Influence of the Compliance and Layering Method on the Wall Deflection of Simulated Cavities in Bulk-fill Composite Restoration

2016 ◽  
Vol 41 (6) ◽  
pp. e183-e194 ◽  
Author(s):  
Y-J Kim ◽  
R Kim ◽  
JL Ferracane ◽  
I-B Lee
Keyword(s):  
Wall Thickness ◽  
Mold Wall ◽  
Flexural Modulus ◽  
The Other ◽  
Shrinkage Stress ◽  
Linear Variable Differential Transformer ◽  
Polymerization Shrinkage ◽  
Wall Deflection ◽  
Composite Restorations ◽  
Composite Restoration

SUMMARY The aim of this study was to investigate the effects of the layering method and compliance on the wall deflection of simulated cavities in bulk-fill and conventional composite restorations and to examine the relationships between the wall deflection and the polymerization shrinkage, flexural modulus, and polymerization shrinkage stress of composites. Six light-cured composites were used in this study. Two of these were conventional methacrylate-based composites (Filtek Z250 and Filtek Z350 XT Flowable [Z350F]), whereas four were bulk-fill composites (SonicFill, Tetric N-Ceram Bulk-Fill, SureFil SDR Flow [SDR], and Filtek Bulk-Fill). One hundred eighty aluminum molds simulating a mesio-occluso-distal cavity (6 W×8 L×4 D mm) were prepared and classified into three groups with mold wall thicknesses of 1, 2, and 3 mm. Each group was further subdivided according to the composite layering method (bulk or incremental layering). Linear variable differential transformer probes were used to measure the mold wall deflection of each composite (n=5) over a period of 2000 seconds (33.3 minutes). The polymerization shrinkage, flexural modulus, and polymerization shrinkage stress of the six composites were also measured. All groups with bulk filling exhibited significantly higher deflection compared with groups with incremental layering. The deflection decreased as mold wall thickness increased. The highest and lowest polymerization shrinkage stresses were recorded for Z350F (5.07 MPa) and SDR (1.70 MPa), respectively. The correlation between polymerization shrinkage and the mold wall deflection decreased with increasing wall thickness. On the other hand, the correlation between flexural modulus and the mold wall deflection increased with increasing wall thickness. For all groups, wall deflection correlated strongly with polymerization shrinkage stress.

Comparison of Internal Adaptation in Class II Bulk-fill Composite Restorations Using Micro-CT

2017 ◽  
Vol 42 (2) ◽  
pp. 203-214 ◽  
Author(s):  
SH Han ◽  
SH Park
Keyword(s):  
Class Ii ◽  
Ct Images ◽  
Shrinkage Stress ◽  
Micro Ct ◽  
Polymerization Shrinkage ◽  
Composite Restorations ◽  
Group 3 ◽  
Internal Adaptation ◽  
Group 5 ◽  
Group 2

SUMMARY Purpose: This study compared the internal adaptation of bulk-fill composite restorations in class II cavities and explored the relationship between internal adaptation and polymerization shrinkage or stress. Methods and Materials: Standardized mesio-occluso-distal cavities were prepared in 40 extracted human third molars and randomly divided into five groups (n=8). After having been applied by total-etch XP bond (Dentsply Caulk, Milford, DE, USA) and light curing, the teeth were restored with the following resin composites: group 1, Filtek Z350 (3M ESPE, St. Paul, MN, USA); group 2, SDR (Dentsply Caulk, Milford, DE, USA) + Z350; group 3, Venus Bulk Fill (Heraeus Kulzer, Dormagen, Germany) + Z350; group 4, Tetric N-Ceram Bulk Fill (Ivoclar Vivadent, Schaan, Liechtenstein); and group 5, SonicFill (Kerr, West Collins, Orange, CA, USA). After thermo-mechanical load cycling, cross-sectional microcomputerized tomography (micro-CT) images were taken. Internal adaptation was measured as imperfect margin percentage (IM%), which was the percentage of defective margin length relative to whole margin length. On the micro-CT images, IM% was measured at five interfaces. Linear polymerization shrinkage (LS) and polymerization shrinkage stress (PS) were measured on each composite with a custom linometer and universal testing machine. To explore the correlation of IM% and LS or PS, the Pearson correlation test was used. Results: The IM% of the gingival and pulpal cavity floors were inferior to those of the cavity walls. The IM% values of the groups were found to be as follows: group 5 ≤ groups 1 and 4 ≤ group 2 ≤ group 3. The correlation analysis showed that the p value was 0.006 between LS and IM% and 0.003 between PS and IM%, indicating significant correlations (p<0.05). Conclusion: Flowable bulk-fill composites had a higher IM% and polymerization shrinkage stress than did packable bulk-fill and hybrid composites. In class II composite restoration, the gingival floor of the proximal box and pulpal floor of the cavity had higher IM% than did the buccal and lingual walls of the proximal box. LS and PS, which were measured under compliance-allowed conditions, were significantly related to internal adaptation.

scholarly journals Reducing composite restoration polymerization shrinkage stress through resin modified glass-ionomer based adhesives

2015 ◽  
Vol 60 (4) ◽  
pp. 490-496 ◽  
Author(s):  
SJ Naoum ◽  
PR Mutzelburg ◽  
TG Shumack ◽  
DJG Thode ◽  
FE Martin ◽  
...  
Keyword(s):  
Shrinkage Stress ◽  
Glass Ionomer ◽  
Polymerization Shrinkage ◽  
Resin Modified Glass Ionomer ◽  
Composite Restoration

scholarly journals Formation of Diagonal Gaps as Stress-Relieving Sites: Rethinking the Concept of Increment Splitting in Direct Occlusal Composite Restorations

2021 ◽  
Vol 1 (1) ◽  
pp. 1-7
Author(s):  
Khamis A Hassan
Keyword(s):  
Stress Reduction ◽  
Three Dimensional ◽  
Current Paper ◽  
Shrinkage Stress ◽  
Polymerization Shrinkage ◽  
Composite Restorations ◽  
Stress Relieving ◽  
Light Curing ◽  
As Stress ◽  
Vertical Gap

The split-increment horizontal placement technique is currently used, along with other restorative techniques, in moderate-to-large occlusal cavities for reducing the shrinkage stress generated during light polymerization. Such stress, if released uncontrolled, may cause damage within the composite, tooth or at the adhesive interface. The term “diagonal cut” was used in our original paper published in 2005 to refer to the action of dividing each composite increment into segments prior to light polymerization and was presented in two-dimensional illustration. Besides, we made no mention in the original paper of the term “diagonal gap” as an outcome of such diagonal cutting. We currently recognize the importance of introducing the “diagonal gap” term and the need for shedding some light on its role to help provide a more comprehensive view of the split-increment technique. The purpose of the current paper is to rethink our increment splitting concept used in direct occlusal composite restorations by introducing the term “diagonal gap” as a stress-relieving vertical site and demonstrating it in a three-dimensional illustration for providing a more comprehensive understanding of the split-increment technique. Conclusion: In the current paper, the term “diagonal gap” is introduced to refer to the vertical gap created by diagonal cutting of the horizontal composite increment, before light curing. This gap enables the segmented composite increment to undergo unrestrained shrinkage, where each segment being free from adhesion at the gap site can deform independently from the other segments. The relief of the polymerization shrinkage stress generated during light curing prevents formation of cracks in enamel and/or composite, and debonding of adhesive interfaces. Keywords: deformation; diagonal gap; incremental; occlusal; polymerization shrinkage; posterior composite; segment; split-increment; stress reduction; stress-relieving site

The Combination of CQ-amine and TPO Increases the Polymerization Shrinkage Stress and Does Not Improve the Depth of Cure of Bulk-fill Composites

2019 ◽  
Vol 44 (5) ◽  
pp. 499-509
Author(s):  
MG Rocha ◽  
DCRS de Oliveira ◽  
MAC Sinhoreti ◽  
JF Roulet ◽  
AB Correr
Keyword(s):  
Near Infrared ◽  
Light Emitting Diode ◽  
Flexural Modulus ◽  
Degree Of Conversion ◽  
Light Transmittance ◽  
Volumetric Shrinkage ◽  
Shrinkage Stress ◽  
Polymerization Shrinkage ◽  
Depth Of Cure ◽  
Three Point Bend Test

SUMMARY Objectives: To evaluate the effect of combining camphorquinone (CQ) and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) on the depth of cure and polymerization shrinkage stress of bulk-fill composites. Methods and Materials: Experimental bulk-fill composites were produced containing equal molar concentrations of either CQ-amine or CQ-amine/TPO. The degree of in-depth conversion through each millimeter of a 4-mm-thick bulk-fill increment was evaluated by Fourier transform near-infrared microspectroscopy using a central longitudinal cross section of the increment of each bulk-fill composite (n=3). Light-transmittance of the multi-wave light-emitting diode (LED) emittance used for photoactivation (Bluephase G2, Ivoclar Vivadent) was recorded through every millimeter of each bulk-fill composite using spectrophotometry. The volumetric shrinkage and polymerization shrinkage stress were assessed using a mercury dilatometer and the Bioman, respectively. The flexural modulus was also assessed by a three-point bend test as a complementary test. Data were analyzed according to the different experimental designs (α=0.05 and β=0.2). Results: Up to 1 mm in depth, adding TPO to CQ-based bulk-fill composites increased the degree of conversion, but beyond 1 mm no differences were found. The light-transmittance of either wavelengths emitted from the multi-wave LED (blue or violet) through the bulk-fill composites were only different up to 1 mm in depth, regardless of the photoinitiator system. Adding TPO to CQ-based bulk-fill composites did not affect volumetric shrinkage but did increase the flexural modulus and polymerization shrinkage stress. Conclusion: Adding TPO to CQ-based bulk-fill composites did not increase the depth of cure. However, it did increase the degree of conversion on the top of the restoration, increasing the polymerization shrinkage stress.

scholarly journals Comparison of Proximal Contacts of Class II Resin Composite Restorations In Vitro

2006 ◽  
Vol 31 (6) ◽  
pp. 688-693 ◽  
Author(s):  
B. A. C. Loomans ◽  
N. J. M. Opdam ◽  
F. J. M. Roeters ◽  
E. M. Bronkhorst ◽  
R. C. W. Burgersdijk
Keyword(s):  
Clinical Relevance ◽  
Resin Composite ◽  
Class Ii ◽  
Composite Restorations ◽  
Composite Restoration

Clinical Relevance When placing a Class II resin composite restoration, the use of sectional matrix systems and separation rings to obtain tight proximal contacts is recommended.

scholarly journals Photoelastic evaluation of the effect of composite formulation on polymerization shrinkage stress

2012 ◽  
Vol 26 (3) ◽  
pp. 202-208 ◽  
Author(s):  
Karla Mychellyne Costa Oliveira ◽  
Simonides Consani ◽  
Luciano Souza Gonçalves ◽  
William Cunha Brandt ◽  
Renzo Alberto Ccahuana-Vásquez
Keyword(s):  
Shrinkage Stress ◽  
Polymerization Shrinkage

scholarly journals THE COMPARISON OF RESIN-BASED COMPOSITES PHYSICAL PROPERTIES BETWEEN BULK-FILL TECHNIQUE AND INCREMENTAL TECHNIQUE

2021 ◽  
Vol 6 (1) ◽  
pp. 85
Author(s):  
Rahmi Khairani Aulia
Keyword(s):  
Physical Properties ◽  
Composite Resin ◽  
Color Stability ◽  
Composite Resins ◽  
Shrinkage Stress ◽  
Restorative Material ◽  
Polymerization Shrinkage ◽  
Advantages And Disadvantages ◽  
Restoration Technique ◽  
Restoration Failure

ABSTRACT:Composite resins are currently the most popular restorative material in dentistry. This is due to good aesthetics and maximum conservation ability. Behind these advantages, there are disbenefits of composite resin materials, such as polymerization shrinkage, which can lead to restoration failure. Various attempts have been investigated to reduce the shrinkage incidence of composite resins, one of which is the technique of placing the restorative material into the cavity. The restoration filling technique is recognized as a significant factor in shrinkage stress. By using a special filling technique, the polymerization shrinkage damage stress can be reduced. There are several techniques in performing composite resin fillings, including bulk and incremental techniques. These techniques have their respective advantages and disadvantages. The aim of this literature review was to compare the physical properties of composite resin restorations with bulk filling and incremental techniques. Physical properties that being studied include polymerization shrinkage, stress shrinkage, degree of conversion, bonding strength, water resorption, color stability, and temperature increase. Comparing the two techniques, composite resin with incremental filling technique has superior physical properties compared to bulk technique. From the comparison of the two techniques, the composite resin with incremental filling technique has superior physical properties compared to the bulk technique, especially in higher conversion which causes lower shrinkage stress. This situation makes the incremental technique provide better bond strength, water resorption, color stability, and lower temperature rise.Keywords: Bulk, Composite Resin, Incremental,  Physical Properties, Restoration, Restoration Technique

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