Influência do formato do rebordo alveolar sagital em reabilitações com associação de prótese parcial removível de extremidade livre e implante ósseo integrado

The association of mandibular distal extension removable partial dentures with an osteointegrated implant is a treatment option at hasn't been fully explored by modern rehabilitation dentistry yet. The objective of this study is to evaluate, by means of the bidimensional method of finite elements, the distribution of tension on the structures supporting the distal extension removable partial denture (DERPD), associated to a 10.0 x 3.75 mm osteointegrated implant with an ERA retention system, in alveolar ridges of different shapes. Eight models were created, representing, from a sagittal perspective: Model A (MA) – a half arch with a horizontal ridge without posterior support, with the presence of the lower left canine, and a conventional DERPD, with metallic support in the incisal aspect of this canine, as replacement for the first and second pre-molars and the first and second molars of the lower left half arch; Model B (MB) – similar to MA, but different because of the presence of a 3.75 x 10.00 mm implant with an associated ERA retention system in the posterior region of the DERPD base; Model C (MC) - similar to MA, however with a distally ascending ridge format; Model D (MD) – similar to MC, but different because there is an implant associated to a retention system; Model E (ME) - similar to MA, however with a distally descending ridge format; Model F (MF) – similar to ME, but ditfferent in the sense that there is an implant with an associated ERA retention system; Model G (MG) – similar to MA, however with a distally descending-ascending ridge format; Model H (MH) – similar to MG, but different in the sense that there is an implant with an associated ERA retention system. The finite element program ANSYS 9.0 was used to load the models with vertical forces of 50 N, on each cuspid tip. The format of distal descending edge (ME and MF) was that presented worse results, so in the models with conventional RPD as in the models with RPD associated to the implant and ERA system of retention, for the structures gingival mucosa and tooth support. 1) the distally descending ridge presented the most significant stress in the model with the conventional RPD (ME) or with a prosthesis associated to an implant (MF) and 2) the horizontal ridge (MB) provided more relief to the support structures, such as the tooth and the spongy bone, when there was an implant associated to an ERA retention system. The incorporation of the implants with the ERA system retention, in the posterior area of the toothless edge, it promotes larger stability and retention to PPREL, improving the patient's masticatory acting and, consequently, its comfort and function.

The influence of the alveolar ridge shape on the stress distribution in a free-end saddle removable partial denture supported by implant

The alveolar ridge shape plays an important role in predicting the demand on the support tooth and alveolar bone in the removable partial denture (RPD) treatment. However, these data are unclear when the RPD is associated with implants. This study evaluated the influence of the alveolar ridge shape on the stress distribution of a free-end saddle RPD partially supported by implant using 2-dimensioanl finite element analysis (FEA). Four mathematical models (M) of a mandibular hemiarch simulating various alveolar ridge shapes (1-distal desceding, 2- concave, 3-horizontal and 4-distal ascending) were built. Tooth 33 was placed as the abutment. Two RPDs, one supported by tooth and fibromucosa (MB) and other one supported by tooth and implant (MC) were simulated. MA was the control (no RPD). The load (50N) were applied simultaneously on each cusp. Appropriate boundary conditions were assigned on the border of alveolar bone. Ansys 10.0 software was used to calculate the stress fields and the von Mises equivalent stress criteria (σvM) was applied to analyze the results. The distal ascending shape showed the highest σvM for cortical and medullar bone. The alveolar ridge shape had little effect on changing the σvM based on the same prosthesis, mainly around the abutment tooth.

Influencia del nivel de inserción ósea del diente soporte en el desplazamiento de PPR de extremidad libre mandibular asociada al implante oseointegrado

The rehabilitation with mandibular distal extension removable partial dentures (DERPD) is complex and the use of implants has been improving the functioning of this approach. The insertion bony level around of the last support tooth is an aggravating factor, since it can harm the longevity of the treatment. Thus, the aim of this research was to evaluate the displacement tendency of a mandibular DERPD associated to an implant, with different insertion bony levels and different connections between the RPD and the support tooth, by finite element analysis. Eight models were made: MA - DERPD, incisal rest, no bony loss; MB - DERPD, distal plate, no bony loss; MC - DERPD, incisal rest, no bony loss, with implant and ERA system; MD - DERPD, distal plate, no bony loss, with implant and ERA system; ME - DERPD, incisal rest, bony loss; MF - DERPD, distal plate, bony loss; MG - DERPD, incisal rest, bony loss, with implant and ERA system; MH - DERPD, distal plate, bony loss, with implant and ERA system. Loads of 50 N in each peak were applied. Displacement maps were obtained and showed that implant favors this association and the bony loss harms the prognostic of the prosthesis. It is concluded that: the introduction of the implant with ERA system reduced the displacement tendency of the tooth and supporting structures; introduction of distal plate reduced the movement tendency of the support tooth; the decrease of the periodontal support didn't influence significantly the displacement tendency of the models with distal plate distal, but it influenced the models with distal incisal rest.

Reação de tecido subcutâneo ao cimento Portland modificado (CPM)

Introdução: o objetivo do estudo foi avaliar a resposta do tecido subcutâneo de ratos a implantes de tubos de polietileno com cimento Portland modificado (CPM) (EGEO S.R.L., Buenos Aires, Argentina) comparado com o MTA Angelus® (Angelus, Londrina/PR). Métodos: esses materiais foram colocados em tubos de polietileno e implantados no tecido conjuntivo dorsal de ratos Wistar por 7, 15, 30, 60 e 90 dias. Os espécimes foram preparados e corados com hematoxilina e eosina ou Von Kossa, ou não corados por luz polarizada. Foram realizadas avaliações quantitativas e qualitativas das reações. Resultados: ambos os materiais causaram reações moderadas em 7 dias, decaindo com o tempo. O MTA Angelus causou reações leves em 15 dias, decaindo com o tempo. A resposta foi similar ao controle em 30, 60 e 90 dias com CPM e MTA Angelus. Foram observadas mineralização e granulações birrefringentes à luz polarizada em ambos os materiais. Conclusões: foi possível concluir que o CPM e o MTA Angelus foram biocompatíveis em modelo de rato e estimularam a mineralização.

Achados incidentais de calcificações em tecidos moles: relato de caso clínico

As ossificações do complexo estilo-hióideo (OCEH), os tonsilólitos e os ateromas são exemplos calcificações em tecidos moles incidentalmente encontrados em exames de imagem. Atualmente com a utilização da tomografia computadorizada de feixe cônico (TCFC) na odontologia, há um aumento do número desses achados. Objetivo: Relatar um caso clínico com calcificações em tecidos moles e comparar esses achados entre a radiografia panorâmica e a TCFC do mesmo paciente. Paciente masculino, 77 anos, compareceu a Clínica de Radiologia para realizar radiografia panorâmica e TCFC para planejamento de implantes. Na radiografia panorâmica pode-se observar a OCEH bilateral e presença de uma área radiopaca localizada no ramo ascendente da mandíbula, que foi compatível com esclerose óssea. Na análise da TCFC constatou a presença da OCEH bilateralmente. Porém a área radiopaca primeiramente sugestiva de esclerose óssea, na TCFC foi sugerida como tonsilólito, pois não estava localizada no ramo ascendente da mandíbula, e sim nos tecidos moles da região próxima aos espaços aéreos. No exame de TCFC foi possível a visualização de outra estrutura calcificada do lado direito do paciente, na altura da vértebra C4, heterogênea que foi compatível com ateroma. O diagnóstico das calcificações pode não ser preciso quando se utiliza apenas a radiografia panorâmica, além da possibilidade de apresentar falso negativo, como no caso do ateroma. Assim sendo quando o paciente possuir o exame de TCFC esse deve ser completamente avaliado, para que sejam diagnosticadas as possíveis calcificações em tecidos moles presentes.

Avaliação in vitro de superfícies de titânio irradiadas com laser de Er,Cr:YSGG

Introduction: As a new alternative in the complementary treatment lasers teem different systems were employed in the decontamination of dental surfaces implants however, some systems have caused significant changes in its surface. Purpose: Analyze by Scanning Electron Microscopy (SEM) the effects of laser irradiation of Er,Cr: YSGG on different surfaces of titanium. Material and method: Study of 20 titanium discs, and 10 Machined Surface (MS) and 10 surfaces treated with acid (AC). The 10 discs with the same treatment were divided into two groups with five units each, the irradiation was performed in powers of 1 W and 2 W. Result: Showed that the irradiation with 1 W of power resulted in no significant morphological changes in the MS-irradiated compared to non-irradiated surfaces. In MS surfaces, minor changes were observed in the increase of 1000× when compared to non-irradiated surface. With 2 W of power, there were no significant morphological changes in the MS, compared to non-irradiated areas. In AC some changes were observed in the increase of X 1000, showing areas of wear suggestive of treatment and some areas with melting point. Conclusion: Considering the results and the parameters used in this study it was concluded that the Er, Cr: YSGG irradiation can be used for the machined surfaces of implants, but in acid-treated surfaces irradiation parameters should be more controlled.

Reconstrução de maxila severamente atrófica via enxerto ósseo autógeno de calota craniana: descrição de técnica

Bone reconstructions are traditionally conducted with autogenous grafts harvested from intra- or extra-oral donor sites to reestablish the lost bone volume for further implant-prosthetic rehabilitation. The calvarial bone has been studied as an excellent donor site in large atrophic situations, presenting low resorption rates, as well as complications and minimal morbidity. The hospitalization time is short, with low pain levels, short functional limitations, and invisible scars. The skull microarchitecture is predominantly cortical in the presence of growth factors that demonstrate their osteogenic, osteoinductive, and osteoconductive abilities resulting in low resorption rate and high predictability when compared to the iliac crest. Dural lacerations, extra and subdural bleeding, cerebrospinal fluid leakage, and brain damage have been minimized due to the development of surgical technique. The delimitation of diploe, preserving the internal skull cortex before osteotomy at the donor made it possible to reduce accidents and complications. The aim of this paper is to show a technical and to discuss aspects of the use of calvarial bone in the reconstruction of severely atrophic maxilla for oral rehabilitation with osseointegrated implants.

Avaliação clínica e radiográfica de pacientes submetidos ao levantamento da membrana do seio maxilar

Implant dentistry is a dental specialty which presents great predictability in the rehabilitation at posterior, partially edentulous maxillary areas. Early tooth loss results in significant jaw remodeling. The maxillary sinus lifting followed by implant placement is a predictable technique initially described in 1980. Since then, several different techniques have been investigated varying filling materials and the management of complications in order to provide effective guidance in the rehabilitation of these patients. The current study evaluated ten patients who underwent sinus lifting before implant placement and crown installation. First, a retrospective analysis of the medical records was conducted to obtain information about possible postoperative complications. Clinical and radiographic analyses were performed at baseline and 180 days after surgeries. The sinus lifting with immediate implant placement provided satisfactory outcomes and can be considered a safe procedure. Treatment predictability was demonstrated in 90% of patients and for 86.96% of implants placed. It is important to highlight knowledge of anatomical structures at this area, the use of delicate surgical techniques, and strict patient follow-up.

Avaliação da incorporação de enxerto osseo homogeno fresco congelado em humanos: análise histologica e imuno-histoquímica

Allogeneic, fresh-frozen bone has been used in order to replace bone autografts. However, its osteoinduction and osteoconduction properties are not well-defined in the scientific literature. This work aimed to evaluate samples of homogenous bone grafts in humans by qualitative histological and immunohistochemical analysis. For this, ten pre-selected patients underwent surgical augmentation of bone defects. The homogenous fresh frozen block bone graft was stabilized and fixed by bicortical screws. After six months, the reopening procedure was performed for installation of osseointegrated implants. At this time surgical bone graft samples were removed by means of drill trephine. The samples were fixed in 10% formalin, processed with decalcified paraffin, and stained with hematoxylin and eosin. Immunohistochemistry was performed for the expression of Caspase 3 enzyme. The slides were brought to light microscopy for qualitative histology and immunohistochemistry. The results showed non-vital bone tissue, with few areas of deposition of new bone formation on the amorphous matrix, presence of chronic inflammatory infiltrate with areas of osteomyelitis, and expressive immunolabeling of Caspase 3. Given the methods employed and the results it was concluded that the allograft fresh-frozen block is not incorporated into the recipient bed after a healing period of six months.

Reabilitação de maxila atrófica com tecido ósseo homógeno e prótese fixa implantossuportada

The techniques of bone reconstruction for atrophic maxillae have been improved in order to promote bone tissue growth in both height and thickness. The grafts performed with use of autogenous bone is considered the gold standard by most researchers, for demonstrating osteogenic capacity and not to promote antigenic response. However, this type of grafting is not possible to get bone tissue in large quantity for extensive renovations. In recent years, alternatives have been researched to overcome the limitations of autogenous bone. Several alternatives have been investigated to supply the disadvantages of autogenous bone grafts. In such studies, allogeneic bone grafts which are obtained from individuals with different genetic load, but from the same species have been extensively used. They can be indicated in cases of arthrosplasty, surgical knee reconstruction, and large bone defects as well as in oral and maxillofacial reconstruction. Besides showing great applicability and biocompatibility, this type of bone is available in unlimited quantities. To rehabilitate atrophic maxillae an option that has been performed with high success rate is the reconstruction with bone graft followed by osseointegrated dental implants to rehabilitate the patient aesthetics and functionally. This paper aims to show the feasibility of allogenic bone as material for reconstruction of atrophic maxilla, and subsequent rehabilitation with metal ceramic fixed prosthesis implant and dental restoration with accompanying three years through literature review and clinical case report.

Oclusão em prótese sobre implante - parte I

Osseointegrated implants have specific nature distinguish them from natural teeth making them more susceptible to the efforts generated by mastication. The absence of periodontal ligament, which absorbs the masticatory forces and allows the movement of the teeth interfere with the reception of occlusal loads and therefore the predictability of implants. In the boneimplant interface did not occur the phenomena of dissipation of impact, even the movement induced. Thus, during planning and installation of implant prosthesis, the type and characteristics of occlusal pattern adopted should be established with criteria to be no grounds for future failures. In this regard we highlight the occlusal overload generated by several reasons like the presence of premature contacts, interference during motion excursive, deleterious habits and inappropriate extensions on cantilevers. Thus, the objective is to provide a review of the literature regarding the importance of occlusion in oral rehabilitation with implants. Factors to be considered in establishing a favorable occlusion, consistent with prostheses on implants will be described

Oclusão em prótese sobre implante - parte II

In part I of this article, the factors related to the establishment of a favourable occlusion for the implant prosthodontics as well as its real importance in this kind of rehabilitation were showed up. However, it is known that the occlusal characteristics adopted in implant prosthodontics show specific patterns which must be different between each other in accordance to the type of prosthesis installed. The objective of the second part of this work is to present to the reader, by a literature review, those characteristics, justifying the reason because they must be associated to specific kind of prosthesis for favor the treatment established.

Uso de Redes Neurais ARTMAP Nebulosas para a classificação de padrões em sinais ECoG relacionados ao movimento dos dedos

Pós-graduação em Engenharia Elétrica - FEIS

Biocompatibilidade de primers e adesivo utilizados na confecção de próteses maxilofaciais implantorretidas: análise in vitro

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo comparativo de imunomarcações (OC, VEGF, TRAP) em humanos, nas cirurgia de levantamento do assoalho de seio maxilar utilizando osso autógeno e heterógeno

Pós-graduação em Odontologia - FOA