Prevalencia de cristales de colesterol en granulomas perirradiculares de origen endodóntico / Prevalence of cholesterol crystals in periradicular granulomas of endodontic origin

Resumen Objetivo Comparar dos procedimientos de soldadura convencionales empleando una aleación de Cr-Co, para conectar barras coladas seccionadas a ser fijadas sobre implantes. Materiales y métodos A partir de un modelo maestro que representa un maxilar desdentado con cuatro implantes, se confeccionaron veinte (n=20) probetas seccionadas en tres partes. Se conformaron dos grupos, cada uno con diez (n=10) ejemplares. Una vez acondicionadas, fueron atornilladas al modelo maestro. Su desajuste inicial se analizó utilizando una lupa estereoscópica, con una cámara incorporada y un software. Las partes fueron soldadas empleando un procedimiento diferente para cada grupo. Las correspondientes al Grupo I se invistieron en un block refractario a base de sílico-fosfato. Las del Grupo II se montaron en una estructura metálica Clever Spider. El desajuste fue mensurado y los resultados procesados estadísticamente. El nivel de significación fue establecido en p<0,05. Resultados El Grupo I tuvo un desajuste inicial de 97,30±13,81μm y el Grupo II de 98,53±11,24μm. Luego de la soldadura, el Grupo I registró 98,53±17,17μm, 1,23μm mayor respecto al inicial. En el Grupo II se observó 103,13±17,61μm, 4,60μm por encima del original. Se analizaron mediante prueba t de Student; en ambos casos el resultado fue de p>0,05. Al comparar entre sí los grupos I y II, por medio de la prueba t y de comprobación no paramétrica de Mann-Whitney, se observaron diferencias no significativas, p=0,41 y p=0,38 respectivamente. Conclusiones Bajo las condiciones de este estudio, se observó que los dos métodos de soldadura analizados fueron confiables para unir supraestructurasos metálicas sin que se afecte su ajuste final.

Abstract Aim Compare two conventional welding procedures using a Cr-Co alloy, to connect sectioned cast bars to be fixed on implants. Materials and methods From a master model representing a toothless jaw with four implants, twenty (n=20) specimens sectioned into three parts were made. Two groups were formed, each with ten (n=10) specimens. Once conditioned, they were screwed to the master model. Its initial mismatch was analyzed using a stereoscopic magnifier, with a built-in camera and a software. The parts were welded using a different procedure for each group. Those corresponding to Group I were invested in a refractory block based on silyl-phosphate. Those of Group II were mounted on a Clever Spider metal structure. The mismatch was measured, and the results processed statistically. The level of significance was established at p<0.05. Results Group I had an initial mismatch of 97.30 ±13.81μm, and Group II of 98.53±11.24μm. After welding, Group I registered 98.53±17.17μm, 1.23μm higher than the initial one. In Group II, 103.13±17.61μm was observed, 4.60μm above the original. They were analyzed using Student's t test; in both cases the result was p>0.05. When comparing groups I and II, using the t-test and the Mann-Whitney nonparametric verification, non-significant differences were observed, p=0.41 and p=0.38 respectively. Conclusions Under the conditions of this study, it was observed that the two welding methods analyzed were reliable for joining metallic superstructures without affecting their final fit.

Estudio in vitro del ajuste de supraestructuras pasivadas sobre implantes múltiples / In vitro study of the adjustment of passivated suprastructures on multiple implants

Resumen Objetivo Comparar dos procedimientos de soldadura convencionales empleando una aleación de Cr-Co, para conectar barras coladas seccionadas a ser fijadas sobre implantes. Materiales y métodos A partir de un modelo maestro que representa un maxilar desdentado con cuatro implantes, se confeccionaron veinte (n=20) probetas seccionadas en tres partes. Se conformaron dos grupos, cada uno con diez (n=10) ejemplares. Una vez acondicionadas, fueron atornilladas al modelo maestro. Su desajuste inicial se analizó utilizando una lupa estereoscópica, con una cámara incorporada y un software. Las partes fueron soldadas empleando un procedimiento diferente para cada grupo. Las correspondientes al Grupo I se invistieron en un block refractario a base de sílico-fosfato. Las del Grupo II se montaron en una estructura metálica Clever Spider. El desajuste fue mensurado y los resultados procesados estadísticamente. El nivel de significación fue establecido en p<0,05. Resultados El Grupo I tuvo un desajuste inicial de 97,30±13,81μm y el Grupo II de 98,53±11,24μm. Luego de la soldadura, el Grupo I registró 98,53±17,17μm, 1,23μm mayor respecto al inicial. En el Grupo II se observó 103,13±17,61μm, 4,60μm por encima del original. Se analizaron mediante prueba t de Student; en ambos casos el resultado fue de p>0,05. Al comparar entre sí los grupos I y II, por medio de la prueba t y de comprobación no paramétrica de Mann-Whitney, se observaron diferencias no significativas, p=0,41 y p=0,38 respectivamente. Conclusiones Bajo las condiciones de este estudio, se observó que los dos métodos de soldadura analizados fueron confiables para unir supraestructurasos metálicas sin que se afecte su ajuste final.

Abstract Aim Compare two conventional welding procedures using a Cr-Co alloy, to connect sectioned cast bars to be fixed on implants. Materials and methods From a master model representing a toothless jaw with four implants, twenty (n=20) specimens sectioned into three parts were made. Two groups were formed, each with ten (n=10) specimens. Once conditioned, they were screwed to the master model. Its initial mismatch was analyzed using a stereoscopic magnifier, with a built-in camera and a software. The parts were welded using a different procedure for each group. Those corresponding to Group I were invested in a refractory block based on silyl-phosphate. Those of Group II were mounted on a Clever Spider metal structure. The mismatch was measured, and the results processed statistically. The level of significance was established at p<0.05. Results Group I had an initial mismatch of 97.30 ±13.81μm, and Group II of 98.53±11.24μm. After welding, Group I registered 98.53±17.17μm, 1.23μm higher than the initial one. In Group II, 103.13±17.61μm was observed, 4.60μm above the original. They were analyzed using Student's t test; in both cases the result was p>0.05. When comparing groups I and II, using the t-test and the Mann-Whitney nonparametric verification, non-significant differences were observed, p=0.41 and p=0.38 respectively. Conclusions Under the conditions of this study, it was observed that the two welding methods analyzed were reliable for joining metallic superstructures without affecting their final fit.

Preparation of ICD and overdenture in patients with Cushing's Syndrome: five-year follow-up / Preparo de PTI e overdenture em pacientes com Síndrome de Cushing: cinco anos de acompanhamento

The aim of this study is to report a clinical case of a patient with Cushing's syndrome, low self-esteem and need for oral rehabilitation. A 50-year-old female patient with hypercortisolism sought care at School of Dentistry of the Federal University of Minas Gerais. During anamnesis, the patient reported painful symptoms and mobility of the upper and lower teeth. On clinical examination, absence of many teeth were observed, periodontal disease and caries lesions. After discussion of the case, the planning involved the extraction of all teeth, and the preparation of Maxillary Immediate Complete Dentures (ICD's) and Immediate Mandibular Implant-retained Overdenture (IMIO). The treatment proposed allowed the restored aesthetics, phonetics and chewing(AU)

O objetivo desse estudo é relatar um caso clínico de uma paciente com síndrome de Cushing, baixa autoestima e necessidade de reabilitação oral. Paciente do sexo feminino, 50 anos de idade e com hipercortisolismo, procurou atendimento na Faculdade de Odontologia da Universidade Federal de Minas Gerais. Durante a anamnese, a paciente relatou sintomas dolorosos e mobilidade dos dentes superiores e inferiores. No exame clínico, foi observada a ausência de muitos dentes, doença periodontal e lesões cariosas. Após a discussão do caso, o planejamento envolveu a extração de todos os dentes, e o preparo de Prótese Total Imediata maxilar (PTI), e Overdenture Implantorretida Imediata mandibular. O tratamento proposto permitiu que restaurasse a estética, fonética e mastigação(AU)

Sobredentadura parcial como alternativa de tratamiento en paciente con secuela periodontal. Reporte de caso

La rehabilitación de pacientes desdentados parciales periodontalmente comprometidos es un desafío a nivel protésico. Esto se debe a que la condición de los dientes pilares no siempre es la adecuada, viéndose afectada la proporción corono-radicular por las secuelas de una enfermedad periodontal. Es en estas situaciones límite donde el uso de implantes óseo-integrados acompañado de ataches resilientes mejora la retención de una prótesis parcial removible convencional, disminuyendo el riesgo de sobrecarga en los dientes remanentes. En este reporte de caso se presenta una rehabilitación integral, resuelto con una sobredentadura parcial maxilar sin cobertura palatina sobre pilares Locator®, minimizando la carga en los dientes remanentes del grupo II con secuelas periodontales; y una rehabilitación del arco mandibular con operatoria directa, indirecta y prótesis fija, recuperando funcionalidad, soporte oclusal y manteniendo los dientes remanentes en el sector anterior.

Rehabilitation of periodontally compromised partially edentulous patients has always been a challenge at the prosthetic level, because the condition of the remaining teeth is not always adequate and the crown-root ratio is often affected by the sequelae of periodontal disease. In these borderline situations, the use of osseointegrated implants accompanied by resilient attachments improves the retention of a conventional removable partial denture, reducing the risk of overloading the remaining teeth. This case report presents a comprehensive rehabilitation, resolved with a maxillary partial overdenture without palatal coverage on Locator® abutments, minimizing the load on the remaining pieces of group II with periodontal sequelae; and a rehabilitation of the mandibular arch with direct, indirect and fixed prosthesis. In this way, it was possible to recover functionality, occlusal support and keep the remaining teeth in the front part of the maxilla.

Tratamiento protésico con sobredentadura en un anciano / Prosthetic treatment with overdenture in an elderly

Se describe el caso clínico de un anciano de 63 años de edad, con color de la piel mestizo y buena salud general, quien acudió a consulta de Prótesis Dental en la Clínica Estomatológica Provincial Docente Mártires del Moncada de Santiago de Cuba porque se encontraba afectado estéticamente y, además, deseaba preservar sus dientes remanentes; refirió que no había recibido tratamiento protésico previo. Luego de efectuar exámenes bucodental y complementarios, así como otros procedimientos odontológicos, se decidió rehabilitar con sobredentadura para conservar los dientes pilares, restablecer las funciones perdidas y mejorar la estética. El paciente fue rehabilitado estética y funcionalmente y mostró una evolución satisfactoria.

The case report of a half blood 63 years elderly with good general health, who visited the Dental Prosthesis Service in the Mártires del Moncada Teaching Provincial Estomatological Clinic in Santiago de Cuba is described, as he was esthetically affected and, he wished to preserve his remanent teeth; he informed that he had not received any previous prosthetic treatment. After making oral and dental exploration and other exams, as well as other odontological procedures, it was decided to rehabilitate him with overdentures to preserve the abutment teeth, to reestablish the lost functions and to improve esthetics. The patient was rehabilitated esthetically and functionally and he showed a satisfactory clinical course.

Sobrevida, éxito, y efecto en la calidad de vida del tratamiento con sobredentadura mandibular en el Servicio de Especialidades Dentales, Hospital Clínico San Borja Arriarán, Chile: estudio clínico prospectivo de 11 casos. Parte I

RESUMEN: En los hospitales públicos chilenos, los pacientes desdentados mandibulares pueden ser tratados con una Sobredentadura-Mucosoportada, Implanto-Retenida (SMIR). Para tal fin, se adaptaron los lineamientos del plan piloto "Programa de Prestaciones Valoradas. Odontología 2012 Ministerio de Salud", en ausencia de una Guía Ministerial. El objetivo de esta serie de casos fue evaluar si la implementación y adaptación del plan piloto del tratamiento con SMIR mejoró la calidad de vida de los pacientes. Se evaluaron sobrevida, éxito implantario, e impacto en la calidad de vida. Los resultados indican una sobrevida y éxito implantario del 100% y una mejora de la calidad de vida. Conclusión: el tratamiento con SMIR mejora la calidad de vida de los pacientes, en el servicio público.

ABSTRACT: In Chilean public hospitals, patients with Complete Edentulous Mandible are treated with Implant-Retained and Mucosa-supported Overdenture (IRMO). For this purpose, the guidelines of the pilot plan "Valued Benefits Program in Dentistry 2012, Ministry of Health" have been adapted. The aim of this study was to evaluate whether these adapted protocols have been successful. We measured implant survival and success, and impact on quality of life with OHIP-14 criteria. Results indicate 100% implant survival and success and improved quality of life. Conclusion: IRMO improves patients' quality of life in public services.

Qualitative evaluation of immediate rehabilitation: a case report with 5 years of follow-up / Avaliação qualitativa de reabilitação imediata: relato de caso com 5 anos de acompanhamento

Próteses totais imediatas e overdentures mandibulares em carga imediata, são boas alternativas para restaurar a função e a estética. Além disso, proporcionam um fator psicológico positivo, eliminando as consequências emocionais e sociais da perda dos dentes. O objetivo deste estudo foi relatar um caso clínico, com cinco anos de acompanhamento, utilizando parâmetros clínicos e ferramentas qualitativas, para analisar o impacto na qualidade de vida do paciente e no sucesso do tratamento. Este caso clínico foi desenvolvido em um projeto assistencial da Faculdade de Odontologia da Universidade Federal de Minas Gerais, Brasil, que promove a reabilitação oral de pacientes de baixa renda com dentes severamente comprometidos. Paciente do sexo masculino, 57 anos, apresentou-se para tratamento com condição severa de saúde dental e periodontal. O plano de tratamento proposto foi a extração dos dentes remanescentes e confecção de prótese total imediata maxilar e overdenture mandibular, em carga imediata, sobre implantes. O paciente foi acompanhado periodicamente, a cada seis meses, para substituição do o´rings, conforme recomendação do fabricante. Após 5 anos, as próteses foram reembasadas com resina acrílica termopolimerizável e os componentes protéticos da overdenture foram substituídos. Em um acompanhamento qualitativo, a equipe utilizou uma entrevista narrativa, com foco nos impactos do tratamento na qualidade de vida desse paciente. Ele confirmou, em um relato em primeira pessoa, sua satisfação com o tratamento realizado e a melhora nas relações sociais, afetivas e no trabalho, mostrando como a reconquista do sorriso pode transformar a experiência pessoal do indivíduo(AU)

Immediate complete dentures and mandibular immediately loaded overdentures are good alternatives to restore function and aesthetics. Moreover, they provide positive psychological factor, eliminating the emotional and social consequences of tooth loss. The aim of this study was to report a clinical case, with five years of follow-up using clinical parameters and qualitative tools, to analyze the impact on quality of life and the success of treatment. This clinical case was developed in an assistance project of the Dental School of Federal University of Minas Gerais in Brazil, which promotes oral rehabilitation of low-income patients with severely damaged dentitions. A 57-yearold male patient presented for treatment with a severe dental and periodontal health condition. The proposed treatment plan was extraction of the remaining teeth and making maxillary immediate complete denture and mandibular immediately loaded implant-supported overdenture. The patient was monitored periodically, every six months, to replace the polymer ring ball attachment, according to the manufacturer's recommendation. After 5 years, the prostheses were relining with heat-polymerized acrylic resin and overdenture prosthetic components were replaced. In a qualitative follow-up, the team used a narrative interview, focusing on the impacts of treatment in the quality of life of this patient. He confirms, in a firstperson account, his satisfaction with the treatment performed and improvements in social and affective relations and in the work, showing how the reconquest of the smile can transform the personal experience of the individual(AU)

Implant Supported Overdenture - A Review

Background:Traditional complete dentures were the most common treatment option for patients with edentulous arches. However, the initiation of implant-supported overdentures has substitutedorthodox dentures as animproved standard for restoration. Careful case selection is important criteria for improving success rate of implant supported over denture. Lower arch implant-supported overdentures have a better success percentage than upper arch implant-supported overdentures. Upper arch implant-supported overdentures are simulating a form of “salvage treatment,” rather than being the primary modality of treatment for patients with completely edentulous upper arch.

The effect of attachment types and implant level on the stress distribution in a mandibular overdenture: a 3D Finite Element Analysis / O efeito dos tipos de sistemas de retenção e nível dos implantes na distribuição de tensões em overdentures mandibulares: Análise por Elementos Finitos 3D

Objective: The objective of this study was to evaluate the stress distribution in bone-surrounding implants placed in different levels in a mandibular overdenture. Material and Methods: A Computerized Tomography (CT) scan of an edentulous mandible was used to generate the models. Two implants with an internal connection were placed perpendicular to the occlusal plane in the Canine sites of the mandible. The implant in the left side was placed 1mm higher than the other side. Dolder bar and ball attachments were designed. Loading was performed by clenching the teeth with reconstruction of the muscles. In the anterior loading condition, force was applied to the central incisors and in the posterior loading conditions, it was applied to the molars and premolars. Then the Maximum Principal Stresses in the peri implant bone was evaluated with finite element analysis. Results:In both models, the highest stress values were recorded in the cortical bone surrounding the higher implant except in the ball model with unilateral load application on the right side (64.7 MPa). In almost all loading conditions the stress value differences in models with bar and ball attachments were low. Only in the anterior loading condition, the stress magnitude was higher in two implants of the ball model (60.5 MPa in the left side and 21 MPa in the right side) compared to the bar model (54.5 MPa in the left side and 17.5 MPa in the right side). Conclusion: The stress concentration did not affected considerably by the attachment system. High stress values were found adjacent the implant with a higher level. To reduce the amount of stress, bilateral balance occlusion should be considered. (AU)

Objetivo: O objetivo deste estudo foi avaliar a distribuição de tensões em tecido ósseo ao redor de implantes instalados em diferentes níveis em uma Overdenture mandibular. Material e Métodos: Uma tomografia computadorizada (TC) de uma mandíbula edêntula foi usada para gerar os modelos. Dois implantes de conexão interna foram instalados perpendicularmente ao plano oclusal na região de caninos inferiores. O implante do lado esquerdo foi instalado 1mm acima do que do lado direito. A barra Dolder e o pilar tipo bola foram projetados. A carga foi realizada apertando os dentes com reconstrução dos músculos. Na condição de carga anterior, a força foi aplicada nos incisivos centrais e nas condições de carga posterior, foi aplicada nos molares e pré-molares. Em seguida, as Tensões Máximas Principais no osso periimplantar foram avaliadas com análise de elementos finitos. Resultados: Em ambos os modelos, os maiores valores de tensão foram registrados ao redor do osso cortical ao redor do implante superior, exceto no modelo tipo bola com aplicação de carga unilateral no lado direito (64,7 MPa). Em quase todas as condições de carregamento, as diferenças nos valores de tensão nos modelos com fixações de barra e tipo bola foram baixas. Apenas na condição de carregamento anterior, a magnitude da tensão foi maior em dois implantes do modelo tipo bola (60,5 MPa no lado esquerdo e 21 MPa no lado direito) em relação ao modelo barra (54,5 MPa no lado esquerdo e 17,5 MPa no lado direito). Conclusão:A concentração de tensão não foi afetada considerando o sistema de retenção. Maiores valores de tensão foram encontrados adjacentes ao implante com um nível mais alto. Para reduzir a quantidade de tensão, a oclusão bilateral balanceada deve ser considerada.(AU)

Research progress on the effect of implant-supported overdentures on residual ridges / 口腔疾病防治

@#With the growing maturity of implant technology, implant overdenture has gradually become a conventional repair method for edentulous patients to restore beauty and function, which improves the quality of life of edentulous patients. This paper reviews the effects of implant factors, attachment factors, occlusal factors and patients' own factors on residual alveolar ridge. Existing studies suggest that when designing denture, doctors first need to consider the oral mucosa and jaw conditions of patients before operation, and select the appropriate size of implant to ensure that sufficient bone remains around the implant; Secondly, when choosing the type of attachment, the number, location and A-P distance of implants should be fully considered, and the inclination of cusp should be properly reduced to avoid the harm of excessive lateral force to alveolar ridge; Finally, regular reexamination should be carried out after operation to maintain longer service time of denture and more sufficient bone mass of edentulous patients. However, there are many factors affecting jaw absorption. In the future, we should further explore many factors, such as patients' habit and frequency of wearing dentures, oral health and nutritional status, systemic diseases and medication.

Overdentures as an alternative to conventional dentures: a micro-costing analysis for Public Health Service in Brazil / Overdentures como alternativa às próteses convencionais: uma análise de micro-custeio para o Sistema Único de Saúde

Abstract This study aimed to estimate cost and compatibility with public financial incentives of two technologies for treating the edentulous mandible: lower complete dentures (CD) and overdentures retained by two dental implants (OD). This study consisted of a partial economic evaluation, with a micro-costing bottom-up approach for the calculation of direct costs. The estimates involved the number of consultations, proportion of materials, equipment, instruments' lifetime, and human resources, described in the price panel website of the Ministry of Economy in Brazil. Complementary information was obtained from a panel of experts. A sensitivity analysis was based on 20% variation. The estimated cost of a CD was R$ 189.89 (base scenario), and this varied between R$ 151.91 and R$ 227.89 according to sensibility analysis. The cost of an OD was R$ 663.05 (ranging from R$ 795.66 to R$ 530.44 - 1US=R$ 3.80/July 2019). The Ministry of Health covers appropriately the costs of the CD and OD. Both technologies showed costs that are within the limits of financial public incentives obtained by municipalities. The technologies are economically viable and should be induced through public policies due to their positive impacts on several functional domains of health.

Resumo Estimar os custos e a compatibilidade dos incentivos públicos de duas tecnologias para o tratamento da mandíbula edêntula: prótese total convencional (PTC) e overdenture retida por dois implantes (OD). Este estudo consistiu em uma avaliação econômica parcial, com abordagem "bottom-up" para o cálculo dos custos diretos. As estimativas levaram em consideração o número de consultas, proporção de materiais, equipamentos, vida útil dos instrumentais e recursos humanos. Os custos foram baseados no painel de preços do Ministério da Economia do Brasil e informações complementares foram obtidas de um painel de especialistas. Uma análise de sensibilidade foi baseada na variação de 20% dos custos. Os custos da PTC foram estimados em R$ 189,89 (cenário base) com variação entre R$ 151,91 e R$ 227,89 na análise de sensibilidade. Os custos da OD foram R$ 663,05 (variando de R$ 795,66 a R$ 530,44). O Ministério da Saúde cobre apropriadamente os custos de ambas as tecnologias nos cenários base e mais otimista. Ambas as tecnologias apresentaram custos dentro dos limites dos incentivos públicos recebidos. As tecnologias são economicamente viáveis e devem ser induzidas por políticas públicas diante do impacto positivo em vários domínios funcionais da saúde.

Interarch distance is a target restorative space value: clinical decisionmaking of implant restoration guided by measured value / 华西口腔医学杂志

When design an implant restoration for edentulous patients, many doctors ignore the sufficiency of the interarch distance (vertical distance) or horizontal distance of the patient to accommodate the superstructure and restoration before designing the implant plan. However, the connotation of measuring the interarch distance or horizontal distance has not been clarified in clinical practice. It is often based on visual estimation after operation, and the decision-making path of implant restoration is inverted, resulting in many mistakes regarding the restoration after implantation. The main reason is the lack of standardized paths and practical methods to use before surgery. This article recommended initially establishing a maxillo-mandibular relationship based on natural teeth, old dentures, or new ones and then using the height and horizontal distance or angle of the target restorative space, which was easier to grasp as the measured index. The minimum vertical distance (including the height of the gingival surface and the bone surface) and the horizontal distance (or the angle from the bone or gingival surface to the proposed occlusal plane) should be measured before operation. A decision tree of edentulous jaw restoration guided by the values of the repair space was established based on the measured values. This article clarified the measuring points and planes and thus provided a quantitative relationship basis for the design of implant restoration.

Análisis retrospectivo de implantes para sobredentaduras en maxilar inferior, en el marco de la formación de recursos humanos / Retrospective analysis of dental implants placed in the lower jaw, within the post graduate dental training framework

Objetivo: Evaluar el porcentaje de implantes oseointegrados colocados en pacientes edéntulos para la confección de sobredentaduras inferiores, en el marco de la formación de recursos humanos. Materiales y métodos: Se analizaron las historias clínicas de los pacientes que recibieron dos implantes dentales inferiores para la confección de sobredentaduras en el servicio de residentes de la carrera de Especialización en Cirugía y Traumatología Bucomaxilofacial de la Facultad de Odontología de la Universidad de Buenos Aires, entre agosto de 2012 y diciembre de 2018. Se consideraron para el análisis el porcentaje de implantes oseointegrados y su relación con el tipo de operador (docente o residente), la situación del reborde óseo y el hábito de fumar. Resultados: De los 176 implantes colocados en 88 pacientes (edad promedio = 67 años), a los 3-4 meses el 98% (IC95: 94-99%) se hallaba oseointegrado. No se encontró una relación estadísticamente significativa entre el tipo de operador y el fracaso (P>0,99) Conclusión: En un servicio de formación, la tasa de éxito, evaluada en la segunda cirugía, de dos implantes dentales colocados en el maxilar inferior para sobredentaduras fue de 98%. No se hallaron diferencias entre los resultados logrados por residentes y docentes del servicio (AU)

Aim: To evaluate the percentage of osseointegrated im- plants placed in edentulous patients to restore with mandib- ular overdentures, within the post graduate dental training framework. Materials and methods: Medical records of patients who received two dental implants in the mandible for the placement of overdentures in the resident clinic of the special- ization career in Oral and Maxillofacial Surgery and Trauma- tology from the Facultad de Odontología de la Universidad de Buenos Aires, between August 2012 and December 2018. The percentage of osseointegrated implants was analysed, and the association with the variables: operator (teacher or resident), mediate or immediate placement, and smoking. Results: 176 implants were placed in 88 patients with an average age of 67 years old. 98% (IC95: 94-99%) of the implants were osseointegrated at 3-4 months. No statistically significant association was detected between the type of oper- ator and implant failure (P>0.99). Conclusion: In the teaching dental training clinic, the success rate, evaluated at the second implant stage surgery, of two dental implants placed in the mandibule for overden- tures was 98%. No differences were found between the results achieved by residents and teachers (AU)

Effect of cleanser solutions on the retention force of oring attachment: an in vitro study

Abstract The aim of this study was to evaluate the effect of cleaning solutions on the retention force of o-ring-type overdenture attachments. The effect of four solutions on nitrile rings were evaluated: Cepacol (C), Cepacol with fluoride (CF), Listerine (L) and 0.05% sodium hypochlorite (SH); deionized water (DW) was used as a control. Matrices containing two implants and abutments and acrylic specimens with the metal capsules were obtained and divided into the groups. A simulation of 90 overnight immersions (8 h) was performed, and the tensile strength value was obtained at the beginning (T0) and in every 30 days (T1, T2 and T3) (n=6). In order to analyze o-ring surface damage after the immersions, a scanning electron microscopy (SEM) was used (n=1). For statistical analysis of the results, analysis of variance (ANOVA) and multiple comparisons with Bonferroni adjustment (test power=1.000; a=0.05) were used. There was a significant difference for the factors time (p<0.001), solution (p<0.001) and for the interaction time × solution (p<0.001). Considering the times of each solution, only for DW there was no significant loss of retention over time. Comparing the solutions in each moment, there was no difference among the solutions in T0. From T1, CF and SH provided less retention than DW (p<0.005). Through SEM it was possible to observe changes in the surface of the CF and SH nitrile o-rings. CF and SH should be avoided due to deleterious action in o-rings.

Resumo O objetivo do estudo foi avaliar o efeito de soluções higienizadoras sobre a força de retenção de encaixes do tipo o-ring. Foram avaliadas quatro soluções: Cepacol (C); Cepacol com flúor (CF), Listerine (L), hipoclorito de sódio 0,05% (HS) e água deionizada (controle/AD) em o-rings de nitrilo. Matrizes contendo dois implantes e pilares e espécimes em acrílico com as cápsulas metálicas foram obtidas e divididas entre os grupos. Foi realizada a simulação de 90 imersões noturnas (8 h), sendo obtido o valor da resistência à tração no início e a cada 30 dias (T0, T1, T2 e T3) por meio da máquina de ensaios mecânicos (n=6). Microscopia eletrônica de varredura (MEV) foi utilizada para análise de danos na superfície do o´ring após a imersão (n=1). Para análise estatística dos resultados foi utilizada análise de variância (ANOVA) e múltiplas comparações com ajuste de Bonferroni (poder do teste=1,000; a=0,05). Houve diferença significante para os fatores tempo (p<0,001), solução (p<0,001) e para interação de tempo × solução (p<0,001). Considerando-se os tempos de cada solução, apenas AD não apresentou perda significativa de retenção ao longo do tempo. Comparando as soluções em cada momento, não houve diferença entre as soluções em T0. A partir de T1, CF e HS propiciaram menor retenção quando comparados à AD (p <0,005). Através do MEV foi possível observar alterações nas superfícies dos o-rings de nitrilo imersos em CF e HS. O Cepacol com flúor e hipoclorito de sódio devem ser evitados devido à ação deletéria nos o-rings.

Observation of the effect on immediate mandibular implant-supported overdenture of micro implant system of Italy / Observação do efeito na sobredentadura imediata mandibular suportada por implante do sistema de micro implante da Itália

The study was design to investigate the clinical effect of Micro implant system in Italy on immediate mandibular implant-supported overdenture. A total of 192 patients with mandibular edentulous treated in our hospital were randomly divided into 2 groups in which the control group consisted of 96 patients treated with immediate mandibular implant-supported overdenture by Xive implant system, while the observation group included 96 cases treated with the overdenture by Italy Micro implant system. Patients were followed up for 1 year and then the states of implant-borne overdentures, marginal bone resorption around alveolar bone, the compatibility of implant restorations with adjacent teeth, adverse events and satisfaction degree were compared between the groups. According to the results of 1-year follow-up, the resorption around alveolar bone of the observation group was significantly higher than that of the control group (p<0.05). In the observation group the differences in labial gingival margin position, gingival color and texture were significantly better (p<0.05) as compared to control group. The incidence of adverse events was notably lower (p<0.05). The Italy Micro implant system has significant curative effect on mandibular implant-supported overdentures with good compatibility of the implant restorations with adjacent teeth and low incidence rate of adverse reactions, so it is worthy of clinical application and spreading.

O estudo foi desenvolvido para investigar o efeito clínico do sistema de implantes de B&B na Itália na prótese total imediata apoiada em implante mandibular. Um total de 192 pacientes com desdentação mandibular, tratados em nosso hospital foram divididos aleatoriamente em 2 grupos, nos quais o grupo controle consistia em 96 pacientes tratados com overdenture imediato apoiado por implante mandibular pelo sistema de implante Xive, enquanto o grupo de observação incluiu 96 casos tratados com o sobredentadura pelo sistema de implantes Itália B&B. Os pacientes foram acompanhados por 1 ano e, em seguida, foram comparados os estados de sobredentaduras implanto-suportadas, reabsorção óssea marginal ao redor do osso alveolar, compatibilidade das restaurações do implante com dentes adjacentes, eventos adversos e grau de satisfação. De acordo com os resultados do seguimento de 1 ano, a reabsorção ao redor do osso alveolar do grupo de observação foi significativamente maior que a do grupo controle (p <0,05). No grupo de observação, as diferenças na posição da margem gengival labial, cor gengival e textura foram significativamente melhores (p <0,05) em comparação ao grupo controle. A incidência de eventos adversos foi notavelmente menor (p <0,05). O sistema de implantes B&B da Itália tem um efeito curativo significativo nas sobredentaduras mandibulares suportadas por implantes, com boa compatibilidade das restaurações dos implantes com dentes adjacentes e baixa taxa de incidência de reações adversas, por isso é digno de aplicação clínica e disseminação.

Three-dimensional finite element analysis of mini implants supported mandibular overdentures / 中国组织工程研究

BACKGROUND: Overdenture supported by two to four implants located in the mandibular mental foramen area has been widely used in edentulous patients. However, in patients with severe mandibular resorption, it is a challenging to insert conventional implants. Mini-implants are a better choice in these cases. OBJECTIVE: To compare and analyze the biomechanical characteristics of conventional and mini-implants supported mandibular complete overdenture and to reveal the influence of different implant repair methods on implants and its surrounding tissues. METHODS: The cone beam CT data of a healthy patient scheduled to receive complete edentulous implant supported overdenture was obtained. CT data of the patient, implant and attachment data were imported into the software to create four models: 2 normal implants, 4 normal implants, 4 mini implants, and 5 mini implants supported mandibular overdentures respectively. The overdenture was bilaterally subjected to a vertical load of 150 N. The displacement and stress of implants and the stress of bone were compared. RESULTS AND CONCLUSION: For all models, the lowest and highest maximum values of stress in bone were obtained from 4 normal implant model (2.71 MPa) and 4 mini implant model (7.93 MPa). The lowest and highest maximum values of displacement in implant were obtained from 4 normal implant model (1.37 µm) and 2 normal implant model (1.57 µm). Moreover, the lowest and highest maximum values of stress in implant were demonstrated from 4 normal implant model (12.90 MPa) and 4 mini implant model (22.17 MPa). The biomechanical values of mini implant models were higher than those of conventional models. The biomechanical values of all models were below the critical limits. The distribution was more homogenous and the maximum values of displacement in the implant, stress in implant and stress in bone were reduced as the number of implants increased. Three-dimensional finite element analysis revealed that mandibular overdenture supported by four or five mini implants is a reliable treatment option.

Effects of type of magnet attachment and implant angulation in two implant overdenture models

PURPOSE: The purpose of this study is to evaluate the effects of type of magnet attachment and implant angulation in two implant overdenture models.MATERIALS AND METHODS: Magnet attachments used in this study were flat and dome types (MGT5515, MGT5520D, Dentium Co., Seoul, Korea). Two implants with keepers were inserted in the resin blocks at a distance of 24 mm. For the first model, the implants were parallel to the vertical and perpendicular to the horizontal; for the second model, both were angulated 5 degrees to the mesial; for the third model, both were angulated 10 degrees toward the mesial. The retentive force was measured in both vertical and lateral directions. Statistical analyses were performed using SPSS software version 22.0 (α=.05).RESULTS: The flat type magnet attachment showed the highest lateral retentive force in the 20° divergent group (P<.05) and the dome type magnet attachment showed the highest lateral retentive force in the parallel group (P<.05). The vertical and lateral retentive force of the dome type magnet attachment was greater than that of the flat type magnet attachment in every direction (P<.05).CONCLUSION: Within the limitations of this study, the dome shape magnet attachment can resist vertical and lateral retentive force more superiorly than the flat type magnet attachment, regardless of angle, in the mandibular two implant model.

Comparing different bar materials for mandibular implant-supported overdenture: Finite-element analysis

Aim: This study was conducted aiming to optimize the selection of bar material that can minimize stresses on mandibular bone. Subjects and Methods: One finite-element model was created under ANSYS environment to evaluate the use of different materials as a bar-manufacturing material in mandibular implant-supported overdenture (OD). Model components were created on engineering computer-aided design software and then assembled under the finite-element package. A force of 200 N was unilaterally and vertically applied on the left second premolar area. Results: Within these study conditions, the polyether ether ketone bar produced the lowest Von Mises stress on OD and the maximum value of deformation. Stainless steel bar produced the maximum OD total deformation. Conclusions: Cortical and spongy bones are not sensitive to the bar material. Increasing bar material stiffness increases Von Mises stresses in the bar itself and reduces its total deformation, in what is called overconstrained system.

Telescopic overdenture for oral rehabilitation of partially edentulous patient

A case report describing the rehabilitation of a patient presenting with partially edentulous arches and compromised abutment teeth has been described. The aim of this study was to restore function and esthetics and uplift the psychological status of the patient by fabrication of a fixed removable prosthesis using the existing abutment teeth as telescopic overdenture.

The Employment of CBCT in Assessing Bone Loss around Dental Implants in Patients Receiving Mandibular Implant Supported over dentures

The aim of this study is to evaluate bone loss around implants after delivery of implant supported over dentures using CBCT.This study was performed to evaluate Postoperative bone level around mandibular dental implants using cone beamcomputed tomography (CBCT). The study was conducted on 10 completely edentulous patients that were rehabilitated bycomplete overdentures Patients retained mandibular overdentures by two implants installed in the canine region andretained locator attachments. Standard clinical and laboratory techniques were followed for implant insertion and dentureconstruction for all patients. The implants were divided in two groups. Implants bearing locator attachment with blue nyloninsert (Group I) and implants bearing locator attachment with transparent nylon insert (Group II). The twenty insertedimplants were left undisturbed for three months to achieve osseointegration. The mesial, distal, buccal and lingual bonelevel around the dental implants was evaluated, using the CBCT i-CAT scan with Blue sky Plan® software. Bone level wasobtained at six and twelve months after loading. The CBCT measurements of bone level revealed that there was bone lossaround all aspects of the inserted twenty dental implants