Degree of Conversion, Depth of Cure, and Color Stability of Experimental Dental Composite Formulated with Camphorquinone and Phenanthrenequinone Photoinitiators

As resinas compostas fotopolimerizáveis têm tido cada vez mais indicações na odontologia restauradora devido às vantagens que apresentam. Porém variações na técnica de fotoativação, densidade de energia, intensidade da luz e tempo de irradiação podem gerar polimerização incompleta, o que pode resultar em uma resina composta com alta porosidade, pouca dureza, baixo polimento, alta capacidade de pigmentação ou efeitos tóxicos na polpa. Este estudo tem por objetivo analisar o efeito do tempo de polimerização na pigmentação extrínseca de três resinas compostas fotopolimerizáveis. Utilizando uma fonte de LED, foram confeccionados 180 espécimes de resina composta microhíbrida, nanohíbrida e nanoparticulada, com diferentes protocolos de polimerização. Os espécimes foram subdivididos em grupos de acordo com o agente pigmentante. Com o uso de um colorímetro, foram analisados quanto à mudança de cor (ΔE). Os dados foram submetidos ao teste ANOVA e Duncan (α=0,05). A resina composta microhíbrida apresentou os menores valores de ΔE em comparação à nanoparticulada e à nanohíbrida quando imersos em vinho. Quanto maior o tempo de polimerização menores valores de ΔE foram obtidos. Não somente o tempo de polimerização influencia no grau de pigmentação, mas também fatores intrínsecos às resinas compostas tais como carga, agente fotoiniciador e matriz orgânica.Descritores: Autocura de Resinas Dentárias; Materiais Dentários; Pigmentação.ReferênciasMatson MR, Matson AMFP. Avaliação do grau de conversão de resinas compostas quando ativadas por luz halógena: método convencional, alta potência e método “soft”. Rev Inst Ciênc Saúde. 2006;24(4):307-11.Delaviz Y, Finer Y, Santerre JP. Biodegradation of resin composites and adhesivesby oral bacteria and saliva: A rationale for new material designs that consider the clinical environment and treatment challenges. Dent Mater. 2014;30(1):16-32.Nahsan FPS, Ueda JK, Silva JO, Schimitt VL, Naufel FS, Formighieri LA et al. Estabilidade de cor de resina composta após imersão em café, água e solução de clorexidina. Rev Bras Pesq Saúde. 2009;11(2):13-7.Al Kheraif AA, Qasim SS, Ramakrishnaiah R, Rehman I. Effect of different beverages on the color stability and degree of conversion of nano and microhybrid composites. Dent Mater J. 2013;(32)2:326-31.Ceballos L, Fuentes MV, Tafalla H, Martínez A, Flores J, Rodríguez J. Curing effectiveness of resin composites at different exposure times using LED and halogen units. Med Oral Pathol Oral Cir Bucal 2009;14(1):e51-6.Rahiotis C, Patsouri K, Silikas N, Kakaboura A. Curing efficiency of high- intensity light-emitting diode (LED) devices. J Oral Sci. 2010; 52(2):187-95.Sgarbi SC, Pereira SK, Martins JMH, Oliveira MAC, Mazur RF. Degree of conversion of resin composites light activated by halogen light and led analyzed by ultraviolet spectrometry. Rev Clín Pesq Odontol. 2010;6(3):223-30.Caldarelli PG, Beltrani FC, Santos FA, Shibayama R, Hoepper MG. Manchamento de uma resina composta e sua Relação com o efeito da intensidade da luz Emitida por aparelhos fotopolimerizadores de Lâmpada halôgena. Rev Fac Odontol Aracatuba. 2011;(32)2:44-8.Valentini F, Oliveira SGD, Guimarães GZ, Barbosa RPS, Moraes RR. Effect of surface sealant on the color stability of composite resin restorations. Braz Dent J. 2011;22(5):365-68.Freitas ABDA, Gomes HR, Guimarães FBR, Marinho VA, Barros LM. Influência do tipo de aparelho fotopolimerizador na absorção de água por restaurações de resina composta. Rev Inst Ciênc Saúde. 2008;(26)1:65-9.Porto ICCM, Soares LES, Martin AA, Cavalli V, Liporoni PCS. Influence of the photoinitiator system and light photoactivation units on the degree of conversion of dental composites. Braz Oral Res. 2010;24(4):475-81.Pequeno JHP, Araújo GS, Neri JR, Bomfim AGM, Mendonça JS, Santiago SL. Efeito dos protocolos de fotoativação na dureza de uma resina composta nanoparticulada. ROBRAC. 2012;21(56):394-97.Uhl A, Mills RW, Rzanny AE, Jandt KD. Time dependence of composite shrinkage using halogen and LED light curing. Dent Mater. 2005;21(3):278-86.Eick JD, Kotha SP, Chappelow CC, Kilway KV, Giese GJ, Glaros AG et al. Properties of silorane-based dental resins and composites containing a stressreducing monomer. Dent Mater. 2007;23(8):1011-17.Neumann MG, Schmitt CC, Ferreira GC, Correa IC. The initiating radical yields and the efficiency of polymerization for various dental photoinitiators excited by different lightcuring units. Dent Mater. 2006;22(6):576-84.Asmussen E, Peutzfeldt A. Influence of composition on rate of polymerization contraction of light-curing resin composites. Acta Odontol Scand. 2002;60(3):146-50.Silva EH, Albuquerque RC, Lanza LD, Vieira GC, Peixoto RT, Alvim HH et al. Influence of different light sources on the conversion of composite resins. Indian J Dent Res. 2011;22(6):790-94.Souza E, Espíndola M, Diegoli NM, Kuroshima KN. Avaliação da alteração de cor de diferentes compósitos restauradores - influência de corantes usados na cavidade oral - estudo in vitro. RGO. 2006;54(1):43-6.Salvego RN, Dias RPB. Figueiredo JLG. Estabilidade de cor de resinas compostas no processo de manchamento e clareamento, Rev Dental Press Estét. 2013;10(3):54-62.Firoozmandi LM, Balducci I, Araújo MAM. Influência da Fotopolimerização e da Cor da Resina Composta na Microdureza. Pesq Bras Odontoped Clín Integr. 2009;9(1):37-42.Anfe TEA, Agra CM, Vieira GF. Comparação de duas técnicas de fotoativação na sorção e solubilidade de resinas compostas em solução de etanol. J Biodent Biomater. 2011;1(1):61-7.Villalta P, Lu H, Okte Z, Garcia-Godoy F, Powers JM. Effects of staining and bleaching on color change of dental composite resins. J Prosthet Dent. 2006;95(2):137-42.Barghi N, Berry T, Hatton C. Evaluation intensity output of curing lights in private dental offices. J. am. dent. assoc. 1994;125(7):992-96.Santini A, Miletic V, Swift MD, Bradley M. Degree of conversion and microhardness of TPO-containing resin-based composites cured by polywave and monowave LED units. J Dent. 2012;40(7):577-84.

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The Photoinitiators Used in Resin Based Dental Composite—A Review and Future Perspectives

Polymers ◽

10.3390/polym13030470 ◽

2021 ◽

Vol 13 (3) ◽

pp. 470

Author(s):

Andrea Kowalska ◽

Jerzy Sokolowski ◽

Kinga Bociong

Keyword(s):

Current Knowledge ◽

Biomechanical Properties ◽

Degree Of Conversion ◽

Dental Composite ◽

Polymerization Process ◽

Dental Composites ◽

Dental Resin ◽

Dental Resins ◽

Light Curing

The presented paper concerns current knowledge of commercial and alternative photoinitiator systems used in dentistry. It discusses alternative and commercial photoinitiators and focuses on mechanisms of polymerization process, in vitro measurement methods and factors influencing the degree of conversion and hardness of dental resins. PubMed, Academia.edu, Google Scholar, Elsevier, ResearchGate and Mendeley, analysis from 1985 to 2020 were searched electronically with appropriate keywords. Over 60 articles were chosen based on relevance to this review. Dental light-cured composites are the most common filling used in dentistry, but every photoinitiator system requires proper light-curing system with suitable spectrum of light. Alternation of photoinitiator might cause changing the values of biomechanical properties such as: degree of conversion, hardness, biocompatibility. This review contains comparison of biomechanical properties of dental composites including different photosensitizers among other: camphorquinone, phenanthrenequinone, benzophenone and 1-phenyl-1,2 propanedione, trimethylbenzoyl-diphenylphosphine oxide, benzoyl peroxide. The major aim of this article was to point out alternative photoinitiators which would compensate the disadvantages of camphorquinone such as: yellow staining or poor biocompatibility and also would have mechanical properties as satisfactory as camphorquinone. Research showed there is not an adequate photoinitiator which can be as sufficient as camphorquinone (CQ), but alternative photosensitizers like: benzoyl germanium or novel acylphosphine oxide photoinitiators used synergistically with CQ are able to improve aesthetic properties and degree of conversion of dental resin.

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Color stability, opacity and degree of conversion of pre-heated composites

Journal of Dentistry ◽

10.1016/j.jdent.2010.12.001 ◽

2011 ◽

Vol 39 ◽

pp. e25-e29 ◽

Cited By ~ 25

Author(s):

Fabrício Mariano Mundim ◽

Lucas da Fonseca Roberti Garcia ◽

Diogo Rodrigues Cruvinel ◽

Fabrício Augusto Lima ◽

Luciano Bachmann ◽

...

Keyword(s):

Color Stability ◽

Degree Of Conversion

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Evaluation of depth of cure and Knoop hardness in a dental composite photo-activated using different methods

Brazilian Dental Journal ◽

10.1590/s0103-64402004000300007 ◽

2004 ◽

Vol 15 (3) ◽

pp. 199-203 ◽

Cited By ~ 20

Author(s):

Andresa Carla Obici ◽

Mário Alexandre Coelho Sinhoreti ◽

Lourenço Correr Sobrinho ◽

Mario Fernando de Goes ◽

Simonides Consani

Keyword(s):

Composite Resin ◽

Continuous Light ◽

Acrylic Resin ◽

Knoop Hardness ◽

Dental Composite ◽

Intermittent Light ◽

Light Emitting ◽

Depth Of Cure ◽

The Matrix ◽

Hardness Values

The aim of this study was to evaluate the depth of cure and Knoop hardness in the P60 composite resin photo-activated using different methods. A bipartite brass matrix (3 mm in diameter X 11 mm in height) was filled with the composite and photo-activation was performed using continuous light, exponential light, intermittent light, plasma arc curing (PAC) or light-emitting diodes (LED). After opening the matrix, the uncured material was removed with a steel spatula and the polymerized composite was measured using a pachymeter. The specimens were then included in self-curing acrylic resin and worn longitudinally and the hardness was measured on the surface and at depths of 1, 2, 3, 4 and 5 mm. The data were analyzed by ANOVA and Tukey's test (5%). The results showed that the depth of cure was higher with the intermittent light, followed by continuous light, exponential light, PAC and LED methods. Up to a depth of 2 mm, all methods revealed similar hardness values, but there were differences between them at other depths, at which LED demonstrated the lowest values followed by PAC.

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Physical–mechanical evaluation of a microhybrid and a nanofilled composite light activated by quartz-halogen tungsten and light-emitting diode

Journal of Composite Materials ◽

10.1177/0021998318793720 ◽

2018 ◽

Vol 53 (7) ◽

pp. 981-990

Author(s):

Fernanda P Ritto ◽

Eduardo Moreira da Silva ◽

Hélio Rodrigues Sampaio-Filho ◽

Raimundo A Lacerda ◽

Márcio AP Borges ◽

...

Keyword(s):

Electron Microscopy ◽

Mechanical Properties ◽

Scanning Electron Microscopy ◽

Nuclear Magnetic Resonance ◽

Light Emitting Diode ◽

Degree Of Conversion ◽

Dental Composite ◽

Polymerization Shrinkage ◽

Light Emitting ◽

Scanning Electron

The aim of this study was to characterize organic and disperse phase of a microhybrid (Mh – Filtek Z250) and a nanofilled (Nf – Filtek Z350) dental composite and analyze the influence of two LCUs (QHT-quartz-halogen tungsten and LED – light-emitting diode) on its physical–mechanical properties (degree of conversion, polymerization shrinkage, Vickers hardness and diametral tensile strength). Surface morphology was studied by scanning electron microscopy. The disperse phase content was measured using thermogravimetric analysis (TGA) and the organic fractions were qualitatively analyzed by nuclear magnetic resonance spectroscopy. Physical–mechanical properties were analyzed varying dental composite and LCU: Mh-QHT, Nf-QHT, Mh-LED and Nf-LED. The degree of conversion was evaluated using Raman spectrophotometry and polymerization shrinkage was measured by water picnometry. Mechanical behavior was analyzed by Vickers microhardness and diametral tensile testing. Scanning electron microscopy analysis showed similar microstructure of the materials mainly composed with different-sized particles dispersed within methacrylate matrix. Thermogravimetric analysis shows 80.13% of inorganic fraction for microhybrid composite and 75.29% for nanofilled. Nuclear magnetic resonance analysis showed similar organic structure for composites and did not show the presence of the monomer TEGDMA. Different light sources did not influence the tested properties, but considering different composites, nanofilled showed the highest degree of conversion (Gr 2:77%, Gr 4: 79.4%). The study shows that when the optimum radiant exposure (24 J/cm2) was used for polymerization of composites, regardless of the polymerization source, the properties of these resin materials showed satisfactory and similar results in relation to the conversion of polymers, polymerization shrinkage and mechanical behavior.

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Color stability and degree of conversion of a novel dibenzoyl germanium derivative containing photo-polymerized resin luting cement

Journal of Applied Biomaterials & Functional Materials ◽

10.1177/2280800020917326 ◽

2020 ◽

Vol 18 ◽

pp. 228080002091732 ◽

Cited By ~ 1

Author(s):

Fahad Alkhudhairy ◽

Fahim Vohra ◽

Mustafa Naseem ◽

Mosa Mohammed Owais ◽

Abdulmajeed H Bin Amer ◽

...

Keyword(s):

Color Stability ◽

Color Difference ◽

Degree Of Conversion ◽

Resin Cement ◽

Resin Cements ◽

Luting Agents ◽

Multiple Comparison Test ◽

Luting Cement ◽

Color Components

Aim: To compare the color stability and degree of conversion (DC) of a resin cement containing a dibenzoyl germanium derivative photo-initiator (Variolink Esthetic) to resin cements containing conventional luting agents. Materials and Method: Spectrophotometry and Fourier transform infrared spectroscopy (FTIR) were used to compare the color stability and DC, respectively, of Variolink Esthetic compared to Calibra, Variolink-N, and NX3 resin cements. Ten specimens (1 × 2 mm2) of each resin cement were photo-polymerized and then subjected to color stability assessments. In addition, 30 samples of each of the four resin cements were prepared and then immersed in three staining solutions (tea, coffee, and distilled water) for two weeks. Changes in color for the immersed versus non-immersed specimens (control specimens) were determined by comparing ΔL (lightness), Δa, and Δb (color components), and an overall ΔE (color difference) obtained from spectrophotometry assays. One-way analysis of variance and a multiple comparison test (Tukey’s test) were used to analyze color stability and DC data. NX3 and Variolink Esthetic resin cements exhibited significantly lower values compared to the dual cured resin cements (Variolink-N and Calibra). Results: The highest DC values were observed among the photo-polymerized samples of Variolink Esthetic (87.18 ± 2.90%), while the lowest DC values were observed among the Variolink-N samples (44.55 ± 4.33%). Conclusion: The resin cement, Variolink Esthetic, containing a novel dibenzoyl germanium derivative photo-initiator exhibited superior color stability ( p < 0.05) and a higher DC than other resin cements containing conventional luting agents in an in vitro setting.

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