Analysis of the biomechanical behavior of short implants: the photo-elasticity method

The aim of this study was to analyze the stress distribution of short implants supporting single unit or splinted crowns by the photo-elasticity method. Four photo-elastic models were produced: A (3.75×7mm); B (3.75×7mm, 3.75×7mm and 3.75×7mm); C (3.75×10mm, 3.75×7mm and 3.75×7mm); D (3.75×13mm, 3.75×7mm and 3.75×7mm). The prostheses were made with Ni-Cr alloy. A load of 100N in the axial and oblique directions was applied, totaling 380 applications, individually capturing their images in each model. The data were randomized and analyzed qualitatively and quantitatively by 2 examiners. The oblique loading was significantly more damaging. The increase in length was favorable for stress distribution (p<0.05). The splinting was beneficial for the transmission of stresses mainly (p<0.05). The splinting of the crowns, as well as increasing the length of the first implant and axial loading was most beneficial in the stress distribution. Short splinted implants behaved better than single unit implants. Increasing of the length of the first implant significantly improved the stress distribution in all analyzed situations.

Análise da rotação ombro-quadril e co-contração muscular do tronco durante um movimento de rotação axial com manuseio de carga

Pós-graduação em Engenharia Mecânica - FEG

Mensuração da profundidade da porção lateral da fossa mandibular, em imagens radiográficas da ATM, obtidas pela técnica transcraniana, em pacientes com dentição decídua, mista e permanente

The author has verified the average depth of the mandibular fossa, in the X-ray image, using the oblique lateral transcranial technique from the right and left sides samples of each patient, which included a total of 176 patients, 87 male and 89 female. The patients were in following phases: deciduous dentítion (the patients had only deciduous teeth in the oral cavity or, if they had any permanent teeth, they could not be in occlusion), mixed dentition (the patients presented deciduous and permanent in the oral cavity) and permanent dentition (the patients had only permanent teeth in the oral cavity), until the eruption of the permanent third molars, in the region from São José dos Campos. São Paulo. Brazil. The patients were under treatment at the Dental School. UNESP (São Paulo State University). ln order to measure the depth of the mandibular fossa in millimeters an imaginary line was traced on the X-ray image, perpendicular to the other line that served as a reference, which was traced from the botton part of the articular eminence up to the tympanosquamous fissure. After the data were obtained and put in a data sheet, they underwent statistical analysis. The results showed that, in the average, the depth of the mandibular fossa in masculine sex is non-statistically signíficant larger than what was observed in feminíne sex, and the right side is larger than the left side, with significant statistical differences. However, only in permanent dentition, in masculine sex, the depth of the mandibular fossa on the right side is larger than on the left side with significant statistical differences

Implantes dentais curtos: alternativa conservadora na reabilitação bucal

The short dental implants represent an option of previsible treatment, its main indication lives in the possibility of avoiding techniques surgical invasive. The literature in the display that the geometry of the implants is of vital importance, combined with wide diameters and surface treatment, mainly when the bone quality is unfavorable. The mechanical resistance can be enlarged, increasing the number of implants and being used the spliting among them. A rigorous protocol prosthodontist should be following with intention of to avoid oblique loads and to control habits parafuncionais. We aimed at to discuss, through a wide bibliographical revision the short dental implants, their characteristics and indications, giving emphasis to the aspects biomechanic of the same ones. Material and Method: The bases given: Pubmed, ISI and Dentistry Oral Science from 1990 to 2009, were consulted to identify researches related to the length of the dental implants, with emphasis to the considered short and the biomechanics related to the same ones. They were located 568 articles, being selected 69 that gathered the inclusion criteria. Result: Among these 69 selected, 26 articles agreed the evidence level. Conclusion: Inside of the limits of appraised data, it can be concluded that the short implants represent a good treatment alternative, especially for cases with reduced bone bed. However a rigorous indication protocol and use should be followed for warranty of the success of the treatment.

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.

Influência do aumento do comprimento de implantes dentários

The use of implants of greater length may be more favorable for the predictability of dental implants. This statement is relevant, since the cause of failures in dental implants are more related to biomechanical complications. The aim of this study was to evaluate the influence of increase of the length around the entire body of the implant. Six models were created with the presence of only one hexagonal implant (Master Screw connection, Implant Systems, São Paulo, Brazil) of 3.75 mm x 7.0 mm (Model A), 3.75 mm x 8.5 mm (Model B ), 3.75 mm x 10.0 mm (Model C) 3.75 mm x 11.5 mm (Model D) 3.75 mm x 13.0 mm (Model E) 3.75 mm x 15.0 mm (Model F) using the method of photoelasticity. The results were visualized through a qualitative analysis of stresses (number and intensity photoelastic fringes). The model A showed a pattern of less favorable stress distribution, the oblique loading was the most detrimental to the related structures. Conclusion: The increased length allowed for a better distribution of stresses. The oblique loading was more detrimental when compared to axial loading.

Simplificação no tratamento da fratura de ângulo mandibular por meio do acesso intrabucal

Mandibular fractures are the injury most commonly found in the facial bones. They have varied etiology, such as automobile, motorcycle and cycling accidents, physical abuse and falls. The choice of treatment of mandibular fractures most often employed is the reduction and fixation of bone fragments. Regarding fractures involving the mandibular angle, access headgear is the most widely used, in view of the action of masticatory muscles causing greater displacement of fractured stumps. Therefore, the proposal to introduce a conservative approach and facilitated for the treatment of fractures of the mandibular angle, as well as to demystify the contraindication to intraoral approach cases unfavorable fracture displacement, this work is to report a clinical casesurgical mandibular angle fracture, treated by intraoral approach. The fracture was fixed with two plates, one following the external oblique line system (1.5 mm) and a lower system (2.0 mm), with the help of percutaneous trocar. This approach is very promising for these cases, in order to ease the technical as well as by reducing the technical complications of extraoral approach.

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.

Straight and angulated abutments in platform switching: influence of loading on bone stress by three-dimensional finite element analysis

PURPOSE: In view of reports in the literature on the benefits achieved with the use of platform switching, described as the use of an implant with a larger diameter than the abutment diameter, the goal being to prevent the (previously) normal bone loss down to the first thread that occurs around most implants, thus enhancing soft tissue aesthetics and stability and the need for implant inclination due to bone anatomy in some cases, the aim of this study was to evaluate bone stress distribution on peri-implant bone, by using three-dimensional finite element analysis to simulate the influence of implants with different abutment angulations (0 and 15 degrees) in platform switching. METHODS: Four mathematical models of an implant-supported central incisor were created with varying abutment angulations: straight abutment (S1 and S2) and angulated abutment at 15 degrees (A1 and A2), submitted to 2 loading conditions (100 N): S1 and A1-oblique loading (45 degrees) and S2 and A2-axial loading, parallel to the long axis of the implant. Maximum (σmax) and minimum (σmin) principal stress values were obtained for cortical and trabecular bone. RESULTS: Models S1 and A1 showed higher σmax in cortical and trabecular bone when compared with S2 and A2. The highest σmax values (in MPa) in the cortical bone were found in S1 (28.5), followed by A1 (25.7), S2 (11.6), and A2 (5.15). For the trabecular bone, the highest σmax values were found in S1 (7.53), followed by A1 (2.87), S2 (2.85), and A2 (1.47). CONCLUSIONS: Implants with straight abutments generated the highest stress values in bone. In addition, this effect was potentiated when the load was applied obliquely.

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 da angulação do implante e tipo de intermediário na distribuição das tensões

The aim of this study was to evaluate the influence of implant angulation and abutment type (UCLA and Estheticone) on stress distribution in screw-retained implant-supported prostheses through photoelasticity. Three models were fabricated with photoelastic resin PL-2 (Vishay, Micro-Measurements Group, Inc Raleigh, N.C., USA) containing one external hexagon implant with 3.75x10mm (Master screw, Conexão Sistemas de Prótese Ltda., Arujá, São Paulo) with 0°, 17° and 30° degrees and a screw-retained prostheses with UCLA and Estheticone abutments. The assembly was positioned in a circular polariscope; axial and oblique (45° degrees) loads of 100N were applied in fixed points on the occlusal crown surfaces by a universal testing machine. The stress generated was photographed and analyzed qualitatively with appropriate software (Adobe Photoshop®). The results demonstrated the same number of fringes for both abutment types for each angulation, with fringes increasing in the same way. A higher number of fringes were closer in the oblique loading mode. It was concluded that there was no significant difference in stress distribution in prostheses with UCLA and Estheticone abutments. Higher stress concentrations were observed with increased implant angulation. Stress concentration and intensity were higher in the oblique load than in axial load application.

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.

Emprego de ma teriais rest auradores adesivos direto no ângulo incisal de incisivos centrais fra turados

A case report of a patient who presents as chief complaint presence of stained restorations in the anterior teeth. After analysis and discussion of the clinical therapeutic approaches to be adopted, it was observed the presence of type class IV restorations on teeth 11 and 21, due to an oblique coronal fracture in the past. But the patient was not satisfied with the aesthetic result, then where was planned the realization of the removal of the restorations, for subsequently be used direct restorative materials for the correction of form, function and esthetics. The final result showed that the restorations were able to return the form, function and aesthetic dental, thereby evidencing the proven development of restorative dentistry in the solution of aesthetic problems.

Mapeamento geológico-geotécnico pelo método de detalhamento progressivo: aplicação no planejamento e gestão de obras rodoviárias

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A articulação do quadril em uma perspectiva preditora da velocidade de marcha em idosas e como foco de intervenção de duas modalidades terapêuticas: Método Pilates e Haste Vibratória

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)