Graft incorporation and implant osseointegration following the use of autologous and fresh-frozen allogeneic block bone grafts for lateral ridge augmentation

Objectives: To compare autogenous bone (AT) and fresh-frozen allogeneic bone (AL) in terms of histomorphometrical graft incorporation and implant osseointegration after grafting for lateral ridge augmentation in humans. Materials and methods: Thirty-four patients were treated with either AL (20 patients) or AT (14 patients) onlay grafts. During implant installation surgery 6 months after grafting, cylindrical biopsies were harvested perpendicularly to the lateral aspect of the augmented alveolar ridge. Additionally, titanium mini-implants were installed in the grafted regions, also perpendicularly to the ridge; these were biopsied during second-stage surgery. Histological/histomorphometric analysis was performed using decalcified and non-decalcified sections. Results: Histological analysis revealed areas of necrotic bone (NcB) occasionally in contact with or completely engulfed by newly formed vital bone (VB) in both AT and AL groups (55.9 ± 27.6 vs. 43.1 ± 20.3, respectively; P = 0.19). Statistically significant larger amounts of VB (27.6 ± 17.5 vs. 8.4 ± 4.9, respectively; P = 0.0002) and less soft connective tissue (ST) (16.4 ± 15.6 vs. 48.4 ± 18.1, respectively; P ≤ 0.0001) were seen for AT compared with AL. No significant differences were observed between the groups regarding both bone-to-implant contact (BIC) and the bone area between implant threads (BA) on the mini-implant biopsies. Conclusion: Allogeneic bone block grafts may be an option in cases where a limited amount of augmentation is needed, and the future implant can be expected confined within the inner aspect of the bone block. However, the clinical impact of the relatively poor graft incorporation on the long-term performance of oral implants placed in AL grafts remains obscure. © 2013 John Wiley & Sons A/S.

Fate of autologous and fresh-frozen allogeneic block bone grafts used for ridge augmentation. A CBCT-based analysis

Objectives: To evaluate dimensional changes in autologous (AT) and fresh-frozen allogeneic (AL) block bone grafts 6 months after alveolar ridge augmentation. Material and methods: Twenty-six partially or totally edentulous patients treated either with fresh-frozen AL bone or AT bone onlay block grafts prior to implant placement (13 patients in each group), were included in this analysis. Patients received CBCT (i-CAT Classic) examinations prior to surgery and 14 days and 6 months after grafting. Differences in alveolar ridge area among the various observation times were evaluated by planimetric measurements on two-dimensional CBCT images of the grafted regions. Nineteen grafted blocks from each group were evaluated. Results: Significant increase in alveolar ridge dimensions, allowing implant placement, was obtained with both types of grafts 6 months after grafting; no significant differences in alveolar ridge area were observed between the groups at the various observation times. However, graft resorption in the AL group was significantly larger compared to that in the AT group at 6 months. Conclusions: Larger bone graft resorption was seen in patients treated with fresh-frozen AL bone than in those treated with AT bone 6 months following alveolar ridge augmentation. © 2011 John Wiley & Sons A/S.

Regulation of visfatin by microbial and biomechanical signals in PDL cells

Objectives: This in vitro study was established to examine whether visfatin thought to be a link between periodontitis and obesity is produced by periodontal ligament (PDL) cells and, if so, whether its synthesis is modulated by microbial and/or biomechanical signals. Materials and methods: PDL cells seeded on BioFlex® plates were exposed to the oral pathogen Fusobacterium nucleatum ATCC 25586 and/or subjected to biomechanical strain for up to 3 days. Gene expression of visfatin and toll-like receptors (TLR) 2 and 4 was analyzed by RT-PCR, visfatin protein synthesis by ELISA and immunocytochemistry, and NFκB nuclear translocation by immunofluorescence. Results: F. nucleatum upregulated the visfatin expression in a dose- and time-dependent fashion. Preincubation with neutralizing antibodies against TLR2 and TLR4 caused a significant inhibition of the F. nucleatum-upregulated visfatin expression at 1 day. F. nucleatum stimulated the NFκB nuclear translocation. Biomechanical loading reduced the stimulatory effects of F. nucleatum on visfatin expression at 1 and 3 days and also abrogated the F. nucleatum-induced NFκB nuclear translocation at 60 min. Biomechanical loading inhibited significantly the expression of TLR2 and TLR4 at 3 days. The regulatory effects of F. nucleatum and/or biomechanical loading on visfatin expression were also observed at protein level. Conclusions: PDL cells produce visfatin, and this production is enhanced by F. nucleatum. Biomechanical loading seems to be protective against the effects of F. nucleatum on visfatin expression. Clinical relevance: Visfatin produced by periodontal tissues could play a major role in the pathogenesis of periodontitis and the interactions with obesity and other systemic diseases. © 2013 Springer-Verlag Berlin Heidelberg.

The effect of locked screw angulation on the biomechanical properties of the S.P.S. Free-Block plate

Objectives: Among the locked internal fixators is one denominated S.P.S. (Synthesis Pengo System) Free-Block, which was designed with a locking ring that allows the screw to be locked and positioned obliquely. Due to the paucity of biomechanical studies on this system, the present work aimed to evaluate the influence of locked screw angulation on the resistance of the S.P.S. Free--Block plate. Methods: Forty synthetic bone cylinders with 10 mm fracture gap were used. Forty seven-hole 3.5 mm stainless steel plates (two AO-like dynamic compression holes and five locked holes) were assembled according to the orientation of the locked screws: mono cortical screws were positioned at 90° to the long axis of the cylinder (Group 1), and monocortical screws were positioned at 70° to its cylinder long axis (Group 2). In both groups, AO-like dynamic compression hole screws were positioned bicortically and neutrally. For each group, six specimens were tested until failure, three in bending and three in compression, to determine the loads for fatigue testing. Subsequently, for each group, 14 specimens were tested for failure --seven by bending and seven in compression. Results: No significant failure differences were observed between Groups 1 and 2 under static-loading or fatigue test. Clinical significance: In a fracture gap model the orientation of the locked monocortical screws did not show any influence on the mechanical performance of the S.P.S. Free-Block to tests of axial compression and four-point bending. © Schattauer 2013.

Is peripheral blood cell balanced altered by the use of fresh frozen bone block allografts in lateral maxillary ridge augmentation?

Background: The relationship between the immune response and red and white blood cell homeostasis is cited in literature, but no studies regarding the balance of these cell populations following maxillary bone-graft surgeries can be found. Aim: The aim of this study was to evaluate the possible impairments in the blood cell balance following fresh-frozen allogeneic bone-graft augmentation procedures in patients who needed maxillary reconstruction prior to implants. Material and Methods: From 33 patients elected to onlay bone grafting procedures, 20 were treated with fresh-frozen bone allografts and 13 with autologous bone grafts. Five blood samples were collected from each patient in a 6-month period (baseline: 14, 30, 90, and 180 days postsurgery), and the hematological parameters (erythrogram, leukogram, and platelets count) were accessed. Results: All evaluated parameters were within the reference values accepted as normal, and significant differences were found for the eosinophils count when comparing the treatments (30 days, p=.035) and when comparing different periods of evaluation (allograft-treated group, baseline×180 days, p≤.05 and 90×180 days, p≤.01; autograft-treated group, 30×90 days, p≤.05 and 30×180 days, p≤.05). Conclusions: Both autologous and fresh-frozen allogeneic bone grafts did not cause any impairment in the red and white blood cell balance, based on quantitative hemogram analysis, in patients subjected to maxillary reconstruction. © 2011 Wiley Periodicals, Inc.

Automatic microstructural characterization and classification using artificial intelligence techniques on ultrasound signals

Secondary phases such as Laves and carbides are formed during the final solidification stages of nickel based superalloy coatings deposited during the gas tungsten arc welding cold wire process. However, when aged at high temperatures, other phases can precipitate in the microstructure, like the γ″ and δ phases. This work presents a new application and evaluation of artificial intelligent techniques to classify (the background echo and backscattered) ultrasound signals in order to characterize the microstructure of a Ni-based alloy thermally aged at 650 and 950 °C for 10, 100 and 200 h. The background echo and backscattered ultrasound signals were acquired using transducers with frequencies of 4 and 5 MHz. Thus with the use of features extraction techniques, i.e.; detrended fluctuation analysis and the Hurst method, the accuracy and speed in the classification of the secondary phases from ultrasound signals could be studied. The classifiers under study were the recent optimum-path forest (OPF) and the more traditional support vector machines and Bayesian. The experimental results revealed that the OPF classifier was the fastest and most reliable. In addition, the OPF classifier revealed to be a valid and adequate tool for microstructure characterization through ultrasound signals classification due to its speed, sensitivity, accuracy and reliability. © 2013 Elsevier B.V. All rights reserved.

The Role of Wing Pigmentation, UV and Fluorescence as Signals in a Neotropical Damselfly

Pigmentation patterns, ultraviolet reflection and fluorescent emission are often involved in mate recognition and mate quality functions in many animal taxa. We investigated the role of wing ultra-violet reflection, fluorescence emission, and pigmentation on age and sexual signals in the damselfly Mnesarete pudica. In this species, wings are sexually dimorphic in colour and exhibit age dependency: males and females show a smoky black colouration when young, turning red in mature males while it turns brown in females. First, we investigated wing UV patterns through reflectance and emission spectra. Second, behavioural experiments were undertaken to show male and female responses to manipulated wing pigmentation and experimentally reduced UV (UV-). Reflectance spectra of the wings of juvenile and mature males and females were used to show the differences between controls and individuals with manipulated colouration used in the behavioural experiment. UV-reduced, females with wings painted red, and control males and females were tethered and presented to conspecific males and females, and their behavioral responses were recorded. The male red wing pigmentation and females with red wings elicited an aggressive response in territorial males and a sexual response in females. Both males and females showed neutral responses towards individuals with reduced UV. Wing signals of juvenile individuals also provoked neutral responses. These results suggest that UV, together with pigmentation, plays a role during mate recognition in males and females. Other than butterflies and spiders, it seems that fluorescence signals and UV reflectance can also be part of communication in odonates. © 2013 Springer Science+Business Media New York.

O efeito da orientação do parafuso bloqueado nas propriedades biomecânicas da placa S.P.S. Free-Block em corpos de prova nao osteoporóticos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Tomographic follow-up of bone regeneration after bone block harvesting from the mandibular ramus

Autogenous bone is still considered the gold standard, and the applicability of autogenous bone grafts is well established. However, the possibility of second harvesting from the same donor region remains unclear. The aim of this study was to perform a prospective evaluation of hard tissue deposition in the mandibular ramus after bone block harvesting using cone beam computed tomography (CBCT). Twenty-two patients with indications for augmentation procedures using autogenous bone from the mandibular ramus were selected. Three CBCT scans were performed with a tomographic guide before bone harvesting (T1) and at 14 days (T2) and 6 months (T3) after the surgical procedures. Measurements were obtained in 2D (area, mm(2)) and 3D (volume, mm(3)), and were subsequently compared. In the 2D analysis, the mean bone formation rate was 56%, while for the 3D analysis the mean rate was 9.7%. Despite this difference, there was a significant correlation between area and volume measurements. Our findings demonstrated the presence of hard tissue in the mandibular ramus at 6 months after bone harvesting, which suggests that it would be possible to reuse the same region for a second block harvesting. However, the second bone harvesting would involve less bone for transplantation when compared to the first bone harvesting.

Block Bone Graft Fixation ( Onlay): A Modification of the Surgical Technique

Several reconstructive methods of the alveolar ridge have been reported to make possible future rehabilitations with implants. Many of these methods come from studies done in animals, mainly rats. With this clinical practice based on scientific evidence, any experimental procedure that can be undertaken in real life is fundamental. Thus, any research that emulates as closely as possible those techniques used in humans are important. This study describes the modification of the technique for block bone graft fixation (onlay) in rats using the lag screw-type technique, normally used in clinical procedures for grafts in humans. The conclusion was that the execution of the described procedures minimizes interference of blood flow in the area because of the maintenance of the muscle insertion in the buckle aspect of the most anterior region of the mandible, providing better stability to the graft and better contact interface of the graft and receptor bed.

Linkage disequilibrium and haplotype block structure in a composite beef cattle breed

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Water activity of aqueous solutions of ethylene oxide-propylene oxide block copolymers and maltodextrins

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Feature extraction in pressure signals for leak detection in water networks

Techniques based on signal analysis for leak detection in water supply systems typically use long pressure and/or flow data series of variable length. This paper presents the feature extraction from pressure signals and their application to the identification of changes related to the onset of a leak. Example signals were acquired from an experimental laboratory circuit, and features were extracted from temporal domain and from transformed signals. Statistical analysis of features values and a classification method were applied. It was verified the feasibility of using feature vectors for distinguish data acquired in the absence or presence of a leak.

Utilização do bite block para correção da mordida aberta anterior

Bite block is a functional orthodontic appliance that promotes relative intrusion or dental eruption inhibition. The purpose of this study is to present the effects of bite block on the treatment of an open bite case report.