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1.
Wien Klin Wochenschr ; 132(1-2): 19-26, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31912287

RESUMO

BACKGROUND: Patients with hepatic cirrhosis are at increased risk of bone loss. Recent work on areal bone mineral density has reported contradictory findings. As the assessment of bone microarchitecture is complex, a search was made for correlations with new serum markers of bone turnover. Current data on serum sclerostin levels in patients with increased fracture risk are divergent and to date only one study has examined patients with hepatic cirrhosis. Therefore, the aim of this study was to evaluate serum sclerostin levels and to test for correlations with microarchitecture. METHODS: This study was performed in 32 patients with recently diagnosed hepatic cirrhosis and 32 controls. The parameters of bone microarchitecture were assessed by high-resolution peripheral quantitative computed tomography. Sclerostin was detected via a new ELISA that detects the active receptor interaction site at loop 2 of the sclerostin core region. RESULTS: Sclerostin levels were slightly, but not significantly lower in the patient group, compared to controls. In contrast, patients with alcoholic liver cirrhosis had significantly lower levels than the controls. A significant correlation with areal bone mineral density (BMD) and trabecular microarchitecture was observed in the patient group. However, there was hardly any correlation between sclerostin and bone microarchitecture in the controls. CONCLUSION: In hepatic cirrhosis, sclerostin is related to altered bone microarchitecture and lower areal BMD. In alcoholic liver disease, low sclerostin concentrations were seen.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Biomarcadores , Densidade Óssea , Remodelação Óssea , Cirrose Hepática , Proteínas Adaptadoras de Transdução de Sinal/sangue , Biomarcadores/sangue , Proteínas Morfogenéticas Ósseas , Humanos , Cirrose Hepática/sangue , Cirrose Hepática/complicações
2.
Rev Med Suisse ; 16(676-7): 78-80, 2020 Jan 15.
Artigo em Francês | MEDLINE | ID: mdl-31961090

RESUMO

Except for bisphosphonates, the duration of anti-osteoporotic treatment is not limited to 3 to 5 years. T-score between - 2.0 and - 1.5 DS might be the BMD target to reach before considering discontinuing anti-osteoporosis treatment. A rebound of bone remodeling can occur in some patients despite receiving zoledronate after denosumab discontinuation, and the monitoring of CTX is required. There is no benefit of vitamin D supplementation on musculoskeletal health in the general population, but vitamin D remains indicated in patients with vitamin D deficiency or receiving osteoporosis treatment. A sequential treatment with romosozumab during one year, a bone anabolic anti-sclerostin antibody, followed by two years of denosumab, decreases vertebral and non-vertebral fractures with rapid and substantial BMD gains after 3 years.


Assuntos
Conservadores da Densidade Óssea , Remodelação Óssea , Osteoporose Pós-Menopausa , Osteoporose , Densidade Óssea , Conservadores da Densidade Óssea/uso terapêutico , Osso e Ossos , Denosumab , Difosfonatos , Humanos , Osteoporose/tratamento farmacológico , Osteoporose Pós-Menopausa/tratamento farmacológico
3.
Artigo em Inglês | MEDLINE | ID: mdl-31815976

RESUMO

The purpose of this study was to evaluate the effect that microgrooved abutments may have on peri-implant tissues. After the flapless extractions of the mandibular premolars of eight dogs, four Laser-Lok implants were placed in each mandibular quadrant, and half of them received laser-microgrooved abutments. A xenograft (MinerOss X, BioHorizons) was used in the gaps. The dogs were euthanized 12 weeks after treatment, and the histomorphometric analysis was performed. Unlike the machined abutments, the microgrooved abutments influenced the orientation of connective tissue fibers, which appeared perpendicularly and adhered to the implant-abutment surfaces, preventing the apical migration of the junctional epithelium. Laser-microgrooved abutments showed superior results.


Assuntos
Dente Suporte , Implantes Dentários , Animais , Remodelação Óssea , Implantação Dentária Endo-Óssea , Cães , Inserção Epitelial , Mandíbula
4.
JAMA ; 322(23): 2344, 2019 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-31846011
5.
JAMA ; 322(23): 2344, 2019 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-31846013
6.
Prog Orthod ; 20(1): 47, 2019 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-31867679

RESUMO

BACKGROUND: Maxillary incisor protrusion is a prevalent dental deformity and is often treated by upper incisor intrusion and retraction. The mechanical loading triggers the resorption and apposition of the bone. Alveolar bone remodeling is expected to follow orthodontic tooth movement in a one-to-one relationship. However, in many cases, the outcomes are different. Alveolar bone might still remain thick causing lip protrusion and other aesthetic problems after treatment. Additional corrective procedures such as alveoloplasty. On the other hand, if the labial bone becomes too thin, periodontal problems like gingival recession might occur. The unpredictability of the treatment result and the risk of requiring corrective procedures pose significant challenges to both the providers and patients. The aim of this study is to determine factors that can help to predict the alveolar bone reaction before maxillary incisor intrusion and retraction. METHODS: The cohort included 34 female patients (mean age 25.8 years) who were diagnosed with skeletal class II malocclusion with upper incisor protrusion. These patients underwent extraction and orthodontic treatment with upper incisor intrusion and retraction. Lateral cephalograms at pre-treatment and post-treatment were taken. Linear and angular measurements were analyzed to evaluate the alveolar bone changes based on initial conditions. RESULTS: The study found that the relative change, calculated as change in alveolar bone thickness after treatment divided by the initial alveolar thickness, was inversely correlated with the initial thickness. There was a significant increase of labial alveolar bone thickness at 9-mm apical from cementoenamel junction (B3) (P < 0.05) but no statistically significant change in the thickness at other levels. In addition, the change in angulation between the incisor and alveolar bone was inversely correlated with several initial angulations: between the initial palatal plane and upper incisor angle, between the initial palatal plane and upper incisor labial surface angle, and between the initial palatal plane and bone labial surface angle. On the other hand, the change in labial bone thickness was neither significantly correlated with the initial thickness nor significantly correlated to the amount of retraction. CONCLUSION: The unpredictability of alveolar bone remodeling after upper incisor intrusion and retraction poses significant challenges to treatment planning and patient experience. The study showed that the initial angulation between the incisor and alveolar bone is correlated with the change in angulation after treatment, the initial thickness of the alveolar bone was correlated with the relative change of the alveolar bone thickness (defined as change in thickness after treatment divided by its initial thickness), and the amount of intrusion was correlated with the alveolar bone thickness change at 9-mm apical from the cementoenamel junction after treatment. The results of the present study also revealed that the change in labial alveolar bone thickness was neither significantly correlated with the initial thickness nor significantly correlated to the amount of retraction.


Assuntos
Estética Dentária , Incisivo , Adulto , Remodelação Óssea , Cefalometria , Feminino , Humanos , Maxila , Técnicas de Movimentação Dentária
7.
Wiad Lek ; 72(11 cz 2): 2202-2209, 2019.
Artigo em Polonês | MEDLINE | ID: mdl-31860837

RESUMO

OBJECTIVE: Introduction: Mineral homeostasis is achieved through a complex interplay of several feedback processes involving primarily the bone, intestine and kidney, regulated by different proteins acting on endocrine, paracrine or autocrine levels. The dysregulation of these processes in chronic renal failure, called kidney disease (CKD) - mineral and bone disorder (CKD-MBD), although apparent, is still poorly understood. The aim: The aim of the study was an analysis of potential relationships between selected biomarkers of CKD-MBD in maintenance hemodialysis (HD) patients. PATIENTS AND METHODS: Material and Methods: In the first part of this cross-sectional study, the 25(OH)D serum concentrations were measured in 115 HD vitamin D naïve patients from 5 dialysis units located in central Poland. Thereafter in 81 patients (49 men, 32 women, aged 67 ± 13 years) with vitamin deficiency (25(OH)D <20 ng/ml) serum concentrations of 25(OH)D, 1,25(OH)2D, intact parathyroid hormone (iPTH), intact FGF23, sclerostin (SCL), osteocalcin (OC), and C-terminal telopeptide of type I collagen (CTX1) were determined. RESULTS: Results: Serum levels of both 25(OH)D and 1,25(OH)2D were low (mean values 13.4±6.72 ng/ml and 12.9 ± 9.08 pmol/l, respectively). While serum 25(OH)D correlated only with a declared time spent outside (r= 0.411; p=0.000139), serum 1,25(OH)2D was related to diuresis (r= 0.289; p=0.009), and negatively to time on dialysis (r= -0.272; p=0.014) , serum phosphate (r= -0.393; p=0.000289), FGF23(r= -0.295; p=0.008), and SCL (r= -0.260; p=0.019). There was a marked dispersion of FGF-23 serum levels across the group (mean 823±5647, median 379 pg/ml) , and - as expected - they correlated highly with phosphate (r= 0.549, p=0.000), calcium (r= 0,328, p=0,003), OC (r=0.479; p=0.000), and negatively with z 1,25(OH)2D (r= -0.295, p=0.008). Mean serum SCL levels (89.2±46.7, median 81.9 pmol/l) were 3x higher than in general population, and correlated highly positively with dialysis vintage (r=0.402; p<0.001), age (r=0.356; p=0.001), as well as negatively with 1,25(OH)2D (r= -0.260; p=0.019) and CTX1 (r= -0.293; p=0.008). CONCLUSION: Conclusions: In our hemodialysis population, in addition to profoundly impaired 1,25(OH)2D synthesis, there is also a widespread prevalence of 25(OH)D deficiency. The patients have also markedly increased serum bone-secreted proteins, FGF23, and SCL, which regulate mineral and bone metabolism and are associated with the systemic side effects of uremia. All these hormones interact one with the other, creating a sophisticated cross-talk between the bone, intestine, and the kidney.


Assuntos
Deficiência de Vitamina D , Idoso , Idoso de 80 Anos ou mais , Biomarcadores , Remodelação Óssea , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Hormônio Paratireóideo , Polônia , Diálise Renal , Vitamina D
8.
Medicine (Baltimore) ; 98(48): e18161, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31770261

RESUMO

RATIONALE: Epithelioid hemangioma (EH) of bone is an intermediate vascular tumor that can be locally aggressive. The optimum management of multifocal EH of bone is not well delineated. We described our experience treating one patient with multifocal EH of bone in an effort to document the effect of bisphosphonates in bone EH. PATIENT CONCERNS: In this report, a 53-year old male patient presented with back pain which was initially been diagnosed of multiple bone metastatic carcinoma by 18F-FDG PET/CT scan and bone scintigraphy. DIAGNOSIS: CT-guided bone biopsy of ilium indicated that puncture tissue had irregular hyperplasia of thick and thin-walled blood vessels, immunohistochemistry revealed positive staining for CD31 and CD34, negative for CAMTA-1, PCK and EMA, which confirmed the diagnosis of multiple EH. INTERVENTIONS: The patient was treated with 4 times of intravenous Zometa (zoledronate, 4 mg each time) with average three-month interval. Bone metabolic markers including serum bone specific alkaline phosphatase (BALP) and type I collagen cross-linked C-terminal telopeptide (CTX) levels were closely monitored before and after use of bisphosphonates each time. OUTCOME: BALP and CTX were significantly lowered following intravenous Zometa and the back pain improved with integrated therapy including bone graft fusion internal fixation surgery and vertebroplasty. CONCLUSIONS: EH of multiple bones responded favorably to intravenous Zometa with improvement of bone metabolic markers. After 1 year on follow-up, the patient was doing well with no significant pain. We suggest that bisphosphonates should be considered in the treatment of multifocal osteolytic EH of bone.


Assuntos
Neoplasias Ósseas , Osso e Ossos , Hemangioendotelioma Epitelioide , Imuno-Histoquímica/métodos , Metástase Neoplásica/diagnóstico , Procedimentos Ortopédicos/métodos , Ácido Zoledrônico/administração & dosagem , Biópsia/métodos , Conservadores da Densidade Óssea/administração & dosagem , Neoplasias Ósseas/diagnóstico , Neoplasias Ósseas/metabolismo , Neoplasias Ósseas/patologia , Neoplasias Ósseas/terapia , Remodelação Óssea/efeitos dos fármacos , Osso e Ossos/diagnóstico por imagem , Osso e Ossos/metabolismo , Osso e Ossos/patologia , Terapia Combinada , Diagnóstico Diferencial , Difosfonatos/administração & dosagem , Monitoramento de Medicamentos/métodos , Hemangioendotelioma Epitelioide/diagnóstico , Hemangioendotelioma Epitelioide/metabolismo , Hemangioendotelioma Epitelioide/patologia , Hemangioendotelioma Epitelioide/terapia , Humanos , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento
9.
Rev Soc Bras Med Trop ; 52: e20180441, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31596347

RESUMO

Hepatitis B is a major public health problem worldwide and associated with significant mortality. To prevent or delay the deleterious effects of chronic infection by the hepatitis B virus, patients should be carefully followed, and antiviral therapy indicated according to specific recommendations. Currently, available drugs inhibit viral replication and slow or stop the progression of inflammation and fibrosis of the liver. However, the drugs for oral use in the treatment of hepatitis B, jointly referred to as nucleoside/nucleotide analogs, are indicated for prolonged use and have potential side effects. The reduction in bone mineral density was associated with the use of tenofovir, already evaluated in patients infected with HIV because the drug is also part of the therapeutic arsenal for this viral infection. There are few studies on the effects of tenofovir in patients with mono hepatitis B. Therefore, this literature review proposes to examine how hepatitis B acts in the body and the mechanisms by which antiretroviral drugs (especially tenofovir) can affect bone metabolism.


Assuntos
Antirretrovirais/efeitos adversos , Densidade Óssea/efeitos dos fármacos , Remodelação Óssea/efeitos dos fármacos , Hepatite B Crônica/tratamento farmacológico , Antirretrovirais/administração & dosagem , Humanos , Replicação Viral/efeitos dos fármacos
10.
J Appl Oral Sci ; 27: e20180596, 2019 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-31508793

RESUMO

Bone development and healing processes involve a complex cascade of biological events requiring well-orchestrated synergism with bone cells, growth factors, and other trophic signaling molecules and cellular structures. Beyond health processes, MMPs play several key roles in the installation of heart and blood vessel related diseases and cancer, ranging from accelerating metastatic cells to ectopic vascular mineralization by smooth muscle cells in complementary manner. The tissue inhibitors of MMPs (TIMPs) have an important role in controlling proteolysis. Paired with the post-transcriptional efficiency of specific miRNAs, they modulate MMP performance. If druggable, these molecules are suggested to be a platform for development of "smart" medications and further clinical trials. Thus, considering the pleiotropic effect of MMPs on mammals, the purpose of this review is to update the role of those multifaceted proteases in mineralized tissues in health, such as bone, and pathophysiological disorders, such as ectopic vascular calcification and cancer.


Assuntos
Remodelação Óssea/fisiologia , Matriz Extracelular/fisiologia , Metaloproteinases da Matriz/fisiologia , Doenças Ósseas/metabolismo , Doenças Ósseas/fisiopatologia , Progressão da Doença , Humanos , Inibidores de Metaloproteinases de Matriz/uso terapêutico , Neoplasias/metabolismo , Neoplasias/fisiopatologia , Osteoblastos/fisiologia , Inibidores Teciduais de Metaloproteinases/fisiologia , Calcificação Vascular/metabolismo , Calcificação Vascular/fisiopatologia
11.
Eur J Endocrinol ; 181(5): 525-537, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31536965

RESUMO

Objective: To evaluate the effect of insulin resistance in obesity on the expression in whole blood of mRNA and miRNA affecting bone homeostasis as well as to estimate the influence of oral glucose load (OGTT) on serum osteocalcin concentration in obese individuals with and without insulin resistance. Design: Cross-sectional study. Methods: Carboxylated (cOC), undercarboxylated (ucOC) and total osteocalcin were measured by ELISA in the serum of obese subjects with insulin resistance (n = 41) and obese subjects without insulin resistance (n = 41) (control group) during OGTT. Analysis of gene expression (microarray) and miRNAs (real-time PCR) was performed in venous blood (representating samples) collected before OGTT from obese with insulin resistance and controls. Results: Obese subjects with insulin resistance (higher HOMA-IR and lower oral glucose insulin sensitivity index) presented significantly increased expression of WNT signalling inhibitors (DKK1, DKK2, SOST, SFRP1) and downregulation of the key factor in WNT signalling - ß catenin participating in osteoblasts differentiation. Expression of miRNA involved in osteoblastogenesis was also inhibited (miR-29b, miR-181a, miR-210, miR-324-3p). During OGTT, contrary to the control group, subjects with insulin resistance presented suppression of cOC and total OC decrease after 1 and 2 h of oral glucose load. Conclusions: Obese subjects with insulin resistance may have defects in osteoblastogenesis that was demonstrated via key signalling molecules mRNA downregulation, and increased expression of WNT antagonists as well as inhibition of expression of miRNA participating in the regulation of osteoblast differentiation. Disturbed osteoblastogenesis in insulin-resistant subjects results in the suppression of blood carboxylated and total osteocalcin decrease during OGTT.


Assuntos
Remodelação Óssea/fisiologia , Resistência à Insulina/fisiologia , MicroRNAs/sangue , RNA Mensageiro/sangue , Adulto , Estudos Transversais , Ensaio de Imunoadsorção Enzimática , Feminino , Teste de Tolerância a Glucose , Humanos , Masculino , Análise em Microsséries , Pessoa de Meia-Idade , Obesidade/etiologia , Obesidade/metabolismo , Osteoblastos/metabolismo , Osteoclastos/metabolismo , Via de Sinalização Wnt/fisiologia
12.
Orthopade ; 48(11): 911-916, 2019 Nov.
Artigo em Alemão | MEDLINE | ID: mdl-31531702

RESUMO

Inflammatory rheumatic diseases are often associated with secondary osteoporosis, as many inflammatory messengers can interfere with bone metabolism and adversely affect it. In addition to a decrease in densitometric bone density, remodeling occurs in the trabecular bone, which can lead to a disturbed microarchitecture and increase the risk of fracture.Central to this is the close integration of bone metabolism and the immune system. Proinflammatory cytokines play an important role not only in the inflammatory process, but also as mediators of bone resorption because they stimulate osteoclastogenesis and induce further signal transduction cascades with negative influence on the bone. The understanding gained in recent years of the underlying immunological processes has led to the development of new and targeted treatment approaches.


Assuntos
Reabsorção Óssea/imunologia , Citocinas/fisiologia , Osteoporose , Doenças Reumáticas/imunologia , Remodelação Óssea , Reabsorção Óssea/metabolismo , Humanos , Mediadores da Inflamação/fisiologia , Osteoblastos/fisiologia , Osteoclastos/fisiologia , Doenças Reumáticas/metabolismo
13.
Int J Oral Maxillofac Implants ; 34(6): 1328­1336, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31532826

RESUMO

PURPOSE: There is a lack of knowledge concerning the critical buccal bone thickness required for securing favorable functional and esthetic outcomes, conditioned to the dimensional changes after implant placement. A preclinical study was therefore carried out to identify the critical buccal bone wall thickness for minimizing bone resorption during physiologic and pathologic bone remodeling. MATERIALS AND METHODS: A randomized, two-arm in vivo study in healthy beagle dogs was carried out. The first group of dogs was sacrificed 8 weeks after implant placement for histomorphometric examination of postsurgical resorption of the buccal bone wall. The second group of dogs was monitored during three ligature-induced peri-implantitis episodes and a spontaneous progression episode. Morphometric and clinical variables were defined for the study of physiologic and pathologic buccal and lingual bone loss. RESULTS: Seventy-two implants were placed in healed mandibular ridges of 12 beagle dogs. Two groups were defined: 36 implants were placed in sites with a thin buccal bone wall (< 1.5 mm), and 36 were placed in sites with a thick buccal bone wall (≥ 1.5 mm). No implants failed during the study period. For the great majority of the histomorphometric parameters, a critical buccal bone wall thickness of at least 1.5 mm seemed to be essential for maintaining the buccal bone wall during physiologic and pathologic bone resorption. Suppuration (+) and mucosal recession (-) were more often associated with implants placed in sites with a thin buccal bone wall. CONCLUSION: A critical buccal bone wall thickness of 1.5 mm at implant placement is advised, since a thicker peri-implant buccal bone wall (> 1.5 mm) is exposed to significantly less physiologic and pathologic bone loss compared with a thinner buccal bone wall (< 1.5 mm).


Assuntos
Remodelação Óssea , Implantes Dentários , Estética Dentária , Animais , Implantação Dentária Endo-Óssea , Cães , Mandíbula , Distribuição Aleatória , Zigoma
14.
Mater Sci Eng C Mater Biol Appl ; 104: 109934, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31500061

RESUMO

Recently, a novel 3D titanium-mesh scaffold with bone grafting material has been proposed to reconstruct the large defect of mandible. However, how to design and optimize the 3D scaffolds of mandible is still unclear. Therefore, the aim of this study was to investigate the optimization of 3D scaffolds for mandibular defect. Both the biomechanical behavior and mechanobiological property of scaffolds were considered in this study. Four configurations (regular hexahedron, cuboctahedron, regular dodecahedron, and diamond) and three strut diameters (0.2 mm, 0.5 mm and 0.8 mm) were divided into 12 groups. By employing Finite Element Analysis and bone "Mechnostat" theory, the optimal unit cell was selected from 12 scaffolds. Then, the original implant for mandible defects was designed with the optimal unit cell, and the final implant was optimized to promote osteogenesis and avoid mechanical failure under bi-lateral chewing bite (200N) and maximum force (worse-case) bite (800 N). The results illustrated a strong correlation between the configurations and the load transmission capacity, while mechanical failure highly depended on strut size and architecture. Regular dodecahedron with a strut diameter of 0.8 mm provided a good load transfer to bone tissue while resisting the mechanical failure. Ultimately, the optimized implant was constructed with regular dodecahedron unit cell, and the strut diameters of scaffold gradually varied according to the biomechanical analysis. The computational results indicated that the optimized implant can provide an excellent mechanical environment for bone regeneration, thus achieving a long-term stability and occlusal reconstruction with dental implant. This study is expected to provide a scientific basis for the design and optimization of 3D mesh scaffolds to reconstruct a mandibular functionally and aesthetically.


Assuntos
Simulação por Computador , Implantes Dentários , Mandíbula/cirurgia , Telas Cirúrgicas , Titânio/farmacologia , Remodelação Óssea/efeitos dos fármacos , Análise de Elementos Finitos , Humanos , Músculos/efeitos dos fármacos , Porosidade , Estresse Mecânico , Tecidos Suporte/química
15.
Clin Oral Implants Res ; 30(12): 1179-1189, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31494964

RESUMO

OBJECTIVES: Whereas stationary stability of implants has been postulated for decades, recent studies suggested a phenomenon termed implant migration. This describes a change in position of implants as a reaction to applied forces. The present study aims at employing image registration of in vivo micro-CT scans from different time points and to assess (a) if migration of continuously loaded implants is possible and (b) migration correlates with the force magnitude. MATERIAL AND METHODS: Two customized machined implants were placed in the dorsal portion of caudal vertebrae in n = 61 rats and exposed to standardized forces (0.5 N, 1.0 N, and 1.5 N) applied through a flat nickel-titanium contraction spring, or no forces (control). Micro-CT scans were performed at 0, 1, 2, 4, 6, and 8 weeks after surgery. The baseline image was registered with the forthcoming scans. Implant migration was measured as the Euclidean distance between implant tips. Bone remodeling was assessed between the baseline and the forthcoming scans. RESULTS: The findings confirmed a positional change of the implants at 2 and 8 weeks of healing, and a linear association between applied force and velocity of movement (anterior implant: χ2  = 12.12, df = 3, and p = .007 and posterior implant: χ2  = 20.35, df = 3, and p < .001). Bone apposition was observed around the implants and accompanied by formation of load-bearing trabeculae and a general cortical thickening close and also distant to the implants. CONCLUSION: The present analysis confirmed that implants can migrate in bone. The applied forces seemed to stimulate bone thickening, which could explain why implants migrate without affecting stability.


Assuntos
Implantes Dentários , Animais , Remodelação Óssea , Osso e Ossos , Osseointegração , Ratos , Coluna Vertebral , Titânio , Microtomografia por Raio-X
16.
Comput Methods Biomech Biomed Engin ; 22(16): 1247-1257, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31497997

RESUMO

One of the major causes of implant loosening is due to excessive bone resorption surrounding the implant due to bone remodelling. The objective of the study is to investigate the effects of implant material and implant-bone interface conditions on bone remodelling around tibia bone due to total ankle replacement. Finite element models of intact and implanted ankles were developed using CT scan data sets. Bone remodelling algorithm was used in combination with FE analysis to predict the bone density changes around the ankle joint. Dorsiflexion, neutral, and plantar flexion positions were considered, along with muscle force and ligaments. Implant-bone interfacial conditions were assumed as debonded and bonded to represent non-osseointegration and fully osseointegration at the porous coated surface of the implant. To investigate the effect of implant material, three finite element models having different material combinations of the implant were developed. For model 1, tibial and talar components were made of Co-Cr-Mo, and meniscal bearing was made of UHMWPE. For model 2, tibial and talar components were made of ceramic and meniscal bearing was made of UHMWPE. For model 3, tibial and talar components were made of ceramic and meniscal bearing was made of CFR-PEEK. Changes in implant material showed no significant changes in bone density due to bone remodelling. Therefore, ceramic appears to be a viable alternative to metal and CFR-PEEK can be used in place of UHMWPE. This study also indicates that proper bonding between implant and bone is essential for long-term survival of the prosthetic components.


Assuntos
Artroplastia de Substituição do Tornozelo , Remodelação Óssea/fisiologia , Próteses e Implantes , Tíbia/fisiologia , Algoritmos , Densidade Óssea/fisiologia , Interface Osso-Implante/fisiologia , Cartilagem/fisiologia , Simulação por Computador , Análise de Elementos Finitos , Humanos , Osseointegração/fisiologia
17.
Pan Afr Med J ; 33: 37, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31384352

RESUMO

Introduction: Osteoporosis is characterized by low bone mass and density, as well as change in microarchitecture of bone tissue leading to decreased bone strength. In vitro research shows nicotine can increase osteoblast activity and proliferation, also suppress osteoclast activity. Therefore we explore nicotine anti-resorptive property by in vivo true experimental and randomized posttest only controlled group research that was conducted in 18-20 weeks old Rattus norvegicus. Methods: Twenty-five female rats were divided into five groups, with 5 rats per group. The first group represented normal rats (Sham), while the second to fifth group underwent bilateral ovariectomy. The second group serves as positive control group (ovariectomy-only/OVX). The third to fifth group serve as dose 1 (P1-0.25mg/kg), dose 2 (P2-0.5 mg/kg), and Dose 3 (P3-0.75 mg/kg) treatment group receiving daily per-oral nicotine for 28 days, started 3 weeks post- ovariectomy. After 28 days treatment, the serum was checked. Results: Nicotine has dose-dependent manner on serum osteocalcin and serum DPD level. Level of osteocalcin in P2 group was significantly lower (Mann-Whitney, p = 0.008) compared to OVX group (59.4% lower). Level of DPD in all group was not significantly different (ANOVA, p < 0.05) but shows lowest level in P2 group. For serum calcitonin level, there's no significant different between groups. Conclusion: Nicotine at right low-dose might be able to inhibit osteoclast activity, thus open a possibility of anti-resorptive property of nicotine.


Assuntos
Densidade Óssea/efeitos dos fármacos , Nicotina/farmacologia , Osteoclastos/efeitos dos fármacos , Osteoporose/prevenção & controle , Aminoácidos/sangue , Animais , Biomarcadores/metabolismo , Remodelação Óssea/efeitos dos fármacos , Osso e Ossos/efeitos dos fármacos , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Feminino , Nicotina/administração & dosagem , Osteoblastos/efeitos dos fármacos , Osteoblastos/metabolismo , Osteocalcina/sangue , Osteoclastos/metabolismo , Osteoporose/patologia , Ovariectomia , Ratos , Ratos Wistar
18.
Artigo em Inglês | MEDLINE | ID: mdl-31449582

RESUMO

Peri-implant bone remodeling occurs in all osseointegrated implants and can be defined as an adaptive process of bone around the implant in response to functional loading. This retrospective study evaluated the marginal bone remodeling around dental implants with external hexagonal connections in function for more than 10 years. The sample consisted of 17 implants placed in the posterior region of the mandible to replace one or several teeth. For all cases, the initial periapical radiograph was assessed together with a subsequent follow-up periapical radiograph. Image analysis was performed using ImageJ software to establish the initial bone measurements and subsequent bone loss. The data were statistically analyzed using paired t test at a significance level of 5%. There was significant bone remodeling when the baseline and follow-up were compared (P < .001). The mean values of peri-implant bone remodeling on the mesial aspect were 0.90 ± 0.63 mm vertically and 1.17 ± 0.60 mm horizontally. The distal aspect of the implants showed 1.01 ± 0.82 mm and 1.06 ± 0.75 mm of marginal bone remodeling vertically and horizontally, respectively. Within the limitations of this study, marginal bone remodeling was visible, and bone levels around the external hexagon implants remain stable after 10 years of function.


Assuntos
Perda do Osso Alveolar , Implantes Dentários , Remodelação Óssea , Implantação Dentária Endo-Óssea , Planejamento de Prótese Dentária , Prótese Dentária Fixada por Implante , Seguimentos , Mandíbula , Estudos Retrospectivos
19.
J Oral Implantol ; 45(5): 403-407, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31429640

RESUMO

Managing medication-related osteonecrosis of the jaw (MRONJ) around a dental implant can be difficult. Although conservative treatment of MRONJ is recommended as the first-line form of management, many patients exhibit no improvement. The human recombinant parathyroid hormone teriparatide has recently been introduced for the management of MRONJ. Teriparatide is effective in the treatment of postmenopausal osteoporosis and is the only US Food and Drug Administration-approved anabolic agent that directly affects osteoblast function and contributes to bone remodeling. Herein we describe a case of MRONJ in an 85-year-old woman who was successfully treated with teriparatide. Teriparatide was administered once per week without any surgical interventions such as a sequestrectomy. Compared with most recently reported cases involving daily treatment with teriparatide, once-weekly administration of teriparatide may minimize side effects and patient discomfort. Once-weekly teriparatide application without sequestrectomy may be effective in the management of MRONJ around a dental implant.


Assuntos
Osteonecrose da Arcada Osseodentária Associada a Difosfonatos , Conservadores da Densidade Óssea , Implantes Dentários , Idoso de 80 Anos ou mais , Remodelação Óssea , Feminino , Humanos , Teriparatida
20.
Int J Oral Sci ; 11(3): 27, 2019 08 26.
Artigo em Inglês | MEDLINE | ID: mdl-31451690

RESUMO

Bone remodelling keeps going through the lifespan of human by bone formation and bone resorption. In the craniofacial region, mandibles act as the main force for biting and chewing, and also become susceptible to a common bone-loss disease, namely, apical periodontitis, once infected dental pulp is not treated timely, during which bone resorption occurs from the apical foramen to the apical bone area. Although conventional root canal treatment (RCT) can remove the most of the infection, chronical apical periodontitis due to incomplete removal of dental pulp and subsequent microleakage will become refractory and more challenging, and this process has scarcely been specifically studied as a bone remodelling issue in rat models. Therefore, to study chronical and refractory apical periodontitis owing to incomplete cleaning of infected dental pulp and microleackage in vivo, we establish a modified rat model of gradually progressive apical periodontitis by sealing residual necrotic dental pulp and introducing limited saliva, which simulates gradually progressive apical periodontitis, as observed in the clinical treatment of chronical and refractory apical periodontitis. We show that bone-loss is inevitable and progressive in this case of apical periodontitis, which confirms again that complete and sound root canal treatment is crucial to halt the progression of chronical and refractory apical periodontitis and promote bone formation. Interestingly, bone remodelling was enhanced at the initial stage of apical periodontitis in this model while reduced with a high osteoblast number afterwards, as shown by the time course study of the modified model. Suggesting that the pathological apical microenvironment reserve its hard tissue formation ability to some degree but in a disturbed manner. Hopefully, our findings can provide insights for future bone regenerative treatment for apical periodontitis-associated bone loss.


Assuntos
Remodelação Óssea , Cavidade Pulpar/fisiopatologia , Periodontite Periapical , Regeneração , Tratamento do Canal Radicular , Animais , Necrose da Polpa Dentária , Feminino , Humanos , Masculino , Periodontite Periapical/patologia , Ratos
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