Microleakage at the cervical margin of composite Class II cavities with different restorative techniques

This study evaluated the microleakage at the cervical margins of Class II composite resin restorations restored with different techniques. Slot cavities were prepared on both proximals of 40 unerupted third molars with one cervical margin located above and the other below the cementoenamel junction. The prepared teeth were randomly assigned to four groups and restored using the following techniques: (I) 3-Sited, (II) Directed-Shrinkage, (III) Resin-Modified Glass-Ionomer Cement or a (IV) Flowable Composite as the gingival increment. All restorations were placed with the same bonding agent and composite resin. The difference among the groups was on the first increment and on its insertion and polymerization techniques. After restoration, the teeth were thermocycled and exposed to a dye. Results showed that all the techniques worked well for enamel, with almost no leakage. However, on cementum, all techniques demonstrated moderate to severe leakage.     

The effect of different types of flowable restorative resins on microleakage of Class V cavities

This study evaluated the microleakage of Class V cavities restored with three different types of flowable resin restorative material and compared the effects of using their respective manufacturer's dentin adhesive or a different brand. Class V cavities with the occlusal margin in enamel and the gingival margin in dentin were prepared on the buccal and lingual surfaces of 48 non-carious human molars. The teeth were randomly assigned to three equal groups of 16. The first eight teeth in each group were restored with one of the flowable restorative materials (Filtek Flow, Dyract Flow, Admira Flow) using the manufacturer's recommended dentin adhesive (Single Bond, Prime & Bond NT, Admira Bond), and the remaining eight molars were restored using a different brand of dentin adhesive (Gluma Comfort Bond). The samples were thermocycled 200 times (5 degrees C-55 degrees C) with a one-minute dwell time. They were then immersed in a 2% basic fuchsin solution for 24 hours, sectioned and analyzed by stereomicroscopy. There was no statistically significant difference at the occlusal margins for either restoration used with its respective dentin adhesive. At the gingival margins, there was a significant difference among all groups. Flowable ormocer (Admira Flow/Admira Bond) displayed the least leakage at the gingival margins. When these flowable restoratives were used with a different brand of dentin adhesive, statistically significant differences were observed both on enamel and dentin. None of the restoratives tested fully prevented leakage at the gingival margins. No significant differences in microleakage were observed among the restorative materials used with respect to the manufacturer's dentin adhesive or a different brand except for Admira Flow restorative at the gingival margins. The gingival margins had significantly more microleakage than the occlusal margins (p < 0.05) except in the Admira Flow group, where microleakage at the occlusal and gingival margins was almost equal.     

Effects of three restorative techniques in the bond strength and nanoleakage at gingival wall of Class II restorations subjected to simulated aging

Objective

To evaluate the effects of simulated aging in bond strength and nanoleakage of class II restorations using three different restorative techniques.

Materials and methods

Class II preparations (n?=?12) were restored using: FS — composite resin Filtek Supreme Plus (3M/ESPE); RMGIC + FS — resin-modified glass ionomer cement Vitrebond Plus (3M/ESPE) + FS; and FFS + FS — flowable composite resin Filtek Supreme Plus Flowable (3M ESPE) + FS. The teeth were assigned into two groups: Control and Simulated Aging — Thermal/Mechanical cycling (3,000 cycles, 20–80 °C/500,000 cycles, 50 N). From each tooth, two slabs were assessed to microtensile bond strength test (μTBS) (MPa), and two slabs were prepared for nanoleakage assessment, calculated as penetration along the restoration margin considering the penetration length (%) and as the area of silver nitrate particle deposition (μm²). Data were analyzed by two-way analysis of variance (ANOVA) followed by Tukey’s post hoc test (p?<?0.05).

Results

FS presented the highest μTBS to dentin (22.39?±?7.55 MPa) after simulated aging, while the presence of flowable resin significantly decreased μTBS (14.53?±?11.65 MPa) when compared to no aging condition. Both control and aging groups of RMGIC + FS presented the highest values of silver nitrate penetration (89.90?±?16.31 % and 97.14?±?5.76 %) and deposition area (33.05?±?12.49 and 28.08?±?9.76 μm²). Nanoleakage was not affected by simulated aging.

Conclusions

FS presented higher bond strength and lower nanoleakage and was not affected by simulated aging. Use of flowable resin compromised the bond strength after simulated aging.

Clinical relevance

The use of an intermediate layer did not improve the dentin bond strength neither reduced nanoleakage at the gingival margins of class II restorations under simulated aging conditions.     

A study of microleakage in Class II composite restorations using four different curing techniques

There are several incremental techniques for the placement of posterior composites in Class II cavities that were introduced to overcome clinical failures associated with these restorations. This study evaluated microleakage in Class II cavities restored with four different curing techniques. On 40 non-carious, freshly extracted human premolars, Class II cavities were prepared following a standard pattern in which the mesial cavities had a cervical margin 1.0 mm above the CEJ, and for distal cavities, 1.0 mm below the CEJ. The specimens were randomly divided into four groups. Each cavity surface was conditioned with 35% phosphoric acid and rinsed to remove the excess water, followed by a dental bonding agent (PQ1) being used for all the cavities. The teeth were then restored with a fiber reinforced resin-based composite (Neulite F), using four different techniques: Group 1, metal matrix with wooden wedge; Group 2, transparent matrix with reflective wedge; Group 3, metal matrix with wooden wedge and light tip and Group 4, metal matrix with wooden wedge and bio-glass cylinder. Then, the restorations were finished and polished, rebonded, thermocycled (2000 times, 5 degrees C to 55 degrees C, 30 second dwell time), stained, sectioned vertically and viewed under a stereomicroscope (40x). They were then scored on a 0-4 scale based on microleakage at the gingival margins. The data were analyzed using the Kruskal-Wallis and Mann-Whitney U tests. The results showed that Group 1 demonstrated the most leakage, while the other three groups showed less leakage than Group 1. There was no significant difference between the enamel and dentin gingival margin groups. As a result of these findings, the authors concluded that restoration with metal matrices, using light conducting instruments, results in significantly less microleakage at the gingival margins of Class II resin composite restorations.     

Polymerization shrinkage and microleakage in Class II cavities of various resin composites

This study investigated the polymerization shrinkage of restorative materials and microleakage in the proximal box of Class II restorations. Twenty caries free extracted human molars were prepared on the mesial and distal, making 40 slot cavities. Groups (n=10) were classified as: Group 1: Single bond/Filtek Z-250; Group 2: Single Bond/Filtek Flow/Filtek Z-250; Group 3: Admira Bond/Admira; Group 4: Ariston Liner/Ariston. Dentin bonding systems and resin composites were applied according to the manufacturer's instructions. The specimens were stored in distilled water for one week at 37 degrees C, thermocycled (5 degrees-55 degrees C x 2000), stained with 50% aqueous silver nitrate, immersed in a diluted developer solution (24 hours), rinsed and sectioned in two pieces with a low speed saw (Isomet). Dye penetration (Score 0-4) was determined separately at the occlusal enamel margin and cementoenamel junction. The volumetric polymerization shrinkage of materials was determined with the apparatus of Watts and Cash (Watts Cash, 1991) for 300 seconds. Polymerization shrinkage results were as follows: Filtek Flow (3.5% +/- 0.1) > Admira (2.1% +/- 0.1) = Ariston AT (2.3% +/- 0.1) > Filtek Z-250 (1.8% +/- 0.1) (One-way Anova, post hoc Bonferroni test at p = 0.05 level). No statistical difference was found at the enamel margins for any of the materials (Score 0-1). At the cemento-enamel junction, all test groups showed significantly higher microleakage when compared to the enamel margins (Kruskal-Wallis test, Mann-Whitney U). Dye penetration results at dentin were as follows: Filtek Flow + Filtek Z-250 = Admira < Ariston AT = Filtek Z-250. microleakage than the ion-releasing and hybrid composites lined only with bonding agent at the cementoenamel junction in Class II cavities.     

Influence of marginal bevels on microleakage around Class V cavities bonded with seven self-etching agents

PURPOSE: To evaluate microleakage around Class V resin-based composite restorations in box-shaped cavities with and without marginal bevels, bonded with one of seven self-etching materials and a non-self etching system. METHODS: 120 extracted human premolars were randomly assigned to eight groups for bonding with the following self-etching agents: Prompt-L Pop, Adper Prompt, Clearfil SE, Prime& Bond NT with NRC, Xeno111, One-Up Bond, AdheSe, or Prime & Bond NT using a total etch technique (36% H2PO4). Box cavities were cut in both the lingual and buocal surfaces. The cavities were made with an ISO 010-fissure diamond bur in a water-cooled high-speed handpiece and were approximately 3 mm wide, 1.5 mm deep, and 2.0 mm high. Selected at random, box-shaped cavities were cut with a 0.5 mm bevel in enamel and dentin on one side and on the contra-lateral side, box-shaped cavities were cut without bevels. Each tooth served as its own control. The teeth were thermocycled and the specimens prepared and examined for microleakage using Procion Red as a marker. RESULTS: All gingival margins leaked whether or not a bevel had been placed, when bonded either with a self-etching agent or using a total etch technique with 36% phosphoric acid. There was no significant difference in leakage between the self-etching groups or those using a total etch technique, at the gingival bevel margins, (P= 0.7384) or the gingival non-beveled margins (P= 0.2307; Kruskal-Wallis Test). Microleakage was found with every agent, both occlusally and gingivally, when bonded either with a self-etching agent or using a total-etch technique. There was no significant difference in leakage between the self-etching groups or those using a total etch technique at the enamel bevel margins, (P= 0.9907) or the enamel non-beveled margins (P= 0.9963; Kruskal-Wallis Test).     

Effect of centripetal and incremental methods in Class II composite resin restorations on gingival microleakage

AIM: The aim of this study was to evaluate the microleakage at gingival margins below the cementoenamel junction (CEJ) of Class II composite restorations using various placement techniques. METHODS AND MATERIALS: Sound human maxillary premolars were selected. Eighty slot-style cavities on the mesial or distal surfaces were prepared with the cervical margins located apical to the CEJ. The specimens were divided into two groups based on the restorative technique utilized (centripetal or incremental). Each group was then categorized into two subgroups according to the type of matrix used resulting in a total of four experimental groups as follows: IP=Incremental and Palodent matrix, IT = Incremental and Transparent matrix, CP= Centripetal and Palodent matrix, and CT = Centripetal and Transparent matrix. Following restoration with a total etch adhesive (Single Bond) and a resin composite (Z100), the teeth were thermocycled. Then specimens were immersed in 0.5% basic fuchsin dye for 24 hours at a temperature of 37 degrees C. Sectioned restorations were examined under a stereomicroscope (40X magnification), and the extent of the microleakage was scored and recorded. Data were analyzed using the Kruskal-Wallis non-parametric statistical test (P=0.05). RESULTS: In the four groups of the study no significant differences in the mean rank of microleakage were observed (p>0.05). CONCLUSION: When the gingival margin was located on cementum, the kind of matrix and filling technique did not reduce the microleakage.     

Optical and scanning electron microscope study of gingival microleakage in Class II composite restorations

It has been studied the gingival microleakage and the polymerization contraction gap in composites class II restorations. The influence of two different composites, a microparticle [Heliomolar (Vivadent)] and a high filled one [P-50 (3M)], has been compared with different adhesion systems: a) gingival enamel acid-etch technique. b) Dentinal adhesives [Gluma (Bayer) and Scotchbond 2 (3M)]. c) A adhesive varnish [Dentin Protector (Vivadent)]. The gingival microleakage is only prevented when a microparticle composite [Heliomolar (Vivadent)] and a adhesive varnish [Dentin Protector (Vivadent)] are used together.     

An evaluation of the radiopacity of composite restorative materials used in Class I and Class II cavities

The radiopacity of 28 shades of 18 composite brands, recommended for use in Class I and Class II cavities, and one amalgam were tested in accordance with the instructions in the latest draft standards of ISO for resin-based filling materials. The composition of the inorganic fillers in the materials was analyzed by optical emission spectroscopy. Twelve composites showed radiopacity greater than enamel, for five the radiopacity was lower than that of dentin, and for two materials the radiopacity was between that of enamel and dentin. The optical emission spectroscopy analyses showed a large variety in the composition of the fillers. The elements added to increase radiopacity in the composite materials are barium, strontium, zinc, zirconium, and ytterbium.     

Marginal adaptation of three Class II composite restorative techniques in vitro

The purpose of this study was to evaluate the marginal integrity of three different Class II restorative techniques in vitro. Mesioocclusal (MO) preparations (no bevels) 4 mm x 3 mm x 2 mm were made on 15 freshly extracted human premolars mounted in cold cure acrylic. The preparations were randomly divided into three groups of five: Group I: Direct technique Group II: Indirect single-visit technique Group III: Indirect laboratory technique Group II cavity preparations were duplicated using alginate impression material (Jeltrate Plus, DENTSPLY Caulk) and a polyvinylsiloxane die material (Mach II, Parkell). Group III preparations were duplicated using polyether impression material (Impregum, ESPE) and type IV die stone (G.C. America Inc., Fujirock). All restorations were fabricated with Tetric Ceram (Vivadent-Ivoclar) microhybrid composite according to manufacturers' recommendations. The inlays were cemented using a dual-cure bonding system (All Bond II, Bisco) and a resin-based cement (Variolink, Vivadent-Ivoclar) and polished according to manufacturers' recommendations. The specimens were examined under an environmental scanning electron microscope (Electroscan). None of the samples was sectioned before examination. The width of the largest gap at the gingival margin, between the restorations and preparations, was recorded in microns. The average gap width for each group was the following: Group I: 63.4 +/- 9.06 microns Group II: 73.54 +/- 13.9 microns Group III: 89.58 +/- 18.5 microns Statistical analysis (one-way ANOVA) revealed that a significant difference exists among the three groups (p = 0.03). Students t-tests revealed a statistical significant difference between Groups I and III (p < 0.02), but did not prove significant between Groups I and II (p > 0.10) and Groups II and III (p > 0.05).     

Influence of different restorative techniques on marginal seal of class II composite restorations

Objective

To evaluate the gingival marginal seal in class II composite restorations using different restorative techniques.

Material and Methods

Class II box cavities were prepared in both proximal faces of 32 sound human third molars with gingival margins located in either enamel or dentin/cementum. Restorations were performed as follows: G1 (control): composite, conventional light curing technique; G2: composite, soft-start technique; G3: amalgam/composite association (amalcomp); and G4: resin-modified glass ionomer cement/ composite, open sandwich technique. The restored specimens were thermocycled. Epoxy resin replicas were made and coated for scanning electron microscopy examination. For microleakage evaluation, teeth were coated with nail polish and immersed in dye solution. Teeth were cut in 3 slices and dye penetration was recorded (mm), digitized and analyzed with Image Tool software. Microleakage data were analyzed statistically by non-parametric Kruskal-Wallis and Mann-Whitney tests.

Results

Leakage in enamel was lower than in dentin (p<0.001). G2 exhibited the lowest leakage values (p<0.05) in enamel margins, with no differences between the other groups. In dentin margins, groups G1 and G2 had similar behavior and both showed less leakage (p<0.05) than groups G3 and G4. SEM micrographs revealed different marginal adaptation patterns for the different techniques and for the different substrates.

Conclusion

The soft-start technique showed no leakage in enamel margins and produced similar values to those of the conventional (control) technique for dentin margins.     

Marginal adaptation of Class V restorations using different restorative techniques

This in vitro study compares the marginal adaptation of Class V restorations with margins located half in enamel and half in dentine, which were placed using different restorative techniques. Five operative procedures were evaluated both in saucer-shaped erosion lesions and in box-shaped cavities with bevels in enamel. The five procedures included a composite inlay technique using both the chemically and the light curing versions of a resin based composite cement, a bulk placement technique using a chemically curing composite resin, an incremental technique and an incremental technique combined with a built-up base, using a light curing composite resin. A combination of Gluma/Clearfil served as the dentinal adhesive. The micromorphology of the tooth/restoration interface was analysed before and after thermal cycling; the marginal seal was analysed after thermal cycling only. In the conventional cavities, the restorations showed less leakage, and micromorphologically a better, but statistically insignificant superior marginal adaptation. The inlay technique rendered the best marginal quality in both enamel and dentine before and after thermal cycling. Due to the unique curing characteristics of the chemically cured composite resin and cement resulting in a significantly reduced rigid contraction, the inlays cemented with the chemically curing cement and the restorations placed with the chemically curing composite resin were superior to their light cured counterparts. The built-up base yielding a reduction of the composite mass did not enhance marginal adaptation because of the partial replacement of the strong adhesion to dentine mediated by the Gluma/Clearfil combination by the weaker bond promoted by the etched glass ionomer cement.     

Abrasion of microfill restorative resins in Class 1 cavities

Abstract – Abrasion of Class 1 microfill restorations has been studied over a period of 2 years. The materials used were the commercial products Isomolar (Ivoclar, Liechtenstein) and Silar (3 M Co., U.S.A.). All fillings were placed in permanent mandibular first molars of Copenhagen schoolchildren. The abrasion for Isomolar (29 fillings) was found to be 9.8±10.3 (range −9 to 28) μm per year, and for Silar (27 fillings) 11.8±13.0 (range −5 to 41) μm per year. Statistically no difference could be demonstrated between the two products.     

Prerestorative bleaching: effect on microleakage of Class V cavities.

The effect of bleaching extracted teeth on the microleakage of subsequently placed Class V composite resin restorations was evaluated. Ten extracted premolars were stored in water at 37 degrees C to serve as controls. Ten premolars were exposed to a carbamide peroxide gel for three 2-hour periods per day for 9 days. These specimens were stored in water at 37 degrees C except during treatment periods. Class V cavity preparations were then placed at the cementoenamel junction of the facial and lingual surfaces of all teeth. Half of the teeth of each group were restored with Scotchbond 2/Silux Plus and half were restored with Prisma Universal Bond 3/AP.H. After 24 hours of storage in 37 degrees C water, the teeth were thermally stressed for 100 cycles. Microleakage was assessed by dye penetration. The results demonstrated that prerestorative bleaching did not affect the marginal seal of subsequently placed restorations.