254 resultados para JAWS
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Background: This prospective and controlled histologic study evaluates the impact of smoking on bone-to-implant contact, the bone density in the threaded area, and the bone density outside the threaded area around microimplants with anodized surface retrieved from human jaws. Methods: A total of 24 subjects (mean age 51.32 +/- 7.5 years) were divided in two groups: smokers (n = 13 subjects) and non-smokers (n = 11 subjects). Each subject received one microimplant with oxidized surface during conventional mandible or maxilla implant surgery. After 8 weeks, the microimplants and the surrounding tissue were removed and prepared for histomorphometric analysis. Results: Three microimplants placed in smokers showed no osseointegration. The newly formed bone showed early stages of maturation, mainly in the non-smokers. Marginal bone loss, gap, and fibrous tissue were present around implants retrieved from smokers. Histometric evaluation indicated that the mean bone-to-implant contact ranged between 25.97% +/- 9.02% and 40.01% +/- 12.98% for smokers and non-smokers, respectively (P <0.001). Smokers presented 28.17% +/- 10.32% of bone density in the threaded area, whereas non-smokers showed 46.34% +/- 19.12%. The mean of bone density outside the threaded area ranged between 18.76% and 25.11% for smokers and non-smokers, respectively (P>0.05). Conclusion: The present data obtained in human subjects confirm that smoking has a detrimental effect on early bone tissue response around oxidized implant surfaces. J Periodontol 2010;81:575-583.
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Many lungfish of the tooth plated lineage, both fossil and living, are affected by dental and skeletal pathologies including dental caries, abscesses and cysts within the bone or tooth plate, osteopenia, bone hypertrophy, and malocclusion. These conditions, while influenced in part by structural relationships of soft and hard tissues in the tooth plates, jaw bones and surrounding oral tissues, can also be used as indicators of the kind of environment inhabited by the fish. The disease processes have specific structural consequences, related either to the pathology or to attempts to heal the damage, and usually alter the form and function of the tooth plate or bone. Consequently they can be distinguished from postmortem diagenetic or taphonomic effects, which alter the structure in less specific ways and show no sign of healing. Dental caries, the most common pathological condition in dipnoan dentitions, is recognisable in lungfish from the Devonian of Western Australia, the Tertiary of South Australia and the Northern Territory and from living lungfish in south east Queensland. Other pathologies have a more sporadic occurrence.
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Bisphosphonate related osteonecrosis of the jaw (BRONJ) is defined as exposed necrotic bone appearing in the jaws of patients treated by systemic IV or oral BPs never irradiated in the head and neck area and that has persisted for more than 8 weeks. More than 90% of cases of osteonecrosis of the jaw have been in patients with cancer who received IV-BPs. The estimate of cumulative incidence of BRONJ in cancer patients with IV-BPs ranges from 0.8% to 18.6%. The pathogenesis of BRONJ appeared related to the potent osteoblast-inhibiting properties of BPs which act by blocking osteoclast recruitment, decreasing osteoclast activity and promoting osteoclast apoptosis. Dental extractions are the most potent local risk factor. Cancer patients wearing a denture could also be at increased risk of BRONJ. Non-healing mucosal breaches caused by dentures could be a portal for the oral flora to access bone, while the oral mucosa of patients on IV-BPs could also be defective. Whether periodontal disease is a risk factor for BRONJ remains controversial. Preventive measures are fundamental. Nevertheless, some teams have questioned its cost-effectiveness. The perceived limitations of surgical therapy of BRONJ led to the restriction of aggressive surgery to symptomatic patients with stage 3 BRONJ. The evidence-based literature on BRONJ is growing but there are still many controversial aspects.
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Purpose – The purpose of this paper is to demonstrate key strategic decisions involved in turning around a large multinational operating in a dynamic market. Design/methodology/approach – The paper is based on analysis of archival documents and a semi-structured interview with the chairman of the company credited with its rescue. Findings – Turnaround is complex and involves both planned and emergent strategies. The progress is non-linear requiring adjustment and change in direction of travel. Top management credibility and vision is critical to success. Rescue is only possible if the company has a strong cash generative business among its businesses. The speed of decision making, decisiveness and the ability to implement strategy are among the key ingredients of success. Originality/value – Turnaround is an under-researched area in strategy. This paper contributes to a better understanding in this important area and bridges the gap between theory and practice. It provides a practical view and demonstrates how a leading executive with significant expertise and successful turnaround track record deals with inherent dilemmas of turnaround
Resumo:
Background: This prospective and controlled histologic study evaluates the impact of smoking on bone-to-implant contact, the bone density in the threaded area, and the bone density outside the threaded area around microimplants with anodized surface retrieved from human jaws.Methods: A total of 24 subjects (mean age 51.32 +/- 7.5 years) were divided in two groups: smokers (n = 13 subjects) and non-smokers (n = 11 subjects). Each subject received one microimplant with oxidized surface during conventional mandible or maxilla implant surgery. After 8 weeks, the microimplants and the surrounding tissue were removed and prepared for histomorphometric analysis.Results: Three microimplants placed in smokers showed no osseointegration. The newly formed bone showed early stages of maturation, mainly in the non-smokers. Marginal bone loss, gap, and fibrous tissue were present around implants retrieved from smokers. Histometric evaluation indicated that the mean bone-to-implant contact ranged between 25.97% +/- 9.02% and 40.01% +/- 12.98% for smokers and non-smokers, respectively (P <0.001). Smokers presented 28.17% +/- 10.32% of bone density in the threaded area, whereas non-smokers showed 46.34% +/- 19.12%. The mean of bone density outside the threaded area ranged between 18.76% and 25.11% for smokers and non-smokers, respectively (P>0.05).Conclusion: The present data obtained in human subjects confirm that smoking has a detrimental effect on early bone tissue response around oxidized implant surfaces. J Periodontol 2010;81:575-583.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The purpose of this study was to evaluate the influence of the oxidized surface on bone-to-implant contact (BIC%), the bone density in the threaded area (BA %), as well as the bone density outside the threaded area (BD%) in human jaws after 2 months of unloaded healing. Thirteen subjects (mean age 42.61 +/- 6.15 years) received two microimplants (2.5 mm diameter and 6 mm length) each, during conventional mandible or maxilla implant surgery. The microimplants with commercially pure titanium surfaces (machined) and oxidized surfaces served as the control and test surfaces, respectively. After 2 months, the microimplants and the surrounding tissue were removed and prepared for histomorphometric analysis. All microimplants, except two machined and one oxidized microimplant surfaces, were found to be clinically stable after the healing period. Histometric evaluation indicated that the mean BIC % was (21.71 +/- 13.11) % and (39.04 +/- 15.75) % for machined and oxidized microimplant surfaces, respectively. The BD% was higher for the oxidized surface, although there was no difference for maxilla and mandible. The oxidized surface impacted the BA% for the type-IV bone. Data suggest that the oxidized surface presented a higher bone-to-implant contact rate compared with machined surfaces under unloaded conditions, after a healing period of 2 months. (c) 2006 Wiley Periodicals, Inc.
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Bisphosphonate-related osteonecrosis of the jaws is a relevant side-effect of these drugs that has been generating a great concern through increasing reports, worldwide, of this bone necrosis. Among several BRONJ hypothetical co-factors that could play a role in BRONJ pathogenesis, rheumatoid arthritis (RA) has been included as a relevant risk factor for BRONJ; however, until now the relationship between these diseases has not been fully explained. Thus, the purpose of this paper is to establish hypothetical factors that could link these two diseases, considering mainly inflammatory components and the organism effects of medicines used to treat RA, particularly steroids and methotrexate (MTX). (C) 2011 Elsevier Ltd. All rights reserved.
Resumo:
Background: Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a clinical condition characterized by the presence of exposed bone in the maxillofacial region. Its pathogenesis is still undetermined, but may be associated with risk factors such as rheumatoid arthritis (RA). The aim of this paper is to report two unpublished cases of BRONJ in patients with RA and to conduct a literature review of similar clinical cases with a view to describe the main issues concerning these patients, including demographic characteristics and therapeutic approaches applied.Methods: Two case reports of BRONJ involving RA patients were discussedResults: Both patients were aging female taking alendronate for more than 3 years. Lesions were detected in stage II in posterior mandible with no clear trigger agent. The treatment applied consisted of antibiotics, oral rinses with chlorhexidine, drug discontinuation and surgical procedures. Complete healing of the lesions was achieved.Conclusions: This paper brings to light the necessity for rheumatologists to be aware of the potential risk to their patients of developing BRONJ and to work together with dentists for the prevention and early detection of the lesions. Although some features seem to link RA with oral BRONJ and act as synergistic effects, more studies should be developed to support the scientific bases for this hypothesis.
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This literature review aims to evaluate the epidemiologic profile of patients with rheumatoid arthritis (RA) that developed a bisphosphonate-related osteonecrosis that affect the jaws (BRONJ), including demographic aspects, as well as clinical and therapeutic issues. A search of PUBMED/MEDLINE, Scopus, and Cochrane databases from January 2003 to September 2011 was conducted with the objective of identifying publications that contained case reports regarding oral BRONJ in RA patients. Patients with RA who develop oral BRONJ are usually women above 60 years taking steroids and long-term alendronate. Most of them have osteoporosis, and lesions, triggered by dental procedures, are usually detected at stage II in the mandible. Although there is no accepted treatment protocol, these patients seem to have better outcomes with conservative approaches that include antibiotic therapy, chlorhexidine, and drug discontinuation.
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Bisphosphonates are compounds used in the treatment of various metabolic and malignant bone diseases. The relation between the use of bisphosphonates and ostenonecrosis of the jaws as an adverse effect of the drug has been intensely discussed during the last few years, and up to this moment, there is no consensus concerning an ideal treatment modality for this condition. Nevertheless, there is an agreement among researchers that the standard goal for controlling jaw osteonecrosis is to prevent it. Otherwise, the rationale for a randomized controlled trial is that current treatment has proven to be suboptimal, and no consensus has been reached yet on the best strategies to repair the exposed bone once bone necrosis is developed. This article is focused on reporting a case of moderate osteonecrosis of the upper jaw induced by bisphosphonates and discusses a possible role for surgical debridement associated to platelet-rich plasma, hyperbaric oxygen therapy, and the cessation of the bisphosphonate use in managing this type of lesion. Moreover, the dentist, the oral surgeon, and the oncologist need to work together to reach better outcomes.
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Osteopetrosis is a rare hereditary condition characterized by increased bone density. The jaws, bones, and teeth invariably are affected and the osteopetrosis is directly proportional with the severity of the disease. This article describes a clinical case of osteopetrosis and reviews the clinicopathologic, radiographic, and treatment features.
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Osteonecrosis of the jaw (ONJ) following the use of bisphosphonates has become of increased interest in the scientific community, due in particular to its as-yet-unsolved pathogenesis. An experimental model of ONJ was induced in normal male rats [alendronate (ALN); 1 mg/Kg/day; n = 10] and matched controls (saline solution; n = 10). After 60 days of drug treatment, all animals were subjected to extractions of the left first lower molars and were euthanized at 3 and 28 days postsurgery. The following analyses were performed: (i) descriptive and quantitative (scores) histological evaluation, (ii) stereometry of distal sockets and (iii) biochemical measurement of C-telopeptide cross-linked collagen type I (CTX) and bone-specific alkaline phosphatase (BALP). The results showed that 28 days postsurgery the animals treated with ALN had areas of exposed and necrotic bone, associated with significant infection, especially in the interalveolar septum area and crestal regions, compared with controls. The levels of CTX, BALP and bone volume, as well as the degrees of inflammation and vascularization, were significantly reduced in these animals. Therefore, analysis of the data presented suggests that ALN therapy is associated with the development of osteonecrosis in the jaws of rodents after tooth extraction. © 2012 International Journal of Experimental Pathology.