Microleakage in bonded amalgam restorations using different adhesive materials

The aim of this study was to verify the ability of different adhesive materials to prevent microleakage in bonded amalgam restorations. Standard cavities were prepared in both buccal and lingual surfaces of 35 bovine incisors. The gingival wall was located in cementum/dentin and the occlusal wall in enamel. Teeth (n=35) were divided into 5 groups, according to material employed (one glass-ionomer cement, two resin cements, one adhesive system, and Copalex varnish as a control). Following restoration, the teeth were submitted to thermal cycling. The teeth were subsequently immersed in methylene blue dye and sectioned to allow assessment of microleakage. Non-parametric statistical analysis indicated that all materials demonstrated less leakage than the control group (p<0.01). No leakage was found using the resin-modified glass-ionomer cement, which was significantly different from the other adhesive materials (p<0.05). Leakage in enamel was lower than in cementum/dentin margins. It was concluded that bonded amalgam was an effective technique, since all materials prevented microleakage in enamel and cementum/dentin, when compared to the control group, except Panavia in cementum/dentin margins.     

3种银汞黏接剂抗微渗漏的效果研究

目的检验三种银汞黏接剂应用于粘接银汞修复时,其抗微渗漏的能力,寻找一种简单有效的黏接材料。方法选28颗新鲜前磨牙,在其近中及远中邻面制备边长分别是2 mm和4 mm的长方形,使其龈壁位于牙本质-牙骨质界,牙合壁位于牙釉质。28颗前磨牙按黏接材料的不同分为4组:空白对照组,树脂加强玻璃离子水门汀组,玻璃离子水门汀组,树脂型银汞黏接剂组。充填后,37℃水浴7 d,然后浸入亚甲蓝染色液中,37℃恒温染色48 h,统计其微渗漏结果。结果非参数统计显示实验组微渗漏小(P<0.01),树脂加强型玻璃离子组无微渗漏,与其他组有着显著差异(P<0.05),釉质侧的渗漏低于牙本质-牙骨质侧。结论粘接银汞修复是一项有效的技术,并且用树脂加强型玻璃离子作黏接剂有着更有效的防微渗漏效果,值得在临床推广应用。     

Microleakage evaluation in amalgam restorations used with bases.

Marginal leakage in amalgam restorations often precedes the development of secondary caries. One potential way to improve the marginal seal of such restorations, and thus minimize the risk of caries development, is to apply a glass-ionomer base prior to amalgam placement. This study compared microleakage resistance among amalgam restorations placed with and without light-cured glass-ionomer base materials. Preparations were made in extracted human molar teeth. Four groups were studied, including copal varnish, which was used as a control. All specimens were restored with amalgam. Results indicated significantly greater leakage at the cavity wall/base interface for restorations with a copal varnish cavity liner than for those with a glass-ionomer base. Leakage differences among bases were also found at the amalgam/base interface. Best results were obtained with a dual-cure resin-based system. These samples showed minimal leakage at both the cavity wall/base and the base/amalgam interfaces. These findings suggest that light-cured glass-ionomer bases can be effective in the prevention of microleakage in amalgam restorations.     

Microleakage Evaluation in Amalgam Restorations Used with Bases

Marginal leakage in amalgam restorations often precedes the development of secondary caries. One potential way to improve the marginal seal of such restorations, and thus minimize the risk of carles development, is to apply a glassionomer base prior to amalgam placement.
This study compared microleakage resistance among amalgam restorations placed with and without light-cured glass-ionomer base materials. Preparations were made in extracted human molar teeth. Four groups were studied, including copal varnish, which was used as a control. All specimens were restored with amalgam. Results indicated significantly greater leakage at the cavity wall/base interface for restorations with a copal varnish cavity liner than for those with a glass-ionomer base. Leakage differences among bases were also found at the amalgam/base interface. Best results were obtained with a dual-cure resin-based system. These samples showed minimal leakage at both the cavity wall/base and the base/amalgam interfaces. These findings suggest that light-cured glass-ionomer bases can be effective in the prevention of microleakage in amalgam restorations.     

Addition of fresh amalgam to existing amalgam: microleakage study.

The purpose of this in vitro study was to determine whether adhesive lining materials reduce microleakage in amalgam restorations, and to observe the degree of microleakage at the interface between freshly placed (new) and existing (old) amalgam. Forty-eight specimens were used in the experimental groups. The materials used to study microleakage in this investigation were: copal varnish, a dentin bonding agent (Clearfil New Bond), and a 4-META adhesive (Amalgambond). No significant difference in microleakage was found at the interfaces between freshly placed and existing amalgam. Significantly less microleakage was noted in specimens using the 4-META adhesive and the dentin bonding agent as compared to specimens in which no lining material was placed. Significantly less microleakage was noted in specimens using the 4-META adhesive compared to specimens using cavity varnish.     

Addition of Fresh Amalgam to Existing Amalgam: Microleakage Study

The purpose of this in vitro study was to determine whether adhesive lining materials reduce microleakage in amalgam restorations, and to observe the degree of microleakage at the interface between freshly placed (new) and existing (old) amalgam. Forty-eight specimens were used in the experimental groups. The materials used to study microleakage in this investigation were: copal varnish, a dentin bonding agent (Clearfil New Bond), and a 4-META adhesive (Amalgambond). No significant difference in microleakage was found at the interfaces between freshly placed and existing amalgam. Significantly less microleakage was noted in specimens using the 4-META adhesive and the dentin bonding agent as compared to specimens in which no lining material was placed. Significantly less microleakage was noted in specimens using the 4-META adhesive compared to specimens using cavity varnish.     

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.     

Microleakage and SEM interfacial micromorphology of amalgam restorations using three adhesive systems

OBJECTIVE: This study evaluated the microleakage and interfacial micromorphology of Class V cervical amalgam restorations lined with OptiBond, AElitebond, or Panavia 21. METHODS: Unlined amalgams served as control. Cavities were treated with each dentin bonding system according to the manufacturers' instructions and restored with Tytin non-gamma 2 spherical amalgam. After one week of storage in tap water at 37 degrees C, the specimens were thermocycled (1000 cycles, 6-60 degrees C, 30s dwell time). Microleakage was assessed by means of basic fuchsin dye penetration and recorded according to an ordinal scale. RESULTS: None of the systems tested in this study completely eliminated microleakage. Kruskal-Wallis one-way ANOVA and Mann-Whitney U test found that on the occlusal wall, Panavia 21 and the control group had the least leakage (P<0.05). No statistically significant differences were found at dentin margins (P>0.05). Wilcoxon matched pairs signed rank test found that Panavia 21 and the control group had less leakage at the occlusal than at the dentin margins (P<0.05); when AElitebond and OptiBond groups were evaluated, microleakage at the enamel and at the dentin margins was similar for each group. With the adhesive systems, perhaps the hydrophilic bonding agents incorporated the dye during specimen immersion and/or sectioning. CONCLUSIONS: The use of adhesives may not be as worthy as resin cements for sealing and bonding amalgam restorations to enamel and dentin.     

Effect of a resin-based desensitizing agent and a self-etching dentin adhesive on marginal leakage of amalgam restorations

AIM: The purpose of this study was to compare the marginal leakage of Class II amalgam restorations whose preparations were lined with a resin-based desensitizing agent, a self-etching adhesive system, and copal varnish. METHODS AND MATERIALS: Fifty-six freshly extracted human premolar teeth were divided into four groups. A Class II preparation was prepared with only a proximal box on the mesial and distal surfaces of each tooth. The cavities in one group were lined with a desensitizing agent (VivaSens) and a second group with an adhesive (Clearfil S3 Bond). A third group was lined with copal varnish (Copalite) and a fourth group was used as the control without any cavity liner. Spherical high copper amalgam was hand-condensed into each preparation, specimens were thermocycled, stained, and sectioned. Microleakage was graded using a stereomicroscope. Microleakage scores were calculated and analyzed using the Kruskal Wallis and the Mann-Whitney tests (alpha=0.05). RESULTS: Less microleakage was indicated with the VivaSens liner when compared with the other groups (P<0.05). Clearfil S3 Bond showed less microleakage than the control group (P<0.05), but the leakage with copal varnish and Clearfil S3 Bond was similar (P>0.05). CONCLUSION: VivaSens reduced the microleakage of Class II high copper amalgam restorations significantly more than the Clearfil S3 Bond and copal varnish.     

The influence of matrix use on microleakage in Class 5 glass-ionomer restorations.

This in vitro study examined the relationship of matrix use to microleakage in class 5 Ketal-Fil glass-ionomer restorations. Class 5 glass-ionomer restorations were placed on the facial and lingual surfaces of 40 extracted human molars. The occlusal margin was located on enamel, and the cervical margin was located on cementum or dentin. Each tooth had one restoration placed with and without the aid of a soft metal matrix. Specimens were thermocycled (1234 cycles, 6 degrees C -60 degrees C, 30-second dwell time) and immersed in 5% methylene blue dye for four hours. The teeth were sectioned occlusogingivally through the center of each restoration, viewed with an optical microscope (X10), and each restoration was scored for dye penetration around the cavity walls. The enamel and cementum margins were scored separately for the extent of marginal leakage. No difference in leakage was found between restorations placed with or without a matrix (P > 0.05). Enamel restorations leaked significantly less than nonenamel margins, regardless of matrix use (P > 0.05).     

Microleakage in amalgam restorations: influence of cavity cleanser solutions and anticariogenic agents

This study evaluated in vitro the influence of five solutions used to treat cavity preparations on microleakage of amalgam restorations. Seventy-two standard Class V cavities were prepared in buccal and lingual surfaces of 36 recently extracted human third molars. The cervical wall was located in cementum and the occlusal wall was located in enamel. Specimens were randomly divided into six groups (n=12) according to the solution employed to treat the cavities: Group I-2.5% sodium hypochlorite; Group II-Calcium hydroxide solution; Group III-1.23% Acidulated phosphate fluoride; Group IV-2% digluconate of chlorhexidine; Group V-anionic detergent solution (1.25% sodium lauryl sulfate) and Group VI-control group. The solutions were applied for one minute, followed by washing and drying. Two coats of copal varnish were applied in each cavity. The cavities were filled with capsuled amalgam GS-80 (SDI). After finishing and polishing, the specimens were submitted for thermal cycling followed by immersion in methylene blue. Then, the specimens were sectioned and microleakage was evaluated based on a standard ranking under magnification (40x). Data were subjected to statistical analysis using non-parametric tests. Results of the study concluded that leakage was higher in cementum than enamel (p<0.01). The substances employed have no influence on microleakage except for sodium hypochlorite, which increased leakage values in enamel (p<0.05).     

Evaluation of the cervical integrity during occlusal loading of Class II restorations

There are many concerns regarding the clinical behavior of packable composite restorations in Class II cavities, particularly when those restorations are subjected to axial mechanical loads. This study evaluated microleakage in vitro in proximal vertical "slot"-type cavities with walls located in enamel and dentin, filled with packable composite, associated or not associated with a flowable composite, a reinforced light-curing glass-ionomer or a compomer, after being submitted to occlusal load cycling. These preparations were subjected to either occlusal load cycling or no occlusal load cycling. Eighty human molars with enamel and dentin margins were treated with standardized cavity preparations (proximal vertical "slot" preparations). After completing the filling process using a packable composite (Filtek P60) with or without a cervical increment of flowable composite (Filtek flow), light-curing glass-ionomer (Vitremer) or compomer (Dyract AP), the molars were separated into two groups: control (without occlusal loading) and test, in which 4,000 one-second cycles of 150 N occlusal loading were applied. All 80 teeth were submitted to a microleakage test, then evaluated utilizing silver nitrate dye penetration. Significant statistical differences (Wilcoxon test, p<0.05) in the amount of leakage in enamel and dentin were found in both the control and test groups. After a paired comparison of the control and test groups, a significant statistical difference was found at the enamel level (Mann-Whitney test, p<0.05). In dentin, the only statistically significant difference found was the relation to the flow material. The Kruskal-Wallis test did not detect any statistically significant difference in the amount of leakage among the four materials studied, with a 5% level of significance for both enamel and dentin. Based on this data, it was concluded that restorations with margins located in dentin had greater microleakage than those restorations with margins located in enamel. When the samples were submitted to occlusal loading, they were negatively influenced, which increased microleakage values in enamel and dentin. There was no statistically significant difference among the four tested materials, when comparing their performance.     

In vivo and in vitro evaluations of microleakage around Class I amalgam and composite restorations

This study evaluated and compared microleakage values of in vivo and in vitro placed Class I amalgam restorations with or without three different lining materials and posterior composite restorations with two dentin bonding agents. For the in vivo group, 72 standardized Class I cavities were prepared on the occlusal surfaces of molars scheduled for extraction. The test groups (n = 12) were: amalgam without lining (A), amalgam with cavity varnish (A+C), amalgam with Clearfil SE Bond (A+CSE), amalgam with Clearfil 2V (A+C2V), composite with Clearfil SE Bond (C+CSE) and composite with Protect Bond (C+PB). The restored teeth were extracted after seven days. The same grouping, materials and techniques were used in 72 extracted molars for the in-vitro part of the study. The specimens were immersed in basic fuchsin for 24 hours and sectioned. Microleakage was examined and scored at 20x magnification. Statistical analyses were performed with the Kruskal-Wallis and Mann-Whitney U-tests with the 5% level of significance. Overall, the in vivo and in vitro test groups were not different from each other. No significant differences in microleakage values were observed between the unlined and lined amalgam groups (p > 0.05). However, since lined amalgam restorations did not reveal any marginal leakage, the application of an adhesive bonding material under the amalgam restorations can be considered. In general, cavity varnish was not as effective as adhesive bonding agents in preventing microleakage in amalgam restorations. Composite restorations demonstrated higher leakage values than amalgam restorations (p < 0.05), except for A+C (p > 0.05) in the in vivo group. There was no significant difference between the two composite groups for in vitro and in vivo conditions (p > 0.05).     

Microleakage in MOD resin composite with three dentin bonding agents

The extent of microleakage under MOD composites was studied when an aluminum oxalate dentin bonding agent (Tenure), a phosphonated resin bonding agent (Bondlite), and a glass-ionomer cement (Ketac Silver) were used. Three groups of 10 extracted molars were prepared with MOD cavities; one box ended on enamel, the other on cementum. In Group 1, Bondlite was applied to dentin and etched enamel before the sample was restored with a light-cured hybrid composite. In Group 2, a 2-mm increment of Ketac Silver was placed in each box before Bondlite and composite. In Group 3, Tenure was applied to dentin before being restored. Teeth were thermal-cycled, stained in silver nitrate, sectioned, and scored for microleakage. Microleakage along the gingival floor was significantly less at enamel margins than at cementum margins in all three groups. All groups showed severe marginal microleakage on cementum.     

Microleakage of bonded amalgam restorations: effect of thermal cycling

This study examined the effect of thermal cycling on the microleakage of bonded amalgam restorations. Three dental amalgam alloys and a gallium alloy were tested with two adhesive resin systems and copal varnish as a control. Class V cavity preparations were prepared on 168 freshly extracted premolars or molars. The preparations were placed parallel to and 1.0 mm occlusal to the cementoenamel junction (CEJ). Four groups of 42 teeth each were treated with one of the following adhesive dentin systems: Bond-It, All-Bond 2/Resinomer or a copal varnish (Copalite). The four groups of 42 teeth each were then restored with one of three dental amalgams: Orosphere Plus, Indiloy, Oralloy or a Gallium alloy (Galloy), resulting in 12 test groups of 14 teeth each. The specimens were stored in double distilled water at 37 degrees C for 24 hours. Final contouring and polishing of the restorations were performed under water spray. Half of the restorations in each group were thermocycled for 3000 cycles (5 degrees C-37 degrees C-55 degrees C-37 degrees C) with a dwell time of 15 sec at each temperature. The other half were stored in double distilled water at 37 degrees C for 24 hours. Then all 168 restorations were stained with dye, sectioned and scored for microleakage. Results showed that the adhesive dentin systems reduced microleakage in amalgam restorations compared to copal varnish only in non-thermocycled specimens. Statistical analysis of the results showed that there was an extremely significant difference (p < 0.001) in microleakage between the non-thermocycled and the thermocycled specimens in all test groups, whereas, there was no significant difference (p > 0.05) among thermocycled specimens. The reduction of microleakage was not significantly different between Bond-It and All-Bond 2/Resinomer in non-thermocycled specimens. Oralloy showed the most microleakage in the non-thermocycled groups when compared to the other alloys using the same adhesive liner.     

Microleakage of various cementing agents for full cast crowns.

OBJECTIVES: To evaluate microleakage and marginal gaps in full cast crown restorations bonded with six different types of cementing agents. METHODS: Sixty non-carious human premolars and molars were prepared in a standardized manner for full cast crown restorations. The mesial and distal margins were located in dentin, while the vestibular and palatal/lingual margins were located in enamel. Crowns were made from a high-gold alloy using a standardized technique. The specimens were randomized to six groups of cementing agents: one zinc-phosphate cement (Harvard cement), one conventional glass-ionomer cement (Fuji I), one resin-modified glass-ionomer cement (Fuji Plus), two standard resin cements (RelyX ARC, Panavia F), and one self-adhesive universal resin cement (RelyX Unicem). After 4 weeks of storage in distilled water at 37 degrees C, the specimens were subjected to 5000 thermocycles ranging from 5 to 55 degrees C. Then, they were placed in a silver nitrate solution, embedded in resin blocks, and vertically cut in buccolingual and mesiodistal direction. Subsequently, the objects were evaluated for microleakage and marginal gap using a high-resolution digital microscope camera. RESULTS: A number of inter-group differences were statistically significant. RelyX Unicem showed the smallest degree of microleakage both in enamel and in dentin. Panavia F und RelyX Unicem were associated with significantly larger marginal gaps than all other cementing agents. No association was observed between microleakage and marginal gap other than a weak direct correlation when using Harvard cement on enamel. SIGNIFICANCE: The cementing agents investigated revealed different sealing abilities. These differences were not associated with specific types of materials.     

Microleakage of Class V restorations using two different compomer systems: an in vitro study

This study compared the marginal microleakage of Class V cavities restored with Dyract-AP and F2000. Forty Class V cavity preparations were performed on extracted human teeth. As a negative control, twenty teeth were used without Class V preparations. The apical foramina of the teeth were sealed with a layer of varnish and amalgam restorations. Class V cavity preparations with occlusal margins in enamel, and gingival margins in cementum or dentin that measured approximately three millimeters in width (gingival-occlusal) and length (mesial-distal), were prepared on the buccal surface of the teeth. Samples were divided randomly into 2 groups of 15, and restored per manufacturer's instructions using experimental primer/conditioner (PCC, D/C) and Single Bond Adhesive (3M). All restorations were polished with an abrasive finishing kit. After storage in 37 degrees C water for 24 hours, all specimens were thermocycled between 5 degrees C and 55 degrees C for 500 cycles with a 30-second dwell time, followed by immersion in 0.2% basic fucsine for 24 hours. Teeth were then embedded in cold cure acrylic resin, sectioned longitudinally, and the dye penetration at the enamel and cementum margins were scored at 30x magnification. Evaluations were rated from 0 to 3 (0 = no leakage; 1 = dye penetration up to one-half of the preparation depth; 2 = dye penetration more than one-half preparation depth, but less than the axial wall; 3 = dye penetration along the axial wall). Both F-2000 and Dyract-AP indicated no leakage in the enamel margins. Dyract-AP showed no leakage at either the enamel or dentin margins. Fisher's Exact Test revealed that this difference in dentin margins was statistically significant (p < 0.05). Under the given conditions, Dyract-AP and F-2000 demonstrated resistance to microleakage in enamel, and showed Dyract-AP to be more resistant to microleakage in dentin than F-2000.     

Influence of flowable liner and margin location on microleakage of conventional and packable class II resin composites

This in vitro study evaluated gingival wall microleakage in packable and microhybrid conventional composite restorations with and without a flowable composite liner. Each group was evaluated with gingival margins situated in both enamel and cementum/dentin. Two hundred and forty Class II cavities were prepared in extracted third molars, half with gingival margins in enamel and half with margins in dentin/cementum. In groups of 30, restoration was undertaken with packable alone (3M Filtek P60), conventional alone (3M Z250), packable plus flowable liner (3M Filtek Flow) and conventional plus flowable liner. All used 37% phosphoric acid etch and Scotchbond 1 (3M) as the bonding system. After restoration, the teeth were thermocycled (between 5 degrees C, 37 degrees C and 60 degrees C) 1,500 times, soaked in 0.1% methylene blue, sectioned and microleakage from the gingival margin scored. Statistical analysis was performed using Kruskal Wallis and Mann-Whitney U tests. There was no significant difference between systems in terms of leakage scores when gingival margins were situated in enamel (p=0.70). All restorations with margins in cementum/dentin leaked significantly more than those with margins in enamel (p<0.001). There was no significant difference between leakage scores of 3M Z250 and Filtek P60 with cementum/dentin gingival margins (p=0.68). Use of a flowable composite liner (3M Filtek Flow) against cementum/dentin was associated with increased microleakage (p<0.001). In this study, leakage scores suggest that gingival margins should be placed in enamel. The conventional and packable resin composites tested were not associated with differences in microleakage. Leakage data do not support the use of flowable resin composite linings in Class II resin composite restorations.     

Secondary caries formation in vitro around glass ionomer-lined amalgam and composite restorations

SUMMARY The aim of this in vitro secondary caries study was to examine the glass-ionomer liner's effect on wall-lesion inhibition when a conventional and a light-cured glass ionomer liner was placed under amalgam and composite resin restorations. Class V preparations in extracted upper premolars were used and ten restorations were used for each of the following groups: (i) two layers of copal varnish and amalgam; (ii) conventional glass-ionomer and amalgam; (iii) light-cured glass-ionomer and amalgam; (iv) bonding agent and light-cured composite resin; (v) conventional glass-ionomer, bonding agent and light-cured composite resin; (vi) light-cured glass-ionomer, extended 0.3 mm short of the enamel margin bonding agent and light-cured composite resin; and (vii) light-cured glass-ionomer, extended 1 mm short of the enamel margin, bonding agent and light-cured composite resin. The teeth were thermocycled and artificial caries were created using an acid-gel. The results of this study showed that artificial recurrent caries can be reduced significantly ( P < 0.05) with a glass-ionomer liner under amalgam restorations. The results also showed that when the light-cured glass-ionomer liner was placed 0.3 mm from the cavo-surface margin under composite resin restoration, the artificial recurrent caries reduced significantly ( P < 0.05).     

An in vitro comparison of marginal microleakage of alternative restorative treatment and conventional glass ionomer restorations in extracted permanent molars

PURPOSE: The objective of this study was to compare the marginal leakage of cervical restorations made using alternative restorative treatment (ART) and conventional glass ionomer restorations. METHODS: Sixteen permanent maxillary and mandibular first and second molars extracted for periodontal reasons with Class V carious dentin on the buccal surfaces were prepared using ART while a second set of 29 noncarious molars had Class V preparations made with a high-speed handpiece. The occlusal margin was located in the enamel, and the gingival margin was located in the dentin/cementum. All teeth were restored with glass ionomer cement (GIC). The teeth were thermally stressed for 300 cycles and stained with methylene blue. Samples were sectioned and evaluated for microleakage. RESULTS: One-way analysis of variance on ranks revealed no significant difference in leakage at both the dentin and enamel margins between the conventional and ART groups. The microleakage at the dentin margin, however, was significantly greater (P < .001) than at the enamel margins in the conventional group. CONCLUSION: Alternative restorative treatment with GIC provides enamel and dentin margins that show comparable marginal leakage to conventionally restored permanent teeth. For the conventional restorations, leakage at the dentin margins occurs to a significantly higher extent than at the enamel margins.