Implantes curtos do tipo cone-Morse: proporção coroa-implante

The purpose of this study was to analyze the biomechanical interactions in bone tissue between short implants and implant-supported crowns with different heights. Two models were made using the programs InVesalius 3.0, Rhinoceros 4.0 and Solidworks 2010. The models were established from a bone block with the short implant (3.75 x 8.5 mm) with geometry Morse taper connection (MT). The height of the crown (cemented) was set at 10.0 mm and 15.00 mm. The models were processed by programs and 10 NEiNastran Femap 10.0. The force applied was 200N (vertical) and 100N (oblique). The results were plotted on maps Voltage Maximum Principal. Statistical analysis was performed using ANOVA. The results showed that the increase in crown height, increased stress concentration in the crown of 15 mm under oblique loading (p <0.001), the oblique loading has significantly expanded the area of stress concentration (p <0.001). Conclusion:the increase of the crown increased the stress concentration, being statistically significant for short implants Morse taper. The mesial and distal region had the highest concentration of stresses under oblique loading. The oblique loading was more harmful when compared with axial loading, being statistically significant.

Reabilitação Oral: prótese livre de metal, Removível e implantes. Um caso de 12 anos de acompanhamento

The literature has suggested that the association of removable partial dentures with dental implants can improve the quality of life of patients. Thus, the purpose of this study was to present a case report. This case report describes the development of a removable partial denture associated with dental implants bilaterally been monitored for 12 years, and the efficacy of the proposed treatment. The radiographic controls demonstrated no changes on bone tissue. The maxillary arch was rehabilitated with metal-free crowns. The patient was fully satisfied with this technique providing stability, esthetics, and proper function. It was concluded that the technique of using removable partial dentures associated with dental implants is viable and show the advantages of improved function, aesthetics and cost reductions in rehabilitation treatment.

Análise Biomecânica em implantes com diferentes tipos de conexão: estudo pelo MEF-3D

The aim of this study was to evaluate the biomechanical behavior of different implant connection types, by means of three-dimensional finite element analysis. 3 Three-dimensional models were created with a graphic modeling software: SolidWorks 2006 and Rhinoceros 4.0, and InVesalius (CTI, São Paulo, Brasil), the bone was obtained by computerized tomography of a sagittal section of the molar region. The model was composed by bone block with an implant (4 x 10 mm) (Conexão Sistemas de Prótese, São Paulo), with different implant connections: external hex, internal hex and Morse-taper with the corresponding prosthetic component Ucla or Morse-taper abutment. The Three-dimensional models were transferred to finite element software Femap 10.0 (Siemens PLM Software Inc., CA, USA), to generate a mesh, boundary conditions and loading. An axial (200N) and oblique load (100N) was applied on the occlusal surface of the crowns. Analyses were performed using the finite element software NEiNastran 9.0 (Noran Engineering, Inc., USA) and transferred to the Femap 10.0 to obtain the results; after the results were visualized using von Mises stress maps and Maximum stress principal. The results showed the stress distribution was similar between models, with a little superiority of Morse-taper connection. It was concluded that: the three connection types were biomechanical viable; The Morse-taper connection presented the better internal stress distribution; there was not significant biomechanical differences on the bone.

Comportamento biomecânico dos sistemas de retenção de overdentures

Objective: to the purpose of this study was to compare the stress distribution in the peri-implant hard tissue on different attachment systems for mandibular or maxillary implant-retained overdentures. Material and methods: the search for published studies was performed on PubMed/Medline database covering the period of January 2000 to April 2014. The selection of the eligible studies was performed according to including and excluding criteria. Results: a total of 140 studies were screened and according to the search strategy, 21 studies were selected for this review. Eight studies perfomed strain-gauge analysis, 5 evaluated the stress distribution though photoelastic test and 7 performed tridimensional finite element analysis. Only one study in vivo was included. Non-splinted O-rings showed better stress distribution than other bar-clip attachment systems. Conclusions: the present study did not find sufficient evidences regarding the most indicated attachment system for overdentures with better stress distribution for the peri-implant hard tissue. The methodologies analyzed should be complemented with other tests and used as a tool for further clinical studies.

Solução estética para prótese sobre implante

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. No entanto, em alguns casos, isso não ocorre principalmente pela grande reabsorção tecidual na região, na qual deveria ter sido realizado enxerto ósseo, antes mesmo da instalação dos implantes. Desse modo, o objetivo deste trabalho foi apresentar uma solução reabilitadora estética para essas possíveis falhas durante o planejamento com reabilitações sobre implantes, por meio de gengiva artificial cerâmica.

Influência do material oclusal na distribuição de tensões em próteses implantossuportadas unitárias

Objective: the aim of this study was to evaluate the influence of occlusal veneering material in single fixed implant-supported crowns through the 3-D finite element method. Material and methods: Four models were fabricated using the Rhinoceros 4.0, SolidWorks, and InVesalius softwares. Each model represented a block of mandibular bone with an external hexagon implant of 5 mm x 10 mm and different veneering materials including NiCr (1), porcelain (2), composite resin (3), and acrylic resin (4). An axial load of 200 N and an oblique load of 100 N were applied. Results: model (2) with porcelain veneering presented a lower stress concentration for the NiCr framework, followed by the composite resin and acrylic resin. The stress distribution to the implant and bone tissue was similar for all models. Conclusions: there is no difference of stress distribution to the implant and supporting structures by varying the veneering material of a single implant-supported prosthesis.

Influência do material oclusal na distribuição de tensões em próteses implantossuportadas unitárias

Objective: the aim of this study was to evaluate the influence of occlusal veneering material in single fixed implant-supported crowns through the 3-D finite element method. Material and methods: Four models were fabricated using the Rhinoceros 4.0, SolidWorks, and InVesalius softwares. Each model represented a block of mandibular bone with an external hexagon implant of 5 mm x 10 mm and different veneering materials including NiCr (1), porcelain (2), composite resin (3), and acrylic resin (4). An axial load of 200 N and an oblique load of 100 N were applied. Results: model (2) with porcelain veneering presented a lower stress concentration for the NiCr framework, followed by the composite resin and acrylic resin. The stress distribution to the implant and bone tissue was similar for all models. Conclusions: there is no difference of stress distribution to the implant and supporting structures by varying the veneering material of a single implant-supported prosthesis.

O impacto das próteses implantosuportadas na harmonia facial

Many patients seeking dental care wish to improve facial and smile aesthetics to be accepted in modern day society. In denture wearers, the physiological resorption causes atrophy mainly in the maxilla, being necessary to carry out reconstruction techniques and sometimes orthognathic surgery to improve occlusal stability and facial harmony. The aim of this study is to discuss the features related to the rehabilitation of edentulous patients with indication for reconstruction of the maxilla using bone grafts and orthognathic surgery by means of a clinical case. In the present case, after the prosthetic rehabilitation, the patient was full satisfied with obtained results and dismissed the initially proposed surgical protocol. Therefore, professionals should provide therapeutic options but the patient’s opinion should prevail provided its clinical feasibility.

Wettability behavior of nanotubular TiO2 intended for biomedical applications

Nanotubes have been subject of studies with regard to their ability to promote differentiation of several cells lines. Nanotubes have been used to increase the roughness of the implant surfaces and to improve bone tissue integration on dental implant. In this study TiO2 nanotube layer prepared by anodic oxidation was evaluated. Nanotube formation was carried out using Glycerol-H2O DI(50-50 v/v)+NH4F(0,5 a 1,5% and 10-30V) for 1-3 hours at 37ºC. After nanostructure formation the topography of surface was observed using field-emission-scanning-microscope (FE-SEM). Contact angle was evaluated on the anodized and non-anodized surfaces using a water contact angle goniometer in sessile drop mode with 5 μL drops. In the case of nanotube formation and no treatment surface were presented 39,1° and 75,9°, respectively. The contact angle describing the wettability of the surface is enhanced, more hydrophilic, on the nanotube surfaces, which can be advantageous for enhancing protein adsorption and cell adhesion.

Tratamento de superfície de implantes dentários: SBF

Various surface treatments of dental implants have been developed in order to ensure anchorage to bone tissue, optimization of the determinants of electronic structure, crystallinity, composition and properties. Coating techniques have been proposed in order tocreate unionbiochemicalable to accelerate the early stages ofbone tissue, combining the positive properties of titanium and its alloys bioactivity of ceramic materials. This paper discusses protocol for handling the SBF coating of titanium alloys. The apatite phase nucleation occurs by immersing the substrate in synthetic solution simulating blood plasma (Simulated Body Fluid). The protocol allows manipulation of the SBF solution to establish guidelines regarding the usestreamlinedand organized to make practical application.

Odontological assistance to Down Syndrome patients having congenital heart malformations

In this study the authors present the frequency and types of congenital heart malformations (CHM) among Down Syndrome (DS) patients emphasizing the prevention of infectious endocarditis (IE) with appropriate antibiotic prophylaxis (ABP). Out of 390 DS patients, 312 (80%) were considered free from any CHM. 78 (20%) presented some CHM; from these 11,54% (n=9) have more than one CHM; ABP to prevent IE was recommended for 41,03% (n=32). Ventricular septal defect was the most frequent CHM (20,51%, n=16). Dentists must know about the patients’ cardiologic diagnosis before a treatment that could cause bleeding, because they have to administer antibiotics to prevent IE. Although some CHM doesn’t need ABP, according to the protocol of the American Heart Association, there are systemic conditions in DS that are relevant to the prescription of antibiotics.

Influência da menopausa no tratamento endodôntico

A menopausa é uma das mudanças fisiológicas caracterizadas pelo encerramento dos ciclos menstrual e ovulatório, ocorrendo nas mulheres entre a quarta e a quinta década de vida. Com ela, ocorre uma diminuição na produção de estrógeno, um importante hormônio que atua em muitos processos fisiológicos do indivíduo, como a regulação do sistema esquelético. O declínio nos níveis de estrógeno resulta em perda de densidade mineral óssea, aumento do risco de fratura, bem como no aparecimento de doenças ósseas, como a osteoporose, um processo patológico onde há o aumento na reabsorção de cavidades que não são completamente preenchidas por osso neoformado. Além disso, a deficiência de estrógeno pode causar muitas mudanças na saúde bucal do indivíduo. Na presença de uma infecção bacteriana no tecido pulpar, essa deficiência pode agravar a periodontite apical. Vários medicamentos têm sido estudados como potenciais agentes terapêuticos para suprir a deficiência de estrógeno. Essas drogas têm como objetivo reduzir o risco de fraturas e prevenir a perda óssea e distúrbios cardiovasculares e mentais resultantes de deficiência hormonal pós-menopausa. O raloxifeno (RLX), é uma das drogas terapêuticas mais estudadas, demonstrando prevenir a perda óssea. Mesmo com a indicação e benefícios do raloxifeno no metabolismo ósseo e na manutenção da densidade óssea, estudos sobre o seu papel na infecção endodôntica em organismos osteopênicos precisam ser realizados.

Osteotomia com brocas de alta e baixa rotação, com e sem refrigeração líquida: estudo histopatológico duplo cego em suínos

Nine swines of the White Large race were used for study of the process of bony repair after osteotomy with rotating instruments of low and high-speed, with and without liquid refrigeration. The authors observed, through double blind histopathological analysis, that in every analyzed operative time, the bony repair was processed more appropriately when the osteotomies were accomplished with liquid refrigeration. In the final postoperative times, of fourteen and twenty-eight days, the best results of bony repair were observed in the osteotomy accomplished with drills of low rotation and with liquid refrigeration, while in the postoperative time of seven days, the results of the bony repair of osteotomy accomplished with drills of high rotation and with liquid refrigeration they were better. The authors consider, still, that the process of bony repair in swine display larger proximity in the histological pictures among the studied variables, when compared with other biological models. As most of the works told in the literature it refers the use of dogs, the authors consider that the present work guarantees your importance in the sense of looking for a closer model of the man.

Lesão fibro-óssea na mandíbula associada à osteomielite

A displasia cemento-óssea é o tipo mais comum dentre as lesões fibro-ósseas, podendo apresentar-se de 3 maneiras: periapical, focal e florida. Paciente parda, de 53 anos, compareceu com queixa de “secreção na gengiva” e histórico de exodontia na região há 8 meses. À inspeção apresentou uma leve tumefação na região vestibular posterior esquerda da mandíbula e uma pequena fístula drenando pus. Realizou-se uma radiografia panorâmica, que revelou uma lesão de radiopacidade mista na região de molares inferiores direitos, medindo 2 cm de diâmetro; outra lesão radiopaca na região de pré-molares esquerdos, de 6mm de diâmetro - ambas bem delimitadas; e outra área radiolúcida com radiopacidade central, com halo radiopaco na região infectada, medindo 1,5 cm de diâmetro. O diagnóstico presuntivo foi de displasia cemento-óssea infectada, cisto periapical infectado associado à displasia e osteomielite. Após antibioticoterapia, realizou-se biópsia e curetagem da área. Microscopicamente apresentou áreas de tecido cemento-ósseo em forma trabecular e no local onde deveria haver tecido fibroso, presença de biofilme bacteriano, conteúdo hemorrágico e restos necróticos. No tecido de granulação removido observou-se intenso infiltrado inflamatório e áreas de calcificação cementóide. As características microscópicas juntamente com os achados clínicos e radiográficos levaram ao diagnóstico de osteomielite aguda supurativa secundária a lesão fibro-óssea, sugestiva de displasia cemento-óssea florida.

Anestesia peridural com lidocaína em um potro: relato de caso

Um equino macho, raça Manga Larga, de 20 dias de idade, pesando 55 kg foi atendido no Hospital Veterinário “Luiz Quintiliano de Oliveira” com histórico de queda no dia anterior, apresentando impotência funcional e desvio do eixo ósseo do membro pélvico esquerdo (MPE). Ao exame radiográfico, constatou-se uma fratura classificada como Salter- Harris tipo II, na região distal da tíbia esquerda, com indicação para osteossíntese. Ao exame físico geral, observou-se frequência cardíaca (FC) de 82 batimentos.min-1, frequência respiratória (f) de 60 movimentos.min-1, mucosas róseas, tempo de preenchimento capilar de dois segundos, temperatura retal (ToC) de 38,5oC e hidratação adequada. Como medicação pré-anestésica, administrou-se xilazina (0,5 mg.kg-1) IV. A indução foi realizada por meio da administração de midazolam (0,1mg.kg-1) e cetamina (2mg.kg-1) IV. Seguiu-se a intubação orotraqueal com sonda n o 12 conectando-se a um circuito anestésico com reinalação parcial de gases, e a manutenção foi realizada com isofluorano em fluxo diluente de oxigênio a 100%, sob ventilação espontânea. Realizou-se a técnica de anestesia peridural com o paciente em decúbito lateral direito, introduzindo uma agulha 30x8 percutaneamente até atingir o espaço peridural entre as vértebras L6 e S1, onde se administrou lidocaína a 2% (2,2mg.kg-1) com vasoconstritor, perfazendo um volume de 6 mLs. Adicionalmente foi realizado o bloqueio perineural dos nervos tibial e fibular do membro acometido, com administração de 5 mLs de lidocaína a 2% com vasoconstritor em cada ponto. A administração de anestésicos locais pela via peridural na região L6 – S1 não é rotineiramente usada em equinos, uma vez que provoca ataxia ou perda do tônus muscular, aumentando os riscos relacionados à intervenção anestésica. No entanto, a recuperação do potro nesse relato de caso foi rápida e isenta de complicações, provalvelmente proporcionando anestesia multimodal e consequentemente menor depressão cardiovascular. A associação da anestesia peridural e bloqueio dos nervos tibial e fibular à anestesia geral, pode ser uma alternativa para intervenções cirúrgicas em membros pélvicos de potros, uma vez que demonstrou ser efetiva e de fácil execução.