Bone density and implant stability with advanced platelet-rich fibrin in immediately loaded- implant assisted mandibular overdentures / Densidade óssea e estabilidade dos implantes com fibrina rica em plaquetas avançada em overdentures mandibulares com carga imediata

ABSTRACT Objective: The aim of this study is to determine the effect of Advanced Platelet-Rich Fibrin on bone density and implant stability in immediately loaded- implant-assisted mandibular overdentures (Split-mouth study). Material and Methods: Ten completely edentulous patients received two implants in the mandibular canine region and locator attachments were used to retain immediately loaded- implant mandibular overdentures. Each patient served in two Groups, one Group for each side. One side of the mandible received an implant with topical application of Advanced Platelet-Rich Fibrin in the implant osteotomy site (Group I) and the other site received an implant without application of Advanced platelet-rich fibrin (Group II). Each patient was examined clinically for implant stability using Osstell Mentor device and radiographically by ultra-low dose CT scan to measure bone density around the implant at baseline, three, six months, and one year. Results: There were no statistically significant differences (P>.05) in bone density and implant stability among the studied Groups during one year follow-up period. Conclusion : Advanced Platelet-Rich Fibrin has no effect on bone density and implant stability in immediately loaded implant-assisted mandibular overdenture.(AU)

RESUMO Objetivo: O objetivo deste estudo é determinar o efeito da Fibrina Rica em Plaquetas Avançada na densidade óssea e estabilidade dos implantes em Overdentures mandibulares com carga imediata (estudo de boca dividida). Material e Métodos: Dez pacientes edêntulos foram submetidos à instalação de dois implantes mandibulares na região dos caninos e pilares locator foram utilizados como sistema de retenção para as overdentures mandibulares com carga imediata. Cada paciente participou nos dois grupos, sendo um grupo para cada lado. Um lado da mandíbula recebeu implante com aplicação tópica de Fibrina Rica em Plaquetas Avançada no local do sítio cirúrgico do implante (Grupo I) e o outro local recebeu implante sem aplicação de Fibrina Rica em Plaquetas Avançada (Grupo II). Cada paciente foi examinado clinicamente quanto à estabilidade do implante usando o dispositivo Osstell Mentor e radiograficamente por tomografia computadorizada de ultrabaixa dose para medir a densidade óssea ao redor do implante no início do estudo, três, seis meses e um ano. Resultados: Não houve diferenças estatisticamente significativas (P>0,05) na densidade óssea e na estabilidade do implante entre os grupos estudados durante o período de acompanhamento de um ano. Conclusão: A Fibrina Rica em Plaquetas Avançada não tem efeito na densidade óssea e na estabilidade de implantes em Overdentures mandibulares com carga imediata (AU)

Evaluation of bite force and masticatory performance: complete denture vs mandibular overdenture users

Abstract: This cross-sectional observational study with 24 patients evaluated differences in bite force (BF) and masticatory performance (MP) between conventional complete denture (CCD) and implant mandibular overdenture (IMO) users and the correlation between these variables. The BF test was performed bilaterally with an occlusal force device. During the MP test, patients were asked to chew Optocal particles for 40 cycles. The Shapiro Wilk test was employed to verify the normality of the data, the student t test to identify differences between groups, and Pearson's correlation to investigate interrelationships between variables. A multiple linear regression was subsequently performed via the stepwise method. P values ≤0.05 were considered statistically significant. Unlike IMO users, CCD users presented a significant difference (25.6%) in BF between the dominant and non-dominant chewing side (p=0.04). IMO users presented significantly higher BF (p=0.01) without presenting a dominant side (p=0.38), and also performed significantly better for the following MP parameters: MPX50 values decreased by 27.25% in IMO users (p=0.01), MPB decreased by 48.38% (p=0.01), and ME 5.6 decreased by 53.25% (p=0.02), while ME2.8 increased by 151.57% (p=0.01). The BF and MPX50 in the IMO wearers group were negatively correlated (-0.57; p=0.05); this correlation coefficient was the only parameter included in the multivariate regression model. IMO users have higher BF and better masticatory performance than CCD users, especially in terms of chewed particles size reduction. MP is correlated with a higher BF in IMO users through better particle trituration.

Resumo Este estudo observacional transversal com 24 participantes teve como objetivo avaliar as diferenças na força de mordida (FM) e na PM (performance mastigatória) entre usuários de prótese total convencional (PTC) e de overdenture mandibular (OM) e a correlação entre essas variáveis. O teste de FM foi realizado bilateralmente com um dispositivo de força oclusal. Durante o teste de PM, os pacientes foram solicitados a mastigar uma porção padronizada de Optocal por 40 ciclos mastigatórios. O teste de Shapiro Wilk foi empregado para verificar a normalidade dos dados, o teste T de Student para identificar diferenças entre os grupos e os coeficientes de correlação de Pearson para investigar inter-relações entre variáveis. Uma regressão linear múltipla foi realizada pelo método stepwise. Valores de p≤0,05 foram considerados estatisticamente significantes. Diferentemente dos usuários de OM, os usuários de PTC apresentaram uma diferença significativa (34%) na FM entre o lado dominante e o não dominante (p=0,04). Os usuários de OM apresentaram FM significativamente maior (p=0,01) sem apresentar um lado dominante (p=0,38) e obtiveram PM significativamente melhor nos seguintes parâmetros: os valores de PMX50 diminuíram 27,25% (p=0,01), PMB diminuiu em 48,38% (p=0,01), e EM 5.6 diminuiu 53,25% (p=0,02), enquanto EM2.8 aumentou 151,57% (p=0,01). A FM e PMX50 no grupo de usuários da IMO foram negativamente correlacionados (-0,57;p=0,05); esse coeficiente de correlação foi o único parâmetro incluído no modelo de regressão multivariada. Os usuários da OM possuem maior FM e melhor performance mastigatória do que os usuários de PTC, observados principalmente na redução do tamanho das partículas mastigadas. A PM está correlacionada com um maior FM nos usuários da OM através de uma melhor trituração de partículas.

Overdenture on dental remaining in oncological patients: case report / Overdenture sobre remanescente dental em paciente oncológico: relato de caso

Head and neck cancer occupy the seventh place among the most common neoplasms in the world, with an annual incidence of approximately 640,000 new cases. Radiotherapy treatment has been highlighted, because there is greater tissue preservation, possibility of regression of the disease, decreased tumor volume, prevention of possible tumor recurrences and metastases, and even total cancer cure, but patients undergoing radiotherapy are at high risk of osteoradionecrosis if they perform surgical interventions in the region, such as dental implants and dental extraction, making prosthetic rehabilitation of partially edentulous patients after treating oral cancer something complex and often omitted; although it is a crucial factor in restoring oral function. Thus, the aim of the present study was to describe the planning, treatment and follow-up of a twelve-month prosthetic approach to rehabilitate the lower arch shape and function of a partially edentulous patient undergoing head and neck radiotherapy with a full denture mucus supported and tooth retained. After twelve months of follow-up, it was possible to evidence the functional and aesthetic clinical success, with preserved occlusal pattern, soft and bone tissue around and dental roots. (AU)

O câncer de cabeça e pescoço ocupa o sétimo lugar entre as neoplasias mais comuns do mundo, com uma incidência anual de aproximadamente 640.000 novos casos. O tratamento com radioterapia tem se destacado, pois há maior preservação tecidual, possibilidade de regressão da doença, diminuição do volume tumoral, prevenção de possíveis recorrências e metástases tumorais e até cura total do câncer, mas os pacientes submetidos à radioterapia apresentam alto risco de osteorradionecrose se realizar intervenções cirúrgicas na região, como implantes dentários e extração dentária, fazendo com que a reabilitação protética, de pacientes parcialmente dentados depois de tratar o câncer bucal, algo complexo e frequentemente omitido; embora seja um fator crucial para o reestabelecimento da função oral. Assim, o objetivo do presente estudo foi descrever o planejamento, tratamento e acompanhamento de doze meses de uma abordagem protética para reabilitar forma e função do arco inferior de um paciente parcialmente desdentado, submetido a radioterapia de cabeça e pescoço, com o uso de uma prótese total mucossuportada e dente retida. Após doze meses de acompanhamento, foi possível evidenciar o sucesso clínico funcional e estético, com padrão oclusal, rebordo alveolar e remanescentes dentários preservados (AU)

Immediate small-diameter implants as abutments for an overdenture in the edentulous atrophic mandible: report of immersion endoscopic bone in vivo, and histologic bone-implant evaluation after 6 months of function / Implantes de pequeño diámetro como soporte inmediato de sobredentaduras en hueso alveolar mandibular atrófico: reporte de endoscopía de inmersion in vivo y evaluación histológica a los 6 meses de función

The aim of this report was to endoscopically evaluate bone quality in vivo in the immediate installation of temporary small-diameter implants, and again after 6 months of function, through an attachments system for overdenture, in the atrophic mandible of a patient. We also histologically evaluated bone-implant interaction in these temporary small-diameter implants, once the success of the osseointegration of the submerged implants was guaranteed. A patient received a total of 6 implants in the atrophic mandible, two of which were immediately loaded with a provisional prosthesis, and four were left to heal in a submerged way. Further, an immersion endoscopic evaluation was performed during bone drilling, and this showed a compact bone structure with limited vascularization and predominantly cortical structure.This immediate loading protocol involving an overdenture retained by two small-diameter implants of 2.9 mm in the atrophic mandible proved to be successful after 6 months of loading. Clinical and histologic osseointegration was consistently achieved for both of the retrieved immediately loaded implants. This modality allows the patient to be restored with a stable, functional, and aesthetic prosthesis during the osseointegration period of submerged implants and soft-tissue healing, before the removal of the provisional implants. The histological evaluation of bone-implant contact found that the space between the implant threads closer to the surface was filled with woven bone and lamellar bone, but the tissue in contact with the cervical portion of the implants was compatible with cortical bone organization. Also, the newly formed bone has a regular cell distribution and characteristics of advanced maturation after 6 months of function in the atrophic mandible. Anchored overdentures in 2 to 4 small-diameter implants (2.9 mm) for edentulous patients with severe atrophy of the mandible with cortical bone would be a minimally invasive alternative.

Prótesis completa implanto-asistida II / Implant-supported complete denture II

En este artículo espero poder hacer llegar al lector a la comprensión de la evolución protética implanto-asistida, desde el mejoramiento de la retención otorgada a la prótesis completa inferior (PCI) con solo 2 implantes, hasta la rehabilitación totalmente implanto-asistida en paciente edéntulos. Para lograr este objetivo tan ambicioso tendremos que valernos de varios artículos en diferentes números de revista del AAO. En este artículo continuaremos describiendo las resoluciones protéticas para los siguientes casos: A- Sobredentaduras retenidas sobre dos implantes con Ball Attach. B- Sobredentaduras retenidas por Barras utilizando dos implantes. C- Soluciones protéticas para casos con implantes en mal posición. D- Casos en que se agrega un implante por haber dos implantes en mal posición (AU)

The goal of this article is to show the evolution of implant retained prosthesis driven by enhancements on retention of complete lower jaw prosthesis in edentulous patients. This could be reached by a different array of options, ranging from a simple one such as two implants retaining the lower jaw complete prosthesis, to a complex one completely supported and retained by implants prosthesis. Therefore, to reach such an ambitious goal, it will be necessary to devote several AAO series of journal´s articles to describe all these possibilities. In this paper we will continue describing the four following prosthetic cases: A- Ball Attachment retained Over Denture using two implants. B- Bar retained Over Dentures using two implants. C- Prosthetic solution for cases of misplaced implants. D - Adding a third implant for cases of two misplaced implants (AU)

Implant inclination and horizontal misfit in metallic bar framework of overdentures: analysis by 3d-fea method

Abstract The aim of this study was to evaluate by three-dimensional finite element analysis (3D-FEA) the biomechanics involved in bar-framework system for overdentures. The studied factors were latero-lateral angulation in the right implant (-10, -5, 0, 5 and 10 degrees), and different bar cross-sections (circular, Hader and oval) presenting horizontal misfits (50 or 150 µm) on the opposite implant. Positive angulation (5 and 10 degrees) for implant inclination to mesial position, negative angulation (-5 and -10 degrees) for distal position, and zero degree for parallel implants. The von Mises stresses evaluated the bar, screw and the implant; maximum principal, minimum principal and shear stress analyses evaluated the peri-implant bone tissue. Parallel implants provide lower stress in alveolar bone tissue; mesial inclined bars showed the most negative effect on prosthetic structures and implants. In conclusion, bar cross-section showed no influence on stress distribution for peri-implant bone tissue, and circular bar provided better behavior to the prosthetic system. Higher stress concentration is provided to all system as the misfit increases.

Resumo O objetivo neste estudo foi avaliar por meio do método por elemento finito tridimensional (3D-AEF) a biomecânica envolvida na infraestrutura do sistema barra-clipe para overdentures. Os fatores de estudo foram inclinação mésio-distal entre implantes (-10, -5, 0, 5, 10 graus) e diferentes seções transversais da barra metálica (circular, oval e Hader) com desajuste horizontal (50 e 150 µm). Valores de inclinação positivas (5 e 10 graus) indicam inclinação do implante para mesial e valores negativos (-5 e -10 graus) mostram inclinação para distal, enquanto zero grau indica implantes paralelos. Valores de tensões equivalentes de von Mises foram utilizadas nos sistemas barra, parafuso e implante. Tensão máxima e mínima principal, e cisalhante foram utilizadas para análise do osso alveolar peri-implante. Implantes paralelos promoveram menores tensões em tecido peri-implante; as inclinações para mesial apresentaram piores resultados para as estruturas protéticas e implantes. As diferentes seções transversais da barra não mostraram influência na distribuição de tensões no osso alveolar peri-implante. Concluindo, a barra circular apresentou melhores resultados para os componentes protéticos e maiores valores de tensões foram observados em todos os modelos na medida que o desajuste aumentou.

Clinical outcomes of implant-retained overdentures:A retrospective study / 实用口腔医学杂志

Objective:To evaluate the clinical outcomes of implant-retained overdentures.Methods:57 patients treated by implant-retained overdentures were included.Parameters for peri-implant tissue conditions (e.g.peri-implant probing depth,plaque index,bleeding on probing,mucosal hyperplasia,peri-implant marginal bone loss) and prosthetic complications were examined and recorded.The precentage of satisfaction of the patients was assessed using the visual analog scale (VAS).Results:After an average follow-up of (48±11.3) months,the survival rate of the implants was 98.1%,the marginal bone loss was (1.38±0.74) mm.There was no statistically difference among the different attachment groups(bar,magnet and ball) regarding the peri-implant marginal bone loss or bleeding on probing(P>0.05).The peri-implant probing depth and plaque index in patients with magnet and ball attachments were lower than those in patients with bar attachments(P0.05),except that magnet and ball attachments were much easier to clean compared with bar attachments(P<0.05).Conclusion:Implant-retained overdenture is a successful and satisfactory treatment option for patients with edentulous jaw.The patients should been given regular clinical examinations to keep peri-implant tissue health and reduce the complications,especially those with bar attachments.

Effects of new implant-retained overdentures on masticatory function, satisfaction and quality of life

The aim of this study is to evaluate the effects of replacing poorly fitting dentures on patient’s masticatory function, satisfaction and oral healthrelated quality of life. Fourteen patients with conventional maxillary complete dentures and mandibular overdentures retained by two implants bar clip system had their dentures replaced. The laboratory tests for the analysis of masticatory performance were conducted using an “Optocal” food simulator test. Questionnaires were used to evaluate patient satisfaction with dentures and impact of oral health on quality of life. Tests were conducted and questionnaires were administered before and 1, 3 and 6 months after the patient had adapted to the new dentures. Masticatory performance data and satisfaction with dentures (Visual Analogic Scale) were statistically analyzed by ANOVA and Tukey b test, satisfaction with dentures (SATs P) and impact of oral health on quality of life were evaluated using the Wilcoxon and Friedman tests (a=.05). There was no statistically significant improvement in masticatory function after denture replacement, although better outcomes were observed. Satisfaction with dentures and total score obtained using the OHIPedent showed significant improvement. It can be suggested that the potential for grinding food, patient satisfaction and aspects of quality of life improved immediately after denture replacement.

Avaliar os efeitos da substituição de próteses mal adaptadas na função mastigatória, satisfação e qualidade de vida relacionada à saúde bucal do paciente. Quatorze pacientes com próteses totais convencionais maxilares e overdentures retidas por dois implantes mandibulares sistema barra clip e tiveram suas próteses substituídas .Os testes laboratoriais para análise da performance mastigatória foram realizados utilizando um simulador de alimento “Optocal”. Foram utili za dos questionários para avaliar a satisfação com a prótese eo impacto da saúde bucal na qualidade de vida. Os testes foram realizados e os questionários foram aplicados antes, 1, 3 e 6 meses após o paciente ter adaptado às novas próteses. Os dados da performance mastigatória e satisfação com a prótese (EscalaAnalógica Visual) foram analisados estatistica mente por análise de variância e teste de Tukey b, a satisfação com próteses (SATs P) e o impacto da saúde bucal na qualidade de vida foram avaliados pormeio dos testes de Wilcoxon e Friedman (a = 0,05). Não houve melhora estatisticamente significativa na função mastigatória após a troca das próteses, embora melhores resultados foram observados após a substituição. Satisfação com a prótese e a somatória total obtida utilizando o OHIPEdent mostraram melhora significativa. Pode se sugerir que o potencial de trituração dos alimentos, a satisfação do paciente com as novas próteses e aspectos da qualidade de vida melhoraram imediatamente após a substituição da prótese.

Application of Different Types of Magnet Retention Systems in the Prosthetic Practice.

The magnetic systems as retention units in overdentures are especially used in dental prosthetics designed ​​on the appropriate endodontically treated dental root. With the rapid development of materials and technology their application with overdentures on implants is enabled. In dentistry for a long time magnets made ​​from alloys of aluminium - nickel - cobalt have been used with open field. Their success was limited because these magnets are susceptible to corrosion in contact with saliva and because their retention force is weaker than that retention offered by the mechanical attachments. The preparation of the magnets from alloys of rare earth elements samarium and neodymium enabled greater magnetic force per unit size. Also a new generation of containers allows laser welding with which the protection of the magnetic units from salivary corrosion has been improved. The interest in such attachments is growing which is justified, because the magnets, unlike mechanical attachments have the potential of unlimited duration and may be superior to either mechanical ball or bar attachments in achieving retention for overdentures. Moreover, the magnetic unit provides little resistance to lateral displacement, with which the impact of potentially damaging lateral forces on the retention tooth or implant is reduced.

Effect of abutment angulation in the retention and durability of three overdenture attachment systems: An in vitro study

PURPOSE: This in vitro study investigated and compared the durability and retention of three types of attachments. MATERIALS AND METHODS: Three commercially available attachments were investigated: Clix(R), Dalbo-Plus(R) and Locator(R). In total, 72 samples of these attachments were placed in the acrylic resin forms and subjected to mechanical testing (5400 cycles of insertion and removal) over the respective ball or Locator abutments immersed in artificial saliva at pH 7 and 37degrees C. The abutments were placed at angulations of 0degrees, 10degrees and 20degrees. The retention force was recorded at the beginning and after 540, 1080, 2160, 3240, 4320 and 5400 insertion-removal cycles. RESULTS: The results revealed that there were significant differences in the average values of the insertion/removal force due to angulation (F (2.48) = 343619, P<.05) and the type of attachment (F (7.48) = 23.220, P<.05). CONCLUSION: Greater angulation of the abutments was found to influence the retention capacity of the attachments, and the fatigue test simulating 5 years of denture insertion and removal did not produce wear in the metal abutments.

Strains around distally inclined implants retaining mandibular overdentures with Locator attachments: an in vitro study

PURPOSE: The aim of the present study was to evaluate, by means of strain gauge analysis, the effect of different implant angulations on strains around two implants retaining mandibular overdenture with Locator attachments. MATERIALS AND METHODS: Four duplicate mandibular acrylic models were constructed. Two implants were inserted in the canine regions using the following degrees of distal inclinations: group I (control); 0°, group II; 10°, group III; 20°, and group IV; 30°. Locator pink attachments were used to connect the overdenture to the implants and Locator red (designed for severely angled implants) was used for group IV (group IV(red)). For each group, two linear strain gauges were attached at the mesial and distal surfaces of the acrylic resin around each implant. Peri-implant strain was measured on loading and non-loading sides during bilateral and unilateral loading. RESULTS: For all groups, the mesial surfaces of the implants at loading and non-loading sides experienced compressive (negative) strains, while the distal implant surfaces showed tensile (positive) strains. Group IV showed the highest strain, followed by group III, group II. Both group I and group IV(red) showed the lowest strain. The strain gauges at the mesial surface of the loading side recorded the highest strain, and the distal surface at non-loading side showed the lowest strain. Unilateral loading recorded significantly higher strain than bilateral loading. CONCLUSION: Peri-implant strains around two implants used to retain mandibular overdentures with Locator attachments increase as distal implant inclination increases, except when red nylon inserts were used.

The influence of saliva pH value on the retention and durability of bar-clip attachments

PURPOSE: The aim of this study was to compare the durability and retention of 4 types of attachments placed over computer aided design/computer aided manufacturing (CAD/CAM) titanium bars when subjected to different pH conditions. MATERIALS AND METHODS: Four commercially available attachments were investigated: Hader Yellow, Hader Red, Ackerman Gold and Ackerman Stainless Steel. These attachments and Ackerman CAD/CAM titanium bars were placed in 2 vessels containing different artificial saliva solutions (pH 7/pH 4) at 37degrees C for one month to simulate corrosion conditions, and they were then subjected to mechanical testing (5400 cycles of insertion and removal). RESULTS: The results revealed that there were significant differences in the average values of insertion/removal force due to the pH (F (1, 24)=9.207, P<.05) and the type of attachment (F (3, 24)=11.742, P<.05). CONCLUSION: More acidic pH values were found to have a negative influence on the retention capacity of the attachments.

Implant-supported overdentures with different bar designs: A retrospective evaluation after 5-19 years of clinical function

PURPOSE: This retrospective study evaluated the outcome of implant-retained overdentures (IODs) after 5-19 years of clinical function. MATERIALS AND METHODS: A retrospective analysis of patient files was performed referring to 27 patients who received 36 IODs with 3 different bar designs (group A=prefabricated round bars, n=7; group B=one-piece anterior milled bars, n=20; and group C=two bilaterally placed milled bars, n=9) in the mandible (n=24) and/or in the maxilla (n=12). The analysis focused on the survival and success rates (according to Kaplan-Meier) of the implants and prostheses. Technical complication rates for each type of restoration were analyzed and compared via one-way ANOVA and the Chi-squared test. The prevalence of peri-implantitis (radiographic bone loss > or =3.5 mm) was evaluated by digital analysis of panoramic radiographs taken post-operative (baseline) and after 5-19 years of clinical function (follow-up). RESULTS: The mean observational time was 7.3 years. The survival rates of the prostheses and implants were 100% and 97.7%, respectively. Technical complications occurred more frequently in group A (mean: 3.5 during observational time) than in the other two groups (B: 0.8; C: 1.0). However, this difference was not statistically significant (P=0.58). Peri-implantitis was diagnosed for 12.4% of the implants in 37% of the patients. CONCLUSION: Bar-retained IODs are an adequate treatment option for edentulous jaws. These restorations may exhibit high implant/prosthesis survival rates (>97%), and a limited incidence of technical complications after a mean observational period of >7 years. Nevertheless, peri-implantitis was identified as a frequent and serious biological complication for this type of reconstruction.

Caracterización metalográfica de barras para sobredentaduras, elaboradas por sobrecolado de pilares para implantes dentales / Metallographic characterization of overdenture bars manufactured by overcasting abutments for dental implants

Introducción: la dificultad en el manejo de prótesis totales convencionales en pacientes totalmente edéntulos puede ser mejorada con el uso de sistemas de anclaje sobre implantes dentales para sobredentaduras. El objetivo fue caracterizar metalográficamente un sistema de barras para sobredentadura por sobrecolado de una aleación de metal base, sobre pilares prefabricados en aleación de titanio. Métodos: mediante un diseño de barras para sobredentaduras, elaboradas con un aditamento de titanio (Ti-6Al-4V) prefabricado y una aleación de metal base (Ni65%-Cr22,5%-Mo9,5%). Se hace caracterización metalográfica del proceso de sobrecolado, analizando la influencia en la microestructura de las aleaciones dentales comerciales Ti-6Al-4V y Ni65%-Cr22,5%-Mo9,5% (Wiron 99) mediante microscopía electrónica de barrido (SEM), microanálisis por técnica de espectrometría de energías dispersivas de rayos X (EDS), análisis mediante microscopía óptica (MO) y estereomicroscopía (EM). Resultados: se encontró que durante el proceso de sobrecolado, se produce una unión química con presencia de oxígenos entre estas 2 aleaciones; evidenciando estructuras dendríticas heterogéneas a lo largo de las muestras debido a la irregularidad en el espesor de las barras utilizadas y los precipitados en sus fronteras de Mo. Conclusiones: la unión química de las 2 aleaciones de Ni65%-Cr22,5%-Mo9,5%y Ti-6Al-4V después del proceso de sobrecolado, permite considerar desde el punto de vista metalográfico, el sobrecolado entre estas dos aleaciones como una opción viable para la realización de estructuras sobre pilares de implantes.

Introduction: the difficulty in handling conventional dentures in fully edentulous patients may be improved by using anchorage systems on dental implants for overdentures. The goal of this study was to conduct a metallographic characterization of a system of bars for overdentures by overcasting a metal base alloy on prefabricated titanium alloy abutments. Methods: using a design of overdenture bars, made with an addition of prefabricated titanium (Ti-6Al-4V) and a metal base alloy (Ni65-Cr22%,5%-Mo9,5%), a metallographic characterization of the overcasting process was performed by analyzing its influence on the microstructure of two commercial dental alloys: Ti-6Al-4V and Ni65%-Cr22,5%-Mo9,5% (Wiron 99) using scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), light microscopy analysis (LM), and stereomicroscopy (EM). Results: the findings suggest that during overcasting a chemical bonding occurs due to the presence of oxygen between these two alloys, showing heterogeneous dendritic structures along the samples due to thickness irregularities on the bars and to precipitations of their molybdenum borders. Conclusions: from a metallographic perspective, the chemical bonding of the two alloys (Ni65-Cr22%, 5%-Mo9, 5% and Ti-6Al-4V) after overcasting suggests that overcasting between these two alloys is a viable option for placing structures on implant abutments.

A simplified technique for custom made overdenture semi-precision attachments.

Context: Overdentures are the choice of treatment for most of them, but the only snag is its cost. In India, the rural areas are still deprived of quality treatment. This manuscript is showcasing a study, which is a cheaper, but effective way to provide the best to the patient. Aims: The aim of this study was to develop a custom made system, which can be used as an alternative treatment for the management of patients who need overdentures. The primary objective of this study was to provide a cost-effective attachment with the best functional efficacy. Materials and Methods: The semi-precision attachments were made by using the conventional technique of preparation of post space. The patterns were prepared by using the pattern resin material and the rest of the male and female attachments were fabricated by using innovative methods fulfilling the criteria. Results: The attachments were successfully used in patients with remarkably good function and comfort. Conclusion: It was a successful attempt to provide the specialized treatment in affordable cost. There is a need of innovative work to make the sophisticated systems more economical and readily available.

Sobredentaduras mandibulares inmediatas: revisión de literatura / Immediate mandibular overdentures: review of literature

Las Prótesis totales convencionales aún cuando bien confeccionadas, pueden presentar deficiencias en la retención, estabilidad y soporte, además de la incomodidad y acumulo de alimentos. Las sobredentaduras sobre implantes fueron consideradas una alternativa para solucionar problemas y experiencias negativas con las prótesis convencionales, así también pueden ser una alternativa a los tratamientos complejos (quirúrgico/protésico) con prótesis fijas soportadas por implantes. Buscando reducir el período de cicatrización para la confección de las prótesis, las investigaciones mostraron altos índices de éxito para los tratamientos con sobredentaduras mandibulares inmediatas sobre implantes, que fueron utilizadas en la rehabilitación de pacientes edéntulos. Este trabajo tiene como objetivo abordar, por medio de una revisión de literatura, la viabilidad de la utilización de sobredentaduras mandibulares implanto retenidas. Los implantes de carga inmediata que retienen una sobredentadura mandibular que ha mostrado ser un método reproducible, previsible y de confianza para restablecer una eficiente función masticatoria a los pacientes totalmente edéntulos

Conventional complete denture even though well confectioned, could present deficiencies in the retention, stability and support, in addition uncomfortable and retention of food below it. The overdentures have been considered an alternative to resolve problems and negative experiences with the conventional dentures, thus also can be an alternative to the complex treatments (surgical/prosthetic) with implant-supported prosthesis. In the attempt to reduce the healing time for the confection of the dentures showed higher rates of success to the implants when immediate mandibular overdentures were used in the rehabilitation of edentulous patients. The aim of this paper was to discuss by means of a Literature review, the viability of the use of mandibular implant-supported overdentures. The immediate mandibular overdentures have been showed like a reproducible method, predictable and confidence to provide an efficient function to the total edentulous patients

Prosthodontic Rehabilitation of A Patient With Dentinogenesis Imperfecta.

Dentinogenesis Imperfecta is an autosomal dominant disorder of tooth development characterized by the presence of opalescent dentin, resulting in a dusky blue to brownish discoloration of the teeth. This condition is genetically and clinically heterogeneous, it may affect only the teeth or it may be associated with the Osteogenesis Imperfecta. It is inherited as autosomal dominant trait and in fact it is one of the most common dominantly inherited disorder in humans. The scalloping at the dentinoenamel junction is thought to help by mechanically interlocking the two hard tissues together. This locking is defective in these conditions which lead to enamel fracture easily from the defective dentin. The exposed dentin may then undergo severe and rapid attrition. Early diagnosis and proper treatment is mandatory in these conditions. Delay in the treatment can cause partial or complete loss of clinical crowns with healthy roots. A case report is discussed in which a young patient with Dentinogenesis Imperfecta was treated with maxillary fixed partial dentures and mandibular fibre reinforced overdentures with metal occlusal surfaces.

Overdentures sobreimplante à barra: aspectos biomecânicos / Bar-clip implant-retained overdentures: biomechanical aspects

As overdentures sobreimplantes apresentam comprovado índice de sucesso por estudos clínicos longitudinais. Porém, há controvérsias na literatura sobre o mecanismo de transmissão e distribuição das tensões decorrentes da função mastigatória sobre overdentures através dos sistemas de retenção e implantes aos tecidos ósseos e de suporte. Assim, ainda nos dias de hoje, os mecanismos responsáveis pelas falhas biomecânicas dos implantes não estão completamente definidos pela literatura e a influência dos diversos fatores biomecânicos não é conclusiva. O objetivo deste estudo foi realizar uma revisão da literatura sobre os aspectos biomecânicos que podem induzir a falhas das overdentures sobreimplante, enfatizando os trabalhos que avaliaram os sistemas de retenção do tipo barra-clipe. Baseado nos estudos até então realizados, pode-se relacionar o uso de implantes esplintados por meio de barras metálicas (sistema rígido) a uma maior concentração de tensão nos implantes e componentes protéticos e, simultaneamente, alívio das tensões nos tecidos de suporte adjacentes aos implantes quando comparado a implantes não-esplintados (sistemas esféricos e magnetos). Porém, as características clínicas de cada paciente devem ser consideradas no planejamento para que ocorra um correto comportamento biomecânico das overdentures sobreimplante, refletindo-se na longevidade do tratamento.

Implant-supported overdentures show high success according to longitudinal clinical studies. However, there are controversies in the scientific literature regarding stress transmission and distribution on the supporting tissues given by retention mechanisms and implants during masticatory function. Nowadays, the mechanisms responsible for biomechanical failures on implants are not well-defined and their influence is inconclusive. The aim of this study was to make a literature review about the biomechanical aspects related to failures in implant-supported overdentures, emphasizing the studies with bar-connecting devices. Based on the reviewed studies, the use of implants connected by metallic bars (rigid system) can be related to a higher stress concentration on the implants and prosthetic components and with a lower stress in the supporting tissues near to the implants compared to non-splinted implants (spherical and magnetic systems). However, the clinical characteristics of each patient must be considered in the treatment planning for adequate biomechanical behavior of implant-supported overdentures, allowing excellent treatment longevity.

Overdenture mandibular com carga imediata em implantes de corpo único / Mandible overdenture with immediate loading in one-piece dental implants

Um dos problemas odontológicos mais evidentes no tratamento reabilitador com prótese total em pacientes edêntulos é a falta de retenção e estabilidade. O presente trabalho tem como objetivo apresentar uma alternativa na reabilitação para pacientes edêntulos com uma overdenture mandibular em implantes de corpo único.

One of the most common problems in the rehabilitation of totally edentulous patients is the difficulty in obtaining retention and stability. The aim of this present work is to present a treatment possibility with a mandibular overdenture in implants of with one-piece dental implants.

Nutritional and anthropometric analysis of edentulous patients wearing implant overdentures or conventional dentures

As masticatory efficiency diminishes drastically in edentulous patients, several researchers have studied over the past two decades how dietary intake varies when different types of oral rehabilitation are provided. Since the use of implants to support prostheses in edentulous mandibles has been shown to significantly improve masticatory performance, the question remains as to whether this improvement will influence the nutritional status. The purose of this study was to evaluate the nutritional status of edentulous patients who randomly received either a mandibular conventional denture (CD) or an implant-supported overdenture (IP) 1 year previously. Weight, height, body composition and handgrip strength measurements were collected for analysis. Blood tests were performed to measure plasma parameters of diet intake. Participants responded to a Food Frequency Questionnaire and a Masticatory Function Questionnaire. Fifty-three people participated (58 percent men, 42 percent women; mean age = 53). Body composition indicators as well as plasma parameters were generally within normal range, and no statistically significant difference (p>0.05) was found between the groups. Patients in the CD group had significantly lower ratings for items regarding difficulty in chewing (p<0.05), but no significant difference was found for dietary intake (p>0.05). Although the CD wearers reported having more difficulty in chewing hard foods, both groups appeared to have a similar nutritional status.

O uso de implantes para suportar próteses em pacientes edêntulos completos causa uma melhora significativa na performance mastigatória desses indivíduos. Contudo, a influência desse benefício no estado nutricional do paciente ainda não está completamente estabelecida. Esse estudo avaliou o estado nutricional de pacientes desdentados completos reabilitados com próteses totais convencionais (grupo CD) ou com próteses totais implanto-suportadas (grupo IP) na mandíbula. Foram coletados dados sobre composição corporal e uma amostra de sangue para análise. Os participantes responderam a um questionário sobre freqüência alimentar (QFA) e outro sobre habilidade mastigatória e método de preparo dos alimentos (QMF). A amostra foi composta de 53 participantes selecionados a partir de um estudo randomizado, sendo 58 por cento homens e 42 por cento mulheres, com idade média de 53 anos. Os indicadores de composição corporal se encontraram dentro da normalidade e sem diferenças significativas (p>0.05). O grupo CD obteve valores significativamente diferentes para itens do QMF sobre dificuldade de mastigar (p<0.05). Os dados do QFA e o resultado do exame de plasma estavam dentro dos níveis normais, e os valores entre os grupos foram semelhantes (p>0.05). Embora os participantes que receberam prótese total convencional tenham relatado maior dificuldade de mastigar alimentos duros, os dois grupos apresentaram estados nutricionais semelhantes.