UNIVERSIDADE FEDERAL FLUMINENSE FACULDADE DE ODONTOLOGIA
AVALIAÇÃO DA RUGOSIDADE NA SUPERFÍCIE DA ZIRCÔNIA, PRODUZIDA COM O JATEAMENTO DE ÓXIDO DE ALUMÍNIO E COM OS LASERS ERBIUM- YAG, NEODYMIUM-DOPED-YAG E CO2: UMA REVISÃO SISTEMÁTICA COM
META-ANÁLISE
Niterói 2017
UNIVERSIDADE FEDERAL FLUMINENSE FACULDADE DE ODONTOLOGIA
AVALIAÇÃO DA RUGOSIDADE NA SUPERFÍCIE DA ZIRCÔNIA, PRODUZIDA COM O JATEAMENTO DE ÓXIDO DE ALUMÍNIO E COM OS LASERS ERBIUM- YAG, NEODYMIUM-DOPED-YAG E CO2: UMA REVISÃO SISTEMÁTICA COM
META-ANÁLISE
FELIPE VILLELA MARTINS Dissertação apresentada à Faculdade de Odontologia da Universidade Federal Fluminense, como parte dos requisitos para obtenção do título de Mestre, pelo Programa de Pós-Graduação em Odontologia.
Área de Concentração: Odontologia
Orientador: Prof. Dr. EDGARD DE MELLO FONSECA
Niterói 2017
BANCA EXAMINADORA
Prof. Dr. EDGARD DE MELLO FONSECA CPF: 011.675.757-11 Instituição: UNIVERSIDADE FEDERAL FLUMINENSE
Decisão: _________________________Assinatura: ________________________
Prof(a). Dr(a). JAIME NORONHA CPF: 087.979.067.94 Instituição: UNIVERSIDADE FEDERAL FLUMINENSE
Decisão: _________________________Assinatura: ________________________
Prof. Dr. Ronaldo Barcellos de Santana CPF: 032.158.677-88 Instituição: UNIVERSIDADE FEDERAL FLUMINENSE
Decisão: _________________________Assinatura: ________________________
Prof. Dr. Rafael Ferrone Andreiuolo CPF: 081.947.817-28 Instituição: UNIVERSIDADE FEDERAL DO RIO DE JANEIRO
Decisão: _________________________Assinatura: ________________________
AGRADECIMENTOS
Agradeço ao Programa de Pós-Graduação da Universidade Federal Fluminense - UFF pela oportunidade da realização do Mestrado em Clínica Odontológica.
Ao meu orientador Professor Dr. Edgard de Mello Fonseca pelo conhecimento, dedicação e confiança como fatores fundamentais a realização deste trabalho.
A Professora Dra. Cláudia Trindade por toda sua atenção, dedicação e empenho que me dispensou no decorrer do período deste trabalho.
Aos docentes do Programa de Pós-Graduação em Odontologia que me ensinaram e muito contribuíram para o conhecimento e evolução das pesquisas como peças fundamentais do trabalho do Curso de Mestrado.
.
RESUMO
Martins FV. Avaliação da rugosidade na superfície da zircônia, produzida com o jateamento de óxido de alumínio e com os lasers Erbium-YAG, Neodymium-Doped- YAG e CO2. Uma Revisão Sistemática com Meta-Análise [dissertação]. Niterói:
Universidade Federal Fluminense, Faculdade de Odontologia; 2017.
O sucesso clínico e a confiabilidade de um sistema cerâmico estão diretamente ligados à integridade mecânica dos materiais e à resistência da união nas interfaces:
ceramo-cerâmica ou cerâmica-adesivo. A fratura adesiva, também chamada de delaminação e a decimentação da peça protética, tem se mostrado como as falhas mais frequentes nas restaurações que utilizam a zircônia como infraestrutura. Com o objetivo de aumentar a força da união na interface, alguns autores propõem que seja feito um tratamento para aumentar a rugosidade na superficie da zircônia. Diferentes tipos de laser e jateamento com óxido de alumínio tem sido utilizados em pesquisas in-vitro, mas até o presente momento os resultados encontrados são divergentes. O objetivo desta Meta-Análise foi avaliar os resultados da rugosidade média na superfície da zircônia produzida com o jateamento de óxido de alumínio e com os lasers Erbium-YAG, Neodymium-Doped-YAG e CO2. Este estudo foi realizado de acordo com o PRISMA checklist. O processo PICO foi usado para desenvolver as estratégias de busca. A pesquisa bibliográfica foi realizada para identificar os artigos relevantes até abril de 2017 nas bases de buscas: MEDLINE via PubMed; Web of Science e Scopus . Os estudos selecionados foram submetidos à avaliação do risco de viés. Na meta-análise foram avaliados os dados das rugosidades médias, o desvio padrão do grupo experimental e, posteriormente, comparados com o grupo controle sem o tratamento da superfície. As análises foram realizadas no Review Manager Software versão 5.3. Dos 2724 estudos potencialmente elegíveis, 17 preencheram todos os critérios de inclusão e apresentaram risco de viés médio. Na análise global e por subgrupos, foi constatado que há diferença estatística (p ≤ 0,05) favorecendo os grupos experimentais. Os valores dos testes de I² foram maiores que 90%
representando a alta heterogeneidade entre os estudos. Os corpos de prova pré- sinterizados submetidos ao jateamento, apresentaram maior rugosidade superficial se comparados ao jateamento após o processo de sinterização. Esta modificação possibilitou evitar a transformação da fase tetragonal para a fase monoclínica. Os
resultados indicaram que o laser de Nd:YAG e CO2 formaram microfissuras superficiais. O laser de Erbium utilizado com menor intensidade de energia se apresenta como um método promissor para o tratamento superficial da zircônia.
Keywords: Zircônia; jateamento; óxido de alumínio; laser; tratamento de superfície; rugosidade
ABSTRACT
Martins FV. Evaluation of the roughness on the zirconia surface produced with the aluminum oxide sand blasting and the Erbium-YAG, Neodymium-Doped-YAG or CO2 lasers: A systematic review and meta-analysis. [dissertation]. Niterói: Universidade Federal Fluminense, Faculdade de Odontologia; 2017.
The clinical success and reliability of the ceramic system are directly related to the mechanical integrity of the materials and the bond strength at the interface. Adhesive fracture, also called delamination, and the decementation of the prosthetic crown, has been shown to be the most frequent failure in restorations using zirconia as an infrastructure. In order to increase the bond strength at the interface, some authors propose a treatment to increase the zirconia surface roughness. In laboratory studies, different types of laser and sand blasting with aluminum oxide have been applied.
However, up to the present time, the studies performed presented divergent results.
Different types of laser and sand blasting with aluminum oxide have been used in in-vitro research, but up to the present time the results found are divergent. The objective of this Meta-Analysis was to evaluate the results of the average roughness on the Y-TZP zirconia surface, produced with the aluminum oxide sand blasting and the Erbium-YAG, Neodymium-Doped-YAG or CO2 lasers. This study was performed according to the PRISMA checklist. The PICO process was used to develop search strategies. The bibliographic research was carried out to identify the relevant articles until April 2017 in the search bases: MEDLINE via PubMed; Web of Science and Scopus. The selected studies were submitted to bias risk assessment. In the meta-analysis were evaluated the data of the roughness mean, the standard deviation of the experimental group and compared with the control group without the surface treatment. The analyzes were performed in Review Manager Software version 5.3. Of the 2724 potentially eligible studies, 17 met all inclusion criteria and presented an medium risk of bias. In the global analysis and by subgroups, it was found that there is statistical difference (p ≤ 0.05) favoring the experimental groups. The I² test values were greater than 90% representing
the high heterogeneity among the studies. The pre-sintered specimens submitted to sand blasting had higher surface roughness compared to sand blasting after the sintering process. This modification made it possible to avoid the transformation of the tetragonal phase into the monoclinic phase. The results indicated that the Nd: YAG and CO2 laser formed superficial microcracks. The Erbium laser used with lower energy intensity is presented as a promising method for surface treatment of zirconia.
Keywords: Zirconia; sandblast; aluminum oxide; laser; surface treatment;
roughness
1 – INTRODUÇÃO
A zircônia é uma cerâmica policristalina que possui três formas cristalográficas:
monoclínica, tetragonal e cúbica. 1,2 Sua utilização na Odontologia se tornou possível a partir da adição de componentes como o cálcio, magnésio, ítria ou céria que, em temperatura ambiente, estabilizam a fase tetragonal metaestável. 2 Quando a zircônia é submetida a fatores termomecânicos, ocorre a transformação da sua fase tetragonal para a monoclínica e pode ser observado o aumento de aproximadamente 4% no volume dos seus grãos. 2,3 Este fenômeno é chamado de tenacificação e é o responsável pela sua elevada resistência à fratura quando comparada a outras cerâmicas. 3,4 Assim, por conta deste fenômeno, a zircônia usinada com o sistema CAD/CAM passou a ser utilizada na confecção de infraestruturas para próteses parciais fixas. 4-6
O sucesso clínico e a confiabilidade de um sistema cerâmico estão diretamente ligados à integridade mecânica dos materiais e a resistência da união na interfaces:
ceramo-cerâmica ou cerâmica-adesivo. 7-9 A fratura adesiva, também chamada de delaminação, e a decimentação da peça protética, tem se mostrado como a falha mais frequente em restaurações que utilizam zircônia como infraestrutura. 10-15 Isto porque suas propriedades físicas diferem das cerâmicas a base de sílica. 7-9,16,17 A ausência da fase vítrea e do dióxido de silício, torna a zircônia resistente ao ácido fluorídrico e não suscetível à silanização. 14-16 Por esta razão, é necessária uma nova estratégia para aumentar a força da união na interface. Alguns autores propõem que seja feito um tratamento para aumentar a rugosidade na superficie da zircônia e, assim, criar o interlock micromecânico. 3
A zircônia pode ser pigmentada para uma melhor caracterização. Ainda assim, se apresenta opaca quando comparada a outras cerâmicas dentárias.2 Desta forma, se faz necessário seu revestimento com um material altamente translúcido a fim de melhorar suas caracteristicas ópticas responsáveis pela estética da restauração.2,5 Porém, a fragilidade deste sistema cerâmico pode levar a uma falha prematura, principalmente na dentição posterior onde a carga oclusal é mais elevada.2,5,6 Falhas de união na área crítica tem levado a atenção dos pesquisadores a possíveis fatores causais, tais como: o
coeficiente de expansão térmico da zircônia e da cerâmica de cobertura; a baixa molhabilidade da zircônia pela cerâmica; o processo de sinterização inadequado; as técnicas de processamento e a ausência de rugosidade superficial.5,10,11
Para a criação da rugosidade na zircônia em estudos de laboratório, diferentes tipos de laser e jateamento com óxido de alumínio tem sido aplicado em sua superfície.
3,18-21 Porém, até o presente momento, os estudos realizados apresentaram resultados divergentes. Algumas metodologias desencadearam a transformação da fase tetragonal para monoclínica (t→m), resultando em microfissuras na superfície e criando uma camada de tensão por compressão devido ao aumento do volume dos grãos da zircônia.
3,22-34
Esta revisão sistemática com meta-análise tem como objetivo avaliar a literatura científica disponível e responder a questão da pesquisa: no tratamento da superfície, quais as diferenças resultantes no uso dos lasers de Erbium-YAG, Neodymium-Doped- YAG, ou CO2 e o jateamento de óxido de alumínio na criação da superfície rugosa na cerâmica da zircônia.
2 – METODOLOGIA
2.1 Critérios de Seleção
Esta revisão sistemática foi desenvolvida de acordo com o PRISMA check list e o processo PICO foi usado para desenvolver as estratégias de busca. A população (P) estudada compreendeu espécimes das formas geométricas conforme estabelece a ISO 6872 feitas com o material Zircônia Y-TZP. A intervenção (I) foi caracterizada por metodologias de tratamento para criar rugosidades nas superfícies, baseados em protocolos de abrasão com partículas de óxido de alumínio e com o uso de equipamentos de laser Erbium-YAG, Neodymium-Doped-YAG ou CO2. Foram selecionados apenas os estudos que possuíam o grupo controle (C) sem tratamento superficial. O resultado de interesse (O) foi a rugosidade superficial dos corpos de prova avaliados por um perfilômetro.
Mapeamento conceitual
TERMO DECs/MeSH* Termos livres
P- Population zirconium . zirconium . zirconia
. yttria*
. y-tzp . y tzp
I – Intervention
Air abrasion lasers
. air abrasion*
. sand blasting . sandblast*
. Al2O3
. Laser*
. Er:yag . Nd:yag
. CO2 . Surface treatment C – Control
O - Outcome roughness . Profilometer . Roughness
2.2. Estratégia da Pesquisa
A pesquisa bibliográfica foi realizada nas seguintes bases de buscas: MEDLINE - Biblioteca Nacional de Medicina via PubMed; Web of Science Core Collection e Scopus databases para identificar os artigos relevantes até abril de 2017. Os tópicos médicos específicos (MeSH) e as palavras-chave (termo livre) foram também utilizados. As
pesquisas nas bases de dados eletrônicas foram realizadas de forma independente por dois autores, utilizando as seguintes palavras e termos da estratégia de pesquisa:
MEDLINE via PubMed
(((((((zirconium[MeSH Terms]) OR zirconium[Title/Abstract]) OR zirconia[Title/Abstract]) OR yttria*[Title/Abstract]) OR y-tzp[Title/Abstract]) OR y tzp[Title/Abstract])) AND (((((((((((((Air abrasion, dental[MeSH Terms]) OR lasers[MeSH Terms]) OR Air abrasion, dental[Title/Abstract]) OR lasers[Title/Abstract]) OR laser[Title/Abstract]) OR air abrasion*[Title/Abstract]) OR sand blasting[Title/Abstract]) OR sandblast*[Title/Abstract]) OR al2o3[Title/Abstract]) OR Er:yag[Title/Abstract]) OR Nd:yag[Title/Abstract]) OR co2[Title/Abstract]) OR Surface treatment[Title/Abstract])
SCOPUS
( ( TITLE-ABS-KEY ( zirconium ) OR TITLE-ABS-KEY ( zirconia ) OR TITLE-ABS- KEY ( yttria ) OR TITLE-ABS-KEY ( y-tzp ) OR TITLE-ABS-KEY ( y AND tzp ) ) ) AND ( ( TITLE- ABS-KEY ( air AND abrasion ) OR TITLE-ABS-KEY ( sand AND blasting ) OR TITLE-ABS- KEY ( sandblast ) OR TITLE-ABS-KEY ( al2o3 ) OR TITLE-ABS-KEY ( laser ) OR TITLE-ABS- KEY ( er:yag ) OR TITLE-ABS-KEY ( nd:yag ) OR TITLE-ABS-KEY ( co2 ) OR TITLE-ABS- KEY ( surface AND treatment ) ) ) AND ( ( TITLE-ABS-KEY ( profilometer ) OR TITLE-ABS- KEY ( roughness ) ) )
WEB OF SCIENCE
Tópico: (zirconium) OR Tópico: (zirconia) OR Tópico: (yttria) OR Tópico: (y-tzp) OR Tópico: (y tzp) AND Tópico: (air abrasion) OR Tópico: (sand blasting) OR Tópico:
(sandblast) OR Tópico: (Al2O3) OR Tópico: (lasers) OR Tópico: (Er:yag) OR Tópico:
(nd:yag) OR Tópico: (co2) OR Tópico: (surface treatment) AND (roughness) OR Tópico:
(profiometer)
2.3. Seleção do Estudo
Primeiro os estudos foram revistos de forma independente pelos autores e selecionados para leitura em texto integral caso os títulos e resumos atendessem aos seguintes critérios de inclusão: relação com a Odontologia; relação com a zircônia; ter avaliação da rugosidade da superfície com equipamento de perfilômetro e apresentar os resultados da rugosidade média e do desvio padrão.
Em uma segunda etapa, a inclusão final dos estudos foi realizada com base no texto completo e com o consenso dos autores. Foram incluídos apenas os estudos que possuíam grupos controle adequados sem condicionamento superficial e que foram submetidos ao processo de sinterização. Foram excluídos os estudos que não permitiram a avaliação do efeito isolado do tratamento, tais como aqueles submetidos aos procedimentos térmicos ou testes de força e os de cimentação resinosa ou da aplicação de cerâmica de revestimento nos corpos de prova.
2.4. Avaliação do Risco de Viés
A avaliação do risco de viés foi adaptada tomando por base um estudo anterior, Aurélio IL et al 2016.3 A análise da qualidade dos estudos foi realizada de acordo com os seguintes parâmetros: A) divisão dos corpos de prova em grupos de forma aleatória; B) padronização da confecção dos corpos de prova; C) descrição da metodologia do tratamento da superfície com partículas de óxido de alumínio ou lasers; D) execução do protocolo de operador único; E) demonstração do cálculo do tamanho da amostra; F) cegamento do operador da máquina de ensaio e G) o desenho do ensaio e o cálculo da rugosidade superficial conforme estabelece a norma ISO 4287.
A pontuação foi assim definida: o estudo que apresentou um parâmetro de forma clara recebeu a pontuação ZERO; caso tenha sido relatado de forma incompleta recebeu a pontuação 01; se não foi possível encontrar a informação o artigo recebeu a pontuação 02. Os estudos pontuados de ZERO a 04 foram classificados como de baixo risco, de 05 a 09 como de médio risco e de 10 a 14 como de alto risco de viés.
2.5. Extração e Análise de Dados
Na meta-análise foram utilizados os dados das rugosidades médias e do desvio padrão das superfícies tratadas no grupo experimental com jato de óxido de alumínio e diferentes tipos de lasers. Estes foram comparados com os dos grupos controle sem o tratamento de superfície. Todas as análises foram realizadas utilizando o Cochrane handbook for Systematic Reviews of Interventions Version 5.0.2 como guia e o Review Manager Software versão 5.3 (Cochrane Collaboration, Copenhaga, Dinamarca). Para os estudos que apresentaram múltiplos tratamentos, foi utilizada a calculadora do Review Manager com o fim de combinar os grupos e criar uma comparação de pares simples.
Os estudos foram divididos em três grupos: um global onde foram incluídos os dados de todos os artigos; um para o jateamento com óxido de alumínio e um para todos os tipos de lasers. Nas análises dos subgrupos do jateamento, foram avaliados os efeitos das diferentes metodologias aplicadas antes ou após o processo de sinterização, tanto para a utilização de grit silicone carbide paper durante o processo de confecção do corpo de prova quanto para o jateamento com óxido de alumínio. Para a análise do laser, foram criados subgrupos para os diferentes tipos de lasers.
As estimativas foram expressas comparando os valores da rugosidade média entre os estudos e os sub-grupos. Um valor de p ≤ 0,05 foi considerado estatisticamente significativo (teste Z). A heterogeneidade entre os estudos foi avaliada utilizando tanto o teste Q de Cochran quanto o teste de inconsistência I², nos quais valores acima de 50%
foram considerados como uma indicação de heterogeneidade substancial.
3 - ARTIGOS PRODUZIDOS
Evaluation of the average roughness on the zirconia surface produced with the aluminum oxide sand blasting and the Erbium-YAG, Neodymium-Doped-YAG or CO2 lasers. A systematic review and meta-analysis.
Martins V. Felipe, DDSa, Mattos T. Clláudia, DDS, MS,PhDb, Fonseca M. Edgard, DDS, MS, PhDc
a Post-Graduate Student, Federal Fluminense University (UFF), Niteroi, Rio de Janeiro, Brazil.
bAdjunct Professor, Department of Orthodontics, Federal Fluminense University(UFF), Niterói – RJ.
c Adjunct Professor, Department of Dental Technique, Federal Fluminense University(UFF), Niteroi, Rio de Janeiro, Brazil
Corresponding author:
Felipe Villela Martins
Post-Graduate Student, College of Dentistry, Federal Fluminense University, Niterói – RJ.
Mario Santos Braga St., 28 - Centro, Niterói - RJ, 24020-140 Email: [email protected]
ABSTRACT
Statement of problem.
Adhesive fracture and the decementation of the prosthetic crown, has been shown to be the most frequent failure in restorations using zirconia as an infrastructure. For this reason, some authors propose that a treatment should be done to increase the zirconia surface roughness
Purpose.
The purpose of this Meta-Analysis was to evaluate the results of the average roughness on the Y-TZP zirconia surface, produced with the aluminum oxide sand blasting and the Erbium-YAG, Neodymium-Doped-YAG or CO2 lasers
Material and methods.
This study was performed according to the PRISMA checklist. The bibliographic research was performed to identify in vitro studies until April 2017 in the search bases:
MEDLINE via PubMed; Web of Science and Scopus. The selected studies were submitted to bias risk assessment. In the meta-analysis were evaluated the data of the roughness mean, the standard deviation using Review Manager Software version 5.3.
Results.
The 17 studies, that met all inclusion criteria, presented an medium risk of bias. All the treatment methods tested were able to create roughness on the Y-TZP surface. The I² test values were greater than 90% representing the high heterogeneity among the studies.
Conclusions.
The pre-sintered specimens submitted to sand blasting had higher surface roughness compared to sand blasting after the sintering process. Irradiation with the Nd: YAG and CO2 lasers were destructive on the zirconia surfaces. The Erbium laser used with lower energy intensity is presented as a promising method for surface treatment of zirconia.
Keywords: Zirconia; sandblast; laser; surface treatment; roughness
INTRODUCTION
The zirconia appears in three crystallographic forms: monoclinic, tetragonal and cubic.1,2 Its use in dentistry has become possible by adding components such as calcium, magnesium, yttria or ceria, which, at room temperature, stabilize the metastable tetragonal phase.2 When the zirconia is subjected to thermomechanical factors, the transformation of its tetragonal to monoclinic phase occurs and an increase of approximately 4% in the volume of its grains can be observed.2,3 This phenomenon is called tenacification and is responsible for its high fracture resistance when compared to other ceramics.3,4 Thus, due to this phenomenon, zirconia started to be used as infrastructure for posterior fixed partial dentures and for prosthetic abutments on implants.4-6
The clinical success and reliability of the ceramic system are directly related to the mechanical integrity of the materials and the bond strength at the interface.7-9 Adhesive fracture, also called delamination, and the decementation of the prosthetic crown, has been shown to be the most frequent failure in restorations using zirconia as an infrastructure.10-15 This happens because its physical properties differ from silica based ceramics.7-9,16,17 The absence of the glassy phase and the silicon dioxide makes the zirconia resistant to hydrofluoric acid and not susceptible to silanization. The zirconia–
veneer bond strength is affected by surface wettability, weak mechanical interlock, defect at the interface, coefficients of thermal expansion mismatch and cooling stresses from the veneering process.14-16 For this reason, a new strategy is needed to increase the bond strength at the interface. Some authors propose that a treatment should be done to increase the zirconia surface roughness.3
For the creation of the zirconia roughness in laboratory studies, different types of laser and sand blasting with aluminum oxide have been applied on its surface.3,18-21 However, up to the present time, the studies performed presented divergent results. Some methodologies have triggered the transformation of the tetragonal to monoclinic phase (t
→ m), resulting in microcracks in the surface and creating a layer of tension by compression due to the increased volume of the zirconia.3,22-34
This systematic review with meta-analysis aims to evaluate the available scientific literature and answer the research question: In surface treatment, what are the differences resulting from the use of Erbium-YAG, Neodymium-Doped-YAG, or CO2 lasers and the aluminum oxide sand blasting in the creation of rough surface in zirconia ceramics?
MATERIAL AND METHODS
Eligibility criteria
This systematic review was developed according to the PRISMA check list and the PICO process was used to develop the search strategies. The studied population (P) comprised specimens of the geometric shapes according to ISO 6872 made with Zirconia Y-TZP material. Intervention (I) was characterized by treatment methodologies to create surface roughness based on air abrasion protocols with aluminum oxide particles and with the use of Erbium-YAG, Neodymium-Doped-YAG or CO2 laser equipment. Only those studies that had control group (C) without superficial treatment were selected. The outcome (O) of interest was the surface roughness of the specimens evaluated by a profilometer.
Search strategy
The bibliographic research was carried out in the following search bases:
MEDLINE - National Library of Medicine via PubMed; Web of Science Core Collection and Scopus databases to identify relevant articles throught April 2017 with no limit on publication year. The specific medical subject headings (MeSH) and the key words (free text word) were also used. The researches in the electronic databases were carried out independently by two authors, using the following words and terms of the research strategy:
(((((((zirconium[MeSH Terms]) OR zirconium[Title/Abstract]) OR zirconia[Title/Abstract]) OR yttria*[Title/Abstract]) OR y-tzp[Title/Abstract]) OR y tzp[Title/Abstract])) AND (((((((((((((Air abrasion, dental[MeSH Terms]) OR lasers[MeSH Terms]) OR Air abrasion, dental[Title/Abstract]) OR lasers[Title/Abstract]) OR laser[Title/Abstract]) OR air abrasion*[Title/Abstract]) OR sand blasting[Title/Abstract]) OR sandblast*[Title/Abstract]) OR al2o3[Title/Abstract]) OR Er:yag[Title/Abstract]) OR Nd:yag[Title/Abstract]) OR co2[Title/Abstract]) OR Surface treatment[Title/Abstract])
Study Selection
First, the studies were independently reviewed by the authors and selected for reading in full text if the titles and abstracts met the following inclusion criteria: relation with Dentistry; Relation with zircônia and evaluated the surface roughness with profilometer equipment.
In a second step, the final inclusion criteria of the studies was done based on the complete text and with the consensus of the authors. We included only the studies that met the following criteria: had adequate control groups without surface conditioning; were submitted to the sintering process; and presented the results of the average roughness and the standard deviation. We excluded studies that did not allow the isolated evaluation of the treatment effect, such as those submitted to: thermal procedures or force tests;
resin cementation; or the application of ceramic veneering in the specimens.
Assessment of risk of bias
The risk of bias assessment was adapted based on an earlier study.3 The quality analysis of the studies was performed according to the following parameters: A) division of the specimens into groups in a random manner; B) standardization of the specimens preparation; C) description of the methodology of surface treatment with aluminum oxide particles or lasers; D) implementation of the single operator protocol; E) demonstration of
the sample size calculation; F) blinding of the operator of the testing machine, and G) the design of the test and the calculation of surface roughness according to ISSO 4287 standards.
The score was thus defined: the study that presented a parameter clearly received the ZERO score; If it has been reported incompletely received the score 01; If it was not possible to find the information the article received the score 02. The studies scored from ZERO to 04 were classified as low risk, from 05 to 09 as medium risk and from 10 to 14 as high risk of bias.
Data extraction and analysis
In the meta-analysis, the data of the average roughness and standard deviation of the surfaces treated in the experimental group with aluminum oxide sand blasting and different types of lasers were used. These were compared with those of the control groups without surface treatment. All analyzes were performed using the Cochrane handbook for Systematic Reviews of Interventions Version 5.0.2 as a guide and the Review Manager Software version 5.3 (Cochrane Collaboration). For the studies that presented multiple treatments, the Review Manager calculator was used in order to combine the groups and create a comparison of simple pairs.
The studies were divided into three groups: a global where the data of all articles were included; one for sand blasting with aluminum oxide and one for all types of lasers.
In the analysis of the sand blasting subgroups, the effects of the different methodologies applied before or after the sintering process were evaluated, both for the use of grit silicon carbide paper during the process of making the specimen and for the air abrasion with aluminum oxide. For the analysis of the laser, subgroups were created for the different types of lasers.
Estimates were expressed comparing the mean roughness values between the studies and the subgroups. A value of p ≤ 0.05 was considered statistically significant (Z test). Heterogeneity between studies was assessed using both the Cochran Q test and the I² inconsistency test, in which values above 50% were considered as an indication of
substantial heterogeneity. Sensitivity analyses were performed when there was a high heterogeneity.
RESULTS
Search and selection
In Figure 1 a flowchart summarizes the selection process for the studies according to the PRISMA cheklist. Of 1957 potentially selectable studies, 1910 were excluded because they did not meet the eligibility criteria. The remaining 47 studies were selected for full- text analysis, of which 30 articles were excluded. Thus, a total of 17 studies fulfilled all inclusion criteria and were included in this meta-analysis as listed in Table 1.
Figure 1. Study selection according to PRISMA checklist.
Table 1 - studies included in this meta-analysis.
Author and Year
Y-TZP Brand
Y-TZP Grain Size
Comparison Groups Profilomet er
Equipment
1 - Abi- Rached FO et al 201425
Lava frames 3M ESPE
0.537 μm . 50 μm Al2O3- 15 s - 0.28 Mpa - 10 mm
. 120 μm Al2O3 - 15 s - 0.28 Mpa - 10 mm
. 250 μm Al2O3 - 15 s - 0.28 Mpa - 10 mm
Surftest SJ- 400
Mitutoyo Corp
2 - Subaşı MG et al 201224
VITA In- Ceram®
2000 YZ for inLab
0.6 μm . 110 μm Al2O3- 15 s - 0.3 Mpa - 10 mm
. Er:YAG – 15s – 400mj – 10HZ – 4W –
. Mitutoyo Surftest 402 Series 178
3 -
Sarmento HR et al 201426
Lava, 3M ESPE
0.537 μm . 110 μm Al2O3 - 20 s - 0.25 Mpa - 10 mm
. 110 μm Al2O3 - 20 s - 0.35 Mpa - 10 mm
Wyko NT 1100
Optical Profiling System Veeco 4 - Subaşı
MG et al 201419
VITA In- Ceram YZ for inLab
0.6 μm . 110 μm Al2O3 - 15 s - 0.3 Mpa - 10 mm
. Er:YAG – 15s – 400mj – 10HZ – 4W
Mitutoyo Surftest 402
5 - He M et al 201427
Nissin- Metec
N/A . 110 mesh Al2O3 - 10 s - 0.2 Mpa - 10 mm
. 100 mesh Al2O3 - 10 s - 0.4 Mpa - 10 mm
JB-4C Taiming Optical Instrument
6 - Arami S et al 201420
ICE Zirkon, Zirkonzahn GmbH
N/A . 50 μm Al2O3 - 10 s - 0.28 Mpa - 10 mm
T-8000 Hommelwer
. Er:YAG – 10s – 4.39 J/cm²j – 10HZ – 1.5W – 4mm
. Er:YAG – 10s – 5.85 J/cm² – 10HZ – 2W – 4mm . Er:YAG – 10s – 7.32 J/cm² – 10HZ – 2.5W – 4mm
. Nd: YAG – 60s – 111.96 J/cm² – 10HZ – 1.5W – 1mm
. Nd: YAG – 60s – 149.28 J/cm² – 10HZ – 2 W – 1 mm
. Nd: YAG – 60s – 186.6 J/cm² – 10HZ – 2.5 W – 1 mm
. CO2 – 60s – 2.29 J/cm² – 10HZ – 3 W – 1 mm . CO2 – 60s – 3.05 J/cm² – 10HZ – 4 W – 1 mm . CO2 – 60s – 3.82 J/cm² – 10HZ – 3 W – 1 mm
ke,
JENOPTIK
7 -
Kirmali O et al 201528
Noritake 0.78 μm . 120 μm Al2O3 - 15 s - 0.2 Mpa - 10 mm
. Er:YAG – 20s – 10HZ – 1W – 10 mm
. Er:YAG – 20s – 10HZ – 2W – 10 mm
. Er:YAG – 20s – 10HZ – 3W – 10 mm
. Er:YAG – 20s – 10HZ – 4W – 10 mm
. Er:YAG – 20s – 10HZ – 5W – 10 mm
Mitutoyo Surftest SJ- 301
. Er:YAG – 20s – 10HZ – 6W – 10 mm
8 -
Karakoca S et al 200922
-Cercon Degudent GmbH -DentaCAD Hint-Els GmbH -Zirkonzahn Zirkonzahn GmbH
0.25 – 1.4 μm
N/A
. 110 μm Al2O3 - 15 s - 0.4 Mpa - 30 mm
Surtronic 10 Taylor Hobson
9 - El- Korashy DI et al 201423
inCoris ZI, Sirona
0.4 μm . 110 μm Al2O3 - 10 s - 0.2067 Mpa - 30 mm
TR220 Time Group
10 - Subaşı MG et al 201424
VITA In- Ceram® YZ for in Lab
0.6 μm . 110 μm Al2O3 - 10 s - 0.3 Mpa - 10 mm
Mitutoyo Surftest 402
11 - Demir N et al 201229
VITA In- Ceram YZ for inLab
0.6 μm . 110 μm Al2O3 - 50 s - 0.3 Mpa - 10 mm
. Er:YAG – 15s – 10HZ – 200 mJ - 15.08 J/cm² – 10 mm
. Er:YAG – 15s – 10HZ – 300 mJ - 22.61 J/cm² – 10 mm
. Er:YAG – 15s – 10HZ – 400 mJ - 30.15 J/cm² – 10 mm
Mitutoyo Surftest 402
12 - Arami S et al 201430
ICE Zirkon, Zirkonzahn GmbH
N/A . 50 μm Al2O3 - 10 s - 0.28 Mpa - 10 mm
. Er:YAG – 10s – 10HZ – 2W - 5.85 J/cm²– 4 mm . Nd: YAG – 60s – 10HZ – 1.5 W - 230μsec – 4 mm
T-8000 Hommelwer k JENOPTK
13 - Kirmali O et al 201521
Noritake Co 0.78 μm . 120 μm Al2O3 - 15 s - 0.2 Mpa - 10 mm
. Er, Cr: YSGG – 20s – 20HZ – 1 W – 10 mm . Er, Cr: YSGG – 20s – 20HZ – 2 W – 10 mm . Er, Cr: YSGG – 20s – 20HZ – 3 W – 10 mm . Er, Cr: YSGG – 20s – 20HZ – 4 W – 10 mm . Er, Cr: YSGG – 20s – 20HZ – 5 W – 10 mm . Er, Cr: YSGG – 20s – 20HZ – 6 W – 10 mm
Mitutoyo Surftest SJ-301
14 - Queiroz JRC et al 201231
Cercon Zirconia, Dentsply Ceramco
0.25-1.4 μm
45 μm Al2O3 - 2 s - 0.15 Mpa - 10 mm
45 μm Al2O3 - 2 s - 0.25 Mpa - 10 mm
45 μm Al2O3 - 2 s - 0.45 Mpa - 10 mm
145 μm Al2O3 - 2 s - 0.25 Mpa - 10 mm
145 μm Al2O3 - 2 s - 0.45 Mpa - 10 mm
45 μm Al2O3 - 4 s - 0.15 Mpa - 10 mm
45 μm Al2O3 - 4 s - 0.25 Mpa - 10 mm
NT 1100, Veeco
45 μm Al2O3 - 4 s - 0.45 Mpa - 10 mm
145 μm Al2O3 - 4 s - 0.25 Mpa - 10 mm
145 μm Al2O3 - 4 s - 0.45 Mpa - 10 mm
15 - Cavalcant i AN et al 200932
. Cercon Smart Ceramics Degudent . Procera Zirconia Nobel Biocare
0.25- 1.4um
0.3-1.6 μm
53 μm Al2O3 - 15 s - 0.15 Mpa - 10 mm
. Er:YAG – 5s – 10HZ – 200 mJ
. Er:YAG – 5s – 10HZ – 400 mJ
. Er:YAG – 5s – 10HZ – 600 mJ
Tandem scanning confocal microscope Noran Instruments
16 - Usumez A et al 201333
Ice Zirkon Translucent
; Zirconzahn
N/A . 110 μm Al2O3 - 15 s - 0.28 Mpa - 10 mm
. Nd:YAG – 60 s – 10HZ – 200 mJ - 180 μs
. . Nd:YAG – 60 s – 10HZ – 200 mJ - 320 μs
Perthomete r Mahr
17 -
Elsaka SE 201634
- Zenostar T PSZ ZT, Wieland Dental
- Prettau Anterior FSZ PA, Zirkonzahn
. 50 μm Al2O3 - 20 s - 0.2 Mpa - 15 mm
Surftest SJ-
201 P
Mitutoyo
Risk of bias
The 17 studies presented an medium risk of bias. The test result showed that the most common risks of bias were: absence of the single operator protocol, absence of the sample size calculation description and blind operation of the test machine.
Data Extraction and Meta-analyses
In the meta-analysis, four comparisons were made for a global analysis and for eight subgroups, according to the forest plots of Figure 2, using the average surface roughness data.
In the first analysis, the 17 selected studies were evaluated as shown in Figure 2A.
In this global analysis, a statistical difference between treatments (p ≤ 0.05) was found.
This effect size, 0.77, demonstrated with increased roughness, favored materials submitted to surface treatment with aluminum oxide and laser when compared to the control group. A high heterogeneity was also observed between the studies, evidenced by the I² value of 98%.
The first analysis of the subgroups was performed using the aluminum oxide sand blasting and lasers. In this analysis, 26 data sets were used from the 17 studies included as shown in Figure 2B. The effect size favored the experimental group in both strata, showing higher values for the average roughness (p ≤ 0.05). The largest difference was observed in the lasers subgroup, 1.37, when compared to aluminum oxide blasting, 0.49.
The I² indices between the studies presented high levels of heterogeneity (97% and 98%).
In the second analysis of the subgroups, the influence of the aluminum oxide grain size was evaluated. Nineteen data sets were included as shown in Fig. 2C. The results favored the experimental group in all strata, showing higher values for mean roughness (p ≤ 0.05). The last subgroup had p = 0.08. The result favored the grain of 145 μm as the value of greater surface roughness, 1.07. Subgroups showed heterogeneity above 90%.
The subgroup test showed heterogeneity of 0%.
In the third analysis of the subgroups, the influence of blasting time with aluminum oxide was evaluated. Sixteen datasets were included as shown in Fig. 2D. The results favored the experimental group in all strata, showing higher values for mean roughness (p ≤ 0.05). The result favored the blasting for 20 seconds as the value of greater surface roughness, 0.85. Subgroups showed heterogeneity above 80%. The subgroup test showed heterogeneity of 46.8%.
In the fourth analysis of the subgroups, the influence of the pressure used for blasting with the aluminum oxide was evaluated. Twenty one sets of data were included as shown in Fig. 2E. The results favored the experimental group in all strata, showing higher values for mean roughness (p ≤ 0.05). The result favored the blasting with pressure between 0.15 and 0.2 MPa as the value of greater surface roughness, 0.71. Subgroups showed heterogeneity above 80%. The subgroup test showed heterogeneity of 73.8%.
In the selected scientific articles, different methodologies were observed for the preparation of the test specimens and for the sand blasting with aluminum oxide. These, influenced the results of the average roughness. The methodologies were subgrouped in four modalities: 1st polished with grit silicon carbide abrasive papers in the pre-sintered stage and sandblasted with aluminum oxide after the sintering process; 2nd polished with grit silicon carbide abrasive papers in the pre-sintered stage and sandblasted with aluminum oxide after the sintering process; 3rd polished with grit silicon carbide abrasive papers in the post sintered step and sandblasted with aluminum oxide after the sintering process; 4 did not polished and sand blasting with aluminum oxide after the sintering process. For the analysis of these subgroups, 16 data sets were included as shown in Figure 2F. The results favored the experimental group with abrasion in the first three strata, showing higher mean roughness values than those in the control group (p ≤ 0.05).
The last subgroup presented p = 0.06. All strata showed high levels of heterogeneity above 95% when evaluated individually. The for subgroups diferences showed a heterogeneity of 23.1%. The group that used grit silicon carbide abrasive papers in the pre sintered stage and sand blasting with aluminum oxide in the pre sintered stage presented effect size of 2.71 as the value of greater surface roughness. However, this
subgroup represents only 5.3% of the studies conducted so far, which recommends a more extensive research.
In the last analysis of the subgroups, as shown in Figure 2G, the subgroups were examined according to the type of laser and included 11 data sets. It was not possible to create a subgroup for the CO2 laser, since only one study presented average roughness results for this treatment. The results favored the experimental group in both subgroups that presented mean roughness values higher than the control group (p ≤ 0.05). The effect size favored the Nd: YAG laser as the highest surface roughness value, 4.15, when compared to the Er: YAG laser, 0.60. The subgroups of Er: YAG and Nd: YAG lasers presented heterogeneity of 97% and 98%.
Sensitivity analyses were performed for all comparisons to try to identify the studies responsible for the high heterogeneity detected. However, none of the combinatios tried led to a decrease in heterogeneity.
Figure 2A. Forest plots according to the global analysis (air-particle abraded vs. control);
Figure 2B. Forest plots according to the analyses of subgroup: air-particle abraded vs.
Control ans laser vs. Control
Fig. 2C - Forest plots according to the analyses of subgroup: : 1st 45 – 53 μm; 2st 110 μm; 3st 120 μm; 4st 145 μm.
Fig. 2D - Forest plots according to the analyses of subgroup: : 1st 10 seconds; 2st 15 seconds; 3st 20 seconds.
Fig. 2E - Forest plots according to the analyses of subgroup: : 1st 0.15 – 0.2 Mpa; 2st 0.25 – 0.28 Mpa; 3st 0.3 – 0.35; 4st 0.4 – 0.45 Mpa.
Figure 2F. Forest plots according to the analyses: 1ª grit silicon carbide abrasive papers during pre sintered phase and sandblating during pre sintered phase; 2ª grit silicon carbide abrasive papers during pre sintered phase and sandblating after sintered; 3ª grit silicon carbide abrasive papers after sintered process and sandblating after sintered; 4ª no Polishing and sandblating after sintered.
Figure 2G. Forest plots according to the analyses of Er:YAG and Nd:YAG
DISCUSSION
In the results of present study, all treatment protocols were capable of altering surface roughness. The meta-analysis showed high data heterogeneity as well as high standard deviation, as was observed by Aurélio IL et al.3 The variables observed in the preparation of the specimens and the methodologies adopted in the treatment of the surfaces can influence the results, justifying the high heterogeneity found.
The preparation of the specimens consists of cutting the zirconia and the use of a grit silicon carbide abrasive papers sequence to obtain a smooth surface. Of the 17 scientific papers selected, 13 different methodologies were used for the preparation of the test specimens. The use of grit silicon carbide abrasive papers played a key role in the results obtained in the control groups Ra value.21,25,27,28 However, the details of the polishing protocols are not displayed. The specimens that were polished still pre-sintered, because they were soft, presented higher surface roughness and absence of grooves when compared to the polished ones after the sintering process.21,28
With regard to the improvement of micromechanical retention, techniques such as air abrasion with aluminum oxide particles (Al2O3) have been shown to be one of the most investigated resources. In 94.7% of the articles selected in this systematic review the abrasion was performed after the sintering process. In only 5.3% the surface treatment was performed before the sintering process.27,28
The performance of the sand blasting with aluminum oxide before the sintering process was presented as the most effective method.27,28 Because the pre-sintered zirconia surface was soft, it was more affected by the blasting. This provided the formation of a rougher surface, with more prominent and irregular micro retentive grooves. This modification allowed the use of smaller particles of aluminum oxide and the use of lower air pressure. It also made it possible to avoid: the transformation of the tetragonal phase into the monoclinic phase (t → m), the formation of microcracks and the removal of the zirconia grains.27,28
Sintered zirconia presents as a high stiffness material, which makes it difficult to change its surface morphology.3 Therefore, to perform the sand blasting with aluminum oxide, the authors present as an option: increase the air pressure;22,24,27,31 include particles of larger diameter;21,25,27,28,31 increase the blasting time or the combination of these items to create surface roughness.25,34 However, excessive abrasion is believed to stress the zirconia surface and accelerate the t → m transformation. Thus, a greater impact energy of the particles can cause loss of ceramic material or the formation of microcracks that can propagate, compromise its mechanical properties and cause premature failure.4,20,26
Regarding the Nd: YAG laser, different protocols were tested. Studies have indicated that this laser can alter the zirconia ceramics surface.20,30,33 They also showed that treatment with a power of 1.5 W created surface microcracks, prominences and porosities.20,30 The authors reported that the microcracks became obvious by increasing the irradiation intensity forming large flaws and loss of ceramic material.20 Arami et al reported that 2 and 2.5 W irradiation caused areas of surface melting, large cracking and a carbonized layer with silver pigments.20 Usumez et al confirmed that the treatment with the Nd: YAG laser induces the zirconia transformation to the monoclinic phase.33
The methodology used in this systematic review found only one study where it was possible to observe the result of the average roughness obtained with the CO2 laser.
Arami et al reported that the high temperature generated by the CO2 laser facilitates the melting of the zirconia surface and the creation of microcracks in the surface.20
The laser works by transforming the energy irradiated into heat.35-38 Absorption is influenced by pigmentation, amount of water and surface roughness.29,35,36 Studies indicate that the cited defects are formed on the zirconia surface during the local temperature change.38 The melting and solidification process generates a volume change in the material, creating internal stress and cracking.37,38
The Er: yag and Er Cr: YSGG lasers have the ability to remove particles by a process of ablation by micro-explosions and vaporization.18,21,39 The observed results were compatible with the same premise of the lasers presented previously. Increasing the irradiation time or the energy used resulted in higher average roughness.21 Also, it has been reported the fusion of the ceramic material, the formation of microcracks and the color change in some cases.19,29,30 Subaşı et al stated that the micro-explosions create debris that can adhere to the melted ceramic surface, bind to the resin cement and compromise the bond strength.19
The use of Erbium laser is still a promising option. Cavalcanti et al have expressed that the lower energy intensity may be a viable method for surface treatment of zircônia.32 Arami et al reported that surfaces treated by the Er: YAG laser, at their lowest power, showed a surface roughness similar to abrasion with aluminum oxide.20
One factor in common among the studies that used laser is the absence of a methodology for the laser application, independent of the type of laser used. In all the research the laser equipment produced beams with diameters of 0.3 mm to 1.3 mm and were applied manually. This application model can result in untreated areas or over- irradiated areas. Treatment parameters should be controlled to avoid loss of material and consequent defects.
CONCLUSION
Based on the results of this systematic review, we can conclude that: A) All the treatment methods tested were able to create roughness on the surface of the Y-TZP zirconia ceramics; B) Sand blasting with aluminum oxide on the pre-sintered zirconia presented the best result for the surface roughness; C) Erbium laser used with lower energy intensity presented a surface roughness similar to the abrasion with aluminum oxide.
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4 - CONCLUSÕES
Com base nos resultados desta revisão sistemática, podemos concluir que:
A) todos os métodos de tratamento testados foram capazes de criar rugosidades na superfície da cerâmica de zircônia Y-TZP;
B) o jateamento com óxido de alumínio na superfície da cerâmica de zircônia pré- sinterizada apresentou o melhor resultado para a rugosidade média. Os autores relataram a ausência de transformação da fase tetragonal para a monoclínica;
C) a irradiação com os lasers Nd: YAG e CO2 foram destrutivas nas superfícies da zircônia. A alta temperatura gerada pelos lasers levaram a fusão da superfície da zircônia e a criação de microfissuras na superfície;
D) o laser de Erbium utilizado com menor intensidade de energia se apresenta como uma opção promissora, mostrando uma rugosidade superficial semelhante à abrasão com óxido de alumínio;
Em pesquisas futuras, os autores deverão desenvolver uma metodologia que aborde: o controle do processo de tratamento da superfície; não provocar a formação de microtrincas e que seja capaz de aumentar a rugosidade na cerâmica da zircônia Y-TZP.
