Dentin Margins Research Articles

Two Adhesive Systems-effect on Adhesion to Tooth Structure

This study evaluates and compares by dye penetration method and SEM photomicrographs the sealing obtained using two different classes of adhesive systems (etch-and-rinse and self-etch with selective etching) with SDR (Dentsply) bulk fill composite. 84 class V cavities were prepared on oral and vestibular face of 42 intact, freshly extracted wisdom teeth. The cavities were randomly divided in two groups and restored: Group 1 with prime &bond one select (Dentsply) and SDR (Dentsply) and Group 2 with prime&bond one Etch&Rinse (Dentsply) and SDR (Dentsply). Prime&bond one Select (Dentsply) is a single component adhesive and can be used in self etch mode, in selective enamel etch mode, or in etch-and-rinse mode. We chosen for this study the selective etch of the enamel mode. Prime&bond one Etch Rinse (Dentsply) is a universal etch-and-rinse one-bottle dental adhesive, designed to be used in two steps. The bulk fill composites are commonly used in modern dentistry due to their properties of low polymerization shrinkage and curing in layer of 4 mm depth, offering the practitioner a fast clinical procedure with good results. The results showed a good sealing at enamel and dentin margins with no statistically significant difference between adhesives, even though the mean of enamel infiltration was smaller for Group1. Furthermore the results show that there were differences between the two groups, for the infiltrations at the enamel, the values of microleakage being arithmetically higher for Group 1, but with no statistically difference between the two groups.SEM images showed for both groups a good adhesion surface with the tooth, but the hybrid layer of the total-etch adhesives is different from the hybrid layer formed by self etch adhesives, in terms of thickness, uniformity. In conclusion both adhesive systems have equivalent sealing qualities and can be successfully used with SDR.

In vitro evaluation of microleakage in Class II composite restorations: High-viscosity bulk-fill vs conventional composites.

This study compared marginal microleakage of Class II cavities restored with bulk-fill resin (Filtek™ Bulk Fill) and conventional composite resin (Filtek™ Supreme XTE). Two standardized Class II cavities were prepared in forty extracted human molars. The gingival margin was located above the cemento-enamel junction for twenty molars (groups 1 and 2) and apically for the other twenty (groups 3 and 4) (n=20). The occlusomesial cavity was filled with bulk-fill resin by insertion in bulk (groups 1 and 3) and the occlusodistal cavity was restored with conventional composite using incremental technique (groups 2 and 4). The teeth were thermocycled (500 cycles 5-55°C), stained and observed under light microscope. The microleakage was significantly lower in gingival margins located in enamel compared with dentin margins (p<0.01). There was no statistically significant difference between groups 1 and 2 (p=0.86) and groups 3 and 4 (p=0.26). Bulk-Fill resins presents gingival microleakage similar to conventional composites.

Inhibition of Demineralization at Restoration Margins of Z100 and Tetric EvoCeram Bulk Fill in Dentin and Enamel.

Recurrent caries is still considered the main reason restorations need to be replaced. There are different materials available now that promise to reduce the possibility of recurrent caries by releasing fluoride and inhibiting restoration marginal caries. The purpose of this in vitro study was to evaluate the demineralization inhibition potential of a non-fluoride-releasing resin (Z100TM 3M, St. Paul, MN, USA) and a glass containing resin-based composite (Tetric EvoCeram Bulk Fill, Ivoclar/Vivadent AG, Schaan, Liechtenstein), which contains fluoride. Class V preparations were placed on 22 premolars; the gingival margin was below the cementoenamel junction and the occlusal margin was placed above the cemento-enamel junction. Ten teeth were randomly selected to be restored with Z100 while the other 10 were restored with Tetric EvoCeram Bulk Fill. Both groups were restored following manufacturer’s instructions. All teeth had an acid resistant varnish placed within one millimeter of the preparation margins. Both groups were placed in artificial caries challenge solution (pH 4.4). At the end of the 4 days; 100 µm buccolingual sections were obtained for each tooth; these were photographed under polarized light microscopy and the demineralized areas adjacent to the restorations were measured and quantified. The mean (±S.D.) area (µm2) of demineralization from the occlusal margin (enamel) and dentin margin were: Z100 2781.889 ± 1045.213; 3960.455 ± 705.964 and for Tetric EvoCeram Bulk Fill 1541.545 ± 1167.027; 3027.600 ± 512.078. Student’s t-test indicated that there was significantly less enamel and dentin demineralization adjacent to Tetric EvoCeram Bulk Fill compared to Z100; there was significantly less demineralization in enamel compared to dentin in both Tetric EvoCeral Bulk Fill and Z100. Tetric EvoCeram Bulk Fill performed better inhibiting demineralization at restoration margins when compared to Z100 and provided better demineralization inhibition in enamel than cementum/dentin.

Microleakage of high viscosity glass-ionomer and glass-carbomer with and without coating before and after hydrothermal aging

Objective: The objective of this study was to evaluate the microleakage patterns of GIC and GGC with and without their protective surface coatings on enamel and dentin margins before and after aging. Material and Methods: Two rectangular cavities (height: 2 mm; width: 3 mm; depth: 1.5 mm) were prepared on each tooth at the cemento-enamel junction were prepared on human permanent molars (N=56) and the teeth were randomly assigned to be restored with one of the following: a) high viscosity glass-ionomer cement (GIC) (EQUIA Fil, C Corp., Tokyo, Japan) (n=28), b) glass-carbomer cement (GCC) (Glass Carbomer Products, Leiden, The Netherlands) (n=28). Half of the teeth were further divided into two groups where one group received protective surface coating (SC) (G-Coat Plus, GC Corp) (n=14) and the other group did not (n=14). Half of the teeth were stored for 24 hours (n=7), and the other half was thermocycled (5000 cycles, 5-55°C) (n=7). For microleakage analysis, the teeth were immersed in 5% methylene blue dye for 24 hours, sectioned into two equal halves. Microleakage patterns were evaluated using stereomicroscope and scored on a scale of 0-3 (0: No dye penetration, 1: Dye penetration less than half of the axial wall, 2: Dye penetration more than half the axial wall, 3: Dye penetration spreading along the axial wall). Data were analyzed using Kruskal-Wallis tests at the significance level of 0.05. Results: Compared to 24 h storage, after thermocycling, surface coating on GIC decreased microleakage significantly compared to GCC (p=0.046) but not for GCC. In the thermocycled groups, coated GIC showed significantly less leakage at the enamel margin but no significant difference was found with both GIC and GCC in the dentin margins. Conclusion: The application of surface coating significantly reduced the microleakage scores of GIC but not GCC, within the enamel margins only.KeywordsGlass-carbomer; Glass-ionomer; Microleakage.

Comparison of micro-CT and conventional dye penetration for microleakage assessment after different aging conditions

AimThe aim of this study was to compare microleakage assessment by micro-tomography (micro-CT) and conventional microscopy in class V restorations after different aging treatments. MethodsClass V cavities were prepared in sound human molars and restored with composite (Filtek Supreme XTE) after application of a self-etch adhesive (Clearfil SE Bond). Sealing ability was evaluated by assessing silver nitrate penetration along enamel and dentin margins either by micro-CT or by conventional stereomicroscopy. Class V cavities were divided in three groups (each n = 5): control: no aging, thermocycling: 10,000 cycles, 5–55 °C; thermo-erosive cycling: thermocycling with concomitant storage in HCl (pH 2.1, 5 min, 6×/day, 8 days). Penetration of silver nitrate was quantified by micro-CT and stereomicroscopy (25-fold magnification). Data for silver penetration assessed by stereomicroscopy and micro-CT were checked for normality and analyzed by Pearson or Spearman correlations. Differences between the aging effects were analyzed by one-way ANOVA (enamel) or Kruskal-Wallis tests (dentin) (p< 0.05). ResultsFor enamel, the correlations between stereomicroscopy and micro-CT data were not significant. For dentin, silver penetration depths obtained by stereomicroscopy and by micro-CT were moderately correlated (r=0.54, p=0.039), while volume of silver penetration (micro-CT) was not significantly correlated with penetration depth of silver (stereomicroscopy). Thermo-erosive cycling mostly increased microleakage compared with the control group and restorations submitted to thermocycling. ConclusionsThermo-erosive aging increased the microleakage at enamel and dentin. The micro-CT analysis resulted in lower values of microleakage compared with the conventional stereomicroscope. Clinical significanceMicroleakage is often used to evaluate the interfacial integrity of adhesives with dental hard tissues. The micro-CT analysis underestimated the dye penetration compared with the assessments made by the conventional stereomicroscopy, leading to lower microleakage values.

Comparison of self-adhering flowable composite microleakage with several types of bonding agent in class V cavity restoration

The aim of the present study was to compare the marginal seal of self-adhering flowable composite resin with three universal bonding systems using the self-etch technique in Cl V cavities at enamel and dentin margins. In this in vitro study, Cl V cavities were prepared on the buccal surfaces of forty premolars, with the occlusal margin of each cavity on enamel and gingival margin on dentin. The teeth were divided into four groups (n = 10) in terms of the adhesive used; Group 1: Vertise Flow (VF) self-adhering composite resin, Group 2: Clearfil S3 Bond Universal (CS3BU), Group 3: G-Premio Bond (GPB), Group 4: Single Bond Universal (SBU). In Groups 2, 3, and 4, Z350 flowable composite resin was used to restore the cavities. After thermocycling, the samples were immersed in 10% methylene blue for 24 h and evaluated under a stereomicroscope after buccolingual sectioning; microleakage at enamel and dentin margins was recorded. Kruskal-Wallis and Mann-Whitney tests were used for statistical analyses. Statistical significance was set at P < 0.5. Vertis Flow self-adhering composite resin exhibited significantly higher microleakage at enamel and dentin margins compared to SBU and CS3BU; however, it had significantly less microleakage at enamel margin compared to GPB (P < 0.05). At the enamel and dentin margins, the minimum microleakage values were recorded at SBU and CS3BU margins, respectively. GPB exhibited the highest microleakage values among the groups evaluated and in all the groups, microleakage at dentin and enamel margins was significantly different (P < 0.05) except for SBU group. The marginal sealing ability of self-adhering flowable composite resin at enamel and dentin margins was poor compared to the majority of bonding agents evaluated.

Comparative evaluation of microleakage in Class V cavities restored with giomer, resin-modified glass ionomer, zirconomer and nano-ionomer: An In vitro study

Aims and Objective: Clinically, microleakage is the major cause for the failure of restorations in Class V cavities which may cause postoperative sensitivity and secondary caries. The newer generation of glass ionomers has been introduced in market with superior characteristics compared to conventional glass ionomers. The aim of this study was to evaluate the adaptability of new novel restorative material Nano-ionomer with resin-modified glass ionomer, Zirconomer, Giomer to tooth surface by measuring the degree of microleakage at gingival and occlusal restorative margins of Class V cavities and compare the same among the groups using stereomicroscopic study. Methodology: A total of 60 Class V cavities were prepared with occlusal margin in enamel, and the cervical margin in dentin and cementum of sound extracted premolars. Restorations were randomly assigned to one of the four groups (n = 15) and were restored with various type of glass ionomers (resin-modified glass-ionomer cements [RMGIC], Zirconomer, Giomer, Nano-ionomer), respectively. Specimens were thermocycled, immersed in Methylene blue dye, sectioned longitudinally and analyzed for leakage at the occlusal and cervical interfaces. Analysis of variance test, followed by post hoc Bonferroni Test was used to determine the inter- and intra-group difference and Paired t-test was used to determine the significant difference at enamel and cementum margins. Results: The intergroup comparison of occlusal and gingival scores showed a significant difference between RMGIC and Giomer, Zirconomer and Nano-Ionomer and Giomer and Nano-Ionomer (P

Shear bond strength and microleakage of novel glass-ionomer cements: An In vitro Study.

The overall success of dental restorations depends on the materials' ability to bond to dental structures and to eliminate the microleakage. Therefore, the aim of this study was to evaluate the shear bond strength (SBS) and microleakage of novel glass-ionomer restorative materials. In this study 62 intact molars were used, of which 30 molars were sectioned buccolingually, embedded in acrylic resin, and polished to obtain flat dentin surfaces. Then, glass-ionomer cylinders were built on the specimens (n = 15) with a high-viscosity glass-ionomer cement (GIC) (EQUIA Fil), a glass-carbomer (Glassfill), a zirconia-reinforced GIC (Zirconomer), or a conventional GIC (RivaSelfCure), and SBS testing was performed. For microleakage test, Class V cavities were prepared on buccal and lingual surfaces of the remaining 32 teeth and divided into four groups (n = 16). Each group was restored with one of four GICs and subjected to microleakage testing. The data were statistically analyzed (P = 0.05). The highest SBS values were observed in Glassfill group (P < 0.05). There were no significant differences on the SBS values of other three materials (P > 0.05). Regarding microleakage evaluations, no significant differences were observed at enamel margins (P > 0.05), whereas at dentin margins, EQUIA Fil and Zirconomer showed less microleakage than Glassfill (P < 0.05). Although the glass-carbomer restorative materials revealed higher SBS, other tested materials might be more reliable in clinical use, as they offer better leakage resistance.

Effect of Trypsin/EDTA Conditioning on Marginal Microleakage of Class V Composite Restorations Bonded With a One-Step Selfetch Adhesive

Background: Sodium hypochlorite and EDTA solutions are used in the preparation of dentin surfaces, which may increase the bond strength of the composite restorations and decrease their microleakage scores. This in-vitro experimental study aimed to assess the effect of dentin surface conditioning with EDTA/trypsin solution prior to bonding procedure with Clearfil S3 Bond on the microleakage of class V composite restorations. Methods: Class V cavities were prepared on the buccal and lingual surfaces of 18 human premolars (n=18) and randomly assigned into two groups. In the control group, Clearfil S3 Bond was applied on the dentin surfaces. While in the experimental group, before applying Clearfil S3 Bond, the surfaces were conditioned with EDTA/trypsin solution. The cavities on the teeth were then incrementally filled with Filtek Z250 light-cure composite. Afterward, all the samples were thermocycled for 500 cycles. Next, the specimens were immersed in methylene blue solution for 72 hours. The restorations were sectioned buccolingually through the center of the restorations with a diamond disk. Then, microleakage at the tooth- restoration interface was evaluated in the enamel and dentin margins blindly using dye penetration under a stereomicroscope at ×40 magnification. Finally, data were statistically analyzed by Mann-Whitney U test. Results: The results showed no significant differences between two groups regarding the microleakage scores of the enamel and dentin edges. In addition, in all sections and edges of the experimental group, decreased microleakage scores were attained compared to the control specimens (P<0.03). Conclusions: Regarding the limitations of the present study, the preparation of dentin surfaces with EDTA/trypsin solution before applying Clearfil S3 Bond resulted in the decreased microleakage scores compared to unprepared surfaces.

Efficacy of Direct Restorative Materials in Proximal Box Elevation on the Margin Quality and Fracture Resistance of Molars Restored With CAD/CAM Onlays.

The purpose of this study was to investigate the effect of four direct restorative materials that can be used in the proximal box elevation (PBE) technique. Seventy-five molar teeth were randomly assigned to one of five groups (n=15): type II glass ionomer (GI), type II resin-modified glass ionomer (RMGI), resin-based composite (RBC), bulk-fill (BF) resin-based composite, and a control with no box elevation procedure. Specimens were prepared for a standard mesio-occlusal-distal, computer-aided design/computer-aided manufactured (CAD-CAM) resin, nanoceramic onlay with mesial cervical margins located 1 mm above the cementoenamel junction (CEJ) and distal cervical margins located 2 mm below the CEJ. PBE was used to elevate the distal margins to 1 mm above the CEJ in all groups except the control group. For the control group the onlay margin was placed directly on the prepared distal tooth structure without PBE. A Lava Ultimate CAD/CAM resin, nanoceramic onlay restorative was manufactured and bonded on all specimens with RelyX Ultimate adhesive resin cement. The quality of the tooth-PBE material and PBE material-onlay interface was evaluated with scanning electron microscopy using epoxy resin replicas before and after cyclic loading (100,000 cycles, 1.2 Hz at 65N and 37°C). In addition to margin quality, the fracture resistance of each group was measured using a universal testing machine. Fracture pattern was recorded by visual examination. The Levene test for homogeneity and the Welch analysis of variance were completed for fracture resistance and margin quality. A χ2 test was completed for break mode. For dentin margins, a statistically significant difference was detected between the RMGI and control groups at baseline (p=0.0442). All other groups-GI, RBC, and BF-showed no difference from the control at baseline (p>0.05). No statistical significance was observed among groups for post-cyclic fatigue (p=0.8735). For onlay margins, no statistical significance was observed among groups for pre-cyclic fatigue, post-cyclic fatigue, or change (p=0.9713, p=0.528, p=0.4385, respectively). No significant difference was observed for the fracture resistance among groups or for the type of break by material used (p=0.1593, p=0.77, respectively). Within the parameters of this study, after mechanical fatigue, the materials used for PBE: RMGI, RBC, and BF, did not influence results in terms of margin quality and fracture resistance. Therefore, collective findings suggest that these materials might be suitable for PBE procedures. Nevertheless, clinical caution is recommended with any PBE procedure and further testing of GI materials is needed.

Kann ein bioaktives Füllungsmaterial die Sekundärkaries verhindern?

IntroductionThe ideal restorative material for children and adolescents with high caries risk should combine the fluoride release from glass-ionomer cements and the improved mechanical and physical properties of composite resins. Aim of the in vitro study is to test if a bioactive resin-modified glass-ionomer cement with continuous ion release (Ca++-, F–-, P–-), could influence formation of secondary caries, in a well-established, microbial caries model.Material and methodsA total of 48 class V cavities on freshly extracted 3rd molars were restored with i) “Activa Bioactive Restorative”, Pulpdent, ii) Fuji II LC, GC, iii) “total-etch adhesive Syntac”, Ivoclar + Filtek Supreme, 3M-ESPE, iv) “self-etch adhesive Futurabond M”, Voco + Filtek Supreme, 3M-ESPE, according to manufacturers’ directions. After 4 weeks storage in distilled water in 37 °C and thermocycling (10.000 cycles; 5 °C–55°C), specimens were loaded in the 10-day caries model (S. mutans [DSM 20523] 4 times/day for 1 hour). Demineralisation depth was evaluated via fluorescence microscopy (Nikon AZ 100 M, Nikon NIS-Elements).ResultsNo significant differences were noted between Activa (i) and Fuji (ii) (p > 0.05, Mann-Whitney). Activa (i) showed significantly lower demineralisation values at dentin margins, compared to both composite restorations (iii, iv), independent of the adhesive system used (p < 0.01, Mann-Whitney). No significant difference was noted between the groups for substance loss due to demineralisation or at enamel margins.ConclusionsApplication of the bioactive resin-modified glass-ionomer cement influenced the demineralisation values at dentin margins positively, and could be recommended as a caries-inhibiting material compared to composites.

Micro-computed tomography evaluation of microleakage of Class II composite restorations: An in vitro study.

Objective:The aim of this study is to investigate the microleakage attained with three resin-based material used to restore deep Class II cavities. A null hypothesis was chosen: there is no difference in microleakage among the tested materials.Materials and Methods:A total of 30 Class II cavities were prepared in freshly extracted molars with the proximal mesial and distal margins located, respectively, 1.5 mm apically and 1.5 mm coronally to the cementum-enamel junction. Restorations were completed using a three-step enamel-dentin adhesive system “Etch and Rinse,” margins were relocated using a micro-hybrid, preheated, or flowable composite and restorations were then completed using a conventional composite. All samples were coated with nail varnish with the exception of an area along the margins and apex was sealed using epoxide cement and then thermocycled (30-s dwell time, 5°C/55°C, 1000 cycles). A 50% ammoniac AgNO3 solution was used as tracer according to Tay's protocol. The microleakage analysis was performed using a microtomography system Sky-scan 1072 (SKYSCAN, Kartuizersweg 3B 2550, Konitch, Belgium).Results:The mean microleakage of all the tested materials showed greater leakage in the cementum margins; flowable composite exhibit greater leakage among the groups. Significant differences (P < 5%) within groups in both enamel and dentin margins were present. None of the tested materials eliminated marginal microleakage. Preheated composite showed significantly lesser microleakage.Conclusion:Tested materials showed statistical differences in microleakage; thus, the null hypothesis has been rejected. Within the limitations of the present experimental procedure, it can be concluded that flowable resin composite should be avoided at the dentin/cementum margin.

The effects of self-etch bio-active dental adhesive systems on bacterial microleakage

The aim of this in vitro study was to evaluate the effects of bio-active and non-bio-active self-etch adhesive sytems on bacterial microleakage of class II box cavities with restoration margins in dentin. Two bio-active (Clearfil Protect Bond and F1 Bond II) and two nonbio-active (Clearfil SE Bond and Clearfil s3 Bond) adhesive systems were selected for the study. Eighty mesial and distal class II box cavities were prepared on fourty sound human third molar teeth. The teeth were then divided into four groups with 10 teeth in each group. Groups were restorated using different adhesive systems. The restored specimens were immersed into a culture medium containing streptococcus mutans for bacterial microleakage test. Serial sections of the specimens were used to evaluate the bacterial lekage by using light microscope. The data obtained from the test of bacterial microleakage was evaluated using 2-way mixed analysis of variance (p < 0.05). Statistical analysis showed significant differences between the groups (p < 0.05). Nevertheless it was observed that none of the tested adhesive systems including the bio-active ones were successfull in eliminating bacterial microleakage.

Flowable composites for restoration of non-carious cervical lesions: Results after five years

ObjectivesTo evaluate the clinical performance of two flowable composites for restoration of Class-V non-carious cervical lesions (NCCLs), one with novel (N’Durance® Dimer Flow, Septodont; ND) and one with modified conventional matrix composition (Filtek™ Supreme XTE Flow, 3M-ESPE; FS). The null hypothesis was that both flowable composite materials perform equally regarding clinical quality and survival. Methods50 patients received one ND and one FS restoration of NCCLs in premolars using Clearfil Protect Bond (Kuraray) as an adhesive without additional selective enamel etching. Restorations were evaluated at baseline (BL), after 30 and 60 months employing selected original FDI criteria and refined FDI criteria by separate evaluation of enamel and dentine margins. Non-parametric statistical analyses and χ2 tests were applied (α=0.05). Results38 patients with both restorations under risk were available for the 60-mo recall (recall rate: 76%). At 60-mo, 94.7% of ND and 84.2% of FS restorations were rated clinically acceptable. No significant differences for all selected FDI criteria were recorded between ND and FS at each examination time point except for the criteria surface lustre at 60-mo, where FS showed significantly better results. No significant differences over time could be detected for both materials. There was a trend for more deterioration along the enamel margins than along the dentine margins (criteria marginal staining and marginal adaptation). SignificanceWithin the limitations of the study, the null hypothesis that materials perform equally could not be rejected. Both flowable composites performed similarly regarding clinical performance.

The micromorphological characterization of adhesive bond in dentin different locations

The aim of this study was to analyse the interfacial micromorphology of total-etch adhesives and dentin structures different locations by using SEM. Standardized cylindrical cavities (3mm in diameter, 2mm deep) with all margins in dentin were prepared on occlusal and buccal surfaces of twenty extracted human third molars. A total-etch dentin adhesive system and a light-cure flowable composite (Filtek Ultimate Flowable, 3M ESPE, St. Paul, MN, USA) were used in this study. Micro-morphological SEM analysis of the marginal seal of the original tooth specimens was performed using high magnification of up to 1000×. In this study, we found the difference in interfacial micromorphology in dentin different locations. Also, marginal gap was found in both observed dentin area. Better understanding of complexity and three- dimensional variations of the tooth structure is important for prevention of clinical challenges such as postoperative sensitivity, marginal discoloration and secondary caries, which could be prevented by achieving of predictable and long-lasting adhesive bond.

Glass ionomer cement inhibits secondary caries in an in vitro biofilm model.

The objective of this study was to investigate the effect of different glass ionomer cements on secondary caries inhibition in a fully automated in vitro biofilm model. One hundred and twenty-four extracted third molars received class V cavities and were filled with one conventional (Ketac Molar/KM), and two resin-modified glass ionomer cements (Photac Fil/PF, Ketac N100/KN, 3M Espe). A bonded resin composite (Single Bond Plus/Filtek Supreme XTE) served as control. After 14days water storage at 37°C, specimens were thermocycled (10,000×5/55°C). Over a period of 10days, specimens were subjected to cariogenic challenge for 3/4/6h/day. Demineralization was caused by Streptococcus mutans (DSM 20523) alternatingly being rinsed over specimens using artificial saliva. After biological loading, teeth were cut longitudinally and demineralization depths were evaluated at the margins and at a distance of 0.5mm from the margins using fluorescence microscopy. Marginal quality was investigated under a SEM at ×200 magnification. Four-hour demineralization depths were for enamel margins (EM), enamel (E), dentin margin (DM), and dentin (D) (μm±SD): KM: EM 12±8, E 33±7, DM 56±11, D 79±6; PF: EM 19±13, E 34±13, DM 53±10, D 77±12; and KN: EM 26±5, E 38±6, DM 57±11, D 71±7. For all glass ionomer cements (GICs), demineralization depth at the margins was less compared to 0.5mm distance, with demineralization depth having been correlated to duration of cariogenic challenge (ANOVA [mod. LSD, p<0.05]). Compared to the bonded resin composite, all GICs exhibited caries inhibition at restoration margins in enamel and dentin. Fluoride-releasing GIC materials exhibit a secondary caries inhibiting effect in vitro. Glass ionomer cements have a higher secondary caries inhibiting effect than resin composites.

Microleakage and Shear Bond Strength of Composite Restorations Under Cycling Conditions.

The aim of this study was to evaluate microleakage and shear bond strength of composite restorations under different cycling conditions. Class V cavities were prepared in the buccal and lingual surfaces of 30 human molars (n=60). A further 60 molars were used to prepare flat enamel and dentin specimens (n=60 each). Cavities and specimens were divided into six groups and pretreated with an adhesive (self-etch/Clearfil SE Bond or etch-and-rinse/Optibond FL). Composite was inserted in the cavities or adhered to the specimens' surfaces, respectively, and submitted to cycling (control: no cycling; thermal cycling: 10,000 cycles, 5°C to 55°C; thermal/erosive cycling: thermal cycling plus storage in hydrochloric acid pH 2.1, 5 minutes, 6×/day, 8 days). Microleakage was quantified by stereomicroscopy in enamel and dentin margins after immersion in silver nitrate. Specimens were submitted to shear bond strength testing. Statistical analysis was done by two-way analysis of variance and Kruskal-Wallis tests (p<0.05). Microleakage in enamel margins was significantly lower in the control group compared with thermal cycling or thermal/erosive cycling. Erosive conditions increased microleakage compared with thermal cycling (significant only for Clearfil SE Bond). No significant differences were observed in dentin margins. Bond strength of enamel specimens was reduced by thermal cycling and thermal/erosive cycling when Clearfil SE Bond was used and only by thermal/erosive cycling when Optibond FL was used. No differences were observed among dentin specimens. Thermal/erosive cycling can adversely affect microleakage and shear bond strength of composite resin bonded to enamel.

Effect of Chlorhexidine and Ethanol on Microleakage of Composite Resin Restoration to Dentine.

To evaluate the effect of chlorhexidine and ethanol on microleakage of composite resin restoration to dentine. Class II cavities with dentinal margin were prepared on 96 premolar teeth. All specimens were acid-etched, rinsed and dried. Then the samples were randomly divided into four groups according to pre-treatment of the dentine: no treatment (control group); treatment with 100% ethanol for 60 s (group 2); treatment with 2% chlorhexidine for 60 s (group 3); 100% ethanol for 60 s and then 2% chlorhexidine for 60 s (group 4). After dentine treatment, each group was bonded and restored with a universal micro hybrid composite resin, according to the manufacturers' recommendation. Microleakage was evaluated by dye extraction method in two subgroups, immediately (24 h) and after 6 months in storage. Scan electronic microscope analyses for two samples of each group were also conducted. Data were analysed by two-way analysis of variance and Tukey test. The lowest and the highest amount of microleakage were observed in the ethanol group and in the control group, respectively. There were significant differences in microleakage among the groups (P = 0.003) and between measurement times (P = 0.001). For each storage time, the control group showed significant differences from the other groups and there were no differences between the other groups. Ethanol-wet bonding and chlorhexidine application may have potential benefits in lowering the occurrence of microleakage in the long term.

Comparison of microleakage of Scotchbond™ Universal Adhesive with methacrylate resin in Class V restorations by two methods: Swept source optical coherence tomography and dye penetration.

One of the most important factors in restoration failure is microleakage at the restoration interface. Furthermore, a new generation of bonding, Scotchbond Universal (multi-mode adhesive), has been introduced to facilitate the bonding steps. The aim of this study was to compare the microleakage of Class V cavities restored using Scotchbond™ Universal with Scotchbond Multi-Purpose in two procedures. Eighteen freshly extracted human molars were used in this study. Thirty-six standardized Class V cavities were prepared on the buccal and lingual surfaces. The teeth were divided into three groups: (1) Group A: Scotchbond Universal with "self-etching" procedure and nanohybrid composite Filtek Z350. (2) Group B: Scotchbond Universal with "total etching" procedure and Filtek Z350. (3) Group C: Scotchbond Multi-Purpose and Filtek Z350. Microleakage at enamel and dentinal margins was evaluated after thermocycling under 5000 cycles by two methods of microleakage assay: swept source optical coherence tomography (OCT) and dye penetration. Wilcoxon's signed-rank test and Kruskal-Wallis test were used to analyze microleakage. In silver nitrate dye penetration method, group A exhibited the minimum microleakage at dentin margins and group C exhibited the minimum microleakage at enamel margins (P < 0.05). Furthermore, in OCT method, group C demonstrated the minimum microleakage at enamel margins (P = 0.047), with no difference in the microleakage rate at dentin margins. Scotchbond Universal with "self-etching" procedure at dentin margin exhibited more acceptable performance compared to the Scotchbond Multi-Purpose with the two methods.

In vitro microleakage of class v composite restorations prepared by Er,Cr:YSGG laser and carbide bur

Background: The aim of this in vitro study was to compare the degree of microleakage on enamel and dentin margins of class V cavities prepared with either a high-speed drill or an Er,Cr:YSGG laser (2780 nm) and to associate their use with a beveling method for the margin. Method and Materials: Sixty bovine incisors were randomly distributed into three groups. Group 1 (G1) cavities were laser prepared and bur beveled, group 2 (G2) cavities were bur prepared and beveled, while cavities of group 3 (G3) were laser prepared and beveled. Cavities were restored with selective enamel etching, using the same bonding agent and nano-hybrid resin composite for all groups. After thermocycling, microleakage was assessed using a methylene blue dye penetration method. Results: Statistical analysis (Mann-Whitney, Kruskal-Wallis and post-hoc Dunn’s multiple comparison tests) demonstrated significantly higher microleakage for dentin compared to enamel margins in G1. Enamel margin microleakage was found to be significantly higher at G3 compared to G1 (p=0.032) and G2 (p=0.001), while no significant differences were found between G1 and G2 (p=0.850). Regarding dentin margins, G2 group performed significantly better than G1 and G3 (p&lt;&lt;0.001), while there was no significant difference among G1 and G3 scores (p=1.000). Conclusions: The conventional cavity preparation method seems to perform better in terms of microleakage than the Er,Cr;YSGG laser. Laser-prepared cavities could perform better in terms of microleakage if an additional step of enamel bur-beveling is performed prior to restoration.