scholarly journals Polywave And Monowave Light-Curing Units Effects On Polymerization Efficiency Of Different Photoinitiators

2021 ◽  
Vol 24 (4) ◽  
Author(s):  
Peterson Oliveira Boeira ◽  
Mateus De Azevedo Kinalski ◽  
Mateus Bertolini Fernandes dos Santos ◽  
Rafael Ratto de Moraes ◽  
Giana Silveira Lima
Keyword(s):  
Phosphine Oxide ◽  
Second Generation ◽  
Degree Of Conversion ◽  
Polymerization Reaction ◽  
Third Generation ◽  
Test Results ◽  
Vis Spectroscopy ◽  
Light Curing ◽  
Post Hoc ◽  
High Degree

Objective: of this study was to characterize and correlate the absorption spectra of three photoinitiators [camphorquinone (CQ), diphenyl(2,4,6-trimethylbenzoyl) phosphine oxide (TPO) and phenylbis (2,4,6-trimethylbenzoyl)-phosphine oxide (BAPO)], using second or third-generation light curing units (LCU), and to evaluate the degree of conversion and the physical properties of an experimental resin adhesive.  Material and methods: Second-generation (Radii-cal® and Emitter D®) and third-generation (Valo® Cordless and Bluephase N®) LCU were assessed regarding spectrum and irradiance rate of emitted light. Also, the photoinitiators (CQ, TPO and BAPO) were characterized by a light absorption spectrum assessed by UV-Vis spectroscopy, degree of conversion and yellowing effect. Statistical analyzes considered two-way ANOVA and post-hoc Tukey test.  Results: BAPO presented higher reactivity compared to TPO. Regarding degree of conversion of the photoinitiators activated by different light-curing units, the Emitter D® device promoted a high degree of conversion. BAPO presented the highest yellowing effect values. Conclusions: The emission and absorption characteristics of the photoinitiators were different. The polymerization reaction activated by the second-generation light-curing unit was reduced when using an experimental resin with photoinitiator TPO, and the third-generation light-curing unit showed a higher polymerization potential regardless of the photoinitiator. Keywords Light-curing of dental adhesives;  Photoinitiators dental; Curing lights dental.

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 Comparison of two curing protocols during adhesive cementation: can the step luting technique supersede the traditional one?

Odontology ◽  
2020 ◽  
Author(s):  
Vincenzo Tosco ◽  
Riccardo Monterubbianesi ◽  
Giulia Orilisi ◽  
Simona Sabbatini ◽  
Carla Conti ◽  
...  
Keyword(s):  
Degree Of Conversion ◽  
Third Generation ◽  
Luting Agents ◽  
Light Curing ◽  
Adhesive Cementation ◽  
Removal Of Cement ◽  
Time Point

Abstract This study aims to compare the degree of conversion of two different curing protocols used during adhesive cementation. The following resin luting agents were tested: Hri Flow (MF) and pre-heated Hri Micerium (MH); light-cure Nexus Third Generation (NX3L) and dual-cure Nexus Third Generation (NX3D); dual cured RelyX Ultimate (RXU) and light-cure RelyX Veneers (RXL). For each tested material, ten samples were prepared and divided into two groups which had different curing protocols (P1 and P2): in P1, samples were cured for 40 s; in P2, samples were cured for 5 s, and then, after 20 s, cured again for additional 40 s. The degree of conversion (DC) was evaluated both during the first 5 min of the curing phase and after 1, 2, 7, 14 and 28 days (p = 0.05). Different trends were observed in DC values after 5 min by comparing P1 and P2. In both P1 and P2, DC decreased as follows, MH > MF > NX3L > RXL > RXU > NX3D. There were significant differences of DC values among all resin luting agents (p < 0.05) in P1, while no significant differences existed between MH and MF, and NX3L and RXL in P2. At 1, 2, 7, 14 and 28 days the light curing luting agents had a higher DC than the dual luting agents (p < 0.05). P1 and P2 were not statistically different at each time point (p > 0.05). Both P1 and P2 protocols let achieve an acceptable DC after 28 days. The tested P2 can be safely used to lute indirect restorations, simplifying the removal of cement excesses.

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 Degree of Conversion of Polymer-matrix Composite assessed by FTIR Analysis

2013 ◽  
Vol 14 (1) ◽  
pp. 76-79 ◽  
Author(s):  
Mateus Rodrigues Tonetto ◽  
Marcelo Ferrarezi de Andrade ◽  
Shelon Cristina Souza Pinto ◽  
Alvaro Henrique Borges ◽  
Matheus Coelho Bandéca ◽  
...  
Keyword(s):  
Matrix Composite ◽  
Polymer Matrix ◽  
Polymer Matrix Composites ◽  
Polymer Matrix Composite ◽  
Degree Of Conversion ◽  
Matrix Composites ◽  
Ftir Analysis ◽  
Light Curing ◽  
Post Hoc ◽  
Storage Times

ABSTRACT Aims and objectives The behavior of polymer-matrix composite is dependent on the degree of conversion. The aim of this study was to evaluate the degree of conversion of two resin cements following storage at 37°C immediately, 24 and 48 hours, and 7 days after light-curing by FTIR analysis. Materials and methods The specimens were made in a metallic mold and cured with blue LED with power density of 500 mW/ cm2 for 30 seconds. The specimens were pulverized, pressed with KBr and analyzed with FTIR following storage times. Statistical analysis used ANOVA (two-way) and Tukey's post hoc. Results To the polymer-matrix composites between 24 and 48 hours does not show a significant increase (p > 0.05), however, the highest values were found after 7 days. Conclusion The polymer-matrix composites used in this study showed similarity on the degree of conversion and increased of according to the time of storage. How to cite this article Tonetto MR, Pinto SCS, de Nara Souza Rastelli A, Borges AH, Saad JRC, Pedro FLM, de Andrade MF, Bandéca MC. Degree of Conversion of Polymer-matrix Composite assessed by FTIR Analysis. J Contemp Dent Pract 2013;14(1):76-79.

scholarly journals Influence of radiant exposure values from two third generation LED curing units on polymerization profile and microhardness of orthodontic composite under ceramic and metallic brackets

2021 ◽  
Vol 26 (1) ◽  
Author(s):  
Andrés Fernando Montenegro ARANA ◽  
Barbara JUSTUS ◽  
Andrés DÁVILA-SÁNCHEZ ◽  
Michele de Oliveira SUGAHARA ◽  
Ulisses COELHO ◽  
...  
Keyword(s):  
Linear Regression Analysis ◽  
Infrared Light ◽  
Short Exposure ◽  
Third Generation ◽  
Radiant Exposure ◽  
Significant Difference ◽  
Dependent Variables ◽  
Ceramic Brackets ◽  
Light Curing ◽  
Post Hoc

ABSTRACT Introduction: Third generation of LED light curing units might be used in short exposure periods for orthodontic brackets bonding. Objective: This study evaluated the effect of the different radiant exposure (RE) values: Manufacturers’ instructions (MI), ½ MI, 1/4 MI and Turbo mode. Two third-generation LED curing units were used: VALO® and Bluephase 20i® . The degree of conversion (DC) and Vickers hardness (VHN) of an orthodontic composite (OC) (Transbond XT) under metallic (MB) or ceramic brackets (CB) were measured. Methods: OC was applied to the bracket base, which was then placed over an attenuated total reflectance (ATR) table coupled to an infrared light spectroscope, or to a glass surface for the VHN analysis. The specimens were light-cured and DC values were calculated. The VHN was obtained in a microhardness tester. The data were analyzed with 2-way ANOVA followed by Tukey’s post-hoc test (pre-set α=0.05). Linear regression analysis evaluated the relationship between RE values and dependent variables. Results: CB allowed higher DC and VHN values than MB (p< 0.001). No significant difference was noted among groups when CB were used. For MB, MI groups showed the highest DC and VHN values. A significant, but weak relationship was found between delivered RE values and dependent variables. Conclusions: The decrease in RE values from third generation LED CU did not jeopardize the DC values when CB were used, but can compromise DC and VHN values when MB are used.

scholarly journals Does an additional UV LED improve the degree of conversion and Knoop Hardness of light-shade composite resins?

2012 ◽  
Vol 06 (04) ◽  
pp. 396-401 ◽  
Author(s):  
Maria Cecília Caldas Giorgi ◽  
Flávio Henrique Baggio Aguiar ◽  
Luís Luís Soares ◽  
Airton Abrahão Martin ◽  
Priscila Christiane Suzy Liporoni ◽  
...  
Keyword(s):  
Knoop Hardness ◽  
Surface Interaction ◽  
Composite Resins ◽  
Degree Of Conversion ◽  
Third Generation ◽  
Composite Surface ◽  
Led Light ◽  
Uv Led ◽  
Significant Difference ◽  
Light Curing

ABSTRACTObjective: The purpose of this study was to evaluate the degree of conversion (DC) using FTRaman spectroscopy and the Knoop hardness (KHN) of composites cured by second and third-generation LED light curing-units (LCU), Radii Cal and Ultralume 5.Methods: Three composites (Filtek Supreme XT, Filtek Z350, and Esthet X) were selected for this study. KHN testing (n=10) was performed with 10 indentations for the top (T) and bottom (B) surfaces. For DC (n=10), both the T and B surfaces were analyzed.Results: For KHN, the three composites differed in hardens. There was a “LCU-surface” interaction, in which Radii Cal showed significantly greater hardens in the B surface. For DC, there was a “composite-surface-LCU” interaction. For the “composite” factor, there was no significant difference between the groups, except for Supreme XT-Radii Cal (T or B surfaces). For the “LCU” factor there was a significant difference for Supreme XT T surface, Ultralume 5 obtained a higher DC. For the Z350 T surface, a significant difference in the DC in which Radii Cal obtained better results. For the “surface” factor, all groups presented T surfaces with a higher DC than the B surfaces, the sole exceptions involved Esthet X-Radii Cal and Z350-Ultralume 5.Conclusion: Knowledge regarding composite composition and the characteristics of LCUs are important for effective polymerization. (Eur J Dent 2012;6:396-401)

scholarly journals Thermal Stability and Monomer Elution of Bulk Fill Composite Resins Cured from Different Irradiation Distances

2021 ◽  
Author(s):  
Elmira Jafari Navimipour ◽  
Fatemeh Pournaghi Azar ◽  
Sajjad Keshipour ◽  
Saba Nadervand
Keyword(s):  
Thermal Stability ◽  
Gas Chromatography ◽  
Weight Loss ◽  
Thermogravimetric Analysis ◽  
Composite Resins ◽  
Degree Of Conversion ◽  
Light Curing ◽  
Base Composite ◽  
Post Hoc ◽  
Thermal Stability Of

Objectives: This study aimed to evaluate the thermal stability and monomer elution of bulk fill composite resins cured at different irradiation distances. Materials and Methods: Forty cylindrical-shaped (3×4mm) specimens were fabricated from two composite resins (X-tra fil, X-tra base) and cured from 0 and 7mm distances. In 9 specimens, the degree of conversion was determined by the release of monomers. For this purpose, after curing of composites, they were immersed in 5 mL of 99.9% methanol and stored at 37°C for 24h. The eluted monomer was then analyzed by gas chromatography (GC). Also, thermal stability of one sample from each group was assessed by thermogravimetric analysis (TGA) at a rate of 10°C/min. Data were analyzed using two-way ANOVA and Tukey’s post-hoc test (P<0.05). Results: X-tra fil had significantly higher degree of conversion than X-tra base (P=0.001). Specimens cured at 7mm distance had significantly lower degree of conversion compared with those cured at 0 mm distance (P=0.001). The interaction effect of composite type and distance of light curing unit from the surface of samples was statistically significant (P=0.001). Regarding the TGA results, the lowest and the highest percentages of weight loss were detected in X-tra fil cured at 0 mm distance and X-tra base cured at 7mm distance, respectively. Conclusion: X-tra fil composite cured at 0mm distance had the highest degree of conversion and thermal stability, and X-tra base composite cured at 7mm distance had the lowest values.

Perbedaan sensitivitas tetes telinga antibiotik terhadap Pseudomonas aeruginosa pada otitis media supuratif kronik

2012 ◽  
Vol 42 (2) ◽  
Author(s):  
Anton Budhi Darmawan ◽  
Dwi Utami Anjarwati
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Otitis Media ◽  
Chronic Suppurative Otitis Media ◽  
Test Results ◽  
Sectional Study ◽  
Suppurative Otitis Media ◽  
Number Of Patients ◽  
Significant Difference ◽  
Cochran Test ◽  
Post Hoc

Background: Chronic suppurative otitis media (CSOM) is one infectious disease of the middle ear, most commonly caused by Pseudomonas aeruginosa. A high number of patients come to the ENT outpatient clinic with active benign type of CSOM. The bacteria Pseudomonas aeruginosa is capable of producing biofilm which protects itself from penetration of antibiotics, and therefore creates resistance towards antibiotics and difficult to eradicate. Objective: The aim of this study was to compare the sensitivity levels of chloramphenicol, polymyxin-neomycin, cyprofloxacin and ofloxacine against Pseudomonas aeruginosa in patients with active benign type CSOM in ENT clinic. Method: The method used was across sectional study on 25 patients, from August 2010 until December 2010. Samples were taken withear swab and then put on sensitivity test to chloramphenicol, polymyxin-neomycin, cyprofloxacin andofloxacine using the diffusion disc method. The analysis used in this study was Cochran test. Results: Results showed a significant difference in sensitivity among chloramphenicol (38,70%), polymyxinneomycin(83,87%),cyprofloxacin(90,32%)andofloxacin(58,06%)withp=0,000(p<0,05).PostHocanalysisusing the Mc Nemar indicated that there were significant differences in sensitivity betweenpolymyxin-neomycin to chloramphenicol with p=0,000 (p<0,05), ciprofloxacin to chloramphenicol andciprofloxacin to ofloxacine with p= 0,002, but there were no significant differences between cyprofloxacinto polymyxin-neomycin with p=0,687, polymyxin-neomycin to ofloxacin p=0.057 and ofloxacin tochloramphenicol p=0,109.   There were significant differences in antibiotic ear dropssensitivity to Pseudomonas aeruginosa in patients with active benign type of CSOM. Cyprofloxacin andpolymyxin-neomycin were more sensitive than ofloxacin and chloramphenicol. Keywords: Pseudomonas aeruginosa, active benign type of chronic suppurative otitis media, antibioticear drops.  Abstrak :  Latar belakang: Otitis media supuratif kronik (OMSK) merupakan penyakit infeksi kronik telinga tengah yang sering dijumpai di klinik THT. Penyebab tersering OMSK adalah bakteri Pseudomonasaeruginosa. Pseudomonas aeruginosa mempunyai kemampuan untuk membentuk biofilm yangmelindunginya dari penetrasi antibiotik sehingga menimbulkan resistensi terhadap antibiotik dan sulituntuk eradikasinya. Tujuan: Untuk mengetahui perbandingan tingkat sensitivitas kloramfenikol,polimiksin-neomisin, ciprofloksasin dan ofloksasin terhadap isolat Pseudomonas aeruginosa padapasien OMSK benigna aktif di klinik THT RSMS. Metode: Metode yang digunakan adalah crosssectional terhadap 29 pasien OMSK di klinik THT RSMS periode bulan Agustus 2010 - Desember2010. Pengambilan sampel dilakukan dengan swab telinga. Uji sensitivitas terhadap kloramfenikol,polimiksin-neomisin, ciprofloksasin dan ofloksasin dilakukan dengan metode cakram secara difusi.Analisis yang digunakan dalam penelitian ini adalah Cochran dan analisis post hoc. Hasil: Didapatkansensitivitas kloramfenikol sebesar 38,70%, polimiksin-neomisin sebesar 83,87%, ciprofloksasin sebesar90,32% dan ofloksasin sebesar 58,06% dengan p=0,01 (P<0,05), yang menunjukkan adanya perbedaansensitivitas yang bermakna antara kloramfenikol, polimiksin-neomisin, ciprofloksasin dan ofloksasinterhadap Pseudomonas aeruginosa. Analisis post hoc menggunakan Mc Nemar menunjukkan bahwaterdapat perbedaan sensitivitas yang bermakna antara tetes telinga polimiksin-neomisin terhadapkloramfenikol, dan ciprofloksasin terhadap kloramfenikol p=0,000 (p<0,05), serta terdapat perbedaanyang bermakna antara tetes telinga ciprofloksasin terhadap ofloksasin, p=0,002, tetapi tidak terdapatperbedaan yang bermakna antara ciprofloksasin terhadap polimiksin-neomisin, p=0,687, polimiksinneomisinterhadap ofloksasin p=0,057, dan kloramfenikol terhadap ofloksasin p=0,109. Kesimpulan:Terdapat perbedaan sensitivitas yang bermakna tetes telinga antibiotik terhadap Pseudomonas aeruginosa pada pasien OMSK benigna aktif. Ciprofloksasin dan polimiksin-neomisin tetes telinga mempunyai sensitivitas yang lebih baik dibanding ofloksasin dan kloramfenikol. Kata kunci: Pseudomonas aeruginosa, otitis media supuratif kronik, tetes telinga antibiotik 

Effect of LED Light-Curing Spectral Emission Profile on Light-Cured Resin Cement Degree of Conversion

2020 ◽  
Author(s):  
RQ Ramos ◽  
RR Moraes ◽  
GC Lopes
Keyword(s):  
Clinical Relevance ◽  
Degree Of Conversion ◽  
Resin Cement ◽  
Light Activation ◽  
Spectral Emission ◽  
Led Light ◽  
Emission Profile ◽  
Light Curing

Clinical Relevance The use of multipeak LED light-curing guarantees efficiency on light activation of Ivocerin-containing light-cured resin cement.

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