Avaliação mecânica in vitro utilizando miniplacas quadradas e retangulares do sistema 2.0 mm em fraturas da região anterior de mandíbula

The aim of this study was to comparatively evaluate the mechanical strength of squared and rectangular 2.0 mm system miniplates comparing them to the standard configuration with 2 straight miniplates in stabilizing fractures in the anterior mandible. Ninety synthetic polyurethane mandible replicas were used in mechanical test. The samples were divided into six groups of three different methods for fixation. Groups 1, 2 and 3 showed complete fractures in symphysis, characterized by a linear separation between the medial incisor, and groups 4, 5 and 6 showed complete fractures in parasymphysis with oblique design. Groups 1 and 4 were represented by the standard technique with two straight miniplates parallel to each other. Groups 2 and 5 were stabilized by squared miniplates and groups 3 and 6 were fixed by rectangular design. Each group was subjected to a mechanical test at a displacement speed of 10 mm/min on a universal testing machine, receiving linear vertical load on the region of the left first molar. The values of the maximum load and when displacements reached 5 mm were obtained and statistically analyzed by calculating the confidence interval of 95%. Fixation systems using squared (G2) and rectangular (G3) miniplates obtained similar results. No statistically significant differences with respect to the maximum load and the load at 5 mm displacement were found when compared to standard method in symphyseal fractures (G1). In parasymphysis the fixation method using squared miniplates (G5) obtained results without significant differences regarding the maximum load and the load at 5 mm when compared to the standard configuration (G4). The fixation method using rectangular miniplates (G6) showed inferior results which were statistically significant when compared to the standard configuration (G4) for parasymphysis fractures. The mechanical behavior of the fixation methods was similar, except when rectangular miniplates were used. The fixation methods showed better results with statistical significance in symphyseal fractures

Avaliação clínica e radiográfica das complicações técnicas em próteses sobre implantes

The evaluation criteria of the cases treated with dental implants are based on clinical and radiographic tests. In this context it is important to conduct research to determine prognosis of different types of prosthetic rehabilitation and determination of the main problems affecting this type of treatment. Thus, the objective of this study was to assess the prosthetic conditions of individuals rehabilitated with implant-supported prosthesis. In this cross-sectional study 153 patients were treated, accounting for a sample of 509 implants. The failures were observed by clinical and radiographic examination. The results showed that the fracture (0.2%) loss (0.4%) and loosening of the screws (3.3%) were failures are less frequent. The fracture structures as the resin (12.4%), porcelain (5.5%) and metallic (1.5%), loss of resin that covers the screw (23.8%) and loss of retention overdentures on implants (18.6%) had a higher occurrence. The failure of adaptation between the abutment and the implant (6.9%) and especially between the prosthesis and the abutment (25.4%) had a high prevalence and, when related to other parameters showed a significant association, particularly with the cemented prosthesis (OR = 6.79). It can be concluded that to minimize the appearance of failures, protocols must be observed from diagnosis to the settlement and control of prostheses on implants, particularly with respect to technical steps of the making of the prosthesis and care in radiographic evaluating the fit between their components

Uma ferramenta didática para ajudar na fixação dos conceitos introdutórios de análise combinatória

Humans, as well as some animals are born gifted with the ability to perceive quantities. The needs that came from the evolution of societies and technological resources make the the optimization of such counting methods necessary. Although necessary and useful, there are a lot of diculties in the teaching of such methods.In order to broaden the range of available tools to teach Combinatorial Analysis, a owchart is presented in this work with the goal of helping the students to x the initial concepts of such subject via pratical exercises