Effect of Simulated Pulpal Microcirculation on Temperature When Light Curing Bulk Fill Composites

2019 ◽  
Vol 44 (3) ◽  
pp. 289-301 ◽  
Author(s):  
SSL Braga ◽  
LRS Oliveira ◽  
MTH Ribeiro ◽  
ABF Vilela ◽  
GR da Silva ◽  
...  
Keyword(s):  
Temperature Rise ◽  
Light Transmission ◽  
Resin Composite ◽  
Exothermic Reaction ◽  
Adhesive System ◽  
Degree Of Conversion ◽  
Pulp Chamber ◽  
Significance Level ◽  
Light Curing ◽  
Lower Temperature

SUMMARY Objectives: To evaluate the effect of light curing bulk fill resin composite restorations on the increase in the temperature of the pulp chamber both with and without a simulated pulpal fluid flow. Methods and Materials: Forty extracted human molars received a flat occlusal cavity, leaving approximately 2 mm of dentin over the pulp. The teeth were restored using a self-etch adhesive system (Clearfil SE Bond, Kuraray) and two different bulk fill resin composites: a flowable (SDR, Dentsply) and a regular paste (AURA, SDI) bulk fill. The adhesive was light cured for 20 seconds, SDR was light cured for 20 seconds, and AURA was light cured for 40 seconds using the Bluephase G2 (Ivoclar Vivadent) or the VALO Cordless (Ultradent) in the standard output power mode. The degree of conversion (DC) at the top and bottom of the bulk fill resin composite was assessed using Fourier-Transform Infra Red spectroscopy. The temperature in the pulp chamber when light curing the adhesive system and resin composite was measured using a J-type thermocouple both with and without the presence of a simulated microcirculation of 1.0-1.4 mL/min. Data were analyzed using Student t-tests and two-way and three-way analyses of variance (α=0.05 significance level). Results: The irradiance delivered by the light-curing units (LCUs) was greatest close to the top sensor of the MARC resin calibrator (BlueLight Analytics) and lowest after passing through the 4.0 mm of resin composite plus 2.0 mm of dentin. In general, the Bluephase G2 delivered a higher irradiance than did the VALO Cordless. The resin composite, LCU, and region all influenced the degree of cure. The simulated pulpal microcirculation significantly reduced the temperature increase. The greatest temperature rise occurred when the adhesive system was light cured. The Bluephase G2 produced a rise of 6°C, and the VALO Cordless produced a lower temperature change (4°C) when light curing the adhesive system for 20 seconds without pulpal microcirculation. Light curing SDR produced the greatest exothermic reaction. Conclusions: Using simulated pulpal microcirculation resulted in lower temperature increases. The flowable composite (SDR) allowed more light transmission and had a higher degree of conversion than did the regular paste (AURA). The greatest temperature rise occurred when light curing the adhesive system alone.

Effect of Light Activation of Pulp-Capping Materials and Resin Composite on Dentin Deformation and the Pulp Temperature Change

2018 ◽  
Vol 43 (1) ◽  
pp. 71-80 ◽  
Author(s):  
CJ Soares ◽  
MS Ferreira ◽  
AA Bicalho ◽  
M de Paula Rodrigues ◽  
SSL Braga ◽  
...  
Keyword(s):  
Resin Composite ◽  
Glass Ionomer Cement ◽  
Adhesive System ◽  
Polymerization Temperature ◽  
Micro Ct ◽  
Light Activation ◽  
Pulp Chamber ◽  
Pulp Capping ◽  
Light Curing ◽  
Composite Restoration

SUMMARY Objectives: To analyze the effect of pulp-capping materials and resin composite light activation on strain and temperature development in the pulp and on the interfacial integrity at the pulpal floor/pulp-capping materials in large molar class II cavities. Methods: Forty extracted molars received large mesio-occlusal-distal (MOD) cavity bur preparation with 1.0 mm of dentin remaining at the pulp floor. Four pulp-capping materials (self-etching adhesive system, Clearfil SE Bond [CLE], Kuraray), two light-curing calcium hydroxide cements (BioCal [BIO], Biodinâmica, and Ultra-Blend Plus [ULT], Ultradent), and a resin-modified glass ionomer cement– (Vitrebond [VIT], 3M ESPE) were applied on the pulpal floor. The cavities were incrementally restored with resin composite (Filtek Z350 XT, 3M ESPE). Thermocouple (n=10) and strain gauge (n=10) were placed inside the pulp chamber in contact with the top of the pulpal floor to detect temperature changes and dentin strain during light curing of the pulp-capping materials and during resin composite restoration. Exotherm was calculated by subtracting postcure from polymerization temperature (n=10). Interface integrity at the pulpal floor was investigated using micro-CT (SkyScan 1272, Bruker). The degree of cure of capping materials was calculated using the Fourier transform infrared and attenuated total reflectance cell. Data were analyzed using one-way analysis of variance followed by the Tukey test (α=0.05). Results: Pulpal dentin strains (μs) during light curing of CLE were higher than for other pulp-capping materials (p<0.001). During resin composite light activation, the pulpal dentin strain increased for ULT, VIT, and CLE and decreased for BIO. The pulpal dentin strain was significantly higher during pulp-capping light activation. The temperature inside the pulp chamber increased approximately 3.5°C after light curing the pulp-capping materials and approximately 2.1°C after final restoration. Pulp-capping material type had no influence temperature increase. The micro-CT showed perfect interfacial integrity after restoration for CLE and ULT; however, gaps were found between BIO and pulpal floor in all specimens. BIO had a significantly lower degree of conversion than ULT, VIT, and CLE. Conclusions: Light curing of pulp-capping materials caused deformation of pulpal dentin and increased pulpal temperature in large MOD cavities. Shrinkage of the resin composite restoration caused debonding of BIO from the pulpal floor.

Degree of Conversion Contributes to Dentin Bonding Durability of Contemporary Universal Adhesives

2020 ◽  
Vol 45 (5) ◽  
pp. 556-566 ◽  
Author(s):  
A Tichy ◽  
K Hosaka ◽  
A Abdou ◽  
M Nakajima ◽  
J Tagami
Keyword(s):  
Bond Strength ◽  
Resin Composite ◽  
Degree Of Conversion ◽  
Significance Level ◽  
Dentin Bonding ◽  
Light Curing ◽  
Bonding Durability ◽  
Universal Adhesives ◽  
High Degree

Clinical Relevance The degree of conversion of contemporary universal adhesives positively correlates with the bond strength to dentin. The correlation is more marked after thermocycling, suggesting that a high degree of conversion is required for long-term dentin bonding durability. SUMMARY Purpose: The objectives of this study were to evaluate the micro-tensile bond strength (μTBS) of five contemporary universal adhesives to dentin after 24 hours and thermocycling (TC), to measure their degrees of conversion (DC) and to test the correlation between μTBS and DC. Methods and Materials: Four commercially available universal adhesives, Prime&Bond universal (PBU), Ecosite Bond (EB), G-Premio Bond (GPB), and Clearfil Universal Bond Quick (UBQ), and one experimental adhesive, UBQ without an amide monomer (UBQ-A), were used in this study. For the μTBS test, midcoronal dentin of 50 human molars was exposed, ground using 600-grit SiC paper, and the adhesives were applied according to the manufacturers’ instructions. After resin-composite buildup and 24-hour water storage, one-half of the specimens were subjected to 15,000 thermal cycles. The specimens were sectioned into beams and stressed in tension at a crosshead speed of 1 mm/min until failure. The DC of adhesives applied to dentin was evaluated using attenuated total reflectance Fourier-transform infrared spectroscopy immediately after light-curing. All data were statistically analyzed at a significance level of 0.05. Results: The highest μTBSs were obtained with UBQ, UBQ-A, and PBU, which were not significantly different from each other both after 24 hours and TC. The μTBS of GPB was lower compared with the aforementioned adhesives, but significantly only after TC, and the lowest μTBSs were obtained with EB. TC did not affect the μTBSs of UBQ, UBQ-A, and PBU significantly, but a significant decrease was observed with GPB and EB. The highest DC was obtained with PBU and UBQ, followed by 2-hydroxyethyl methacrylate–rich adhesives UBQ-A and EB, which exhibited significantly lower DCs. The DC of GPB could not be determined because the reference peak at 1608 cm−1 was not detected in its spectra. A significant positive correlation was shown between μTBS and DC after 24 hours (r=0.716) and TC (r=0.856). Conclusion: μTBS and DC were positively correlated, more markedly after TC, which suggests that DC may be an important factor for bond durability.

scholarly journals Impact of Material Shade and Distance from Light Curing Unit Tip on the Depth of Polymerization of Composites

2017 ◽  
Vol 28 (5) ◽  
pp. 632-637 ◽  
Author(s):  
André L. Faria-e-Silva ◽  
Christopher Fanger ◽  
Lillian Nguyen ◽  
Demetri Howerton ◽  
Carmem S. Pfeifer
Keyword(s):  
Light Transmission ◽  
Degree Of Conversion ◽  
Experimental Conditions ◽  
Composite Surface ◽  
Infra Red ◽  
Light Curing ◽  
Different Depths ◽  
The Mean

Abstract This study aimed to evaluate the effect of the composite shade and distance from the light-curing unit (LCU) tip on the irradiance reaching the bottom of composite disks and on the depth of polymerization. Composites of three shades (opaque - OXDC, bleach - BXL, and A2) were inserted into molds with 3-mm of thickness positioned over a spectrometer and photo-activated with the LCU (Bluephase) tip placed at 0 or 1 cm from the composite surface. The mean irradiance reaching the bottom of composite was recorded during the entire photo-activation (30 s). Specimens (2 x 2 x 4 mm) were polymerized and used to map the degree of conversion achieved in different depths from irradiated surface. Specimens were sectioned into slices that were positioned over the platform of the infra-red microscope connected to the spectrometer to map the conversion. The conversion was measured in eight different depths every 500-µm. Increasing the distance of LCU tip reduced the irradiance only for A2. Interposing OXDC disks resulted in lowest values of irradiance and A2 the highest one. A tendency to decrease the conversion was observed towards the bottom of specimens for all experimental conditions, and the slope was more accentuated for OXDC. Differences among shades and distances from LCU tip were evident only beyond 1.5-2.0 mm of depth. In conclusion, both composite shade and distance from LCU tip might affect the light-transmission and depth of polymerization, while the effect of last was more pronounced.

Comparison of Composite Curing Parameters: Effects of Light Source and Curing Mode on Conversion, Temperature Rise and Polymerization Shrinkage

10.2341/05-15 ◽  
2006 ◽  
Vol 31 (2) ◽  
pp. 219-226 ◽  
Author(s):  
Z. Tarle ◽  
A. Knezevic ◽  
N. Demoli ◽  
A. Meniga ◽  
J. Sutalo ◽  
...  
Keyword(s):  
Light Source ◽  
Temperature Rise ◽  
Thermal Injury ◽  
Resin Composite ◽  
Marginal Adaptation ◽  
Low Intensity ◽  
Halogen Light ◽  
Lower Temperature ◽  
Final Degree ◽  
Conversion Temperature

Clinical Relevance The use of a low intensity light source for photopolymerization based on LED technology provides equivalent final degree conversion with possible flow of the resin composite, similar to when QTH technology is used. At the same time, the lower temperature rise in the sample and the more favorable development of shrinkage kinetics compared to the higher intensities of halogen light may aid in maintaining marginal adaptation while avoiding possible thermal injury.

scholarly journals Effects of radiant exposure values using second and third generation light curing units on the degree of conversion of a lucirin-based resin composite

2017 ◽  
Vol 25 (2) ◽  
pp. 140-146 ◽  
Author(s):  
Kelly Antonieta Oliveira Rodrigues de Faria CARDOSO ◽  
Driellen Christine ZARPELLON ◽  
Camila Ferreira Leite MADRUGA ◽  
José Augusto RODRIGUES ◽  
Cesar Augusto Galvão ARRAIS
Keyword(s):  
Resin Composite ◽  
Degree Of Conversion ◽  
Third Generation ◽  
Radiant Exposure ◽  
Light Curing

scholarly journals Push-Out Bond Strength of Restorations with Bulk-Fill, Flow, and Conventional Resin Composites

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Rodrigo Vieira Caixeta ◽  
Ricardo Danil Guiraldo ◽  
Edmilson Nobumitu Kaneshima ◽  
Aline Silvestre Barbosa ◽  
Cassiana Pedrotti Picolotto ◽  
...  
Keyword(s):  
Bond Strength ◽  
Light Emitting Diode ◽  
Resin Composite ◽  
Testing Machine ◽  
Adhesive System ◽  
Optical Microscope ◽  
Resin Composites ◽  
Conical Cavity ◽  
Significance Level ◽  
Push Out

The aim of this study was to evaluate the bond strengths of composite restorations made with different filler amounts and resin composites that were photoactivated using a light-emitting diode (LED). Thirty bovine incisors were selected, and a conical cavity was prepared in the facial surface of each tooth. All preparations were etched with Scotchbond Etching Gel, the Adper Scotchbond Multipurpose Plus adhesive system was applied followed by photoactivation, and the cavities were filled with a single increment of Filtek Z350 XT, Filtek Z350 XT Flow, or bulk-fill X-tra fil resin composite (n= 10) followed by photoactivation. A push-out test to determine bond strength was conducted using a universal testing machine. Data (MPa) were submitted to Student’st-test at a 5% significance level. After the test, the fractured specimens were examined using an optical microscope under magnification (10x). Although all three composites demonstrated a high prevalence of adhesive failures, the bond strength values of the different resin composites photoactivated by LED showed that the X-tra fil resin composite had a lower bond strength than the Filtek Z350 XT and Filtek Z350 XT Flow resin composites.

scholarly journals Resin Bonding of Self-Etch Adhesives to Bovine Dentin Bleached from Pulp Chamber

2016 ◽  
Vol 2016 ◽  
pp. 1-7
Author(s):  
Akiko Haruyama ◽  
Atsushi Kameyama ◽  
Junji Kato ◽  
Shinji Takemoto ◽  
Yutaka Oda ◽  
...  
Keyword(s):  
Bond Strength ◽  
Resin Composite ◽  
Adhesive System ◽  
Unit Group ◽  
Tooth Bleaching ◽  
Pulp Chamber ◽  
Halogen Light ◽  
Group 2 ◽  
Self Etch ◽  
Group 1

This study evaluated the microtensile bond strength (μTBS) of 1-step self-etch adhesives (1-SEAs) and 2-step self-etch adhesives (2-SEAs) to pulp chamber dentin immediately after bleaching with 2 types of common bleaching techniques. Pulp chamber dentin of bovine teeth was bleached using 30% hydrogen peroxide (H2O2) solution with quartz-tungsten-halogen light-curing unit (Group 1) and 3.5% H2O2-containing titanium dioxide (TiO2) (Pyrenees®) activated with 405-nm violet diode laser for 15 min (Group 2). Unbleached specimens were placed in distilled water for 15 min and used as controls. After treatment, dentin was bonded with resin composite using 1-SEA or 2-SEA and stored in water at 37°C for 24 h. Each specimen was sectioned and trimmed to an hourglass-shape andμTBS was measured. Fractured specimens were examined under a scanning electron microscope to determine fracture modes. All specimens in Group 1 failed before proper bonding tests. In Group 2, theμTBS of 2-SEA was significantly greater (with no failed specimens) than 1-SEA (where 21 out of 36 failed). These results indicate that 2-SEA is a better adhesive system than 1-SEA on bleached dentin. Our results also demonstrated that application of H2O2significantly decreases bond strength of resin to dentin; however, in the case of nonvital tooth bleaching, Pyrenees® is a better alternative to the conventional 30% H2O2bleaching.

A Study of Temperature Rise in the Pulp Chamber during Composite Polymerization with Different Light-curing Units

2007 ◽  
Vol 8 (7) ◽  
pp. 29-37 ◽  
Author(s):  
Christopher Millen ◽  
Martyn Ormond ◽  
Gillian Richardson ◽  
Ario Santini ◽  
Vesna Miletic ◽  
...  
Keyword(s):  
Light Intensity ◽  
Temperature Rise ◽  
Bonding Agent ◽  
Pulp Chamber ◽  
Data Logger ◽  
Bonding Agents ◽  
Pulp Temperature ◽  
Light Curing ◽  
Temperature Records ◽  
Group 2

Abstract Aim The study compared pulp temperature rise during polymerization of resin-based composites (RBCs) using halogen and LED light-curing units (LCUs). Methods and Materials A total of 32 teeth extracted from patients aged 11-18 years were used in the study. Thermocouples placed on the roof of the pulp chamber using a novel ‘split-tooth’ method. In Group 1 a halogen LCU with a light intensity of 450 mWcm-2 was used and in Group 2, an LED LCU with a light intensity of 1100 mWcm-2 was used. The teeth were placed in a water bath with the temperature regulated until both the pulp temperature and the ambient temperature were stable at 37°C. Continuous temperature records were made via a data logger and computer. The increase in temperature from baseline to maximum was calculated for each specimen during the curing of both the bonding agent and the RBC. Results The rise in pulp temperature was significantly higher with the LED LCU than with the halogen LCU for bonding and RBC curing (p<0.05). The major rise in temperature occured during the curing of the bonding agent. During the curing of the RBC, rises were smaller. Conclusions Curing of bonding agents should be done with low intensity light and high intensity used only for curing RBC regardless of whether LED or halogen LCUs are used. Citation Millen C, Ormond M, Richardson G, Santini A, Miletic V, Kew P. A Study of Temperature Rise in the Pulp Chamber during Composite Polymerization with Different Light-curing Units. J Contemp Dent Pract 2007 November; (8)7:029-037.

Thermal Variations in the Pulp Chamber Associated with Composite Insertion Techniques and Light-curing Methods

2009 ◽  
Vol 10 (1) ◽  
pp. 17-24 ◽  
Author(s):  
Mário Alexandre Coelho Sinhoreti ◽  
Ricardo Danil Guiraldo ◽  
Simonides Consani ◽  
Lourenço Correr-Sobrinho ◽  
Luis Felipe Jochims Schneider
Keyword(s):  
Light Exposure ◽  
Resin Composite ◽  
Continuous Light ◽  
Pulp Chamber ◽  
Pulp Tissue ◽  
Soft Start ◽  
Halogen Light ◽  
Curing Methods ◽  
Light Curing ◽  
Insertion Techniques

Abstract Aim The aim of this study was to investigate the effect of different incremental insertion techniques, photoactivation, and restorative phases on thermal variations occurring during the polymerization of Filtek Z250 composite resin. Methods and Materials The experiment was conducted using 90 bovine incisor teeth. The teeth were randomly assigned to three groups according to the technique used for photoactivation with a halogen light (continuous, soft-start, or intermittent). The groups were further separated into three subgroups according to method of increment placement (bulk, oblique, or horizontal/vertical) for a total of nine groups (n=10). Restorations were placed in a controlled environment (37°C and 50±10% RU) and the temperature recorded using a digital thermometer coupled to a Type-K thermocouple inserted in the pulp chamber through the root canal in contact with the dentin. Data were analyzed using an analysis of variance (ANOVA) and the Tukey's test. Results Higher temperature values were found for continuous light photoactivation in combination with the placement of horizontal/vertical composite increments and photoactivation of the adhesive using a continuous light exposure. Conclusion The light source is the most important factor producing temperature changes during photoactivation of resin composite. Clinical Significance Temperature increases in the pulp chamber due to light curing should be considered to avoid harming the delicate pulp tissue when large restorations or inlays/onlays require several consecutive light curing exposures for a complete cure. Citation Guiraldo RD, Consani S, Sinhoreti MAC, Correr-Sobrinho L, Schneider LFJ. Thermal Variations in the Pulp Chamber Associated with Composite Insertion Techniques and Light-curing Methods. J Contemp Dent Pract 2009 January; (10)1:017-024.

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