UNIVERSIDADE FEDERAL DE SANTA CATARINA CENTRO DE CIÊNCIAS DA SAÚDE
PROGRAMA DE PÓS-GRADUAÇÃO EM ODONTOLOGIA
TESE DE DOUTORADO
LEONARDO VIEIRA BEZ
ESTUDO CLÍNICO PROSPECTIVO DA PERFORMANCE CIRÚRGICA E PROTÉTICA DE 170 IMPLANTES COM
CONEXÃO CONE MORSE
FLORIANÓPOLIS 2019
Leonardo Vieira Bez
ESTUDO CLÍNICO PROSPECTIVO DA PERFORMANCE CIRÚRGICA E PROTÉTICA DE 170 IMPLANTES COM
CONEXÃO CONE MORSE
Tese de Doutorado submetida ao Programa de Pós-graduação em Odontologia da Universidade Federal de Santa Catarina para obtenção do título de Doutor em Odontologia.
Área de concentração: Implantodontia
Orientador: Prof. Dr. César Augusto Magalhães Benfatti.
Florianópolis 2019
Ficha de identificação da obra elaborada pelo autor,
através do Programa de Geração Automática da Biblioteca Universitária da UFSC.
Bez, Leonardo Vieira
Estudo clínico prospectivo da performance cirúrgica e protética de 170 implantes com conexão cone morse / Leonardo Vieira Bez ; orientador, Cesar Augusto Magalhães Benfatti, 2019.
41 p.
Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde, Programa de Pós-Graduação em Odontologia, Florianópolis, 2019.
Inclui referências.
1. Odontologia. 2. Implantes dentários. 3. Conexão implante dentário cone morse. 4. Implantes dentários - Fatores de risco. 5. Implantes dentários - Sobrevivência. I. Benfatti, Cesar Augusto Magalhães. II. Universidade Federal de Santa Catarina. Programa de Pós-Graduação em Odontologia. III. Título.
Leonardo Vieira Bez
ESTUDO CLÍNICO PROSPECTIVO DA PERFORMANCE CIRÚRGICA E PROTÉTICA DE 170 IMPLANTES COM
CONEXÃO CONE MORSE
Este Trabalho Conclusão de Curso foi julgado adequado para obtenção do Título de “Doutor” e aprovado em sua forma final pelo Programa de
Pós-Graduação em Odontologia. Florianópolis, 27 de março de 2019.
________________________ Prof. Dr.ª Elena Riet Correa Riveiro
Coordenadora do curso Banca Examinadora:
________________________ Prof. Dr. César A. M. Benfatti
Orientador
Universidade Federal de Santa Catarina
________________________ Prof. Dr. Ricardo de S. Magini Universidade Federal de Santa Catarina
________________________ Prof. Dr.ª Ariadne C.C. da Cruz Universidade Federal de Santa Catarina
________________________ Prof. Dr. Bernardo Born Passoni
Este trabalho é dedicado á minha família, em especial à minha foi filha Laís.
AGRADECIMENTOS
À DEUS, somente com Fé chegamos aos nossos objetivos. Sem ELE não somos nada.
Aos meus grandes mestres César Benfatti e Ricardo Magini, Deus sempre coloca as pessoas certas no nosso caminho. Vocês são o maior exemplo de sinceridade, amizade, sabedoria e caráter. Não tenho palavras para descrever o quanto sou grato a vocês por todo meu caminho na Pós-Graduação.
“HERÓIS são aqueles que se distinguem por seus valores, por
suas ações extraordinárias e principalmente por feitos brilhantes. Aqueles que são condecorados por suas ações corajosas, pelo seu caráter magnânimo, por comportamentos altruístas”. Hoje tenho
certeza absoluta que vocês são meus heróis de carne e osso.
À minha filha Laís, razão de tudo na minha vida. És o verdadeiro significado do AMOR. Sem tua presença este dia seria impossível.
Ao meu pai, Léo, por me colocar no caminho da odontologia e sempre ser um exemplo de profissional e caráter.
Aos meus avós Gilberto (in memorian) e Lídia, pelos conselhos, pelo exemplo de longevidade e felicidade. “Vózinha” muito obrigado por tudo.
Aos meus familiares, por entender minhas ausências, pelo apoio e aprendizado constante que tenho no convívio com vocês.
Aos meus tios e tias por todo carinho e acolhimento nesses anos. Em especial, Gilberto Vieira Filho (tio Giba), onde morei por alguns anos e tive os melhores exemplos de como ser uma pessoa correta, honesta, batalhadora e feliz.
À colega e brilhante profissional Carolina Morsh, não tenho palavras para descrever o quanto sou grato por tudo que fizeste. Sem você este trabalho não existiria.
Aos meus colegas de Pós-Graduação, pela amizade, dedicação, colaboração e pelos bons momentos compartilhados.
Ao CEPID/UFSC, local onde fiz toda minha formação acadêmica, da graduação até o doutorado. Posso afirmar que é minha segunda casa.
Às funcionárias do CEPID, em especial à Silvane (Sil), pela dedicação, competência e atendimento a tantos pedidos de ajuda.
A todos os alunos de graduação e Pós Graduação, pela compreensão, dedicação e incentivo durante todos os anos da minha formação.
Aos pacientes que contribuíram para a minha formação, pela confiança creditada, paciência e carinho durante a realização dos trabalhos.
RESUMO
A proposta deste estudo foi avaliar a performance clínica de 170 implantes livre de parafusos através dos seguintes parâmetros cirúrgicos e protéticos: taxa de sobrevivência dos implantes, afrouxamento/fratura do pilar protético, afrouxamento/fratura do parafuso protético, lascamento/fratura da cerâmica, fratura da infraestrutura protética, perda de retenção/decimentação, em diferentes aplicações clínicas, tais como coroas unitárias, próteses parciais fixas e próteses fixas totais. Entre maio de 2017 e julho de 2018, pacientes encaminhados ao Centro de Ensino e Pesquisas em Implantes Dentários (CEPID) para tratamento com implantes livres de parafusos com idade acima de 18 anos, boa saúde sistêmica e oral foram incluídos no estudo. Após 12 semanas de cicatrização dos implantes instalados em mandíbula e 16 semanas para os implantes instalados na maxila, os pacientes foram chamados novamente para reabilitação protética. Todos os pacientes foram convocados para novos exames clínico, radiográfico e protético a cada 6 meses. O implante foi utilizado como unidade de avaliação para todos os parâmetros de análise. As restaurações envolveram 109 reconstruções fixas em função por pelo menos 6 meses. Poucas complicações protéticas foram relatadas (6,55%). 20 implantes foram reabilitados com próteses cimentadas, dos quais uma única coroa sofreu perda de retenção/decimentação. Dos 148 implantes reabilitados com próteses retidas por parafusos, 6,76% sofreram afrouxamento do parafuso protético. A incidência de lascas na cerâmica foi de 1,8%. A taxa de sobrevivência cumulativa do implante foi de 98,2%. Concluiu-se que o uso de implantes sem parafusos representa um procedimento bem-sucedido para a reabilitação de implantes, com uma taxa de sobrevivência cumulativa do implante de 98,2% e uma incidência muito baixa de complicações protéticas (6,55%) devido a uma alta estabilidade mecânica.
Palavras-chave: Sobrevivência. Fatores de risco. Complicações. Implantes dentários. Conexão implante dentário cone morse.
ABSTRACT
The purpose of this study was to evaluate the clinical performance of 170 screw free implants through the following surgical and prosthetic parameters: implant survival rate, abutment loosening/fracture, screw loosening/fracture, ceramic chipping/fracture, fracture of framework, loss of retention/decementation, in different clinical applications, such as single crowns, fixed partial prostheses and fixed full-arch prostheses. Between May 2017 and July 2018, patients referred to the Center on Education and Research on Dental Implants for treatment with screw free implants with age >18 years, good systemic and oral health were considered for inclusion in this study. After 12 weeks of healing for implants placed in the lower jaw and 16 weeks for those placed in the upper jaw, the patients were recalled for rehabilitation. All patients were recalled for clinical, radiographic, and prosthetic examination every 6 months. The implant was used as the unit of evaluation to all parameters of analysis. Restorations involved 109 fixed reconstructions in function for at least 6 months. A few prosthetic complications were reported (6,55%). 20 implants were rehabilitated with cemented prostheses, from those one single crown suffered loss of retention/decementation. From 148 implants rehabilitated with screwed retained prostheses, 6,76% suffered prosthetic screw loosening. Incidence of ceramic chipping was 1,8%. The cumulative implant survival rate was 98,2%. The use of screw free implants represents a successful procedure for implant rehabilitation, with a cumulative implant survival rate of 98,2% and a very low incidence of prosthetic complications (6,55%) due to a high mechanical stability.
Keywords: Survival. Risk factors. Complications. Dental implants. Morse Taper Dental Implant-Abutment Connection.
LISTA DE TABELAS
LISTA DE ABREVIATURAS E SIGLAS CBCT: Cone beam computed tomography
CEPID: Centro de Ensino e Pesquisas em Implantes Dentários CI: Confidence interval
EAO: European Association for Osseointegration FDPs: Fixed dental prosthesis
FFAs: Fixed full-arch prostheses FPPs: Fixed partial prostheses g: Gram h: Hours mg: Milligram mm: Millimeter N: Newton SCs: Single crowns
SUMÁRIO 1 INTRODUÇÃO... 21 2 PERGUNTAS DA PESQUISA... 23 2.1 PERGUNTA PRINCIPAL... 23 2.2 PERGUNTAS SECUNDÁRIAS... 23 3 JUSTIFICATIVA... 24 4 OBJETIVOS... 25 4.1 OBJETIVO GERAL... 25 4.2 OBJETIVOS ESPECÍFICOS... 25 5 ARTIGO EM INGLÊS... 26 5.1 ABSTRACT……….. 26 5.2 INTRODUCTION………. 27
5.3 MATERIAL AND METHODS………... 28
5.3.1 Implant Design………..….. 29
5.3.2 Surgical and restorative procedure……… 29
5.3.3 Statistical analysis... 31 5.4 RESULTS………... 31 5.5 DISCUSSION………. 32 5.6 CONCLUSION……….. 34 5.7 REFERENCES………... 34 APÊNDICE A... 39
1 INTRODUÇÃO
Uma opção de tratamento viável e previsível para a reabilitação de arcadas desdentadas é a prótese fixa sobre implante (FDP)1. É presumível que, com a expectativa de vida próspera, as reabilitações com implantes precisem sobreviver por muitos anos2 e a rotina clínica do uso de qualquer sistema de implante deve ser baseada na avaliação do comportamento de um sistema específico através de exames clínicos de acompanhamento3. Em uma revisão sistemática sobre próteses implantossuportadas, Pjetursson et al. relataram uma taxa estimada de sobrevida de FDP metalocerâmicas de 96,4% após 5 anos e 93,9% após 10 anos em função e apenas 66,4% dos pacientes estavam livres de complicações após 5 anos2.
Em um estudo clínico4 que avaliou 2.506 implantes de conexão cone morse, a taxa de sobrevivência cumulativa dos implantes foi de 98,23%. Um implante pode ser classificado como bem-sucedido quando preencher todos os fatores críticos de sucesso ausência de: dor/sensibilidade, supuração/exsudação, mobilidade de implantes clinicamente detectável, radiolucidez peri-implantar contínua, complicações protéticas e; distância entre o ombro do implante e o primeiro contato osso-implante visível inferior a 1,5 mm após 12 meses de carga funcional, e não excedendo 0,2 mm de perda óssea para cada ano seguinte3.
Apesar do alto sucesso e previsibilidade das reabilitações implantossuportadas, muitos relatos de alta incidência de complicações protéticas, como fraturas de parafusos ou pilares, fraturas do cimento (perda de retenção), fraturas ou deformações da infraestrutura ou coroas protéticas, perda da restauração do orifício de acesso ao parafuso, afrouxamento do parafuso ou do pilar protético foram publicados2.
Conexões tipo parafuso são as mais comumente usadas5,6, entretanto, o parafuso é um problema comum de próteses implantossuportadas (terceira complicação técnica mais comum)2. O parafuso pode afrouxar ou fraturar quando as cargas oclusais excedem a pré-carga e baixas forças mastigatórias podem potencialmente levar ao afrouxamento gradual do pilar ou conexão pilar-coroa7,8. A segunda falha técnica mais comum relacionada à prótese sobre implante é a perda da restauração do orifício de acesso, com taxa de 5,4% após 5 anos de acompanhamento e a complicação técnica mais comum foi a fratura do material de recobrimento (acrílico, cerâmica ou compósito)2.
Após 5 anos, 13,5% das FDPs (95% CI: 8,5% - 20,8%) apresentavam fraturas menores ou maiores do material de revestimento. No entanto, de acordo com a terceira conferência de consenso da Associação Européia para Osseointegrassão (EAO), a complicação técnica mais comum foi a soltura de parafusos ou pilares9, corroborando com os outros resultados que mostraram 8,9% de falhas de parafusos em próteses instaladas sobre pilares protéticos10.
Em um esforço para melhorar a estabilidade da conexão protética e reduzir ainda mais a incidência de complicações mecânicas e biológicas, foram introduzidas conexões cônicas. Uma conexão implante-pilar sem parafuso (conexão Morse pura, implante com travamento-cônico) foi introduzida como alternativa aos sistemas de pilares aparafusados. Esses sistemas de implantes são compostos por um implante e um pilar unidos por uma conexão Cone Morse, que induz uma união autotravante entre as partes componentes. O parafuso de ligação é eliminado e apenas o atrito entre as superfícies do implante e do pilar garante a estabilidade dos componentes mecânicos. Isto resulta em uma junção biomecanicamente mais estável, com uma menor folga do que as conexões tipo parafuso, capazes de resistir a cargas excêntricas e momentos fletores e reduzir a infiltração microbiana11,12,13. Um estudo prospectivo de 10 anos de acompanhamento sobre as taxas de sobrevida e complicações de restaurações fixas suportadas por implantes isentos de parafusos confirmou com uma taxa de 88,6% que esse sistema implante-pilar parece ser um procedimento de sucesso para reabilitação dentária com incidência muito baixa de complicações mecânicas (0,4%) e técnicas (3,2% )14. Embora a literatura assegure a eficácia deste tipo de conexão do implante, existe uma falta na avaliação de parâmetros cirúrgicos e protéticos em diferentes aplicações clínicas. Portanto, o objetivo deste estudo é avaliar o desempenho clínico de 170 implantes sem parafusos (Arcsys FGM®, Joinville, Brasil) através dos seguintes parâmetros cirúrgicos e protéticos: taxa de sobrevivência do implante, soltura/fratura do pilar protético, afrouxamento/fratura do parafuso protético, lascamento/fratura da cerâmica, fratura da infra-estrutura protética, perda de retenção/decimentação das próteses, em diferentes aplicações clínicas, como coroas unitárias (SCs), próteses parciais fixas (FPPs) e próteses fixas totais (FFAs).
2 PERGUNTAS DE PESQUISA
2.1 PERGUNTA PRINCIPAL
Implantes com conexões protéticas sem parafusos (Cone Morse puro) possuem uma boa performance clínica cirúrgica e protética?
1.2 PERGUNTAS SECUNDÁRIAS
1 Qual é a taxa de sucesso dos implantes com conexões protéticas sem parafusos (Cone Morse puro)?
2 Qual a taxa de complicações protéticas, tais como: soltura/fratura do pilar protético, afrouxamento/fratura do parafuso protético, lascamento/fratura da cerâmica, fratura da infra-estrutura protética, perda de retenção/decimentação das próteses, em diferentes aplicações clínicas, como coroas unitárias (SCs), próteses parciais fixas (FPPs) e próteses fixas totais (FFAs)?
3 JUSTIFICATIVA
Os implantes dentários têm sido utilizados com sucesso em reabilitações orais há muitos anos. São uma opção de tratamento viável e previsível para reabilitações com próteses fixas unitárias, parciais e totais.
As conexões hexagonais dos implantes são as mais conhecidas, estudadas, com inúmeras publicações e demonstram problemas relacionados a estabilidade da união implante-pilar protético, micro movimentações, fratura e afrouxamento de parafusos, infiltração microbiana, entre outros.
Para solucionar esses problemas foram desenvolvidas as conexões cônicas para implantes, dentre elas, as conexões cone morse puro, as quais não necessitam de parafuso na união implante-pilar protético e trazem mais estabilidade ao sistema, evitam micro movimentações, diminuem consideravelmente a infiltração microbiana, resultando assim em mais saúde dos tecidos periimplantares.
Embora a literatura assegure a eficácia deste tipo de conexão do implante, existe uma falta de estudos que avaliem os parâmetros cirúrgicos e protéticos em diferentes aplicações clínicas, justificando assim, este estudo.
4 OBJETIVOS
4.1 OBJETIVO GERAL
Avaliar o desempenho clínico de 170 implantes sem parafusos (conexão Cone Morse puro) através de parâmetros cirúrgicos e protéticos, reabilitados com coroas unitárias (SCs), próteses parciais fixas (FPPs) e próteses fixas totais (FFAs).
4.2 OBJETIVOS ESPECÍFICOS
1 Definir a taxa de sobrevivência dos 170 implantes instalados; 2 Verificar a porcentagem de soltura/afrouxamento dos pilares
protéticos;
3 Observar a taxa de lascamento/fratura das coroas cerâmicas instaladas a no mínimo 6 meses em função;
4 Investigar se existiram fraturas nas infra-estruturas protéticas; 5 Averiguar a perda de retenção/decimentação das próteses sobre
5 ARTIGO EM INGLÊS
PROSPECTIVE CLINICAL STUDY OF SURGICAL AND PROTETIC PERFORMANCE OF 170 IMPLANTS WITH MORSE
TAPER CONNECTION 5.1 ABSTRACT
Objective: The purpose of this study was to evaluate the clinical performance of 170 screw free implants through the following surgical and prosthetic parameters: implant survival rate, abutment loosening/fracture, screw loosening/fracture, ceramic chipping/fracture, fracture of framework, loss of retention/decementation, in different clinical applications, such as single crowns, fixed partial prostheses and fixed full-arch prostheses.
Materials and methods: Between May 2017 and July 2018, patients referred to the Center on Education and Research on Dental Implants for treatment with screw free implants with age >18 years, good systemic and oral health were considered for inclusion in this study. After 12 weeks of healing for implants placed in the lower jaw and 16 weeks for those placed in the upper jaw, the patients were recalled for rehabilitation. All patients were recalled for clinical, radiographic, and prosthetic examination every 6 months. The implant was used as the unit of evaluation to all parameters of analysis.
Results: Restorations involved 109 fixed reconstructions in function for at least 6 months. A few prosthetic complications were reported (6,55%). 20 implants were rehabilitated with cemented prostheses, from those one single crown suffered loss of retention/decementation. From 148 implants rehabilitated with screwed retained prostheses, 6,76% suffered prosthetic screw loosening. Incidence of ceramic chipping was 1,8%. The cumulative implant survival rate was 98,2%.
Conclusions: The use of screw free implants represents a successful procedure for implant rehabilitation, with a cumulative implant survival rate of 98,2% and a very low incidence of prosthetic complications (6,55%) due to a high mechanical stability.
Keywords: Survival; risk factors; complications; dental implants; screw free implant; morse-taper connection implants.
5.2 INTRODUCTION
A viable and predictable treatment option for the rehabilitation of edentulous arches is the implant-supported fixed dental prosthesis (FDPs)1. It is presumable, that with the prosperous life expectancy, implant reconstructions need to survive for many years2 and the clinical routine of the use of any implant system should be based on the evaluation of the behavior of a specific system through clinical follow-up examinations3. In a systematic review on implant-supported prostheses, Pjetursson et al. reported an estimated survival rate of metal-ceramic FDPs of 96.4% after 5 years and 93,9% after 10 years in function and only 66.4% of the patients were free of any complications after 5 years2.
In a clinical study4 that evaluated 2.506 Morse taper connection implants, the cumulative implant survival rate was 98,23%. An implant can be classified as successful when fill all the critical success factors: absence of pain/sensitivity, suppuration/exudation, clinically detectable implant mobility, continuous peri-implant radiolucency, prosthetic complications and; distance between the implant shoulder and the first visible bone-to-implant contact less than 1.5 mm after 12 months of functional loading, and not exceeding 0.2 mm of bone loss for each following year3. Despite the high success and predictability of implant-supported rehabilitations, many reports of a high incidence of prosthetic complications, such as fractures of screws or abutments, fractures of the luting cement (loss of retention), fractures or deformations of the framework or veneers, loss of the screw access hole restoration, screw or abutment loosening have been published2.
Screw-type connections are most commonly used5,6, however, the screw is an ordinarily problem of implant-supported prostheses (third most common technical complication)2. Screw can loosen or fracture when occlusal loads exceed the preload and lower masticatory forces may potentially lead to gradual loosening of the implant-abutment, crown-abutment connection7,8. The second most common technical failure related to implant prostheses is the loss of the screw access hole restoration with a rate after 5-year follow-up of 5.4% and the most common technical complication was the fracture of the veneer material (acrylic, ceramic, or composite)2. After 5 years, 13.5% (95% CI: 8.5%– 20.8%) of the FDPs had minor or major fractures of the veneering material. Notwithstanding, according to the third EAO consensus conference, the highest common technical complication was screw or
abutment loosening9, corroborating with the other results with 8.9% of screw failures in prostheses placed over abutments10.
In an effort to better stabilize the prosthetic connection and further reduce the incidence of mechanical and biological complications, conical connections have been introduced. A screw free implant-abutment connection (pure Morse taper, locking-taper implant) has been introduced as an alternative to screw-retained abutment systems. These implant systems are composed of an implant and an abutment joined together by a Morse taper, which induces a self-locking mating between the component parts. The connecting screw is eliminated and only the friction between implant and abutment surfaces guarantees assembly of the mechanical components. This result in a tight junction biomechanically more stable, with a minor gap than screw-type connections, capable of resisting eccentric loads and bending moments and reducing microbial penetration11,12,13.
A 10 year follow-up prospective study about the survival and complication rates of fixed restorations supported by screw free implants confirmed a rate of 88.6% of successful of this implant-abutment system with only 0.4% incidence of mechanical and 3.2% technical complications14. Although the literature assures the efficacy of this type of implant connection, there is a lack on the evaluation of surgical and prosthetics parameters in different clinical applications. Therefore, the aim of this observational study was to evaluate the clinical performance of 170 screw free implants (Arcsys FGM®, Joinville, Brazil) through the following surgical and prosthetic parameters: implant survival rate, abutment loosening/fracture, screw loosening/fracture, ceramic chipping/fracture, fracture of the framework, loss of retention/decementation, in different clinical applications, such as single crowns (SCs), fixed partial prostheses (FPPs) and fixed full-arch prostheses (FFAs).
5.3 MATERIAL AND METHODS
The study protocol was approved by the research Ethical Committee Protocol no 2.079.136. The study protocol was explained to each subject, and signed informed consent was obtained.
Between May 2017 and July 2018, all patients referred for treatment with dental implants were considered for inclusion in this study. Inclusion criteria were age >18 years, good systemic and oral health. Exclusion criteria consisted of poor oral hygiene, active periodontal
infections or other oral disorders, current pregnancy, uncontrolled diabetes mellitus, or heavy smoking habit (> 10 cigarettes/day).
5.3.1 Implant Design
Screw free connection implants (Arcsys FGM®, Joinville Brazil) were used. The inner walls design of these pure Morse taper implant presents a 1.5 degrees angulation, which eliminates screw mechanical retention. The implant-abutment connection is based on the principle defined as “cold welding”. The connecting screw is eliminated and assembly of the mechanical components is guaranteed only by friction between implant and the microscopic irregularity of the abutment surfaces15,16. These implant systems provide the possibility of abutment angulation between 0 and 20 degrees, according to each clinical case due to a solid body (without a passing screw) and a more resistant material (Stainless Steel). 5.3.2 Surgical and restorative procedure
Before implant placement, a complete oral examination was carried out for each participant enrolled in the study. Patients received appropriate treatments and oral hygiene instruction. Cone beam computed tomography (CBCT) was obtained to assess the width and thickness of each implant site, the density of the cortical and cancellous bone, and the relationship with important anatomical structures. Based in the diagnostic wax-up, surgical guides were manufactured.
Patients were divided in groups according to clinical requirement: delayed implant placement, immediate implant placement, implant placement with bone grafting procedures, conventional loading and immediate loading. Parameters included at the time of implant placement were: the tooth position, moment of implant placement, implant length and diameter, torque, when bone grafting was performed, implant loading protocol.
All patients received antibiotic prophylaxis with oral amoxicillin (2g) one hour before the surgery and used 0.12% chlorhexidine mouthwash for 1 minute immediately before starting the intervention. All surgeries were performed under local anesthesia. For non-grafted cases, a minimally invasive full-thickness flap was elevated. When an immediate implant was placed, flapless and minimal traumatic extraction of a failing tooth was performed and the gap was filled with particulate bone graft. Preparation of implant sites was carried out following manufacturer recommendations, under constant irrigation, with implants
positioned 2mm below the bone crest level. When a torque >32N was obtained, the implant could be immediate loaded with a provisional prosthesis. When the implant was not immediate loaded the cover cap was positioned and the full thickness flap was sutured over it. All patients continued to administer the oral antibiotics, 2g of amoxicillin each day for more 6 days. Post-operative pain was controlled by administering 100mg nimesulide every 12h for 3 days. Detailed instructions about postoperative care were given, mouthrinses with 0.12% chlorhexidine was administered for 10 days. Suture removal was performed at 7–10 days.
After 12 weeks of healing for implants placed in the lower jaw and after 16 weeks for those placed in the upper jaw, the patients were recalled to rehabilitate the implants with single crowns (SCs), fixed partial prostheses (FPPs), or fixed full-arch prostheses (FFAs). A second-stage surgery was performed to obtain access to the underlying implants. All bone or soft tissue interferences in and around the implant were removed and healing abutments were placed. After 2 weeks, the abutments were selected, angulated when needed according to the clinical case, placed and activated with 3 seating taps in the implant long axis with the handle/mallet, so the definitive restorations could be fabricated.
Full-arch prostheses were fabricated with acrylic resin with a metal framework, SCs and FPPs were metalloceramic. When the prosthesis was cemented, the cementation was performed with zinc phosphate cement (SS White Duflex, Rio de Janeiro, Brazil), when it was screwed, the torque of the prosthetic screw was of 10N, following manufacturer recommendations.
All patients were recalled for clinical, radiographic, and prosthetic examination every 6 months. The cumulative implant survival rate was investigated and careful attention was dedicated to the analysis of prosthetic complications (abutment loosening, abutment fracture, screw loosening, screw fracture, loss of retention/decementation, ceramic chipping/fracture, fracture of the framework). All these mechanical complications were carefully registered, and managed during the follow-up visit. An implant has been classified as a survival implant when it was still in function at the last clinical e radiographic control session. An implant was considered failed in cases in which the fixture was removed or in case of lack of osseointegration of the fixture with mobility. The implant survival rate was expressed as a percentage of losses related
with the total amount of implant installed. The implant was used as the unit of evaluation to all parameters of analysis.
5.3.3 Statistical analysis
For statistical analysis of the results, a statistical software package (Stata version 13.0, StatCorp., College Station, TX, USA) was used. Descriptive statistics were used to describe the distribution of patients, implants and restorations, for calculating the incidence of implant failures and prosthetic complications. Comparative analysis of parameters with normal distributions was performed with Student T Test and variance one way ANOVA. For the comparison of parameters without normal distributions, Mann-Whitney U and Kruskal Wallis tests were used. The results were assessed with 95% confidence intervals and the significance level was set to .05.
5.4 RESULTS
A total of 55 patients fulfilled the inclusion criteria and were included in the study. In total, 170 screw free implants were placed. From those, 61%, 104 implants, were placed in the maxilla (41 in the anterior region and 63 in the posterior region), and 39%, 66 implants, in the mandible (10 in the anterior region and 56 in the posterior region). The implant length was >5mm in approximately 96% and the diameter >3.3mm in approximately 73% of the total amount of implants placed. Information about frequencies and confidence interval of all variables have been summarized in Table 1. In 25% of sites, bone regeneration was performed at the moment of implant placement, including 11 GAPs filled when an implant was immediate placed. Only 13 implants were immediate loaded (8 in the anterior maxilla), even with a torque mean of 42N.
The restorations involved 109 fixed reconstructions (89 SCs and 20 multiple prostheses) in function for at least 6 months. A few prosthetic complications were reported (6.55%). Twenty implants were rehabilitated with cemented prostheses, from those 1 SC suffered loss of retention/decementation. From 148 implants rehabilitated with screwed retained prostheses, 6.76%, 10 SCs, suffered prosthetic screw loosening. Ceramic chipping/fracture occured in 3 screw retained SCs (1.8%). All mechanical complications were reported in the posterior area. It is
important to highlight that it was not reported any abutment loosening or fracture, even when it was angulated.
The present study showed a cumulative implant survival rate of 98.2%, with 3 loosened implants in the posterior area (2 in the maxilla and 1 in the mandible). Two implants were classified as ‘‘early failures,’’ showing clinical mobility caused by lack of osseointegration in the healing period and one as "late failure" because it was loosened after abutment activation. None of the loosened implants was immediate loaded.
Twenty implants were rehabilitated with cemented prostheses, from those 1 SC suffered loss of retention/decementation (0.5%). From 148 implants rehabilitated with screwed retained prostheses, 6.76%, 10 SC, suffered prosthetic screw loosening. Ceramic chipping/fracture occured in 3 screw retained SCs (1,8%). No abutment, screw, framework fracture and abutment loosening was observed, even when folded abutments were used.
5.5 DISCUSSION
The present study showed a cumulative implant survival rate of 98.2%, which is in accordance with the results found in other clinical follow-up17, that also evaluated pure Morse taper connection implants used in different prosthetic applications. The overall cumulative implant survival rate of 1920 implants evaluated was 97.5%, with 1884 implants still in function after a period of 4 years of functional loading. Another study from the same group evaluated 2549 implants and showed an implant survival rate of 98.23%, with 2506 implants still in function over a period of 6 years4. These results are in agreement with those reported in several other clinical studies2,5,14,19,20,21.
The implant-abutment connection system used in this study is a pure Morse taper, composed of a fixture and an abutment joined together by friction due to a 1.5 degrees angulation of the implant inner walls. This implant-abutment design ensures a high mechanical stability when compared with the external hexagonal connections17. With a minor microgap size, minimize the biofilm penetration and risk of abutment loosening, resulting in better clinical and biological performance18. A few prosthetic complications were reported in this prospective study (6.55%). This result is in accordance with the study of Wittneben et al., 2013 that also observed a low prosthetic-related failure rate (4.5%)22. The most frequent complication in the current study was screw
loosening (6.76%) in single crowns, which is in agreement with the third EAO consensus conference. The highest common technical complication in single crowns on implants was screw or abutment loosening9, corroborating with the results found in the study of Morsch et al., 201510 with 8.9% of screw failures in prostheses placed over abutments and Priest, 1999 with 7.1%23.
Regarding implant supported SCs and FDPs, a clinical study22 observed a cumulative incidence of occlusal screw loosening of 2.57%, the second most recurrent complication after a mean exposure time of 10.75 years. In a 5-year follow-up study, this technical complication was the third most common with 5.3% rate2. The incidence of screw loosening in the present study was only in SCs, corroborating with the study that found highest incidence of screw loosening in SCs than FDP21.
The second most recurrent mechanical complication was ceramic chipping/fracture that occured in 3 screw retained SCs (1.8%). The occlusal access hole to the screw interrupts the structural continuity of porcelain resulting in an area of minor resistence and fragility which may result in fracture24, and in other study this complication was the most frequent22. Mangano14 observed an incidence rate of 1.2% which is in accordance with the current study and a systematic review with 1.62% per 100 FDPs in a follow-up of five years2. An incidence of 5% of decementation was observed in the present study, according to another clinical follow-up, with 2.7%25.
In the current study, none abutment loosening and/or fracture was observed even with angulation of some abutments accordingly with the clinical case. This result is in agreement with other clinical studies that evaluated pure Morse taper connection26,27,28,29,30. In a study with 15 years follow-up, a very low incidence (1.5%) of prosthetic complications was registered. Regarding the mechanical complications, only 3 were registered and consisted of abutment loosening13. In addition, other researches are in agreement with a low rate (0.3 to 1.5%) of abutment loosening4,5,14,17,25,31,32,33,34. Fracture of pure Morse taper connections abutments was related in other clinical studies. Two (0.5%) fractures were imputed to abutments placed in the posterior region34, another study related 3 fractures with 1.0% rate35. In the current study, none abutment presented fracture, even when folded abutments were used. Framework or screw fracture was not observed, as well, corroborating with other studies13,26,31,28,25,14,32,4,17,33.
5.6 CONCLUSION
The use of screw free implants represents a successful procedure for implant rehabilitation, with a cumulative implant survival rate of 98,2% and a very low incidence of prosthetic complications (6.55%) due to a high mechanical stability. Thus, the results of this study reinforce a clinical use of the implants with pure morse-taper connection.
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APÊNDICE A
Table 1 - Frequencies and confidence interval of variables.
Proportion (%) *α 0,05% Region (n= 170) Upper anterior 24.1 (18.2; 31.2) Upper posterior 37.1 (30.1; 44.6) Lower anterior 6.0 (03.2; 10.6) Lower posterior 32.9 (26.2; 40.4) Installation time (n= 170) Up to six months 0 0 Up to one year 30.0 (23.5; 37.4)
More than a year 70.0 (62.6; 76.5)
Diameter of the implant (n= 170)
3.3mm 27.0 (20.9; 34.3)
>3.3mm 72.9 (65.7; 79.1)
Length of the implant (n= 170)
5mm 4.1 (02.0; 08.4) >5mm 95.9 (91.6; 98.0) Immediate installation (n= 170) No 85.9 (79.7; 90.4) Yes 14.1 (09.6; 20.3) Regeneration (n= 170) No 74.7 (67.6; 80.7)
Yes 25.3 (19.3; 32.4) Immediate loading (n= 170) No 92.3 (87.1; 95.5) Yes 7.7 (04.5; 12.9) Time loading (n= 168) Up to six months 0 -
More than a year 100 -
Type of prosthesis (n= 168) Single 53.0 (45.3; 60.5) Bridge 47.0 (39.5; 54.7) Type of prosthesis (n= 168) Screwed 88.1 (82.2; 92.2) Cemented 11.9 (07.8; 17.8) Type abutment (n= 130) Foldable 66.2 (57.5; 73.9) No foldable 33.9 (26.1; 42.5) Mobility (n= 168) No 100 - Yes - Abutment loss (n= 168) No 100 - Yes - Decementation (n= 20) No 95.0 (67.7; 99.4) Yes 05.0 (00.6; 32.3)
Screw loosening (n= 148) No 93.2 (87.8; 96.4) Yes 06.8 (03.6; 12.2) Screw fracture (n= 148) No 100 - Yes - Ceramic chipping (n= 168) No 98.2 (94.6; 99.4) Yes 1.8 (00.6; 05.4) Framework fracture (n= 168) No 100 - Yes - Abutment fracture (n= 168) No 100 - Yes - Implant loss (n= 170) No 98.2 (94.6; 99.4) Yes 1.8 (00.6; 05.4) *α: significance level Fonte: Autor (2019).
