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Síndrome da Imunodeficiência Adquirida , Leucoencefalopatia Multifocal Progressiva , Humanos , Leucoencefalopatia Multifocal Progressiva/diagnóstico , Masculino , Síndrome da Imunodeficiência Adquirida/complicações , Hospedeiro Imunocomprometido , Imageamento por Ressonância Magnética , Diagnóstico Diferencial , Vírus JC/isolamento & purificação , Adulto , Infecções Oportunistas Relacionadas com a AIDS/diagnósticoRESUMO
PURPOSE: Waste collection is considered particularly heavy work, although no previous study has yet investigated the strain of bulk waste collection. The aim of this study is to determine the workload of bulk waste workers in practice. METHOD: We conducted a cross-sectional field-study. Fourteen male volunteers from the bulk waste collection of the municipal sanitation department in Hamburg, Germany, were included. Performance was determined by cardiopulmonary exercise testing under laboratory conditions. During the shift, each worker was accompanied by a researcher, and heart rate (HR) was recorded under field conditions using an HR watch with a belt system. We examined mean HR, relative heart rate (RHR), relative aerobic strain (RAS), calculated oxygen uptake ([Formula: see text]) and individual ventilatory threshold 1 (VT1) as parameters of workload during their daily work. RESULTS: During the shift, HR was scaled: 102 bpm (SD 10.2), RHR: 36.9%, [Formula: see text]: 1267 ml/min (SD 161), RAS: 49.4% (SD 9.3), and [Formula: see text] in relation to VT1: 75% (SD 18.5). There was no significant difference between oxygen consumption during the main task of lifting and carrying bulky waste and the individual [Formula: see text] at VT1. CONCLUSION: Although the burden of the main task of lifting and carrying bulky waste is very high (at VT1 for more than 3 h), interruptions from other tasks or formal breaks spread the burden over the entire shift. The total workload exceeded most recommendations in the literature across the different work periods. However, the total burden remains below VT1, the only parameter that takes individual endurance performance into account. We recommend again VT1 as an individual upper limit for prolonged occupational work.
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Light-at-night triggers the decline of pineal gland melatonin biosynthesis and secretion and is an IARC-classified probable breast-cancer risk factor. We applied a large-scale molecular epidemiology approach to shed light on the putative role of melatonin in breast cancer. We investigated associations between breast-cancer risk and polymorphisms at genes of melatonin biosynthesis/signaling using a study population of 44,405 women from the Breast Cancer Association Consortium (22,992 cases, 21,413 population-based controls). Genotype data of 97 candidate single nucleotide polymorphisms (SNPs) at 18 defined gene regions were investigated for breast-cancer risk effects. We calculated adjusted odds ratios (ORs) and 95% confidence intervals (CI) by logistic regression for the main-effect analysis as well as stratified analyses by estrogen- and progesterone-receptor (ER, PR) status. SNP-SNP interactions were analyzed via a two-step procedure based on logic regression. The Bayesian false-discovery probability (BFDP) was used for all analyses to account for multiple testing. Noteworthy associations (BFDP < 0.8) included 10 linked SNPs in tryptophan hydroxylase 2 (TPH2) (e.g. rs1386492: OR = 1.07, 95% CI 1.02-1.12), and a SNP in the mitogen-activated protein kinase 8 (MAPK8) (rs10857561: OR = 1.11, 95% CI 1.04-1.18). The SNP-SNP interaction analysis revealed noteworthy interaction terms with TPH2- and MAPK-related SNPs (e.g. rs1386483R ⧠rs1473473D ⧠rs3729931D: OR = 1.20, 95% CI 1.09-1.32). In line with the light-at-night hypothesis that links shift work with elevated breast-cancer risks our results point to SNPs in TPH2 and MAPK-genes that may impact the intricate network of circadian regulation.
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Neoplasias da Mama , Melatonina , Humanos , Feminino , Neoplasias da Mama/genética , Neoplasias da Mama/epidemiologia , Melatonina/genética , Melatonina/metabolismo , Teorema de Bayes , Polimorfismo de Nucleotídeo Único , Modelos Logísticos , Estudos de Casos e Controles , Predisposição Genética para DoençaRESUMO
OBJECTIVE: The aim of this study is to investigate whether there is an association between brief but repeated exposures to extremely cold temperatures over many years and pulmonary function. METHODS: We performed a retrospective analysis of the data collected over 10 years in the context of the extended medical examinations of storeworkers exposed to extremely cold temperatures. We considered forced vital capacity (FVC), forced expiratory volume in one second (FEV1), Tiffeneau-Pinelli index (FEV1/FVC), CO diffusion capacity (DL,CO) and Krogh-factor (CO diffusion capacity relative to recorded alveolar volume, DL,CO/VA) reported as %-predicted. We analysed trends in outcome parameters with linear mixed models. RESULTS: 46 male workers participated in at least two extended medical examinations between 2007 and 2017. Overall 398 measure points were available. All lung function parameters had values above the lower limit of normality at the first examination. In the multivariate model including smoking status and monthly intensity of cold exposure (≤ 16 h/month vs. > 16 h/month) FEV1%-predicted and FVC %-predicted had a statistically significant positive slope (FEV1, 0.32% 95% CI 0.16% to 0.49% p < 0.001; FVC 0.43% 95% CI 0.28% to 0.57% p < 0.001). The other lung function parameters (FEV1/FVC %-predicted, DL,CO %-predicted, DL,CO/VA %-predicted) showed no statistically significant change over time. CONCLUSIONS: Long term intermittent occupational exposure to extreme cold temperatures (-55 °C) does not appear to cause irreversible deleterious changes in lung function in healthy workers, thus the development of obstructive or restrictive lung diseases is not expected.
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Pulmão , Humanos , Masculino , Seguimentos , Estudos Retrospectivos , Capacidade Vital , Volume Expiratório ForçadoRESUMO
Healthcare workers bear a high risk of infection during epidemics and pandemics such as the current SARS-CoV-2 pandemic. Various new vaccines have been approved. We investigated the influence of the time elapsed since vaccination, as well as of vaccination schema, on health workers' spike antibody levels following their second vaccination. Blood samples were obtained from employees working at a German hospital between August 2021 and December 2021 on average half a year (range 130-280 days) after their second vaccination. Levels of SARS-CoV-2-IgG antibodies (spike and nucleocapsid protein) were qualitatively detected via chemiluminescent immunoassays (CLIAs). A previous infection with SARS-CoV-2 was an exclusion criterion. In total, 545 persons were included in this cross-sectional study. Most participants (97.8%) showed elevated anti-spike concentrations. Anti-spike levels differed significantly among vaccination schemas. Repeated vector vaccinations resulted in lower protective antibody levels. Higher age levels, immunosuppression and a longer time period since the second vaccination resulted in lower anti-spike levels. Women's antibody levels were higher, but not significantly. Since anti-spike levels drop after vaccination, further boosters are required to increase immunoreactivity. If two vector vaccines have been administered, it is possible that an mRNA booster might increase the anti-spike level.
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COVID-19 , Glicoproteína da Espícula de Coronavírus , Anticorpos Antivirais , COVID-19/prevenção & controle , Estudos Transversais , Feminino , Pessoal de Saúde , Humanos , Imunoglobulina G , Proteínas do Nucleocapsídeo , RNA Mensageiro , SARS-CoV-2 , Vacinação , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/metabolismoRESUMO
BACKGROUND: Even almost 30 years after the ban on the use of asbestos in Germany, the effects of asbestos are still highly relevant in everyday clinical practice in occupational medicine. The aim of this study was to further investigate the significance of essential parameters of both pulmonary function diagnostics and imaging techniques (low-dose HR-TCT) for the prevention and early detection of asbestos-related morphological and functional lung changes. METHODS: Data from spirometry, body plethysmography and diffusion capacity, as well as CT images of the thorax, were retrospectively studied from 72 patients examined between 2017 and 2019 at the Institute for Occupational and Maritime Medicine (ZfAM), Hamburg, Germany. The subjects were divided into four subgroups according to the presence of comorbidities (concomitant cardiac diseases, obstructive ventilatory disorder, pulmonary function pattern consistent with emphysema, and no other pulmonary or cardiac diseases). These subgroups were analysed in addition to the overall collective. The CT images were evaluated according to the International Classification of Occupational and Environmental Respiratory Diseases (ICOERD) with radiological expertise. In addition, some asbestos-related parameters were newly quantified, and corresponding scores were defined based on ICOERD. Statistical analysis included the use of correlations and fourfold tables with calculation of Spearman's rho (ρ), Cohen's κ, and accuracy. RESULTS: Vital capacity (VC) is slightly reduced in the total collective compared to the normal population (mean 92% of predicted value), while diffusion capacity for CO (DLCO) shows predominantly pathological values, mean 70% of the respective predicted value. The CO transfer coefficient (DLCO/VA), which refers to alveolar volume (VA), also shows slightly decreased values (mean 87% pred.). Seventy-nine percent of patients (n = 57) had signs of pulmonary fibrosis on CT scans, and pleural plaques appeared in 58 of 72 patients (81%). Of the newly quantified additional parameters, particularly frequently described findings are subpleural curvilinear lines (SC, n = 39) and parenchymal bands (PB, n = 29). VC correlates well with the expression of pleural plaques (ρ = - 0.273, P < 0.05), and DLCO measures show a better correlation with fibrosis score (ρ = - 0.315, P < 0.01). A third, newly developed score, which includes the extent of pleural plaques and additional subpleural parameters instead of fibrosis parameters, shows significant correlations for both VC and DLCO (ρ = - 0.283, - 0.274, resp.; both P < 0.05). DISCUSSION: The importance of spirometry (VC) and diffusion capacity measurement (DLCO) as essential diagnostic procedures for the early detection of asbestos-related changes â also including patients with relevant concomitant cardiac or pulmonary diseases â was confirmed. Significant and better correlations between lung function changes (VC and DLCO) and abnormal CT findings are seen when parenchymal bands (PB), subpleural curvilinear lines (SC), and rounded atelectasis (RA) are quantitatively included into the evaluation, in addition to assessing the extent of pleural plaques alone. Therefore, when assessing CT images according to ICOERD, these parameters should also be quantified.
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Amianto , Asbestose , Cardiopatias , Doenças Pleurais , Fibrose Pulmonar , Amianto/efeitos adversos , Asbestose/diagnóstico , Humanos , Pulmão/diagnóstico por imagem , Estudos Retrospectivos , Tomografia Computadorizada por Raios X , Capacidade VitalRESUMO
INTRODUCTION: Schneiderian membrane perforation (SMP), which is usually readily manageable, is the most common intraoperative complication of sinus elevation surgery. Some evidence suggests that SMP is associated with increased risk for postoperative complications, including maxillary sinusitis. Antral wall discontinuity (AWD) is an acquired condition that may increase SMP likelihood and lead to larger, less-manageable perforations. CASE PRESENTATION: A generally healthy patient receiving sinus elevation surgery exhibited an AWD in the palatine process of the maxilla. The osseous defect was isolated intraoperatively, and the Schneiderian membrane was sharply dissected from the palatal connective tissue. Favorable augmentation of the maxillary sinus was noted on cone-beam computed tomography (CBCT) assessment at postoperative month 34. CONCLUSIONS: AWD (fusion of the Schneiderian membrane with the periosteum of the maxilla) is a condition identifiable on preoperative CBCT images, which may increase the incidence and severity of SMP during sinus elevation procedures. Careful assessment for integrity of antral osseous walls before surgery is essential. Presence of AWD may obligate modifications to the surgical plan, or in some cases, contraindicate sinus elevation surgery.
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Sinusite Maxilar , Levantamento do Assoalho do Seio Maxilar , Tomografia Computadorizada de Feixe Cônico , Humanos , Maxila , Seio Maxilar/diagnóstico por imagem , Seio Maxilar/cirurgiaRESUMO
BACKGROUND: Asbestos-related lung diseases are one of the leading diagnoses of the recognized occupational diseases in Germany, both in terms of their number and their socio-economic costs. The aim of this study was to determine whether pulmonary function testing (spirometry and CO diffusion measurement (DLCO)) and computed tomography of the thorax (TCT) are relevant for the early detection of asbestos-related pleural and pulmonary fibrosis and the assessment of the functional deficiency. METHODS: The records of 111 formerly asbestos-exposed workers who had been examined at the Institute for Occupational and Maritime Medicine, Hamburg, Germany, with data on spirometry, DLCO and TCT were reviewed. Workers with substantial comorbidities (cardiac, malignant, silicosis) and/or pulmonary emphysema (pulmonary hyperinflation and/or TCT findings), which, like asbestosis, can lead to a diffusion disorder were excluded. The remaining data of 41 male workers (mean 69.8 years ±6.9) were evaluated. The TCT changes were coded according to the International Classification of High-resolution Computed Tomography for Occupational and Environmental Respiratory Diseases (ICOERD) by radiologists and ICOERD-scores for pleural and pulmonary changes were determined. Correlations (ρ), Cohens κ and accuracy were calculated. RESULTS: In all 41 males the vital capacity (VC in % of the predicted value (% pred.)) showed only minor limitations (mean 96.5 ± 18.0%). The DLCO (in % pred.) was slightly reduced (mean 76.4 ± 16.6%; median 80.1%); the alveolar volume related value (DLCO/VA) was within reference value (mean 102 ± 22%). In the TCT of 27 workers pleural asbestos-related findings were diagnosed whereof 24 were classified as pulmonary fibrosis (only one case with honey-combing). Statistical analysis provided low correlations of VC (ρ = - 0.12) and moderate correlations of DLCO (- 0.25) with pleural plaque extension. The ICOERD-score for pulmonary fibrosis correlated low with VC (0.10) and moderate with DLCO (- 0.23); DLCO had the highest accuracy with 73.2% and Cohens κ with 0.45. DLCO/VA showed no correlations to the ICOERD-score. The newly developed score, which takes into account the diffuse pleural thickening, shows a moderate correlation with the DLCO (ρ = - 0.35, p < 0.05). CONCLUSIONS: In formerly asbestos-exposed workers, lung function alterations and TCT findings correlated moderate, but significant using DLCO and ICOERD-score considering parenchymal ligaments, subpleural curvilinear lines, round atelectases and pleural effusion in addition to pleural plaque extension. DLCO also showed highest accuracy in regard to pulmonary findings. However, VC showed only weaker correlations although being well established for early detection. Besides TCT the determination of both lung function parameters (VC and DLCO) is mandatory for the early detection and assessment of functional deficiencies in workers formerly exposed to asbestos.
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BACKGROUND: Previous predictions of population morbidity consider demographic changes only. To model future morbidity, however, changes in prevalences of risk factors should be considered. We calculated the number of incident cases of first myocardial infarction (MI) in Mecklenburg-Western Pomerania in 2017 considering the effects of demographic changes and trends in the prevalences of major risk factors simultaneously. METHODS: Data basis of the analysis were two population-based cohorts of the German Study of Health in Pomerania (SHIP-baseline [1997-2001] and the 5-year follow-up and SHIP-Trend-baseline [2008-2011] respectively). SHIP-baseline data were used to calculate the initial coefficients for major risk factors for MI with a Poisson regression model. The dependent variable was the number of incident cases of MI between SHIP-baseline and SHIP-5-year follow-up. Explanatory variables were sex, age, a validated diagnosis of hypertension and/or diabetes, smoking, waist circumference (WC), increased blood levels of triglycerides (TG) and low-density-lipoprotein cholesterol (LDL), and low blood levels of high-density-lipoprotein cholesterol (HDL). Applying the coefficients determined for SHIP baseline to risk factor prevalences, derived from the new cohort SHIP-Trend together with population forecast data, we calculated the projected number of incident cases of MI in 2017. RESULTS: Except for WC and smoking in females, prevalences of risk factors in SHIP-Trend-baseline were lower compared to SHIP-baseline. Based on demographic changes only, the calculated incidence of MI for 2017 compared to the reference year 2006 yields an increase of MI (males: +11.5%, females: +8.0%). However, a decrease of MI (males: -23.7%, females: -17.1%) is shown considering the changes in the prevalences of risk factors in the projection. CONCLUSIONS: The predicted number of incident cases of MI shows large differences between models with and without considering changes in the prevalences of major risk factors. Hence, the prediction of incident MI should preferably not only be based on demographic changes.
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Infarto do Miocárdio/epidemiologia , Feminino , Alemanha/epidemiologia , Humanos , Incidência , Masculino , Prevalência , Fatores de RiscoRESUMO
Pyogenic granuloma is a benign nodular lesion occurring most commonly on the gingiva of females during periods of elevated sex hormones such as puberty and pregnancy. Possible molecular mechanisms responsible for the appearance of pyogenic granuloma in this demographic have been suggested. Increased incidence of pyogenic granuloma in post menopausal women on hormone replacement therapy has not been reported. A 49-year-old woman with preexisting titanium implant placement in the left posterior mandible presented with complaint of food impaction and slight discomfort associated with the implant. Clinical examination revealed slight soft tissue erythema and edema, but no foreign body could be identified. Subsequently, a nodular gingival lesion associated with the implant developed and was treated by conservative surgical excision. Histologic characteristics of the lesion were consistent with pyogenic granuloma. The patient was informed of the diagnosis. No evidence of recurrence could be identified after 6 months. Like peripubertal and pregnant women, postmenopausal women treated with hormone replacement therapy may be at increased risk for pyogenic granuloma. Observational studies designed to establish an association between hormone replacement therapy and pyogenic granuloma have not been conducted. Dentists should be aware of putative pathophysiologic mechanisms for pyogenic granuloma formation and the possibility that hormone replacement may trigger these mechanisms.
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Implantes Dentários/efeitos adversos , Terapia de Reposição de Estrogênios/efeitos adversos , Doenças da Gengiva/etiologia , Granuloma Piogênico/etiologia , Osteoporose Pós-Menopausa/prevenção & controle , Diagnóstico Diferencial , Estrogênios Conjugados (USP)/efeitos adversos , Feminino , Doenças da Gengiva/patologia , Granuloma Piogênico/patologia , Humanos , Mandíbula , Pessoa de Meia-IdadeRESUMO
AIM: The objective of this study was to evaluate the effect of a novel recombinant human GDF-5 (rhGDF-5) construct intended for onlay and inlay indications on periodontal wound healing/regeneration. METHODS: Contralateral, surgically created, critical-size, 6-mm, supra-alveolar periodontal defects in five adult Hound Labrador mongrel dogs received rhGDF-5 coated onto beta-tricalcium phosphate (beta-TCP) particles and immersed in a bioresorbable poly(lactic-co-glycolic acid) (PLGA) composite or the beta-TCP/PLGA carrier alone (control). The rhGDF-5 and control constructs were moulded around the teeth and allowed to set. The gingival flaps were then advanced; flap margins were adapted 3-4 mm coronal to the teeth and sutured. The animals were euthanized at 8 weeks post-surgery when block biopsies were collected for histometric analysis. RESULTS: Healing was generally uneventful. A few sites exhibited minor exposures. Three control sites and one rhGDF-5 site (in separate animals) experienced more extensive wound dehiscencies. The rhGDF-5 and control constructs were easy to apply and exhibited adequate structural integrity to support the mucoperiosteal flaps in this challenging onlay model. Limited residual beta-TCP particles were observed at 8 weeks for both rhGDF-5/beta-TCP/PLGA and beta-TCP/PLGA control sites. The rhGDF-5/beta-TCP/PLGA sites showed significantly greater cementum (2.34 +/- 0.44 versus 1.13 +/- 0.25 mm, p=0.02) and bone (2.92 +/- 0.66 versus 1.21 +/- 0.30 mm, p=0.02) formation compared with the carrier control. Limited ankylosis was observed in four of five rhGDF-5/beta-TCP/PLGA sites but not in control sites. CONCLUSIONS: Within the limitations of this study, the results suggest that rhGDF-5 is a promising candidate technology in support of periodontal wound healing/regeneration. Carrier and rhGDF-5 dose optimization are necessary before further advancement of the technology towards clinical evaluation.
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Implantes Absorvíveis , Cementogênese/efeitos dos fármacos , Portadores de Fármacos , Fator 5 de Diferenciação de Crescimento/administração & dosagem , Periodonto/cirurgia , Regeneração/efeitos dos fármacos , Animais , Regeneração Óssea/efeitos dos fármacos , Fosfatos de Cálcio , Cães , Humanos , Masculino , Ligamento Periodontal/fisiologia , Poliésteres , Proteínas Recombinantes , Cicatrização/efeitos dos fármacosRESUMO
OBJECTIVE: The objective of this study was to evaluate local bone formation following systemic administration of parathyroid hormone (1-34) (PTH), a surgically implanted synthetic beta-tricalcium phosphate (beta-TCP) bone biomaterial serving as a matrix to support new bone formation. MATERIALS AND METHODS: Critical-size, 8 mm, calvarial through-and-through osteotomy defects were surgically created in 100 adult male Sprague-Dawley rats. The animals were randomized into five groups of 20 animals each to receive one of the following treatments: PTH (15 microg PTH/kg/day; subcutaneously), PTH/beta-TCP, beta-TCP, or particulate human demineralized freeze-dried bone (DFDB), and sham-surgery controls. Ten animals/group were euthanized at 4 and 8 weeks post-surgery for radiographic and histometric analysis. RESULTS: The histometric analysis showed that systemic PTH significantly enhanced local bone formation, bone fill averaging (+/-SE) 32.2+/-4.0% compared with PTH/beta-TCP (15.7+/-2.4%), beta-TCP (12.5+/-2.3%), DFDB (14.5+/-2.3%), and sham-surgery control (10.0+/-1.5%) at 4 weeks (p<0.014). Systemic PTH showed significantly enhanced bone formation (41.5+/-4.0%) compared with PTH/beta-TCP (22.4+/-3.0%), beta-TCP (21.3+/-4.4%), and with the sham-surgery control (23.8+/-4.2%) at 8 weeks (p<0.025). The DFDB group showed significantly increased bone formation from 4 (14.5+/-2.3%) to 8 weeks (32.0+/-3.2%) (p<0.006). The PTH/beta-TCP and beta-TCP groups both showed limited biomaterials resorption. The radiographic analysis was not diagnostic to distinguish local bone formation from the radiopaque beta-TCP biomaterial. CONCLUSIONS: Systemic administration of PTH significantly stimulates local bone formation. Bone formation was significantly limited by the beta-TCP biomaterial.
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Conservadores da Densidade Óssea/farmacologia , Regeneração Óssea/efeitos dos fármacos , Hormônio Paratireóideo/farmacologia , Animais , Conservadores da Densidade Óssea/administração & dosagem , Matriz Óssea/transplante , Fosfatos de Cálcio/farmacologia , Injeções , Masculino , Hormônio Paratireóideo/administração & dosagem , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Crânio/cirurgiaRESUMO
BACKGROUND: Cigarette smoking can adversely affect the results of many periodontal procedures. The purpose of this study was to determine whether cigarette smoking affects wound healing of subepithelial connective tissue grafts. METHODS: Seventeen systemically healthy patients with 22 Miller Class I or II mucogingival defects were divided into a non-smoker group or smoker group. Patients were regarded as smokers if they reported smoking 10 to 20 cigarettes per day. The following parameters were documented at the surgery date and 3 and 6 months postoperatively: recession depth (RD), recession width (RW), keratinized gingiva height measured apico-coronally (KG), relative attachment level (RAL), probing depths (PD), bleeding on probing (BOP), and the full-mouth plaque score (FMP). Salivary cotinine samples were taken at the surgery to confirm the smoking history and to quantify cigarette use. RESULTS: Non-smokers (0- to 10-ng/ml cotinine level) healed with statistically more recession coverage than the smokers (>10-ng/ml cotinine level) (98.3% versus 82.3%, respectively; P=0.001). Six months postoperatively, the non-smokers healed with a 0.2-mm mean recession depth compared to a 1.0-mm mean recession depth for the smokers. This difference in recession depth was statistically significant (P=0.014). CONCLUSIONS: Root coverage with connective tissue grafts appears to be negatively associated with cigarette smoking. Smokers should consider smoking cessation or reducing the use of cigarettes for optimal results with connective tissue grafts.
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Tecido Conjuntivo/transplante , Gengiva/transplante , Retração Gengival/cirurgia , Fumar/efeitos adversos , Cicatrização , Adulto , Cotinina/análise , Feminino , Gengivoplastia/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Índice Periodontal , Estudos Prospectivos , Saliva/químicaRESUMO
BACKGROUND: Demineralized freeze-dried bone allograft (DFDBA) is widely used in periodontal therapy as a scaffold for new bone formation in periodontal defects. It is demineralized, theoretically, to expose osteoinductive or osteoconductive bone matrix proteins that should facilitate osteogenesis. The degree of DFDBA demineralization varies between tissue banks and may affect clinical regeneration. A 2% residual calcium level in DFDBA has been shown to result in the highest alkaline phosphatase activity levels in cultured human periosteal cells and is optimally osteoinductive or osteoconductive for new bone formation. The purpose of this study was to evaluate the effect of 4 different residual calcium levels in commercially available DFDBA samples on porcine osteoclast activity as measured by resorption on calcium phosphate-coated disks. METHODS: Bone marrow was harvested from the femurs of 3-week-old farm pigs and cultured for 3 weeks. Hematopoietic stem cells were allowed to differentiate into mature active polykaryons displaying genuine osteoclast characteristics. The osteoclast cells displayed a dense actin band inside the margins of the cytoplasm under light microscopy. Culture media was decanted and collagenase added to free the attached cells. Equal cell samples were pipetted onto calcium phosphate-coated disks in 24-well plates. DFDBA samples with 1.44%, 2.41%, and 5.29% residual calcium; FDBA (30% residual calcium); and control cultures without allograft samples were prepared and all samples incubated for 1 week. Cells were fixed and stained for tartrate-resistant acid phosphatase (TRAP), Oregon Green 488-phalloidin, a stain for cytoskeletal proteins, and counterstained with propidium iodide. Specimens were examined by light and fluorescence microscopy using epi-illumination. Calcium phosphate disks were then rinsed in 5% sodium hypochlorite to remove adherent osteoclasts, and substrate surface changes were measured by white light interferometry and image analysis. RESULTS: A higher yield of TRAP-positive cells was produced without DFDBA; however, resorptive activity appears to be significantly increased in the presence of 2.41% residual calcium as compared to all other experimental groups (P<0.0065). CONCLUSION: In this in vitro model, porcine osteoclasts show significantly more resorptive activity as measured on calcium phosphate-coated disks in the presence of 2.41% residual calcium in DFDBA than in other DFDBA residual calcium levels.