Histologic and histometric evaluation of calvarial autogenous bone graft in reconstruction of atrophyc maxilla for dental implants

The calvarial bone is highlighted as a good donor area for large reconstructions of atrophic jaw for subsequent rehabilitation with implant-supported prosthesis. The aim of this study was to observe and measure through histological and histometric evaluation, the cellular events that occur at the interface of union from onlay parietal bone graft on the maxilla of 10 patients, after a period of 6 months of incorporation. The biopsies were performed at the time of installation of osseointegrated implants. The bone contact area represented 78.75% and connective contact 21.25%. The region of connective union between the bone graft to the maxillae presented new bone formation (41.26%), marrow bone (36.06%), osteoid tissue (15.86%) and connective tissue (6.80%). All samples had good graft incorporation to the receptor bed with osteogenic activity and absence of inflammatory cells.

Improvement of the alcohol dehydrogenase from baker's yeast using polymers and salts for alcohol determinations in beverages

An alcohol dehydrogenase (ADH) was purified from dry baker’s yeast. This is a key enzyme of the primary short-chain alcohol metabolism in many organisms. In the present study, the obtained enzymatic preparation of baker’s yeast, containing 2.7 U/mg of ADH, was used in the reactions. The purified extract of the ADH obtained from Fermix commercial dry yeast, presented the highest activity and purification factor when ammonium sulfate was added in the precipitation of protein, in the range 35-60% (w/v). The enzymatic preparation was maintained for 2 months in the lyophilized form at 4ºC (retention of 96.2% of activity) in the presence of 1 mmol/L of sodium azide, and it maintained 47% of activity for 30 days at 30°C in the presence of 15% PEG. The assays of ethanol (detection range 5 mM -150 mM or 2.3 x 10-4 – 6.91 x 10-3g/L) in different samples in alcoholic beverages, presented a maximum deviation of only 2.1%. Assays of recovery of the substrate (99.25%) added in the wine showed that the methodology is viable for this sample type. The standard curve and the analytic curve of this method meet the conditions of precision, sensitivity, simplicity, and low cost, required for a useable analytical method.

Immunohistochemical, tomographic, and histological study on onlay bone graft remodeling. Part III: allografts

Objective In the last decades aroused the interest for bone tissue bank as an alternative to autogenous grafting, avoiding donor sites morbidity, surgical time, and costs reduction. The purpose of the study was to compare allografts (ALg) with autografts (AUg) using histology, immunochemistry, and tomographic analysis. Material and methods Fifty-six New Zealand White rabbits were submitted to surgical procedures. Twenty animals were donors and 36 were actually submitted to onlay grafting with ALg (experimental group) and AUg (control group) randomly placed bilaterally in the mandible. Six animals of each group were sacrificed at 3, 5, 7, 10, 20, and 60 postoperative days. Immunolabeling was accomplished with osteoprotegerin (OPG); receptor activator of nuclear factor-k ligand (RANKL); alkaline phosphatase (ALP); osteopontin (OPN); vascular endothelial growth factor (VEGF); tartrate-resistant acid phosphatase (TRAP); collagen type I (COL I); and osteocalcin (OC). Density and volume of the grafts was evaluated on tomography obtained at the surgery and sacrifice. Results The ALg and AUg exhibited similar patterns of density and volume throughout the experiments. The intra-group data showed statistical differences at days 7 and 60 in comparison with other time points (P = 0.001), in both groups. A slight graft expansion from fixation until day 20 (P = 0.532) was observed in the AUg group and then resorbed significantly at the day 60 (P = 0.015). ALg volume remained stable until day 7 and decreased at day 10 (P = 0.045). The light microscopy analysis showed more efficient incorporation of AUg onto the recipient bed if compared with the ALg group. The immunohistochemical labeling picked: at days 10 and 20 with OPG in the AUg group and at day 7 with TRAP in the ALg group (P = 0.001 and P = 0.002, respectively). Conclusions ALg and AUg were not differing in patterns of volume and density during entire experiment. Histological data exhibit more efficient AUg incorporation into recipient bed compared with the ALg group. Immunohistochemistry outcomes demonstrated similar pattern for both ALg and AUg groups, except for an increasing resorption activity in the ALg group mediated by TRAP and in the AUg group by higher OPG labeling. However, this latter observation does not seem to influence clinical outcomes.

Reconstruction of maxillary ridge atrophy caused by dentoalveolar trauma, using autogenous block bone graft harvested from chin: a case report

Background Dentoalveolar trauma, especially when involving front teeth, negatively affect the patient’s life; in particular, tooth avulsion is a complex injury that affects multiple tissues, and no treatment option offers stable long-term outcomes. The aim of this study was to report a case of reconstruction of atrophic anterior alveolar ridge after tooth loss, performed with autograft harvested from the chin, and subsequent prosthetic rehabilitation with the use of an osseointegrated implant. Case report A 23-years-old Caucasian girl, presented an atrophic alveolar bone in the area of tooth 11, as a result of tooth resorption 10 years after a tooth reimplantation procedure. Reconstruction was performed with autogenous bone harvested from the chin. After 6-months healing period to allow autograft incorporation, a dental implant was inserted. After further 6- months, a screw-retained implant supported metal-ceramic prosthesis was fabricated. Results The prosthetic rehabilitation was successful, and after a follow-up period of 5 years, the achieved result was stable.Conclusion It can be concluded that the autogenous bone graft harvested from the chin, is a safe and effective option for alveolar ridge defects reconstruction, allowing a subsequent placement of a dental implant supporting a prosthetic restoration.

Reconstruction of maxillary ridge atrophy caused by sequela of dentoalveolar trauma with autogenous bone graft harvested from mentum

Dentoalveolar traumatisms, particularly those that affect the anterior teeth, interfere adversely in the patient s life.Among them, tooth avulsion is pointed out because it is characterized as a complex injury that affects multiple tissues, andbecause there is no effective treatment available for its resolution with a stable long-term outcome.Aim/Hypothesis: The aim of the present study was to relate a clinical case of complete reconstruction of atrophy of the alveolarbone corresponding to tooth 11, lost by tooth resorption 10 years after the tooth reimplantation procedure.Material and methods: Reconstruction was performed with autogenous bone harvested from the mentum donor site. Surgicalaccess began in the receptor area with a Newman mucoperiosteal incision using a scalpel blade 15 mounted in a scalpel handlefor detachment and exposure of the receptor site. Extensive bone resorption was observed in the vestibular-palatine direction,proved by the thinness of the receptor bed. Decorticalization of the vestibular bone plate was performed. After preparing thereceptor bed, and incision was made in the mucosa in the depth of the anterior vestibular fornix, then a perpendicular muscleperiostealincision to detach and exposure the donor area. The bone graft necessary for reconstruction of the donor area wasdelimited, followed by monocortical osteotomy and the monocortical graft was removed. The next stage was to perform shapingfor passive graft accommodation and fixation by means of two bicortical screws. After fixation of the graft the sharp angles wererounded off in order to avoid possible exposure and/or fenestrations of the reconstructed area, then the receptor and donor areawere sutured. After the 6-month period to allow incorporation of the autogenous graft, an osseointegrated dental implant wasinserted. At the end of the 6-month period of waiting for osseointegration to occur, the process of fabricating the screw-retainedmetal ceramic

Particularities in the technique of calvaria graft

Calvaria grafts provide good bone quantity for the reconstruction of the atrophic maxilla, and have lower morbidity and resorption rates when compared to iliac crest. The aim of this paper is to present the technique for obtaining a graft of the skull. Initially, the depth of the osteotomy is determined by a manually conducted bur, which establishes the limits of the structures of the skull (outer table, diploe and inner table), making the removal of bone blocks easier and safer. Thus, osteotomies of the blocks are made with greater security, avoiding the complications inherent to surgical technique. The case that will be presented it is from a male patient of 65 years who refused to submit to the iliac crest graft, opting for the calvaria, despite being bald, that is a contraindication for this treatment modality. A delicate suture associated with placement of titanium mesh to maintain the conformation of the patient's skull in the region of the bone defect, created after removal of the graft, provided a good cosmetic result at the donor site. The use of titanium mesh for re-anatomization of bone defects created in the grafts is well indicated for bald patients.

Gamma-ray dosimetric properties of conjugated polymers in solution

The effect of gamma radiation on poly{[2,5-bis(3-(N,N-diethylamino)-1-oxapropyl)-1,4-phenylene]-alt-1,4- phenylene} (PPP); poly{[2,5-bis(3-(N,N-diethylammonium bromide)-1-oxapropyl)-1,4-phenylene]-alt-1,4-phenylene} (PPP-Br); and the polymerized dye poly-1-ethyl-2-[3-(1-ethyl-1,3-dihydro-3,3-dimethyl-2H-indol-2-ylidene)-1-propenyl]- 3,3-dimethyl-3H-indolium perchlorate (Poly-CyC) has been investigated. The stability and response of poly [2-methoxy- 5-(2'- ethyl-hexyloxy)-p-phenylenevinylene] (MEH-PPV) in mixed solutions have also been explored. To this end, samples with concentrations ranging from 0.005 to 0.500 mg/mL were irradiated with a 60Co gamma-ray source at room temperature, using doses up to 1 kGy, and the response was analyzed by UV-Vis spectroscopy. The obtained results reinforce the previously proposed mechanism and suggest that the effect depends on specific structural characteristics of the main chain of the polymers. Moreover, the polymerized dyes display interesting dosimetric properties. Additionally, it has been noted that, contrary to what happens in other solvents, MEH-PPV is degraded in bromoform solution. Protective effects have also been observed for bromoform+toluene mixtures (1:1 vol/vol) and solutions containing molecular dyes. - See more at: http://www.eurekaselect.com/117251/article#sthash.gHFnYvJk.dpuf

Oral chronic graft-versus-host disease: analysis of dendritic cells subpopulations

The graft-versus-host disease is the major cause of morbidity and mortality in patients who have undergone hematopoietic stem cell transplantation. Aiming at contributing to the understanding of the role of myeloid and plasmacytoid dendritic cells, and natural killer cells in chronic graft-versus-host disease, we examined biopsies of jugal mucosa of 26 patients with acute myeloid leukemia who had undergone allogenic hematopoietic stem cell transplantation. Half of these patients developed oral chronic graft-versus-host disease. Microscopic sections were immunohistochemically stained for anti-CD1a, anti-CD123 and anti-CD56. We calculated the number of immunostained cells in the corium per square millimeter and applied the Mann-Whitney test. Results showed a statistically significant increase of myeloid dendritic cells (CD1a+; p=0,02) and natural killer cells (CD56; p=0,04) in patients with oral chronic graft-versus-host disease. CD123 immunostaining showed no statistical difference between groups. It was concluded that myeloid dendritic cells and natural killer cells participate in the development of oral chronic graft-versus-host disease.

Understanding the Grafting of Telechelic Polymers on a Solid Substrate to Form Loops

Recent experimental and theoretical studies have demonstrated that relative to singly tethered chains, the presence of polymer loops at interfaces significantly improves interfacial properties such as adhesion, friction, and wettability. In the present study, a simple system was studied to examine the formation of polymeric loops on a solid surface, where the grafting of carboxylic acid terminated telechelic polystyrene from the melt to an epoxy functionalized silicon is chosen. The impact of telechelic molecular weight, grafting temperature, and surface functionality on the telechelic attachment process is studied. It was found that grafting of the telechelic to the surface at both ends to form loops is the primary product of this grafting process. Moreover, examination of the kinetics of the grafting process indicates that it is reaction controlled. Fluorescence tagging of the dangling ends of singly bound chains provides a mechanism to monitor their time evolution during grafting, and these results indicate that the grafting process is accurately described by recent Monte Carlo simulation work. The results also provide a method to control the extent of loop formation at interfaces and therefore provide an opportunity to further understand the role of the loops in the interfacial properties in multicomponent polymer systems.

MECHANICAL TESTING DEVICE FOR VISCOELASTIC BIOMATERIALS

Nearly all biologic tissues exhibit viscoelastic behavior. This behavior is characterized by hysteresis in the response of the material to load or strain. This information can be utilized in extrapolation of life expectancy of vascular implant materials including native tissues and synthetic materials. This behavior is exhibited in many engineering materials as well such as the polymers PTFE, polyamide, polyethylene, etc. While procedures have been developed for evaluating the engineering polymers the techniques for biologic tissues are not as mature. There are multiple reasons for this. A major one is a cultural divide between the medical and engineering communities. Biomedical engineers are beginning to fill that void. A digitally controlled drivetrain designed to evaluate both elastic and viscoelastic characteristics of biologic tissues has been developed. The initial impetus for the development of this device was to evaluate the potential for human umbilical tissue to serve as a vascular graft material. The consequence is that the load frame is configured for membrane type specimens with rectangular dimensions of no more than 25mm per side. The designed load capacity of the drivetrain is to impose an axial load of 40N on the specimen. This drivetrain is capable of assessing the viscoelastic response of the specimens by four different test modes: stress relaxation, creep, harmonic induced oscillations, and controlled strain rate tests. The fluorocarbon PTFE has mechanical properties commensurate with vascular tissue. In fact, it has been used for vascular grafts in patients who have been victims of various traumas. Hardware and software validation of the device was accomplished by testing PTFE and comparing the results to properties that have been published by both researchers and manufacturers.

Charge generation, charge transport, and residual charge in the electrospinning of polymers: A review of issues and complications

Electrospinning has become a widely implemented technique for the generation of nonwoven mats that are useful in tissue engineering and filter applications. The overriding factor that has contributed to the popularity of this method is the ease with which fibers with submicron diameters can be produced. Fibers on that size scale are comparable to protein filaments that are observed in the extracellular matrix. The apparatus and procedures for conducting electrospinning experiments are ostensibly simple. While it is rarely reported in the literature on this topic, any experience with this method of fiber spinning reveals substantial ambiguities in how the process can be controlled to generate reproducible results. The simplicity of the procedure belies the complexity of the physical processes that determine the electrospinning process dynamics. In this article, three process domains and the physical domain of charge interaction are identified as important in electrospinning: (a) creation of charge carriers, (b) charge transport, (c) residual charge. The initial event that enables electrospinning is the generation of region of excess charge in the fluid that is to be electrospun. The electrostatic forces that develop on this region of charged fluid in the presence of a high potential result in the ejection of a fluid jet that solidifies into the resulting fiber. The transport of charge from the charge solution to the grounded collection device produces some of the current which is observed. That transport can occur by the fluid jet and through the atmosphere surrounding the electrospinning apparatus. Charges that are created in the fluid that are not dissipated remain in the solidified fiber as residual charges. The physics of each of these domains in the electrospinning process is summarized in terms of the current understanding, and possible sources of ambiguity in the implementation of this technique are indicated. Directions for future research to further articulate the behavior of the electrospinning process are suggested. (C) 2012 American Institute of Physics. [doi: 10.1063/1.3682464]

Acellular dermal matrix graft with or without enamel matrix derivative for root coverage in smokers: a randomized clinical study

Aim: The aim of this randomized controlled clinical study was to compare the use of an acellular dermal matrix graft (ADMG) with or without the enamel matrix derivative (EMD) in smokers to evaluate which procedure would provide better root coverage. Material and Methods: Nineteen smokers with bilateral Miller Class I or II gingival recessions >= 3 mm were selected. The test group was treated with an association of ADMG and EMD, and the control group with ADMG alone. Probing depth, relative clinical attachment level, gingival recession height, gingival recession width, keratinized tissue width and keratinized tissue thickness were evaluated before the surgeries and after 6 months. Wilcoxon test was used for the statistical analysis at significance level of 5%. Results: No significant differences were found between groups in all parameters at baseline. The mean gain recession height between baseline and 6 months and the complete root coverage favored the test group (p = 0.042, p = 0.019 respectively). Conclusion: Smoking may negatively affect the results achieved through periodontal plastic procedures; however, the association of ADMG and EMD is beneficial in the root coverage of gingival recessions in smokers, 6 months after the surgery.

A Randomized comparative clinical study of two surgical procedures to improve root coverage with the acellular dermal matrix graft

Aim This randomized, controlled, clinical study compared two surgical techniques for root coverage with the acellular dermal matrix graft (ADMG) to evaluate which procedure could provide better root coverage and greater amounts of keratinized tissue. Materials and Methods Fifteen pairs of bilateral Miller Class I or II gingival recessions were treated and assigned randomly to the test group, and the contra-lateral recessions were assigned to the control group. The ADMG was used in both groups. In the control group, the graft and flap were positioned at the level of the cemento-enamel junction (CEJ), and in the test group, the graft was positioned 1 mm apical to the CEJ and the flap 1 mm coronal to the CEJ. The clinical parameters were taken before the surgeries and after 6 months. The gingival recession area, a new parameter, was measured in standardized photographs through a special device and software. Results There were statistically significant differences favouring the proposed technique for all parameters except for the amount of keratinized tissue at 6 months. Conclusions The proposed test technique is more suitable for root coverage procedures with ADMG, and the new parameter evaluated appears valuable for root coverage analysis. (Clinicaltrials.gov Identifier: NCT01175720).

Hb S-Sao Paulo: A new sickling hemoglobin with stable polymers and decreased oxygen affinity

Hb S-Sao Paulo (SP) [HBB:c.20A > T p.Glu6Val: c.196A > G p.Lys65Glu] is a new double-mutant hemoglobin that was found in heterozygosis in an 18-month-old Brazilian male with moderate anemia. It behaves like Hb S in acid electrophoresis, isoelectric focusing and solubility testing but shows different behavior in alkaline electrophoresis, cation-exchange HPLC and RP-HPLC. The variant is slightly unstable, showed reduced oxygen affinity and also appeared to form polymers more stable than the Hb S. Molecular dynamics simulation suggests that the polymerization is favored by interfacial electrostatic interactions. This provides a plausible explanation for some of the reported experimental observations. (C) 2012 Elsevier Inc. All rights reserved.