Significant Difference In Microleakage Research Articles

Microleakage of luting cements in CAD/CAM pediatric zirconia crowns: an in vitro study

The durability of pediatric zirconia crowns for primary teeth is influenced by the choice of luting cement, with the effectiveness of the cement being directly correlated to its ability to reduce microleakage. This in vitro study aimed to assess and compare the microleakage of custom-made zirconia crowns (CZCs) and prefabricated zirconia crowns (PZCs) on primary maxillary incisors when luted with self-adhesive resin cement, resin-modified glass ionomer cement (RMGIC), and bioactive cement. Sixty primary maxillary incisors were prepared and allocated into two groups, each corresponding to the two types of crowns. These groups were further divided into three subgroups each to test the different luting cements. Following the cementation process and thermocycling, the specimens were immersed in a 2% methylene blue solution for microleakage evaluation. The analysis involved sectioning the teeth and examining them under a stereomicroscope. Statistical analysis, using two-way ANOVA and post hoc Dunnett T3 tests (p < 0.05), revealed significant differences in microleakage among the cements. The study found that PZCs luted with RMGIC showed the highest level of microleakage, whereas those luted with bioactive cement exhibited the lowest, positioning bioactive cement as the preferable choice for minimizing microleakage. This finding illustrates the critical importance of selecting appropriate luting cements to optimize the clinical outcomes of zirconia crown restorations in pediatric dentistry, focusing on reducing microleakage to ensure the restoration’s durability and success.

Microleakage of Class II Posterior Composite Restorations with and Without use of Liners - A Comparative Study.

This study aims to compare the effect of liner on microleakage in Class II restorations at the occlusal and gingival levels when restored with a nanocomposite. A total of 60 mandibular molars were selected and divided into three groups. Cavities in Group A were restored with posterior nanocomposite without liner, samples of Group B were restored with posterior nanocomposite with flowable composite liner and in Group C samples were restored with posterior nanocomposite with resin-modified glass ionomer cement (RMGIC) liner. Samples were stored at 37°C in 100% humidity for 14 days. Samples were subsequently immersed in 0.5% methylene blue dye and then placed under water for 15 mins. Teeth were sectioned mesiodistally with a diamond disc and examined under a stereomicroscope. All the cavities exhibited dye penetration along the occlusal and gingival margins of the restored cavities. Group A showed maximum leakage compared to Groups B and C, which was statistically significant ( P = 0.001 and P < 0.0001). No significant difference in microleakage was observed between Groups B and C. Microleakage was more in gingival margins as compared to occlusal margins in all the groups. Based on the results of the present study, it may be concluded that the placement of liner beneath nanocomposite restoration results in a significant reduction in microleakage.

Evaluation of the ceramic laminate veneer-tooth interface after different resin cement excess removal techniques.

To compare, in vitro, resin cement excess removal techniques at the veneer-tooth interface. Anterior human teeth were restored with ceramic veneers and randomly divided according to the following techniques (n = 10): removal of excess resin cement with brush and dental floss, followed by light-curing with Valo (Group 1) or Elipar (Group 2) for 1min and 40s; tack-curing with Valo (Group 3) or Elipar (Group 4) for 1s; and tack-curing with Valo (Group 5) or Elipar (Group 6) for 5s. The tack-curing was followed by removal of excess with probe and dental floss and light-curing for 1min and 40s. The area of excess resin cement (mm2) was measured in micro-CT images using AutoCAD program. The failures at the cervical margin in the X, Y, and Z axes (µm) of greater value were measured using the DataViewer program. The specimens were submitted to microleakage with 2% basic fuchsin. According to the Kruskal-Wallis and multiple comparison test, the highest area of excess resin cement was found in Group 1 (5.06 mm2), which did not differ statistically from Groups 2 (3.70 mm2) and 5 (2.19 mm2). Groups 2, 3 (1.73 mm2), 4 (1.14 mm2), and 5 (2.18 mm2) did not differ statistically. Group 6 (0.77 mm2) obtained the lowest value, which did not differ statistically from Groups 3 and 4. According to the Kruskal-Wallis and Dunn test, there was no significant difference in failures in X (p = 0.981), Y (p = 0.860), and Z (p = 0.638) axes and no significant difference in microleakage (p = 0.203) among the groups. Tack-curing for 1s or 5s, followed by removal of excess resin cement using a probe and a dental floss, tended to result in a lower amount of excess material around the margin. The technique used for resin cement excess removal influences the amount of excess leaved at the veneer-tooth interface. Tack-curing for 1s or 5s is recommended to mitigate the excess resin cement.

Evaluation of Marginal Adaptation of Metal Ceramic Crown with Different Luting Cement

The study aims to evaluate and compare the microleakage of three different luting materials. The materials compared are Zinc phosphate cement, Variolink II Refill and Glass ionomer resin cement. Eighteen recently extracted caries-free wisdom teeth were used . The teeth were cleaned then stored in distilled water until use. The molars were assigned randomly into three groups of 6 teeth of each . The metal ceramic crowns were constructed by means of an indirect laboratory technique. In group A, the crowns were cemented with a traditional Zinc Phosphate. In group B, the tooth preparations were sealed with Variolink II Refill. In group C, the tooth preparations were sealed with glass ionomer resin cement prior to cementation with the crowns. The results showed higher value of microleakage for Zinc phosphate cement. While the least value was for the Variolink II . The value for Glass ionomer resin cement was low. Statistically analysis revealed difference between the Zinc phosphate cement ,Variolink II and Glass ionomer resin cement in microleakage. There was no significant difference in microleakage between Variolink II and Glass ionomer resin cement. This may indicated that the degree of microleakage may influenced by the type of the luting system used.

Evaluation of Sealing Ability of New Composite Filling Material

This study was conducted to investigate the sealing ability (microleakage) of new composite restorative materials at tooth/composite interface.Thirty non carious, extracted human premolars teeth were mounted in acrylic resin, the teeth were randomly divided into three groups (n=10) according to the type of composite (tetric T-Econom, Evo ceram,IPS Empress). A standardize class V (5×3×2) mm dimensions cavity was prepared on the facial surface of each tooth (each group with corresponding bur type). After the specimens were filled with three types of composite restoration. They stored for one month in 37ºc distilled water, thermo cycled for 500 cycles between (5ºc &amp; 55ºc) and immersed in 2% methylene blue solution for 24h., and then sectioned longitudinally. For both occlusal and gingival margins, dye penetration at the tooth/composite interfaces were scored from 0-3 under stereomicroscope at a magnification x10. Data were analyzed using unpaired T-test, ANOVA, and Duncan’s multiple rang test at 5% significant level.Kruskal-wallis test show that there was a significant difference in microleakage between the three types of composite it represent that there was less microleakage in group filled with IPS Empress while tetric T-Econom show the highest leakage.There was no significant difference in microleakage between IPS Empress and Evo ceram composite filling.AS Conclusions; Within the limitations of this in vitro study the results show that there was less microleakage in the cavities filled with IPS Empress composite and EVO ceram composite as compared with Tetric T-Econom composite.

Evaluation of Microleakage of Orthograde Root-Filling Materials in Immature Permanent Teeth: An In Vitro Study.

Introduction: The absence of a barrier in an open root apex makes endodontic treatment challenging as root-filling material can easily reach the surrounding tissue. The aim of the study was to compare the apical microleakage associated with mineral trioxide aggregate (MTA), biodentine, custom-made gutta-percha with MTA plus and custom-made gutta-percha with Adseal in immature permanent teeth by dye penetration method. Methods: Apical 2 mm of 60 single-rooted mandibular premolar teeth was resected to create divergent open apices and 10 teeth each were filled with Biodentine plug, MTA plug, custom-made gutta-percha with MTA plus sealer and custom-made gutta-percha with Adseal sealer. Ten teeth each acted as positive and negative controls. All the samples were stored at 37°C at 100% humidity for 5 weeks and then immersed in 2% Rhodamine B dye for 24 h. Transverse sectioning was done apically at 1 mm and 3 mm to evaluate dye penetration under a fluorescence microscope using ImageJ software. Results: There was a significantly greater microleakage at 1 mm cross section compared to 3 mm (p < 0.0001). At 1 mm cross section, the apical microleakage was the highest for the MTA plug with a mean leakage percentage of 48.08 ± 16.38, a mean depth of leakage of 0.46 ± 0.10 mm and a mean area of leakage of 1.35 ± 0.74 mm2, compared to other groups, and the difference was statistically significant. However, at a 3 mm cross section, MTA plus sealer with gutta-percha demonstrated the highest mean leakage percentage (25.01 ± 7.77) compared to other groups and the difference was statistically significant (p = 0.03). Conclusion: It can be concluded that the 3-mm-thick apical plug provided better sealing of the open apex compared to the 1 mm apical plug and there was no significant difference in microleakage among the Biodentine plug, MTA plug and Adseal sealer with gutta-percha plug at 3 mm cross section.

The effect of silver diamine fluoride on the microleakage of glass ionomer restoration in primary teeth at different time intervals

Silver diamine fluoride (SDF) has shown effectiveness in hardening tooth structure and killing bacteria. Therefore, it can be used to prevent and arrest dental caries. Riva Star (SDF) treatment alone will stop cavities but will not reverse the cavitation. The Silver Modified Atraumatic Procedure, often known as Smart, is the optimum technique for regaining the tooth's structure and function. Glass ionomer was introduced in (1972) as a new material that has become one of the most widely used materials in restorative dentistry. By releasing fluoride ions, this material has a therapeutic impact on the surrounding tooth structure. Microleakage is the ingress of bacteria, its byproducts, toxins, chemicals, oral fluids, and ions between the margins of the restoration and the cavity walls. Dental restoration lifetime is significantly influenced by microleakage at the toothrestoration contact. Material and method: In this study, we used 32 primary molars, class V cavities prepared on the buccal surface of all teeth. The teeth were divided into 2 groups: Group 1: 16 teeth treated with 38%SDF 8 of them restored directly with GIC filling and the other 8 restored after 14 days; Group 2: 16 teeth as control group left untreated with 38% SDF,8 teeth restored directly and 8 restored after 14 days. Samples were thermocycled, immersed in 2% methylene blue and then sectioned in a buccolingual direction. Dye penetration was measured with a digital camera connected to a stereo microscope. Result: results of this study showed a significant difference in microleakage between two-time intervals in which microleakage in GIC filling decreased at 14-day intervals than that of first-day interval in the experimental group, while in the control group, microleakage at 14 days intervals was higher than first-day interval, but it was not significant. Conclusion: Pretreatment of the primary teeth with SDF can decrease the microleakage of GIC restoration. If placed after 14 days, the microleakage would be lesser than that if the restoration was placed directly after SDF treatment. Therefore, it is recommended that SDF treatment be done, followed by a permanent restoration after 14 days, so the null hypothesis cannot be accepted. Keywords: Microleakage, Silver diamine fluoride, Glass ionomer filling, noninvasive dentistry

In vitro microleakage at the enamel and dentin margins of class II cavities of primary molars restored with a bulk-fill and a conventional composite.

This study assessed the enamel and dentin margin microleakage of class II cavities of primary molars restored with a bulk-fill and a conventional composite. In this in vitro, experimental study, standard class II cavities were created in the proximal surfaces of 60 extracted primary molars. The teeth were randomly divided into two groups, and restored with SonicFill bulk-fill and Filtek Z250 conventional composite along with Single Bond 2 adhesive. The teeth were coated with two layers of nail varnish to 1 mm around the restoration margins, and the apices were sealed with wax. The teeth underwent 1500 thermal cycles and incubated at 37°C for 24 h. They were then immersed in 1 M silver nitrate in the dark, rinsed with water, immersed in developing solution for 12 h, and exposed to fluorescent light. Next, they were mesiodistally sectioned, and digitally photographed under a stereomicroscope at ×10 magnification. The dye penetration depth was measured by a blind observer, and analyzed by the Mann-Whitney U test (α = .05). No significant difference existed in microleakage between the two composite groups at the enamel (p = .76) or dentin (p = .16) margins. In both composite groups, microleakage at the dentin margins was significantly greater than that at the enamel margins (p = .000). Considering the absence of a significant difference in microleakage, SonicFill bulk-fill composite can be used as an alternative to Filtek Z250 conventional composite for restoration of primary molars to benefit from its advantages such as simpler and faster application.

Stamp Technique: An Explorative SEM Analysis.

Achieving correct tooth anatomy and saving time at the dental chair are some of the goals of modern restorative dentistry. Stamp technique has gained acceptance in clinical practice. The aim of this study was to evaluate the effectiveness of this technique in terms of microleakage, voids, overhangs and marginal adaptation of Class I restorations, and to analyse the operative times in comparison with traditional restorative procedures. Twenty extracted teeth were divided into 2 groups. Ten teeth in the study group (SG) were Class I prepared and restored using stamp technique, and ten teeth in the control group (CG) were Class I restored traditionally. SEM analysis was performed to evaluate voids, microleakage, overhangs, and marginal adaptation, and operative times were recorded. A statistical analysis was performed. There were no significant differences in microleakage, marginal adaptation and filling defects between the two groups, however, the stamp technique seems to facilitate the formation of large overflowing margins that require a careful finishing phase. Stamp technique does not seem to have any critical aspects in terms of restoration durability and it can be performed in a short time.

Microleakage of Class II Bulk-Fill Resin Composite Restorations Cured with Light-Emitting Diode versus Quartz Tungsten-Halogen Light: An In Vitro Study in Human Teeth

Background: Resin composites undergo a certain degree of shrinkage when light-cured with different light sources available on the market, resulting in microleakage of dental restorations. The aim of the present study was to assess microleakage of class II restorations with bulk-fill resin composites cured with LED (light-emitting diode) and QTH (quartz tungsten-halogen light) units, both in cervical and occlusal areas of cavity preparations. Materials and Methods: In the present in vitro experimental study, a total of 30 human molar teeth were used, in which 60 class II cavities were prepared (mesial and distal) and restored with Filtek bulk fill resin composite. Restorations were equally distributed in 3 groups according to type of curing light: A, QTH (Litex 680A Dentamerica®); B, LED (Bluephase N® 3rd generation); and C, LED (Valo® 3rd generation). Each group was further subdivided into subgroups 1 and 2 according to IV-A or IV-B resin composite color. Restored teeth were subjected to 20,000 thermal cycles between 5° and 55 °C, then immersed in 1M silver nitrate solution for 24 h. Subsequently, the teeth were sectioned mesiodistally to obtain samples for observation under stereomicroscope in order to determine microleakage degree. Kruskal-Wallis H and Mann-Whitney U statistical tests were applied with a significance level of 5% (p < 0.05). Results: No statistically significant differences were found in the degree of microleakage of bulk-fill resin composites light-cured with LED and QTH units for both occlusal (p > 0.05) and cervical areas (p > 0.05). Additionally, no significant differences were found when comparing microleakage between occlusal and cervical areas (p > 0.05), regardless of lamp type. In addition, significant differences in microleakage degree were found between bulk-fill resins with IV-A and IV-B shades when they were light-cured with QTH at cervical level (p = 0.023). However, there were no significant differences when comparing these bulk-fill resin composite shades at occlusal level with LED (p > 0.05) and QTH (p > 0.05) units. Conclusions: Class II restorations with bulk-fill resin composite in IV-A and IV-B shades light-cured with third generation LED lamp and QTH showed no significant differences in microleakage when compared in both occlusal and cervical areas. On the other hand, significantly more microleakage was found at the cervical level when a darker shade of resin composite was used and light-cured with the QTH unit.

Microleakage in indirect onlay restorations cemented with three different types of adhesives: An in vitro study.

To evaluate the in vitro degree of marginal microleakage in indirect Class II onlay restorations cemented with dual self-adhesive, universal adhesive and dual adhesive. In the present in vitro experimental study, a total of 54 human premolar teeth were prepared and divided into three equal groups (n = 18) for placement of onlay-type restorations cemented with A: Allcem™ dual-cure adhesive cement), B: RelyX™U200 dual-cure self-adhesive cement and C: RelyX™ Ultimate universal adhesive cement. All restorations were subjected to 10,000 thermocycles between 5°C and 55°C and immersed in a 1M silver nitrate solution for 6 hours. The crowns were then sectioned mesiodistally and observed under a stereo microscope to determine the degree of marginal microleakage in the cervical area. The onlay restorations cemented with RelyX Ultimate did not present microleakage in the majority of cases (77.8%). Restorations cemented with RelyX U200 showed predominantly microleakage up to the pulp floor in 83.3% of the total, being this significantly higher microleakage than in restorations cemented with RelyX Ultimate and Allcem Dual (p<0.001 and p<0.001 respectively). There was no significant difference in microleakage between the last two mentioned cements (p=0.255). Allcem dual adhesive cement and RelyX Ultimate universal adhesive showed significantly less microleakage than RelyX U200 dual-curing self-adhesive cement at the cervical level, with predominantly no microleakage and microleakage down to the enamel, respectively. The use of RelyX Ultimate cement in indirect restorations is recommended as it showed better marginal adaptation. Key words:Microleakage, human teeth, adhesion, adhesive cement, thermal cycling, onlay restoration.

Dentin drying methods affect the apical seal of three root canal sealers

Aim of the study: The purpose of this research was to see how drying protocols affected the apical sealing of teeth filled with various sealers.&#x0D; Materials and methods: Protaper rotary files were used for root canals instrumentation of ninety teeth with single root canal. According to the drying protocol, the teeth were separated into three groups (n = 30): "GI–paper points"; "GII–ethanol + paper points"; "GIII–EndoVac + paper points". Using a single-cone approach, every group was separated to three subgroups based on the sealer used: BiooRoot sealer, Epoxy resin and zinc oxide eugenol (ZOE), The apical dye penetration in millimeter was examined under a streromicroscope to assess apical seal. The data was submitted to one –way ANOVA and T test.&#x0D; Results: The result showed statistically no significant difference in microleakage between bioRoot and Epoxy resin (p &gt; 0.05) while there was significant differences of microleakage between ZOE and other sealers, and there is no significant difference between drying protocols in canals obturated with each used sealers (BioRoot, Epoxy resin and ZOE).&#x0D; Conclusion: Drying protocols have no effect on the apical seal of the tested sealers.

Effects of the conventional, soft start, and pulse delay modes produced by light-emitting diode device on microleakage beneath metal brackets: An in vitro comparative study

This study aimed to evaluate microleakage beneath metal brackets cured by different light curing modes. Sixty extracted human premolars were randomly divided into three groups according to the light curing mode. Metal brackets were bonded in all groups according to the manufacturer's recommendations with a light-emitting diode device. Light curing was applied as follows: group 1: conventional mode (10s mesial+10s distal); group 2: soft start mode (15s mesial+15s distal); group 3: pulse delay mode (3s mesial+3s distal, followed by 3min of no photoactivation, then 9s mesial+9s distal). Radiant exposure was the same in all study groups. After curing, the teeth were incubated at 37 degrees for 24hours, then thermocycled 500 times. Next, they were sealed with nail varnish, immersed in methylene blue 1% for 24hours, sectioned, and examined under a stereomicroscope. Microleakage was measured at both enamel-adhesive and bracket-adhesive interfaces, and the total microleakage for each tooth was computed. Statistical analyses were performed using Kruskal-Wallis and Welch test for comparing microleakage among groups. Wilcoxon signed ranks test was used for comparing microleakage between the bracket-adhesive and enamel-adhesive interfaces. There was no significant difference in microleakage at the bracket-adhesive interface among study groups. At the enamel-adhesive interface and total microleakage, the pulse delay group exhibited significantly lower microleakage than the conventional group. Whereas there was no significant difference between the soft start group and other study groups. In all study groups, microleakage at the enamel-adhesive interface was greater than that at the bracket-adhesive interface. The pulse delay mode caused lesser microleakage than the conventional mode. This supports the use of this mode in orthodontic bonding.

The Difference of Microleakage Between One-Bulkfill Resin Composite and Conventional Resin Composite

Resin composites are the most commonly used restorative materials and are constantly evolving due to their shortcomings which can affect the restoration results in polymerization shrinkage, leading to the formation of microleakage. Although incremental techniques have been found, this technique has drawbacks regarding the time required and the possibility of contamination. The invention of bulk fill resin composite can solve this problem. Manufacturers of One-Bulkfill (3M ESPE) claim that this material has less polymerization shrinkage than conventional resin composites, which is expected to have less chance of microleakage. This study aims to determine the difference in microleakage between one-bulkfill resin composites and conventional resin composites. 20 extracted premolars without caries and anomalies were utilized as research samples. These teeth were then prepared to form a class 1 cavity, then divided into two groups, namely; (1) One-Bulkfill (3M ESPE) and (2) Z350 XT (3M ESPE). These two samples were immersed in 1% Methylene Blue solution and observed using a Camera with a Macro Lens. Data were analyzed using an independent sample t-test. The results demonstrated a significant difference in microleakage between the two groups (p = 0.014, p0.05). The mean value of microleakage in One-Bukfill composite resin restorations was 0.022, while Z350 XT composite resin restorations had 0.038. It can be concluded that the One-Bulkfill composite resin restoration had a smaller microleakage value than the conventional composite resin restoration (Z350 XT).

Evaluation of microleakage and push-out bond strength of various composite resins for sealing the screw-access channel in implant-supported restorations

Statement of problemMicroleakage and loss of the composite resin sealing the screw-access channel are frequent complications of screw-retained implant-supported prostheses. How the screw-access channel should be best restored to reduce such complications is unclear. PurposeThe purpose of this in vitro study was to evaluate the microleakage and bond strength of 3 types of composite resins (flowable, packable, and bulk-fill) with or without a bonding agent treatment to seal the screw-access channel of 2 types of restorative materials (zirconia and Co-Cr alloy) with or without thermocycling. Material and methodsIn total, 240 yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) specimens (IPS e.max ZirCAD) and 240 Co-Cr alloy (Vera PDS) specimens were prepared with a Ø3×3-mm cylindrical cavity at the center to simulate the screw-access channel. Three types of composite resins (flowable, packable, and bulk-fill resin) (Filtek Z350 XT Flowable Restorative, Filtek Z350 XT Universal Restorative, and Filtek One Bulk Fill Restorative) were applied to restore the access channel of the zirconia and Co-Cr specimens with or without a bonding agent (Single Bond Universal Adhesive). Microleakage and push-out bond strength were determined and compared by dividing the specimens into experimental groups with or without thermocycling (1000 times with 30 seconds at 5 ±2 °C and 55 ±2 °C). The results were analyzed by using a 1-way ANOVA and 4-way ANOVA. Adjustment for multiple comparisons was made with the Tukey Honestly Significant Difference (HSD) test. ResultsThe specimens subjected to thermocycling showed a lower bond strength (P<.001) and higher microleakage (P<.001) than specimens stored in a constant-temperature water bath. Specimens treated with bonding agents showed a higher bond strength (P<.001) and lower microleakage (P<.001) than specimens not treated with a bonding agent. Higher bond strengths were observed in the order of bulk-fill resin, packable resin, and flowable resin (P<.001). Packable resin showed higher microleakage than flowable resin and bulk-fill resin (P<.05). No significant difference in microleakage was found between the flowable resin and bulk-fill resin (P>.05). ConclusionsHigher bond strengths were observed in the order of bulk-fill resin, packable resin, and flowable resin. Less microleakage was observed in the flowable resin and bulk-fill resin than in the packable composite resin. Bonding agent treatment was effective in increasing bond strength and decreasing microleakage. Zirconia and Co-Cr showed a bond strength similar to that of composite resins, but zirconia showed higher microleakage than Co-Cr. Restoring the screw-access channel with the bulk-fill resin should increase bond strength and reduce microleakage.

Comparación de la adaptación marginal y microfiltración entre dos sistemas de zirconia, con un mismo medio cementante

Objetivo: Comparar la adaptación marginal y microfiltración de las cofías Lava™ y Zirkon zahn® con un mismo medio cementante. Materiales y Métodos: Veinte premolares superiores extraídos fueron divididos en dos grupos. Un grupo fue preparado para recibir cofías de Lava™ y el otro para Zirkon zahn®. Las cofías fueron elaboradas siguiendo los estándares de cada sistema. Fue medida la adaptación marginal en micras en ocho zonas antes y después de ser cementadas con RelyX™ U100. Después de termocicladas las muestras fueron embebidas en fushina al 2% y seccionadas bucopalatino, para medir la microfiltración en micras en cada sección tanto en vestibular como en palatino. Resultados: Existió una diferencia estadística significativa en la adaptación marginal entre los dos sistemas de zirconia. El sistema que reportó mejor adaptación fue Lava™ con valores de 19.7µm antes de cementar y 15.0µm después de cementar, el sistema con menor adaptación marginal fue Zirkon zahn® con valores de 28.1µm antes de cementar y 22.8µm después de cementar. No hubo una diferencia significativa en la microfiltración, el promedio para Lava™ fue de 314.2µm y de Zirkon zahn® de 319.8µm. Conclusión: El sistema que reportó mejor ajuste marginal, con una diferencia estadística significativa, fue Lava™, por lo que el sistema con menor ajuste marginal fue Zirkon zahn®, sin embargo no hubo diferencia significativa en la microfiltración entre estos sistemas.

Effect of a fiber-reinforcing technique for direct composite restorations of structurally compromised teeth on marginal microleakage.

To evaluate if the marginal microleakage of extensive Class I composite resin restorations can be affected by applying ultra-high-molecular-weight polyethylene (UHMWPE) fibers with the wallpapering technique combined with different restorative materials and methods. A 120 human molars were selected and one extensive Class I cavity was prepared on the occlusal surface of each tooth. The specimens were divided into 12 groups (n=10) according to the type of restorative material (Filtek Z550, Beautifil II LS or Beautifil Bulk Restorative), the use or not of reinforcing fibers (ribbond) and the applied restorative technique (incremental or bulk). The specimens were subjected to thermocycling and then immersed into a 50 wt% silver nitrate solution following a dying protocol. Subsequently, the teeth were prepared for SEM observations to evaluate the extent of marginal microleakage. Three-way ANOVA revealed that the type of material, the use of ribbond fibers and the type of restorative technique significantly affected marginal microleakage (p < 0.001). Application of ribbond fibers decreased marginal microleakage to all tested restorative materials, regardless of the restorative technique, in a range of 31.2-81.4%. In the groups with no-use of ribbond fibers, among the materials there were no significant differences in microleakage when the teeth were restored with the incremental technique (p > 0.05). The use of UHMWPE fibers with wallpapering technique in Class I composite restorations may be an effective method to reduce marginal microleakage, regardless of the selected restorative technique or the material. Clinicians may be encouraged to utilize reinforcing fiber restorative techniques for direct restorations of structurally compromised teeth as a valid alternative to indirect restorations.

Effects of Rinsing Water Temperature and Preheated Composites on Microleakage of Composite Restorations with Two Bonding Agents.

Objectives: The aim of this study was to evaluate the effects of rinsing water temperature and preheated composites on microleakage of class V restorations with two different bonding agents. Materials and Methods: Eighty class V cavities were prepared in the buccal and lingual surfaces of 40 molars. Single Bond and Prime and Bond NT bonding agents were used. The teeth were divided into four groups of 10. G1: After acid etching, cavities were rinsed with 23˚C water and filled with 23˚C composite resin. G2: Rinsing water and composite resin had 55˚C temperature. G3: Rinsing water had 55˚C and composite resin had 23˚C temperature. G4: Rinsing water had 23˚C and composite resin had 55˚C temperature. The specimens were immersed in 0.5% basic fuchsine dye. Microleakage scores were analysed with the Kruskal-Wallis, Mann-Whitney U, and Wilcoxon tests. Results: There were significant differences in microleakage of specimens prepared with Single Bond and Prime and Bond NT only in group 1 (P<0.05). There were no significant differences between the microleakage of groups rinsed with different water temperatures (P>0.05). There were significant differences between the unheated and preheated composite groups (P<0.05). Conclusion: Preheating of composite is a valuable method to increase its adaptability and decrease microleakage of composite restorations.

Evaluation of Microleakage in Resin Composites Bonded to an Er:YAG Laser and Bur-Prepared Root and Coronal Dentin Using Different Bonding Agents.

Introduction: This study was conducted to assess the microleakage in Er:YAG laser-ablated and bur-prepared root and coronal dentin cavities using self-etch and total-etch adhesive systems. Methods: Sixty extracted caries-free human third molars were sectioned for dentin exposure. Then, two standard class V cavities were prepared in the root and coronal dentin of each tooth and allocated to one of the following conditioning groups randomly (n=12/Group): G1: Diamond bur for cavity preparation and single bond (BESB) etch-and-rinse adhesive for bonding, G2: Er:YAG laser (160 mJ, 20 Hz, 29.88 J/cm2) and SB (LESB), G3: Er:YAG laser and SB without acid etching (LSB), G4: Diamond bur and Clearfil SE Bond (BCSE) self-etch system, and G5: Er:YAG laser and Clearfil SE Bond (LCSE). The cavities were filled with Z100 composite resin. Dye penetration was assessed after thermocycling. Data analysis was done by Kruskal-Wallis and Mann-Whitney U tests. Statistical significance was set at P<0.05. Results: The results showed there were no statistically significant differences in microleakage between the two preparation methods (bur and laser) or the bonding agents applied (P>0.05). Regardless of the cavity preparation method, dye penetration was significantly higher in coronal dentin than in root dentin (P<0.05). Conclusion: The Er:YAG laser had the same efficacy as the conventional method for cavity preparation, and microleakage did not depend on the bonding agent. Microleakage was significantly higher in coronal restorations than in root restorations.

WITHDRAWN: Impact of riboflavin and curcumin mediated photodynamic therapy and Er,Cr:YSGG on microleakage of class V resin glass ionomer restorations in permanent molar teeth

The present study aimed to evaluate the impact of PDT using curcumin and riboflavin as photosensitizers and Er,Cr:YSGG on microleakage in class V RMGIC restorations in permanent teeth. Eighty permanent molars were investigated and randomly divided into 4 groups: control group: resin-modified glass ionomer restoration with no treatment, R-PDT: PDT with riboflavin, Cu-PDT: PDT with curcumin (Cu) and, Er,Cr:YSGG: laser application. All the teeth in each group were restored with the help of RMGIC. The samples were dipped for 24 h in 0.5 % Fuchsine solution, and subsequently fixed in acrylic resin-based molds. Microleakage scores were estimated considering both cervical and occlusal boundaries. Intergroup comparisons were made at each margin, and intragroup comparisons made at the cervical and occlusal margins. The Shapiro Wilk test was used to check the normality of the values. Whereas, the analysis of data was conducted using SPSS version 25 via the Kruskal-Wallis and Wilcoxon tests. P < 0.05 was contemplated to be statistically important. A high frequency (95%) of the enamel walls were not penetrated when subjected to treatment with R-PDT, followed by Cu-PDT and Er,Cr:YSGG. The highest amount of microleakage was observed (55%) Cu-PDT at the site of the cavity near the cementum. The least amount of microleakage was observed in the control group. A statistically significant difference in microleakage was noted at the cervical wall (p=0.015), while no significant difference was seen at the occlusal wall (p=0.789) between the groups. A significant difference was noted at the cervical wall between the control and R-PDT group (p=0.021) and Cu-PDT group (p=0.005), respectively. A significant difference in microleakage was observed when occlusal was compared with cervical walls within each group (p<0.05). Photosensitizers using riboflavin and curcumin may reduce the microleakage within the enamel surface restored with RMGIC in class V lesions that may not interfere with bonding. However, extreme caution should be taken while considering riboflavin and curcumin for class V RMGIC restorations extending to cementum surface.