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)

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)

Screwed and cement implant prosthesis: current clinical considerations / Prótese sobre implante cimentada e parafusada: considerações clínicas atuais

ABSTRACT Introduction: There is no consensus as to which cemented or screwed retention system is best to avoid bone loss around the implant from a fixed implant-supported restoration. Objective: To evaluate the prosthesis retention systems on screw and cemented implants, regarding: bone loss, survival and failure rate, biological complications and microbiological analysis. Methods: A search was made for scientific articles that contemplated the subject through the databases Pubmed and SciELO, without period restriction. The titles, abstracts and then access to the full text has been verified. Results: It was found that excess cement may play an important role in the development of peri-implant disease. Technical failures are most seen in prosthesis retained by screws, and biological complications in cemented crowns. The success rate for both restraint systems is high, and retention-independent implant prosthesis treatment provides predictability. Conclusion: The appropriate retention system for the patient depends on several factors, including indication, advantages and disadvantages, retention provided, aesthetics and clinical performance.

RESUMO Introdução: Não há consenso sobre qual sistema de retenção, cimentado ou parafusado, é o melhor para evitar perda óssea ao redor do implante de uma restauração fixa implanto-suportada. Objetivo: Avaliar os sistemas de retenção de próteses sobre implantes parafusadas e cimentadas, quanto aos fatores: perda óssea, taxa de sobrevivência e de falhas, complicações biológicas e análises microbiológicas. Métodos: Foi realizada uma busca por artigos científicos que contemplassem o tema através das bases de dados Pubmed e SciELO, sem restrição de período. Os títulos, resumos e em seguida o acesso ao texto completo foi verificado. Resultados: Foi observado que o excesso de cimento pode desempenhar um papel importante no desenvolvimento da doença peri-implantar. Falhas técnicas são mais observadas em próteses retidas por parafusos e complicações biológicas em coroas cimentadas. A taxa de sucesso para os dois sistemas de retenção é alta e o tratamento com próteses sobre implantes independente da retenção oferece previsibilidade ao caso. Conclusão: O sistema de retenção apropriado para o paciente depende de diversos fatores, incluindo a indicação, vantagens e desvantagens, retenção fornecida, estética e desempenho clínico.

Resultados evaluativos en la asignatura prótesis removible en relación con los componentes académico, investigativo y laboral. Universidad de Guayaquil, 2017-2018 / Test results in the subject removable prosthesis in relation to the labor, research and academic components. University of Guayaquil, 2017-2018

RESUMEN Fundamento: En la carrera de Odontología de la Universidad de Guayaquil, la asignatura prótesis removible carece de un sistema estructurado para el contenido, que garantice la articulación de los componentes académico investigativo y laboral. Ello puede revertirse a mediano y largo plazo en deficiencias en el desempeño laboral de los futuros profesionales. Objetivo: describir los resultados evaluativos en la asignatura prótesis removible en relación con los componentes académico, investigativo y laboral. Métodos: se realizó un estudio observacional, correlacional, con diseño longitudinal de panel, para realizar un análisis en la asignatura prótesis removible, de la carrera de Odontología, en la Universidad de Guayaquil, Ecuador, durante el curso académico 2017-2018. Las variables fueron los resultados obtenidos en las evaluaciones por 57 estudiantes; y las valoraciones acerca los tres componentes articulados: académico, investigativo y laboral. Se emplearon estadísticos descriptivos de tendencia central y de dispersión, así como la prueba alternativa no paramétrica de los rangos con signo de Wilcoxon. Resultados: se observaron diferencias significativas en el promedio de las calificaciones en ambos trabajos investigativos para cada uno de los grupos. Los tres componentes mostraron un comportamiento similar, aunque quedó evidenciada una acentuada disminución del componente laboral. Conclusión: las calificaciones obtenidas revelan mejores resultados en el conocimiento teórico y en relación a habilidades para la actividad investigativa, no así para las actividades prácticas vinculadas al diseño de las prótesis. La integración de los tres componentes del proceso enseñanza-aprendizaje se ve afectada, al no estar debidamente potenciado el componente laboral.

ABSTRACT Foundation: in Odontology studies at the University of Guayaquil, the subject removable Prosthesis lacks a structured system that guarantees the articulation of the labor, research and academic components. That could be reverted at a medium and long terms in deficiencies at working performance in future professionals. Objective: to describe the tests results in the subject removable prosthesis in regards to abor, research and academic components. Methods: a correlational, observation study was developed with panel design, to develop the analysis of the subject removable prosthesis, of the Odontology studies at the University of Guayaquil, Ecuador during the academic year 2017-2018. The variables were the results obtained in the test of 57 students, valuations about the three components articulated: academic, research and labor, so as the alternative non parametric ranking test with Wilcoxon sign. Results: significant differences were observed in the average marks in both research works for each of the groups. The three components had a similar behavior, though there was evidence of a decrease in the labor component. Conclusion: the marks obtained revealed better results in theoretical knowledge related to research abilities, not in the same way in at the job practice linked to prosthesis design. The integration of the three components of the teaching learning process is affected since the labor component isn not properly developed.

ODEF no planejamento reverso de protocolo cerâmico ­ relato de caso / ODEF in the reverse planning of ceramic protocol ­ case report

O sucesso da reabilitação de pacientes edêntulos requer uma adaptação funcional e psicológica. As preocupações dos pacientes estão relacionadas ao conforto, à função e à estética. A prótese total sobre implantes é uma alternativa para pacientes totalmente desdentados com rebordo ósseo, que não proporciona retenção e nem estabilidade para uma prótese total convencional. Próteses sobre implantes esteticamente favoráveis estão diretamente relacionadas com a condição dos tecidos moles e duros que as envolvem. A preservação dos tecidos mucogengivais ao redor de implantes dentários instalados na maxila anterior propicia um sorriso harmonioso, com uma estética bastante agradável. O tratamento de reparação dentária deve ter início com a construção de próteses diagnósticas, onde o profissional pode prever o resultado final. Este artigo tem como objetivo mostrar a importância da gengiva artificial de porcelana em pacientes que tiveram reabsorção óssea, perda da DVO e perda de tecido gengival, utilizando o ODEF (Oral Design para Estética e Função Oclusal) no diagnóstico estético e oclusal como planejamento reverso.

The successful rehabilitation of edentulous patients requires a functional and psychological adaptation. Patient concerns are related to comfort, function and aesthetics. Total prosthesis on implants is an alternative for fully edentulous patients with a bone ridge that provides no retention and no stability for a conventional total prosthesis. Prostheses on aesthetically favorable implants are directly related to the condition of soft and hard tissues that surround them. The preservation of the mucogingival tissues around dental implants installed in the anterior maxilla provides a harmonious smile, with a pleasant aesthetic. The dental repair treatment should begin with diagnostic prostheses manufacturing, with which the professional can predict the final result. This article aims to show the importance of porcelain artificial gingiva in patients who have had bone resorption, loss of VDO and loss of gingival tissue, using ODEF (Oral Design for Aesthetics and Occlusal Function) in aesthetic and occlusal diagnosis as a reverse planning.

Removable partial denture with attachment as a treatment option in patients with cleft lip and palate / Prótese parcial removível com encaixe como opção de tratamento em paciente com fissura labiopalatina

ABSTRACT The rehabilitation treatment of patients with cleft lip and palate is lengthy and is carried out by various professionals from different areas of healthcare.To this end, planning and specialist knowledge are critical to the success of the treatment, in this way envisioning the aesthetic and functional rehabilitation of the individual in order to integrate them into society. This study consists of a literature review along with the report of a clinical case, demonstrating the treatment performed with the use of a removable partial denture using the abutment teeth treated with milled metal-ceramic crowns and the use of attachments, with a view to promoting the retention and stability of the prosthetic device. With the use of this system as a whole, aimed at improving the facial proportions due to the restoration of vertical dimension of occlusion and adequate lip support, features that are often not present in individuals with cleft lip and palate. In this work, we are seeking to underline the importance of scientific and technical knowledge, combined with a well-executed planning, in order to achieve successful treatment that restores function and aesthetics to the patient, thereby enabling their reintegration into society.

RESUMO O tratamento reabilitador de um paciente com fissura labiopalatina envolve um longo período e efetuado por diversos profissionais de diferentes áreas da saúde. Para tal, o planejamento e o conhecimento específico são de suma importância para o sucesso do tratamento, vislumbrando, dessa forma, a reabilitação estética e funcional do indivíduo de forma a integrá-lo na sociedade. O presente trabalho consiste em relato de um caso clínico, demonstrando o tratamento efetuado com a utilização de prótese parcial removível utilizando os dentes pilares tratados com coroas metalo-cerâmicas fresadas e a utilização de encaixes, com intuito de favorecer a retenção e estabilidade do aparelho protético. Com o uso de todo esse sistema objetivando a melhoria nas proporções faciais devido à devolução da dimensão vertical de oclusão e suporte labial adequado, características que muitas vezes não estão presentes nos indivíduos com fissuras labiopalatinas. Este trabalho tem o intuito de ressaltar a importância do conhecimento científico e técnico, somados a planejamento bem realizado a fim de se conseguir o sucesso do tratamento, devolvendo função e estética do paciente, reintegrando-o a sociedade.

Como utilizar o conceito da Zona Neutra para otimizar a Prótese / Using the Neutral Zone concept to improve the lower complete

Este artigo descreve os passos para a utilização da filosofia da Técnica da Zona Neutra. Através dessa filosofia, procura-se localizar uma área, em boca, onde as forças geradas pela língua são neutralizadas pelas forças geradas pelos lábios e bochechas, estabilizando assim a prótese.

This article describes step-by-step the application of the Neutral Zone technique philosophy. It is based upon the concept that for each individual patient, there is within the denture space a specific area where the function of the musculature will not unseat the denture and where forces generated by the tongue are neutralized by the forces generated by the lips and cheeks.

Restabelecimento da dimensão vertical de oclusão utilizando um JIG estético / Reestablishment of occlusal vertical dimension using an esthetic JIG

A dimensão vertical de oclusão (DVO) pode estar diminuída quando o relacionamento oclusal entre os dentes posteriores entra em colapso devido a ausência dentária, migrações ou desgastes severos. O presente relato de caso teve como objetivo apresentar uma técnica para restabelecer a DVO, denominada de JIG estético. Nesta técnica, um dente de estoque foi adaptado sobre um dos incisivos centrais superiores para determinar a linha média, volume dos incisivos, altura incisal e o aumento da DVO. Auxiliado por um planejamento digital do sorriso e do JIG estético, realizou-se um enceramento de diagnóstico e posterior mock-up. A utilização do JIG estético apresentou-se um método eficaz para restabelecer a DVO e auxiliar na confecção do enceramento de diagnóstico.

The occlusal vertical dimension (OVD) may be reduced when the occlusal relationship between posterior teeth collapses due to tooth loss, migrations or severe wear. The current case report aimed to present a technique to OVD reestablishment, named esthetic JIG. In this technique, a prefabricated tooth was adjusted on a maxillary central incisor to deter-mine the midline, incisors volume, incisal height and OVD increase. Through a digital planning and an esthetic JIG, the diagnostic wax-up was made and followed by the mock-up. The use of esthetic JIG showed to be an effective method for OVD reestablishment and to assist the waxing diagnostic.

Mechanical and biological complication rates of the modified lateral-screw-retained implant prosthesis in the posterior region: an alternative to the conventional Implant prosthetic system

PURPOSE: The modified lateral-screw-retained implant prosthesis (LSP) is designed to combine the advantages of screw- and cement-retained implant prostheses. This retrospective study evaluated the mechanical and biological complication rates of implant-supported single crowns (ISSCs) inserted with the modified LSP in the posterior region, and determined how these complication rates are affected by clinical factors. MATERIALS AND METHODS: Mechanical complications (i.e., lateral screw loosening [LSL], abutment screw loosening, lateral screw fracture, and ceramic fracture) and biological complications (i.e., peri-implant mucositis [PM] and peri-implantitis) were identified from the patients' treatment records, clinical photographs, periapical radiographs, panoramic radiographs, and clinical indices. The correlations between complication rates and the following clinical factors were determined: gender, age, position in the jaw, placement location, functional duration, clinical crown-to-implant length ratio, crown height space, and the use of a submerged or nonsubmerged placement procedure. RESULTS: Mechanical and biological complications were present in 25 of 73 ISSCs with the modified LSP. LSL (n=11) and PM (n=11) were the most common complications. The incidence of mechanical complications was significantly related to gender (P=.018). The other clinical factors were not significantly associated with mechanical and biological complication rates. CONCLUSION: Within the limitations of this study, the incidence of mechanical and biological complications in the posterior region was similar for both modified LSP and conventional implant prosthetic systems. In addition, the modified LSP is amenable to maintenance care, which facilitates the prevention and treatment of mechanical and biological complications.

Individualização em prótese dentogengival (IPD) em cerâmica: previsibilidade do projeto a realização das peças / Porcelain dentogingival prostheses customization (DPC): predictability from design to the manufacturing

A extração múltipla anterior causa consequências irreversíveis à anatomia do tecido gengival: o arco côncavo regular é perdido, as pontas das papilas passam a não mais existir, tornando a anatomia do rebordo remanescente retilínea. Podem-se realizar enxertos de tecidos ósseo e conjuntivo para aumento de volume, mas conseguir papilas pontiagudas, finas e longas é objetivo inalcançável, cuja consequência são próteses com dentes quadrados, em que se busca fechar os espaços negros formados pela ausência das papilas. O presente artigo revela aplicação da técnica de individualização em prótese dentogengival (IPD), para oferecer um tratamento personalizado com resultados esteticamente excelentes e melhor solução para casos estéticos com perda de tecido gengival...

Multiple teeth extraction in the anterior region causes irreversible consequences to gingival tissue anatomy: regular tissue architecture and papillae tips are lost, causing the tissue anatomy of the ridge to be flat. Bone or connective tissue graft may be performed for volume increase. However, achieving long and peaked papillae is nearly unreachable. The consequence is squared teeth, and the need to close the black holes formed from the absence of papillae. This article reveals the application of dentogingival prosthesis customization (DPC) technique, which the main goal is to offer a custom-made treatment with excellent aesthetic results which would be the best solution for aesthetic cases with loss of gingival tissue...

Implant-supported overdenture manufactured using CAD/CAM techniques to achieve horizontal path insertion between the primary and secondary structure: A clinical case report

This report describes the case of an edentulous patient with an atrophic maxilla and severe class III malocclusion. Prosthetic rehabilitation was performed using CAD/CAM techniques for manufacturing an implant-supported overdenture with horizontal insertion. A vestibulo-lingual insertion overdenture is a precision prosthesis with a fixation system affording a good fit between the primary and secondary structure. Both structures exhibit passive horizontal adjustment. This treatment option requires the same number of implants as implant-supported fixed dentures. The horizontal assembly system prevents the prosthesis from loosening or moving in response to axial and non-axial forces. The technique was used to rehabilitate a patient presenting an atrophic upper maxilla, with the insertion of 8 implants. No complications were reported at follow-up 3, 6 and 12 months after fitting of the prosthesis. This system offers solutions to the clinical and laboratory complications associated with hybrid prostheses, concealing emergence of the chimneys and improving implant-prosthesis hygiene.

Evaluation of biogeneric design techniques with CEREC CAD/CAM system

PURPOSE: The aim of this study was to evaluate occlusal contacts generated by 3 different biogeneric design modes (individual (BI), copy (BC), reference (BR)) of CEREC software and to assess the designs subjectively. MATERIALS AND METHODS: Ten pairs of maxillary and mandibular casts were obtained from full dentate individuals. Gypsum cast contacts were quantified with articulating paper and digital impressions were taken. Then, all ceramic crown preparation was performed on the left first molar teeth and digital impressions of prepared teeth were made. BI, BC, and BR crowns were designed. Occlusal images of designs including occlusal contacts were superimposed on the gypsum cast images and corresponding contacts were determined. Three designs were evaluated by the students. RESULTS: The results of the study revealed that there was significant difference among the number of contacts of gypsum cast and digital models (P<.05). The comparison of the percentage of virtual contacts of three crown designs which were identical to the contacts of original gypsum cast revealed that BI and BR designs showed significantly higher percentages of identical contacts compared with BC design (P<.05). Subjective assessment revealed that students generally found BI designs and BR designs natural regarding naturalness of fissure morphology and cusp shape and cusp tip position. For general occlusal morphology, student groups generally found BI design "too strong" or "perfect", BC design "too weak", and BR design "perfect". CONCLUSION: On a prepared tooth, three different biogeneric design modes of a CAD/CAM software reveals different crown designs regarding occlusal contacts and morphology.

Clinical evaluation of retained preload and cement washout in screw- and cement-retained implant prosthesis / 대한치과보철학회지

PURPOSE: The aim of this study was to evaluate the clinical performance of screw- and cement-retained implant prosthesis (SCP) design in terms of retained preload of abutment screws and cement washout. MATERIALS AND METHODS: Patients with the partial posterior edentulous areas comprised the study group. Implants were placed, and SCPs were delivered after 3 to 6 months healing. Follow-up examinations were performed. The implant survival rate and the prosthetic success rate were evaluated. The retained preload ratio of abutment screws and the prosthetic decementation ratio were measured. RESULTS: Twenty one SCPs (forty three implants)in twenty patients were followed up to 64 months. All of the implants survived during the follow-up period (mean follow-up: 34 months). The prosthetic success rate was 100 % considering no abutment, screw, porcelain or metal frame fractures, as well as no screw loosening. The retained preload ratio of SCPs at the end of follow-up period was 97.61% (+/-16.29) and the decementation ratio was 9.5 %. CONCLUSION: Within the limitations of this clinical study, SCP design showed favorable short-term clinical performances in respect of screw loosening and cement washout.

Precision of digital impressions with TRIOS under simulated intraoral impression taking conditions / 北京大学学报(医学版)

Objective:To evaluate the precision of digital impressions taken under simulated clinical impression taking conditions with TRIOS and to compare with the precision of extraoral digitalizations . Methods:Six #14 -#17 epoxy resin dentitions with extracted #16 tooth preparations embedded were made.For each artificial dentition , ( 1 ) a silicone rubber impression was taken with individual tray , poured with type IV plaster ,and digitalized with 3Shape D700 model scanner for 10 times;(2) fastened to a dental simulator , 10 digital impressions for each were taken with 3Shape TRIOS intraoral scanner .To assess the precision , best-fit algorithm and 3 D comparison were conducted between repeated scan models pairwise by Geomagic Qualify 12.0, exported as averaged errors (AE) and color-coded diagrams.Non-parametric analysis was performed to compare the precisions of digital impressions and model images .The color-coded diagrams were used to show the deviations distributions .Results:The mean of AE for digital impressions was 7.058 281 μm, which was greater than that of 4.092 363 μm for the model images (P<0.05).However, the means and medians of AE for digital impressions were no more than 10 μm, which meant that the consistency between the digital impressions was good .The deviations distribution was uniform in the model images ,while nonuniform in the digital impressions with greater deviations lay mainly around the shoulders and interproximal surfaces .Conclusion:Digital impressions with TRIOS are of good precision and up to the clinical standard .Shoulders and interproximal surfaces scanning are more difficult.

Planejamento e fabricação de restaurações implantossuportadas com processos odontológicos digitais / Digital planning and fabrication of implant-supported restorations

A Odontologia digital proporciona ao clínico novas possibilidades para planejar e fabricar as restaurações utilizadas na clínica diária. O planejamento virtual das restaurações é uma excelente ferramenta para prever o resultado final do tratamento, proporcionando maior segurança para o clínico e para o paciente. Este trabalho teve como objetivo descrever os passos do fluxo de trabalho necessário para a moldagem intraoral digital, planejamento virtual da restauração e fabricação pelo método CAD/CAM com o auxílio de um caso clínico em que o primeiro pré-molar superior foi restaurado. As arcadas digitalizadas foram utilizadas para planejar virtualmente as dimensões e os aspectos oclusais e estéticos da restauração, para a fabricação de modelo fresado das arcadas dentárias e para a posterior confecção da restauração com o auxílio do método CAD/CAM. Devido à digitalização de todos os passos até a confecção da prótese, a comunicação com o paciente foi facilitada, possibilitando a visualização adequada do proposto para a restauração. Pôde-se concluir que, uma vez dominado o uso da tecnologia digital, as restaurações podem ser consistentemente planejadas e fabricadas com o auxílio dos avançados métodos de fabricação atualmente disponíveis, levando a resultados altamente previsíveis e satisfatórios clinicamente.

Digital dentistry allows clinicians to design and fabricate predictable restorations for daily clinics. Virtual design of the restoration is an excellent tool to predict the fi nal outcome of the rehabilitation by the clinician and the patient. This study will describe the workflow for digital fabrication of dental restorations, including the digital intraoral impression, virtual design, and CAD/CAM fabrication of the restoration of a first maxillary premolar. The digital tooth arches were used to virtually plan the dimensions and the occlusal and esthetic aspects of the restoration. Milled dental models were also fabricated. Patient communication was improved by using the virtual design of the final restoration. It can be concluded that digital dentistry can allow the fabrication of consistent and highly predictable dental restorations.

Effect of veneering material on the deformation suffered by implant-supported fixed prosthesis framework

Knowing how stresses are dissipated on the fixed implant-supported complex allows adequate treatment planning and better choice of the materials used for prosthesis fabrication. Objectives: The aim of this study was to evaluate the deformation suffered by cantilevered implant-supported fixed prostheses frameworks cast in silver-palladium alloy and coated with two occlusal veneering materials: acrylic resin or porcelain. Material and Methods: Two strain gauges were bonded to the inferior surface of the silver-palladium framework and two other were bonded to the occlusal surface of the prosthesis framework covered with ceramic and acrylic resin on each of its two halves. The framework was fixed to a metallic master model and a 35.2 N compression force was applied to the cantilever at 10, 15 and 20 mm from the most distal implant. The measurements of deformation by compression and tension were obtained. The statistical 2-way ANOVA test was used for individual analysis of the experiment variables and the Tukey test was used for the interrelation between all the variables (material and distance of force application). Results: The results showed that both variables had influence on the studied factors (deformation by compression and tension). Conclusion: The ceramic coating provided greater rigidity to the assembly and therefore less distortion compared with the uncoated framework and with the resin-coated framework. The cantilever arm length also influenced the prosthesis rigidity, causing higher deformation the farther the load was applied from the last implant. .

Success and survival rates of mandibular overdentures supported by two or four implants: a systematic review

This systematic review evaluated the influence played by the number of implants on the results of rehabilitation treatment with mandibular overdentures on 2 or 4 implants. The literature search was conducted using PubMed, Embase and Cochrane databases. Specific terms were used in performing a search from January 1980 to January 2013. The search strategy was applied by two reviewers who extracted the data and compared the results. Discrepancies were resolved by discussion. Great heterogeneity was seen among the selected studies, in regard to survival rates, prosthesis failure and function rates. A medium degree of quality and methodological consistency was found in one study, and no studies showed a high degree. When considering the prosthesis success rate for 2 implants, there was a variation of 23% to 100%. However, when considering the survival rate, the result was 92% to 100%. For 4 implants, prosthesis survival rates showed less variation, i.e., 97.7% to 100%. Ball attachments were the most common type of abutment for 2 implants; however, there was a higher prevalence of bar abutments for 4 implants. Rehabilitations with 2 implants showed more complications and required more maintenance according to the connection type. Given the limitations of this review, mandibular overdentures with 4 implants showed better results with respect to survival and success rates, especially those with a bar connection. Further studies comparing these two treatment types are necessary to improve the scientific evidence in this area.

Intracanal post reinforcement in anterior teeth to prevent fractures / Uso do reforço intracanal em dentes anteriores na prevenção de fraturas tardias

Anterior tooth fracture after endodontic treatment is a real and multifactorial possibility because of root weakening due to tooth structure remnant loss and existing oblique occlusal forces. The fracture influenceson esthetics and causes masticatory dysfunction. Preventively, one of the treatments widely accepted is the use of intracanal posts made of metal, carbon fiber, fiberglass and ceramics. The metal and carbon fiber posts are very efficient but do not favor esthetics, while the fiberglass and ceramics posts are both durable and aesthetics. The reinforcement with these biomaterials is advantageous and leads to a favorable prognosis. This study showed a case in which intracanal reinforcement could have prevented the fracture of a devitalized maxillary anterior tooth and provided a brief discussion about the available options for this type of rehabilitation. The use of glass fiber reinforcement posts fordevitalized tooth structure is indicated to prevent dental fractures. Ceramic posts have been indicated in cases with insufficient coronal remaining to support thecore material.

A fratura de dentes anteriores após tratamento endodôntico é uma possibilidade real e multifatorial. Isso se deve ao enfraquecimento da raiz devido à perda do remanescente dental somado às forças oclusais oblíquas existentes. Esta fratura influencia a estética do paciente além de causar disfunção mastigatória. Na prevenção, um dos tratamentos utilizados e muito bem aceitos, é o uso de pinos intra-radiculares. Estes podem ser confeccionados em metais, fibra de carbono, fibra de vidro e em cerâmica. Os pinos de metal e de fibra de carbono são muito eficientes, porém não favorecem a estética, enquanto que os pinos de fibra de vidro e os de cerâmica são resistentes e favorecerem a estética. O reforço com esses biomateriais é vantajosos e leva a um prognóstico favorável. O presente estudo apresenta um caso clínico onde o reforço intracanal poderia ter prevenido a fratura de um dente ântero-superior desvitalizado e realiza uma breve discussão acerca das opções disponíveis para este tipo de reabilitação. O uso de pinos de fibra de vidro como reforço da estrutura de dentes desvitalizados é indicado na prevenção de fraturas dentárias, porém núcleos cerâmicos fundidos são indicados para remanescentes coronários insuficientes para suportar o material de preenchimento.

Connecting accuracy of interchanged prosthetic abutments to different dental implants using scanning electron microscopy

The present study evaluated the interchangeability of prosthetic components for external hexagon implants by measuring the precision of the implant/abutment (I/A) interface with scanning electron microscopy. Ten implants for each of three brands (SIN, Conexão, Neodent) were tested with their respective abutments (milled CoCr collar rotational and non-rotational) and another of an alternative manufacturer (Microplant) in randomly arranged I/A combinations. The degree of interchangeability between the various brands of components was defined using the original abutment interface gap with its respective implant as the benchmark dimension. Accordingly, when the result for a given component placed on an implant was equal to or smaller then that gap measured when the original component of the same brand as the implant was positioned, interchangeability was considered valid. Data were compared with the Kruskal-Wallis test at 5% significance level. Some degree of misfit was observed in all specimens. Generally, the non-rotational component was more accurate than its rotational counterpart. The latter samples ranged from 0.6-16.9 µm, with a 4.6 µm median; and the former from 0.3-12.9 µm, with a 3.4 µm median. Specimens with the abutment and fixture from Conexão had larger microgap than the original set for SIN and Neodent (p<0.05). Even though the latter systems had similar results with their respective components, their interchanged abutments did not reproduce the original accuracy. The results suggest that the alternative brand abutment would have compatibility with all systems while the other brands were not completely interchangeable.

O presente estudo avaliou a intercambiabilidade dos componentes protéticos de implantes de hexágono externo medindo-se a precisão da interface implante/pilar com microscopia eletrônica de varredura. Foram utilizados dez implantes para cada uma de três marcas (SIN, Conexão, Neodent) com seus respectivos pilares (base metálica de CoCr , rotacional e não rotacional) e um de marca alternativa (Microplant) em um arranjo com todas as combinações de implante/pilar possíveis. O valor de referência para a intercambiabilidade das várias marcas de componentes foi definido pela diferença do pilar original para com seu respectivo implante. Dessa maneira, a intercambiabilidade foi considerada válida quando o resultado para um dado pilar colocado sobre um implante fosse igual ou menor que a diferença medida quando o pilar da mesma marca do implante fora posicionado. Os dados foram comparados pelo teste de Kruskal-Wallis com nível de significância de 5%. Um grau de desajuste foi observado em todos os espécimes. De uma maneira geral, o pilar anti-rotacional foi mais preciso do que o rotacional. Estes variaram de 0,6-16,9 µm, com mediana 4,6 µm; enquanto o anti-rotacional foi de 0,3-12,9 µm, com mediana de 3,4 µm. Os espécimes com o pilar e o implante Conexão tiveram uma diferença maior que o conjunto original para SIN e Neodent (p<0,05). Apesar destes últimos apresentarem resultados semelhantes com seus respectivos pilares, quando trocados não mantiveram a mesma precisão original. Os resultados sugerem que a marca alternativa seria a única que apresentaria compatibilidade com todos os sistemas, enquanto as outras marcas não seriam completamente intercambiáveis.

Seleção do sistema cerâmico na reabilitação estética anterior: relato de caso / Selection of the ceramic system in esthetic rehabilitation: case report

Problemas estéticos relacionados ao sistema metalocerâmico têm impulsionado o desenvolvimento dos sistemas conhecidos como totalmente cerâmicos e que atualmente podem ser considerados a primeira alternativa no tratamento restaurador para próteses unitárias e fixas. O desafio está em conhecer as propriedades de cada um desses sistemas, uma vez que não há, até o momento, um único sistema cerâmico que possa ser empregado em qualquer situação clínica. Este artigo descreve as razões que guiaram a seleção da cerâmica IPS e.max Press à base de dissilicato de lítio, assim como os principais procedimentos clínicos empregados para a reabilitação estética

Esthetic concerns related to porcelain-fused-to-metal restorations driven the development of ceramic systems. Currently, these all-ceramic systems can be regard as the first alternative in the restorative treatment, including unitary and multiple prostheses. Understanding the mechanical and esthetic properties of each material is challenging, since no system can be used for all clinical conditions up to date. This article describes the principles that guide selection of a lithium dissilicate ceramics (IPS e.max Press) as well as the main clinical steps, involved in the rehabilitation of a patient esthetic compromised in the anterior teeth