Significant Difference In Microleakage Research Articles

Comparison of Microleakage of Three Adhesive Systems in Class V Composite Restorations Prepared with Er,Cr:YSGG Laser

This study compared microleakage of three adhesives in class V (CI V) composite restorations prepared with Er,Cr:YSGG laser. Changes produced on enamel and dentin surfaces subsequent to laser irradiation influence microleakage of composite restorations. CI V cavities were prepared in 80 sound extracted human premolars with Er,Cr:YSGG laser. The teeth were randomly divided into 4 groups (n = 20). In group 1, a total-etch adhesive was used, and two-step and one-step self-etch adhesives were used in groups 2 and 3, respectively. Group 4 was the control group with no adhesives. Following restoration and thermocycling, microleakage was evaluated. To compare microleakage in occlusal and gingival margins in each group, the Wilcoxon test was used. Kruskal-Wallis analysis was used for comparison of occlusal and gingival microleakage, and two-by-two comparisons were made using the Mann-Whitney U test. There were significant differences in microleakage between occlusal and gingival margins in each group except for the control group. Significant differences were observed in occlusal and gingival microleakage among all the groups. Two-by-two comparisons revealed significant differences in occlusal microleakage between the control group and the other groups. There were significant differences in gingival microleakage between groups 1 and 2 and groups 1 and 3; however, differences in gingival microleakage between groups 2 and 3 were not significant. With all the adhesives, microleakage was significantly higher in gingival margins compared with occlusal margins. In occlusal margins, there were no significant differences in microleakage among the three adhesives. In gingival margins, self-etch adhesives revealed less microleakage than the total-etch adhesive.

Effects of Load Cycling on the Microleakage of Beveled and Nonbeveled Margins in Class V Resin-Based Composite Restorations

This study evaluated the influence of mechanical loading and thermocycling on microleakage of class V resin-based composite restorations with and without enamel bevel. Sixty class V cavity preparations measuring 3.0 mm wide (mesio-gingivally) x 2.0 mm high (occluso-gingivally) x 1.5 mm deep with the occlusal margin in enamel and the gingival margin in cementum were prepared on the buccal surfaces of human premolars using a #12 diamond round bur (Drendel and Zweiling Diamant GmbH, Lemgo, Germany) in a high-speed, water-cooled handpiece. The specimens were then divided into two groups of 30 specimens each, based on the type of enamel cavosurface margin configuration as beveled or nonbeveled (butt joint). After restoring the preparations with a flowable resin-based composite (Tetric Flow, Ivoclar Vivadent-AG, Schaan, Liechtenstein) and finishing and polishing with sequential discs (Sof-Lex Pop-on, 3M-ESPE, St. Paul, MN, USA), the teeth were stored at 37° and 100 percent humidity. Twenty-four hours later, half of the specimens in each group (nonbeveled "N" or beveled "B") were exposed to a cycling loading for 250,000 cycles to simulate occlusal loading and assigned to two subgroups (NL+ or BL+), while the remainder of the specimens in each group were only maintained in a 100-percent-humidity environment, without any cyclical loading, until tested (NL+ or BL+). The specimens were sealed with sticky wax (Kemdent, Associated Dental Products, Swindon, UK) and nail polish. The apical foramen of each tooth was sealed with sticky wax and the rest of the tooth was covered with nail varnish, except for an area within 1.0 mm around the composite restoration. To detect marginal leakage, all of the samples were stored in a 0.5 percent basic fuchsine solution for 24 hours. The specimens were then sectioned longitudinally using a low-speed diamond blade (IsoMet, Buehler Ltd., Lake Bluff, IL, USA), machined, and evaluated under 25X magnification using a stereomicroscope (M9, Wild Heerbrugg, Switzerland). The specimens were scored on a scale from 1 to 4 on the degree of dye penetration. The qualitative data were analyzed by the Mann-Whitney U test at a 5 percent significance level (p<0.05). The null hypothesis of this study was that there is no difference in microleakage between beveled and nonbeveled class V buccal preparations in premolar teeth restored with resin-based composite and subjected to simulated occlusal loading and thermocycling. In each group the gingival margin showed significantly more microleakage than the enamel margin (p<0.05). Load cycling did not result in an increase in microleakage in nonbeveled (p=0.259) or in beveled (p=0.053) occlusal margins. However, the gingival margins showed a statistically significant difference in microleakage after load cycling whether in cavities with enamel occlusal bevel (p=0.004) or in groups without a bevel. This means the enamel margin configuration of the enamel occlusal margin had no effect on decreasing microleakage in the gingival aspect of class V composite restorations. In general, the nonbeveled preparations in this study had significantly less microleakage than the bevel specimens whether they were loaded occlusally or not (p=0.001). Within the limitations of this in vitro study, no benefit was derived from placing an enamel cavosurface bevel on the occlusal margin of a standardized class V composite restoration located at the cementoenamel junction. The most important consideration is to prevent microleakage along the gingival margin regardless of whether the occlusal enamel margin is beveled.

Effect of immediate and delayed post space preparation on the apical seal of root canals obturated with different sealers and techniques

During mechanical preparation of the post space, the root canal filling may be twisted or vibrated, depending on several factors associated with the preparation technique and quality of filling.Objective:The purpose of this study was to investigate the effect of immediate and delayed post space preparation on the integrity of the apical seal.Material and Methods:Sixty-four extracted human incisors were biomechanically prepared using the step-back technique. Sixty roots were randomly assigned to 6 experimental groups of 10 teeth each and the remaining 4 roots served as positive and negative controls (n=2). The root canals in the different groups were obturated with cold lateral and warm vertical condensation of gutta-percha and one of two sealers (Sealapex and Diaket). Post space was prepared either individually or simultaneously. An insulated copper wire was cut into 10-cm-long pieces. In each canal, one piece was inserted to maintain contact with gutta-percha and extended to the outside as one of two working electrodes. A stainless steel wire with the same dimensions of those of the copper wire, used as the other working electrode, was immersed into the background electrolyte from the center of the bottle. The electrical current between standard and experimental electrodes in canals was measured over a period of 10 days applying a conductivity meter. The Kruskal-Wallis test (p=0.05) determined whether there was a significant difference in microleakage among the groups and the Mann-Whitney U test (p=0.01) was used for multiple comparison grouping variables.Results:The results suggest that only the differences between the root canal filling techniques were statistically significant (p<0.01). There were no statistically significant difference in the sealers and the times of filling removal for post space preparation (p>0.01).Conclusion:The quality of the root canal filling is important for the integrity of the apical seal.

Microleakage of Different Temporary Filling Materials in Primary Teeth

The aim of this study was to compare the sealing properties of IRM, Coltosol, Cavit G, Adhesor and Clip, which used as temporary filling material in coronal access openings in extracted human primary teeth. Standardized access cavities of 2 x 2 mm were prepared in the eighty-four, caries-free human primary anterior teeth. The teeth were divided randomly into five groups of 16 teeth each. Temporary restorative materials Group A: IRM (Dentsply), Group B: Coltosol (Coltone), Group C: Cavit G (3M), Group D: Adhesor (Spofa Dental) and Group E: Clip (Voco) were applied according to the manufacturer's directions. The specimens were immersed silver nitrate and placed in film developer under fluorescent for 24 hours. The sectioned specimens were evaluated under a digital microscope at x 20 magnifications and blindly scored for microleakage. Clip presented the least microleakage value whereas; Adhesor and IRM presented the higher microleakage values. There were statistically significant differences between Clip and the others groups, while there were no statistically significant differences in microleakage between IRM, Adhesor, Coltosol and Cavit G. However the leakage scores of Clip and Cavit G were congruent (p = 0.454). Amongst the five materials, Clip exhibited a better sealing ability.

Microleakage between composite-wire and composite-enamel interfaces of flexible spiral wire retainers. Part 2: comparison of amorphous calcium phosphate-containing adhesive with conventional lingual retainer composite

The aim of this study was to test the hypothesis that there is no difference in the microleakage values of a newly developed amorphous calcium phosphate (ACP)-containing adhesive and a conventional lingual retainer composite at the composite-enamel and composite-wire interfaces of flexible spiral wire retainers (FSWRs). Sixty freshly extracted human mandibular incisors separated into three equal groups were used in this study. Multi-stranded 0.0215 inch diameter wire was bonded to enamel using conventional orthodontic adhesive (Transbond LR, 3M Unitek) and ACP-containing composite (Aegis Ortho, Harry J. Bosworth Co.), with or without the use of a primer. The specimens were sealed with nail varnish, stained with 0.5 per cent basic fuchsine for 24 hours, sectioned and examined under a stereomicroscope, and scored for microleakage at the composite-enamel and composite-wire interfaces from the mesial and distal margins. Statistical analyses were performed with Kruskal-Wallis and Mann-Whitney U-tests with a Bonferroni correction. Little or no microleakage was observed between the composite-enamel interface for any of the three groups, and any difference was not statistically significant. The amount of microleakage at the wire-composite interface was higher than that at the enamel-composite interface. Multiple comparison testing showed statistically significant differences in microleakage between Transbond LR and the ACP-containing adhesive used with primer at the composite-enamel and composite-wire interfaces (P < 0.001). ACP-containing adhesive used with primer showed the highest microleakage scores at the composite-enamel (mean: 0.39 +/- 0.42 mm) and composite-wire (mean: 1.66 +/- 0.47 mm) interfaces. The hypothesis is rejected. The ACP-containing composite used with or without primer showed significantly higher leakage at the composite-wire interface, while conventional lingual retainer composite showed lower microleakage scores.

The effect of immediate dentin sealing on the marginal adaptation and bond strengths of total-etch and self-etch adhesives

Sealing ability and bond strengths of total-etch and self-etch dentin adhesives used for immediate dentin sealing have not been assessed and established. The purpose of this study was to determine the effectiveness of immediate dentin sealing (IDS) using total-etch or self-etch dentin adhesives on microleakage and microtensile bond strength. Twenty recently extracted molars were selected, and standard MOD inlay preparations were made with the gingival margins located below the cemento-enamel junction. The teeth were assigned to 4 experimental groups (n=5) according to the indirect composite restoration cementation technique used: (1) immediate dentin sealing with Adper Single Bond (TEBI); (2) conventional adhesive cementation technique using Adper Single Bond (TEAI); (3) immediate dentin sealing using Adper Prompt L-Pop (SEBI); or (4) conventional adhesive cementation technique using Adper Prompt L-Pop (SEAI). The restored teeth were thermal cycled 1,000 times between 5 degrees and 55 degrees C and then immersed in 50% ammoniacal silver nitrate. Three specimens per restoration were evaluated for microleakage, according to predefined scores, and submitted to Friedman's test (alpha=.05). The specimens were then sectioned to obtain 0.8 +/-0.2-mm-thick sticks (with n ranging from 32 to 57 specimens) and submitted to microtensile bond strength (muTBS) testing. The obtained data were submitted to 2-way ANOVA test (alpha=.05). None of the experimental groups demonstrated complete elimination of marginal microleakage. There were significant differences in microleakage of the tested adhesives (P>.001). IDS microleakage scores were similar to those obtained using the conventional cementation technique (CCT) for both adhesives. The highest mean bond strengths were obtained with TEBI (51.1 MPa), whereas SEAI showed the lowest mean bond strengths (1.7 MPa). IDS resulted in significantly higher bond strengths than CCT (P<.001). Total-etch and self-etch adhesives have a significant effect on IDS. IDS resulted in high bond strengths for both adhesives; however, the microleakage was similar to that obtained with CCT. (J Prosthet Dent 2009;102:1-9).

Microleakage under Ceramic and Metallic Brackets Bonded with Resin-Modified Glass Ionomer

To test the null hypothesis that there is no significant difference between the microleakage of adhesive interferences at the occlusal and gingival margins of both ceramic and metallic brackets bonded with light-cured resin-modified glass ionomer and a conventional adhesive. Sixty freshly extracted human maxillary premolar teeth were randomly divided into four groups of 15 teeth each. Metal and ceramic brackets were bonded to groups 1 and 2 with resin-modified glass ionomer adhesive (RMGIA). Metal and ceramic brackets were bonded to group 3 and group 4 with a conventional adhesive (CA) system. A dye-penetration method was used for microleakage evaluation. Microleakage from the occlusal and gingival margins was determined by a stereomicroscope for the enamel-adhesive and bracket-adhesive interfaces. Statistical analysis was performed using the Kruskal-Wallis test and the Mann-Whitney U-test with a Bonferroni correction. The gingival side of all groups exhibited higher microleakage scores compared with the occlusal side for both adhesive interfaces. All bracket and adhesive combinations displayed statistically significant differences in microleakage between the enamel-adhesive and adhesive-bracket interfaces at the occlusal and gingival sides of the brackets (P < .001). When the adhesive systems were compared, the RMGIA showed more microleakage than the CA between the different interfaces. The hypothesis is rejected. RMGIA results in more microleakage between enamel-adhesive interfaces.

Microleakage of Repaired Amalgam

Aims: This invitro study designed to investigate the effect of bonding agent on amalgam repaired with either spherical or admixed alloy. Material and Methods: Cl I cavity preparations were made on the occlusal surface of hundred and twelve extracted human premolars. The teeth were randomly divided into two groups, 56 cavities filled with spherical amalgam and the other 56 cavities filled with admixed amalgam, after aging of restorations, buccal half of the previously placed restorations were removed and each group was divided into two subgroup according to the lining material used. The final number were eight groups of 14 teeth in each. All specimens were thermocycled for 500 times with 15 second dwell time. The samples were stained with 2% methylene blue, sectioned and evaluated for dye penetration. The data were analyzed by Fisher Freeman Halton test.Results: There was a significant differences in microleakage of bonded and non–bonded specimens, the use of bonding agent significantly increase the microleakage of repaired amalgam. Repairing amalgam with similar alloy type significantly reduce the microleakage.Conclusions: Within the limitation of this study, repairing amalgam with bonding agent is acceptable but significantly less microleakage can observed when amalgam repaired without bonding agents. malgam alloy can repaired with different types of alloy, but better marginal seal accomplished when the same types of alloy used for repair

Influence of light-curing unit systems on shear bond strength and marginal microleakage of composite resin restorations

The aim of the present study was to evaluate the influence of different photopolymerization (halogen, halogen soft-start and LED) systems on shear bond strength (SBS) and marginal microleakage of composite resin restorations. Forty Class V cavities (enamel and dentin margins) were prepared for microleakage assessment, and 160 enamel and dentin fragments were prepared for the SBS test, and divided into 4 groups. Kruskal-Wallis and Wilcoxon tests showed statistically significant difference in microleakage between the margins (p 0.05) neither between substrates nor among groups. It was concluded that Soft-Start technique with high intensity end-light influenced negatively the cervical marginal sealing, but the light-curing systems did not influence adhesion.

Effect of Two Light-emitting Diode (LED) and One Halogen Curing Light on the Microleakage of Class V Flowable Composite Restorations

The disadvantages of light cured composite resin materials with respect to microleakage are predominantly a result of polymerization shrinkage upon curing. It has been shown curing methods play a significant role in polymerization shrinkage of light-cured composite resins. The purpose of this study was to investigate the effect of light-emitting diode (LED) light curing units (LCUs) compared with a halogen LCU on microleakage of three different flowable composites using self-etch adhesives. A total of 63 extracted human premolars were prepared with standardized Class V cavity preparations on the buccal and lingual surfaces of each tooth. The occlusal margin of the cavities was located on the enamel and the gingival margin was on dentin. Teeth were randomly assigned to three groups of 21 teeth each as follows: Group 1: Adper Prompt L-Pop + Filtek Flow (3M ESPE); Group 2: AdheSE + Tetric Flow (Ivoclar, Vivadent); and Group 3: Clearfil Protect Bond + Clearfil Protect Liner F (Kuraray Medical Inc.). All the groups were subdivided into three groups according to the curing lights used (n=7). Two LED LCUs, Elipar FreeLight and Elipar FreeLight 2 (3M ESPE), and one halogen-based LCU, Hilux Expert (Benlioglu ), were used. All teeth were then immersed in 0.5% basic fuchsin dye solution for 24 hours after thermocycling (500 cycles; between 5 degrees C to 55 degrees C). The teeth then were longitudinally sectioned and observed under a stereomicroscope (40X magnification) by two examiners. The degree of dye penetration was recorded separately for enamel and dentin. Data were analyzed with the Kruskal-Wallis and Mann-Whitney tests with the Bonferroni correction. No statistically significant differences in microleakage were observed between groups either on enamel or dentin (p>0.05). With the limitation of this in vitro study, the differences in microleakage between LCUs used were not statistically significantly different. Elipar Free Light 2 reduces curing time which can be considered as an advantage.

Effect of Prolonged Thermal Cycling on Microleakage around Class V Cavities Restored with Glass-Ceramic Inserts with Different Coefficients of Thermal Expansion. An In Vitro Study

The purpose of this in vitro study was to evaluate microleakage around Class V glass-ceramic restorations of different coefficients of thermal expansion after prolonged thermal cycling. One hundred and twenty noncarious extracted human premolars (patient age range 12-20 years) were randomly assigned to three groups. Standard Class V preparations were cut in the buccal surface using customised Cerana burs, size no. 3. Glass-ceramic inserts from two manufacturers (Cerana, Nordiska Dental AB, Helsingborg, Sweden; Beta-Quartz, Hager & Werken GmbH, Duisburg, Germany) were used to restore the cavities and were luted with a hybrid, high-viscous composite (Tetric Ceram, Ivoclar Vivadent, Schaan, Liechtenstein) and a bonding agent (Excite, Ivoclar Vivadent, Schaan, Liechtenstein). A control group, without inserts, was bulk-filled with the same composite used as the luting agent. In accordance with American Dental Association guidelines, half of the preparation was in enamel, half in dentine/cementum and had a mesio-distal width of 3 mm, an occluso-gingival height of 3 mm, and a depth of 2 mm. All margins had butt joints. Sixty teeth, selected at random, were not thermal cycled; the remaining 60 teeth were thermal cycled 4000 times between water baths held at 5 degrees C and 55 degrees C and the specimens prepared and examined for microleakage using 2.0% Procion Red (ICI, Slough, UK) dye, buffered at pH7, as a marker. The results were analysed using the Kruskal-Wallis test (ANOVA) at a 95% significance level. At the occlusal margins there was no significant difference in microleakage between the three groups (P>0.5) without thermal cycling. After thermal cycling, microleakage at the occlusal margins was significantly less around cavities restored with Cerana glass-ceramic inserts versus Beta-Quartz and Tetric Ceram (P<0.05 in both cases). At the gingival margins, there was no significant difference in microleakge between the groups before thermal cycling (P>0.5). After thermal cycling, there was significantly less microleakage between Cerana inserts and Tetric Ceram (P<0.05). Comparisons between non-thermal cycled and thermal cycled groups showed there was no significant difference with the Cerana inserts (P=0.5590). The results indicate that, after thermal cycling, restorations restored with Cerana glass-ceramic inserts, which have a coefficient of thermal expansion approximating to that of enamel, show a decrease in marginal microleakage, compared with Beta-Quartz glass-ceramic inserts and Tetric Ceram resin-based composite material. Restorative materials, which have a coefficient of thermal expansion approximating to that of enamel, would seem to be the materials of choice in reducing the problem of marginal microleakege.

In vitro study of the effect of Er: YAG laser irradiation on the apical sealing of different root canal sealers

Objectives:The aim of this study was to determine the effect of Er:YAG laser irradiation used to clean dentinal walls on the apical sealing of root canals filled with different types of sealers.Background Data:Laser application to the dentinal walls removed debris, rendering the root canals free of smear layers and leaving the dentinal canaliculi open.Methods:Sixty-four maxillary canines obtained from laboratory files were instrumented with K-files (Dentsply, Maillefer, Ballaigues, Switzerland) using the crown-down technique, and irrigated with a 0.5% sodium hypochlorite solution. The specimens were divided into two groups of 32 teeth each. In group I, the teeth were instrumented and irrigated with sodium hypochlorite solution, and divided into four subgroups to be sealed with the different materials (Endofill, N-Rickert, Sealapex and Sealer 26). In group II, the root canals were subjected to Er:YAG laser irradiation (200 mJ, 7 Hz and 60 J total energy), followed by root canal sealing as in group I.Results:The data showed lower levels of apical microleakage in the teeth filled with N-Rickert, Sealapex and Sealer 26 cements than in those sealed with Endofill (p < 0.01). No significant difference in microleakage was observed between teeth irrigated only with 0.5% sodium hypochlorite and those submitted to Er:YAG laser application (p > 0.05).Conclusions:The Er:YAG laser irradiation applied to the root canal walls was not able to prevent apical microleakage.

Comparison of Generated Forces and Apical Microleakage Using Nickel-Titanium and Stainless Steel Finger Spreaders in Curved Canals

The purpose of this study was to compare (a) forces generated during lateral compaction and (b) apical microleakage for nickel-titanium (NiTi) and stainless steel (SS) finger spreaders. Twenty-eight extracted human teeth were instrumented using a standardized rotary instrumentation technique. NiTi and SS #30 spreaders were used to obturate molar roots while the forces generated during obturation were measured on a Universal testing machine. Apical microleakage was determined using a fluid filtration method. There was no significant difference in microleakage between spreaders. NiTi spreaders produced significantly less force than SS spreaders in all specimens (p < 0.001).

Microleakage around Glass-Ceramic Insert Restorations Luted with a High-Viscous or Flowable Composite

The purpose of this study was to evaluate microleakage around Class V resin restorations restored with glass-ceramic inserts luted with a high-viscous composite resin or a flowable composite resin. Twenty extracted human premolars (patient age range 12-18 yr) were randomly assigned to four groups. Class V preparations in two groups were filled using a glass-ceramic insert (Megafiller Standardformen, Hager Werken GmbH, Duisburg, Germany) luted with either a hybrid, high-viscous composite (Tetric, Ivoclar Vivadent, Schaan, Liechtenstein) and a bonding agent (Excite, Ivoclar Vivadent) or a flowable composite (Crystal-Essence, Confi-Dental, Louisville, CO, USA) and a bonding agent (Confi-Quick, Confi-Dental). Two groups without inserts served as controls and were bulk filled with either a hybrid, high-viscous composite (Tetric) or a flowable composite (Crystal-Essence). The preparations were made with a no. 330 tungsten carbide fissure bur (Komet, Lemgo, Germany) in a water-cooled, high-speed handpiece with a mesiodistal width of 3 mm, an occlusogingival height of 3 mm, and a depth of 2 mm. All margins had butt joints. The teeth were thermocycled for 24 hours in water baths held at 5 degrees C and 55 degrees C, and the specimens were prepared and examined for microleakage using basic fuchsin as a marker. Relative leakage was recorded according to the extent of dye penetration on a scale of 0 to 4, with 0 indicating no dye penetration and 4 indicating that dye penetration had progressed as far as the cavity floor. The results were analyzed using the Kruskal-Wallis test (nonparametric analysis of variance) and Dunn's multiple comparisons test (p < .05). There was no significant difference in microleakage around inserts luted with a high-viscous composite occlusally (p = .7563) or gingivally (p = .6187) and around cavities bulk filled with the high-viscous composite. There was a significant difference in microleakage around inserts luted with a flowable composite both occlusally (p = .0345) and gingivally (p = .0285) and around cavities bulk filled with the flowable composite. Inserts luted with the flowable composite showed significantly less microleakage than those cemented with the high-viscous material only at the gingival margins (p = .0345). Comparisons of microleakage around the high-viscous and flowable composites showed no significant difference in microleakage at either the occlusal or gingival margins (Dunn's multiple comparisons test p > .5 in all cases). In Class V preparations of the size cut in the present study, ceramic inserts are shown to be of value in reducing microleakage when compared with bulk filling with flowable composites. Microleakage was not significantly improved by using a ceramic insert with a viscous composite compared with the viscous composite alone.

Effect of LED curing on the microleakage, shear bond strength and surface hardness of a resin-based composite restoration

To determine the effect of Light emitting diode (LED) curing on dental resins, microleakage, shear bond strength and surface hardness of a dental composite cured with different LEDs were determined and compared with conventional halogen curing. For microleakage, Class V cavities were restored with Esthet-X, divided into groups, and exposed to one of the curing protocols (Elipar Freelight in soft start and standard modes; Ultra-Lume 2; Spectrum 800). Standard dye penetration tests were performed and the data summarised in a 2-way contingency table of observed frequencies. The Chi-square test was used ( p < 0.05 ) to test for significant differences between the lights. For surface hardness, samples of Esthet-X were exposed to the light-curing units (LCUs). Vickers hardness was determined on the upper and the bottom surfaces. Data was subjected to statistical analysis using ANOVA ( p < 0.05 ). Shear bond strength was determined using a push out method. Comparisons (ANOVA, p < 0.05 ) were made between the different curing protocols. No significant difference in microleakage could be demonstrated between the different LCUs at the enamel side ( p = 0.60 ). At the dentin side only the Elipar Freelight (soft start), could significantly reduce microleakage ( p < 0.01 ). The hardness score for the halogen light was significantly lower than for the LED lights ( p < 0.01 ). The Spectrum 800 and the Elipar Freelight (soft start) have significantly higher shear bond strengths than the others ( p < 0.01 ). It was concluded that the LED source is more efficient for a comparable overall power output.

Microleakage at the composite-repair interface: effect of different adhesive systems

The purpose of the present study was to evaluate the microleakage at the composite-repair interface using different bonding systems. Composite resin specimens (Filtek Z250 - 3M-ESPE) were divided into five groups (n=20) according to the following bonding mechanism: C - control - etching with 35% phosphoric acid; SB1 - etching and application of one coat of Single Bond (3M-ESPE); SB2 - etching and application of two coats of Single Bond (3M-ESPE); SMP1 - etching, application of Scotchbond Multi-Purpose primer (3M-ESPE) followed by the adhesive and, SMP2 - etching, application of Scotchbond Multi-Purpose adhesive (3M-ESPE) without the primer. Thereafter, all groups received new resin application. Samples were thermocycled (500 cycles / 5ºC - 55ºC [±2]) and immersed for 4h in 2% methylene blue buffered dye solution (7.0 pH). Three examiners measured the extent of microleakage in a stereoscope microscope, using four representative scores. For all experimental groups, no significant difference in microleakage at the repair was identified by Kruskal-Wallis test (p > 0.05). Therefore, different types of bonding systems presented the same effect on the dye penetration along the repair interface.

Effects of various irrigation solutions on microleakage of Class V composite restorations

Statement of the problem Irrigation solutions used in the preparation of composite restorations have been reported to contain potential contaminants that may interfere with, and compromise, composite bonding. Purpose The purpose of this in vitro study was to evaluate microleakage of Class V composite restorations after irrigation of acid conditioner with various solutions. Material and methods Standardized Class V preparations (5 mm wide, 4 mm high and 2 mm deep) were made at the cemento-enamel junction on available buccal, lingual, mesial, and distal surfaces of extracted human posterior teeth. The prepared teeth, separated into 7 groups (n = 10), were etched for 10 seconds with a 37% phosphoric acid gel. Each group was irrigated with 1 of the following solutions: (1) tap water, (2) sterile water, (3) sodium chloride solution, (4) filtered water, (5) chlorhexidine, (6) sodium hypochlorite, and (7) distilled water. Each preparation was treated with a bonding agent (Opti-Bond Solo) and then restored with a hybrid composite (Herculite XRV). The restorations were polished with Soflex polishing disks and then thermal cycled for 1000 cycles between 5°C and 55°C with a 20-second dwell time. Assessment of microleakage was performed by application of a dye penetrant, sectioning of the teeth, and examination at original magnification×20. The nonparametric Kruskal-Wallis test (α = .05) was used for statistical analysis. Results Microleakage ranging from 10% to 30% was observed in all groups tested. Tap water exhibited the highest incidence of leakage, sterile water the least, with the other irrigation solutions leading to intermediate leakage. However, there was no significant difference in microleakage resulting from any of the irrigation solutions tested. Conclusion The effect of irrigation solutions used in this in vitro study was not significant.

SELF-ETCH TEK ŞİŞE BONDİNG SİSTEMLERİN SINIF V KAVİTELERDEKİ MİKROSIZINTIYA ETKİSİ

This in vitro study evaluated the effect of two self-etching and three one-bottle bonding systems on microleakage of Class V cavities restored with a resin composite. 50 V-shaped cervical cavities were prepared on each of the buccal surfaces of freshly extracted permanent molars. The cavities were randomly assigned according to used bonding systems: Self-etching bondings; Optibond Solo Plus SE and Prompt-L-Pop and one-bottle bondings; Optibond Solo Plus, Excite and Prime&Bond NT. After applying bonding systems, all cavities were restored with a Charisma resin composite. Restored specimens were stored in distilled water at 37°C for 24 hours. The teeth in each group were thermocycled for 1000 cycles at 5°C and 55°C with a dwell time of 60 seconds, All teeth immersed in 0.5% basic fuchsin dye solution for 24 hours. The teeth then were sectioned in a bucco-palatal/lingual direction and scored on a 0-3 scale at the enamel and gingival margins. Non-parametric statistical analysis of the results showed that there was no significant difference in microleakage between the all bonding adhesives.

Polymerization contraction stress in dual-cure cements and its effect on interfacial integrity of bonded inlays

Objectives. To compare the polymerization contraction stress of resin cements in dual-cure and self-cure modes, and verify its effect on microleakage and gap formation in class I cavities restored with porcelain inlays. Methods. Dual-cure cements (Calibra, Choice and RelyX ARC) were monitored for contraction stress during 30 min in the tensilometer, in the presence or absence of photo-activation. Microleakage was evaluated in porcelain inlays bonded to cavities prepared in bovine incisors, combining the same adhesive (One-Step) with each of the cements in both activation modes. Epoxy replicas of the sectioned specimens were analyzed in the SEM to determine the percentage of discontinuous margins. Results. The stress developed in dual-cure mode was higher than in self-cure mode for all cements. In self-cure mode, no significant difference in stress was found among materials. Choice and RelyX ARC showed higher microleakage in dual-cure mode than in self-cure mode. Calibra did not show a significant difference in microleakage between activation modes. Contraction gap results showed wide variations, and no significant differences were detected among the groups. Gaps occurred more often in dentin, with an overall average of 22±17.5%. Conclusions. The higher stress generated in dual-cure cements subjected to photo-activation may lead to higher marginal leakage. In the confinement condition represented by the class I inlay, even the lower contraction stress of the cements in self-cure mode had enough magnitude to disrupt the bonding to dentin.

Penetration of radiocalcium at the margins of resin and glass ionomer dentine bonding agents in primary and permanent teeth

Objectives: The purpose of this study was to compare the leakage of three resin dentine bonding agents (Prime and Bond, Scotchbond Multi-Purpose, Probond) and a glass ionomer dentine bonding agent (GC Fujibond LC), in cervical cavities prepared in primary and permanent molar teeth restored with a hybrid composite resin (Tetric). Methods: Cervical cavities without a bevel at the cavo-surface margins were prepared in the buccal and lingual surfaces of extracted primary and permanent molar teeth. After being restored, the teeth were stored for 1 week in a saline solution at 37°C and then thermally cycled between 5 and 55°C. Marginal leakage was determined subsequently using a radioactive isotope containing 45Ca and an autoradiographic technique. Results: The results revealed that there were no statistically significant differences in microleakage of the bond between permanent and primary teeth dentine and Fuji Bond LC and Probond dentine bonding agents. The difference between permanent and primary teeth groups for gingival values of the Prime and Bond 2.1 group U=22.5, p=0.0355 and the Scotchbond Multipurpose group U=24.0, p=0.0406 were statistically significant. There were no significant differences between the occlusal and gingival microleakage values in either primary or permanent teeth with Prime and Bond 2.1, Fuji Bond LC and Probond except the difference at Scotchbond Multipurpose in primary teeth. For primary teeth gingival margins, none of the bonding systems were significantly different from the control group. Conclusions: These results indicate that although no statistically significant differences were found between test and control group values, the use of Fuji II LC in cervical cavities with cementum margins in primary teeth would provide the best resistance to microleakage among the test materials while the use of Scotchbond Multi-Purpose would provide the best resistance to microleakage in cervical cavities with cementum margins in permanent teeth.