Marginal Microleakage Of Class Research Articles

Influence of "soft start" polymerization on marginal sealing in resin composite restorations

The purpose of this study was to evaluate the marginal microleakage in Class II with different materials in resin composite restorations cured by using "soft start" and standard polymerization techniques. Two adhesive Class II cavities were prepared in 50 human teeth with enamel in-between. Samples were divided into 5 groups and filled with composite resins, compatible flow resin composites and bonding systems. The ocluso-mesial restorations were cured with standard curing technique, and the ocluso-distal restorations were cured with "soft start" curing technique. After thermocycling, the teeth were immersed in silver nitrate solution and sectioned for leakage evaluation. The results pointed out, after "soft start" and standard curing techniques, that the best marginal behavior in Class II restorations was obtained with Tetric Ceram / Tetric Flow composite resins, then with Filtek Z 250 / Filtek Flow, followed by Admira Admira Flow and Point / Revolution composite materials. The deepest dye penetration was found in cavities with Diamond Lite / Diamond Link composite restorations. No statistically significant difference was found in the tested composite resin restorations, whether treated with "soft start" polymerization or with standard polymerization technique, in regard to marginal micro leakage.

Influence of "soft start" polymerization on marginal sealing in resin composite restorations

The purpose of this study was to evaluate the marginal microleakage in Class II with different materials in resin composite restorations cured by using "soft start" and standard polymerization techniques. Two adhesive Class II cavities were prepared in 50 human teeth with enamel in-between. Samples were divided into 5 groups and filled with composite resins, compatible flow resin composites and bonding systems. The ocluso-mesial restorations were cured with standard curing technique, and the ocluso-distal restorations were cured with "soft start" curing technique. After thermocycling, the teeth were immersed in silver nitrate solution and sectioned for leakage evaluation. The results pointed out, after "soft start" and standard curing techniques, that the best marginal behavior in Class II restorations was obtained with Tetric Ceram / Tetric Flow composite resins, then with Filtek Z 250 / Filtek Flow, followed by Admira Admira Flow and Point / Revolution composite materials. The deepest dye penetration was found in cavities with Diamond Lite / Diamond Link composite restorations. No statistically significant difference was found in the tested composite resin restorations, whether treated with "soft start" polymerization or with standard polymerization technique, in regard to marginal micro leakage.

In vitro quantitative evaluation of marginal microleakage in Class II restorations confected with a glass ionomer cement and two composite resins.

This study evaluated, in vitro, marginal microleakage in class II restorations confected with the glass ionomer cement Vitremer and with the composite resins Ariston pHc and P-60. The aims of the study were to assess the effect of thermocycling on those materials and to evaluate two methods utilized in the analysis of dye penetration. Sixty premolars divided in three groups were utilized; the teeth had proximal cavities whose cervical walls were located 1 mm below the cementoenamel junction. Half of the test specimens from each group underwent thermocycling; the other half remained in deionized water, at 37 degrees C. The specimens were immersed, for 24 hours, in a basic 0.5% fuchsin solution at 37 degrees C. For the analysis of microleakage, the specimens were sectioned in a mesio-distal direction, and the observation was carried out with the software Imagetools. The results were evaluated through the 2-way ANOVA and through the Tukey's test. All groups presented marginal microleakage. The smallest values were obtained with Vitremer, followed by those obtained with the composite resins P-60 and Ariston pHc. There was no statistically significant difference caused by thermocycling, and the method of maximum infiltration was the best for detecting the extension of microleakage.

In vitro study of marginal microleakage in dental caries treated with Er:YAG laser and restored with esthetic materials

The aim of this in vitro study was to evaluate marginal microleakage in class V preparations submitted to treatment with Er:YAG laser and restored with aesthetic materials. Sixty human molars were selected and class V cavities were prepared on the buccal and lingual aspects of their cervical thirds. The restorative technique followed the instructions of the manufacturers. The samples were divided in 3 groups of 20 teeth each: Group 1--control; Group 2--Er:YAG laser was applied on the enamel margin before the restoration was placed; Group 3--a thin layer of calcium hydroxide was applied on the axial wall before the restoration was placed. Each group was divided in 4 sub-groups and the teeth were restored with different aesthetic materials. All samples were submitted to thermocycling and stained with 50% silver nitrate. Based on the obtained results, we could conclude that there are statistically significant differences between the 12 experimental conditions tested. The samples which presented the greatest microleakage were those treated with Er:YAG laser and restored with light-cured glass ionomer cement, followed by those that received Er:YAG laser and the sandwich technique, the cavities restored with light-cured glass ionomer cement and those restored by means of the sandwich technique, in this order.

In vitro evaluation of the marginal microleakage of class II amalgam restoration associated with dentin adhesive

The marginal microleakage of class II amalgam restorations (Dispersalloy) associated with copal varnish (Copalite) and with two dentin bonding agents (Scotchbond Multi-uso Plus and Multi Bond Alpha) was evaluated in vitro and compared by two methods: scores and linear measurements. Forty-five sound premolars were used, on which two separated class II cavities were prepared on the M and D surfaces. After the restoration, the specimens were thermocycled and stored in a solution of 0.5% basic fuchsin during 24 hours. The analysis allowed to conclude that none of the three restorative systems were able to eliminate the marginal microleakage. Nevertheless, the leakage was significantly smaller on the restorations associated with dentin bonding agents when compared to copal varnish. The linear measurement method was more sensitive than the score criteria.

In vitro evaluation of marginal microleakage of class II bonded amalgam restorations using a dentin adhesive and a glass ionomer cement

The purpose of this study was to evaluate in vitro the effectiveness of the dentin bonding system All Bond 2 associated with Resinomer (Bisco), and of Vitrebond (3M) glass ionomer cement fresh-mixed, both used in the bonded amalgam technique, to prevent short-term microleakage in class II cavities restored with Dispersalloy (Dentsply), an admixed alloy. The control group utilized the Copalite (Cooley & Cooley) varnish. Forty five sound human extracted premolars were used. Class II cavity preparations were made on the mesial and distal surfaces of non-carious teeth, with the gingival margins wall established 1mm under the cementum enamel junction. The specimens were divided randomly into three groups with thirty cavities in each group. The teeth were stored in distilled water for 24 hours and were thermocyled through 500 cycles in distilled water between 5°C and 55°C with a dwell time of 15 seconds. The apices and roots of the teeth were sealed. They were placed in a 37°C bath of 0.5% basic fuchsin dye for 24 hours. The teeth were washed in tap water for 24 hours and cut. The microleakage scores per restoration were averaged and three values of various test groups were subjected to the Kruskal-Wallis and Dunn test at a significance level of p < 0.05. The All Bond 2/Resinomer showed significantly less microleakage at gingival margins than the Vitrebond and Copalite lined to amalgam restorations. The Vitrebond fresh mixed, lined to amalgam restorations, showed significantly less microleakage than the Copalite lined to amalgam restorations.

Early marginal microleakage in class II resin composite restorations

The aim of this study was to evaluate in vitro the early marginal microleakage around conventional and sandwich Class II (MOD) restorations. Ten different combinations of dentin bonding agents, glass-ionomer cements, and posterior resin composites were used. Class II cavities were prepared in freshly extracted third molars whose root surfaces had previously been coated. All gingival margins were prepared at the cementum-enamel junction. Teeth were filled by use of a multi-incremental technique, finished with discs, and immediately immersed in 2% erythrosin B for 12 h at 37°C. Three transverse sections were made at 0.5 mm, 2 mm, and 3.5 mm over the cementum-enamel margin and evaluated under a stereomicroscope. Microleakage was scored linearly along the dentin/enamel-restoration interface. Sections at the cementum-enamel level showed significantly higher microleakage than the other two. Significant differences were observed between the various combinations of materials. Early marginal microleakage in Class II restorations depends not only on filling technique and on dentin bonding systems but also on the resin composite. Glass-ionomer cements significantly reduce early marginal microleakage in Class II restorations.