Dentin Microleakage Research Articles

The Impact of Adhesive-Containing Nanoparticles of ZrO2and TiO2 on Antimicrobial Effectiveness, the Strength of Bonding, and the Extent of Microleakage in Dentin Affected by Caries

Aims: Zirconium oxide (ZrO2) and Titanium dioxide (TiO2) nanoparticles (NPs) in-cooperated in a three-step etch and rinse adhesive against Lactobacillus survival rate, shear bond strength (SBS) and marginal leakage on CAD. Methods: Ninety premolars having occlusal carries to the middle third of the dentin were included. Inoculation of Lactobacillus on CAD surface was performed on 30 samples. The remaining 60 samples were then divided into three groups based on primer applied in three steps etch and rinse (n = 20) Group 1 (Optibond FL), Group 2: (Optibond FL + TiO2), and Group 3: (Optibond FL + ZrO2). The survival rate was assessed on the 30 samples. The remaining 60 samples were applied with Optibond FL bonding agent and composite restorative material. Microleakage, SBS, and failure mode were analyzed. The means and standard deviations (SD) were compared utilizing ANOVA followed by a post hoc Tukey multiple comparison test. Results: Specimens in Group 1 demonstrated the maximum numbers of Lactobacillus species and marginal leakage values. Group 2 specimens displayed the minimum count of bacteria, lowest microleakage scores, and highest bond values. However, Group 1 specimens showed the lowest bond integrity. Conclusions: ZrO2 and TiO2 NPs filled dental adhesive demonstrated better antimicrobial efficacy and bond strength. They also cause a reduction in marginal leakage at the resin dentin interface.

Desensitizing toothpastes for dentin sealing and tertiary dentin formation in vitro and in vivo: a comparative analysis

BackgroundDentin hypersensitivity is a painful response to external stimuli applied to exposed dentinal tubules. Various toothpastes with active desensitizing ingredients for the relief of dentin hypersensitivity are commercially available. However, data from several studies suggest that the effects of desensitizing toothpastes are unstable and brief. This study aimed to investigate the effect of toothpastes containing CPNE7-derived oligopeptide (CPNE7-DP) and other active desensitizing ingredients in the dentin microleakage, tubule occlusion and tertiary dentin formation.MethodsUsing scanning electron microscopy (SEM), we evaluated the patency of dentinal tubules on the surface of human dentin disks after brushing experiments with the various toothpastes. Dentin was histologically evaluated in a hypersensitivity model of canine teeth, after the exposed dentin area was brushed for 6 weeks. The toothpaste used in group 1 (control) did not contain any desensitizing ingredients; that used in group 2 contained CPNE7-DP; Colgate Sensitive was used in group 3; and Sensodyne Rapid Relief was used in group 4. Finally, we conducted microleakage analysis to investigate the dentin sealing effect. The microleakage analysis data were subjected to one-way ANOVA and post-hoc Tukey tests (alpha = 0.05).ResultsIn the SEM images, all four groups of teeth exhibited partial occlusion of the dentinal tubules on the tooth surface. In the in vivo hypersensitivity model, group 2 exhibited a newly formed tertiary dentin, whereas no new hard tissue formation was observed in groups 1, 3, and 4. Microleakage analysis revealed that the volume of dentinal fluid flow was significantly smaller in group 2 than in group 1.ConclusionsThese results indicate that CPNE7-DP is a promising active ingredient with long-term dentin sealing effects.

The effects of amalgam contamination and different surface modifications on microleakage of dentin bonded to bulk fill composite when using different adhesive protocols

BackgroundTo evaluate the effect of amalgam contamination, different surface treatments, and adhesive protocols on dentin microleakage to bulk-fill composite resin material.MethodsForty teeth were fixed in (polyvinyl siloxane) PVS molds, and the Class II cavities were placed on mesial and distal aspects. Thirty teeth were restored by amalgam and thermocycled to 10,000 cycles (5 and 55 °C, 30-s dwell time). The rest were restored with Filtek one Bulk Fill composite without amalgam predecessor. Samples were divided into: G1 (dentin pretreated with 2% chlorhexidine gluconate), G2 (0.5 mm of dentin was removed), G3 (no surface modification), and G4 (control, where composite was bonded to sound dentin without amalgam predecessor.). Single Bond Universal Adhesive system was used to bond the composite material, by using the etch-and-rinse protocol in the mesial cavity preparation and self-etch protocol in the distal. Specimens underwent thermocycling for 5000 cycles, then embedded in silver nitrate and sectioned for stereomicroscope examination. Descriptive statistics, Mann–Whitney U test, and Kruskal–Wallis test were used to analyze the results at p < 0.05.ResultsThe highest microleakage score values (4.00) were found in the G2, and G4 in etch-and-rinse protocol. While the lowest scores were found in G2 when using self-etching protocol (1.5). Lower microleakage values were associated with the chlorhexidine treatment group for both adhesive protocols. No significant differences were found between amalgam contaminated and non-contaminated groups.ConclusionsAmalgam contamination did not affect microleakage. Self-etching adhesive protocol significantly reduced microleakage for all groups irrespective of the surface treatment. Chlorhexidine pretreatment improved microleakage for both adhesive protocols but had no significant effect.

Marginal microleakage and modified microtensile bond strength of Activa Bioactive, in comparison with conventional restorative materials.

This study aimed to assess the enamel and dentin marginal microleakage and dentin microtensile bond strength (μTBS) of ACTIVA BioACTIVE Restorative with and without a bonding agent compared with conventional restorative materials. For enamel and dentin microleakage, Class II boxes were prepared in the mesial (1 mm under the cementoenamel junction) and distal (1 mm above the cementoenamel junction) surfaces of 90 extracted human third molars. The teeth were randomly divided into five groups (n = 18): Group Z (G-Premio Bond + Filtek Z250 XT), Group X (G-Premio Bond + X-tra fil bulk-fill), Group AA (G-Premio Bond + Activa Bioactive restorative), Group A (Activa Bioactive restorative), and Group G (dentin conditioner + Fuji II LC Improve). The teeth were thermocycled, and their microleakage was quantified using the dye penetration test under a stereomicroscope. For dentin μTBS measurement, 12 specimens were fabricated in metal molds (1 × 1 × 12 mm³) for each group mentioned above, and a universal testing machine measured their μTBS. Data were analyzed using one-way analysis of variance (ANOVA), the Kruskal-Wallis test, and multiple comparisons tests. Significant differences were noted among the groups in marginal microleakage and μTBS (p < .001). The highest mean microleakage scores at the enamel and dentin margins were noted in Group A, which had significant differences with other groups (p < .001). The highest μTBS was found in Group X, with significant differences with Group G and Group A (p < .05). The lowest µTBS was noted in Group A, with significant differences with Groups X, Group AA, and Group Z (p < .001). Activa Bioactive without a bonding agent showed significantly lower µTBS to dentin, and higher microleakage at the enamel and dentin margins. Application of adhesive resin with Activa Bioactive provided a dentine bond strength and marginal seal comparable to other restorative materials.

Comparison of Dentinal Microleakage in Three Interim Dental Restorations: An In Vitro Study.

The aim of this study was to assess and compare the coronal microleakage of e-Temp (DiaDent, Korea), intermediate restorative material (IRM) (Dentsply, Sirona), and Systemp Inlay (Ivoclar Vivadent, Germany) temporary restorative materials used to seal the class I cavity preparations. In this in vitro experimental study, three temporary restorative materials were assessed for microleakage. A standardized class I access cavities (2 mm × 4 mm) were prepared in 30 freshly extracted intact human premolar teeth. Teeth were then divided randomly into three groups consisting of 10 samples each. Teeth were restored with e-Temp (n = 10), IRM (n = 10), and Systemp Inlay (n = 10), temporary restorations, and subjected to thermocycling 5000 times in a cold bath followed by a temperature of 55°C with a dwell time of 30 seconds. Teeth were painted with two layers of nail polish except for 1 mm around the restoration margin, soaked in 1% methylene blue dye solution (pH 7.4), and kept for 24 h. Sticky wax was used to seal the apical foramina. All the teeth were sectioned mesiodistally, and the specimens were examined for the amount of dye penetration (microleakage) through the restoration using Digital Microscope under 50× magnification. Data were analyzed using descriptive statistics, Mann-Whitney U, and Kruskal-Wallis tests. e-Temp showed 1 (10%) specimen with dye penetration up to 1 mm (Score 1). The specimens restored with IRM showed a 1 (10%) and 9 (90%) of scores for 1 and 3 dye penetration. However, 2 (20%) teeth restored with Systemp Inlay showed a dye penetration up to 3 mm or more (Score 3). A comparison of mean microleakage values of e-Temp (0.03 ± 0.10), IRM (2.69 ± 0.77), and Systemp Inlay (0.78 ± 1.64) showed a statistically significant difference (P < 0.001). IRM specimens showed significantly higher microleakage values than e-Temp and Systemp Inlay specimens (P < 0.05). All the temporary restorative materials tested in this in vitro experiment showed a certain extent of microleakage. The temporary restorative material e-Temp showed the least microleakage values followed by Systemp Inlay and IRM.

In Vitro Study on the Adhesive Performance of Some Resin-Based Materials Used to Restore Class II Cavities.

The study aimed to evaluate the adhesive performances of two ormocer materials and two micro-hybrid composites placed to restore class II cavities. We tested the null hypothesis, which considered that the adhesive behaviors of tested materials did not differ. On each extracted tooth, two class II cavities were prepared having an enamel located cervical margin and a cementum located cervical margin, respectively, and were restored using two different restoration techniques. The teeth followed a tooth impregnating protocol and were sectioned and evaluated by optical microscopy to highlight the marginal microleakage around restorations. Cervical and occlusal microleakage as well as microleakage ratios were calculated. The microleakage test showed that all tested materials exhibited some degree of dentinal microleakage both on cervical and occlusal areas irrespective of the restoration technique. Some significant differences were recorded in adhesion performance of the materials. The cervical microleakage ratio was significantly increased for one of the micro-hybrid resin composites in comparison with one of the ormocer materials (p = 0.0159). Significantly differences were observed in occlusal microleakage ratios when the two micro-hybrid composites were compared (p = 0.047). The results failed to reject the null hypothesis. The present study could not demonstrate the superiority of ormocer-materials relative to conventional composites.

Adhesion of Flowable Resin Composites in Simulated Wedge-Shaped Cervical Lesions: An In Vitro Pilot Study

The resin composite restoration of non-carious cervical lesions (NCCLs) still faces some drawbacks mostly related to the quality of the marginal seal. This study attempts to evaluate the adhesive capacities of two flowable and two conventional hybrid resin composite restorations of NCCLs having two types of cervical margins. Our null hypothesis assumes the same adhesive behavior of different materials. The relative composition of dental–restoration structures was also measured. Thus, restored wedge-shaped cervical cavities were realized on both the buccal and oral surfaces of extracted teeth. After immersion in dye solution, sectioning of the teeth was performed. We proposed an optical microscopy method to quantify the dye penetration along the restoration–tooth interface and scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDX) to evaluate the quality of the peripheral seal. The data obtained revealed an amount of dentinal microleakage for all tested materials, despite the favorable results of the restoration peripheral seal. Therefore, data from this study failed to reject the null hypothesis. The adhesion is not influenced by the position of cervical margins. The SEM revealed occasional disruptions of the adhesive interface. EDX sustains the qualitative compositions as provided by the manufacturers. Conclusions: The four experimental composites are recommended to restore NCCLs in clinic.

Sistemas de fotoativação e seus impactos nas restaurações em resina composta: uma revisão de literatura

As substâncias fotoiniciadoras e os aparelhos de fotoativação estão diretamente ligados ao desempenho físico-mecânico e químico das resinas compostas. Devido à coloração amarelada proveniente da canforoquinona (CQ), os fotoiniciadores alternativos têm sido usados de forma complementar ou substituta. Assim, o objetivo do presente estudo foi desenvolver uma revisão da literatura sobre os fotoiniciadores em correlação com a fotoativação e seus impactos nas restaurações em resina composta. A revisão da literatura foi conduzida a partir de buscas nas bases de dados Scielo, PubMed e Google Acadêmico através dos descritores: resinas compostas, polimerização e fotoiniciadores. Na busca realizada no período entre Março e Junho de 2020, dos 42 artigos encontrados, 37 artigos foram utilizados. Dentre as variações dos sistemas fotoiniciadores, observou-se que no geral, elas apresentaram pontos positivos como bom desempenho físico-mecânico e químico com a avaliação do grau de conversão, resistência flexural e microdureza. Assim como apresentaram também pontos negativos como alta toxicidade, formações de gaps e índices insatisfatórios de microinfiltração em dentina. Em relação aos sistemas de fotoativação, os diodos emissores de luz (LEDs), chamados de polywave trouxeram vantagens por possuírem alta irradiância, alto grau de colimação do feixe luminoso, e emitirem um espectro de onda maior, que atinge a cor violeta, necessária para ativar a reação química de polimerização dos fotoiniciadores alternativos. Pode-se concluir que o surgimento das novas substâncias fotoiniciadoras e os aparelhos polywave estabelecem certa harmonia com a capacidade de fornecimento de luz, a reação das substâncias e o alcance das propriedades físico-mecânicas fornecidas por elas.

A Comparative Study of Cervical Composite Restorations Microleakage Using Dental Universal Bonding and Two-step Self-etch Adhesive

The aim of this study is to compare microleakage of cervical restorations using universal bonding and two-step self-etch adhesive with or without enamel etching through a dye penetration testing method. In this in vitro experimental study, 70 maxillary premolar teeth with no anomaly or decay were randomly divided into five groups of 14. Conventional cervical cavities were prepared with diamond bur on the facial surface of the teeth. The teeth were prepared using G-Premio Bond/self-etch technique, G-Premio Bond/total-etch technique, G-Premio Bond/selective-etch technique, Clearfil SE Bond/self-etch technique, and Clearfil SE Bond/selective-etch technique in Groups I to V, respectively, and restored with composite. Microleakage at the occlusal enamel margin and the cervical dentinal margin was ranked from 0 to 4 based on dye penetration using stereomicroscope (×32). Statistical analysis was carried out using Kruskal-Wallis and Mann-Whitney tests at a significance level of α = 0.05. The mean occlusal microleakage in the five study groups was 1.07, 0.57, 0.57, 1.28, and 0.78, respectively. The mean cervical microleakage was 0.97, 0.85, 0.64, 1.35, and 1.14, respectively. Kruskal-Wallis test showed significant difference between the microleakage scores of different groups in enamel (p = 0.022) and dentin (p = 0.01). Clearfil SE Bond/self-etch technique group showed the highest mean score of microleakage in enamel margins, and G-Premio Bond/total-etch technique and G-Premio Bond/selective-etch technique groups showed lowest enamel microleakage mean. Clearfil SE Bond/self-etch group showed the highest mean score of microleakage in dentin margins, while G-Premio Bond/selective-etch technique group showed the lowest mean score of dentin microleakage. Selective etching of enamel will decrease enamel microleakage. G-Premio Bond shows better microleakage results in comparison to Clearfil SE Bond in dentinal margins. A major problem in cervical composite restorations is the presence of microleakage in the cervical wall. Different adhesive systems have been designed to overcome this problem.

An in vitro evaluation of microleakage of resin based composites bonded to chlorhexidine-pretreated dentin by different protocols of a universal adhesive system

PurposeThis study compared microleakage of different resin based composite (RBC) materials bonded to dentin, after chlorhexidine (CHX) application, by different adhesion protocols of a universal adhesive system. MethodsClass V cavities were prepared on the buccal and lingual surfaces of 40 premolar teeth. The “etch-and-rinse” technique of a universal bond adhesive system (Single Bond Universal Adhesive) was used on buccal preparations, while the “self-etch” protocol was used on the lingual surfaces. Two RBCs, one bulk fill (Filtek Bulk Fill [FBF]) and one conventional (Filtek Z350 XT [Z350XT]), were used. Teeth were divided into two groups of 20 teeth each, 10 per each RBC (n = 10): (1) control; and (2) pretreatment with 2% CHX. For FBF groups, teeth were restored with a single increment; however, for Z350XT, a layering technique was used. Teeth were aged by thermo-cycling and prepared for microleakage testing. Dye penetration was evaluated and scored from 0 to 4. Data were analyzed at a significance level of P < 0.05. ResultsThe highest microleakage mean scores were found in the control group of the etched margins for both RBCs (2.80 ± 1.033 FBF and 2.10 ± 1.370 Z350XT). The CHX-pretreated group showed significantly lower microleakage than the control for FBF only (P = 0.008). No significant difference was found between groups for the “self-etch” protocol (χ2 = 0.884, P = 0.08). No significant differences were found between FBF and Z350XT in all study groups (P > 0.2). ConclusionsWhen the “self-etch” protocol of the universal adhesive system was used, dentin microleakage was not affected by CHX-pretreatment when teeth were restored with bulk fill or conventional RBCs. In the “etch-and-rinse” protocol, CHX application improved the marginal seal before restoration with bulk fill material. However, in the absence of CHX, the “etch-and-rinse” protocol negatively affected marginal integrity.

Does laser etching have an effect on application mode of a universal adhesive?-A microleakage and scanning electron microscopy evaluation.

This study aimed to evaluate the microleakage of a universal adhesive's different application modes incorporated with Er,Cr:YSGG laser on Class V resin composite restorations. Sound human molar teeth (n = 30) were used for microleakage evaluations. Specimens with 60 standardized Class V cavities were divided into five groups according to the adhesive modes of universal adhesive, Adhese Universal (n = 12). Group 1-etch-and-rinse mode with phosphoric acid; Group 2-etch-and-rinse mode with Er,Cr:YSGG laser; Group 3-selective-etch mode with phosphoric acid; Group 4-selective-etch mode with Er,Cr:YSGG laser; Group 5-self-etch. After restorations were performed with a resin composite, Tetric N-Ceram, the specimens were polished and subjected to thermocycling (10,000X). Following immersion in 0.5% basic fuschin for a day, the teeth were sectioned and the degree of microleakage was determined along the tooth-resin composite interface using a light microscopy(40X). Five specimens from each group were examined by scanning electron microscopy. The Kruskal-Wallis, Siegel Castello, and Wilcoxon tests were used for statistical analyses (α = .05). At the enamel margins, significant differences were obtained among the groups (p < .05). Significantly higher microleakage scores were detected in Group 5 in comparison with Groups 1, 2, and 3. There were no significant differences between different adhesive strategies at the dentin margins (p > .05). While analyzing enamel and dentin microleakage scores, no statistically significant differences were observed in Groups 4 and 5 (p > .05). The laser application time and the adhesive modes of universal adhesives could affect the microleakage at the enamel margins. Different adhesive modes of universal adhesives combined with laser etching had no influence on the microleakage scores of dentin margins.

Investigations on the adhesion of new composites for restoring cervical lesions using energy dispersive X-ray analysis and scanning electron microscopy

Restoration of noncarious cervical lesions with resin composites is one of the treatment options, but the retention of the restorations located at the crown-root junction is still a cause of clinical concern. The aim of this study was to evaluate the adhesive properties of three experimental resin composites and two commercial materials used to restore cavities prepared on extracted teeth as well as to determine the relative elemental composition of these materials. We tested the null hypothesis, which considered that the adhesive behaviours of different resin composites did not differ. The microleakage test using tracers showed that all tested materials exhibited some degree of dentinal microleakage, although they all had good dentinal adhesion. The results failed to reject the null hypothesis. The scanning electron microscopy revealed completely adapted adhesive interfaces underneath the restorations along with well-developed hybrid layers depending on the adhesive system. Energy dispersive X-ray analysis analyses showed that the restorative materials have similar chemical compositions, with some differences between the samples from the same material. The results support the implementation of experimental resins in clinical settings.

The role of surface-sealant application on bond effectiveness of all-in-one self-etch adhesives

Purpose: To examine microleakage around Class-V restorations bonded with 3 current all-in-one adhesive systems in the presence or absence of surface-sealant in different evaluation groups.Materials and Methods: Clearfil S3 Bond, G-Aenial Bond, and Optibond All-in-One (AiO), were used in the Class-V cavities in accordance with the manufacturer’s instructions (control group) or were additionally combined with Fortify Plus surface-sealant (surface-sealant group). The two main treatment groups of the dentin adhesives were subdivided into four different evaluation groups (24 h, 6 months, 12 months, and 12 months with two applications); the teeth were immersed in 0.5% methylene blue dye solution for 24 h. Samples were then sectioned longitudinally in a bucco-lingual direction and evaluated for microleakage under a stereomicroscope. Dye penetration was scored at the enamel (occlusal) and dentin (gingival) margins.Results: Microleakage scores were greater at the dentin margins compared with the enamel margins for Clearfil S3 Bond in all evaluation groups, whereas no difference was observed between enamel and dentin microleakage for Optibond AiO. Using Fortify Plus in the enamel margins decreased the microleakage scores of Clearfil S3 Bond. When the control and surface-sealant groups were compared in the G-Aenial Bond enamel margins, the application of surface-sealant significantly reduced microleakage after 6 and 12 months. For Optibond AiO, no statistically significant differences in enamel and dentin margins were observed between the control and surface-sealant application groups.Conclusion: The application of surface-sealant could be considered appropriate for reducing microleakage in composite resin restorations, but this effect might depend on the dentin adhesive.

Marginal integrity of low-shrinkage and methacrylate-based composite resins: Effect of three different hemostatic agents.

BackgroundMoisture control is very important in restorative procedures in dentistry. Use of hemostatic agents helps control moisture; however, they might result in changes on enamel and dentin surfaces, affecting composite resin bond quality. The aim of this in vitro study was to evaluate the marginal microleakage of two different composite resins with the use of three different hemostatic agents.Material and MethodsStandardized Class V cavities were prepared on the buccal and lingual surfaces of 48 premolars with cervical margins 1 mm apical to the cementoenamel junction (CEJ). The samples were randomly divided into 8 groups. In groups 1 to 4, an etch-and-rinse adhesive (Adper Single Bond) was applied as the bonding system, followed by exposure to different hemostatic agent: group 1: no hemostatic agent (control); group 2: ViscoStat; group 3: ViscoStat Clear; and group 4: trichloracetic acid, as hemostatic agents. The cavities were restored with Z-250 composite resin. In group 5 to 8 Silorane System Adhesive (Filtek P90 Adhesive) was applied as a bonding agent, followed by exposure to different hemostatic agents in a manner similar to that in groups 1to 4. The cavities were restored with Filtek P90, a low-shrinkage composite resin. The samples in each group were evaluated for dye penetration under a stereomicroscope at ×36 after 24 hours and a 500-round thermocycling procedure at enamel and dentin margins. Statistical analysis was carried out using Kruskal-Wallis and Mann-Whitney tests (α=0.05).ResultsZ-250 composite resin exhibited significantly higher dentin microleakage scores compared to Filtek P90 (P = 0.004). Trichloracetic acid increased dentin microleakage with Filtek P90 (P=0.033).ConclusionsUnder the limitations of this in vitro study, application of hemostatic agents did not affect microleakage of the two tested composite resins except for trichloracetic acid that increased marginal microleakage when used with Filtek P90. Key words:Composite resin, dental leakage, hemostatics, silorane system adhesive.

Sealing of adhesive systems in ferric sulfate-contaminated dentinal margins in class V composite resin restorations.

Background. Hemostatic agents are applied to prepare an isolated bleeding-free condition during dental treatments and can influence adhesive restorations. This study evaluated the effect of a hemostatic agent (ViscoStat) on microleakage of contaminated dentinal margin of class V composite resin restorations with three adhesives.Methods. Sixty freshly extracted human molars were selected and class V cavities (3×3×1.5 mm) were prepared on buccal and lingual surfaces. Gingival margins of the cavities were placed below the cementoenamel junction. The teeth were divided into six groups randomly. The adhesives were Excite, AdheSE and AdheSE One. In three groups, the gingival walls of the cavities were contaminated with ViscoStat and then rinsed. The cavities were restored with composite resin and light-cured. After storage in distilled water (37°C) for 24 hours and polishing, the samples were thermocycled and sealed with nail varnish. Then they were stored in 1% basic fuchsin for 24 hours, rinsed and mounted in self-cured acryl resin, followed by sectioning buccolingually. Dye penetration was observed under a stereomicroscope and scored. Data were statistically analyzed with Kruskal-Wallis and Mann-Whitney U tests. P<0.05 was set as the level of significance.Results. Only in the Excite group, contamination did not have adverse effects on dentin microleakage (P > 0.05). In the contaminated groups, Excite had significantly less microleakage than the others (P = 0.003). AdheSE and AdheSE One did not exhibit significant difference in microleakage (P > 0.05).Conclusion. ViscoStat hemostatic agent increased dentinal microleakage in AdheSE and AdheSE One adhesives with no effect on Excite.

Microleakage of Different Self-Adhesive Materials for Lithium Disilicate CAD/CAM Crowns

Objectives: To evaluate the microleakage and marginal gap of various luting materials after cementing ceramic crowns. Methods: Cervical margins of human molars were designed as circular chamfers. Cementation of full-contour ceramic crowns was conducted with zinc-phosphate cement (Harvard cement), resin cement (Panavia F 2.0) and self-adhesive resin cements (RelyX Unicem, BifixSE, MaxCem Elite, PermaCem2.0, G-Cem). Aging of specimens was performed in artificial saliva, at 37 °C for four weeks and thermocycling. The marginal gap was measured with a scanning electron microscope and silver precipitation within the microleakage. All data were compared statistically. Results: Independent of the margin preparation, the highest median value for microleakage was 320.2 μm (Harvard cement), and the lowest was 0 μm (Panavia F 2.0). The median value for enamel was 0 µm and for dentin 270.9 μm (p < 0.001), which was independent of the luting material. The marginal and absolute marginal gaps were not significantly different between the tested materials. There was no correlation between microleakage and the marginal gaps. Conclusion: Significant differences in microleakage were found between the tested luting materials (p < 0.05). Independent from the luting materials, the microleakage in dentin showed significantly higher values than in enamel.

Marginal Leakage of Class V Composite Restorations Assessed Using Microcomputed Tomography and Scanning Electron Microscope

The aim of the study was to compare in Class V composite restorations marginal leakage measurements obtained with microcomputed tomography (micro-CT) and scanning electron microscopy (SEM) observations. Class V cavities were prepared on 10 human molars and restored using Optibond FL (Kerr, Orange, CA, USA) and Premise Flowable (Kerr). Sealing ability was evaluated by assessing silver-nitrate penetration depth along enamel and dentin margins. Leakage was quantified using a scoring system. Micro-CT analysis provided 502 cross-sectional images for each tooth. Microleakage evaluation was performed first on three cross-sections corresponding to the sections examined by SEM, then on all 502 of the obtained micro-CT images. SEM observations were performed first at 20× magnification, then, if showing a zero score, at 80× magnification. Enamel and dentin microleakage scores assigned to corresponding sections through micro-CT and SEM (20×) were compared (Wilcoxon signed-rank test, α=0.05). No statistically significant difference in leakage scores emerged between micro-CT and 20×-magnification SEM. Eight tooth sections that were given a zero score under SEM at 20× magnification showed to be infiltrated at the higher magnification (80×). For five teeth a higher score was assigned following scanning of 502 cross-sections than based on the observation of three sections. Micro-CT presents as a valid, nondestructive in vitro method to quantitatively evaluate marginal leakage of adhesive restorations.

The importance of dentin collagen fibrils on the marginal sealing of adhesive restorations: An in vitro study

Aim: This study is aimed to evaluate the importance of collagen fi brils in the adhesion of diff erent self-etching adhesive materials to dentin. Methods: Sixty Class V restorations were prepared on the buccal and lingual surfaces of 30 recently extracted human premolars, with the cervical margins in dentin and the occlusal margins in enamel. These restorations were distributed to three groups of 20 cavities each based on the employed adhesive system used: Group A: G-Bond (GC, Corporation Tokyo, Japan); Group B: Xeno V (Dentsply Caulk Milford, DE, USA); Group C: Adper Easy One (3M/ESPE). Each group was subdivided according to dentin treatment: Subgroup 1 - manufacturer’s adhesive protocol and Subgroup 2 - Removal of the collagens fi bers (total etch + sodium hypochlorite 5% for 2 min) + adhesive protocol. After the restorations, the teeth were subjected to thermal cycling, washing and scoring according to dye penetration. Dye penetration was evaluated using steriomicroscope. Results: When the dentin microleakage scores were compared in subgroups A1VsA2, B1VsB2 and C1VsC2, then Mann–Whitney test revealed signifi cant diff erences between Subgroup A1 and Subgroup A2 (P < 5%). There was no signifi cant diff erence in Groups B and C. Conclusion: The results revealed that the collagen fi brils are not required for adhesion, and their removal improves the marginal seal of G-Bond, an acetone based dentin bonding system.

KTP Laser on Microleakage of Compomer Restorations in Class V Restorations

To evaluate the effects of pulsed KTP (potassium-titanyl-phosphate) laser on decrease of dentinal microleakage of compomer restorations in primary teeth. Twenty four primary molars were selected for the study After Class V cavity preparations in buccal and lingual surfaces, teeth were divided into three groups: Group 1: Control, Group 2: 1 WKTP laser Group 3: 1.5 WKTP laser. Then cavities were restored with compomer and teeth were thermocycled to 500 cycles, isolated and immersed in 0.5% basic fuchsin for 24 hours. Teeth were rinsed, dried, and sectioned, and microleakage was assessed by dye penetration at the occlusal and gingival surface of the teeth with stereomicroscope (40X). The data were analyzed with Kruskal-Wallis, Mann-Whitney U and Wilcoxon tests. When the scores of microleakage at the gingival margins of the groups were compared, the differences among the groups were found to be statistically significant (p<0.05). At the occlusal margins of the groups, there were no statistical differences (p>0.05). Comparing the gingival and the occlusal margins in the each group, statistically significant differences existed in the Groups 1 and 3 (p<0.05). KTP laser is able to seal dentinal tubules and consequently reduce microleakage towards pulp in primary teeth.

Marginal Sealing Durability of Two Contemporary Self-Etch Adhesives

Introduction. Sealing abilities of two self-etch adhesives were evaluated after two aging processes: storage in water and thermocycling. Materials and Methods. Cl V cavities were prepared on the buccal and lingual aspects of 48 human premolars, with cervical margins 1 mm below the CEJ. Clearfil Protect Bond (CPB) and BeautiBond (BB) (two-step and one-step self-etch adhesives, resp.) were applied, each to half of the cavities and restored with composite resin. Each group was randomly subdivided into 4 subgroups (n = 12) and evaluated for dye penetration after 24 hours, after 3000 thermocycling rounds, after a 6-month water storage, and after 3000 thermocycling rounds plus 6-month water storage, respectively. Data was analyzed using SPSS 11.5 and Kruskal-Wallis and Mann-Whitney U tests (α = 0.05). Results. There were no significant differences in enamel and dentin microleakage between the adhesives (P = 0.683; P = 0.154). Furthermore, no significant differences were observed in enamel microleakage of each one of CPB and BB (P = 0.061 and P = 0.318, resp.). However, significant decrease was observed in subgroups 3 and 4 (P = 0.001) for CPB dentinal margins. Conclusion. In this study, limited aging procedures had no influence on marginal integrity of composite resin restorations bonded with self-etch adhesives of CPB and BB. Furthermore, CPB dentinal sealing improved after aging.