Maxillary Bone Defect Reconstruction Using Porous Polyethylene Implants

Purpose: The aim of this study was to evaluate the bone repair process in the maxillary sinus in monkeys treated with high-density porous polyethylene (Medpor)Methods: Four capuchin monkeys (Cebus apella) were submitted to bilateral horizontal osteotomies in the anterior wall of the maxillary sinus and divided into 2 groups: control group, left side with no implants, and porous polyethylene group, right side with Medpor. After a period of 145 days after implant placement, the maxillae were removed for histologic and histometric analyses.Results: Bone repair in osteotomized areas took place by connective tissue in 58.5% and 58.7% in the control group and the porous polyethylene group, respectively. In the contact surface with Medpor, bone repair occurred in 41.3%.Conclusions: Medpor was not reabsorbed within the period of this study and allowed bone repair surrounding it. The porous polyethylene constitutes a feasible alternative for bone defect reconstruction.

Correction of a Mucogingival Defect Using an Implant-Retained Postoperative Stent in a Severely Resorbed Mandible: Case Report

This case report describes a technique that uses a palatal mucosal graft and an acrylic resin postoperative stent in an attempt to increase the layer of keratinized tissue around osseointegrated implants in an atrophic mandible. During second-stage surgery a split-thickness labial flap is reflected and apically repositioned by being sutured onto the periosteum and connective tissue. A palatal mucosal graft is then sutured onto the recipient site. The stent is worn for at least 4 weeks following surgery. This procedure helps to eliminate mobility of the mucosa in the area, deepen the vestibule, and prevent muscle reinsertion. (Int J Periodontics Restorative Dent 2008;28:617-623.)

Surgical and Prosthetic Rehabilitation of Patients With Hemimandibular Defect

Purpose: This work intended to investigate, by means of a literature revision, the techniques and materials used for the rehabilitation of hemimandibular defect patients, prosthetic and occlusal aspects of these patients, and chewing and swallowing.Materials and Methods: For the confection of this revision, we consulted the database indexers Google Scholar, PubMed, and SciELO and found studies published between the periods 1972 and 2008. The terms used for the search had been "to hemimandibular defects," "to temporomandibular joint protheses," and "vascularized cap grafts," which had been searched separately and combined.Conclusions: Diverse techniques and materials used for the reconstruction of hemimandibular defects exist; however, great bone resorption is still observed, which will compromise the prosthetic rehabilitation of these patients. More prospective works and stories of clinical cases duly registered will be able to elucidate in a clearer form the anatomic and functional devolutions of the verbal socket of hemimandibular defect patients.

Accuracy of zoomed digital image in the detection of periodontal bone defect: in vitro study

Objectives: (1) To evaluate the intraobserver agreement related to image interpretation and (2) to compare the accuracy of 100%, 200% and 400% zoomed digital images in the detection of simulated periodontal bone defects.Methods: Periodontal bone defects were created in 60 pig hemi-mandibles with slow-speed burs 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm and 3.0 mm in diameter. 180 standardized digital radiographs were made using Schick sensor and evaluated at 100%, 200% and 400% zooming. The intraobserver agreement was estimated by Kappa statistic (kappa). For the evaluation of diagnostic accuracy receiver operating characteristic (ROC) analysis was performed followed by chi-square test to compare the areas under ROC curves according to each level of zooming.Results: For 100%, 200% and 400% zooming the intraobserver agreement was moderate (kappa = 0.48, kappa = 0.54 and kappa = 0.43, respectively) and there were similar performances in the discrimination capacity, with ROC areas of 0.8611 (95% CI: 0.7660-0.9562), 0.8600 (95% CI: 0.7659-0.9540), and 0.8368 (95% CI: 0.7346-0.9390), respectively, with no statistical significant differences (chi(2)-test; P = 0.8440).Conclusions: A moderate intraobserver agreement was observed in the classification of periodontal bone defects and the 100%, 200% and 400% zoomed digital images presented similar performances in the detection of periodontal bone defects.

Ultrastructure of spermiogenesis and spermatozoa of Gymnotus cf. anguillaris and Brachyhypopomus cf. pinnicaudatus (Teleostei : Gymnotiformes)

The ultrastructure of spermiogenic stages and spermatozoa of representatives of two gymnotiform families, Gymnotus cf. anguillaris (Gymnotidae) and Brachyhypopomus cf. pinnicaudatus (Hypopomidae) were studied. Spermiogenesis of both species is characterized by lateral development of the flagellum and formation of a nuclear fossa. Some differences were found between these species, such as whether (B. cf. pinnicaudatus) or not (G. cf. anguillaris) nuclear rotation occurs, permanence of the cytoplasmic channel, and type and localization of the nuclear fossa. In the G. cf anguillaris spermatozoon the nucleus is spherical with highly condensed chromatin. The nuclear fossa is shallow and lateral and is associated with the centriolar complex through stabilizing fibrils. The midpiece is short, with many vesicles, a cytoplasmic channel, and elongate mitochondria. In the B. cf. pinnicaudatus spermatozoon the ovoid nucleus is elongated lateral and posterior to the centriolar complex, and has highly condensed chromatin. The eccentric nuclear fossa is of the moderate type, and contains the entire centriolar complex. The midpiece is long, with numerous vesicles, elongate mitochondria, and no cytoplasmic channel. In both species the flagella are laterally disposed in relation to the nucleus and comprise of the classical 9 + 2 axoneme. Most of the characteristics found in the spermatozoa of these two species of Gymnotiformes are shared with species of Characiformes, whereas only a few are also found in Siluriformes. This suggests that Gymnotiformes and Characiformes may be more closely related than previously proposed. (C) 2007 Elsevier Ltd. All rights reserved.

Ultrastructure of spermatogenic cells and spermatozoa in Hoplias malabaricus (teleostei, characiformes, erythrinidae)

The differentiation of spermatids in Hoplias malabaricus is characterized by chromatin compaction, flagellum development, nuclear rotation, nuclear fossa formation, and excess cytoplasm elimination. In the resulting spermatozoon, the head is round and the nucleus contains chromatin compacted in thick filaments, peripherically arranged, to a central electron-lucent area. The acrosome is absent. The nuclear fossa is eccentric but not pronounced. The proximal centriole penetrates it and is oblique to the flagellum. The long midpiece has several converging elongate vesicles, forming membranous hoops in the initial segment of the flagellum, but has no cytoplasmic channel. The mitochondria are elongate and branched or C-shaped and located around the initial segment of the axoneme. The lateral flagellum does not show lateral projections. The ultrastructural characteristics of H. malabaricus spermatozoa are similar to the Cypriniformes. (C) 2001 the Fisheries Society of the British Isles.

Spermiogenesis and spermatozoa ultrastructure in Salminus and Brycon, two primitive genera in Characidae (Teleostei : Ostariophysi : Characiformes)

In Salminus, spermiogenesis is cystic and gives origin to a type I aquasperm. Spermatid differentiation is characterized by chromatin condensed into thick fibres, nuclear rotation, nuclear fossa formation, cytoplasmic channel formation, mitochondrial fusion producing long and ramified mitochondria, and the presence of several membranous concentric rings around the plasma membrane that encircles the cytoplasmic channel. In Salminus and Brycon, spermatozoa are very similar. They exhibit a spherical nucleus and chromatin condensed into fibre clusters, and a deep nuclear fossa. They show a long midpiece with few elongate mitochondria at the initial region and a cytoplasmic channel completely encircled by one or two membranous concentric rings. The flagellar axis is perpendicular to the nucleus and exhibits the classic axoneme (9 + 2). The very strong similarity observed between Salminus and Brycon spermatozoa supports the hypothesis that these subfamilies are likely to have a monophyletic origin.

Spermatozoa ultrastructure in Sciaenidae and Polynemidae (Teleostei : Perciformes) with some consideration on Percoidei spermatozoa ultrastructure

Spermatozoa ultrastructure was studied in five marines (Paralonchurus brasiliensis, Larimus breviceps, Cynoscion striatus, Micropogonias furnieri, Menticirrhus americanus, Umbrina coroides, Stellifer rastrifer), and one freshwater (Plagioscion squamosissimus) species of Sciaenidae and one species of Polynemidae (Polydactylus virginicus). The investigation revealed that, in all species, spermatozoa display a round head, a nucleus containing highly condensed, filamentous chromatin clusters, no acrosome, a short midpiece with a short cytoplasmic channel, and a flagellum showing the classic axoneme structure (9 + 2) and short irregular lateral fins. In Sciaenidae, the spermatozoa are type II, the flagellar axis is parallel to the nucleus, the lateral nuclear fossa is double arched, the centriolar complex is outside the nuclear fossa, the proximal centriole is anterior and perpendicular to the distal centriole, and no more than ten spherical (marine species) or elongate (freshwater species) mitochondria are observed. Polynemidae spermatozoa are of the intermediate type with the flagellar axis eccentric to the hemi-arc-shaped nucleus, and exhibit no nuclear fossa, the centriolar complex close to the upper nuclear end, the proximal centriole lateral and oblique to the distal centriole, and one large ring-shaped mitocondrion. The data available show that no characteristic is exclusively found in the spermatozoa of members of the Sciaenidae family when compared to other Percoidei with type II spermatozoa. However, three characteristics were exclusively found in Polynemidae: (1) the hemi-arched nucleus; the positioning of the centrioles; and (2) the ring-shaped mitocondrion. The interrelationships between Sciaenidae and Polynemidae as well as between these two families and other Percoidei are herein discussed. (c) 2005 Elsevier Ltd. All rights reserved.

Spermiogenesis and sperm ultrastructure in Cichla intermedia with some considerations about Labroidei spermatozoa (Teleostei, Perciformes, Cichlidae)

Spermiogenesis and spermatozoal structure were studied in Cichla intermedia, a primitive species of Neotropical cichlids. The analysis shows that spermiogenesis is characterized by chromatin compaction, flagellum development, nuclear rotation, nuclear fossa formation and residual cytoplasm elimination. In the spermatozoa, the head is round, the nucleus contains highly condensed filamentous clusters of chromatin and an acrosome is absent. The nuclear fossa is slightly eccentric and shows a projection that penetrates into the nuclear outline. The proximal centriole is located in the initial segment of the nuclear fossa. The midpiece and the cytoplasmic channel are long. The mitochondria, about 10 in number, are round or slightly elongated, disposed in two layers around the initial segment of the flagellum. The flagellum has a classical 9 + 2 axoneme and two lateral fins. The data available show that no characteristics of spermiogenesis or spermatozoa are exclusively found in members of the suborder Labroidei. However, three characteristics seem to be exclusively observed in Cichlidae: (1) compact filamentous clusters of chromatin; (2) slightly eccentric nuclear fossa; and, (3) number of mitochondria. (C) 2003 Elsevier Ltd. All rights reserved.

The ultrastructure of spermiogenesis and spermatozoa in Diplomystes mesembrinus

Spermiogenesis in Diplomystes mesembrinus, one of the most primitive species from the Siluriformes, occurs in cysts. Differentiation of spermatids is characterized by chromatin compaction, flagellum development, nuclear fossa formation, rotation of the nucleus, and excess cytoplasm elimination. The spermatozoon head is round, the nucleus contains highly condensed chromatin clusters, the midpiece is short, the axoneme shows a 9 + 2 pattern with two discrete lateral projections, and the acrosome is absent. The nuclear fossa penetrates deeply into the nucleus, including the centriolar complex and the start of the axoneme. The single large C-shaped mitochondrion sur rounds the: initial segment of the axoneme. The structural features of D. mesembrinus spermatozoon are similar to the Clupeiformes. (C) 2001 the Fisheries Society of the British Isles.

Spermiogenesis and spermatozoa ultrastructure in five species of the Curimatidae with some considerations on spermatozoal ultrastructure in the Characiformes

A espermiogênese nas espécies Steindachnerina insculpta, Cyphocharax gillii, C. modestus, C. spilotus e Potamorhina altamazonica de Curimatidae é caracterizada pelo desenvolvimento lateral do flagelo, rotação do núcleo, formação excêntrica da fossa nuclear e cromatina compactada em fibras espessas. Estes espermatozóides exibem uma cabeça esférica contendo um núcleo com cromatina altamente condensada em fibras espessas com pequenas áreas eletronlúcidas, e sem acrossoma. A fossa nuclear é do tipo moderado e excêntrico, penetrada pelo complexo centriolar. A peça média é pequena, tem muitas vesículas alongadas e um curto canal citoplasmático. Mitocôndrias podem ser alongadas, ramificadas ou em forma de C, e são separadas do segmento inicial do axonema pelo canal citoplasmático. O flagelo contém a estrutura clássica do axonema (9+2) e tem um compartimento membranoso na região inicial; não possui expansões laterais (fins). Somente pequenas diferenças foram observadas entre as espécies e gêneros analisados de Curimatidae. A espermiogênese e os espermatozóides de Curimatidae têm muitas das características encontradas em quase todas as outras espécies de Characiformes. Por outro lado, a presença de um compartimento membranoso na região inicial do flagelo dos curimatídeos, uma estrutura comum nos espermatozóides de muitos cipriniformes, é desconhecida em outros characiformes. Discute-se sobre a espermiogênese e espermatozóides de Characiformes.

Spermiogenesis and spermatozoa ultrastructure in the Serrasalminae (Ostariophysi: Characiformes) with further evidence on the relationships of the piranhas and pacus

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Fresh-frozen human bone graft for repair of defect after adenomatoid odontogenic tumour removal

The aim of this paper was report the clinical, radiographic, and histological case of adenomatoid odontogenic tumour (AOT) in adolescent woman as well as present the reconstructive treatment of AOT using fresh-frozen human bone graft with guided bone regeneration. AOT is a benign, noninvasive lesion with slow but progressive growth. Biopsy and microscopic examination confirmed the presence of an AOT. Treatment was conservative and the prognosis was excellent. The patient has been followed-up for without recurrence. The use of fresh-frozen human bone graft can be a safe choice for reconstruction of the bone defects to treat AOT.

Momentum-space non-hydrogenic wavefunction of quantum defect theory

We derive a closed-form analytic expression in momentum space for the asymptotic non-hydrogenic wavefunction of the quantum defect theory (QDT) due to Seaton and compare it with a widely used QDT-approximate wavefunction for the Rydberg states Li-3(2s), Mg-24(6s) and Rb-37(5s).

A polaronic stacking fault defect model for CaCu3Ti4O12 material: an approach for the origin of the huge dielectric constant and semiconducting coexistent features

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)