Flowable Composite Liner Research Articles

Effect of flowable composite liner and glass ionomer liner on class II gingival marginal adaptation of direct composite restorations with different bonding strategies

ObjectivesThe purpose of the present study was to comparatively evaluate the effect of flowable composite resin liner and resin modified glass ionomer liner on gingival marginal adaptation of class II cavities restored using three bonding agents (Single Bond 3M ESPE, One Coat Self Etching Bond Coltene Whaledent; Adper Easy Bond Self-Etch Adhesive 3M ESPE) and respective composite resins, under cyclic loading. The marginal adaptation was evaluated in terms of ‘continuous margin’ (CM) at the gingival margin. Materials and methodsNinety class II cavities with margins extending 1mm below the cement–enamel junction were prepared in extracted mandibular third molars. The samples were divided into three groups: no liner placement; 0.5–1mm thick flowable resin liner placement (Filtek Z350 XT flowable resin) on gingival floor and; light cure glass ionomer (Ketac N100) liner. The groups were further subdivided into three sub-groups on the basis of the bonding agents used. Cavities were restored with composite resins (Z350 for Single Bond and Adper Easy Bond; and Synergy D6 Universal, for One Coat Self Etching Bond) in 2mm increments and the samples were mechanically loaded (60N, 1,50,000 cycles). Marginal adaptation was evaluated using a low vacuum scanning electron microscope. Statistical analysis was done with two way ANOVA with Holm–Sidak's correction for multiple comparisons. ResultsPlacement of flowable composite liner significantly improved the CM values of Single Bond (78±11%) and One Coat Self Etching Bond (77±9%) compared with no liner group, but the values of CM of Adper Easy Bond were not improved (61±12%). Placement of glass ionomer liner significantly improved the values of CM in all the sub-groups (78±9%, 72±10% and 77±10% for Single Bond, One Coat Self Etching Bond & Adper Easy Bond respectively) compared with no liner group. ConclusionsPlacement of liners improved the values of ‘continuous margin’ in the gingival floor of the proximal cavities restored with composite resins using different bonding agent. Clinical relevancePlacement of flowable composite liner or glass ionomer liner will improve the marginal integrity of composite restorations using etch-and-rinse and two bottle-two step self etch adhesives. To improve the marginal integrity of a single bottle adhesive, glass ionomer liner should be applied.

A Comparative Evaluation of Microleakage in Class V Composite Restorations

Aim. To compare and evaluate the microleakage in class V lesions restored with composite resin with and without liner and injectable nanohybrid composite resin. Materials and Methodology. 60 class V cavities were prepared in 30 freshly extracted teeth. After etching and application of bonding agents these cavities were divided into three groups: Group A (n = 20)—restored with composite resin, Group B (n = 20)—flowable composite resin liner + composite resin, and Group C (n = 20)—restored with injectable composite resin. After curing all the specimens were subjected to thermocycling and cyclic loading. Specimens were stained with 0.5% basic fuchsin and evaluated for dye penetration. Results. Results are subjected to Kruskal Wallis and Wilcoxon test. Conclusion. Within the limitations of this study, none of the three materials were free from microleakage. All the three materials showed more microleakage at gingival margins compared to occlusal margins. Among all the groups G-ænial Flo showed the least microleakage at the gingival wall.

Microleakage evaluation in restorations using different resin composite insertion techniques and liners in preparations with high c-factor – An in vitro study

ObjectiveTo evaluate microleakage in the enamel and cementum walls in preparations with high C factor, using three resin composite insertion techniques and two liners. Materials & methodsStandard class V cavities were prepared in buccal and lingual aspects of 36 caries free, extracted premolars. The teeth were randomly assigned to three groups of 12 each corresponding to three different insertion techniques (1) Oblique insertion (2) Horizontal insertion and (3) Bulk insertion and then subdivided into three groups of four each depending on the type of liner used (1) no liner (2) RMGIC liner (GC fuji II LC) and (3) Flowable composite liner (Tetric flow, Ivoclar vivadent). The preparations were etched and restored with an Adhesive (adper single bond 2 3M ESPE), Liner (except for the no liner group) and Microhybrid resin composite (Z100, 3M ESPE). Specimens were isolated with nail varnish except for 2mm wide rim around the restoration, thermocycled (1000 thermal cycles, 5/55°C, 30s dwell time) and then immersed in an aqueous solution of 50wt% silver nitrate for 24h followed by 8h in a photo developing solution and evaluated for microleakage using a stereomicroscope on an ordinal scale of 0–4. The microleakage scores were analyzed by using the chi square test. ResultsOblique incremental technique coupled with the use of flowable composite liner gave better results when compared to other groups at the cementum margins. ConclusionNone of the insertion techniques nor the use of liners were able to eliminate microleakage completely; however the use of the oblique insertion technique coupled with the use of flowable composite liner gave better results.

The effects of glass ionomer and flowable composite liners on the fracture resistance of open-sandwich class II restorations

This in vitro study aimed to investigate the effects of glass-ionomer and flowable composite liners on the fracture resistance of Class II amalgam and composite restorations. Group 1 cavities were restored with amalgam and Group 4 cavities with nanofill composite after the application of a dentin-bonding agent. For the remaining groups, light-cured-glass-ionomer liner was used in a gingival floor proximal box (Groups 2, 5) or flowable composite was used as a liner (Groups 3, 6), the remainder of the cavity was restored with amalgam (Groups 2, 3) or composite (Groups 5, 6). The restorations were loaded in compression to failure. The data was analyzed using Tukey's multiple comparison test. The fracture resistance was significantly higher (p<0.05) in Group 3 than in all other groups, except Group 2 (p>0.05). Flowable composite, glass-ionomer liners increased the fracture resistance of open-sandwich Class II amalgam restorations.

Microtensile bond strength of indirect composite restorations using different combinations of resin coating technique

The aim of this study was to evaluate microtensile bond strength (μ-TBS) and failure mode of indirect composite restorations bonded to dentin using different combinations of Resin-Coating (RC) after thermal and load cycling. Thirty and distal surface). The 70 cavities were distributed in 7 groups according to the coating materials: G1:Etch-rinse 2steps (SB2); G2:Etch-rinse 2steps/Hydrophobic-monomer (SB2/B); G3:Etch-rinse 2steps/Flowable composite resin (SB2/FL); G4:Self-etch 1step (CS3); G5:Self-etch 1step/Hydrophobic monomer (CS3/B); G6:Self-etch1step/Flowable composite resin liner (CS3/PL), G7:Self-etch 2step/Flowable composite resin liner (CSEB/PL). The cavities were molded with a using the Sinfony composite system (3M/ESPE) and were cemented with resin luting cement (Rely X ARC system). After 24 hours, the teeth were submitted to thermocycling (2,000C/5-55°C) and load cycling (250,000C/30N). After, the restored teeth were sectioned in to beams and μ-TBS were measured. The data were analyzed with ANOVA and Tukey test (p<0.05). In addition failure mode pattern was determined by scanning electrical microscopy. Bond strength were mode exhibited dentin exposure. The groups CSEB/PL and CS3/B showed the highest values of bond strength and the failure mode reveal CSEB/PL exhibited better performance since doesn’t present any fracture kind A.

SEM evaluation of gap at the resin dentin interface in Class II composite resin restoration: an in vitro study

Introduction: Composite resins have become one of the most commonly used direct restorative materials for anterior and posterior teeth.Objectives: To observe and analyze the gap at the resin dentin interface in class II cavities restored with light cure composite resin in four experimental groups employing 37% phosphoric acid or self etching monomers and restored with /without light cure flowable composite resin.Methods: 40 sound maxillary first premolars, extracted due to orthodontic reasons was taken, distoproximal cavities were prepared and divided into 4 groups. Teeth of Group 1 was etched by 37% Phosphoric acid and light cure flowable composite resin was used, in group 2 ,two coats of self etching acidic monomer were applied and light cure flowable composite resin was used. Teeth of group 3 was etched with 37% phosphoric acid and restored without light cure flowable composite resin and in group 4, two coats of self etching acidic monomer were applied and restored without using light cure flowable composite resin material. Thermocycling was done after finishing and polishing and viewed under scanning electron microscope to observe and analyze the gap between tooth and the restoration.Result: Gap was observed at dentin-composite resin interface in all 4 groups. Results were evaluated by F-test and Manwhitney U test. No statistically significant difference was found.Conclusion: Use of flowable composite resin liner and the etching technique do not have any influence on the gap.DOI: http://dx.doi.org/10.3126/hren.v10i2.6571 Health Renaissance 2012; Vol 10 (No.2); 98-104

Effect of layering methods, composite type, and flowable liner on the polymerization shrinkage stress of light cured composites

ObjectivesThe aim of this study was to investigate the effect of layering methods, flowable composite liner and use of low shrinkage silorane-based composite on the polymerization shrinkage stress of light cured composites. MethodsAluminum blocks were used to prepare MOD cavities and divided into four groups. A universal hybrid methacrylate-based composite (Z250), a flowable composite (Z350 flowable), and a silorane-based composite (P90) were used to fill the cavities. Cavities were restored using four different filling protocols. Group 1 was filled in bulk with Z250, group 2 was restored by an increment technique with the same composite, group 3 by an increment technique with Z250 and a Z350 flowable lining, and group 4 was restored by an increment technique with P90. The axial shrinkage strain and flexural modulus of the three composites were determined, and cuspal deflection of each group was measured with LVDT probes and compared among groups using ANOVA and Tukey's post hoc test (α=0.05). ResultsThe axial shrinkage strains of P90, Z250, and Z350 flowable were 1.09 (0.11), 2.29 (0.06), and 4.12 (0.08)%, respectively. The flexural modulus of P90 was 10.1 (0.9), Z250 was 13.6 (2.0), and that of Z350 flowable was 7.6 (0.9) GPa. The cuspal deflections at 33min in groups 1–4 were 18.2 (1.54), 14.5 (0.47), 16.2 (1.10), and 6.6 (0.44) μm, respectively. The incremental filling technique yielded significantly lower cuspal deflection than the bulk filling technique. Flowable composite lining under universal composite (Z250) layering showed higher cuspal deflection than that without flowable composite lining. Silorane-based (P90) composite exhibited lower cuspal deflection than metacrylate based (Z250) composite. SignificanceCuspal deflection resulting from polymerization shrinkage stress may be reduced by an incremental filling technique and by the use of low shrinking composite to obtain optimal clinical outcomes. Flowable composite lining under conventional composite layering did not reduce polymerization shrinkage stress as assessed by cuspal deflection.

A comparative study of shear bond strength of two adhesive liners to nanocomposite

Aim: To compare the shear bond strength of resin-modified glass ionomer and nano-filled flowable composite liners to nanocomposite restorative material. Materials and Methods: In this in vitro study, 24 specimens were prepared in acrylic blocks for the study with 12 in each group. Group I consisted of resin-modified glass ionomer liner (GC Fuji II LC Improved) bonded to a cylinder of nanocomposite (Z350 Universal Restorative) whereas in Group II flowable composite liner (Filtek Z350 Flowable Restorative) was bonded to a cylinder of nanocomposite (Z350 Universal Restorative). Shear bond strength was determined using Instron Universal testing machine. Student's independent sample t test was used for analysis. Results: The mean shear bond strength value of Group I was greater than Group II and the difference was statistically significant (P = 0.001). Conclusion: Resin-modified glass ionomer appears to be a more compatible liner under nanocomposite restoration than flowable composite as it exhibited significantly higher shear bond strength.Clinical Relevance to Interdisciplinary DentistryResin-modified glass ionomer and flowable composites have been used as liners under resin composite restorations in both primary and permanent teeth to compensate for their polymerization shrinkage.Adequate bonding of liners to composites is as important as bonding to dentin for the success of this technique.Bonding of resin-modified glass ionomer liner to nanocomposite restorative material is better than flowable composite liner and hence should be preferred over flowable composite as a liner.

Evaluation of the influence of flowable liner and two different adhesive systems on the microleakage of packable composite resin

Aim: The aim of the study was to evaluate the microleakage of a packable resin composite using two adhesive systems (self-etch and total-etch) with and without a flowable liner. Materials and Methods: Class II cavities were prepared on 50 human molars, with standardized dimensions. The teeth were divided into five groups. In group I, the cavities were total-etched with phosphoric acid and bonded with an Adper single bond and then restored with a packable resin composite. In group II, the cavities were total-etched, bonded with an Adper single bond and a flowable resin composite was placed as a liner and restored with a packable resin composite. In group III, self-etching adhesive was used instead of total-etch and a procedure similar to group II was performed. In group IV, a procedure similar to group III was performed, except with the placement of a flowable resin composite liner. Group V served as a control where neither adhesive nor a flowable liner was used. All the samples were placed in a dye for 24 hours and examined for leakage. Results: Packable resin composite, when used alone with self-etch adhesive, demonstrated minimum microleakage when compared to the total-etch system (P = 0.30). The lining of class II cavities with a flowable resin composite, followed by packable restoration, demonstrated higher leakage values than when the packable resin composite was used alone (P = 0.001). Conclusion: The use of a self-etch adhesive system was superior to the total-etch system when the cavities were restored with a combination of a flowable resin composite liner, overlaid with a packable resin composite.Clinical Relevance to Interdisciplinary Dentistry A flowable resin composite can be used as a liner material between dentin and a packable resin composite to reduce microleakage. Use of a proper adhesive system is one of the key factors in reducing microleakage in packable composite resin.

The influence of flowable composite liner on microleakageof class II packable composite resin restoration withdifferent application techniques (Comparative study)

Background: This in vitro study was conducted to evaluate and compare the influence of flowable composite and different application techniques of class II packable composite restoration on dentinal leakage. Materials and methods: Thirty human freshly-extracted Maxillary premolars were selected for this study. Conventional Class II MOD cavities were prepared in the sample teeth which were then divided into five groups .Each group consist of ten boxes either MO or DO according to the restorative procedure used except group A which consist of twenty boxes(ten teeth with MOD amalgam restoration). Group A: ten teeth where restored by amalgam- (SDI Australia) high strength admix amalgam type.Group B: ten teeth in which the mesio-occlusal (MO) sides were restored by {adhesive + flowable composite + one bulk packable composite (Filtek P60)}. Group C: ten teeth in which the disto-occlusal (DO) sides were restored by {adhesive +one bulk packable composite, (Filtek P60)}.Group D: ten teeth in which the mesio-occlusal (MO) sides were restored by {adhesive + flowable composite + successive build up technique for packable composite, (Filtek P60)}. Group E: ten teeth in which the disto-occlusal (DO) sides were restored by {adhesive+ successive build up technique for packable composite, (Filtek P60)}. After thermocycling and immersion in 2% methylene blue, the teeth were sectioned longitudinally mesio-occluso-distal and dye penetration was evaluated using a stereomicrscope, microleakage was recorded in mm. Results and Conclusions: ANOVA test and least significant difference (LSD) test were used to analyze the results, and the results showed that the use of flowable composite resin as a liner with packable composite resin decreases the amount of dentinal microleakage, and the restorative technique of packable composite whether it is bulk build up technique, or incremental successive build up technique has no difference on the improvement of microleakge value, and the packable resin composite restoration whatever applied with different application techniques or restored with or without flowable composite it still had or scored higher microleakage than amalgam restoration.

In vitro evaluation of microleakage of class II packable composite resin restorations using flowable composite and resin modified glass ionomers as intermediate layers

Aim and Objectives:To evaluate the cervical marginal microleakage of class II packable composite resin restorations using flowable composite and resin modified glass ionomer as intermediate layers and whether the difference in the thickness of these intermediate layers would influence the microleakage.Materials and Methods:Standardized class II box only cavities (4 mm bucco lingual width 2 mm mesio distal depth with the gingival margin 1 mm above the cemento-enamel junction (CEJ) were restored as follows: Group A Restoration with packable composite alone, Group B, Subgroup 1, 1 mm flowable composite liner + packable composite, Sub Group 2, 2 mm flowable composite liner + packable composite, Group C, Subgroup 1, 1 mm resin modified glass ionomer cement (RMGIC) liner + packable composite, Sub Group 2, 2 mm RMGIC liner + packable composite, The specimens were thermocycled, stained with methylene blue, sectioned to evaluate the dye penetration. Data were analyzed using Kruskall Wallis Test and Mann Whitney U test.Results:There was no statistically significant difference between the groups. The difference in the thickness of the intermediate layers did not influence the microleakage.Conclusions:Use of 1 mm of flowable composite intermediate layer improved the sealing ability of packable composites than the differential thickness of resin modified glass ionomer.

Evaluation of microleakage in posterior nanocomposite restorations with adhesive liners.

Aims and Objectives:To compare the microleakage in class II nanocomposite restorations without liner, with resin-modified glass ionomer liner and flowable composite liner.Materials and Methods:Thirty-six sound premolars extracted for orthodontic reasons were selected and randomly assigned into three groups of 12 teeth each (Group I, II and III). Class II cavities of specified dimensions were prepared with margins located in the enamel. Cavities in group I were lined with resin modified glass ionomer (GC Fuji II LC-Improved), group II were lined with flowable composite (Filtex Z350 Flowable Restorative) and no liner was placed for cavities in group III. All the teeth were restored with nanocomposite (Z 350 Universal Restorative). The teeth were immersed in 0.5% methylene blue dye, sectioned mesiodistally and observed under stereomicroscope.Results:Group III showed maximum leakage compared to group I and II which was statistically significant. Microleakage was lesser in group lined with resin-modified glass ionomer as compared to flowable composite group but not statistically significant.Conclusions:Placement of liner beneath nanocomposite restoration results in significant reduction in microleakage. Both resin-modified and flowable composite liners under nanocomposite restorations result in comparable reduction of microleakage.

Spatially resolved assessments of composite shrinkage in MOD restorations using a digital-image-correlation technique

Objectives To analyze the influence of cavity geometry and lining materials in MOD composite restorations by characterizing the polymerization shrinkage and cusp deflection. Methods Eighty intact molars with similar sizes were collected and randomly divided into eight groups. MOD cavities with various widths and depths were prepared on these teeth: Group I, 2 ( W) × 2 ( D) mm; Group II, 4 ( W) × 2 ( D) mm; Groups III, IIIf, IIIg, 2 ( W) × 4 ( D) mm; and Groups IV, IVf, IVg, 4 ( W) × 4 ( D) mm. In Groups IIIf and IVf, flowable composite liner was placed prior to composite restoration, while glass-ionomer liner was used in Groups IIIg and IVg. Deformations of restorations resulted from composite shrinkage were recorded for 30 min following light irradiation using a digital-image-correlation (DIC) method to subpixel level. The displacements at the boundaries of the restorations were analyzed using one-way ANOVA and the post hoc test at a 5% significance level. The correlation between the geometric factors and the displacements was also analyzed. Results The inward displacements on free surfaces were greater than those on the bonded surfaces. Groups with flowable composite linings showed greater amount of displacements on free and bonded surfaces compared to the unlined and glass ionomer lining groups. The correlation analysis showed that the free surface shrinkage was related with the cavity width and C-factor, while cusp deflections were correlated with the cavity depth and the cusp compliance. Significance The DIC technique measures composite shrinkage on different boundaries of restorations to facilitate the investigation of polymerization kinetics. Using flowable composite lining and increased cusp depth may aggravate the cusp flexure.

Effect of different placement techniques on marginal microleakage of deep class-II cavities restored with two composite resin formulations

Aim:The study aims to evaluate and compare marginal microleakage in deep class II cavities restored with various techniques using different composites.Materials and Methods:Sixty freshly extracted teeth were divided into six groups of 10 teeth each. Standardized class II cavities were made and were restored using composites of different consistencies with different placement techniques. Group 1 with Microhybrid composite, Group 2 with Packable composite, Group 3 Microhybrid composite with a flowable composite liner, Group 4 Packable composite with a flowable composite liner, Group 5 Microhybrid composite with precured composite insert in second increment and Group 6 Packable composite with precured insert in second increment. Specimens then were stored in distilled water, thermocycled and immersed in 50% silver nitrate solution. These specimens were sectioned and evaluated for microleakage at the occlusal and cervical walls separately using stereomicroscope.Results:The results demonstrated that in the occlusal wall, packable composite, showed significantly more marginal microleakage than the other groups. In the cervical wall, teeth restored with a flowable composite liner showed less marginal microleakage when compared to all other groups.Conclusion:Based on the results of this study, the use of flowable composite as the first increment is recommended in deep class II cavities.

Effect of Resin Liners and Photoactivation Methods on the Shrinkage Stress of a Resin Composite

This study was undertaken to evaluate the effect of three different photoactivation methods on the polymerization shrinkage stress of a resin composite using different resin liners. Three photoactivation methods using a quartz-tungsten-halogen light were evaluated: continuous light, soft start, and intermittent light. Three lining groups were tested: one or three coats of adhesive, and flowable composite. The stress was measured using a universal testing machine. After the stress measurement, Knoop hardness numbers (KHNs) were evaluated to verify indirectly the degree of conversion of the composite using the three photoactivation methods. The data were submitted to analysis of variance and Tukey's test (p < .05). Intermittent light was always associated with statistically lower stress values when compared with continuous light. Statistical differences were not observed when continuous light and soft start were compared. The use of a flowable composite liner significantly reduced the stress generation when compared with the use of one adhesive coat. The three adhesive coats groups showed intermediate stress values. The hardness test showed no statistical difference between that achieved with continuous light and soft start. These two methods showed statistically higher KHNs when compared with results with intermittent light. Photoactivation using intermittent light may lead to a significant reduction in shrinkage stress levels. This effect could be attributed to a significant reduction of the polymerization rate and/or a decrease in the degree of conversion. The use of a flowable composite liner reduced the stress levels when compared with levels when one coat of adhesive was used. This is possibly related to the higher thickness of the flowable composite layer.

In vivo interfacial adaptation of class II resin composite restorations with and without a flowable resin composite liner

The aim of this study was to evaluate in vivo the interfacial adaptation of class II resin composite restorations with and without a flowable liner. In 24 premolars scheduled to be extracted after 1 month, 48 box-shaped, enamel-bordered class II cavities were prepared and restored with a flowable liner (FRC, Tetric Flow/Tetric Ceram/Syntac Single-Component) or without (TRC), cured with three different curing modes: soft start and 500- or 700-mW/cm2 continuous irradiation. Interfacial adaptation was evaluated by quantitative scanning electron microscopic analysis using replica method. Gap-free adaptation in the cervical enamel (CE) was observed for FRC and TRC in 96.2 and 90.2%, for the dentin (D) in 63.6 and 64.9%, and for occlusal enamel (OE) in 99.7 and 99.5%, respectively. The difference between the two restorations was not statistically significant (ns). Significant better adaptation was observed for OE than CE and D (p<0.01), and for CE than D (p<0.01). Gap-free adaptation with the soft-start and 500- and 700-mW/cm2 continuous-curing modes was observed for CE: 88.7%, 92.7%, 97.9% (ns); OE: 99.8%, 98.7%, 100% (ns); and D: 64.0%, 63.9%, and 64.6% (ns), respectively. It can be concluded that neither the use of flowable resin composite liner nor the curing mode used influenced the interfacial adaptation.

Fracture resistance of class II packable composite restorations with and without flowable liners

This study evaluated fracture resistance in class II slot packable composite restorations with and without the use of a flowable composite liner. A conventional microhybrid composite was used as a control. Thirty-six sound, caries-free human mandibulary molar teeth were used. Separate mesio-occlusal and disto-occlusal class II slot cavity preparations were made in each tooth. The prepared teeth were randomly divided into three groups of 12 teeth. Two packable composites (Surefil, Filtek P60) and one microhybrid composite (Filtek Z250) with their respective manufacturer's bonding agents were used to restore the cavities. One side of each tooth was restored with composite alone, while the other side was restored with the composite lined with that manufacturer's flowable liner. The marginal ridges of the restorations were loaded at an angle of 13.5 degrees to the long-axis of the tooth in an Instron Testing Machine until failure. The data were analysed using a one-way anova. There was no significant difference in fracture resistance between composite restorations with and without flowable liners.