An investigation of cadmium(II) and nickel(II) adsorption by chitin graft covolymer

Chitin hydrogels of poly(vinylpyrrolidone) (VP) were prepared by means of the hydrogen peroxide graft copolymerization process. The effect of the VP grafted chain on water diffusion through the biopolymer was studied. Fourier transform infrared spectra of the VP-g-Ch showed an increase in the intensities of the hydroxyl and carbonyl stretching bands indicating a reduction in the hydrogen bonding of chitin. An investigation was undertaken regarding the adsorption of nickel(II) and cadmium(II) ions from aqueous solutions by the VP grafted chitin and the effects of the grafting degree on the Cd2+ and Ni2+ sorption were studied. The Cd2+ and Ni2+ adsorption equilibrium data correlate well with the Freundlich equation. The results indicate that the Ch-g-VP graft copolymer under investigation is a potentially powerful chelating material that can be employed for Ni2+ and Cd2+ ion removal from wastewater effluents. (C) 2004 Wiley Periodicals, Inc.

Connective tissue graft to correct peri-implant soft tissue margin: A clinical report

This clinical report describes the use of a subepithelial connective tissue graft to recontour a soft tissue margin discrepancy for a single-implant crown in the anterior maxilla. This procedure demonstrates that the use of soft tissue grafts to correct an esthetic deficiency may be a feasible approach to establish new and stable peri-implant soft tissue contours. The patient presented was followed for 18 months.

Role of polyethylene-graft-glycidyl methacrylate compatibilizer on the biodegradation of poly(epsilon-calprolactone)/cellulose acetate blends

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Radiographic and histomorphometric analysis of bone healing using autogenous graft associated with platelet-rich plasma obtained by 2 different methods

The aim of this study was to conduct radiographic and histomorphometric analysis of bone healing in the calvaria of rabbits, using an autogenous graft associated with PRP obtained by 2 different methods. Thirty rabbits were divided into control and experimental groups. Lesions were produced in the calvaria and filled with autogenous graft ( control) or autogenous graft and PRP obtained by the Anitua or modified Sonnleitner methods. The animals were humanely killed 15 days after surgery and the calvarias were radiographed. The radiographs were digitized to assess the radiographic density. By histologic images of the lesion, the bone matrix was quantified. There were no significant differences in the radiographic density and the bone matrix area between the groups. The association of PRP with autogenous bone did not improve the healing process, irrespective of the method used early during healing.

Autogenous transplantation of rib cartilage preserved in glycerol, after removal of the perichondrium, to the malar process of rats--a histological study (Part I).

Seventy-two male albino rats received autogenous transplants of glycerol-preserved rib cartilage into the malar process. The animals were divided into two groups which received preserved cartilage with or without perichondrium. The implants were well tolerated and removal of the perichondrium enhanced the rate of resorption and bone replacement of the material.

Free autogenous cartilage grafts to the mandible of rats-histological study.

The present study was designed to histologically evaluate the behavior of free autogenous cartilage grafts to the mandible of rats. A 3-mm segment was removed from the last rib of male adult rats and transplanted fresh to a receptor bed prepared on the mandibular ramus. The results showed that the grafts maintained their vitality up to 120 days and the perichondrium was biologically integrated to the osseous bed. Appositional growth of the grafts was found. New bone formation was observed in close proximity to the grafts, but newly formed trabeculae did not arise from perichondrium.

Allogeneic transplants of rib cartilage preserved in 98% glycerol or 70% alcohol into the malar process of rats: a comparative histological study.

A comparative study was made of two methods of cartilage preservation, 98% glycerol and 70% alcohol. Rib cartilage was treated by either of these methods and transplanted into the malar process of rats. Cartilage grafts preserved by both methods were equally well tolerated. Resorption and bone substitution were similar in both groups after 120 days, although resorption was greater for the alcohol-preserved cartilage up until day 30. The possible reduction in antigenicity by the 98% glycerol did not produce any difference of behavior from the cartilage preserved in 70% alcohol.

Inside-out vs. standard vein graft to repair a sensory nerve in rats

Nerve regeneration in a sensory nerve was obtained by the application of different techniques: inside-out vein graft (IOVG group) and standard vein graft (SVG group). These techniques provide a good microenvironment for axon regeneration in motor nerves, but their efficiency for regeneration of sensory nerves is controversial. The saphenous nerve was sectioned and repaired by the inside-out and standard vein graft techniques in rats. After 4, 12, and 20 weeks the graft and the distal stump were observed under electron microscopy. In each studied period, the pattern, diameters, and thickness of the myelin sheaths of the regenerated axons were measured in the graft and distal stump. A comparative study about the regenerated nerve fibers by these two different techniques was performed. Regenerated nerve fibers were prominent in both vein grafts 4 weeks after the surgical procedures. On the other hand, in the distal stump, regenerated nerve fibers were observed only from 12 weeks. In both inside-out vein graft and standard vein graft statistical difference was not observed about the diameters and thickness of the myelinated fibers after 20 weeks. On the other hand, the inside-out group had greater regenerated axon number when compared to the standard group. There is a capillary invasion in both graft and distal stump, especially in the IOVG group. The regenerated axons follow these capillaries all the time like satellite microfascicles. After 20 weeks, the diameters of regenerated fibers repaired by the standard vein graft technique were closer to the normal fibers compared to the inside-out vein graft. On the other hand, the pattern of these regenerated axons was better in the IOVG group.

Treatment of gingival recession: Comparative study between subepithelial connective tissue graft and guided tissue regeneration

Background: Various procedures have been proposed to treat gingival recession, but few studies compare these procedures to each other. The purpose of this study was to evaluate a clinical comparison of subepithelial connective tissue graft (SCTG) and guided tissue regeneration (GTR) with a collagen membrane in the treatment of gingival recessions in humans. Methods: Twenty-four defects were treated in 12 patients who presented canine or pre-molar Miller Class I and/or II bilateral gingival recessions. Both treatments were performed in all patients, and clinical measurements were obtained at baseline and 18 months after surgery. These clinical measurements included gingival recession height (GR), root coverage (RC), probing depth (PD), keratinized tissue width (KT), and final esthetic result. Results: Both SCTG and GTR with a bioabsorbable membrane and bone graft demonstrated significant clinical and esthetic improvement for gingival recession coverage. The SCTG group was statistically significantly better than GTR for height of GR (SCTG = 0.2 mm, GTR = 1.12 mm, P = 0.02) and KT (SCTG = 4.58 mm, GTR = 2.5 mm, P <0.0001). However, PD was statistically significantly better for GTR than SCTG treatment (GTR = 1.66 mm, SCTG = 1.00, P = 0.01). The 2 procedures were statistically similar in root coverage (SCTG = 95.6%, GTR = 84.2%, P = 0.073). The esthetic condition after both treatments was satisfactory (P = 0.024). Conclusions: It was concluded that the gingival recessions treated with the SCTG group were superior for GR, RC, and KT clinical parameters, while GTR demonstrated better PD reduction. The final esthetic results were similar using both techniques.

Collateral cartilage ossification of the distal phalanx in the Brazilian Jumper horse

Collateral cartilage ossification of the distal phalanx in the Brazilian Jumper horse is a common finding. The objective of this study was to evaluate the prevalence and the degree of ossification of the collateral cartilages of the distal phalanx in Brazilian Jumper horses. In an analysis of 652 collateral cartilages from the front feet of 163 horses, 93% of these cartilages had collateral cartilage ossification (P < 0.005), and 7% of these cartilages did not have any type of ossification. In ossified cartilages, 86.4% had ossification beginning from the base, and 6.6% had a separate center of ossification.

Effects of cigarette smoke on the Meckel's cartilage of rat fetus : Morphologic, morphometric and stereologic study

The purpose of this study was to investigate the effects of cigarette smoke on the development of the embryo mandible (Meckel's) cartilage in rat fetuses. When inhaled by female Wistar rats between the 9th and the 12th day of pregnancy, cigarette smoke (5 cigarettes a day) caused intrauterine growth retardation, providing smaller fetuses and placentas. In fetuses from the experimental group, the histopathologic examination revealed a poorly developed Meckel' s cartilage with smaller chondroblasts showing a scanty cytoplasm with spherical and paler central nuclei, as well as more abundant cartilage matrix. Morphometric analysis revealed that Meckel's cartilage lacunae were smaller in the fetuses from the experimental group, although not showing any remarkable alteration in shape. The results suggested that inhalation of cigarette smoke by pregnant rats during the organogenic period induced growth retardation and delayed cellular differentiation in rat fetal Meckel's cartilage.

Cocaine associated with onlay bone graft failure: A clinical and histologic report

This patient report presents an unusual onlay bone graft failure following local cocaine application. Three months after the bone grafting procedure performed in the anterior maxilla for bone volume augmentation, the bone graft was totally exposed in the oral cavity as a result of the rubbing of cocaine on the gingival tissue that covered the bone graft. A histologic view of the removed bone fragment presented not only an area of necrosis but also ample spaces filled with necrosis material and resorption areas. Dental practitioners need to be aware of this phenomenon because such patients often do not report the use of drugs, particularly cocaine. Copyright © 2005 by Lippincott Williams & Wilkins.

Autogenous bone graft with or without a calcium sulfate barrier in the treatment of class II furcation defects: A histologic and histometric study in dogs

Background: The purpose of this study was to histologically evaluate the healing of surgically created Class II furcation defects treated using an autogenous bone (AB) graft with or without a calcium sulfate (CS) barrier. Methods: The second, third, and fourth mandibular premolars (P2, P3, and P4) of six mongrel dogs were used in this study. Class II furcation defects (5 mm in height × 2 mm in depth) were surgically created and immediately treated. Teeth were randomly divided into three groups: group C (control), in which the defect was filled with blood clot; group AB, in which the defect was filled with AB graft; and group AB/CS, in which the defect was filled with AB graft and covered by a CS barrier. Elaps were repositioned to cover all defects. The animals were euthanized 90 days post-surgery. Mesio-distal serial sections were obtained and stained with either hematoxylin and eosin or Masson's trichrome. Histometric, using image-analysis software, and histologic analyses were performed. Linear and area measurements of periodontal healing were evaluated and calculated as a percentage of the original defect. Percentage data were transformed into arccosine for statistical analysis (analysis of variance; P<0.05). Results: Periodontal regeneration in the three groups was similar. Regeneration of bone and connective tissue in the furcation defects was incomplete in most of the specimens. Statistically significant differences were not found in any of the evaluated parameters among the groups. Conclusion: Periodontal healing was similar using surgical debridement alone, AB graft, or AB graft with a CS barrier in the treatment of Class II furcation defects.

Biocompatibility of acellular dermal matrix graft evaluated in culture of murine macrophages

The acellular dermal matrix allograft has been used as an alternative to autogenous palatal mucosal graft. The aim of this study was the evaluation of the biocompatibility of an acellular dermal matrix (AlloDerm®) in culture of macrophages. For hydrogen peroxidase determination we used the method of Pick & Kesari, and the Griess method for nitric oxide determination,. Statistical analysis showed no significant difference (p ≤ 0,05) in the release of nitric oxide and hydrogen peroxide by the macrophages exposed to acellular dermal matrix and the negative control. The results suggest that acellular dermal matrix did not activate the cell inflammatory response.