney U-test (p<0.05). When the flexural loads were not applied, both the incisal and apical margins showed good marginal sealing, regardless of the adhesive system used. Labio-lingual loading significantly deteriorated the marginal integrity at the incisal enamel margins, except for those restored with Clearfil Photo Bond. However, only Clearfil Photo Bond demonstrated a significant increase in microleakage along the apical dentin margins. Linguo-labial loading had no significant effect on the marginal seal.     

Comparison of microleakage of three acid-base luting cements versus one resin-bonded cement for Class V direct composite inlays

STATEMENT OF PROBLEM: Demineralized dentin beneath set cement may adversely affect microleakage under fixed restorations. PURPOSE: Microleakage of direct composite inlays cemented with acid-base cements and a methyl methacrylate resin cement were evaluated to determine their effect on the integrity of the underlying hybridized dentin. MATERIALS AND METHODS: Sixty Class V box preparations (3 mm x 3 mm x 1.5 mm) were precisely prepared in previously frozen bovine teeth with one margin in enamel and another margin in dentin. Direct composite inlays (EPIC-TMPT) for each preparation were divided into 4 groups of 15 specimens each and cemented with 3 acid-base cements (control group): Elite, Ketac-Cem, Hy-Bond Carbo-Cem, and 1 adhesive resin cement: C&B Metabond. All specimens were stored in distilled water for 24 hours at 37 degrees C before immersion in 0.5% basic fuchsin for 24 hours. The dye penetration was measured on the sectioned specimens at the tooth-cement interface of enamel and cementum margins and recorded with graded criteria under light microscopy (Olympus Vanox-T) at original magnification x 50, 100, and 200. A Kruskal-Wallis and the Mann-Whitney test at P<.05 were used to analyze leakage score. RESULTS: All cementum margins of the 3 acid-base cements tested demonstrated significantly higher leakage scores than cementum margins for inlays cemented with the resin cement tested(P<.01). No leakage along the tooth-cement interface was found for inlays retained with the adhesive resin cement. CONCLUSIONS: Within the limitations of this study, the 3 acid-base cements tested exhibited greater microleakage at the cementum margins than did the adhesive resin cement that was tested.