Effect of mechanical cycling on screw torque in external hexagon implants with and without platform switching

This in vitro study evaluated the effect of mechanical cycling on the torque of retaining screw in external hexagon implants with platform switching (PS), regular platform (RP) and wide platform (WP). A total of 30 specimens were equally divided into 3 groups: PS, PR and WP. Each specimen was prepared with implants: 3.75 x 10 mm for RP group and 5.0x10 mm for PS and WP groups and its respective abutment with 32 Ncm torque. All groups were subjected to 106 cycles with 100 N (corresponding to about 40 months of chewing). The results were obtained with the reverse torque of each specimen and data were evaluated using ANOVA and Tukey test (p<0.05). The PS group showed statistically significant difference in screw removal torque (30.06±5.42) compared with RP (23.75±2.76) and WP (21.32±3.53) (p<0.05) groups; the RP and WP groups showed no statistically significant difference between them. It was concluded that the PS group showed higher reverse torque value, suggesting lower susceptibility of the abutment screw loosening.

Verificação da eficiência do modelo de Mohler na resposta do comportamento de vigas mistas de madeira e concreto

The aim of this research study was to evaluate the structural behaviour of the wood and concrete composite system for bridge decks with emphasis on the metal shear connectors. Experimental tests were performed on composite specimens and wood and concrete beams with a metallic connector system in an X position, using CS100900-type screws. All specimens and beams were submitted to static loads until failure in order to obtain the strength and stiffness of the connection system. The experimental results for the stiffness of the beams were compared with the analytical results obtained through the Mohler model, presenting good equivalence for service loads. The experimental results obtained demonstrate that the most significant damage in composite systems occurred in the connectors' areas.

Aumento de gengiva queratinizada em mucosa peri-implantar

Introduction: Recent studies have evaluated the relationship between the width of keratinized mucosa and peri-implant tissue health. Insufficiently wide keratinized tissue can be increased surgically, for example by free gingival grafting. The presence or reconstruction of keratinized tissue around the implant can facilitate restorative procedures, promote aesthetics and allow the maintenance of an oral hygiene routine without irritation or discomfort to the patient. Objective: To describe a patient who underwent free gingival graft surgery to increase the width of keratinized tissue in the region of previously implants to support a type of prosthetic protocol. Case report: A patient who had received dental implants to support a type of prosthetic protocol presented with inflamed peri-implant mucosa, but with no keratinized tissue. Free gingival tissue was obtained from the palate and grafted into the anterior maxilla. Sixty days after muco-gingival surgery, we observed that the free gingival graft favored peri-implant health and prosthetic casting. Conclusion: The free gingival graft technique is both easy to perform and effective in increasing the width of keratinized mucosa following implantation.

Controvérsias no tratamento das fraturas mandibulares em crianças: relato de caso clínico

Introduction: The treatment of mandibular fractures has undergone many changes, especially after the introduction of rigid internal fixation techniques. Currently, the use of resorbable materials presents some advantages over metallic devices, particularly when applied in children. Objective: The authors discuss the controversies involved in the treatment of mandibular fractures in children, mainly related to fixation of fractures. Case Report: In this paper, we present a case of a 5 years treatment patient with mandibular angle fracture treated by open reduction and internal fixation with plates and screws. Final Comments: Aiming to not interfere in the development of tooth germs and mandibular bone growth a second surgery for removal of the fixation devices is indicated.

Reconstrução imediata de fenestração peri-implantar com enxerto autógeno em bloco de ramo mandibular

Alveolar wall fenestrations are common during implant placement. The aim of this paper is to report a case where a peri-implant bone fenestration was reconstructed immediately after implant placement by an autogenous mandibular bone block. A male patient was referred to the Department of Surgical and Integrated Clinics to substitute his Kennedy´s Class IV removable partial denture for an implantsupported fixed prosthesis. A peri-implant bone fenestration at the buccal wall was seen at the region of 12, being reconstructed by a mandibular bone block secured by a bicortical screw. Six months later the surgical procedures, an implant-supported complete fixed partial prosthesis was developed. The autogenous bone block harvested from the mandibular ramus was a safe alternative to reconstruct the peri-implant bone defect such as fenestration types.

Adesivo tecidual de fibrina e sua aplicação na implantodontia

The purpose of this literature review was to evaluate the use of fibrin tissue adhesive in implant dentistry. Materials and Methods: A literature search of Medline-PubMed for articles published, describing the use of fibrin tissue adhesive in implant dentistry was performed and articles were critically reviewed. Results: The literature review reveals clinical trials and experimental studies with regard to the use of fibrin tissue adhesive in implant dentistry. This material consists of 2 components: highly purified, freeze-dried human fibrinogen with factor XIII and a starter solution containing human thrombin. Clotting factor XIII is admitted for reinforcement of the fibrin network. The components are reconstituted before use and when mixed form a clot by mimicking the terminal phase of the physiological clotting cascade. Several studies showed that fibrin tissue adhesive is fully absorbed by macrophages within 2 weeks of application. Adhesive fibrin tissue may be used for to prevent bone loss, to create contour in the periimplant soft tissue and osseous tissue, to sculpt emergence profile for prosthetic components and to mimic tissue architecture. In the last years fibrin tissue adhesive also find use as material for the controlled delivery of drugs and biologics. Conclusions: The fibrin tissue adhesive presents good properties such as biocompatibility, hemostatic properties and ability to break down like the physiologic clot. This material, alone or associated with other materials, can be used with the implants immediately after extraction. In this condition it brings the necessary anchoring and efficient maintenance of osseous/mucosal contour, which it is important for the clinical success.

Aspectos clínicos influentes no planejamento das próteses sobre implantes tipo overdenture e protocolo

The aim of his study was to review the current scientific literature in order to discuss the surgical, prosthetics and psychological/psychosocial aspects during the treatment planning of edentulous patients, when a total fixed prosthesis or overdenture is indicated. To identify studies to take part in this review, a search was conducted for the following databases: PubMed, Dentistry and Oral Sciences Source, Journals@Ovid, SpringerLink, Wiley Online Library, Nature (NPG), Oxford Journals. It was used as descriptors: total fixed prostheses and overdentures. Inclusion criteria were: clinical articles, clinical case reports, case series, literature reviews and systematic reviews that addressed the study and comparison of total fixed prostheses and overdentures for a surgical- prosthetic planning. Exclusion criteria were: laboratory and in vitro studies and those whose first language was not English or Portuguese. Of a total of 454 articles, after an analysis according to inclusion and exclusion criteria, 76 articles were selected. During an implantsupported prosthesis rehabilitation with dental in edentulous patients, the use of alternative procedures appear to be effective when compared to more invasive surgical techniques, and thus, the amount of dental implants possible to install associated with prosthetic issues such as lip support, smile line, quantity and quality of mucosa, phonetics, etc., will allow an appropriate treatment planning to each clinical case

Uso de implantes zigomáticos na fixação de próteses bucomaxilofaciais

The maxillofacial prosthetic rehabilitation aims of individuals with craniofacial deformities resulting from trauma, congenital malformations or tumors. Many researches have been done to improve the stability and retention of dentures in patients. With the advent of osseointegration, the maxillofacial prosthesis suffered a major advance making possible the realization of prosthetic works with stability, aesthetic quality and predictable results. This paper reviews the literature regarding the use of zygomatic implants in the fixation of maxillofacial prostheses.

Manutenção em próteses implantossuportadas: higiene oral

The maintenance of Implant-supported Prosthesis is essential to the success of dental implants. Therefore, the aim of the study was to conduct a review the literature addressing maintenance Implant-Supported Prosthesis in order to guide planning for the longevity of oral rehabilitation. We conducted a detailed search strategy for the Pubmed / Medline Dentistry and Oral Science, used as descriptors: “Oral Hygiene“ and “Dental Implant until July, 2013. The results were grouped together in topics (Clinical Exam and Oral Hygiene) and discussed. Conclusion: A regular maintenance program for oral patient implantprosthesis is essential to the longevity of the treatment. Different methods and devices are effective for cleansing. However one orientation (in writing) must be offered to patients, since inadequate cleaning can create regions of abrasion on the surfaces of abutments and dental implants.

Reabilitação total bimaxilar e o restabelecimento da tríade: função, fonética e estética

O tratamento de indivíduos totalmente desdentados, desde os primórdios dos conceitos e fundamentos da reabilita-ção oral, tem sido um grande desafio para os profissionais da odontologia, especialmente em relação à retenção, suporte e estabilidade das próteses totais. Esses pré-requisitos protéticos estão geralmente deficientes em pacientes que apresentam um longo período de desdentamento, com grande atrofia e reabsor-ção dos rebordos alveolares, especialmente no arco mandibular. Com o advento da implantodontia e com a evolução sequencial dos estudos envolvendo o processo de osseointegração essa filosofia se tornou otimizada pelas próteses totais fixas implantossuportadas, denominadas próteses protocolo, repre-sentando uma modalidade clinicamente previsível no âmbito da dontologia moderna. Com base nessa premissa, o objetivo do presente trabalho é elucidar a sequência clínica de uma reabilitação total bimaxilar, conjugando-se uma prótese total convencional superior e uma prótese protocolo inferior.

Relation between bruxism and dental implants

OBJECTIVE: The aim of this study was to gather information and discuss the predictability of implant-supported prostheses in patients with bruxism by performing a literature review. METHODS: In order to select the studies included in this review, a detailed search was performed in PubMed and Medline databases, using the following key words: bruxism, dental implants, implant supported prosthesis, and dental restoration failure. Items that were included are: case reports, randomized controlled trials, in vitro studies, literature and systematic reviews, with or without meta-analysis, of the last 20 years that addressed the theme. Articles without abstracts, animal studies, articles in languages other than English and articles from journals unrelated to the dental field were excluded. RESULTS: after analysis according to inclusion and exclusion criteria, 28 articles were selected from a total of 54. It is known from the array of scientific articles which have assessed, either through retrospective, prospective or experimental studies, that the biomechanical and biological impact of bruxism on implant-supported prostheses is small, and that the literature has contributed little to exemplify the prosthetic limits of safety for the specialist from a clinical point of view. CONCLUSION: Although there is still no general consensus on this matter, most of the literature review articles do provide clinical guidelines that contribute to implant supported prostheses longevity and stability in patients with bruxism.

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.

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.

Projeto estrutural de um conector bipartido utilizado na indústria de óleo & gás através do método dos elementos finitos

Pós-graduação em Engenharia Mecânica - FEG

Ex vivo torsional properties of the Targon Vet Nail System in canine femurs: comparison with the 2.4 mm LC-DCP Plate

Pós-graduação em Cirurgia Veterinária - FCAV