Comparação do efeito da ciclagem de pH e escovação simulada em superfície de resinas compostas convencional e bulk fill : Comparison of pH cycling and simulated toothbrushing effect on conventional and bulk fill composite resin surface

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UNIVERSIDADE ESTADUAL DE CAMPINAS

FACULDADE DE ODONTOLOGIA DE PIRACICABA

Larissa Daniela Orlando

COMPARAÇÃO DO EFEITO DA CICLAGEM DE PH E ESCOVAÇÃO SIMULADA EM SUPERFÍCIE DE RESINAS COMPOSTAS CONVENCIONAL

E BULK FILL

COMPARISON OF PH CYCLINGAND SIMULATED TOOTHBRUSHING EFFECT ON CONVENTIONAL AND BULK FILL COMPOSITE RESIN

SURFACE

Piracicaba 2020

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COMPARAÇÃO DO EFEITO DA CICLAGEM DE PH E ESCOVAÇÃO SIMULADA EM SUPERFÍCIE DE RESINAS COMPOSTAS CONVENCIONAL

E BULK FILL

COMPARISON OF PH CYCLING AND SIMULATED TOOTHBRUSHING EFFECT ON CONVENTIONAL AND BULK FILL COMPOSITE RESIN

SURFACE

Orientador: Prof. Dr. Luís Roberto

Marcondes Martins

ESTE EXEMPLAR CORRESPONDE À VERSÃO FINAL DA DISSERTAÇÃO DEFENDIDA PELA ALUNA LARISSA DANIELA ORLANDO E ORIENTADA PELO PROF. DR. LUÍS ROBERTO MARCONDES MARTINS.

Dissertação apresentada à Faculdade de Odontologia de Piracicaba, da Universidade Estadual de Campinas como parte dos requisitos exigidos para a obtenção do título de Mestra em Clínica Odontológica, na Área de Dentística.

Dissertation presented to the Piracicaba Dental School of the University of Campinas in partial fulfillment of the requirements for the degree of Master in Clinical Dentistry, in Restorative Dentistry area.

Piracicaba 2020

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Dedicatória

Dedico este trabalho a Deus e minha família, que sempre me fortalecem nos momentos de maior dificuldade.

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O presente trabalho foi realizado com apoio da Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES) - Código de financiamento 001.

Ao Prof. Dr. Luis Roberto Marcondes Martins, pela orientação durante toda a pesquisa desenvolvida. Por todo ensinamento.

Agradeço também ao meu amigo Rodrigo Barros Esteves Lins, pela ajuda e orientação durante toda a pesquisa.

À Faculdade de Odontologia de Piracicaba, na pessoa do seu Diretor Prof. Dr. Francisco Haiter.

A todas as pessoas que participaram, de alguma forma, na pesquisa. A minha família, por apoiar sempre minhas escolhas.

Ao meu namorado Gabriel, por sempre me incentivar a ter forças para conquistar meus sonhos e enfrentar as dificuldades.

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RESUMO

O presente estudo teve como objetivo avaliar alterações de superfície de resinas compostas convencional e Bulk Fill submetidas à ciclagem de pH e escovação simulada. Foram avaliadas três resinas compostas: Filtek Z250 XT (Z250), Tetric N-Ceram bulk fill (TNC) e SonicFill (SF), divididas em 6 grupos (n=10), 2 grupos Z250, 2 grupos TNC e 2 grupos SF. As amostras foram confeccionadas em formato de disco (15x4mm), fotopolimerizadas e polidas superficialmente apenas na superficie de topo, (face em que o fotopolimerizador incidiu diretamente). Todas as amostras foram analisadas na face polida por microdureza e rugosidade superficial em três tempos: inicial, após a ciclagem de pH e após a escovação simulada. A leitura inicial foi feita no centro das amostras, após a leitura metade da área da superfície de topo de cada amostra foi isolada com uma fita vermelha, para ter uma comparação dos lados no final do estudo. Apenas 3 grupos (um grupo de cada resina), foramsubmetidos à ciclagem de pH, os outro 3 grupos ficaram armazenados em água deionizada. Foi realizada uma nova leitura de microdureza (KHN) e rugosidade (Ra) na superfície de topo no lado exposto da amostra (lado sem a fita) em todos os grupos. Após a nova leitura todos os grupos passaram pelo processo de escovação simulada. Foram realizados 100.000 ciclos de escovação simulada em todos os grupos. Após a escovação uma nova leitura foi feita no lado exposto da superfície de topo. Uma amostras de cada grupo foi selecionadas aleatoriamente para uma análise ilustrativa do Microscópio Eletrônico de Varredura (MEV), as amostras foram metalizadas para permitir sua vizualização no MEV e foi obtida uma fotomicrografia com aumento de 1000x em cada área da amostra. Os dados obtidos de microdureza e rugosidade foram analisados estatisticamente pelo teste não- paramétrico Kruskal-Wallis para comparação entre os grupos com e sem ciclagem de pH dentro dos tempos (α=5%). Apenas o grupo SF submetido à ciclagem de pH obteve um aumento estatisticamente significativo na rugosidade de superfície, porém todos os grupos tiveram aumento estatisticamente significativo da rugosidade de superfície após a escovação. Os grupos Z250 e SF que passaram pela ciclagem de pH, além dos grupos TNC, obtiveram uma diminuição estatisticamente significativa na microdureza de superfície, mas não diferiu estatisticamente após a escovação. Nos dados obtidos pelo Microscópio Eletrônico de Varredura (MEV), observamos que nas resinas Z250 e TNC a área que foi exposta difereda área isolada, e as imagens da área exposta são visualmente semelhantes. Na resina SF, a área exposta também é visualmente diferente

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diferente da área que não passou pela ciclagem. Pôde-se concluir que a ciclagem de pH e a escovação simulada causaram degradação superficial das resinas compostas convencional e bulk fill.

Palavras-chave: Escovação dentária, Restauração dentária permanente, Materiais dentários, Resina composta.

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ABSTRACT

The following study had the objective to evaluate surface alterations in samples of Bulk Fill composite resin subject to pH cycling and simulated toothbrushing. Three

composite resins were evaluated: Filtek Z250 XT(Z250), Tetric N-Ceram Bulk

fill(TNC) and SonicFill(SF), divided in 6 groups(n=10), 2 groups Z250, 2 groups TNC and 2 groups SF. The samples were made in a disc shape (15x4mm), light cured and polished superficially in the superior top face only (face where the curing light directly hit). All the samples were analysed on the polished face by microhardness and surface roughness at three stages: initial, after pH cycling and after simulated toothbrushing. The initial reading was done right in center of the sample, after these reading half of the top surface area of each sample was isolated with red tape, to get a comparison of both sides at the end of the study. Only 3 groups(1 of each composite) were subjected to pH cycling. The other 3 were stored in deionized water. A new microhardness (KHN) and surface roughness (Ra) reading was performed on the top surface on the exposed side(side without the tape) of the sample in all groups. After the new readings all the groups went through the simulated toothbrushing process. A 100.000 cycles of simulated toothbrushing were performed in all the groups. After the toothbrushing a new reading was performed at the exposed side of the top surface. One sample from each group was selected at random for an illustrative analysis of the Scanning Electron Microscope (SEM), the samples were metallized to allow visualization in the SEM and a photomicrograph with a 1000x magnification was obtained in each sample area. The obtained data of microhardness and roughness were analysed statistically by the

nonparametric Kruskal-Wallis test for comparison between the groups with and without the pH cycling within the stages (α=5%). Only the SF group subjected to pH cycling had a statistically significant increase of the surface roughness, but all the groups had a statistically significant increase of surface roughness after the toothbrushing. The Z250 and SF groups that went through the pH cycling, in addition to both TNC groups, obtained a statistically significant decrease of the surface microhardness, but did not change statistically after brushing. In the data obtained by the Scanning Electron

Microscope (SEM), we observed that in resins Z250 and TNC the area that was exposed differs from the isolated area, and the images of the exposed area are visually similar. In SF resin, the exposed area is also visually different from the isolated area, however the exposed area that has undergone cycling is also visually different from the area that has not undergone cycling. We concluded that pH cycling and simulated toothbrushing caused superficial degradation of Bulk Fill composite resins.

Keywords: Toothbrushing, Dental restoration permanent, Dental materials, Composite resins.

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1 INTRODUÇÃO 11

2 ARTIGO: Effect of pH cycling and simulated toothbrushing on 14 Bulk Fill composite resin surface

3 CONCLUSÃO 34

REFERÊNCIAS 35

APÊNDICE I- Metodologia Ilustrada 37

ANEXOS

ANEXO 1- Comprovante de submissão 39

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1 INTRODUÇÃO

As resinas compostas estão sendo cada vez mais utilizadas entre os dentistas em tratamentos restauradores, pela sua facilidade de manipulação e sua longevidade. Portanto elas têm atraído grande interesse entre os pesquisadores (LANGALIA et al., 2015). Resinas Compostas são materiais poliméricos constituídos por uma matriz orgânica reforçada por uma dispersão de vidros, cristais ou partículas de carga (matriz inorgânica), sendo então esses dois componentes unidos por um agente de união, os silanos orgânicos. A matriz orgânica tem como principal componente os monômeros, cuja função é fornecer as características manipulativas e físicas desejadas. A matriz inorgânica é responsável pela rigidez superficial, dando maior resistência a compressão e tração, aumentando a durabilidade e o desempenho clínico. O fotoiniciador das resinas, é a canforoquinona, utilizada sozinha ou junto com outros fotoiniciadores, que ao reagir com a amina terciária, formam radicais livres, iniciando a polimerização, permitem o controle do tempo de trabalho e o uso de diferentes cores. (PEREIRA et al., 2018).

Embora esses materiais apresentem propriedades mecânicas e físicas adequadas, alguns aspectos clínicos podem determinar o sucesso ou falha das restaurações dentárias em resina composta. Um fator é a espessura do incremento de resina inserida na cavidade e a polimerização eficaz de todos os incrementos. A fotopolimerização adequada é indispensável para que as propriedades mecânicas das resinas compostas sejam satisfatórias e apresentem clinicamente uma maior longevidade do material (ALQAHTANI et al.,2015).

A técnica utilizada para restaurações direta, é a técnica por incremento, em que são realizados incrementos de até 2 mm de espessura e fotoativados em seguida de acordo com as especificações do fabricante de cada resina composta. Ela é utilizada para minimizar a tensão de polimerização (contração) causada durante a fotoativação. Porém essa técnica quando realizada em restaurações posteriores extensas, acaba sendo muito demorada. (PEREIRA et al., 2018).

Recentemente a Odontologia Restauradora tem sido apresentada a um novo grupo de materiais denominados de “Bulk Fill”, que são resinas compostas que tiveram sua matriz orgânica modificada (PEREIRA et al., 2018; TSUJIMOTO et al., 2018; LINS et al., 2019). Se propõem a serem utilizadas em uma só camada de até 6mm de espessura, devido a sua capacidade de gerar menor contração linear, volumétrica de polimerização (que gera menor tensão), maior translucidez melhorando a transição da

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luz pelo corpo do material, a utilização de fotoiniciadores alternativos, além do uso de fotoiniciadores adicionais, a resina composta bulk fill também apresenta reduzida quantidade de partículas de carga, além de tamanho maior (ABBASI, et al., 2018). Além disso, apresenta um menor risco dos efeitos indesejáveis como bolhas formadas durante as restaurações feitas por incrementos e possui o tempo operacional reduzido (CHESTERMAN et al., 2017). Porém essas modificações na sua matriz orgânica podem afetar diretamente a resistência ao desgaste, a rugosidade e a degradação química, sendo que estes fatores são normalmente interligados (BENETTI et al., 2015).

O desgaste é uma preocupação muito comum quando utilizamos a resina composta principalmente em restaurações de dentes posteriores. O desgaste ocorre principalmente em hábitos parafuncionais, mastigação e escovação. Os sinais clínicos de desgastes das restaurações são: perda de anatomia, aumento da rugosidade da superfície, acúmulo de placa, manchamento, alterações microscópicas da superfície e trincas (TABATABAEI et al., 2016). Na literatura científica encontram-se diversos métodos laboratoriais utilizados para alterar a superfície de materiais, dentre eles, a escovação simulada, e para avaliar o desgaste por ele formado utilizam-se testes de rugosidade e microdureza. Esses testes apresentam dados comparativos sobre a resistência à abrasão de materiais restauradores diretos e indiretos, verificação da qualidade da superfície resultante, os quais estão diretamente relacionados à carga submetida pelo método mecânico, as propriedades de superfície do material restaurador e o tipo de material a ser avaliado dependendo da sua composição química (DALLA- VECCHIA, et al., 2017; HEINTZE et al., 2019).

A maioria das resinas compostas possuem como base da sua matriz orgânica o BIS-GMA, sendo um monômero hidrofílico, possui um grau maior de sorção de água e outros líquidos, assim sendo um fator relevante para tornar as resinas compostas susceptíveis a degradações químicas, influenciando de forma irreversível nas propriedades dos materiais. Outro fator que afeta a integridade da superfície das resinas compostas, alterando cor, microdureza e causando perda de estrutura, é o baixo pH. Isso se dá pela difusão de moléculas através da estrutura polimérica na matriz orgânica e resulta no amolecimento da resina (XAVIER et al., 2016). Na cavidade bucal o meio químico é um aspecto que exerce influência significativa sobre o processo de degradação dos materiais restauradores resinosos, pois alguns fatores como o baixo pH, decorrente da ação dos microrganismos cariogênicos, da dieta e da composição iônica da saliva, causam o enfraquecimento do material restaurador (GHAVAMI-LAHIJI et

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al., 2017).Devido à importância em simular as condições da cavidade bucal, alguns pesquisadores (PRAKKI, ET al., 2007 )propuseram a associação da ciclagem de pH a um desafio mecânico, como a escovação simulada. Modelos in vitro de ciclagem de pH ainda são amplamente utilizados, pois simulam a dinâmica de perda e ganho de mineral resultante de uma condição de desafio cariogênico envolvida na formação da lesão de cárie, situação que também estão sujeitos os materiais restauradores. Os resultados obtidos por esses estudos confirmaram que um regime de ciclagem de pH pode influenciar algumas propriedades da superfície de resinas compostas (ISHIKIRIAMA et al., 2014; RAO et al., 2015).

A crescente procura dos pacientes por restaurações estéticas, mesmo em áreas posteriores, torna necessária a realização de pesquisas para melhor entendimento das propriedades e aplicações destes materiais submetido a eventos desafiadores. Considerando que a resina composta é comumente o material de escolha para restaurações de lesões cariosas e não cariosas e que o desgaste de áreas livres de contato oclusal é decorrente principalmente do processo químico e de abrasão e como os estudos mensionados envolvem apenas resinas compostas convencionais, este presente estudo apresenta como objetivo principal avaliar as alterações de superfície (rugosidade superficial e microdureza) de resinas compostas convencional e Bulk Fill submetidas à ciclagem de pH e escovação simulada.

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2 ARTIGO

Comparison of pH cyclingand simulated toothbrushing effect on conventional and bulk fill composite resin surface.

Artigo submetido ao Journal of Dentistry (Anexo I)

Larissa Daniela Orlando1; Rodrigo Barros Esteves Lins2; Luís Roberto Marcondes Martins3

1

DDS, MSc student - Department of Restorative Dentistry, Piracicaba Dental School – University of Campinas (UNICAMP), Piracicaba - São Paulo, Brazil

2

DDS, MSc, PhD - Department of Restorative Dentistry, Piracicaba Dental School – University of Campinas (UNICAMP), Piracicaba - São Paulo, Brazil

3

DDS, MSc, PhD - Department of Restorative Dentistry, Piracicaba Dental School – University of Campinas (UNICAMP), Piracicaba - São Paulo, Brazil

Comparison of pH cyclingand simulated toothbrushing effect on conventional and Bulk Fill composite resin surface.

Corresponding Author: Larissa Daniela Orlando larissa-orlando@hotmail.com

Department of Restorative Dentistry, Piracicaba Dental School – University of Campinas

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ABSTRACT

The following study had the objective to evaluate surface alterations in samples of Bulk Fill composite resin subject to pH cycling and simulated toothbrushing. Three composite resins were evaluated: Filtek Z250 XT(Z250), Tetric N-Ceram Bulk fill(TNC) and SonicFill(SF), divided in 6 groups(n=10), 2 groups Z250, 2 groups TNC and 2 groups SF. The samples were made in a disc shape (15x4mm), light cured and polished superficially in the superior top face only (face where the curing light directly hit). All the samples were analysed on the polished face by microhardness and surface roughness at three stages: initial, after pH cycling and after simulated toothbrushing. The initial reading was done right in center of the sample, after these reading half of the top surface area of each sample was isolated with red tape, to get a comparison of both sides at the end of the study. Only 3 groups(1 of each composite) were subjected to pH cycling. The other 3 were stored in deionized water. A new microhardness (KHN) and surface roughness (Ra) reading was performed on the top surface on the exposed side(side without the tape) of the sample in all groups. After the new readings all the groups went through the simulated toothbrushing process. A 100.000 cycles of simulated toothbrushing were performed in all the groups. After the toothbrushing a new reading was performed at the exposed side of the top surface. One sample from each group was selected at random for an illustrative analysis of the Scanning Electron Microscope (SEM), the samples were metallized to allow visualization in the SEM and a photomicrograph with a 1000x magnification was obtained in each sample area. The obtained data of microhardness and roughness were analysed statistically by the nonparametric Kruskal-Wallis test for comparison between the groups with and without the pH cycling within the stages (α=5%). Only the SF group subjected to pH cycling had a statistically significant increase of the surface roughness, but all the groups had a statistically significant increase of surface roughness after the toothbrushing. The Z250 and SF groups that went through the pH cycling, in addition to both TNC groups, obtained a statistically significant decrease of the surface microhardness, but did not change statistically after brushing. In the data obtained by the Scanning Electron Microscope (SEM), we observed that in resins Z250 and TNC the area that was exposed differs from the isolated area, and the images of the exposed area are visually similar. In SF resin, the exposed area is also visually different from the isolated area, however the exposed area that has undergone cycling is also visually different from the area that has not undergone cycling We concluded that pH cycling and simulated toothbrushing caused superficial degradation of Bulk Fill composite resins.

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Acknowledgment

This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nivel Superior – Brasil (CAPES) – Finace Code 001.

Introduction

Composite resins are being increasingly used among dentists in restoration treatments, due to their ease of handling and their longevity. They have attracted great interest among researchers [1]. Composite resins are polymeric materials made up of an organic matrix reinforced by a dispersion of glass, crystals or charge lenses (inorganic matrix), these two components being joined by a bonding agent, or organic silanes. An organic matrix has as main components monomers, whose function is provided as manipulative and desirable resources. An inorganic matrix is responsible for surface rigidity, giving greater resistance to compression and reduction, reducing the capacity and clinical performance. The photoinitiator of resins is a camphorquinone, used alone or together with other photoinitiators, which reacts with a tertiary amine, forms free radicals, initiating a polymerization, initiating a polymerization, using working time control and the use of different nuclei [4].

.Although these materials have adequate mechanical and physical properties, some clinical aspects can determine the success or failure of dental composite restorations. One factor is the thickness of the resin increment inserted in the cavity and the effective polymerization of all increments. Adequate photopolymerization is indispensable so that the mechanical properties of composite resins are satisfactory and have a clinically greater longevity of the material [5].

The technique used for direct restorations is the incremental technique, in which increments of up to 2 mm in thickness are made and then photoactivated in accordance with the manufacturer's specifications for each composite resin. It is used to minimize the polymerization stress (contraction) caused during photoactivation. However, this technique, when performed in extensive posterior restorations, ends up taking a long time [4].

Recently, Restorative Dentistry has been introduced to a new group of materials called “Bulk Fill”, which are composite resins that have had their organic matrix modified [4][6][7]. They are proposed to be used in a single layer up to 6mm thick, due

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to its ability to generate less linear, volumetric polymerization contraction (which generates less tension), greater translucency improving the light transition through the material body, the use of alternative photoinitiators, in addition to the use of additional photoinitiators, the bulk fill composite resin also has a reduced amount of filler particles, in addition to a larger size [2]. In addition, it has a lower risk of undesirable effects such as bubbles formed during restorations done in increments and has reduced operational time [3]. However, these changes in its organic matrix can directly affect wear resistance, roughness and chemical degradation, and these factors are usually interconnected [8].

Wear is a very common concern when using composite resin mainly in posterior tooth restorations. Wear occurs mainly in parafunctional habits, chewing and brushing. The clinical signs of wear on the restorations are: loss of anatomy, increased surface roughness, plaque buildup, staining, microscopic changes to the surface and cracks [9]. In the scientific literature there are several laboratory methods used to alter the surface of materials, among them, the simulated brushing, and to assess the wear it forms, roughness and microhardness tests are used. These tests present comparative data on the abrasion resistance of direct and indirect restorative materials, verification of the resulting surface quality, which are directly related to the load submitted by the mechanical method, the surface properties of the restorative material and the type of material to be evaluated depending on its chemical composition[10][11]).

Most composite resins have BIS-GMA as the base of their organic matrix, being a hydrophilic monomer, it has a higher degree of water and other liquid sorption, thus being a relevant factor in making composite resins susceptible to chemical degradation, influencing irreversibly in the properties of the materials. Another factor that affects the surface integrity of composite resins, changing color, microhardness and causing loss of structure, is the low pH. This is due to the diffusion of molecules through the polymeric structure in the organic matrix and results in the softening of the resin [12]. In the oral cavity, the chemical environment is an aspect that has a significant influence on the degradation process of resin restorative materials, as some factors, such as low pH, due to the action of cariogenic microorganisms, diet and the ionic composition of saliva, cause the weakening restorative material [13]. Due to the importance of simulating the conditions of the oral cavity, some researchers [22] proposed the association of pH cycling with a mechanical challenge, such as simulated brushing. In vitro pH cycling models are still widely used, since they simulate the dynamics of mineral loss and gain

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resulting from a cariogenic challenge condition involved in the formation of caries lesions, a situation that restorative materials are also subject to. The results obtained by these studies confirmed that a pH cycling regime can influence some surface properties of composite resins [14][15].

The growing demand of patients for aesthetic restorations, even in posterior areas, makes it necessary to conduct research to better understand the properties and applications of these materials submitted to challenging events. Considering that composite resin is commonly the material of choice for restorations of carious and non- carious lesions and that the wear and tear of areas free of occlusal contact is mainly due to the chemical and abrasion process and as the studies mentioned involve only conventional composite resins, this This study aims to evaluate the surface changes (surface roughness and microhardness) of conventional and Bulk Fill composite resins submitted to pH cycling and simulated brushing.

The hypotheses were that: 1) the pH cycling increases surface roughness and decreases the microhardness of composite resins; 2) and the simulated brushing structurally alters the surface of composite resins.

Materials and Methods

Three resin-based composites were used in this study: one conventional (Filtek Z250 XT - 3M ESPE, St Paulo, Minnesota, USA) and two bulk fill composites (Tetric N-Ceram bulk fill - Ivoclar Vivadent, Bendererstrasse, Schaan, Germany; Sonic Fill – Kerr Corporation, Orange, California, USA).

The table below (Table 1) shows the trade names, manufacturers, shade, abbreviation, matrix compositios, filler type, filler loading, increment thickness, polymerization time.

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Table 1- Resin-based composites specifications. Composite Resin Manufactur er (lot number) Shad e Abbreviatio n Matrix Composition

Filler type _Filler

loading (volum e%) Increm ent thickne ss (mm) Polymeriz ation time (s) Filtek Z250 XT 3M ESPE St Paulo, Minnesota, USA (LOT. 761671) A2 Z250 BIS-GMA UDMA BIS-EMA Zirconia/Si lica 60 2 20 Tetric N- Ceram Bulk Fill Ivoclar Vivadent, Bendererstra sse, Schaan, Germany (LOT. W83652) IVA (A2) TNC BIS-GMA UDMA BIS-EMA Barium aluminium silicate glass with two different mean particle sizes, an Isofiller, 61 4 20 ytterbium fluoride and spherical mixed oxide

SonicFill Kerr A2 SF EBADMA Silicon _83.5 ₄ ₂₀

Bulk Fill Corporation, Orange, California, USA (LOT. 6617848) BIS-GMA TEGDMA dioxide, barium glass

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Specimen preparation

Sixty speciments were prepared, 20 of each composite resin. For this, a round matrix (15mm wide x 4mm thickness) was used, measured by a caliper, filled composite resin z250 by the technique in increments and photoactivated each increment for 20 s, with wavelength 500mW / cm2 (VALO, Ultradent Product Inc ., South Jordan, UT, USA). Then a molding of the sample in heavy condensation silicone (Zetaplus- Zhermack). From this mold, Bulk Fill composite resin samples were prepared in a single increment and conventional composite resins in oblique increments of up to 2 mm. All samples were measured using a caliper.

When placing the increment in the mold, a teflon tape was placed in the upper area and the photopolymerizer was in direct contact. When removing the samples from the mold, was marked with a permanent pen on the bottom face, to differentiate the faces.

The specimens were subjected to standard grinding and planning in polishing machine (Arotec Ind. Com., Cotia,, SP, Brazil), the upper surface of each specimen was polished with a grain size of sanding discs ( #400, 600 e 1200) (CARBIMET Paper Discs; Buehler, IL, EUA), under constant cooling water. Soon after the use of each sandpaper, the specimens were taken to the ultrasound device (Marconi, Piracicaba, SP Brazil) with frequency of 40 KHz, for 5 minutes to remove possible abrasive granules that may interfere with the polishing quality of the next sandpaper or for the measurement of surface roughness.

Experimental Design

The samples were divided into six groups (n=10), two with Filtek Z250 resin, two with Tetric N-Ceram resin and two with SonicFill resin (Figure 1). All groups were initial analyzed to roughness and initial microhardness reading. After the readings, one group of each resin passed through the pH cycling, while the other groups were immersed in deionized water. After the cycling, a new roughness and microhardness reading was made in all groups and then passed through the simulated toothbrushing equipment. At the end of the brushing cycle, all groups passed the final roughness and microhardness reading.

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Figure 1. Representative scheme of the experimental design of this study.

*c: Groups that submit to pH cycling.

Measurement of surface roughness

The surface roughness readings were performed on 60 polished samples with rugosimeter (Surftest 211; Mitutoyo Corp., Tokyo, Japan). Each sample was individually fixed with utility wax on an acrylic base and planned, the measuring tip of the rugosimeter was positioned on the surface of the sample. The values of Ra (arithmetic mean of surface roughness) were measured using a cut-off of 0.25 mm at a speed of 0.05 mm/s. Three readings were taken on each surface at different positions, and the mean was calculated. Each reading was obtained after the sample was rotated by 120 °. Regions that presented some type of clear irregularity were disregarded.

The same method of measurement was repeated for the evaluation of the roughness (Ra) after pH cycling and simulated toothbrushing in the specimens that suffered the abrasion process, where the initial, partial and final roughness was

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obtained. The readings were performed exclusively in the area subjected to the abrasion procedure.

Measurement of surface microhardness (Knoop)

The surface microhardness of the specimens was determined using the microdurometer (HMV-S, Kyoto, Japan), with load of 25 g for 5 s. Three indentations were performed on the side to be subjected to the toothbrushing (test) of the specimens and the microhardness value was given through the average of the three edentations.

The same method of measurement was repeated for the evaluation of the partial and final microhardness in the specimens that underwent the pH cycling and abrasion process, where the difference among the initial, partial and final microhardnesses was obtained. The readings were performed exclusively in the area subjected to the abrasion procedure [16].

Storage of Specimens

After determination of surface roughness and initial microhardness, all specimens were individually stored in sealed, labeled bottles containing 5 ml of deionized water, kept at 37° C in a stove and 100% absolute humidity, simulating the condition found in the oral cavity.

A period of seven days was expected for the occurrence of water absorption and mass stability [17,18], property verified in the composite resins. Sequentially, the specimens were mopped with a tissue and the adhesive tape (3M) layer was applied to half of the upper surface area of each sample, which was maintained as a control, as protection [19.20].

pH Cycling

Ten specimens of each composite resin were subjected to pH cycling regimen prior to simulated toothbrushing procedure [21]. Each specimen was individually immersed in demineralising solution for 6 hours, consisting of 2.0 mM calcium and 2.0 mM phosphate in a 75 mM acetate buffer solution of pH 4.3 with 0.02% NaN3. After this time, the specimens were washed with deionized water, dried and immersed in remineralizing solution (artificial saliva) for 18 hours, consisting of 1.5 mM Ca; 0.9 mM PO4; 150 mM KCl in 20 mM Tris buffer pH 7.0 with 0.02% NaN 3,

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completing 24 hours. This protocol was strictly followed for 10 consecutive days, and at the end, the specimens were carefully washed in deionized water and stored in deionized water [22]. The pH of the solutions was monitored at the time of preparation through a pH meter.

Abrasion Procedure

A toothbrush simulation machine was used to perform the abrasion tests. The equipment consists of a motor that produces back and forth movements in ten arms, in which the "heads" of the toothbrushes were fixed with hot glue, enabling the simultaneous simulation of the brushing in ten specimens. In order to prevent them from moving during the back and forth movement, the equipment has a stainless steel bar with ten independent cavities for the positioning and stability of the specimens. The simulated toothbrushing procedure was performed with the Colgate Classic soft bristle toothbrush and Colgate MFP toothpaste (Colgate-Palmolive, Divisão da Kolynos Ltda, Osasco-SP, Brasil), wich was chosen because they are widely consumed on a large scale in domestic trade. The dentifrice composition has on calcium carbonate as abrasive agent and is classified as medium abrasiveness [22].

The heads of the dental brushes were coupled to the simulated brushing machine in such a way that the action of the dental brush bristles exerted friction on the surface of the specimen. Recalling that the half (control side) of the same specimen was protected with an insulation tape, allowing a clear identification between the brushed area and the control area. For the toothbrushing procedure, the groups were randomly selected and the specimens carefully embedded in the ten holes in the stainless steel bar of the equipment, approximately 1mm above this, ensuring intimate contact with rows of tufts of toothbrushes with the surface of each specimen wihth a 300g load. 0.4mL of solution (Toothpaste + deionized water) was added every 10 minutes in the proportions of 1: 2 by weight. The toothbrushes were changed at the end of every 50,000 cycles, and a total of 100,000 brush cycles were used for each specimen. The testing time for each group (100,000 cycles = 4,2 years) was approximately 8 hours. The surface roughness and microhardness readings were performed exclusively in the area subjected to the abrasion procedure [18].

After the toothbrushing cycles were completed, the specimens were carefully removed from the matrix and immediately rinsed in deionized tap water. The layer of tape applied as protection was removed with the aid of a clinical clamp. They

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were then placed inside an ultrasonic vibration apparatus for 5 minutes so that the abrasive particles of the toothpaste were removed from the surfaces of the samples. Following, were blotted dry and stored individually in identified sealed vials, containing 5 ml of deionized water. The vials were maintained at 37°C inside the oven and 100% absolute humidity, simulating the conditions found in the oral cavity.

Scanning Electron Microscope (SEM)

This step was performed representative using a Scanning Electron Microscope (SEM). For this, a specimen from each group was randomly selected to be metalized to allow its visualization in SEM. A photomicrograph with a 1000x magnification of each area was obtained: control and brushed, of each specimen.

Statistical Design

Data obtained from roughness and microhardness did not meet the normality criteria, according to the Shapiro-Wilk and Kolmogorov-Sminov normality tests and, therefore, the non-parametric Kruskal-Wallis statistical test was used to compare the groups with and without pH cycling within the times; and the same analysis for comparison between the evaluation times (α=5%).

Results

Surface roughness

Table 2 shows the median of initial roughness, partial (post-pH cycling) and final roughness (post-brushing). The Z250 and TNC groups, which were or were not subjected to pH cycling, in addition to the SF group without cycling did not have a significant increase in the surface roughness (p > 0.05), while the SF group submitted to the pH cycling obtained a significant increase (p = 0.031). All groups had a significant increase in surface roughness after brushing (p < 0.038). In the initial time, no group differed from the other statistically, but in the partial and final time all the groups that passed through the cycling differentiated between the groups that did not pass (p < 0.020).

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Table 2. Median initial, partial and final roughness (Ra) of specimens.

Group Cycling

Time

Baseline Partial Final

Without 0.071 (0.06; 0.09) Ba 0.079 (0.07; 0.10) Bbc (P=0,042) 0.145 (0.12; 0.18) Ac Z250

With 0.062 (0.06; 0.09) Ba 0.144 (0.02; 0.16) Ba (Paj=0,126) 0.230 (0.17; 0.37) Aab

TNC Without With 0.072 (0.06; 0.08) Ba 0.073 (0.06; 0.08) Ba 0.073 (0.01; 0.09) Bc (P=0,022) 0.141 (0.08; 0.17) Ba (Paj=0,067) 0.172 (0.13; 0.19) Abc 0.280 (0.21; 0.39) Aa Without 0.072 (0.07; 0.09) Ba 0.079 (0.06; 0.10) Bbc (P=0,010) 0.139 (0.11; 0.16) Ac SF

With 0.074 (0.07; 0.08) Ca 0.134 (0.13; 0.16) Bab (Paj=0,031) 0.176 (0.15; 0.20) Aabc Median values followed by distinct letters differ statistically at 5%, according to Kruskal-Wallis test. Uppercase letters compare different time evaluation within resin composite group (lines). Lowercase letters compare resin composite with or without pH Cycling (columns). N=10 specimens/group.

Microhardness

Table 3 shows the mean values of the initial, partial (post pH cycling) and final (post-brushing) microhardness. The groups Z250 and SF that did not undergo pH cycling had no significant difference in surface microhardness between all the evaluation times (p > 0.05), but all groups that passed through the pH cycling of these composite resins, besides the TNC groups, obtained a significant decrease on surface microhardness (p < 0.007), but did not change after brushing (p > 0.05). In all times, Z250 and TNC groups differed statistically from each other (p < 0.001), but similar to SF group (p > 0.05).

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Table 3. Superficial microhardness (KHN) median values of the groups in different time.

Group Cycling

Time

Baseline Partial Final

Without 101.5 (97.4; 107.0) Aa 102.0 (96.8; 106.0) Aa 99.5 (93.5; 102.0) Aa Z250

With 100.0 (99.1; 109.0) Aa 91.4 (87.8; 96.1) Bab 90.4 (87.3; 100.0) Bab

TNC

Without 68.2 (67.7; 69.8) Ab 51.2 (45.3; 54.5) Bc 53.0 (51.2; 54.6) Bc With 68.9 (67.9; 69.4) Ab 53.5 (51.2; 57.7) Bc 53.5 (49.2; 56.5) Bc Without 86.6 (82.7; 86.9) Aab 86.6 (82.3; 87.6) Aabc 87.3 (71.4; 91.0) Aab SF

With 86.4 (82.6; 86.9) Aab 68.2 (62.2; 71.3) Bbc 69.0 (66.1; 82.8) Bbc Median values followed by distinct letters differ statistically at 5%, according to Kruskal-Wallis test. Uppercase letters compare different time evaluation within resin composite group (lines). Lowercase letters compare resin composite with or without pH Cycling (columns). N=10 specimens/group.

Scanning Electron Microscope (SEM)

SEM representative images of composite resin surface after simulates brushing. Figure 2 represents the composite resin Z250, where A and B represents a specimen without pH cycling and C and D with pH cycling. Image B and D were exposed during the experiment and side A and C were isolated with tape during the entire experiment, being removed after the simulated brushing. The exposed side (B, D) has a more irregular surface than the isolated side (A, C). Images B and D are visually similar. Figure 3 represents TNC composite resin, where A and B represents a specimen without pH cycling and C and D with pH cycling. Image B and D were exposed during the experiment and side A and C were isolated with tape during the entire experiment, being removed after the simulated brushing. The exposed side (B, D) has a more irregular surface than the isolated side (A, C). Images B and D are visually similar. Figure 4 represents SF composite resin, where A and B represents a specimen without pH cycling and C and D has with pH cycling. Image B and D were exposed during the experiment and side A and C were isolated with tape during the entire experiment, being removed after the simulated brushing. The exposed side (B, D) has a more

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27 LADO ISOLADO S/ CICLAGEM LADO ESCOVADO S/ CICLAGEM LADO ISOLADO COM CICLAGEM LADO ESCOVADO COM CICLAGEM LADO ISOLADO S/ CICLAGEM LADO ESCOVADO S/ CICLAGEM LADO ISOLADO COM CICLAGEM LADO ESCOVADO COM CICLAGEM

irregular surface than the isolated side (A, C). Image D has more irregular surface than B.

Figure 2. SEM representative images of composite resin surface (Z250) A- Z250 group

without side cycling isolated. B- Group Z250 without exposed side cycling. C- Group Z250 with side cycling isolated. D- Group Z250 with exposed side cycling.

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LADO ISOLADO S/ CICLAGEM LADO ESCOVADO S/ CICLAGEM LADO ISOLADO COM CICLAGEM LADO ESCOVADO COM CICLAGEM

Figure 3. SEM representative images of composite resin surface (Tetric N-Ceram) A-

TNC group without side cycling isolated. B- TNC group without exposed side cycling. C- TNC group with isolated side cycling. D- TNC group with exposed side cycling.

Figure 4. SEM representative images of composite resin surface (Sonic Fill) A- SF

group without side cycling isolated. B- Group SF without cycling exposed side. C- SF group with isolated side cycling. D- Group SF with exposed side cycling.

Discussion

For this in vitro study, pH cycling was used in order to address the clinical reality with the challenges present in the oral cavity. From the results on the microhardness of the composite resins, the influence of the pH cycle on the surface morphology was decisive, which was not essential to cause changes in the surface roughness of all the tested resins, since only the SF obtained an increase in statistically significant roughness after pH cycling. Thus, the first hypothesis of the present study was rejected. The widespread use of resin-based restorative materials and their exposure to adverse conditions in the oral environment require that they be resistant to morphological changes [24]. However, under conditions of the oral environment, restorative materials, including composite resins analyzed in this study, may undergo

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degradation over time, which can be predicted by changes in microhardness and surface roughness [25,26].

Many polymers used in dentistry, such as composite resins, complete dentures and protective bases, are susceptible to the absorption of solvents, mainly to water and the loss of soluble components [27,28]. The solvent molecule forces the polymer chains to separate, causing expansion. As the cohesive resilience decreases, the polymer becomes less hard, the glass transition temperature is reduced and the strength can be decreased. This justifies the decrease in the microhardness of the Tetric resin that was not subjected to pH cycling [28,29].

The composite resins still have limitations, mainly in relation to the maintenance of physical and morphological properties over time. Composite resin restorations receive a continuous load during chewing and this stress on the material causes wear of the posterior restorations. However, the intensity of wear depends on the mechanical load, type of composite resin and surface properties [9]. In this study, the components EBADMA, BIS-GMA and TEGDMA in the matrix represented by the SF resin showed a statistically significant increase in surface roughness after the passage of the pH cycle. While the groups with organic matrix BIS-GMA, UDMA and BIS-EMA (TNC and Z250), did not show statistically significant changes after cycling. These results are in line with those of a previous study [31], which analyzed changes in the surface micromorphology of various resin-based materials subjected to a pH cycling regime. This study [31] showed several filling particles protruding from the surface of a micro-load composite, which was attributed to the degradation of the polymeric matrix. In addition, the polymeric matrix of a hybrid composite and a modified polyacid composite resin exhibited several gaps, which were associated with possible degradation of the surrounding resin matrix or silane coupling agent and loss of charge particles [31 ].

The roughness of composite resins and any other restorative material is changed after polishing due to several factors present in the oral cavity and which act on the materials, such as abrasion processes against brushing or by the action of food and the friction of antagonistic teeth [18] Thus, all composite resins that underwent the simulated brushing process did not show statistically altered microhardness, but the roughness increased as a whole, regardless of the organic matrix. It can be seen in the images made by SEM, in which the simulated brushing side has an irregular surface,

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compared to the isolated side. Therefore, the second hypothesis that simulated brushing structurally alters the surface of composite resins was accepted.

This loss of structure of composite resins leads to loss of anatomy of restorations, which can result in problems: occlusal, proximal contacts, aesthetics, marginal infiltration, loss of VOD, loss of smoothness and shine, staining, greater accumulation of biofilm [10]. The wear of the organic matrix caused by the friction of tooth bristles with dentifrice causes the exposure of inorganic particles and the loss of charge particles [32]. The simulated brushing tests are performed at the organic matrix, filling particles or matrix / filling interface, associated with the cariogenic challenge conditions, the acid pH is established, leading to a decrease in wear resistance due to the abrasion test [33]. With the exception of the SF group, the groups that underwent pH cycling did not have an increase in roughness in half a period, but after brushing the groups that underwent cycling were the most "statistically significant" impaired compared to the groups that did not. That is, the association of pH cycling with simulated brushing abrasion leaves the surface more vulnerable to "degradation", producing surface changes in relation to roughness and microhardness for Bulk Fill and conventional resins, therefore, it presents higher values of roughness the surface.

Conclusion

From the experimental conditions adopted in this study, it can be concluded that a pH cycle was harmful in relation to the microhardness of resinous materials, in addition, a simulated brushing generated greater changes in surface roughness. Among the resins tested, the Bulk Fill resins results endings similar to conventional resin.

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[9] TABATABAEI M. H., ARAMI S., FARAHT F. Effect of Mechanical Loads and Surface Roughness on Wear of Silorane and Methacrylate-Based Posterior Composites. J Dent (Tehran). 2016 Nov;13(6):407-414.

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[12] XAVIER A. M., SUNNY S. M., RAI K., HEGDE A. M. Repeated exposure of acidic beverages on esthetic restorative materials: An in-vitro surface microhardness study. J Clin Exp Dent. 2016 Jul 1;8(3):e312-7. doi: 10.4317/jced.52906. eCollection 2016 Jul.

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[13] GHAVAMI-LAHIJI M., HOOSHMAND T. Analytical methods for the

measurement of polymerization kinetics and stresses of dental resin-based composites: A review. Dent Res J (Isfahan). 2017 Jul-Aug;14(4):225-240.

[14] ISHIKIRIAMA S. K., DE OLIVEIRA G. U., MAENOSONO R. M., WANG L., DUARTE M. A., MONDELLI R. F. Wear and surface roughness of silorane composites after pH cyclihng and toothbrushing abrasion. Am J Dent. 2014 Aug;27(4):195-8. [15] RAO B. S., MOOSANI G. K., SHANMUGARAI M. KANNAPAN B.,

SHANKAR B. S., ISMAIL P. M. Fluoride release and uptake of five dental restoratives from mouthwashes and dentifrices. J Int Oral Health. 2015 Jan;7(1):1-5.

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[18] WANG L., GARCIA F.C.P., ARAÚJO P.A., FRANCO E.B., MONDELLI R.F.L. Wear resistance of packable resin composite after simulated toothbrushing test. J Esthet Rest Dent. 2004;16(5):303-15.

[19] FRANCISCONI L.F., HONÓRIO H.M., RIOS D., MAGALHÃES A.C., MACHADO M.A.A.M., BUZALAF M.A.R. Effect of erosive pH cycling on differente restorative materials and on enamel restored with these materials. Oper Dent. 2008;33(2):203-8.

[20] RIOS D., HONÓRIO H.M., FRANCISCONI L.F., MAGALHÃES A.C., MACHADO M.A.A.M., BUZALAF .M.A.R.B. In situ effect of an erosive challenge on different restorative materials and on enamel adjacent to these materials. J Dent. 2008;36(2):152-7.

[21] SERRA M.C., CURY J.A. The in vitro effect of glass-ionomer cement restoration on enamel subjected to a demineralization and remineralization model. Quintessence Int. 1992; 23(2):143-7

[22] PRAKKI A., ARAÚJO P.A., NAVARRO M.F.L., MONDELLI J., MONDELLI R.F.L. Effect of toothbrushing abrasion on weight and surface roughness of pH-cycled resin cements and indirect restorative materials. Quintessence Int. 2007;38(9):e544-54

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[24] BAGHERI R., TYAS M.J., BURROW M.F. Comparison of the effect of storage media on hardness and shear punch strength of tooth-colored restorative materials. Am J Dent. 2007 Oct;20(5):329-34.

[25] JAEGGI T., GRUNINGER A., LUSSI A. Dental erosion. Monogr Oral Sci. 2006;20:200-14.

[26] SILVA R.C., ZUANNON A.C.C. Surface roughness of glass ionomer cements indicated for atraumatic restorative treatment. Braz Dent J. 2006;17:106-9.

[27] BROWNING, W.D.; DENNISON, J.B. A survey of failure modes in composite resin restorations. Oper. Dent. , Seattle 1996, v.21, n.4, p.160-166, July/Aug.

[28] BURKE F.J., WILSON N.H., CHEUNG S.W., MJÖR I.A. Influence of patient factors on age of restorations at failure and reasons for theis placement and replacement. J Dent. 2001 Jul;29(5):317-24.

[29] ORTEGREN U.O., WELLENDORF H., KARLSSON S, RUYTTER I.E. Water sorption and solubility of dental composites and identification of monomers released in an aqueous environment. J Oral Rehabil 2001;28:1106-15.

[30] VAN NOORT, R. Introdução aos materiais dentários. 2.ed. Porto Alegre: Artmed, 2004

Bagheri R, Tyas MJ, Burrow MF. Subsurface degradation of resin-based composites. Dent Mater. 2007;23:944-51.

[31] TURSSI C.P., HARA A.T., SERRA M.C., RODRIGUES A.L. Jr. Effect of storage media upon the surface micromorphology of resin-based restorative materials. J Oral Rehabil. 2002;29:864-71.

[32] O'BRIEN W.J., YEE JR. J. Microstructure of posterior restorations of composite resin after clinical wear. Oper Dent. 1980;5:90-4.

[33] ATTIN T., BUCHALLA W., TRETT A., HELLWING E. Toothbrushing abrasion of polyacid-modified composites in neutral and acid buffer solutions. J Prosthet Dent. 1998; 80:148-50

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3 CONCLUSÃO

Das condições experimentais adotadas neste estudo, pode-se concluir que, a ciclagem de pH foi deletéria em relação a microdureza dos materiais resinosos, contudo, a escovação simulada gerou maiores alterações de rugosidade superficial.Dentre as resinas testadas, as resinas Bulk Fill apresentaram resultados semelhantes a resina convencional.

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Referências*

Abbasi M, Moradi Z, Mirzaei M, Kharazifard MJ, Reazaei S. Polymerization Shrinkage of Five Bulk-Fill Composite Resins in Comparison with a Conventional Composite Resin. J Dent (Tehran) 2018 Nov;15(6):365-374.

Alqahtani MQ, Michaud PL, Sullivan B, Labrie D, Alshaafi MM, Price RB. Effect of high irradiance on depth of cure of a conventional and a bulk fill resin-based composite. Oper Dent. 2015;40(6):662–672.

Benetti AR, Havndrup-Pedersen C, Honoré D, Pedersen M K, Pallesen U. Bulk-Fill resin composites: polymerization contraction, depth of cure, and gap formation. Oper Dent. 2015 Mar-Apr;40(2):190-200. doi: 10.2341/13-324-L..

Chesterman J, Jowett A, Gallacher A, Nixon P. Bulk-fill resin-based composite restorative materials: a review. Br Dent J. 2017 Mar 10;222(5):337-344. doi: 10.1038/sj.bdj.2017.214.

Dalla-Vecchia KB, Taborda TD, Stona D, Pressi H, Burnett Júnior L H, Rodrigues Júniuor S A. Influence of polishing on surface roughness following toothbrushing wear of composite resins. Gen Dent. 2017 Jan-Feb;65(1):68-74.

Ghavami-Lahiji M, Hooshmand T. Analytical methods for the measurement of polymerization kinetics and stresses of dental resin-based composites: A review. Dent Res J (Isfahan). 2017 Jul-Aug;14(4):225-240.

Heintze S D, Reichl F. X., Hickel R. Wear of dental materials: Clinical significance and laboratory wear simulation methods –A review. Dent Mater J. 2019 Mar 26. doi: 10.4012/dmj.2018-140.Ishikiriama SK, de Oliveira GU, Maenosono RM, Wang L, Duarte MA, Mondelli RF. Wear and surface roughness of silorane composites after pH cyclihng and toothbrushing abrasion. Am J Dent. 2014 Aug;27(4):195-8.

Langalia A, Buch A, Khamar M, Patel P. Polymerization shrinkage of composite resins: a review. J Med Dent Sci Res. 2015. October; 2(10): 23– 7.

Lins RBE, Aristildes., Osório JH, Cordeiro CMB, Yanikian CRF, Bicalho AA, Stape THS, Soares CJ, Martins LRM. Biomechanical behaviour of bulk-fill resin composites in class II restorations. J Mech Behav Biomed Mater. 2019 Jul 2;98:255-261. doi: 10.1016/j.jmbbm.2019.06.032.

Pereira R, Giorgi MCC, Lins RBE, Theobaldo JD, Lima DANL, Marchi GM, Aguiar FHB Physical and photoelastic properties of bulk-fill and conventional composites. Clin Cosmet Investig Dent. 2018 Dec 12;10:287-296. doi: 10.2147/CCIDE.S184660.

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*De acordo com as normal da UNICAMP/FOP, baseada nas padronizaçõesdo International Committe of Medical Journal Editors – Vancouver Group. Abreviatura dos periódicos em conformidade com o PubMed

Rao B S, Moosani GK, Shanmugarai M, Kannapan B, Shankar B S, Ismail PM. Fluoride release and uptake of five dental restoratives from mouthwashes and dentifrices. J Int Oral Health. 2015 Jan;7(1):1-5.

Tabatabaei MH, Arami S, Faraht F. Effect of Mechanical Loads and Surface Roughness on Wear of Silorane and Methacrylate-Based Posterior Composites. J Dent (Tehran). 2016 Nov;13(6):407-414.

Tsujimoto A, Barkmeier WW, Fischer NG, Nojiri K, Nagura Y, Takamizawa T, Latta MA, Mjazaki M. Wear of resin composites: Current insights into underlying mechanisms, evaluation methods and influential factors. Jpn Dent Sci Rev. May;54(2):76-87. doi: 10.1016/j.jdsr.2017.11.002.

Xavier A. M., Sunny S. M., Rai K., Hegde A. M. Repeated exposure of acidic beverages on esthetic restorative materials: An in-vitro surface microhardness study. J Clin Exp Dent. 2016 Jul 1;8(3):e312-7. doi: 10.4317/jced.52906. eCollection 2016 Jul.

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APÊNDICE I - Metodologia Ilustrativa

Figura 1. Preparo das amostras. A) Confecção de matriz metálica circular

(15x4mm), mensurada por um paquímetro; B) Preenchimento da matriz com resina composta; C) Fotopolimerização; D) Espécime modelo finalizado; E) Espécime modelo fora da matriz metálica e comas bosdar regularizadas por uma soflex; F) Moldagem com silicone de condensação pesado (Zetaplus-Zhermack); G) Preenchimento do molde com resina composta; H) Fotopolimerização; I) Espécime confeccionado.

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Figura 2. Ciclagem de pH. A) Isolamento com fita isolante vermelha na metade

da área de cada espécime; B) Fixação de uma haste metálica com cera utilidade; C) Imersão dos espécimes em solução desmineralizadora; D) Imersão dos espécimes em solução remineralizadora; E) Imersão dos espécimes em água deionizada; F) Lavagem dos espécimes em água deionizada.

Figura 3. A) Fixação dos espécimes com cola quente em uma base a ser inserida

no equipamento de escovação simulada; B) Dentifrício de MFP utilizado e cabeça removida da escova dental para fixação com cola quente no equipamento; C) Equipamento de escovação simulada.

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ANEXO I – Comprovante de Submissão

Dear Miss Orlando,

Your submission entitled "COMPARISON OF PH CYCLING EFFECT AND SIMULATED TOOTHBRUSHING ON CONVENTIONAL AND BULK FILL COMPOSITE RESIN SURFACE." has been assigned the following manuscript

number: JJOD-D-20-00099.

You will be able to check on the progress of your paper by logging on to the Elsevier Editorial System as an author.

The URL is https://ees.elsevier.com/jjod/.

Thank you for submitting your work to this journal.

Kind regards,

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ANEXO II – Relatório de similaridade

Turnitin Relatório de Originalidade

 Processado em: 31-mar-2020 11:57 -03

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 Contagem de Palavras: 8831

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COMPARAÇÃO DO EFEITO DA CICLAGEM DE PH E ESCO... Por Luis Martins

Índice de Semelhança 30%

Semelhança por Fonte Internet Sources: 25% Publicações: 22% Documentos de Aluno: 17%

3% match (Internet a partir de 09-nov-2019)

https://teses.usp.br/teses/disponiveis/25/25148/tde-18012012- 144442/publico/GabrielaUlianOliveira_Rev.pdf

2% match (Internet a partir de 31-dez-2016)

https://pdfs.semanticscholar.org/4e8a/73b7241486ca6a43dfb472e6aee7b2d28bbe.pdf

2% match (Internet a partir de 13-mai-2019)

http://repositorio.unicamp.br

1% match (Internet a partir de 20-nov-2012)

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41

1% match (Internet a partir de 05-fev-2020)

https://www.nature.com/articles/sj.bdj.2011.430?code=cdc8f536-ea0f-4f6e-9f3c- f4c5091f1632&error=cookies_not_supported

<1% match (Internet a partir de 20-set-2019)

<1% match (Internet a partir de 21-set-2019) http://repositorio.unicamp.br

<1% match (Internet a partir de 17-jan-2019)

http://www.rae.gr

<1% match (Internet a partir de 20-out-2018)

https://www.cambridge.org/core/journals/microscopy-and-microanalysis/article/micro- energydispersive-xray-fluoresence-mapping-of-enamel-and-dental-materials-after- chemical-erosion/A0AC768E07E989A23DF3EA2887812932

<1% match (Internet a partir de 26-jun-2019)

https://www.aulavirtualusmp.pe/ojs/index.php/Rev-Kiru0/article/view/1227

<1% match (documentos dos alunos a partir de 06-dez-2019) Submitted to Brigham Young University on 2019-12-06

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I. Patrascu, E. Vasilescu, E. Gatin, R.R. Cara-Ilici. "Chapter 26 Corrosion of Biomaterials Used in Dental Reconstruction Dentistry", IntechOpen, 2014

<1% match (Internet a partir de 07-mar-2020)

https://worldwidescience.org/topicpages/a/acp+resin+composites.html

<1% match (Internet a partir de 06-dez-2017)

https://repositorio.unesp.br/bitstream/handle/11449/145489/000848141.pdf?isAllowed= y&sequence=1

<1% match (publicações)

ISHIKIRIAMA, Sérgio Kiyoshi, Juan Fernando ORDOÑÉZ-AGUILERA, Rafael Massunari MAENOSONO, Fernanda Lessa Amaral VOLÚ, and Rafael Francisco Lia MONDELLI. "Surface roughness and wear of resin cements after toothbrush abrasion", Brazilian Oral Research, 2015.

<1% match (documentos dos alunos a partir de 21-jun-2019)

Submitted to University of Modena and Reggio Emilia on 2019-06-21

https://www.dovepress.com/physical-and-photoelastic-properties-of-bulk-fill-and- conventional-com-peer-reviewed-fulltext-article-CCIDE

https://www.mdpi.com/1996-1944/13/5/1028/htm

https://www.mdpi.com/2073-4360/12/1/223/html

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Diego Felipe Mardegan Gonçalves, André Luiz Fraga Briso, Nubia Inocencya Pavesi Pini, Mariana Dias Moda et al. "Effects of dentifrices on mechanical resistance of dentin and restorative materials after erosion and abrasion", Journal of the Mechanical

Behavior of Biomedical Materials, 2019

Thiago Isidro Vieira, Adílis Kalina Alexandria, Tatiana Kelly da Silva Fidalgo, Aline de Almeida Neves et al. "Chemical and Physical Modification of Carbonated Energy Beverages to Reduce the Damage Over Teeth and Restorative Materials", Elsevier BV, 2019

<1% match (documentos dos alunos a partir de 30-ago-2016)

Submitted to University College London on 2016-08-30

<1% match (Internet a partir de 03-jun-2017) http://mdpi.com

http://www.labome.org

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https://worldwidescience.org/topicpages/t/tooth+wear+evaluated.html

<1% match (Internet a partir de 18-ago-2016) http://www.medicinaoral.com

<1% match (Internet a partir de 12-mar-2017) http://ns2.quintpub.com

https://www.mdpi.com/2304-6767/6/4/55/html

Leticia Cristina Cidreira Boaro, Diana Pereira Lopes, Andréia Santos Caetano de Souza, Ellea Lie Nakano et al. "Clinical performance and chemical-physical properties of bulk fill composites resin —a systematic review and meta-analysis", Dental Materials, 2019

<1% match (Internet a partir de 10-fev-2018)

http://bv.fapesp.br

Martin Rosentritt, Andreas Koenig, Carola Kolbeck, Stephanie Krifka, Sebastian Hahnel. "Validating laboratory simulation with resin-based materials for temporary fixed denture prostheses – Results from clinical and laboratory trials", Journal of the Mechanical Behavior of Biomedical Materials, 2020

"Brazilian Society for Dental Research 17th Annual Meeting September 2-6, 2000 Aguas de Lindoa, Brazil", Journal of Dental Research, 04/01/2001

http://nursingworld.org

Terence E. Donovan, Riccardo Marzola, Kevin R. Murphy, David R. Cagna et al. "Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry", The Journal of Prosthetic Dentistry, 2018

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"Full Issue PDF", Operative Dentistry, 2016

Matheus Kury, Carolina Perches, Daylana P. Silva, Carolina B. André et al. "Color change, diffusion of hydrogen peroxide, and enamel morphology after in‐office bleaching with violet light or nonthermal atmospheric plasma: An in vitro study", Journal of Esthetic and Restorative Dentistry, 2019

Thayla Hellen Nunes Gouveia, Juliana do Carmo Públio, Glaucia Maria Bovi

Ambrosano, Luís Alexandre Maffei Sartini Paulillo et al. "Effect of at-home bleaching with different thickeners and aging on physical properties of a nanocomposite",

European Journal of Dentistry, 2019

<1% match (Internet a partir de 12-ago-2019)

"Modern Operative Dentistry", Springer Science and Business Media LLC, 2020

Farzin Heravi, Hossein Bagheri, Abdolrasoul Rangrazi, Seyed Mojtaba Zebarjad.

"Incorporation of CPP-ACP into Luting and Lining GIC: Influence on Wear Rate (in the Presence of Artificial Saliva) and Compressive Strength", ACS Biomaterials Science & Engineering, 2016

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http://www.robrac.org.br

Sarrett, D.C.. "Clinical challenges and the relevance of materials testing for posterior composite restorations", Dental Materials, 200501

Lauber Jose dos Santos Almeida Junior, Estevam Carlos de Oliveira Lula, Karla Janilee de Souza Penha, Vinicius Souza Correia et al. "Polymerization Shrinkage of Bulk Fill Composites and its Correlation with Bond Strength", Brazilian Dental Journal, 2018 <1% match (Internet a partir de 09-set-2019)

https://www.karger.com/Article/FullText/493099 <1% match (Internet a partir de 30-mar-2020) https://jopdentonline.org/doi/full/10.2341/19-012-L <1% match (publicações)

http://sbpqo.org.br

Caroline Dini, Bruna E. Nagay, Jairo M. Cordeiro, Nilson C. da Cruz et al. "UV- photofunctionalization of a biomimetic coating for dental implants application", Materials Science and Engineering: C, 2020