Effect of clinical and laboratory techniques of cementation on the assessment of marginal and internal fit of prosthetic elements

Aim: The aim of this in vitro study was to compare machine and manual cementation of prosthetic elements by measuring internal and marginal fits. Methods: Eighteen anatomic prefabricated abutments were used to manufacture zirconia copings in the Ceramill (n=9) and Lava systems (n=9). The copings were cemented with a fluid consistency addition silicone using a machine (n=18) and manually (n=18) according to the replica technique. They were then cut in the buccal-palatal and mesial-distal directions. The film thickness was photographed using an optical microscope and measured in the internal and marginal regions. The data collected were analyzed by repeated measures ANOVA and Bonferroni's multiple comparison test (∂=.05). The Bland-Altman test was performed to evaluate the agreement between the methods. Results: In the evaluation of the internal and marginal misfits, the mean values observed for the cementation performed with the aid of a machine and manually, were as follows: angular regions, 76.7 µm and 76.2 µm; linear regions, 60.6 µm and 60.7 µm; incisal region, 144.8 µm and 145.2 µm; marginal region, 40.1 µm and 40.2 µm; and overall mean, 80.4 µm and 80.6 µm, respectively. No significant differences were found between the 2 methods, for any of regions and systems (P>.05). The Bland-Altman test showed agreement between the methods (P>.05) and that the limits of agreement found were clinically acceptable. Conclusions: Within the limitations of this in vitro study, we can conclude that cementation using manual techniques or mechanical aid produces the same cement films

Confecção de guia multifuncional para planejamento de reabilitação implantossuportada: relato de caso / Preparation of a multifuncional guide for the planning of implant-supported rehabilitations: case report / Elaboración de una guía multifuncional para la planificación de rehabilitación implantosoportada: informede caso

Introdução:Em busca da estética e da função mastigatória,é cada vez mais crescente aprocurapor reabilitações implantossuportadas. O guia multifuncional surgepara orientar a disponibilidade óssea e contribuir no planejamento da instalação tridimensional dos implantes, seguindo os princípios do planejamento reverso.Objetivo:Descrever, por meio de um caso clínico, a possibilidade de obtenção de resultados de excelente previsibilidade em coroas unitárias implantossuportadas, por meio do uso de guias multifuncionais, no planejamento do início ao fim de tratamento.Relato decaso:Paciente A.M.F, 44 anos, sexo feminino, compareceu à clínica de Prótese dentária do Departamento de Odontologia/UFRN com queixa de insatisfação da sua prótese removível e harmonia do sorriso. Ao exame clínico e radiográfico, observou-se ausência do elemento 12, apresentando um espaço interoclusal de 5mm e distância médio-distal de 7mm. Foi confeccionado o guia em resina acrílica, o qual foi preenchido o espaço desdentado com um dente de estoque. Em seguida, o dente deste guia teve seu centro perfurado com uma broca esférica para peça reta na região de cíngulo e com isso, preenchida com guta percha em bastão. Após isso, o paciente foi encaminhado para realizar uma tomografia computadorizada cone beam com o guia multifuncional em posição.As imagens obtidas permitiram o planejamento para instalação do implante, como inclinação e posicionamento favorável, bem como ausência de disponibilidade óssea na região. Além disso, o guia funcionou em outras etapas do tratamento da paciente, como na fase provisória.Conclusão:Os guias auxiliam em diversas fases do tratamento e permitem maior previsibilidade dos resultados em reabilitações protéticas unitárias implantossuportadas, apresentando-se como um dispositivo promissorpara ocorreto posicionamento do implante (AU).

Introduction:In search of esthetics and improved masticatory function, the demand for implant-supported rehabilitation is increasing. Multifunctional guides emerge to assess bone availability and help plan the three-dimensional installation of implants, following the principles of reverse planning. Objective:To describe, through a clinical case, the possibility of obtaining excellent predictability in implant-supported single crowns, through the use of multifunctional guides, inthe planning of a treatment from beginning to end. Case report:Patient A.M.F, 44 years old, female, came to the Prosthodontics clinic at the Department of Dentistry/UFRN complaining of dissatisfaction with her removable prosthesis and the harmony of her smile. Clinical and radiographic examination revealed the absence of element 12, with an interocclusal space of 5mm and a mid-distal distance of 7mm. The acrylic resin guide was made and the edentulous space was filled with a stock tooth. The center of theguide tooth was then drilled with a spherical straight-bit burr in the cingulum region and filled with gutta-percha stick. The patient was then referred for a cone beam computed tomography with the multifunctional guide in position. The images obtained allowed planning for implant installation, such as favorable inclination and positioning, as well as the absence of bone availability in the region. In addition, the guide was effective during other stages of the patient's treatment, such as the provisional phase.Conclusion:The guides assist in various phases of treatment and allow greater predictability of results in implant-supported single prosthetic rehabilitations, presenting themselves as a promising device for correct implant positioning (AU).

Introducción:En busca de estética y función masticatoria, la demanda de rehabilitaciones implantosoportadas es cada vez mayor. La guía multifuncional hasurgido para orientar la disponibilidad ósea y ayudar a planificar la instalación tridimensional de implantes, siguiendo los principios de la planificación inversa. Objetivo: Describir, a través de un caso clínico, la posibilidad de obtener una excelente predictibilidad en coronas unitarias implantosoportadas, mediante el uso de guías multifuncionales, en la planificación desde el início hasta el final del tratamiento. Informe de caso: Paciente A.M.F, 44 años, sexo femenino, compareció a la clínica de Prostodoncia del Departamento de Odontología/UFRN quejándose estar insatisfecha con su prótesis removible y con la armonía de su sonrisa. El examen clínico y radiográfico reveló la ausencia del elemento 12, con un espacio interoclusal de 5 mm y una distancia medio-distal de 7 mm. Se confeccionó una guía de resina acrílica y se rellenó el espacio edéntulo con un diente provisorio. A continuación, se perforó el centro del diente guía con una broca recta esférica en la región del cíngulo y se le rellenó con gutapercha en barra. Posteriormente, el paciente fue remitido a una tomografía computarizada cone beamcon la guía multifuncional en posición. Las imágenes obtenidas permitieron planificar la instalación del implante, como inclinación y posicionamiento favorables, así como la ausencia de disponibilidad ósea en la región. La guía también funcionó en otras fases del tratamiento del paciente, como en la fase provisional. Conclusión:Las guías ayudan en varias fases del tratamiento y permiten una mayor previsibilidadde los resultados en rehabilitaciones protésicas unitarias implantosoportadas, presentándose como un dispositivo prometedor para el correcto posicionamiento de los implantes (AU).

Reabilitação oral com próteses parciais removíveis após restabelecimento de dimensão vertical de oclusão e tratamento multidisciplinar: relato de caso / Oral rehabilitation with removable partial dentures after restoration of the vertical dimension of occlusion and multidisciplinary treatment: case report

As próteses parciais removíveis (PPRs) são uma alternativa de tratamento viável na prática clínica para reabilitar arcos parcialmente desdentados. Entretanto, o planejamento dessas próteses e preparo bucal prévio são frequentemente negligenciados. O presente artigo tem como objetivo relatar o caso clínico de uma reabilitação oral com PPRs superior e inferior após abordagem multidisciplinar, de modo a enfatizar as fases de um planejamento criterioso e de preparo prévio dos dentes pilares, visando o sucesso e a longevidade da reabilitação. Paciente do sexo masculino de 57 anos de idade compareceu à clínica da Faculdade de Odontologia de Bauru, Universidade de São Paulo, queixando-se da estética de seu sorriso e de algumas ausências dentárias. O indivíduo utilizava uma PPR provisória inferior insatisfatória e apresentava perda de dimensão vertical de oclusão (DVO). Após o exame clínico, radiográfico e estudo do caso em articulador semi-ajustável, realizou-se o planejamento com abordagens restauradoras, endodônticas, periodontais e protéticas. Após tratamento periodontal, foi realizada endodontia dos elementos 12, 15 e 47, confecção de núcleos e coroas nos dentes 12 e 15, restauração a nível gengival para apoio residual no dente 47, restaurações nos dentes 11, 13, 22, 24 e 44 e, por fim, a confecção das PPRs superior e inferior. A abordagem multidisciplinar utilizada neste caso clínico viabilizou o restabelecimento da DVO e possibilitou o sucesso da reabilitação protética(AU)

Removable partial dentures (RPDs) are a viable treatment alternative in clinical practice to rehabilitate partially edentulous arches. However, the planning of these dentures and prior oral preparation are often neglected. This article aims to report the clinical case of an oral rehabilitation with upper and lower RPDs after a multidisciplinary approach, to emphasize the phases of careful planning and prior preparation of the abutment teeth, aiming at the success and longevity of the rehabilitation. A 57-year-old male patient came to the clinic of the Bauru School of Dentistry, University of São Paulo, complaining about the esthetics of his smile and some missing teeth. The subject was using an unsatisfactory lower provisional prosthesis and had a loss of vertical dimension of occlusion (OVD). After the clinical and radiographic examination and the case study in a semi-adjustable articulator, planning was carried out with restorative, endodontic, periodontal and prosthetic approaches. After periodontal treatment, endodontics were performed on elements 12, 15 and 47, creation of cores and crowns on teeth 12 and 15, restoration at the gingival level for residual support on tooth 47, restorations on teeth 11, 13, 22, 24 and 44 and, finally, the making of the upper and lower PPRs. The multidisciplinary approach used in this clinical case enabled the restoration of the OVD and enabled the success of the oral rehabilitation(AU)

Prediction, analysis and application of learning curve of tooth preparation for all ceramic crowns of maxillary central incisors / 北京大学学报(医学版)

OBJECTIVE@#To predict the learning curve of tooth preparation for all ceramic crowns of maxillary central incisors on phantom head simulators for graduate students participating in standardized dental resident training based on the modified Wright learning curve model, then to analyze and applicate the learning curve.@*METHODS@#Twelve graduate students participating in standardized dental resident training were selected to prepare the resin maxillary central incisors on phantom head simulators for all ceramic crowns 4 times. The results of preparation were evaluated by 3 prosthetic experts with at least 10 years' experience focusing on the reduction, contour, taper, shoulder, finish line, margin placement, adjacent tooth injury, and preparation time for tooth preparation. The learning rate of tooth preparation was calculated by scores of tooth preparation of 4 times. The learning curve of tooth preparation was predicted based on the modified Wright learning curve model. According to the criteria of standardized training skill examinations for dental residents in Beijing, 80 was taken as the qualified standard score. The minimum training times for tooth preparation to satisfy the qualified standard score (80) was calculated, to analyze the characteristics of learning curve and evaluate the effectiveness of tooth preparation.@*RESULTS@#The scores of 4 tooth preparation were 64.03±7.80, 71.40±6.13, 74.33±5.96, and 75.98±4.52, respectively. The learning rate was (106±4)%, which showed the learning curve an upward trend. There were no significant differences between the qualified standard score and the predicted scores of tooth preparation from the 5th preparation to the 13th preparation (P > 0.05). The predicted score of the 14th preparation was higher than the qualified standard score (P < 0.05).@*CONCLUSION@#The trend of the learning curve of tooth preparation for all ceramic crowns of maxillary central incisors on phantom head simulators for graduate students participating in standardized dental resident training is upward, which predicts the minimum training times higher than the qualified standard score is 14 times.

Prosthetic maintenance assessment for implant fixed complete dentures and implant overdentures: a randomized clinical trial / Avaliação da manutenção protética para próteses totais fixas suportadas por implantes e Overdentures: um ensaio clínico randomizado

Objective: The rehabilitation choice for the edentulous patients usually lies between the fixed and removable prosthetic options. The treatment decisions are affected by many factors where complications and maintenance needs are both considered crucial factors, in addition to the cost effectiveness of the chosen treatment. Material and Methods: This study was applied on 44 edentulous patients, where 22 patient for each group were enrolled in the outpatient clinic of prosthodontics, Cairo University as per a set of eligibility criteria. Four inter-foraminal implants were installed for all eligible participants. Three months later, healing abutments were used for soft tissue preparation prior to the fabrication of the final prosthesis. A prosthetic treatment option was then randomly allocated to obtain two equal groups via computer generated randomization program; Group. A received telescopic implant overdentures, and Group. B received screw retained dentures. All Complications (Screw loosening or fracture, tooth or denture base fracture and mucositis) were reported after overdenture insertion along the follow up period (1, 6, 9 and 12 months respectively). Results: The frequency of the screw loosening for hybrid overdentures where (59.1%) compared to (27.3%) of telescopic prosthesis at 12 months follow up period (p=0.035), mucositis reporting at 6m interval had shown the highest frequency in both groups (Group A (54.5%), Group B (81.8%), (p=0.045), all other reported complications that lack statistical significance either within the same group or between both groups at different time intervals. Conclusion: Both treatment modalities; telescopic implant overdenture and hybrid fixed screw-retained are reliable for restoring the completely edentulous arches, the decision whether to make a fixed or removable implant denture shall be guided with the patient preference together with the dentist assessment in relation (AU)

Objetivo: A escolha da reabilitação para pacientes edêntulos geralmente recai entre próteses fixas e removíveis. As decisões de tratamento são afetadas por muitos fatores onde as complicações e as necessidades de manutenção são consideradas critérios cruciais, além do custo-efetividade do tratamento escolhido. Material e Métodos: Este estudo foi aplicado em 44 pacientes edêntulos, onde 22 pacientes para cada grupo foram matriculados no ambulatório de prótese dentária da Universidade do Cairo de acordo com um conjunto de critérios de elegibilidade. Quatro implantes interforaminais foram instalados para todos os participantes elegíveis. Três meses depois, pilares de cicatrização foram utilizados para preparação dos tecidos moles antes da fabricação da prótese final. Uma opção de tratamento protético foi então alocada aleatoriamente para obter dois grupos iguais por meio de andomização gerada através programa de computador. O Grupo A recebeu overdentures de implantes telescópicos e o Grupo B recebeu dentaduras fixas parafusadas sobre os implantes. Todas as complicações (afrouxamento ou fratura do parafuso, fratura da base do dente ou da prótese e mucosite) foram relatadas após a inserção da overdentures ao longo do período de acompanhamento (1, 6, 9 e 12 meses, respectivamente). Resultados: A frequência do afrouxamento do parafuso para Overdentures híbridas (59,1%) em comparação com (27,3%) da prótese telescópica no período de acompanhamento de 12 meses (p=0,035), o relato de mucosite no intervalo de 6 meses mostrou a maior frequência em ambos os grupos (Grupo A (54,5%), Grupo B (81,8%), p=0,045, todas as outras complicações relatadas foram sem significância estatística dentro do mesmo grupo ou entre os dois grupos em intervalos de tempo diferentes. Conclusão: Ambas as modalidades de tratamento; overdentures sobre implantes telescópicos e próteses híbridas fixas parafusadas são confiáveis para reabilitar as arcadas completamente edêntulas. A decisão de fazer uma prótese fixa ou removível sobre implantes deve ser guiada pela preferência do paciente juntamente com a avaliação do dentista em relação ao estado geral do paciente e sua saúde bucal. (AU)

Reabilitação oral utilizando prótese parcial removível associada a implantes osseointegrados: relato de caso / Oral rehabilitation using removable partial prosthesis associated with osseointegrated implants: case report

Introdução: As próteses parciais removíveis são alternativas amplamente utilizadas na reabilitação oral de pacientes parcialmente desdentados. Na atualidade os implantes dentais têm sido indicados para tratamento de pacientes edêntulos em associação com próteses parciais removíveis convencionais. Objetivo: Relatar um caso clínico utilizando uma prótese parcial removível convencional associada a implantes osseointegrados em paciente portador de Classe I de Kennedy. Relato de Caso: Paciente N.A.A.S., sexo feminino, 65 anos, procurou atendimento clínico no Instituto de Estudos da Saúde (IES) para reabilitação protética das arcadas dentais superior e inferior. A sua queixa principal era "dificuldade de mastigação". A paciente apresentava prótese total removível insatisfatória na maxila e não utilizava nenhum tipo de prótese dentária na mandíbula, que se apresentava parcialmente edêntula. O tratamento realizado foi a confecção de uma prótese total na arcada superior. Na arcada inferior foram inseridos dois implantes de hexágono externo nas regiões correspondentes às áreas dos dentes 34 e 44, após quatro meses a prótese parcial removível convencional foi confeccionada e incorporada aos implantes osseointegrados utilizando o sistema de retenção do tipo attachments Equator. Conclusão: Os resultados revelaram que a técnica de associação da prótese parcial removível convencional aos implantes osseointegrados demonstrou ser uma opção viável de tratamento com capacidade de devolver a função, a estética e manter a integridade dos dentes e tecidos periodontais(AU)

Introduction: Removable partial dentures are alternatives widely used in the oral rehabilitation of partially edentulous patients. Currently, dental implants have been indicated for the treatment of edentulous patients in association with conventional removable partial dentures. Objective: To report a clinical case using a conventional removable partial denture associated with osseointegrated implants in a patient with Kennedy Class I. Case Report: Patient N.A.A.S., female, 65 years old, sought clinical care at the Institute of Health Studies (HEI) for prosthetic rehabilitation of the upper and lower dental arches. His main complaint was "chewing difficulty". The patient had unsatisfactory removable total prosthesis in the maxilla and did not use any type of dental prosthesis in the mandible, which was partially edentulous. The treatment performed was the manufacture of a total prosthesis in the upper arch. In the lower arch, two external hexagon implants were inserted in the regions corresponding to the tooth areas 34 and 44, after four months the conventional removable partial denture was made and incorporated into the osseointegrated implants using the equator attachments retention system. Conclusion: The results revealed that the technique of associating conventional removable partial dentures with osseointegrated implants proved to be a viable treatment option with the ability to restore function, aesthetics and maintain the integrity of teeth and periodontal tissues(AU)

Independent innovation research, development and transformation of precise bionic repair technology for oral prosthesis / 北京大学学报(医学版)

According to the fourth national oral health epidemiological survey report (2018), billions of teeth are lost or missing in China, inducing chewing dysfunction, which is necessary to build physiological function using restorations. Digital technology improves the efficiency and accuracy of oral restoration, with the application of three-dimensional scans, computer-aided design (CAD), computer-aided manufacturing (CAM), bionic material design and so on. However, the basic research and product development of digital technology in China lack international competitiveness, with related products basically relying on imports, including denture 3D design software, 3D oral printers, and digitally processed materials. To overcome these difficulties, from 2001, Yuchun Sun's team, from Peking University School and Hospital of Stomatology, developed a series of studies in artificial intelligence design and precision bionics manufacturing of complex oral prostheses. The research included artificial intelligence design technology for complex oral prostheses, 3D printing systems for oral medicine, biomimetic laminated zirconia materials and innovative application of digital prosthetics in clinical practice. The research from 2001 to 2007 was completed under the guidance of Prof. Peijun Lv and Prof. Yong Wang. Under the support of the National Natural Science Foundation of China, the National Science and Technology Support Program, National High-Tech R & D Program (863 Program) and Beijing Training Project for the Leading Talents in S & T, Yuchun Sun's team published over 200 papers in the relevant field, authorized 49 national invention patents and 1 U.S. invention patent and issued 2 national standards. It also developed 8 kinds of core technology products in digital oral prostheses and 3 kinds of clinical diagnosis and treatment programs, which significantly improved the design efficiency of complex oral prostheses, the fabrication accuracy of metal prostheses and the bionic performance of ceramic materials. Compared with similar international technologies, the program doubled the efficiency of bionic design and manufacturing accuracy and reduced the difficulty of diagnosis and cost of treatment and application by 50%, with the key indicators of those products reaching the international leading level. This program not only helped to realize precision, intelligence and efficiency during prostheses but also provided functional and aesthetic matches for patients after prostheses. The program was rewarded with the First Technical Innovation Prize of the Beijing Science and Technology Awards (2020), Gold Medal of Medical Research Group in the First Medical Science and Technology Innovation Competition of National Health Commission of the People's Republic of China (2020) and Best Creative Award in the First Translational Medical Innovation Competition of Capital (2017). This paper is a review of the current situation of artificial intelligence design and precision bionics manufacturing of complex oral prosthesis.

Confección de prótesis de carga inmediata mediante barras articuladas: componentes, modo de uso y longitud de la barra en función de la localización / Fabrication of immediately loaded prostheses using articulated bars: components, method of use and bar length depending on the location

En la implantología actual, la confección de prótesis de carga inmediata se ha convertido en un procedi-miento de rutina. Contar con elementos pre-formados con un correcto ajuste al implante o transepitelial so-bre el que se trabaja, minimiza el tiempo de trabajo sin renunciar a la eficiencia. En el presente trabajo se muestran elementos preformados articulados para la realización de prótesis de carga inmediata y su forma de uso, así como un análisis biomecánico de las estructuras para conocer su repercusión en las distintas fuerzas recibidas durante la masticación. Resultados: Al aplicar la carga en la zona central de la barra (paralela a los implantes), la tensión máxima recibida en la zona correspondiente al extremo de la barra sufre variaciones importantes, desde 128 Mpa en la longitud de 13 mm hasta un máximo de 391 Mpa (megapascales) en la longitud de 5 mm, siendo la ten-sión máxima, media para todas las medidas, de 242 Mpa (+/-96,76). En el ensayo de las diferentes medi-das de la barra se observa también una tensión cre-ciente para longitudes de barra a partir de 7 mm, al aplicar la tensión en la zona media de la estructura, por lo que longitudes entre 5 y 7 mm pueden consi-derarse prácticamente con la misma distribución de tensiones hacia los extremos y en la zona de unión. En conclusión, las barras articuladas son un elemento de confección de prótesis provisionales de carga in-mediata de gran utilidad, que pueden confeccionarse de forma rápida y generan un comportamiento bio-mecánico predecible (AU)

In current implantology, the fabrication of immediately loaded prostheses has become a routine procedure. Being able to have pre-formed elements with a correct fit to the implant or transepithelial on which we are working minimizes working time without sacrificing efficiency. Material and methods: We show articulated preformed elements for immediate loading prostheses and how they are used, as well as a biomechanical analysis of the structures to determine their repercussion on the different forces received during mastication. Results: When the load is applied in the central area of the bar (parallel to the implants) the maximum stress received in the area corresponding to the end of the bar undergoes significant variations, from 128 Mpa in the 13 mm length to a maximum of 391 Mpa in the 5 mm length, the average maximum stress for all the measurements being 242 Mpa (+/-96.76). In the test of the different bar sizes we can also observe an increasing stress for bar lengths from 7 mm onwards when applying the stress in the middle zone of the structure, so that lengths between 5 and 7 mm can be considered to have practically the same stress distribution towards the ends and in the joint zone. Conclusions: Hinged bars are a very useful fabrication element for immediately loaded provisional prostheses, which can be fabricated quickly and generate a predictable biomechanical behavior (AU)

Initial establishment of digital reference standardized crown models of the primary teeth / 北京大学学报(医学版)

OBJECTIVE@#To explore the construction process of the digital reference crown models, and to initially establish the digital reference crown models of the primary teeth to lay the foundation for the establishment of the standardized crown models and the future related applications of computer-aided design/computer-aided manufacture (CAD/CAM) technology to pediatric dentistry.@*METHODS@#This study randomly selected children who were caries free, aged from 4 to 5 years in several kindergartens of Haidian District of Beijing.Plaster dental models were made for the children after taking complete impressions.The digital dental models were reconstructed by using the three-dimensional (3D) dental model scanner.And then, Geomagic Studio, a 3D reverse engineering software, was employed to extract the single dental crown data, the mesiodistal and buccolingual diameters and the height of the crowns were measured.The object was reduced or enlarged by a numerical factor, and then the size of each dental crown was standardized.A total of 3-5 points features on the crown were created, and all the objects were aligned through the functions of feature-based alignment.Finally, through average-based object creation and smoothing, the digital models of reference crowns of the primary teeth were established.@*RESULTS@#A total of 40 plaster dental models from 16 boys and 26 girls were selected out for our further study.The digital dental models were reconstructed, and the mesiodistal and buccolingual diameters and the height of the crowns were measured by using reverse engineering technology.Comparing the results of using mesiodistal diameter, buccolingual diameter and height as the standards, we chose the mesiodistal diameters of crowns to do the standardization, and successfully established the digital reference models of 20 primary teeth crowns with detailed surface characteristics.@*CONCLUSION@#In this study, the digital reference crown models of the primary teeth were established by reverse engineering technology, providing reference value for the standardized crown models and application for clinical practice, scientific research and teaching.Furthermore, this study also contributes to the extensive application of CAD/CAM technology in pediatric dentistry and the development of CAD/CAM dental systems with independent intellectual property rights.

Effect of prosthetic design and restorative material on the stress distribution of implant-supported 3-unit fixed partial dentures: 3D-FEA / Efeito do desenho protético e do material restaurador na distribuição de tensão de próteses parciais fixas de 3 elementos suportada por implante: FEA 3D

Objective: Evaluate the effect of Implant prosthetic designs and restorative material on the stress concentration of 3-unit implant-supported restoration with two restorative materials. Material and Methods: Six different screw-retained prostheses models were virtually designed and divided according to design: fixed bridge (FB), cantilever bridge (CB), and separate crowns (SC). Then, each model was also divided into two subgroups according to the material: Ultra-translucent multi-layered zirconia (Kuraray Noritake Dental Inc., Japan); or a combination of PEEK (Polyetheretherketone) framework (BioHPP, Bredent, GmbH & Co., KG, Germany) and zirconia (ZR) crowns (ultra-translucent multi-layered zirconia, Kuraray Noritake Dental Inc., Japan). A vertical load of 100 N was applied statically perpendicular to the central fossa of each crown. The von-Mises stress was computed using Solidworks software (SolidWorks Corp, Massachusetts, USA), based on the physical parameters of the materials. Results: FB showed the lowest von Mises stress values out of all 3 design models. Moreover, the combination of PEEK and zirconia showed strain values smaller than full zirconia. The highest von Mises stress value was recorded in CB with the zirconia subgroup at (1098 MPa) while the lowest von Mises stress value was recorded in FB with combined PEEK and zirconia subgroup at (190 MPa). Conclusion: For three-unit implant supported restorations, the use of PEEK framework and zirconia crowns was found to be more favorable biomechanically regarding the prosthetic components, implant and bone stresses. (AU)

Objetivo: Avaliar o efeito do desenho da prótese sobre implantes e do material restaurador na concentração de tensão de próteses fixas de 3 elementos implantossuportada, com dois materiais restauradores. Material e Métodos: Seis diferentes modelos de próteses aparafusadas foram virtualmente projetados e divididos de acordo com o desenho: ponte fixa (PF), ponte cantilever (PC) e coroas individuais (CI). Em seguida, cada modelo também foi dividido em dois subgrupos de acordo com o material: Zircônia multicamada ultra translúcida (Kuraray Noritake Dental Inc., Japão); ou associada a uma estrutura de PEEK (Polyetheretherketone) (BioHPP, Bredent, GmbH & Co., KG, Alemanha) e coroas de zircônia (CZ) (zircônia multicamada ultra translúcida, Kuraray Noritake Dental Inc., Japão). Uma carga vertical estática de 100 N foi aplicada perpendicular à fossa central de cada coroa. A tensão de von-Mises foi calculada usando o software Solidworks (SolidWorks Corp, Massachusetts, EUA), com base nos parâmetros físicos dos materiais. Resultados:PF apresentou os menores valores de tensão de von Mises de todos os 3 modelos propostos. Além disso, a combinação de PEEK e zircônia apresentou valores de deformação menores do que a zircônia pura. O maior valor de tensão de von Mises foi registrado em PC com o subgrupo de zircônia em (1098 MPa), enquanto o menor valor de tensão de von Mises foi registrado em PF com PEEK combinado e subgrupo de zircônia em (190 MPa). Conclusão: Para ponte fixa de 3 elementos implantossuportadas, o uso de estrutura PEEK e coroas de zircônia mostrou-se mais favorável biomecanicamente em relação aos componentes protéticos, implante e tensão sobre o osso. (AU)

Consensos referidos a conceptos rehabilitadores en la enseñanza de la odontología. Parte I: conceptos generales y diseño de la prótesis parcial removible / Consensus referring rehabilitative concepts in the teaching of dentistry. Part I: general concepts and design of removable partial prosthesis

En este artículo se desarrolla el consenso alcanzado entre profesores, referido a los conceptos generales, componentes y la secuencia del diseño de la prótesis parcial removible, durante la formación del odontó-logo en el ámbito de la Facultad de Odontología de la Universidad de Buenos Aires (AU)

This article develops the consensus between professors on the general concepts, components, and the sequence of the design of the partial removable prosthesis during the training of the dentist in the field of the Faculty of Dentistry of the University of Buenos Aires (AU)

Reabilitação estética dos dentes anteriores superiores associando coroa sobre implante e facetas cerâmicas: relato de caso / Esthetic rehabilitation of maxillary anterior teeth associating crown implant-supported and ceramic veneers: case report

Este relato descreve o caso de uma paciente jovem que necessitou de reabilitação na região maxilar anterior devido a insatisfações estéticas. O artigo objetivou relatar a sequência clínica da reabilitação de um implante pré-existente na região do dente 21 com UCLA de zircônia personalizável e coroa de dissilicato de lítio associada a instalação de facetas de dissilicato de lítio dos dentes 15 ao 25 para harmonização do sorriso. Previamente ao tratamento reabilitador, foi realizado o planejamento do caso que incluiu a necessidade de gengivectomia e condicionamento do perfil de emergência na região peri-implantar. Após a cicatrização, foram confeccionados preparo minimamente invasivos de acordo com as informações do mock-up. UCLA personalizável de zircônia foi selecionada como componente protético, visando a estética do caso. Para a moldagem, utilizou-se transfer de moldeira aberta para cópia do perfil de emergência e posicionamento do implante na região do 21 e moldagem simultânea com silicone de adição. Após a prova, a cimentação das facetas de dissilicato de lítio foi realizada com cimento adesivo fotopolimerizável. Os resultados estéticos e funcionais foram satisfatórios. No presente caso clínico, conclui-se a importância da abordagem multidisciplinar para alcançar resultados satisfatórios. Ademais, a associação das facetas e a coroa de dissilicato de lítio implantossuportada com UCLA de zircônia personalizável proporcionou os resultados estéticos e funcionais da paciente(AU)

This report describes the case of a Young patient who needed rehabilitation in the anterior maxillary region due to esthetic involvement. The article aimed to report the clinical sequence of the rehabilitation of a pre-existing implant in the region of tooth 21 with UCLA of zirconia customizable and crown of lithium disilicate associated with the installation of veneers of lithium disilicate of teeth 15 to 25 for harmonizing the smile. Prior to the rehabilitation treatment, case planning was carried out, which included the need for gingivectomy and conditioning of the emergency profile in the peri-implant region. After healing, preparations minimally invasive were made according to the information of mock-up. UCLA of zirconia customizable was selected as a prosthetic component, aiming at the aesthetics of the case. For impression, open tray transfer was used to copy the emergency profile and position the implant in the region of 21 and simultaneous impression with addition silicone. After the test of veneers, the cementation of veneers of lithium disilicate was performed with adhesive cement light-curing. The esthetic and functional results were satisfactory. In the present clinical case, the importance of a multidisciplinary approach to achieve satisfactory results is concluded. In addition, the combination of veneers and crow implanted of lithium disilicate with customizable zirconia UCLA provided the patient's esthetic and functional results(AU)

Planejamento reverso em implantodontia: revisão de literatura / Reverse planning in implantology: literature review

A Odontologia atual apresenta relevantes mudanças no processo de reabilitação oral. Com isso, a instalação de implantes osseointegrados, constituem uma importante ferramenta neste âmbito, pois permitem a devolução da função mastigatória, permitindo também que os pacientes tenham a estética recuperada. O presente trabalho tem como objetivo realizar uma revisão de literatura, sobre a importância de um planejamento prévio, chamado também de planejamento reverso, o mesmo aponta um maior sucesso no processo reabilitador, apresentando-se como uma técnica que busca facilitar e estudar a correta reabilitação do paciente, proporcionando uma melhor previsibilidade para o tratamento, a partir do momento em que se planeja a reabilitação oral protética antes mesmo de se pensar no processo cirúrgico de implantes osseointegrados. Conclui-se com esse trabalho que o sucesso do tratamento com implantes depende diretamente de um prévio plano de tratamento, independentemente da extensão da área edêntula, quando é realizado um planejamento reverso diminuiu-se a taxa de intercorrências, além de aumentar a taxa de sucesso no processo de reabilitação(AU)

Current Dentistry presents relevant changes in the oral rehabilitation process. As a result, the installation of osseointegrated implants is na important tool in this context, as it allows the return of lost teeth, also allowing patients to have their function and aesthetics recovered. For greater success of the rehabilitation process, reverse planning presents itself as a technique that seeks to facilitate the correct rehabilitation of the patient, allowing better predictability for the treatment from the moment that the prosthetic oral rehabilitation is planned before even thinking about the surgical process of osseointegrated implants. The success of treatment with implants depends directly on a properly planned treatment plan, regardless of the extent of the edentulous area. This paper aims to conduct a literature review on the importance of reverse planning in implantology(AU)

Prosthetic dental management of a patient with anhidrotic ectodermal dysplasia: a case report / Manejo protésico dental de un paciente con displasia ectodérmica anhidrótica: reporte de caso

Introduction: Ectodermal dysplasia (ED) comprises a broad group of genetic disorders characterized by alterations of the structures derived from the ectoderm, including those of the stomatognathic system. Case Report: The present article aims to report the prosthetic management of a patient with anhidrotic ectodermal dysplasia. A male patient diagnosed with ED who attended the dental consultation displaying oligodontia; underdeveloped alveolar ridges were observed. Results: The established treatment consisted of the adaptation of implant-supported fixed full-arch prosthesis designed through CAD-CAM technology for the lower jaw and of a removable partial prosthesis with muco-dental support for the upper jaw. The dental approach of patients with ED is based on a correct analysis of the facial characteristics and stomatological conditions of each subject. Conclusion: A multidisciplinary approach is mandatory due to the biological and functional complexity in biomechanical terms of these individuals.

Introducción: La displasia ectodérmica (DE) comprende un amplio grupo de trastornos genéticos caracterizados por alteraciones de las estructuras derivadas del ectodermo, incluidas las del sistema estomatognático. Reporte de Caso: El presente artículo tiene como objetivo informar del manejo protésico de un paciente con displasia ectodérmica anhidrótica. Paciente varón diagnosticado de DE acudió a consulta odontológica por oligodoncia; Se observaron crestas alveolares subdesarrolladas. Resultados: El tratamiento establecido consistió en la adaptación de una prótesis de arcada completa fija implantosoportada diseñada mediante tecnología CAD-CAM para el maxilar inferior y de una prótesis parcial removible con soporte muco-dental para el maxilar superior. El abordaje odontológico de los pacientes con DE se basa en un correcto análisis de las características faciales y condiciones estomatológicas de cada sujeto. Conclusión: Un enfoque multidisciplinario es obligatorio debido a la complejidad biológica y funcional en términos biomecánicos de estos individuos.

Tasa de supervivencia de prótesis fija unitaria de cerámica feldespática y feldespática reforzada / Survival rate of feldspathic and reinforced feldspathic ceramic single-unit fixed prostheses

Introducción: Gracias a su eficiencia y al uso exclusivo de cerámicas libres de metal, en rehabilitación oral se ha logrado alcanzar los estándares estéticos y mecánicos, manteniendo o, incluso, superando, la calidad de los tratamientos en comparación con las restauraciones metal cerámicas tradicionales. Actualmente los mecanismos de confeccion de cerámica libre están evolucionando cada vez mas hacia las tecnologías maquinadas CAD-CAM y disminuyendo su producción mediante la técnica de Inyeccion PRESS. Objetivo: Comparar la tasa de supervivencia de prótesis fija unitaria realizadas con cerámicas feldespáticas convencionales y reforzadas con disilicato de litio, confeccionadas con sistema CAD/CAM de CEREC® chair-side, en comparación con el método de inyección de laboratorio PRESS convencional de prensión. Métodos: Revisión sistemática realizada a través de búsqueda de evidencia científica en PubMed, PubMed Clinical Queries, Epistemónikos, Tripdatabase, Cochrane Library, recursos electrónicos de la Universidad de los Andes y bibliografía retrógrada, de artículos publicados hasta el año 2019. Se incluyeron todos aquellos estudios referentes a prótesis fija unitaria de cerámicas feldespática convencional y feldespática reforzada con disilicato de litio, confeccionadas mediante CAD/CAM y/o método convencional. Resultados: Un total de 28 artículos cumplieron los criterios de inclusión: 21 estudios observacionales de cohorte, 4 ensayos clínicos aleatorizados y 3 no aleatorizados. A corto y mediano plazo, CAD/CAM de CEREC® registró tasas de supervivencia de 98 por ciento y 91,9 por ciento, respectivamente. El sistema convencional registró tasas de supervivencia de 97,5 por ciento a corto plazo y 93 por ciento a mediano. Conclusiones: A corto plazo se describe en la literatura que CAD/CAM de CEREC® tuvo una tasa de supervivencia ligeramente superior al sistema convencional. Por otro lado, a mediano plazo CAD/CAM de CEREC® presentó una leve disminución respecto al sistema convencional. Aún no hay estudios disponibles para determinar la supervivencia clínica de los tratamientos a largo plazo(AU)

Introduction: Thanks to its efficiency and the exclusive use of metal-free ceramics, in oral rehabilitation it has been possible to achieve aesthetic and mechanical standards, maintaining or even exceeding the quality of the treatments compared to traditional metal-ceramic restorations. Currently, free ceramic manufacturing mechanisms are increasingly evolving towards CAD-CAM machined technologies and decreasing their conventional production through the PRESS Injection technique. Objective: Compare the survival rate of single-unit fixed prostheses made with conventional feldspathic ceramics and reinforced with lithium disilicate by the CEREC® CAD/CAM chairside system, with the conventional PRESS laboratory injection method. Methods: A systematic review was conducted of scientific evidence included in papers published until the year 2019 in PubMed, PubMed Clinical Queries, Epistemonikos, Tripdatabase, Cochrane Library, electronic resources of Los Andes Peruvian University, and retrograde bibliography. The papers selected dealt with conventional and lithium-disilicate reinforced feldspathic ceramic single-unit prostheses made by CAD/CAM and/or the conventional method. Results: A total 28 papers met the inclusion criteria. Of these, 21 were observational cohort studies, four were randomized clinical assays and three were non-randomized assays. Short- and mid-term, CEREC® CAD/CAM achieved survival rates of 98 percent and 91.9 percent, respectively. The conventional system achieved survival rates of 97.5 percent short-term and 93 percent mid-term. Conclusions: As described in the literature, CEREC® CAD/CAM had a slightly higher survival rate than the conventional system in the short term. In the medium term, however, CEREC® CAD/CAM displayed a slight reduction in comparison with the conventional system. No studies are available to determine the clinical survival of the treatments in the long term(AU)

Reabilitação prótetica convencional após remoção cirúrgica de hiperplasia fibrosa: relato de caso / Conventional prosthetic rehabilitation after surgical removal of fibrous hyperplasia: case report

O uso de próteses mal adaptadas pode ocasionar o surgimento de processos proliferativos não neoplásicos. A hiperplasia fibrosa inflamatória (HFI) é uma lesão benigna, proveniente de reação hiperplásica do tecido conjuntivo fibroso em resposta às injúrias crônicas de baixa intensidade. O objetivo do presente trabalho é relatar um caso clínico sobre remoção cirúrgica de HFI, seguida de reabilitação oral com próteses removíveis. Paciente de 75 anos do sexo masculino relatou que gostaria de fazer a troca da sua prótese, pois a mesma estava fraturada. Ao exame clínico intra-oral constatou-se que suas próteses possuíam higienização precária, e, a superior, possuía uma borda cortante que causou uma lesão hiperplásica na região de fundo de vestíbulo anterior. Quanto ao aspecto clínico, apresentava-se com consistência fibrosa e firme à palpação, de coloração semelhante a mucosa e assintomática. O plano de tratamento proposto foi reembasamento da prótese antiga com resina Soft Confort (Dencril, Brasil) eliminando as áreas que traumatizavam a mucosa, cirurgia pré-protética para a remoção da HFI, exame histopatológico e a confecção de novas próteses, sendo a superior prótese total convencional e a inferior prótese parcial removível. Observa-se a importância no cuidado do planejamento reabilitador protético dos pacientes, pois, como foi descrito neste caso, em algumas situações pode haver necessidade de lançarmos mão de diversas modalidades de tratamento prévias à reabilitação(AU)

The use of poorly adapted prostheses can lead to the emergence of non-neoplastic proliferative processes. Inflammatory fibrous hyperplasia (HFI) is a benign lesion, resulting from a hyperplastic reaction of fibrous connective tissue in response to low-intensity chronic injuries. The aim of the present study is to report a clinical case about surgical removal of HFI, followed by oral rehabilitation with removable prostheses. A 75-year-old male patient reported that he would like to change his prosthesis, because it was fractured. On intra-oral clinical examination, it was found that his prostheses had poor hygiene, and the upper one had a cutting edge that caused a hyperplastic lesion in the deep region of the anterior vestibule. As for the clinical aspect, it was fibrous and firm on palpation, mucosa-like and asymptomatic. The proposed treatment plan was to repurpose the old prosthesis with Soft Confort resin (Dencril, Brazil), eliminating the areas that traumatized the mucosa, pre-prosthetic surgery for the removal of HFI, histopathological examination and the making of new prostheses, the upper prosthesis being conventional total and the lower partial removable prosthesis. It is observed the importance in the care of the prosthetic rehabilitation planning of the patients, because, as it was described in this case, in some situations it may be necessary to resort to different treatment modalities prior to the rehabilitation(AU)

Different treatment modalities using dental implants in the posterior maxilla: a finite element analysis

Abstract The objective of this study was to compare the biomechanical behavior of peri-implant bone tissue and prosthetic components in two modalities of treatment for posterior region of the maxilla, using short implants or standard-length implants associated with bone graft in the maxillary sinus. Four 3D models of a crown supported by an implant fixed in the posterior maxilla were constructed. The type of implant: short implant (S) or standard-length implant with the presence of sinus graft (L) and type of crown retention: cemented (C) or screwed (S) were the study factors. The models were divided into SC- cemented crown on a short implant; SS- screwed crown on the short implant; LC- cemented crown on a standard-length implant after bone graft in the maxillary sinus and LS- crown screwed on a standard-length implant after bone graft in the maxillary sinus. An axial occlusal loading of 300 N was applied, divided into five points (60N each) corresponding to occlusal contact. The following analysis criteria were observed: Shear Stress, Maximum and Minimum Main Stress for bone tissue and von Mises Stress for the implant and prosthetic components. The use of standard-length implants reduced the shear stress in the cortical bone by 35.75% and the medullary bone by 51% when compared to short implants. The length of the implant did not affect the stress concentration in the crown, and the cement layer acted by reducing the stresses in the ceramic veneer and framework by 42%. Standard-implants associated with cemented crowns showed better biomechanical behavior.

Resumo O objetivo do estudo foi avaliar o comportamento biomecânico do tecido ósseo peri-implantar e dos componentes protéticos em duas modalidades de tratamento para região posterior da maxila, utilizando implantes curtos ou implantes de comprimento padrão associados a enxerto ósseo em seio maxilar. Foram construídos quatro modelos 3D de uma coroa suportada por um implante osseointegrado na região posterior da maxila. O tipo de implante: implante curto (S) ou implante de comprimento padrão com presença de enxerto sinusal (L) e tipo de retenção da restauração: cimentada (C) ou parafusada (S) foram os fatores de estudo. Foi aplicada uma força oclusal de 300N, dividida em cinco pontos (60 N cada) correspondentes ao contato oclusal de um primeiro molar superior. Foram observados os seguintes critérios de análise: tensão de cisalhamento, tensão principal máxima e mínima para o tecido ósseo e tensão de Von Mises para o implante e componentes protéticos. O uso de implantes de comprimento padrão reduziu a tensão de cisalhamento no osso cortical em 35,75% e no osso medular em 51% quando comparado aos implantes curtos. O comprimento do implante não afetou a concentração de tensão na restauração. A camada de cimento atuou reduzindo as tensões na cerâmica de cobertura e infraestrutura de cerâmica em 42%. Os implantes de tamanho padrão associados às coroas cimentadas apresentaram o melhor comportamento biomecânico.

Tilted implantation technique for edentulous patients / 华西口腔医学杂志

The tilted implantation technique is characterized by placing the implant at an angle of more than 15° and less than 45° from the horizontal plane. This technique can avoid damaging the maxillary sinus, inferior alveolar nerve, nasal base, and other anatomical structures when the height of the upper and lower jaw available bone is insufficient, to maximize the use of available bone and avoid a large range of bone increment. The tilted implantation technique can reduce the trauma of the surgery, increase the possibility of immediate restoration and shorten the treatment cycle, which has been widely used clinically. In this review, the scope of application, design elements, design scheme and complications of the tilted implantation technique for edentulous patients will be described.

Clinical observation of the curative effect after 5-year follow-up of single tooth implant-supported restorations in the posterior region / 北京大学学报(医学版)

OBJECTIVE@#To analyze the clinical curative effect after 5-year follow-up of single tooth implant-supported restorations in the posterior region.@*METHODS@#In the study, patients with single tooth implant-supported restorations in the posterior region after loading 5-year in the Second Clinical Division of Peking University School and Hospital of Stomatology from October 2005 to May 2010 was enrolled. The implant survival rate, prosthetic conditions (including the structural integrity or loosening of the prosthesis, the retention of the materials used to fill access holes of screw-retained implant crowns, loosening or fractures of the implant abutment or screw) and marginal bone lever level around implants were determined by clinical and radiographic examination.@*RESULTS@#The study was composed of 215 patients, the mean age was 48.6 years (range: 27 to 71), and 321 soft tissue implants were inserted. There were 9 implants loose and lost during the visit, the cumulative success rate was 97.2%. In the 312 remaining implants, 120 implants were placed in the upper jaws (38.5%) and 192 in the lower jaws (61.5%). Three different diameters as 3.3 mm (5 implants), 4.1 mm (115 implants) and 4.8 mm (192 implants) and three different lengths as 8 mm (21 implants), 10 mm (206 implants) and 12 mm (85 implants) were used, respectively. 277 (88.8%) cement-retained and 35 (11.2%) screw-retained implant-supported single crowns were made. The marginal bone loss (MBL) around dental implants after loading 5 years in the mesial and distal sides were (0.73±0.25) mm and (0.78±0.26) mm, respectively. There was no significant difference among MBL and bone quality, implant type, angle of abutment, prosthodontic type, crown-to-implant ratio, gender, and age of the patients (P > 0.05). The major mechanical complications after restoration involved loosening (8.6%) and fracture (2.9%) of the crown retainer screw, loss of resin covering the screw (11.4%), and the most frequent mechanical complications were loss of crown retention (14.1%) and fracture of porcelain (13.8%). The incidence of loss of crown retention was correlated with insufficient clinical crown height or using angle abutment (P < 0.05).@*CONCLUSION@#After loading 5 years, the bone level around the soft-tissue-implant placed in posterior region was stable. To minimize the frequency of mechanical complications after restoration, protocols must be established from diagnosis to the completion of treatment and follow up of implant-supported prostheses, especially in terms of adequate technical steps and careful radiographic evaluation of the components.