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Microleakage of indirect inlays placed on different kinds of glass ionomer cement linings.

The objective of this study is to compare the marginal seal of Class II cavities restored with indirect inlays constructed on glass ionomer cement linings having different curing properties. Also the effect of acid-etching of these liners on microleakage was investigated. Mesio-occlusal and disto-occlusal cavities in 80 extracted human molars having the cervical floor below the cementoenamel junction were prepared (n:160). Half of the preparations were restored with Ceramco II porcelain and the rest with SR-Isosit resin inlay material. Liners as light curing Ionoseal light+chemically curing LCL 8 and Zionomer and chemically curing Ketac-Bond glass ionomer cements (GICs) were used. On mesial preparations GICs were acid-etched but were not on distal preparations. All inlays were cemented with Ultrabond composite material. After thermocycling the teeth were placed in a basic fuchsin dye solution for 24 h, then each tooth was sectioned. By using a stereomicroscope the extent of marginal leakage was scored and statistically evaluated. Microleakage was observed beneath all GIC linings and was more extensive between light curing GIC/dentine interface. By acid-etching of GICs the microleakage between GIC/dentine interface was increased significantly. Whether acid-etching was applied or not a significantly increased microleakage was recorded between chemically curing GIC/composite interfaces. Although the marginal microleakage was witnessed in both inlays, it appeared that porcelain inlays provided a better marginal seal, in comparison to SR-Isosit inlays.

Acid Etching, Dental↗

The effect of pulse activation on microleakage of a 'packable' composite resin and two 'ormocers'.

The purpose of the study was to examine the effect of pulse polymerization on microleakage of one packable composite resin and two organically modified ceramics (ormocers), within a high C-factor preparation. Class-V cavity preparations with occlusal margins in enamel and gingival margins in dentin were prepared on 60 freshly extracted premolars or molars. Teeth were randomly assigned to 12 experimental groups (five teeth each) representing the different restorative systems, mode of polymerization and thermal cycling test. Three groups of 20 teeth each were restored with one of the following restorative systems: Scotch bond 1/Filtek P 60, Admira bond/Admira, Etch&Prime 3.0/Definite. 10 restorations of each restorative system (two experimental groups) were conventionally polymerized, whereas the other 10 restorations were polymerized with a pulse program. The specimens were stored in double-distilled water at 37 degrees C for 24 h. Ten restorations from each restorative system (30 restorations, half of the specimens) were thermocycled, the other 30 restorations were kept in double-distilled water at 37 degrees C for 24 h. Then all 60 restorations stained with dye, sectioned and scored for microleakage. Results showed that there were no significant differences (P > 0.05) among the materials with respect to microleakage scores. The experimental groups that were conventionally polymerized revealed significantly more microleakage (P < 0.05) after thermal cycling than all the other groups. The gingival microleakage was significantly more (P < 0.05) than occlusal in conventionally polymerized, thermocycled experimental groups.

Bicuspid↗

Evaluation of microleakage in tenure-based restorations.

This study evaluates the effects of six composite resins, which use three different curing systems, on the ability of Tenure to resist microleakage. The curing systems were a photoinitiated dual-cure system, a dual-cure system, and light-cure systems. A total of 39 human molars were used. Following 2,000 cycles on a thermocycler, specimens were exposed to 0.2 percent basic fuchsin dye for 24 hours and then examined for microleakage. Results indicated that the composite resin plays an important role in the ability of a restorative system to resist microleakage. The photoinitiated dual-cure system produced significantly less microleakage than light-activated systems. No difference in microleakage was found between light-activated systems and the dual-cure system.

Composite Resins↗

Effects of air abrasion and acid etching on the microleakage of preventive Class I resin restorations: an in vitro study.

PURPOSE: To evaluate the effects of air abrasion, acid etching, and the combination of both procedures on the microleakage of preventive Class I resin restorations. MATERIALS AND METHODS: Eighty-four extracted human molar teeth were randomly assigned to seven groups with 12 teeth each. Occlusal fissures were opened with a diamond bur and etched with phosphoric acid (groups I and VI); prepared with a diamond bur without etching (group VII); air abraded with the KCP 1000, using 50-micron aluminum oxide particles without etching (group II), and with phosphoric acid etching (group III); or air abraded with 27-micron aluminum oxide particles without etching (group IV), and with phosphoric acid etching (group V). Preparations were filled with a low-viscosity resin composite (Liquicoat, groups I to V) or with a low-viscosity polyacid-modified resin composite (PrimaFlow, groups VI and VII). Six teeth in each group were thermocycled (5 degrees-55 degrees C, 2500 cycles). Dye penetration (methylene blue) was evaluated in ordinal scale. RESULTS: The number of non-thermocycled and thermocycled specimens revealing no microleakage was as follows: group I, 6 and 1; group II, 2 and 2; group III, 4 and 3; group IV, 0 and 0; group V, 1 and 0; group VI, 3 and 2; and group VII, 0 and 0, respectively. No significant differences existed between the thermocycled specimens and non-thermocycled specimens, except within group I. CLINICAL SIGNIFICANCE: Results indicated that (1) air-abrasion treatment with 27-micron particles is less effective in preventing microleakage compared to 50-micron particles, (2) air abrasion should be combined with acid etching to reduce microleakage of preventive Class I resin restorations, and (3) acid etching significantly reduces microleakage of the low-viscosity polyacid-modified resin composite in preventive Class I restorations.

Acid Etching, Dental↗

An in vitro study of coronal microleakage in endodontically-treated teeth restored with posts.

Coronal microleakage has received considerable attention as a factor related to failure of endodontic treatment and much emphasis is placed on the quality of the final restoration. Posts are frequently used for the retention of coronal restorations. These can be custom-made or prefabricated. Many authors have examined coronal microleakage with respect to gutta-percha root fillings and plastic coronal restorations, but few have investigated the coronal seal afforded by various post systems. The seal provided by a cemented post depends on the seal of the cement used. The purpose of this study was to compare coronal microleakage around cast and prefabricated posts using a dye-penetration method. Sixty extracted single-rooted human teeth were chemomechanically prepared. The root canals were filled with gutta-percha and sealer and they were then prepared for standard posts. Six groups, each of 10 teeth, were restored with either cast post or prefrabricated post. The posts were cemented with either glass ionomer cement (GIC), Variolink II or Durelon. The teeth were thermocycled and placed in Indian ink for one week. They were then demineralised and rendered transparent. Linear coronal dye penetration around the post was measured and compared. The least dye-penetration was observed in roots restored with a cast post and Variolink II. Dentatus posts demonstrated the most microleakage. It appears that the dentine-bonding cements have less microleakage than the traditional, non-dentine-bonding cements and adaptation of the post with the canal may be more important than the cement used.

Analysis of Variance↗

Variability in microleakage observed in a total-etch wet-bonding technique under different handling conditions.

Using a stereoscopic clearing protocol and scanning electron microscopy, we investigated the extent and nature of microleakage in a total-etch, current-generation dentin adhesive by a wet-bonding technique under different handling conditions. The hypotheses were that inadequate light curing of the primer or incomplete drying of the primer solvent might adversely affect the sealing ability of an acetone-containing adhesive system. The study consisted of three experimental groups: (I) a control group with an adequate light source and with the primer solvent completely dried; (II) an "inadequate-light" group; and (III) an "incomplete evaporation of primer solvent" group. The extent of microleakage after silver staining and clearing of the specimens was scored based on a modified five-point scale. Nonparametric statistical analysis (Kruskal-Wallis ANOVA) followed by a multiple comparison test (Dunn test) indicated significant differences among the three groups (p < 0.05). SEM examination of the restorative interface revealed that microleakage appeared to be initiated from the bonding resin-hybrid layer interface in all three groups, representing the weak link in the adhesive system. In addition, microleakage was characterized by 5 zones, each delineating a stage in a continuous array of progressively deleterious microleakage patterns variously distributed among the three groups. It was suggested that, while the bonding resin-hybrid layer interface represented the intrinsic weakness in an already much improved dentin adhesive, extrinsic factors such as the adequacy of the curing light and, more importantly, complete removal of the primer solvents can and should be avoided to preserve the structural integrity of the marginal seal.

Acid Etching, Dental↗

Reduction of microleakage around new amalgam restorations.

Microleakage is a problem of all fresh amalgam restorations and is clinically undetectable. Because microleakage may be responsible for pulp irritation, pulp inflammation, necrosis, and recurrent caries, it is essential to prevent and control it. Correct cavity margin preparations, proper amalgam manipulation, proper condensation, and burnishing can minimize microleakage in amalgam restorations. The use of conventional varnish or dentin adhesive on cavity walls before the insertion of the amalgam is the best method to reduce microleakage. Most well-manipulated and well-placed amalgams do not exhibit microleakage after a time.

Bacteria↗

Depth of cure and microleakage with high-intensity and ramped resin-based composite curing lights.

BACKGROUND: The authors conducted a study to determine whether high-intensity curing lights in high and ramped intensity modes affect microleakage of resin-based composite restorations and whether different types of resin-based composites meet American National Standards Institute/American Dental Association Specification no. 27 (1993): 7.7 for depth of cure when polymerized using these lights. METHODS: The authors compared five high-intensity lights, three plasma arc lights and two quartz-tungsten-halogen lights in their regular and ramped intensity modes with a quartz-tungsten-halogen 40-second light. The parameters tested were microleakage one month after bonding and curing depth for different resin-based composite types. The authors measured curing depth using a scratch test. RESULTS: Light curing with Optilux 501 (Kerr/Demetron, Orange, Calif.) for 10 seconds and ADT Power PAC (American Dental Technologies, Corpus Christi, Texas) for 10 seconds resulted in higher microleakage values than light curing with other lights (P < .05). The microhybrid resin-based composite was the only material that met the specification when light cured with all of the lights tested. The flowable resin-based composite did not meet the specification when light cured with all lights tested. Microhybrid resin-based composite had the greatest depth of cure, and flowable resin-based composite had the least depth of cure. CONCLUSIONS: Microhybrid resin-based composite microleakage is affected by some light-curing modes. Different categories of resin-based composites are cured to different depths using high-intensity lights. CLINICAL IMPLICATIONS: Light curing with some high-intensity lights compared with halogen lights may result in higher microleakage values. Use caution when light curing flowable resin-based composite with the high-intensity lights. Place increments less than 2 millimeters in depth when using this material.

Analysis of Variance↗

Evaluation of the effect of EDTA, EGTA and CDTA on dentin adhesiveness and microleakage with different root canal sealers.

The effect of chelating solutions EDTA, EGTA and CDTA on human dentin adhesiveness and microleakage with 4 sealers (Sealer 26, Sealapex, N-Rickert and Endofill) was evaluated in vitro. Whether or not there was a mathematical correlation between the tests of adhesiveness and microleakage was also evaluated. A total of eighty maxillary and mandibular molars were used to test adhesiveness. After wearing of the occlusal surface to obtain a flat surface, the sealer was placed with an aluminum cylinder (10 mm x 6 mm). Adhesiveness was evaluated with a 4444 Instron universal testing machine. Microleakage was evaluated in 160 maxillary canines after root canal instrumentation, obturation and clearing. The penetration of India ink in the apical region was measured with a measurescope. The teeth were divided into 4 groups: group 1, distilled water, group 2, EDTA; group 3, EGTA; group 4, CDTA. Sealer 26 and EDTA had the best results (p<0.01) for adhesiveness and microleakage. There was no correlation between the test for adhesiveness and microleakage.

Adhesiveness↗

[Effect of the storage method on microleakage of primary teeth restored with different bonding systems: in vitro study].

The influence of the method of storage of teeth and the effect of two kinds of dentin-bonding agents on the microleakage at the axial and cervical walls of composite restorations, in primary second molars, were evaluated. The samples were divided in three groups: Dehydrated, Hydrated and Frozen. The Dehydrated group was kept dry, the Hydrated group was stored in physiological saline solution under refrigeration, and the Frozen group was kept in the freezer, also immersed in physiological solution. The samples received two vertical slot preparations: a mesio-occlusal and a disto-occlusal one. In the mesio-occlusal cavities, Scotchbond Multi-Use adhesive system was used, whereas in the disto-occlusal cavities Prime & Bond 2.1 system was used, and all cavities were filled with Solitaire composite resin. The groups were then thermocycled and immersed in silver nitrate solution. Microleakage was measured by means of a digitized image system and the values were submitted to statistical analysis. The results showed that the method of storage had no statistically significant influence on marginal microleakage. Microleakage at the cervical wall was significantly greater than that at the axial wall, with 99.9% of certainty. The adhesive systems did not show significant influence on microleakage, in the studied methods of storage. However, there was statistical difference in the Dehydrated group samples, with the use of Prime & Bond 2.1 adhesive, when considering the margins of the restoration (axial and cervical).

Dental Leakage↗

Effect of 1-bottle light-cured adhesive acidity on microleakage of a self-cured composite.

This in vitro study examined the effect of 1-bottle light-cured adhesives with different acidities on the microleakage of a self-cured composite in Class II restorations. Forty-five Class II cavities were prepared on the proximal surfaces of extracted human intact third molars that were randomly assigned to 3 groups (15 cavities in each group). The following adhesives were applied according to the manufacturer's instructions: Single Bond (Group 1), Excite (Group 2) and One-Step (Group 3). The teeth were restored with a combination of a self-cured resin composite (Concise) and a light-cured resin composite (Filtek P60). After thermocycling (500 cycles at 5 degrees C/55 degrees C) and immersion in 2% basic Fushin, the teeth were sectioned and evaluated for microleakage using a stereomicroscope (16x). Microleakage was scored on a scale of 0 to 3. Kruskal-Wallis analysis showed that there was a significant-difference in microleakage values of 3 adhesives with a self-cured composite, and low pH may have contributed to high microleakage values. Also, 2 by 2 comparisons with the Mann-Whitney U-test revealed a significant difference at the p<0.05 level between Groups 1 and 2 and between Groups 2 and 3. However, there was no statistically significant difference between Groups 1 and 3.

Acid Etching, Dental↗

Microleakage in the proximal walls of direct and indirect posterior resin slot restorations.

This study compared the degree of microleakage in the proximal walls of direct and indirect resin slot restorations in relation to the types of dentin bonding systems and the location of gingival margins. Two Class II slot preparations were prepared and restored in each of 60 extracted human molars using direct (Filtek Supreme) and indirect (Tescera ATL) restorative resin materials. Various types of dentin bonding systems, including self-etching (OneStep Plus/Tyrian SPE, iBond, Xeno III) and etch and rinse systems (All-Bond 2, Prime & Bond NT) were used to restore the prepared teeth. The gingival proximal wall was placed apical to the cementoenamel junction (CEJ) in 1 proximal box and coronal to the CEJ in the other. The specimens were stained and evaluated for microleakage using a digital imaging and analysis system. Significant differences were found in the degree of microleakage observed in the various restorative groups. In general, the group restored with indirect resin had less microleakage than the direct resin groups. Factors, such as type of dentin bonding system and location of gingival margins, exert a substantial influence on the degree of microleakage that occurred along the walls of proximal resin restorations.

Acid Etching, Dental↗

Microleakage in conventional and bonded amalgam restorations: influence of cavity volume.

This study verified the relationship between the volume and microleakage of conventional and bonded amalgam restorations. Also, the microleakage influence of intermediate materials, substrates and the direction of sectioning was investigated. Fifty-six bovine incisors were selected. Standard Class V cavities were prepared in buccal and lingual surfaces. For each tooth, two cavity sizes were prepared, corresponding to two cavity volumes: one larger (A) and the other smaller (B). The cervical wall was located in cementum/dentin and the incisal wall in enamel. The teeth were distributed in four groups (n=28) according to the intermediate material employed (glass-ionomer cement, resin cement, adhesive system and copal varnish-control). The materials were applied following manufacturers' directions. After restoration, the teeth were submitted to thermal cycling. They were then immersed in a dye solution and sectioned in two directions inciso-cervical (IC) and mesio-distal (MD) sections to evaluate the microleakage. Data were subjected to non-parametric statistical analysis (Wilcoxon's paired test and Kruskal-Wallis test). No significant difference was found between the two cavity sizes. Leakage in enamel was statistically lower than in the cementum/dentin interface (p < 0.05). In some situations, glass-ionomer or resin cement lined amalgam restorations presented less dye leakage than copal varnish lined restorations (p < 0.05). No significant difference was observed in microleakage between IC or MD sectioning. Within the limitations of this study, it was concluded that cavity size and direction of section were not significant factors for microleakage, while substrate and intermediate materials had a significant effect on the sealing ability in amalgam restorations.

Animals↗

Influence of resin composite shade and location of the gingival margin on the microleakage of posterior restorations.

OBJECTIVE: The objective of this in vitro study was to evaluate the influence of resin composite shade and location of the gingival margin (enamel or dentin) on the microleakage of proximal restorations on posterior teeth. METHODS AND MATERIALS: Sixty freshly extracted human third molars were prepared with standardized Class II box-shaped cavities with proportional size and shape, with distal gingival margins located on the enamel and mesial gingival margins on dentin. The teeth were randomly divided into 6 groups according to resin shade (n=10): G1-Incisal; G2-A1; G3-A2; G4-A3; G5-A3.5; G6-A4. The cavities were restored with a total-etch 1-bottle adhesive system and microhybrid resin composites inserted in 4 increments, light cured for 20 seconds through the occlusal surface, then an additional 60 seconds for each surface. After 1 week of immersion in distilled water, the specimens were thermocycled (500 cycles, 5 degrees -55 degrees C, 30 seconds dwell time), sealed with nail polish and immersed in 0.5% basic fuschin solution for 24 hours. The restorations were sectioned longitudinally, and microleakage was evaluated using a 0-3 score scale. RESULTS: Data were subjected to Kruskal-Wallis and Wilcoxon tests at p<0.05. No statistically significant differences between groups were observed regarding the shade of resin composite (p=0.8570). When margins (enamel or dentin) were considered separately, statistically significant differences were observed between groups (p<0.0001), with enamel margins exhibiting lower degrees of microleakage. CONCLUSION: The variation of resin composite shades utilized in this study did not influence the microleakage of Class II restorations. However, the location of the gingival margin influenced the microleakage.

Acid Etching, Dental↗

Microleakage of a consolidated silver direct filling material.

Microleakage of an experimental direct filling material comprised of a chemically precipitated silver powder that had been surface treated with a dilute acid to promote cold welding upon consolidation was evaluated. Microleakage was compared to both dispersed-phase and spherical amalgam by use of an in vitro gas-diffusion method and in class 5 restorations placed in extracted human teeth. The effect of two cavity varnishes and two dentin adhesives as cavity liners on microleakage was also evaluated using extracted teeth. Microleakage of silver powder consolidated with dental instruments was less than that found with dental amalgam. The use of copal or polyamide cavity varnish resulted in the lowest combination of microleakage on dentin and enamel margins.

Analysis of Variance↗

Microleakage evaluation of pit and fissure sealants done with different procedures, materials, and laser after invasive technique.

This study evaluated the microleakage of pit and fissure sealants after different surface preparation (invasive technique and laser irradiation) and the use of different materials (fluoride resin-filled sealant, resin-modified glass ionomer cement and adhesive system). Eighty-four pre molars were used in this study, which were divided into seven groups. After the accomplishment of the different treatments, these were submitted to thermocycling process and assess for microleakage by examination under an epifluorescent microscope and scored zero to seven. Two specimens of each group were observed under scanning electron microscope (SEM). The results showed that laser irradiation did not lessen microleakage in pit and fissures when using a filled-resin sealant with fluoride or a resin-modified glass ionomer cement. The use of laser irradiation and adhesive system, followed by a resin-filled sealant with fluoride, showed the lowest microleakage scores in pit and fissures. Comparing this group to the resin-modified glass ionomer cement group, there was statistical significance. The use of a adhesive system decreased microleakage when using a fluoride resin-filled sealant with or without previous laser irradiation; although it was not statistically significant.

Analysis of Variance↗

Microleakage of Compoglass-F and Dyract-AP compomers in Class V preparations after salivary contamination.

PURPOSE: The purpose of this study was to investigate the effect of salivary contamination on the microleakage within Class V preparations of teeth restored with either Compoglass-F/Syntac SC and Dyract-AP/Prime and Bond 2.1. METHODS: Class V cavity preparations with occlusal margins in enamel and gingival margins in cementum were prepared on the buccal and lingual surfaces of extracted human permanent molar teeth. Preparations were distributed randomly into 4 treatment groups (N = 16) consisting of the two compomers and their respective bonding agents with and without salivary contamination. After treatment, the samples were stored in tap water for 24 hours, thermocycled, stained with dye, sectioned, and scored for microleakage. RESULTS: Salivary contamination had no significant effect on enamel microleakage but significantly increased both linear and penetrating microleakage versus non-contaminated for both compomer/dentin bonding systems. CONCLUSION: These data indicate salivary contamination adversely effects gingival but not enamel microleakage when Class V restorations are restored with either Compoglass F/Syntac SC or Dyract-AP/Prime and Bond 2.1.

Analysis of Variance↗

Enhanced retention of glass-ionomer sealant by enamel etching: a microleakage and scanning electron microscopic study.

OBJECTIVE: A microleakage study and a scanning electron microscopic investigation were conducted to test whether etching of enamel would improve adhesion of glass-ionomer cement sealants to fissure enamel. METHOD AND MATERIALS: Forty-eight extracted human molars and premolars were divided into 2 equal groups, and their crowns were cleaned with pumice. In group 1 enamel was etched for 45 seconds with 37% phosphoric acid. In group 2, enamel was not etched. Glass-ionomer sealant was applied to all 48 teeth. Twenty teeth from each group were thermocycled in water (120 cycles between 0 degree C and 56 degrees C) and stained with 0.5% methylene blue solution. The remaining 4 teeth from each group served as a control for the scanning electron microscopic evaluation. Twelve teeth from each group were cut into 5 sections, and 12 were cleaved into 3 sections in a buccolingual direction. RESULTS: Statistically significant differences in amounts of microleakage were found between group 1 and group 2. Minimal microleakage was detected in 90% of the etched teeth, whereas extensive microleakage was observed in 85% of nonetched teeth. The scanning electron microscopic evaluation correlated positively with the microleakage observations. The etched teeth revealed a cohesive failure within the sealant material, while the nonetched teeth demonstrated an adhesive failure at the sealant-enamel interface. Observation of the nonthermocycled teeth confirmed those findings. CONCLUSION: Results suggested that etching prior to application enhances the bonding of glass-ionomer sealant to fissure enamel.

Acid Etching, Dental↗