scholarly journals Light induced polymerization of resin composite restorative materials

2004 ◽  
Vol 57 (11-12) ◽  
pp. 556-560
Author(s):  
Larisa Blazic ◽  
Dubravka Markovic ◽  
Milanko Djuric
Keyword(s):  
Stress Reduction ◽  
Resin Composite ◽  
Dental Materials ◽  
Adhesive Bond ◽  
Adhesive System ◽  
Filler Loading ◽  
Polymerization Reaction ◽  
Shrinkage Stress ◽  
Polymerization Shrinkage ◽  
Dental Resins

Introduction Dimensional stability of polymer-based dental materials is compromised by polymerization reaction of the monomer. The conversion into a polymer is accompanied by a closer packing of molecules, which leads to volume reduction called curing contraction or polymerization shrinkage. Curing contraction may break the adhesion between the adhesive system and hard tooth tissues forming micrographs which may result in marginal deterioration, recurrent caries and pulp injury. Polymerization shrinkage of resin-based restorative dental materials Polymerization of the organic phase (monomer molecules) of resin-based dental materials causes shrinkage. The space occupied by filler particles is not associated with polymerization shrinkage. However, high filler loading within certain limits, can contribute to a lesser curing contraction. Polymerization shrinkage stress and stress reduction possibilities Polymerization shrinkage stress of polymer-based dental resins can be controlled in various ways. The adhesive bond in tooth-restoration interface guides the contraction forces to cavity walls. If leakage occurs, complications like secondary caries and pulpal irritation may jeopardize the longevity of a restoration. Stress relieve can be obtained by modifications of the monomer and photoinitiator, or by specially designed tooth preparation and application of bases and liners of low modulus of elasticity. The polymerization contraction can be compensated by water absorption due to oral cavity surrounding. The newest approach to stress relief is based on modulation of polymerization initiation. Conclusion This work deals with polymerization contraction and how to achieve leak-proof restoration. Restorative techniques that may reduce the negative effect of polymerization shrinkage stress need further research in order to confirm up-to-date findings.

Polymerization shrinkage stress of resin-based dental materials: A systematic review and meta-analyses of composition strategies

2018 ◽  
Vol 82 ◽  
pp. 268-281 ◽  
Author(s):  
Carine Tais Welter Meereis ◽  
Eliseu Aldrighi Münchow ◽  
Wellington Luiz de Oliveira da Rosa ◽  
Adriana Fernandes da Silva ◽  
Evandro Piva
Keyword(s):  
Systematic Review ◽  
Dental Materials ◽  
Shrinkage Stress ◽  
Polymerization Shrinkage ◽  
Meta Analyses

Relationship Between Shrinkage and Stress

2011 ◽  
pp. 1374-1392
Author(s):  
Antheunis Versluis ◽  
Daranee Tantbirojn
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Clinical Symptoms ◽  
Dental Materials ◽  
Vital Role ◽  
Controlling Factors ◽  
Shrinkage Stress ◽  
Polymerization Shrinkage ◽  
Multiple Factors ◽  
Restorative Dental Materials

Residual stress due to polymerization shrinkage of restorative dental materials has been associated with a number of clinical symptoms, ranging from post-operative sensitivity to secondary caries to fracture. Although the concept of shrinkage stress is intuitive, its assessment is complex. Shrinkage stress is the outcome of multiple factors. To study how they interact requires an integrating model. Finite element models have been invaluable for shrinkage stress research because they provide an integration environment to study shrinkage concepts. By retracing the advancements in shrinkage stress concepts, this chapter illustrates the vital role that finite element modeling plays in evaluating the essence of shrinkage stress and its controlling factors. The shrinkage concepts discussed in this chapter will improve clinical understanding for management of shrinkage stress, and help design and assess polymerization shrinkage research.

Polymerization shrinkage stress of resin-based dental materials: A systematic review and meta-analyses of technique protocol and photo-activation strategies

2018 ◽  
Vol 82 ◽  
pp. 77-86 ◽  
Author(s):  
Eliseu Aldrighi Münchow ◽  
Carine Tais Welter Meereis ◽  
Wellington Luiz de Oliveira da Rosa ◽  
Adriana Fernandes da Silva ◽  
Evandro Piva
Keyword(s):  
Systematic Review ◽  
Dental Materials ◽  
Shrinkage Stress ◽  
Polymerization Shrinkage ◽  
Meta Analyses

scholarly journals Polymerization shrinkage stress of composites photoactivated by different light sources

2009 ◽  
Vol 20 (4) ◽  
pp. 319-324 ◽  
Author(s):  
Fernanda de Carvalho Panzeri Pires de Souza ◽  
Brahim Drubi Filho ◽  
Luciana Assirati Casemiro ◽  
Lucas da Fonseca Roberti Garcia ◽  
Simonides Consani
Keyword(s):  
Light Emitting Diode ◽  
Testing Machine ◽  
Adhesive System ◽  
Composite Resins ◽  
Shrinkage Stress ◽  
Light Sources ◽  
Polymerization Shrinkage ◽  
Light Emitting ◽  
Halogen Light ◽  
Glass Rods

The purpose of this study was to compare the polymerization shrinkage stress of composite resins (microfilled, microhybrid and hybrid) photoactivated by quartz-tungsten halogen light (QTH) and light-emitting diode (LED). Glass rods (5.0 mm x 5.0 cm) were fabricated and had one of the surfaces air-abraded with aluminum oxide and coated with a layer of an adhesive system, which was photoactivated with the QTH unit. The glass rods were vertically assembled, in pairs, to a universal testing machine and the composites were applied to the lower rod. The upper rod was placed closer, at 2 mm, and an extensometer was attached to the rods. The 20 composites were polymerized by either QTH (n=10) or LED (n=10) curing units. Polymerization was carried out using 2 devices positioned in opposite sides, which were simultaneously activated for 40 s. Shrinkage stress was analyzed twice: shortly after polymerization (t40s) and 10 min later (t10min). Data were analyzed statistically by 2-way ANOVA and Tukey's test (a=5%). The shrinkage stress for all composites was higher at t10min than at t40s, regardless of the activation source. Microfilled composite resins showed lower shrinkage stress values compared to the other composite resins. For the hybrid and microhybrid composite resins, the light source had no influence on the shrinkage stress, except for microfilled composite at t10min. It may be concluded that the composition of composite resins is the factor with the strongest influence on shrinkage stress.

Adhesive Bond Strengths Using Self- and Light-Cured Composites

2009 ◽  
Vol 10 (6) ◽  
pp. 25-32 ◽  
Author(s):  
Ricardo Walter ◽  
Georgia V. Macedo ◽  
Gustavo M. S. Oliveira ◽  
Edward J. Swift
Keyword(s):  
Resin Composite ◽  
Adhesive Bond ◽  
Adhesive System ◽  
Resin Composites ◽  
Microtensile Bond Strength ◽  
Microtensile Testing ◽  
Etch And Rinse ◽  
Occlusal Surfaces ◽  
One Step ◽  
Bond Strengths

Abstract Aim To evaluate the microtensile bond strength (μTBS) of four adhesive systems to dentin, using self- and light-cured resin composites. Methods and Materials Crowns of human molars were separated from the roots, and the occlusal surfaces were ground to obtain flat superficial dentin. Three etch-and-rinse adhesives—All-Bond 2, One-Step Plus, and OptiBond Solo Plus—and one self-etching primer system, Peak SE, were evaluated. Each adhesive group was divided into two subgroups according to the type of resin composite used. A self-cured (Bisfil 2B) or light-cured (Filtek Supreme Plus) resin composite build-up was incrementally inserted to the dentin after each adhesive system was applied. The bonded specimens were stored in water for 24 h and sectioned into beams. Microtensile testing was done, and the data were subjected to ANOVA and Fisher's PLSD test. Results The μTBS of All-Bond 2 and One- Step Plus was not affected by the type of resin composite used (p=0.3131 and p=0.1562, respectively). The μTBS of OptiBond Solo Plus was significantly reduced when used with selfcured resin composite (p<0.0001). Peak SE formed no bond of self-cured resin composite to dentin. Conclusions Some adhesives do not effectively bond self-cured resin composite to dentin. Clinical Significance Incompatibility between adhesives with low pH and certain self-cured resin composites can cause clinical debonding of restorations. Citation Walter R, Macedo GV, Oliveira GMS, Swift Jr EJ. Adhesive Bond Strengths Using Self- and Light-Cured Composites. J Contemp Dent Pract [Internet]. 2009 Nov; 10(6):025-032. Available from: http://www.thejcdp.com/journal/ view/volume10-issue6-walter.

Microcomputed Tomography Evaluation of Polymerization Shrinkage of Class I Flowable Resin Composite Restorations

2017 ◽  
Vol 42 (1) ◽  
pp. E16-E23 ◽  
Author(s):  
CS Sampaio ◽  
K-J Chiu ◽  
E Farrokhmanesh ◽  
M Janal ◽  
RM Puppin-Rontani ◽  
...  
Keyword(s):  
Resin Composite ◽  
Three Dimensional ◽  
Adhesive System ◽  
Microcomputed Tomography ◽  
Occlusal Surface ◽  
Class I ◽  
Polymerization Shrinkage ◽  
Significant Difference ◽  
Group 2 ◽  
Post Hoc

SUMMARY The present study aimed to characterize the pattern and volume of polymerization shrinkage of flowable resin composites, including one conventional, two bulk fill, and one self-adhesive. Standardized class I preparations (2.5 mm depth × 4 mm length × 4 mm wide) were performed in 24 caries-free human third molars that were randomly divided in four groups, according to the resin composite and adhesive system used: group 1 = Permaflo + Peak Universal Bond (PP); group 2 = Filtek Bulk Fill + Scotchbond Universal (FS); group 3 = Surefil SDR + XP Bond (SX); and group 4 = Vertise flow self-adhering (VE) (n=6). Each tooth was scanned three times using a microcomputed tomography (μCT) apparatus. The first scan was done after the cavity preparation, the second after cavity filling with the flowable resin composite before curing, and the third after it was cured. The μCT images were imported into three-dimensional rendering software, and volumetric polymerization shrinkage percentage was calculated for each sample. Data were submitted to one-way analysis of variance and post hoc comparisons. No significant difference was observed among PP, FS, and VE. SX bulk fill resin composite presented the lowest values of volumetric shrinkage. Shrinkage was mostly observed along the occlusal surface and part of the pulpal floor. In conclusion, polymerization shrinkage outcomes in a 2.5-mm deep class I cavity were material dependent, although most materials did not differ. The location of shrinkage was mainly at the occlusal surface.

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

Relationship Between Shrinkage and Stress

2010 ◽  
pp. 45-64 ◽  
Author(s):  
Antheunis Versluis ◽  
Daranee Tantbirojn
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Clinical Symptoms ◽  
Dental Materials ◽  
Vital Role ◽  
Controlling Factors ◽  
Shrinkage Stress ◽  
Polymerization Shrinkage ◽  
Multiple Factors ◽  
Restorative Dental Materials

Residual stress due to polymerization shrinkage of restorative dental materials has been associated with a number of clinical symptoms, ranging from post-operative sensitivity to secondary caries to fracture. Although the concept of shrinkage stress is intuitive, its assessment is complex. Shrinkage stress is the outcome of multiple factors. To study how they interact requires an integrating model. Finite element models have been invaluable for shrinkage stress research because they provide an integration environment to study shrinkage concepts. By retracing the advancements in shrinkage stress concepts, this chapter illustrates the vital role that finite element modeling plays in evaluating the essence of shrinkage stress and its controlling factors. The shrinkage concepts discussed in this chapter will improve clinical understanding for management of shrinkage stress, and help design and assess polymerization shrinkage research.

Measurement of the Internal Adaptation of Resin Composites Using Micro-CT and Its Correlation With Polymerization Shrinkage

2014 ◽  
Vol 39 (2) ◽  
pp. e57-e70 ◽  
Author(s):  
HJ Kim ◽  
SH Park
Keyword(s):  
Silver Nitrate ◽  
Resin Composite ◽  
Shrinkage Strain ◽  
Shrinkage Stress ◽  
Micro Ct ◽  
Thermomechanical Loading ◽  
Polymerization Shrinkage ◽  
Before And After ◽  
Strain Stress ◽  
Internal Adaptation

SUMMARY In the present study, the internal adaptation of dentin-composite interfaces with various resin composite materials under conditions of thermomechanical loading was analyzed nondestructively using micro–computed tomography (micro-CT), and these results were compared with analyses of microgaps after sectioning. Additionally, the correlation of internal adaptation with polymerization shrinkage strain and stress was evaluated. Four nonflowable resins, Gradia Direct (GD), Filtek P90 (P9), Filtek Z350 (Z3), and Charisma (CH), and two flowable resins, SDR (SD) and Tetric N-Flow (TF) were used. First, the polymerization shrinkage strain and stress were measured. Then, Class I cavities were prepared in 48 premolars. They were divided randomly into six groups, and the cavities were filled with composites using XP bond. To evaluate the internal adaptation, tooth specimens were immersed in a 25% silver nitrate solution, and micro-CT analysis was performed before and after thermomechanical loading. The silver nitrate penetration (%SP) was measured. After buccolingual sectioning and rhodamine penetration of the specimen, the rhodamine penetration (%RP) was measured using a stereo-microscope. One-way analysis of variance was then used to compare the polymerization shrinkage strain, stress, %SP, and %RP among the groups at a 95% confidence level. A paired t-test was used to compare the %SP before and after thermomechanical loading. Pearson correlation analysis was used to compare the correlation between polymerization shrinkage strain/stress and %SP or %RP to a 95% confidence level. Evaluation of the polymerization shrinkage strain demonstrated that P9 &lt; Z3 ≤ GD &lt; CH ≤ SD &lt; TF (p&lt;0.05); similarly, evaluation of the polymerization shrinkage stress showed that P9 ≤ GD ≤ Z3 ≤ CH ≤ SD &lt; TF (p&lt;0.05). The %SP showed that P9 ≤ GD ≤ Z3 &lt; CH ≤ SD &lt; TF (p&lt;0.05) before loading and that P9 ≤ GD ≤ Z3 ≤ CH ≤ SD &lt; TF (p&lt;0.05) after loading. There was a significant difference between the before-loading and after-loading measurements in all groups (p&lt;0.05). Additionally, there was a positive correlation between the %SP and the %RP (r=0.810, p&lt;0.001). Conclusively, the polymerization shrinkage stress and strain were found to be closely related to the internal adaptation of the resin composite restorations. The newly proposed model for the evaluation of internal adaptation using micro-CT and silver nitrate may provide a new measurement for evaluating the internal adaptation of restorations in a nondestructive way.

scholarly journals Effects of ionizing radiation on surface properties of current restorative dental materials

2021 ◽  
Vol 32 (6) ◽  
Author(s):  
Débora Michelle Gonçalves de Amorim ◽  
Aretha Heitor Veríssimo ◽  
Anne Kaline Claudino Ribeiro ◽  
Rodrigo Othávio de Assunção e Souza ◽  
Isauremi Vieira de Assunção ◽  
...  
Keyword(s):  
Ionizing Radiation ◽  
Surface Properties ◽  
Resin Composite ◽  
Dental Materials ◽  
Glass Ionomer Cement ◽  
Contact Angles ◽  
Glass Ionomer ◽  
Post Radiation ◽  
Restorative Dental Materials ◽  
Ionomer Cement

AbstractTo investigate the impact of radiotherapy on surface properties of restorative dental materials. A conventional resin composite—CRC (Aura Enamel), a bulk-fill resin composite—BFRC (Aura Bulk-fill), a conventional glass ionomer cement—CGIC (Riva self cure), and a resin-modified glass ionomer cement—RMGIC (Riva light cure) were tested. Forty disc-shaped samples from each material (8 mm diameter × 2 mm thickness) (n = 10) were produced according to manufacturer directions and then stored in water distilled for 24 h. Surface wettability (water contact angle), Vickers microhardness, and micromorphology through scanning electron microscopy (SEM) before and after exposition to ionizing radiation (60 Gy) were obtained. The data were statistically evaluated using the two-way ANOVA and Tukey posthoc test (p < 0.05). Baseline and post-radiation values of contact angles were statistically similar for CRC, BFRC, and RMGIC, whilst post-radiation values of contact angles were statistically lower than baseline ones for CGIC. Exposition to ionizing radiation statistically increased the microhardness of CRC, and statistically decreased the microhardness of CGIC. The surface micromorphology of all materials was changed post-radiation. Exposure to ionizing radiation negatively affected the conventional glass ionomer tested, while did not alter or improved surface properties testing of the resin composites and the resin-modified glass ionomer cement tested.

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