UNIVERSIDADE ESTADUAL DE CAMPINAS FACULDADE DE ODONTOLOGIA DE PIRACICABA
VINICIUS RODRIGUES DOS SANTOS
ANÁLISE TRIBOLÓGICA DA INTERFACE OSSO-TITÂNIO E
SUA INFLUÊNCIA NA BIOMECÂNICA DE IMPLANTES
CURTOS UNITÁRIOS COM DIFERENTES TRATAMENTOS
DE SUPERFÍCIE
TRIBOLOGICAL
ANALYSIS
OF
BONE-TITANIUM
INTERFACE AND INFLUENCE ON UNIT SHORT IMPLANTS
BIOMECHANICS
WITH
DIFFERENT
SURFACE
TREATMENTS
Piracicaba 2018
VINICIUS RODRIGUES DOS SANTOS
ANÁLISE TRIBOLÓGICA DA INTERFACE OSSO-TITÂNIO E SUA INFLUÊNCIA NA BIOMECÂNICA DE IMPLANTES CURTOS UNITÁRIOS COM DIFERENTES TRATAMENTOS DE SUPERFÍCIE
TRIBOLOGICAL ANALYSIS OF BONE-TITANIUM INTERFACE AND
INFLUENCE ON UNIT SHORT IMPLANTS BIOMECHANICS WITH DIFFERENT SURFACE TREATMENTS
Dissertação apresentada à Faculdade de Odontologia de Piracicaba da Universidade Estadual de Campinas como parte dos requisitos exigidos para a obtenção do título de Mestre em Clínica Odontológica, na Área de Prótese Dentária
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 Dental Prosthetics area.
Orientador: Prof. Dr. Wander José da Silva Este exemplar corresponde à versão final da dissertação defendida pelo aluno Vinicius Rodrigues dos Santos e orientada pelo prof. Dr. Wander José da Silva
Piracicaba 2018
Agência(s) de fomento e nº(s) de processo(s): Não se aplica. ORCID: orcid.org/0000-0002-0369-3485
Ficha catalográfica
Universidade Estadual de Campinas Biblioteca da Faculdade de Odontologia de Piracicaba
Marilene Girello - CRB 8/6159
Santos, Vinicius Rodrigues dos, 1991-
Sa59a Análise tribológica da interface osso-titânio e sua influência na biomecânica de implantes curtos unitários com diferentes tratamentos de superfície / Vinicius Rodrigues dos Santos. – Piracicaba, SP : [s.n.], 2018.
Orientador: Wander José da Silva.
Dissertação (mestrado) – Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba.
1. Implantes dentários. 2. Análise de elementos finitos. 3. Fricção. I. Silva, Wander José da, 1980-. II. Universidade Estadual de Campinas. Faculdade de Odontologia de Piracicaba. III. Título.
Informações para Biblioteca Digital
Título em outro idioma: Tribological analysis of bone-titanium interface and influence on
unit short implants biomechanics with different surface treatments
Palavras-chave em inglês:
Dental implants
Finite element analysis Friction
Área de concentração: Prótese Dental Titulação: Mestre em Clínica
Odontológica Banca examinadora: Wander José da Silva [Orientador] Aldiéris Alves Pesqueira
Antônio Pedro Ricomini Filho
Data de defesa: 23-02-2018
UNIVERSIDADE ESTADUAL DE
CAMPINAS Faculdade de
Odontologia de Piracicaba
A Comissão Julgadora dos trabalhos de Defesa de Dissertação de Mestrado, em sessão pública realizada em 23 de Fevereiro de 2018, considerou o candidato VINICIUS RODRIGUES DOS SANTOS aprovado.
PROF. DR. WANDER JOSÉ DA SILVA
PROF. DR. ALDIÉRIS ALVES PESQUEIRA
PROF. DR. ANTÔNIO PEDRO RICOMINI FILHO
A Ata da defesa com as respectivas assinaturas dos membros encontra-se no processo de vida acadêmica do aluno.
AGRADECIMENTOS
Agradeço, primeiramente a Deus, que permitiu que tudo isso acontecesse, ao longo de toda minha vida, minha eterna gratidão por tudo que fez e ainda fará por mim.
À Faculdade de Odontologia de Piracicaba, na pessoa de seu diretor Prof. Dr. Guilherme Elias Pessanha Henriques, incluindo todos os docentes e funcionários, pela oportunidade da realização desse trabalho e pelos conhecimentos transmitidos a mim durante esse período.
Ao Prof. Dr. Wander José da Silva, pela atenção e imenso apoio durante o processo de definição e orientação deste trabalho.
À Prof. Dra. Altair Antoninha Del Bel Cury, Prof. Dr. Carlos Alberto Fortulan, Prof. Dr. Dimorvan Bordin e Prof. Dr. Luiz Carlos Carmo Filho pelo auxílio e apoio na realização deste trabalho durante esse período. Grato por tudo.
À minha noiva Kamila Miranda Prado por todo amor, carinho, compreensão, paciência e atenção em todos os momentos da minha vida.
Aos meus amigos do Laboratório da PPR e à Técnica de Laboratório Gislaine pela amizade que adquirimos durante esse tempo na realização do projeto.
A Signo Vinces e ao Angenheiro Andreas Reinhard Firzlaff por fornecer os materiais necessários para realização deste projeto.
.
RESUMO
A análise da biomecânica dos implantes em estudos através do método de elementos finitos (MEF) tem sido avaliada com valores de coeficiente de atrito (CA) arbitrários, o que não representa a condição ideal quando simulada uma condição de carregamento imediato. Nesta situação, os diferentes tipos ósseos e os tratamentos de superfície do titânio podem levar a diferentes CA na interface osso-implante. Diante disso, o objetivo desse estudo foi determinar o CA da interface osso-titânio com tratamentos de superfície e verificar sua influência na biomecânica de implantes curtos com diferentes tratamentos de superfície sob carga imediata em reabilitações unitárias. Para isto, este estudo foi dividido em duas fases distintas: in vitro e in sílico. No estudo in vitro, o CA foi determinado com o auxílio de um tribômetro. Blocos de osso cortical e medular bovino (10 mm x 40 mm x 3 mm) e esferas de titânio como contraparte, com diferentes tratamentos de superfície (USI = usinada; JAT = jateada; e J+A = jateada seguido de ataque ácido) com 5 mm de diâmetro foram utilizados como pares tribológicos (n=13). As esferas de titânio tiveram sua rugosidade (n=5) mensuradas e analisadas por microscopia eletrônica de varredura (MEV) para analisar a diferença das superfícies. Uma carga de 10 N foi aplicada e mantida na contraparte durante o deslocamento horizontal sobre o bloco ósseo (1 mm/segundo). Para o estudo in sílico um primeiro molar inferior foi reabilitado utilizando modelo tridimensional de implante curto (4.1 x 7mm) inserido em bloco ósseo representando uma mandíbula com reabsorção óssea. Os resultados do CA obtidos no estudo in vitro foram utilizados para simular por meio do MEF o comportamento biomecânico dos implantes nas superfícies avaliadas frente à carga imediata. A força aplicada foi de 49 N na face oclusal da coroa e dividida uniformemente em 5 pontos de contato. As análises estatísticas foram realizadas par a rugosidade do titânio e determinação do CA, para ambas as análises o teste estatístico foi o ANOVA One-Way, post-hoc Tukey. Os valores foram avaliados segundo a tensão de cisalhamento (max) e tensão principal máxima (σmax) realizadas no osso cortical e medular. A tensão de von Mises (vM) foi avaliada no implante dos diferentes tratamentos de superfície. A rugosidade das esferas de titânio tratadas com JAT (0,89 µm) e J+A (0,98 µm) não mostraram diferenças estatísticas. Os valores do coeficiente de atrito de J+A se mostraram maiores numericamente para osso medular e cortical, respectivamente, (0,415 ± 0,05)(0,442±0,05) comparado a JAT (0,358 ± 0,03)(0,382 ±0,03) e USI (0,0314 ± 0,04)(0,362 ±0,03). A biomecânica foi alterada pelos tratamentos de superfície, onde J+A mostrou maior compressão (495,47 MPa) e desgaste (197,46 MPa) da superfície implante-osso e menor deformação (10,65 µm) e tensão óssea quando comparado a JAT no osso cortical. No osso
medular a superfície J+A apresentou menor valor nas avaliações biomecânicas comparado a JAT. Portanto, podemos concluir que os tratamentos de superfície alteram o CA da interface osso-titânio, interferindo na biomecânica de implantes curtos unitários sob carga imediata. Palavras-Chaves: Implantes Curtos; Análise de elementos finitos; Fricção.
ABSTRACT
The implants biomechanical analysis using finite element analysis (FEA) was evaluated with arbitrary friction coefficient (FC) values. This analysis does not represent a better condition to simulate immediate loading. In addition, different bone types and titanium surface treatments can change the FC on bone-implant interface. Therefore, the aim of this study was determine the FC of bone-titanium interface with surface treatments and analyze your influence on biomechanics of unit short implant with different surface treatments. For this, the study was done in two phases: in vitro and in silico. On in vitro study, the FC was determined with tribological analysis. Bovine cortical and cancellous bone (10 mm x 40 mm x 3 mm) and titanium as counterpart, with different surface treatments (MAC = machined; SB = sandblasted; and SB + AE = sandblasted followed by acid attack) with diameter of 5 mm were used as tribological pairs (n = 13). Titanium balls was mensured our roughness by scanning electron microscopy (SEM) to analyse difference between the surfaces. A load of 10 N was applied on titanium counterpart during the horizontal displacement on bone blocks (1 mm/sec). For in silico study, a first molar was rehabilitated using a three-dimensional short implant model (4.1 x 7mm) inside bone block representing a jaw with cortical and cancellous bone. The results of the FC obtained in vitro study were used to simulate the biomechanics behavior of short implants with different surface treatment. The force applied was 49 N on occlusal of the crown and divided into 5 contact points. Statistical analysis was realized to roughness and FC determination, for both analysis the statistical test was ANOVA One-Way, post-hoc Tukey. The values were evaluated for shear stress (max) and maximum principal strain (σmax maximum standard) to cortical and cancellous bone. Von Mises forces (vM) was evaluated for implants. Surface roughness on SEM of titanium balls shown the values of SB (0.89 µm) and SB + AE (0.98 µm) with no statistical difference. The surface treatment SB + AE for cortical and Cancellous bone was numerically greater, respectively,(0,415 ± 0,05)(0,442±0,05) than SB (0,358 ± 0,03)(0,382 ±0,03) and MAC (0,0314 ± 0,04)(0,362 ±0,03). The surface biomechanics was modified according the surface treatment and SB + AE showed the highest compression (495.47 MPa) and shear (197.46 MPa), but in deformation and tension was lowest (10.65 m) compared to surface SB on cortical bone. On cancellous bone, the surface SB + AE presented lowest in the biomechanics evaluations. Therefore, we can conclude the surface treatments alter FC of titanium-bone interface and interfere on biomechanics of unit short implant with immediate loading.
SUMÁRIO
1- INTRODUÇÃO ... 10
2- ARTIGO: IMPLANT SURFACE TREATMENT AFFECTS THE BIOMECHANICS OF IMMEDIATE SHORT IMPLANT LOADING ... 12
3- CONCLUSÃO ... 30
4- REFERÊNCIAS ... 31
ANEXOS ... 34
Anexo 1: Análise Estatística – Coeficiente de Atrito ... 34
Anexo 2: Análise Estatística – Rugosidade de Superfície ... 46
Anexo 3: Comprovante de Submissão ... 58
1- INTRODUÇÃO
O edentulismo e sua consequente reabsorção óssea na região posterior da mandíbula faz com que ocorra uma dificuldade na instalação de implantes convencionais devido à falta de comprimento nesta região (Esposito et al., 2016). Com isso, nota-se uma predominância óssea com espaços medulares reduzidos e com maior espessura cortical. Essa dificuldade da instalação de implantes em região posterior da mandíbula representa um desafio na reabilitação do indivíduo, o que dificulta a etapa cirúrgica e, consequentemente, o processo de osseointegração devido estas alterações ósseas (Al-Sabbagh e Bhavsar, 2015).
Considerando que o processo de reabsorção ocorre predominantemente no sentido vertical, faz com que o rebordo reabsorvido aproxime-se do nervo alveolar inferior, o que inviabiliza a reabilitação com implantes convencionais. Neste sentido, implantes curtos, geralmente menores ou iguais a 7 mm, são utilizados como tratamento de eleição para reabilitações orais de regiões com reabsorção óssea (Maló et al., 2007; Nisand e Renouard, 2014; Alvira-González et al., 2015). Isso faz com que cirurgias de alto grau de morbidade sejam evitadas, como lateralização do nervo alveolar inferior e a utilização de enxertos ósseos (Esposito et al., 2011). Isto reduz a complexidade e morbidade do tratamento, tempo e o número de procedimentos necessários para a reabilitação (Koirala et al., 2016).
A crescente indicação do uso de implantes osteointegrados na reabilitação oral levou a estudos que visavam o aumento das taxas de osteointegração. Neste sentido, modificações na superfície de implantes dentários (Coelho et al., 2009b) estão entre as soluções destinadas a tal fim. Contudo, a modificação da superfície de implantes pode gerar diferenças imediatas durante a instalação dos implantes ao alterar o coeficiente de atrito entre a superfície do implante e do osso podendo alterar o modo como as cargas mastigatórias sob a superfície óssea são distribuídas (Huang et al., 2008). Em pacientes submetidos à carga imediata, a estabilização da interface osso-implante e o modo como as cargas são distribuídas podem ser determinante para o sucesso da reabilitação (Gao et al., 2014; Rossi et al., 2015)
Considerando a biomecânica das reabilitações com implantes curtos, estudos atuais mostram uma alta taxa de sobrevivência destes implantes, alcançando taxas de sucesso de 97%, quando reabilitados com próteses fixas esplintadas em carga imediata (Alvira-González et al., 2015), mas pouco se fala de sua reabilitação em elementos unitários. Devido ao desconhecimento da biomecânica em conjunto com as dificuldades da realização de ensaios clínicos randomizados para avaliar implantes curtos unitários com diferentes tratamentos de
superfície, metodologias alternativas como análise por elementos finitos tem sido empregadas com sucesso na área da implantodontia (Jayme et al., 2015; Santiago et al., 2016). Trata-se de uma ferramenta rápida e preditiva para compreender melhor a complexidade dos mecanismos envolvidos na reabilitação oral (Bordin et al., 2015; Caglar et al., 2011; Chun et al., 2005; Guda et al., 2008; Hanaoka et al., 2014; Khraisat, 2012; Lang et al., 2003).
Porém, na análise do método de elementos finitos, a impossibilidade de considerar a superfície de contato entre um implante submetido à carga imediata e o osso como sendo perfeitamente unidas (Yazicioglu et al., 2015) leva a necessidade da obtenção de valores do coeficiente de atrito dessa interface, onde sugere-se que tratamentos da superfície do titânio ou a interposição de fluídos entre as superfícies possam gerar diferentes valores. Para o estudo da biomecânica dessa alteração, coeficientes de atrito entre a superfície osso-implante tem sido utilizadas de forma arbitrária, variando de 0,3 a 1,0 (Huang et al., 2008; Pessoa et al., 2010; Ferreira et al., 2014). Essa arbitrariedade pode levar a resultados que não simulam a real condição existente entre as estruturas, comprometendo a acurácia e interpretação dos resultados.
Dessa forma, faz-se necessário determinar o real coeficiente de atrito entre osso-titânio com ou sem tratamentos de superfície para simular, através da metodologia dos elementos finitos, corretamente a biomecânica dos implantes curtos unitários em mandíbulas com reabsorção óssea sob carregamento imediato.
2- ARTIGO
IMPLANT SURFACE TREATMENT AFFECTS THE BIOMECHANICS OF IMMEDIATE SHORT IMPLANT LOADING
Authors:
Vinicius Rodrigues dos Santos - FOP-UNICAMP Dimorvan Bordin – FOP-UNICAMP
Luiz Carlos Carmo Filho – FOP-UNICAMP
Prof. Carlos Alberto Fortulan – USP/SÃO CARLOS Profa. Altair Antoninha Del Bel Cury – FOP-UNICAMP Prof. Wander José da Silva – FOP-UNICAMP
Abstract
The biomechanics of immediate short implant loading to finite element analysis (FEA) had been used with arbitrary values of friction coefficient (FC). In our study we aimed to determine the bone-titanium FC and use this value in FEA to evaluate the biomechanics of immediate short implant loading. The study was divided into two phases: in vitro and in silico. On the in vitro study, the FC was determined with tribological analysis. Titanium balls with different surface treatments: Machined (MAC), sandblasted with aluminum oxide (SB) and sandblasted treatment with aluminum oxide followed by acid etched with hydrofluoric acid and sulfuric acid (SB + AE) were used as tribological pair with bovine cortical or cancellous bone blocks and scanning electron microscopy images and rougness was done on titanium to surface analysis. For the in silico study, we used the FC obtained in vitro study in a three-dimensional short implant model of a first molar inside a bone block representing a jaw with cortical and cancellous bone. The biomechanics of bone-titanium interface was modified according to the surface treatment. The surface SB + AE showed a greater compression (495.47 MPa) and shear (197.46 MPa), but in deformation and tension was lowest (10.65 m) compared to surface JAT in the cortical bone. In the Cancellous bone, the surface SB + AE presented lowest on all the biomechanics evaluations. Therefore, we conclude that different surfaces alters FC on implant-bone interface and different FC affect short implants biomechanics under immediate loading. Keywords: immediate loading in dental implant; Finite element analysis; Friction; Short Implants.
Introduction
The use of osteointegrated convencional lenght implants is affected by the reabsorbed posterior jaws due to the surgical difficult and it compromises the osseointegration process (Al-Sabbagh and Bhavsar, 2015). Posterior jaw bone reabsorption process occurs predominantly on vertical direction and this causes a proximity to posterior alveolar nerve with leads to the impossibility of the rehabilitation with conventional implants. In this sense, short implants, usually smaller than 7 mm, are used as treatment for oral rehabilitations of bone resorption regions (Nisand and Renouard, 2014; Alvira-González et al., 2015; Pieri et al., 2017). The use of short implants avoid high difficulty and morbidity surgeries, such as inferior alveolar nerve lateralization and bone grafts (Esposito et al., 2011). Thus, short implants reduce complexity and morbidity of treatment, time and a few procedure sessions to final rehabilitation (Koirala et al., 2016)
Higher indications of dental implants in oral rehabilitations stimulates studies that increase osseointegration process rates. In this sense, changes on dental implants surface (Coelho et al., 2009b) are one of the solutions designed to increase the osseointegration process. However, surface modification in dental implants may generate immediate differences during implants installation and change the friction coefficient between bone-implant surface and may interfere the chew loads under the bone surface (Huang et al., 2008). In patients under immediate loading, stabilization on the bone-implant interface and how the loads are distributed may be crucial to the rehabilitation success (Gao et al., 2014; Rossi et al., 2015).
Considering implant rehabilitations, current studies show a high survivor rate of short implants, the success rates were 97%, when was rehabilitated with splinted fixed prostheses in immediate loading (Alvira-González et al., 2015), but there is no data of rehabilitation with short implants using single crown elements. Considering the unknown biomechanics and all difficulties to conduct a randomized clinical trials for single crown of short implants with different surface treatments, alternative methods such as finite element analysis has been employed successfully on implant dentistry (Jayme et al., 2015; Santiago et al., 2016). It is a rapid and predictive tool to understand the complexity of mechanisms involved in oral rehabilitation (Lang et al., 2003; Chun et al., 2005; Guda et al., 2008; Çaglar et al., 2011; Khraisat, 2012; Hanaoka et al., 2014; Bordin et al., 2015).
However, on the FEA, it is impossible considering the surface contact between bone-implant in immediate loading as perfectly bonded (Yazicioglu et al., 2015). Therefore, obtaining the values of friction coefficient interface is necessary, where it is suggested titanium
surface treatments or fluids interposition between surfaces may generate different friction coefficient values. From our knowledge, the FEA studies had been used arbitrarily FC between bone-implant surface, ranging from 0.3 to 1.0 (Huang et al., 2008; Pessoa et al., 2010; Ferreira et al., 2014). This arbitrariness may lead to results that do not simulate the actual existing condition between the structures, compromising the accuracy analysis and the results interpretation.
Thus, in this study, we aimed to analyze the bone-titanium interface to determine the FC with different titanium surface treatments and, then, simulate by FEA the biomechanics of short implants under immediate loading.
Materials and Methods Experimental Design
This study was divided into two distinct phases: in vitro and in silico study. The in vitro study (n=13) counted on cortical and cancellous bone blocks (10 mm x 40 mm x 3 mm) allocated randomly by lottery to tribological test. They were divided into 3 groups (SB + AE, SB or MAC). The titanium surface analysis was performed by scanning electron microscopy (SEM). The surface roughness of titanium ball was measured by perfilometer (n=5). Friction coefficient was determined using a tribometer, a titanium ball (5 mm of diameter) treated by SB + AE, SB or MAC was used as a counterpart. A load of 10N was applied and maintained on bone counterpart during the horizontal displacement on the bone block (1 mm/sec). In the second phase (in silico) a first molar was rehabilitated using a three-dimensional model of short implant inserted in a block representing a reabsorbed jaw bone. The FC obtained in vitro study were used to simulate the biomechanical behavior of dental implants under immediate loading. A force of 49 N was applied on tooth occlusal surface also 5 points of contact. The values obtained were evaluated according to shear stress (max) and maximum principal stress (σmax) to the bone and von Mises tension (vM) on implant and prosthetic components. Statistical analysis was performed to compare the differences between friction coefficient of surfaces at bone-implant interface and surface roughness of titanium surfaces. It was considered as dependent variable the friction coefficient and as the independent variable the titanium surface treatment and its roughness.
In Vitro
Samples Preparation:
Cortical and cancellous bone: The bone blocks were acquired by fresh bovine ribs obtained on the butchery and cleaned by removing scraped soft tissue with a scalpel blade (Duflex, Curitiba, Paraná, Brazil). A diamond blade was used to cut cortical and cancellous bone blocks with dimensions of 10 mm x 40 mm x 3 mm (n = 26)(Isomet Low Speed Saw, Buehler Ltda., Lake Bluff, IL, USA). Afterwards, they were polished in low speed (250 rpm) with a metallographic polishing machine (APL 4, Arotec, Cotia, São Paulo, Brazil) with 600 mesh granules followed by 1200 for 2 minutes each. After, the blocks were embedded in acrylic resin (JET – Artigos Odontológicos Clássico LTDA – Campo Paulista – SP – Brasil) and were cleaned in an ultrasonic bath for 15 minutes in distilled water.
Titanium: Titanium balls used as counterpart were made using CAD / CAM models (Solidworks 2013, Solidworks Corporation, MA, USA) using commercially pure titanium which were divided into 3 groups (n=26): Machined (MAC), treatment with aluminum oxide (JAT) and blasting treatment with aluminum oxide followed by acid etching with hydrofluoric acid and sulfuric acid (J + A). The titanium preparation as well as the surface treatments were performed and standardized according to manufacturer under same conditions was done on commercial implants. (Signo Vinces Equipamentos Odontológicos LTDA - Campo Largo - Paraná - Brazil). The condiction of this tretaments was a industrial confidence.
Scanning electron microscopy (SEM): Titanium with different treatments were observed by MEV (JEOL JSM-5600LV; Peabody, MA, USA) with 500x and 3000x of magnification, at a voltage of 15 kV and with a slope of 60 degrees to evaluate the different surfaces of titanium.(Nemtoi et al., 2017)
Surface roughness: A roughness perfilometer (Surfcoder SE 1700 - Kosaka Laboratory LTD - Japan) was used to analyze titanium surface roughness. The parameters used to the roughness analysis was velocity of 1mm/seg and 3 repetitions per titanium ball. The average surface roughness (Ra) parameters of all surfaces were obtained (n = 5).(Senna et al., 2013)
Desfibrinated Sheep Blood: To simulate surgical site at the time of implantation, sheep blood was used simulating the presence of blood from jaw bone perforation. A 50 ul aliquot of Ram blood was placed with a pipette (Eppendorf Research 1- 100 μl) on the cortical and cancellous bone surface.
Friction coefficient determination: The cortical and cancellous bone were attached to tribometer support and the desfibrinated sheep blood (50µl), simulating the surgical site, was placed on its surface (pin against the disc)(Faculty of Mechanic Engineering: USP, São Carlos, SP, Brazil). The test was performed by sliding 10 N vertical load applied to each block with the Titanium counterpart of MAC, SB and SB + AE with diameter of 5 mm. The test was done with a stroke length of 10 mm at 1 mm/sec under controlled ambient conditions, 25 °C and ambient humidity of 55% of site where the tribological test was performed. The dynamic friction coefficient was evaluated by LabVIEW® software (National Instruments®, São Paulo, SP, Brazil).(Bordin et al., 2015)
In silico - Finite Element Analysis
Obtaining three-dimensional models: We used Solidworks drawing program (Solidworks 2013, Solidworks Corporation, MA, USA) and microtomographic images (μCT) of a molar tooth (46) and geometric model of total crown was made (fig. 01). For reabsorbed jaw, a geometric model were obtained a file (.STL) with a computed tomography images of a reabsorbed jaw, available on image database (Prosthesis Laboratory - FOP / UNICAMP - Piracicaba - Brazil), simulating proximity to inferior alveolar nerve. The bone structure was reconstructed in Invesalius software (Renato Archer Information Technology Center, Campinas, Brazil) and then the image was transported to Solidworks program for the incorporation of prosthetic crown implant. The 3-D models of implant and prosthetic components were obtained through CADs provided by dental implants company (Neodent - JJGC IND. AND DENTAL MATTERS S.A. - Curitiba - Paraná - Brazil).
Figure 01. Structures used for the Finite Elements Analysis. A – geometrical model of the implant, cortical and cancellous bone. B – Mesh of the final model used in analysis. C –
Rendered final geometrical model used in analysis. D – Rendered final geometrical model of the short implant used in analysis. E – Location of the load application.
A dental implant type Cone Morse (4.1 x 7mm) (Neodent - JJGC IND. AND COM. DE DENTÁRIOS SA - Curitiba - Paraná - Brazil) was simulated and a crown cemented on conical abutment (Neodent - JJGC IND. The thickness of resin cement layer was 70 μm, simulating use of the resinous cement Panavia F (Kuraray Medical, Inc, Okayama, Japan).
The mechanical properties of all structures are those available in the specific literature described in Table 1.
Table 1: Mechanical properties (elasticity modulus (Mpa) and Poisson's coefficient) for each material used on study.
Material Young’s Modulus (E) (Gpa) Poisson's ratios (v) Authors Zircon 205 0.22 (Coelho et al., 2009a) Resin Ciment 18.3 0.3 (Li-li et al. 2006) Cortical bone 13.6 0.26 (Cruz et al., 2009) Cancellous bone 1.36 0.31 (Cruz et al. 2009) Titanium 110 0.25 (Cruz et al. 2009)
Numerical analysis:
The models on Solidworks program were exported to Ansys Workbench 14.0 finite element program (Swanson Analysis Inc., Houston, PA, USA) in the .igs (Initial Graphics Exchange Specification) format for numerical analysis. Immediate loading in MAC, SB and SB + AE was simulated using the friction coefficient of bone-implant interface obtained on in vitro study. In other interfaces, the bonded condition was considered bonded. The convergence analysis to generate FEA mesh was 5%. The loading was performed applying a force on occlusal at 49N was divided into 5 contact points.
Statistical Analysis:
The statistical tests were performed to compare friction coefficient of bone-implant interface with different surface treatments, where the dependent variable was friction and the independent variable was surface treatments and its surface roughness. Statistical analysis was
also used to evaluate titanium roughness surface (MAC, SB and SB + AE) where dependent variable was roughness and the independent variables were titanium and bone surfaces. To ensure the correct statistical analysis, the number of samples were determined. A power of 0.999 was obtained for the cortical bone; 0.989 for the cancellous bone and 0.999 for titanium surface. The statistical test used for both analyzes was ANOVA One-Way and post-hoc Tukey, taking into consideration p <0.05.
Results
Scanning Electron Microscopy (SEM) titanium analysis showed that MAC surface had grooves from the projectile machining. SB surface showed peaks on titanium surface due to aluminum oxide attack on it and surface SB + AE showed higher peaks, due to surface treatment with blasting and acid attack (fig. 02). Regarding the surface roughness (table 2), MAC surface (0.52 ± 0.08 µm) presented the least surface roughness average differing for both SB (0.89 ± 0.08 µm) and SB + AE (0.98 ± 0.13 µm) (p<0.05).
Figure 02. Representative SEM eletron-micrographies of titanium samples before FC measurements: (A and B) (SB + AE); (C and D) (SB); (E and F) (MAC).
The numerical results obtained by tribological analysis in cortical bone showed SB + AE surface with a higher friction coefficient (0.415 ± 0.05) (p<0.05) when compared to SB (0.358 ± 0.03) and MAC surface (0.314 ± 0.04). Considering the cancellous bone the results were similar to cortical bone, where SB + AE surface obtained a higher friction coefficient (0.422 ± 0.05) (p<0.05) compared to both SB (0.384 ± 0.03) and MAC surface (0.362 ± 0.03).
Therefore, in statistical results of tribological analysis shown that friction coefficient of SB + AE and SB surface was similar in cortical and cancellous bone (table 2).
Ra (µm) FC
Cortical Cancellous
MAC 0,52 (A) 0,314 (a) 0,362 (a)
JAT 0,89 (B) 0,358 (b) 0,384 (b)
J+A 0,98 (B) 0,415 (b) 0,422 (b)
Table 2: Friction coefficient and roughness of different surface treatment analyzed.
Regarding biomechanics analyzed through Finite Element Analysis (FEA) (fig. 03), we might observe, in cortical bone, SB + AE surface presented higher bone compression (495,47 MPa) and shear (197,46 MPa). For deformation (10,65 μm) and stress (269,87 MPa) SB + AE surface values presented lower values when compared to SB, which obtained bone compression (432,77 MPa), shear (174,03 MPa), deformation (11,6 μm) and tension (295,24 MPa). For the cancellous bone, SB + AE surface presented lower bone compression (14,62 MPa), shear (11,45 MPa), deformation (9,03 μm) and tension (22,18 MPa) compared to SB with bone compression (17,49 MPa), shear (12,24 MPa), deformation (9,84 μm) and tension (25,76 MPa).
Figure 03. Image of compression, shear, deformation and tension of the differents structures used on the FEA according to the titanium surface treatments
DISCUSSION
The present study demonstrate that friction coefficient between bone-implant interface changed according to different treatment on implant surface. In addition, using different bone types and blood as immersion means, which usually occurs in the surgical site. In this sense, the greatest contribution of our manuscript is that we were able to present that if it changes the friction coefficient due to titanium surface treatments it was able to change the biomechanical behavior of short implants under immediate loading, altering chew stress distribution.
The implant roughness surface, especially of Group SB + AE, seems to have a crucial role to determine the friction coefficient. The implant surface treatments have shown difference between themselves. The surface SB + AE provides a higher friction on bone-implant interface. It occurs because of the different treatments presents on titanium surface, and it had changed your original condition (Nemtoi et al., 2017). In that case, this change of friction coefficient could remove this surface treatment at implant insertion time. In addition, this surface treatment removal can occur osseointegration failures and cause an inflammation on gingiva-bone-implant interface, causing a loss-bone, named peri-implantitis (Senna et al., 2013).
Therefore, to biomechanics factors, higher friction coefficient on SB + AE surface showed a better behavior in relation to other groups as a higher compression in cortical bone, which promote a higher initial implant stability (Rozé et al., 2009) and, by contrast, a smaller deformation and tension on implant surface. On cancellous bone surface SB + AE presented lower values in all the biomechanical criteria evaluated, however, on immediate loading, bone stabilization is performed mostly in cortical bone. The smaller forces and tensions present in cancellous bone is benefic to a better osseointegration process, ensuring the success of short implants under immediate loading (Sotto-Maior et al., 2010).
The Tribological Analysis was shown to be an effective tool and easy to handle for friction coefficient determination between interfaces with fluid presence between surfaces (Bordin et al., 2015). With this tool, it was possible to determine friction coefficient of different surface treatments and bone type and with this coefficient complements FEA program. This analysis, with a friction coefficient closer to the real, enabled a simulation closest to the clinical reality. In this sense, it was possible to note the prosthesis placement in immediate loading for short implants can be used, but clinical trials should be performed for proving your effectiveness when the implant was rehabilitated in immediate loading because in our study it is a reliable simulation of chewing biomechanics. Thus, without any clinical trials it is not
possible say if it was able to realize or not a short implant under immediate loading. However, our study showed the biomechanical benefits of surface treatments under immediate loading and we think clinical trials studies have to be done to demonstrate the effectiveness of short implants on its conditions.
CONCLUSION
Different implant surfaces treatments alter the friction coefficient of titanium-bone interface and interfere in biomechanics of unit short implant under immediate loading.
Acknowledgments
We thank the Signo-Vinces Dental Equipment company, in the name of his Engineer Andreas Reinhard Firzlaff for the donation of titanium samples.
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3- CONCLUSÃO
Os tratamentos de superfície dos implantes são capazes de alterar o CA da interface osso-titânio, interferindo assim, na biomecânica de implantes curtos unitários sob carga imediata.
4- REFERÊNCIAS
Al-Sabbagh M, Bhavsar I. Key local and surgical factors related to implant failure. Dent Clin North Am [Internet]. Elsevier Inc; 2015 Jan;59(1):1–23. Available from: http://dx.doi.org/10.1016/j.cden.2014.09.001
Alvira-González J, Díaz-Campos E, Sánchez-Garcés M-A, Gay-Escoda C. Survival of
immediately versus delayed loaded short implants: A prospective case series study. Med Oral Patol Oral Cir Bucal. 2015 Jul 1;20(4):e480-8.
Bordin D, Cavalcanti IMG, Jardim Pimentel M, Fortulan CA, Sotto-Maior BS, Del Bel Cury AA, et al. Biofilm and saliva affect the biomechanical behavior of dental implants. J
Biomech. 2015 Apr;48(6):997–1002.
Çaglar A, Bal BT, Karakoca S, Aydın C, Yılmaz H, Sarısoy S. Three-dimensional finite element analysis of titanium and yttrium-stabilized zirconium dioxide abutments and implants. Int J Oral Maxillofac Implants. 2011;26(5):961–9.
Chun H, Shin H, Han C-H, Lee S-H. Influence of implant abutment type on stress distribution in bone under various loading conditions using finite element analysis. Int J Oral Maxillofac Implants. 2005;21(2):195–202.
Coelho PG, Granjeiro JM, Romanos GE, Suzuki M, Silva NRF, Cardaropoli G, et al. Basic research methods and current trends of dental implant surfaces. J Biomed Mater Res B Appl Biomater. 2009 Feb;88(2):579–96.
Esposito M, Pellegrino G, Pistilli R, Felice P. Rehabilitation of postrior atrophic edentulous jaws: prostheses supported by 5 mm short implants or by longer implants in augmented bone? One-year results from a pilot randomised clinical trial. Eur J Oral Implantol. 2011;4(1):21–30. Esposito M, Zucchelli G, Barausse C, Pistilli R, Trullenque-Eriksson A, Felice P. Four
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Gao J, Matsushita Y, Esaki D, Matsuzaki T, Koyano K. Comparative stress analysis of delayed and immediate loading of a single implant in an edentulous maxilla model. J Dent Biomech. 2014;5(X):1758736014533982.
Guda T, Ross TA, Lang LA, Millwater HR. Probabilistic analysis of preload in the abutment screw of a dental implant complex. J Prosthet Dent. 2008 Sep;100(3):183–93.
Hanaoka M, Gehrke SA, Mardegan F, Gennari CR, Taschieri S, Del Fabbro M, et al. Influence of Implant/Abutment Connection on Stress Distribution to Implant-Surrounding Bone: A Finite Element Analysis. J Prosthodont. 2014 Oct;23(7):565–71.
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Jayme SJ, Ramalho PR, De Franco L, Jugdar RE, Shibli JA, Vasco MAA. Comparative Finite Element Analysis of Short Implants and Lateralization of the Inferior Alveolar Nerve With Different Prosthesis Heights. J Craniofac Surg. 2015 Nov;26(8):2342–6.
Khraisat A. Influence of abutment screw preload on stress distribution in marginal bone. Int J Oral Maxillofac Implants. 2012;27(2):303–7.
Koirala DP, Singh S V, Chand P, Siddharth R, Jurel SK, Aggarwal H, et al. Early loading of delayed versus immediately placed implants in the anterior mandible: A pilot comparative clinical study. J Prosthet Dent. Editorial Council for the Journal of Prosthetic Dentistry; 2016 Sep;116(3):340–5.
Lang LA, Kang B, Wang R-F, Lang BR. Finite element analysis to determine implant preload. J Prosthet Dent. 2003 Dec;90(6):539–46.
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Nisand D, Renouard F. Short implant in limited bone volume. Periodontol 2000. 2014 Oct;66(1):72–96.
Pessoa RS, Vaz LG, Marcantonio E, Vander Sloten J, Duyck J, Jaecques SVN.
Biomechanical evaluation of platform switching in different implant protocols: computed tomographybased three-dimensional finite element analysis. Int J Oral Maxillofac Implants. 2010;25(5):911–9.
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Santiago Junior JF, Verri FR, Almeida DADF, de Souza Batista VE, Lemos CAA, Pellizzer EP. Finite element analysis on influence of implant surface treatments, connection and bone types. Mater Sci Eng C Mater Biol Appl. Elsevier B.V.; 2016 Jun;63:292–300.
Yazicioglu D, Bayram B, Oguz Y, Cinar D, Uckan S. Stress Distribution on Short Implants at Maxillary Posterior Alveolar Bone Model with Different Bone-to-Implant Contact Ratio: Finite Element Analysis. J Oral Implantol. 2015 Feb 2;27–33.
ANEXOS
Anexo 3: Comprovante de Submissão
20/04/2018 Email – vinicius.santos91@hotmail.com
[ BJOS] Submission Acknowledgement
Altair Antoninha Del Bel Cury <brjorals@fop.unicamp.br>
sex 20/04/2018 17:57
Para:Vinicius Santos <vinicius.santos91@hotmail.com>;
Vinicius Santos:
Thank you for submitting the manuscript, " IMPLANT SURFACE TREATMENT AFFECTS THE BIOMECHANICS OF IMMEDIATE SHORT
IMPLANT LOADING" to Brazilian Journal of Oral Sciences. With the online journal management system that we are using, you will be able to track its progress through the editorial process by logging in to the journal web site:
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If you have any questions, please contact me. Thank you for considering this journal as a venue for your work.
Altair Antoninha Del Bel Cury
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