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1.
Cell Prolif ; 53(10): e12886, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32794619

RESUMO

OBJECTIVES: Diabetes aggravates the risk and severity of periodontitis, but the specific mechanism remains confused. Complement 3 (C3) is closely related to complications of type 2 diabetes (T2DM). In the present study, we concentrated on whether C3 mediates the development of periodontitis in T2DM. MATERIALS AND METHODS: Levels of C3 in blood and gingival crevicular fluid (GCF) of patients were measured first. A C3-knockout diabetic mouse model was established, real-time PCR, Western blotting and histological investigation were performed to evaluate the progress of periodontitis. Microcomputed tomography (micro-CT) and TRAP staining were performed to detect alveolar bone resorption. Immunofluorescence was performed to detect polarization of macrophages. RESULTS: Our data showed that C3 levels were elevated in the blood and GCF of T2DM patients compared with non-diabetic individuals. Increased C3 was closely related to the upregulation of inflammatory cytokines including interleukin (IL)-1, IL-6 and tumour necrosis factor-alpha (TNF-α), as well as the decline of the bone volume density (BMD) and bone volume over total volume (BV/TV) of the alveolar bones in diabetic mice. The deletion of C3 inhibited inflammatory cytokines and rescued the decreased BMD and BV/TV of the alveolar bones. C3-mediated polarization of macrophages was responsible for the damage. CONCLUSION: T2DM-related upregulation of C3 contributes to the development of periodontitis by promoting macrophages M1 polarization and inhibiting M2 polarization, triggering a pro-inflammatory effect on periodontal tissues.


Assuntos
Complemento C3/metabolismo , Diabetes Mellitus Tipo 2/patologia , Macrófagos/imunologia , Periodontite/diagnóstico , Adulto , Processo Alveolar/diagnóstico por imagem , Processo Alveolar/patologia , Processo Alveolar/fisiologia , Animais , Densidade Óssea , Complemento C3/análise , Complemento C3/genética , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/patologia , Diabetes Mellitus Tipo 2/complicações , Feminino , Líquido do Sulco Gengival/metabolismo , Humanos , Interleucina-6/genética , Interleucina-6/metabolismo , Ativação de Macrófagos , Macrófagos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Pessoa de Meia-Idade , Periodontite/etiologia , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/metabolismo
2.
Comput Methods Biomech Biomed Engin ; 22(16): 1294-1302, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31553278

RESUMO

Orthodontic tooth movement is mainly regulated by the biomechanical responses of loaded periodontal ligament (PDL). We investigated the effective intervals of orthodontic force in pure maxillary canine intrusion and extrusion referring to PDL hydrostatic stress and logarithmic strain. Finite element analysis (FEA) models, including a maxillary canine, PDL and alveolar bone, were constructed based on computed tomography (CT) images of a patient. The material properties of alveolar bone were non-uniformly defined using HU values of CT images; PDL was assumed to be a hyperelastic-viscoelastic material. The compressive stress and tensile stress ranging from 0.47 to 12.8 kPa and 18.8 to 51.2 kPa, respectively, were identified as effective for tooth movement; a strain 0.24% was identified as the lower limit of effective strain. The stress/strain distributions within PDL were acquired in canine intrusion and extrusion using FEA; root apex was the main force-bearing area in intrusion-extrusion movements and was more prone to resorption. Owing to the distinction of PDL biomechanical responses to compression and tension, the effective interval of orthodontic force was substantially lower in canine intrusion (80-90 g) than in canine extrusion (230-260 g). A larger magnitude of force remained applicable in canine extrusion. This study revised and complemented orthodontic biomechanical behaviours of tooth movement with intrusive-extrusive force and could further help optimize orthodontic treatment.


Assuntos
Dente Canino/fisiologia , Análise de Elementos Finitos , Maxila/fisiologia , Processo Alveolar/fisiologia , Fenômenos Biomecânicos , Simulação por Computador , Humanos , Pressão Hidrostática , Modelos Biológicos , Ligamento Periodontal/fisiologia , Estresse Mecânico , Técnicas de Movimentação Dentária
3.
Microsc Res Tech ; 82(12): 1993-1999, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31441994

RESUMO

The success of dental implants is related to the amount, quality, and composition of the alveolar bone. The placement of platelet-rich fibrin (PRF) clot associated with a resorbable collagen membrane (RCM) in a postextraction alveolus is a technique used for ridge preservation. This case report study analyzed the ultrastructural characteristics of cross-sectioned alveolar bone that received PRF and RCM using scanning electron microscopy and the inorganic composition using "energy dispersive X-ray spectrometry," in order to explore the feasibility of this method to clinical studies. Three alveolar bone samples from two male patients (37 and 58 years old), obtained in the procedure of placing the dental implant, were analyzed. Two bone samples previously received PRF and RCM (M37 and M58), the third sample represented a physiological bone formation without treatment (M37-control). The bone sample M37 showed irregularly shaped islets of calcified material intermingled with connective tissue. The other samples, from the 58-year-old patient with PRF and RCM (M58); and the other untreated bone sample from the same 37-year-old patient (M37-control) showed similar ultrastructural morphology with trabecular conformation without islets agglomerations. The inorganic composition analysis showed higher concentrations of calcium and phosphorus in both samples treated with PRF and RCM in comparison to the untreated bone sample. The Ca/P ratio was higher in the M37 sample compared to the others samples. The results showed morphology and inorganic composition differences among the treatments used, suggesting that this method is feasible to analyze parameters of the alveolar bone tissue.


Assuntos
Processo Alveolar/fisiologia , Colágeno/uso terapêutico , Implantes Dentários , Fibrina Rica em Plaquetas/metabolismo , Adulto , Processo Alveolar/ultraestrutura , Humanos , Masculino , Microscopia Eletrônica de Varredura , Pessoa de Meia-Idade , Cirurgia Bucal/métodos
5.
Bone ; 127: 244-249, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31176735

RESUMO

Within the dental alveolar socket, the sequence of events following tooth extraction involves deposition of a provisional connective tissue matrix that is later replaced by woven bone and eventually by lamellar bone. Bone regeneration within the dental alveolar socket is unique since the space occupied by the root(s) of a tooth does not originally contain any bone. However, extracellular matrix composition of the healing alveolar socket has not previously been investigated. Here, alveolar bone biopsies representing early (7-46 months, < 4y) and late (48-60 months; 4-5y) healing periods were investigated using Raman spectroscopy, X-ray micro-computed tomography and backscattered electron scanning electron microscopy. Partially or completely edentulous individuals and those with a smoking habit were not excluded. Between < 4y and 4-5y, mineral crystallinity and bone mineral density increase, phenylalanine, proline/hydroxyproline, and bone surface-to-volume ratio decrease, while the carbonate-to-phosphate ratio, the mineral-to-matrix ratio, and the collagen crosslink ratio remain relatively unchanged. Observed exclusively at 4-5y, hypermineralised osteocyte lacunae contain spherical and rhomboidal mineral nodules. Spearman correlation analysis reveals several significant, high (ρ = 0.7-0.9; p ≤ 0.01) and moderate (ρ = 0.5-0.7; p ≤ 0.01) correlations. Mineral crystallinity and proline/hydroxyproline, the carbonate-to-phosphate ratio and phenylalanine, mineral crystallinity and bone surface-to-volume ratio, the carbonate-to-phosphate ratio and bone surface-to-volume ratio, proline/hydroxyproline and bone mineral density, and bone mineral density and bone surface-to-volume ratio are negatively correlated. Mineral crystallinity and bone mineral density, and proline/hydroxyproline and bone surface-to-volume ratio are positively correlated. Although bone regeneration in the dental alveolar socket follows typical bone healing patterns, the compositional and microstructural patterns reveal mature bone at <4y with indications of better mechanical competence at 4-5y.


Assuntos
Processo Alveolar/fisiologia , Regeneração Óssea/fisiologia , Matriz Extracelular/metabolismo , Alvéolo Dental/fisiologia , Biópsia , Densidade Óssea , Pré-Escolar , Cristalização , Humanos , Minerais/metabolismo , Osteócitos/metabolismo , Análise Espectral Raman , Estatísticas não Paramétricas , Cicatrização
6.
Int Orthod ; 17(2): 216-226, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31000446

RESUMO

INTRODUCTION: The aim of this study was to compare different corticotomy approaches and determine their biomechanical effects on rate of canine displacement when compared to conventional orthodontics. METHOD: Three-dimensional Finite Element Models with conventional non-corticotomy approach (model 1) and three corticotomy approaches ensuing buccal and palatal vertical cuts (model 2), interseptal bone reduction (model 3), buccal vertical cuts (model 4) were fabricated. Displacement of the canine and von Mises stresses in the canine and trabecular bone were calculated and compared under a distal retraction force of 1.5N. RESULTS: The maximum displacement of canine with minimum anchorage loss was seen in model 3 followed by model 2, model 4 and model 1. The maximum equivalent (von Mises) stress was concentrated mainly on the distal side of canine in model 3 and had a uniform distribution of stresses on entire root surface. CONCLUSIONS: Corticotomy approaches effectively accelerated maxillary canine retraction, exhibiting twice the rate of canine movement with minimum anchorage loss when compared to non-corticotomy approach. Corticotomy with interseptal bone reduction was most effective in terms of canine displacement and stress distribution.


Assuntos
Dente Canino/fisiologia , Análise do Estresse Dentário , Análise de Elementos Finitos , Imageamento Tridimensional/métodos , Técnicas de Movimentação Dentária/métodos , Processo Alveolar/fisiologia , Fenômenos Biomecânicos , Osso Esponjoso , Simulação por Computador , Modelos Dentários , Humanos , Maxila , Procedimentos de Ancoragem Ortodôntica , Desenho de Aparelho Ortodôntico , Braquetes Ortodônticos , Fechamento de Espaço Ortodôntico/métodos , Fios Ortodônticos , Osteotomia/métodos , Ligamento Periodontal , Estresse Mecânico , Técnicas de Movimentação Dentária/instrumentação , Raiz Dentária/fisiologia
7.
J Endod ; 45(4): 435-441, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30851933

RESUMO

INTRODUCTION: Although the therapeutic potential of human dental pulp stem cells (hDPSCs) has been studied for bone regeneration, the therapeutic efficiency needs further consideration and examinations for clinical applications. Thus, the aims of this study were to evaluate the effect of 2,3,5,4'-tetrahydroxystilbene-2-O-ß-D-glucoside (THSG) on the osteogenic differentiation of hDPSCs and to examine the therapeutic efficiency of the THSG-enhanced osseous potential of hDPSCs in alveolar bony defects of rats. METHODS: Expressions of osteogenic messenger RNAs (including ALP, RUNX2, BGLAP, and AMBN) were examined by quantitative real-time polymerase chain reaction. Alizarin red S staining was conducted to analyze THSG-induced mineralization of hDPSCs. To investigate the regenerative effects of THSG-treated hDPSCs on dental alveolar bone, bony defects were created in male Sprague-Dawley rats. Defects were treated with Matrigel (Corning Inc, Corning, NY), hDPSCs, or hDPSCs + THSG. After 2 weeks, defect healing was evaluated by micro-computed tomographic and histologic analyses. RESULTS: In the cell model, THSG induced osteogenesis-associated genes (ALP, RUNX2, and BGLAP) and an enamel-related gene (AMBN), resulting in mineralization as detected by alizarin red S staining after 2 weeks of treatment. In the animal model, THSG increased all parameters of bone formation (the relative bone volume, trabecular thickness, trabecular number, and trabecular separation) in alveolar bony defects of rats. THSG not only improved the quality of newly formed bone but also the quantity of new bone. CONCLUSIONS: These results showed important findings in revealing the THSG-enhanced osteogenic differentiation of hDPSCs and THSG-facilitated bone regeneration, which may provide an alternative option for cell-based regenerative therapy.


Assuntos
Perda do Osso Alveolar/terapia , Processo Alveolar/fisiologia , Regeneração Óssea/efeitos dos fármacos , Regeneração Óssea/fisiologia , Diferenciação Celular , Polpa Dentária/citologia , Glucosídeos/farmacologia , Osteogênese , Transplante de Células-Tronco , Células-Tronco/fisiologia , Estilbenos/farmacologia , Adolescente , Adulto , Animais , Modelos Animais de Doenças , Feminino , Humanos , Masculino , Osteogênese/efeitos dos fármacos , Osteogênese/genética , Ratos Sprague-Dawley , Medicina Regenerativa/métodos , Estimulação Química , Adulto Jovem
8.
Am J Orthod Dentofacial Orthop ; 155(3): 388-397, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30826042

RESUMO

INTRODUCTION: The aim of this finite element study was to analyze and clarify the mechanics of tooth movement patterns for total distalization of the mandibular dentition based on force angulation. METHODS: Long-term orthodontic movement of the mandibular dentition was simulated by accumulating the initial displacement of teeth produced by elastic deformation of the periodontal ligament. RESULTS: Displacement of each tooth was caused by movement of the whole dentition, elastic deflection of the archwire, and clearance gap between the archwire and bracket slot. The whole dentition was rotated clockwise or counterclockwise when the line of action of the force passed below or above the center of resistance. Elastic deflection of the archwire induced a lingual tipping of the anterior teeth. It became larger when increasing the magnitude of angulation. The archwire could be rotated within the clearance gap between the archwire and the bracket slot, and thereby the teeth tipped. CONCLUSIONS: Mechanics of total mandibular distalization was clarified. Selective use of force angulation with a careful biomechanical understanding can achieve proper distalization of the whole mandibular dentition.


Assuntos
Análise de Elementos Finitos , Má Oclusão de Angle Classe III/terapia , Mandíbula/fisiologia , Técnicas de Movimentação Dentária , Processo Alveolar/fisiologia , Fenômenos Biomecânicos , Módulo de Elasticidade , Humanos , Braquetes Ortodônticos , Fios Ortodônticos , Ligamento Periodontal/fisiologia
9.
Plast Reconstr Surg ; 143(5): 1385-1395, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30789479

RESUMO

BACKGROUND: Bone morphogenetic proteins (BMPs) have played a central role in the regenerative therapies for bone reconstruction, including alveolar cleft and craniofacial surgery. However, the high cost and significant adverse effect of BMPs limit their broad application. Hydroxycholesterols, naturally occurring products of cholesterol oxidation, are a promising alternative to BMPs. The authors studied the osteogenic capability of hydroxycholesterols on human mesenchymal stem cells and the impact of hydroxycholesterols on a rodent alveolar cleft model. METHODS: Human mesenchymal stem cells were treated with control medium or osteogenic medium with or without hydroxycholesterols. Evaluation of cellular osteogenic activity was performed. A critical-size alveolar cleft was created and one of the following treatment options was assigned randomly to each defect: collagen sponge incorporated with hydroxycholesterols, BMP-2, or no treatment. Bone regeneration was assessed by means of radiologic and histologic analyses and local inflammation in the cleft evaluated. Moreover, the role of the hedgehog signaling pathway in hydroxycholesterol-mediated osteogenesis was examined. RESULTS: All cellular osteogenic activities were significantly increased on human mesenchymal stem cells treated with hydroxycholesterols relative to others. The alveolar cleft treated with collagen sponge with hydroxycholesterols and BMP-2 demonstrated robust bone regeneration. The hydroxycholesterol group revealed histologically complete bridging of the alveolar defect with architecturally mature new bone. The inflammatory responses were less in the hydroxycholesterol group compared with the BMP-2 group. Induction of hydroxycholesterol-mediated in vitro osteogenesis and in vivo bone regeneration were attenuated by hedgehog signaling inhibitor, implicating involvement of the hedgehog signaling pathway. CONCLUSION: Hydroxycholesterols may represent a viable alternative to BMP-2 in bone tissue engineering for alveolar cleft.


Assuntos
Alveoloplastia/métodos , Proteína Morfogenética Óssea 2/farmacologia , Regeneração Óssea/efeitos dos fármacos , Hidroxicolesteróis/farmacologia , Osteogênese/efeitos dos fármacos , Fator de Crescimento Transformador beta/farmacologia , Processo Alveolar/efeitos dos fármacos , Processo Alveolar/fisiologia , Animais , Proteína Morfogenética Óssea 2/economia , Técnicas de Cultura de Células , Linhagem Celular , Meios de Cultura/química , Meios de Cultura/economia , Meios de Cultura/farmacologia , Humanos , Hidroxicolesteróis/economia , Masculino , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/fisiologia , Modelos Animais , Ratos , Ratos Sprague-Dawley , Proteínas Recombinantes/economia , Proteínas Recombinantes/farmacologia , Tecidos Suporte/química , Tecidos Suporte/economia , Fator de Crescimento Transformador beta/economia
10.
Anat Sci Int ; 94(3): 238-244, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30747352

RESUMO

Several methods have been developed to regenerate lost alveolar bone. Platelet-rich fibrin (PRF) is a useful adjunct for new bone formation in dentistry. To elucidate the effect of advanced PRF (A-PRF) on bone formation, we inserted A-PRF clots in sockets after tooth extraction. Premolars were extracted from beagle dogs, and A-PRF was applied to the socket. New bone formation was assessed using histological and immunofluorescence examinations, and the bone formation ratio was evaluated 14 and 30 days postoperatively. Histological examination revealed newly formed bone filling the sockets up to the center in the A-PRF group at 14 days postoperatively, while thick and regular bone trabeculae were arranged in porous bone after 30 days. Higher expressions of osteocalcin and osteopontin were observed in newly formed bone in the A-PRF group, compared to the control group. The bone formation ratio was also higher in the A-PRF group than in the control group. Thus, A-PRF application may result in enhanced new bone formation and may aid in accelerating bone formation. A-PRF was more rapid than a self-limiting process during induction of bone formation by enhancing osteoblast activity and may be useful for bone formation in clinical medicine.


Assuntos
Processo Alveolar/fisiologia , Osteogênese/efeitos dos fármacos , Fibrina Rica em Plaquetas/fisiologia , Processo Alveolar/metabolismo , Animais , Cães , Feminino , Osteoblastos/fisiologia , Osteocalcina/metabolismo , Osteopontina/metabolismo , Estimulação Química , Fatores de Tempo
11.
Acta Odontol Scand ; 77(3): 184-188, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30623708

RESUMO

OBJECTIVE: To experimentally investigate the effects of increased masticatory muscle function on the transverse cranial dimensions on adult rats with an earlier reduced masticatory muscle function. MATERIAL AND METHOD: Sixty young male rats were used. The experimental group received soft diet for a prolonged period, so that the animals developed weak masticatory muscles. A control group received ordinary hard food during the whole experimental period (27 weeks). After 21 weeks when the animals had nearly ceased their body growth the rats in the experimental group were divided into two groups. One group continued with soft diet until the end of the experiment (hypofunctional group). The other group received ordinary hard food to get the possibility to retrain their masticatory muscles (rehabilitation group). At week 21 and at the end of the experimental period (week 27), axial cephalograms were taken. Fourteen landmarks were defined to measure seven transverse distances of the skull. RESULTS: The increase of the anterior zygomatic arch width and interzygomatic width during the experimental period were larger in the rehabilitation group compared to both the normal and the hypofunctional group. CONCLUSION: Retraining of masticatory muscles in adult rats leads to increase of some transverse cranial dimensions.


Assuntos
Processo Alveolar/fisiologia , Densidade Óssea/fisiologia , Mastigação/fisiologia , Músculos da Mastigação/fisiologia , Processo Alveolar/anatomia & histologia , Animais , Cefalometria , Masculino , Músculos da Mastigação/anatomia & histologia , Ratos , Ratos Sprague-Dawley
12.
Acta Biomater ; 85: 282-293, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30605770

RESUMO

Bone loss around tooth extraction sites can occur, thus making future placement of dental implants difficult. Alveolar bone regeneration can be guided by the application of a nanofibrous bone graft coupled with osteoinductive proteins/peptides, following tooth loss or tooth extraction. In the present study, we demonstrate the potential of mineralized nanofiber segments coupled with calcium-binding bone morphogenetic protein 2 (BMP-2) mimicking peptides for periodontal bone regeneration. Thin electrospun nanofiber membranes of PLGA-collagen-gelatin (2:1:1 wt ratios) were mineralized in 10× modified simulated body fluid (10× mSBF) and cryocut to segments of 20 µm. For predetermined weights of the mineralized nanofiber segments, it was possible to load various amounts of heptaglutamate E7-domain-conjugated BMP-2 peptide. Mineralized short fiber grafts (2 mg), with and without E7-BMP-2 peptides, were implanted into 2 mm × 2 mm (diameter × depth) critical-sized socket defects created in rat maxillae, following extraction of the first molar teeth. A sustained release profile of E7-BMP-2 from the mineralized nanofiber segments was recorded over 4 weeks. X-ray microcomputed tomography (µ-CT) analysis of peptide-loaded nanofiber graft filled defects revealed ∼3 times greater new bone volume and bone mineral density over 4 weeks in comparison to unfilled control defects. Further, histopathology data confirmed the formation of greater new osseous tissue in the BMP2 peptide-loaded, mineralized nanofiber segment group than that of fibrous connective tissue in the unfilled defect group. Altogether, the mineralized nanofiber segments coupled with E7-BMP-2 peptides may be an effective treatment option for alveolar bone loss and defects. STATEMENT OF SIGNIFICANCE: With the high incidence of dental implants/fixtures for missing teeth, the success of the surgical procedures in restorative dentistry is dictated by the quality and quantity of the supporting alveolar bone. To address the problem of alveolar bone loss and defects due to tumor, periodontitis, or even postextraction remodeling, the present study is the first report on the application of mineralized nanofiber fragments coupled with calcium-binding osteoinductive BMP-2 peptides as a synthetic graft material for oral bone regeneration. The ease of fabrication and application of cryocut mineralized nanofiber fragments as maxillofacial bone defect fillers present a promising alternative to the current dental bone graft formulations. Furthermore, the nanofiber segments may also be utilized for several biomedical applications including hemostasis, soft tissue engineering, and wound healing.


Assuntos
Processo Alveolar/fisiologia , Proteína Morfogenética Óssea 2/farmacologia , Regeneração Óssea/efeitos dos fármacos , Cálcio/metabolismo , Minerais/química , Nanofibras/química , Peptídeos/farmacologia , Processo Alveolar/diagnóstico por imagem , Processo Alveolar/efeitos dos fármacos , Animais , Bovinos , Linhagem Celular , Colágeno/química , Liberação Controlada de Fármacos , Feminino , Gelatina/química , Maxila/diagnóstico por imagem , Maxila/efeitos dos fármacos , Maxila/patologia , Camundongos , Nanofibras/ultraestrutura , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/química , Ratos Sprague-Dawley , Suínos , Microtomografia por Raio-X
13.
Oral Dis ; 25(2): 550-560, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30536847

RESUMO

OBJECTIVES: To investigate the effect of local injection of receptor activator of nuclear factor kappa B ligand (RANKL) on experimental tooth movement and subsequent alveolar bone remodelling in mice. MATERIALS AND METHODS: Sixty mice were randomised to receive daily local RANKL or phosphate-buffered saline injections in the buccal premaxillary bone for 14 of 21 days of incisor movement, followed by a 21-day retention period. Five mice from each group were euthanised on days 0, 3, 7, 14, 21 and 42, and specimens were prepared for haematoxylin and eosin, tartrate-resistant acid phosphatase and immunohistochemical staining. Five mice from each group were subjected to serial microcomputed tomography until day 42 for tooth movement and bone volume quantification. RESULTS: The experimental group showed significantly greater tooth movement and bone volume reduction on days 14 and 21; an increased osteoclast number on days 3, 7, 14 and 21; and no difference on day 42. Higher RANKL expression was observed on days 7 and 14, with remarkable alkaline phosphatase activity. No significant systemic changes were observed. CONCLUSION: Local RANKL injection leads to increased osteoclastic activity and facilitates tooth movement, followed by subsequent alveolar bone formation; this implies a reversible transitional acceleration of bone resorption.


Assuntos
Processo Alveolar/fisiologia , Remodelação Óssea/efeitos dos fármacos , Ligante RANK/farmacologia , Mobilidade Dentária/diagnóstico por imagem , Fosfatase Alcalina/metabolismo , Processo Alveolar/patologia , Animais , Contagem de Células , Injeções , Masculino , Maxila/patologia , Camundongos , Camundongos Endogâmicos ICR , Osteoblastos/metabolismo , Osteoclastos/patologia , Ligamento Periodontal/metabolismo , Ligante RANK/metabolismo , Distribuição Aleatória , Estresse Mecânico , Mobilidade Dentária/patologia , Microtomografia por Raio-X
15.
J Prosthodont ; 28(2): 185-194, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30515911

RESUMO

PURPOSE: The aim of this study was to evaluate stress distributions on implants and alveolar bone due to occlusal load produced during chewing by prostheses prepared according to the All-on-Four concept with different occlusal schemes using a finite element analysis method. MATERIALS AND METHODS: On standard jaw models, teeth were set in accordance with the basic standards of canine-guided occlusion, group function occlusion, bilateral balanced occlusion (BBO), lingualized occlusion, and monoplane occlusion schemes. Three-dimensional (3D) images of these models were obtained using a surface scanner. Implants, superstructures, the maxilla, and mandible were modeled in the All-on-Four concept with 3D modeling software. Forces were defined on contacts formed in maximum intercuspation, lateral, and protrusive movement position for all 5 occlusion types. Stress outputs were recorded as maximum and minimum principal stresses (Pmax , Pmin ) and von Mises stress values for the implants. RESULTS: The highest Pmax value for the maxilla was observed in cortical bone in the group function occlusion during lateral movement (15.56 MPa). For the mandible, the highest Pmax value was observed on the cortical bone in maximum intercuspation of lingualized occlusion (72.75 MPa). The highest Pmin value for the maxilla was observed during the lateral movement in group function and for the mandible in BBO (-29.23 and -86.31 MPa, respectively). The lowest stress values were observed with canine-guided occlusion in all related conditions and on all structures. CONCLUSIONS: With the limitations of this simulation study, considering stresses on alveolar bone and implants in All-on-Four applications, the use of canine-guided occlusion may be suggested.


Assuntos
Implantes Dentários , Oclusão Dentária , Análise do Estresse Dentário/métodos , Análise de Elementos Finitos , Processo Alveolar/fisiologia , Fenômenos Biomecânicos , Força de Mordida , Simulação por Computador , Modelos Dentários , Planejamento de Prótese Dentária , Prótese Dentária Fixada por Implante , Imageamento Tridimensional , Mastigação/fisiologia , Software
16.
J Periodontal Res ; 54(3): 300-309, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30511378

RESUMO

OBJECTIVES: The inhibitory action of the superficial gingival connective tissues may limit the regenerative potential of alveolar bone in periodontal therapy or dental implant applications. The aims of this study were to investigate the hypothesis that gingival fibroblasts (GF) can inhibit bone morphogenetic protein (BMP)-induced osteoblastic differentiation, to determine their expression of BMP inhibitors, and finally to determine whether reduction of these inhibitors can relieve suppression of osteoblastic differentiation. METHODS: Gingival fibroblasts were co-cultured either directly or indirectly with calvarial osteoblasts to assess alkaline phosphatase inhibitory activity, a marker of osteoblastic differentiation. To test total BMP-inhibitory activity of rat GF, conditioned media (GFCM) were collected from cultures. ROS 17/2.8 osteoblastic cells were stimulated with BMP2, together with GFCM. Inhibitor expression was tested using RT-qPCR, Western blotting and in situ hybridization. Removal of inhibitors was carried out using immunoprecipitation beads. RESULTS: Co-culture experiments showed GF-secreted factors that inhibit BMP-stimulated ALP activity. 10 ng/ml BMP2 increased alkaline phosphatase expression in ROS cells by 41%. GFCM blocked BMP activity which was equivalent to the activity of 100 ng/ml Noggin, a well-described BMP inhibitor. Cultured gingival fibroblasts constitutively expressed BMP antagonist genes from the same subfamily, Grem1, Grem2 and Nbl1 and the Wnt inhibitor Sfrp1. Gremlin1 (6.7 × reference gene expression) had highest levels of basal expression. ISH analysis showed Gremlin1 expression was restricted to the inner half of the gingival lamina propria and the PDL. Removal of Gremlin1 protein from GFCM eliminated the inhibitory effect of GFCM on ALP activity in ROS cells. Subsequent addition of recombinant Gremlin1 restored the inhibitory activity. CONCLUSIONS: Factors secreted by gingival fibroblasts inhibit BMP-induced bone formation and a range of BMP inhibitors are constitutively expressed in gingival connective tissues. These inhibitors, particularly Gremlin1, may limit coronal alveolar bone regenerative potential during oral and periodontal surgery.


Assuntos
Proteína Morfogenética Óssea 2/farmacologia , Diferenciação Celular , Fibroblastos/fisiologia , Gengiva/citologia , Osteoblastos/fisiologia , Osteogênese , Fosfatase Alcalina/antagonistas & inibidores , Fosfatase Alcalina/metabolismo , Processo Alveolar/fisiologia , Animais , Proteína Morfogenética Óssea 2/antagonistas & inibidores , Regeneração Óssea/genética , Diferenciação Celular/efeitos dos fármacos , Células Cultivadas , Técnicas de Cocultura , Citocinas , Fibroblastos/metabolismo , Masculino , Proteínas do Tecido Nervoso/metabolismo , Osteogênese/efeitos dos fármacos , Proteínas/metabolismo , Ratos Wistar
17.
Am J Orthod Dentofacial Orthop ; 155(1): 40-47, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30591164

RESUMO

INTRODUCTION: Orthognathic surgery accelerates orthodontic tooth movement, and tooth movement accelerates with demineralized bone and accelerated bone remodeling. The purpose of this study was to ascertain whether orthognathic surgery induces accelerated bone remodeling. The research design included a human model and an animal model. METHODS: The levels of serum tartrate resistant acid phosphatase-5b (TRAP) and bone alkaline phosphatase (BALP) were measured in 15 patients after sagittal split ramus osteotomy. For the animal study, 18 rabbits were divided into 6 groups: a control group and 5 surgery groups. The rabbits in the surgery groups had osteotomies in the molar regions of the mandible. Changes in bone mass of the anterior mandibles were examined by microcomputed tomography, and changes in osteoblast and osteoclast numbers were analyzed by real-time polymerase chain reaction, hematoxylin and eosin staining, TRAP staining, and alkaline phosphatase staining. RESULTS: In the 15 patients, TRAP-5b increased from 1 to 8 weeks postoperatively, and BALP increased significantly in 2 weeks postoperatively. In the rabbits, the levels of mRNA expression of TRAP were increased at 3 weeks, and matrix metalloproteinase 9 was increased at 4 and 8 weeks, whereas mRNA expression of BALP and bone morphogenetic protein 2 were increased at 4 weeks. Bone loss was detected from 1 week postoperatively and reached the maximum at 3 weeks; and bone mass and mechanical structure did not recoverer to preoperative levels until 8 weeks postoperatively. CONCLUSIONS: These findings show active bone remodeling induced by osteotomy.


Assuntos
Processo Alveolar/fisiologia , Remodelação Óssea/fisiologia , Mandíbula/cirurgia , Osteotomia Mandibular , Adulto , Processo Alveolar/citologia , Análise de Variância , Animais , Biomarcadores/metabolismo , Expressão Gênica , Mentoplastia , Humanos , Mandíbula/citologia , Mandíbula/fisiologia , Modelos Animais , Osteoblastos/fisiologia , Osteoclastos/fisiologia , Osteotomia de Le Fort , Osteotomia Sagital do Ramo Mandibular , Coelhos , Fosfatase Ácida Resistente a Tartarato/genética , Fosfatase Ácida Resistente a Tartarato/metabolismo , Adulto Jovem
18.
Int J Mol Sci ; 19(11)2018 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-30445700

RESUMO

The regeneration of dental tissues is a still an unmet clinical need; in fact, no therapies have been completely successful in regenerating dental tissue complexes such as periodontium, which is also due to the lack of scaffolds that are able to guide and direct cell fate towards the reconstruction of different mineralized and non-mineralized dental tissues. In this respect, the present work develops a novel multifunctional hybrid scaffold recapitulating the different features of alveolar bone, periodontal ligament, and cementum by integrating the biomineralization process, and tape casting and electrospinning techniques. The scaffold is endowed with a superparamagnetic ability, thanks to the use of a biocompatible, bioactive superparamagnetic apatite phase, as a mineral component that is able to promote osteogenesis and to be activated by remote magnetic signals. The periodontal scaffold was obtained by engineering three different layers, recapitulating the relevant compositional and microstructural features of the target tissues, into a monolithic multifunctional graded device. Physico-chemical, morphological, and ultrastructural analyses, in association with preliminary in vitro investigations carried out with mesenchymal stem cells, confirm that the final scaffold exhibits a good mimicry of the periodontal tissue complex, with excellent cytocompatibility and cell viability, making it very promising for regenerative applications in dentistry.


Assuntos
Nanopartículas de Magnetita/química , Periodonto/fisiologia , Regeneração/fisiologia , Tecidos Suporte/química , Processo Alveolar/fisiologia , Animais , Morte Celular , Linhagem Celular , Sobrevivência Celular , Colágeno/química , Cemento Dentário/fisiologia , Cavalos , Camundongos Endogâmicos BALB C , Ligamento Periodontal/fisiologia , Difração de Raios X
19.
Clin Oral Implants Res ; 29 Suppl 18: 6-19, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30306698

RESUMO

OBJECTIVE: To assess the impact of platelet-rich fibrin (PRF) on implant dentistry. The primary focused question was as follows: What are the clinical, histological, and radiographic outcomes of PRF administration for bone regeneration and implant therapy? METHOD: A systematic literature search comprised three databases: MEDLINE, EMBASE, and Cochrane followed by a hand search of relevant scientific journals. Human studies using PRF for bone regeneration and implant therapy were considered and articles published up to December 31, 2017 were included. Eligible studies were selected based on the inclusion criteria. Randomized controlled trials (RCT) and controlled clinical trials (CCT) were included. RESULTS: In total, 5,963 titles were identified with the search terms and by hand search. A total of 12 randomized controlled trials (RCT) met the inclusion criteria and were chosen for data extraction. Included studies focused on alveolar ridge preservation after tooth extraction, osseointegration process, soft tissue management, bone augmentation, bone regeneration after sinus floor elevation and surgical peri-implantitis treatment. Overall, the risk of bias was moderate or unclear. Nine studies showed superior outcomes for PRF for any of the evaluated variables, such as ridge dimension, bone regeneration, osseointegration process, soft tissue healing. Three studies failed to show any beneficial effects of PRF. No meta-analysis could be performed due to the heterogeneity of study designs. CONCLUSIONS: There is moderate evidence supporting the clinical benefit of PRF on ridge preservation and in the early phase of osseointegration. It remains unclear whether PRF can reduce pain and improve soft tissue healing. More research support is necessary to comment on the role of PRF to improve other implant therapy outcomes.


Assuntos
Implantação Dentária Endo-Óssea , Fibrina Rica em Plaquetas , Processo Alveolar/fisiologia , Regeneração Óssea , Implantação Dentária Endo-Óssea/métodos , Humanos , Fibrina Rica em Plaquetas/fisiologia
20.
Arch Oral Biol ; 96: 195-200, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30292055

RESUMO

The alveolar bone has a unique capacity to follow the teeth's movements. It is formed around erupting teeth and their periodontal ligaments: the more the teeth have erupted, the larger the alveolar process. Throughout life the teeth erupt and migrate in an occlusal and mesial direction to compensate for attrition, an evolutionary trait. After tooth extraction, the alveolar process is resorbed to varying degrees. The mandibular alveolar bone mirrors skeletal bone condition. Due to fast bone turnover (which is the fastest in the whole skeleton), low bone mass and increased fracture risk may first be seen here. If a periapical radiograph of the mandibular premolars shows a dense trabeculation with well-mineralized trabeculae and small intertrabecular spaces, it is a reliable sign of normal skeletal bone density (BMD) and low skeletal fracture risk, whereas a sparse trabecular pattern indicates osteopenia and high fracture risk. The bone turnover rate in the mandible is twice that of the maxilla, and may, hypothetically, play a role in the development of osteonecrosis of the jaw (ONJ), which has been found mainly in the mandibular alveolar process?


Assuntos
Processo Alveolar/fisiologia , Mandíbula/fisiologia , Processo Alveolar/metabolismo , Animais , Biomarcadores/metabolismo , Fenômenos Biomecânicos/fisiologia , Osteonecrose da Arcada Osseodentária Associada a Difosfonatos/fisiopatologia , Densidade Óssea/fisiologia , Remodelação Óssea/fisiologia , Humanos , Mandíbula/metabolismo , Osteoporose/fisiopatologia , Erupção Dentária/fisiologia , Extração Dentária , Técnicas de Movimentação Dentária
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