Falhas biomecânicas com uso de mini-implante ortodôntico: análise por elementos finitos / Biomechanical failures with the use of orthodontic mini-implants: finite element analysis

Esta tese foi dividida em três partes, sendo que cada uma consistiu estudo independente, com objetivos próprios. Na parte 1, o objetivo foi avaliar a influência do modo de representar a interface osso-OMI (osseointegrada ou não osseointegrada) sobre a previsão do risco de reabsorção óssea peri-implantar. Foram construídos quatro modelos tridimensionais que representaram o OMI inserido em quatro cilindros de osso de densidades crescentes, diferenciados pela espessura do osso cortical (Ct = 0,5; 1,2; 2,0 e 3,0 mm) e pelo módulo de elasticidade do osso trabecular (TE = 0,2; 1,4; 3,0 e 5,5 GPa). Para cada modelo, foram simuladas duas condições de interface osso-OMI: uma que considerava união perfeita entre osso e OMI (osseointegrado) e outra que considerava a possibilidade de movimentos relativos entre eles (não osseointegrado). Uma força horizontal de 2 N foi aplicada na cabeça do OMI, para simular a retração de dentes anteriores. A avaliação do risco de reabsorção óssea peri-implantar foi baseada no critério de falha da deformação principal maior, assumindo um valor crítico de 3.000 strain, tanto para tração quanto para compressão. Os resultados mostraram que, ao simular a interface osso-OMI como perfeitamente unida, o risco de perda de estabilidade do OMI por reabsorção óssea peri-implantar no osso menos denso fica subestimado. Na parte 2, foram novamente representadas as quatro condições de qualidade óssea, mas com modelos que representavam o contorno anatômico dos ossos correspondentes: maxila pouco densa, maxila controle, mandíbula controle e mandíbula muito densa. A AEF foi conduzida para tentar explicar por que os OMIs colocados na maxila apresentam maior taxa de sucesso em relação aos OMI colocados na mandíbula, apesar da melhor qualidade do osso mandibular. Além da força horizontal de 2 N (cenário clínico), foi simulada uma força horizontal de 10 N (condição de sobrecarga) e a interface osso OMI foi simulada como não-osseointegrada em todos os modelos. A avaliação do risco de reabsorção óssea peri-implantar seguiu o mesmo critério da parte 1 e foi também avaliado o risco de falta de estabilidade imediata, baseado no deslocamento intra-ósseo do OMI. Em todos os casos, o pico de deslocamento do OMI ficou muito abaixo do limiar de 50-100 m, o que sugere que a estabilidade primária seria suficiente mesmo no cenário de maxila de baixa densidade sobrecarregada. De acordo com os dados da deformação principal maior, a maxila está mais sujeita a perder sua estabilidade inicial devido à sobrecarga ortodôntica, especialmente na condição de baixa densidade, em que tanto a deformação de tração quanto a de compressão ultrapassaram o limiar de reabsorção óssea patológica. É provável que essa AEF não conseguiu prever o maior risco de falha de OMI em mandíbula de alta densidade porque não simulou as tensões residuais geradas pela inserção do OMI. Portanto, a simulação da inserção do OMI parece essencial para explicar a contradição que motivou esse estudo. Na parte 3, o objetivo foi comparar, através da AEF, o risco de reabsorção radicular inflamatória induzida ortodonticamente (RRIIO) entre duas mecânicas ortodônticas de intrusão (convencional e com mini-implantes), em situações de diferentes níveis de suporte periodontal. Foram construídos quatro modelos de um pré-molar superior inserido na maxila: controle (CTL) e 2, 4 ou 6 mm de perda óssea horizontal (R2, R4 e R6, respectivamente). Uma força de intrusão de 25 cN foi utilizada para as duas mecânicas em estudo. Nos modelos com mini-implante ortodôntico, a força foi dividida entre as faces vestibular e palatina. Nos modelos sem mini-implantes, a força foi aplicada apenas na vestibular. O índice de risco de reabsorção radicular (iRRR) foi calculado dividindo o pico de tensão hidrostática compressiva no ligamento periodontal pela tensão hidrostática dos capilares (4,7 kPa). A mecânica com mini-implante, além de apresentar iRRR sempre menores (CTL 1,2 e 1,4; R2: 1,4 e 1,7; R4: 1,7 e 2,2; R6: 2,4 e 3,2 - para mecânicas com e sem OMI, respectivamente), gerou apenas uma região com tensão hidrostática acima do valor crítico, próxima ao ápice do dente, para todos os modelos. Na mecânica convencional, houve também uma região com tensão hidrostática compressiva acima de 4,7 kPa na região cervical vestibular do modelo com 6 mm de perda óssea horizontal. O uso de mini-implante na intrusão ortodôntica diminuiu o risco de RRIIO em todos os casos simulados e o risco de reabsorção óssea adicional no modelo em que o dente apresentava uma perda óssea horizontal prévia de 6 mm.

Histological Evaluation of the Effect of Alendronate on the Maxillary Bone of Wistar Rats Combined with Orthodontic Movement of Intense Force / Evaluación Histológica del Efecto del Alendronate en el Hueso Maxilar de Ratas Wistar Combinado con Movimiento de Ortodoncia de Fuerzas Intensas

SUMMARY: To evaluate the histological adverse effects of alendronate administered systemically and topically in combination with orthodontic movement by intense force. Thirty-six 24-week-old female Wistar rats, ovariectomized, were used and divided into three groups (n = 12/group): control, locally treated with saline (0.07 ml/kg/week) (group 1) and experimental, treated with alendronic acid systemically (0.07 mg/kg/week) (group 2) and locally (7 mg/kg/week) (group 3). At 14 days, an orthodontic anchor was installed in the right first molar, and a force of 144 cN was applied for 28 days. The samples were processed for histological evaluation. Descriptive statistics, Shapiro-Wilk tests, one-way ANOVA with Bonferroni correction, one-way repeated measures ANOVA and chi-square tests were performed. All tests were statistically significant at p <0.05. The adverse events found in all groups were inflammation and osteoclastic activity. In the bisphosphonate-treated groups, there were statistically significant differences (p = 0.005) in the osteoclastic activity between the two hemiarcates. All rats in group 2 presented paralytic ileus. Compared to local administration, systemic treatment with alendronic acid produces more adverse effects, such as inflammation, fibrinoid necrosis, and osteoclastic activity. During the application of intense forces, it was not possible to show that there is necrosis associated with bisphosphonates.

Evaluar los efectos adversos histológicos del alendronato administrado sistémica y tópicamente en combinación con movimientos ortodóncicos de fuerza intensa. Treinta y seis ratas Wistar hembras de 24 semanas de edad, ovariectomizadas, fueron utilizadas y divididas en tres grupos (n = 12/grupo): control, tratado localmente con solución salina (0,07 ml/kg/semana) (grupo 1) y experimental, tratados con ácido alendrónico por vía sistémica (0,07 mg/kg/semana) (grupo 2) y local (7 mg/kg/semana) (grupo 3). A los 14 días se instaló un anclaje de ortodoncia en el primer molar derecho y se aplicó una fuerza de 144 cN durante 28 días. Las muestras fueron procesadas para evaluación histológica. Se realizó estadística descriptiva, pruebas de Shapiro-Wilk, ANOVA de una vía con corrección de Bonferroni, ANOVA de medidas repetidas de una vía y pruebas de chi-cuadrado. Todas las pruebas fueron estadísticamente significativas con un p <0,05. Los eventos adversos encontrados en todos los grupos fueron inflamación y actividad osteoclástica. En los grupos tratados con bisfosfonatos hubo diferencias estadísticamente significativas (p = 0,005) en la actividad osteoclástica entre los dos hemiarcados. Todas las ratas del grupo 2 presentaron íleo paralítico. En comparación con la administración local, el tratamiento sistémico con ácido alendrónico produce más efectos adversos, como inflamación, necrosis fibrinoide y actividad osteoclástica. Durante la aplicación de fuerzas intensas, no fue posible demostrar que existe necrosis asociada con los bisfosfonatos.

Diferencia en la expresión del ligando de receptor activador para el factor nuclear K B, en tejido tumoral frente a la infección por diferentes patógenos periodontales / Difference in receptor activator of nuclear factor K B expression in tumoral tissue by different periodontal pathogens

La enfermedad periodontal es una de las principales causas de pérdida dentaria. Clínicamente, esta patología, mediada por la desregulación del sistema inmune producto de una disbiosis ocurrida en el surco gingival, inicia con la inflamación de la encía y evoluciona con el daño irreversible de los tejidos que rodean el diente. El hueso alveolar es uno de los tejidos afectados esta patología, esto debido a la activación de osteoclastos por la sobreexpresión de la proteína RANKL en el huésped. El propósito de este trabajo es determinar el nivel de sobreexpresión de RANKL, en un modelo de células tumorales U2OS, frente a la infección con Porphyromonas gingivalis y Prevotella intermedia. Para identificar el nivel de RANKL, se definieron cuatro grupos: Un grupo control, no tratado; Grupo PG, tratado con P. gingivalis; Grupo PI, tratado con P. Intermedia; y un grupo PG+PI, tratado con ambas bacterias. El nivel relativo de la proteína RANKL fue determinado en el sobrenadante y en los extractos celulares de manera independiente, mediante la técnica Western blot. En sobrenadantes, el grupo PG mostró mayores niveles de RANKL comparados con PI (p < 0,05). En extractos celulares los niveles fueron mayores en el grupo PG+PI (p < 0,05). El grupo PI mostró los niveles más bajos de RANKL. La infección polimicrobiana resulta en una mayor expresión de RANKL en células tumorales U2OS, mientras que frente a la infección P. gingivalis, se observó mayor cantidad de RANKL soluble.

SUMMARY: Periodontal disease is one of the main causes of tooth loss. Clinically, this pathology, mediated by the deregulation of the immune system due to a dysbiosis occurred in the gingival sulcus, begins with the inflammation of the gum and evolves with the irreversible damage of the tissues that surround the tooth. Alveolar bone is one of the most affected tissues by this disease, due to the activation of osteoclasts by the upregulation of RANKL in the host. The aim of this study is to determine the increase of RANKL, in a U2OS tumor cells model, inoculated with Porphyromonas gingivalis and Prevotella intermedia. To identify the level of RANKL, four groups were defined: A control group, not treated; PG group, treated with P.gingivalis; PI group, treated with P. intermedia; and a PG+PI group, treated with both bacteria. The relative level of RANKL was determined in the supernatant and cell extracts independently, using the Western blot technique. In supernatants, the PG group showed higher RANKL levels compared to PI (p < 0.05). In cell extracts the levels were higher in the PG+PI group (p < 0.05.). The PI group showed the lowest levels of RANKL.Polymicrobial infection results in a greater expression of of soluble RANKL was observed.

Study of dental arch width in patients with idiopathic condylar resorption / 临床耳鼻咽喉头颈外科杂志

Objective:To investigate the relationship between idiopathic condylar resorption （ICR） and arch width disorder. Methods:Thirty-two patients with ICR and twenty patients without condylar resorption were enrolled according to the same inclusion criteria. They were divided into experimental group and control group. The experimental group was divided into unilateral ICR group and bilateral ICR group according to the affected side of condylar resorption, and then experimental group was divided into subgroups ICR Ⅰ, ICRⅡand ICR Ⅲ according to the degree of condylar resorption. Patients with no condylar resorption were used as a control group. The width of anterior, middle and posterior segments of dental arch on cone beam computed tomography（CBCT） was measured and the two groups of measured values were statistically analyzed. Results:Compared with the control group, the width of maxillary anterior, middle and posterior segments in ICR group was significantly reduced, and the difference was statistically significant（P<0.01）. But the width of mandibular segment was not significantly different from that in control group（P>0.05）. There was no significant difference in the width of anterior, middle and posterior dental arch between subgroups（P>0.05）. Conclusion:Almost all patients with ICR have malocclusion of maxillary and mandibular arch width, but there is no significant correlation between the malocclusion width and the severity of condylar resorption.

Advances on pentraxin 3 in osteoporosis and fracture healing / 中国骨伤

Pentaxin 3 (PTX3), as a multifunctional glycoprotein, plays an important role in regulating inflammatory response, promoting tissue repair, inducing ectopic calcification and maintaining bone homeostasis. The effect of PTX3 on bone mineral density (BMD) may be affected by many factors. In PTX3 knockout mice and osteoporosis (OP) patients, the deletion of PTX3 will lead to decrease of BMD. In Korean community "Dong-gu study", it was found that plasma PTX3 was negatively correlated with BMD of femoral neck in male elderly patients. In terms of bone related cells, PTX3 plays an important role in maintaining the phenotype and function of osteoblasts (OB) in OP state;for osteoclast (OC), PTX3 in inflammatory state could stimulate nuclear factor κ receptor activator of nuclear factor-κB ligand (RANKL) production and its combination with TNF-stimulated gene 6(TSG-6) could improve activity of osteoclasts and promote bone resorption;for mesenchymal stem cells (MSCs), PTX3 could promote osteogenic differentiation of MSCs through PI3K/Akt signaling pathway. In recent years, the role of PTX3 as a new bone metabolism regulator in OP and fracture healing has been gradually concerned by scholars. In OP patients, PTX3 regulates bone mass mainly by promoting bone regeneration. In the process of fracture healing, PTX3 promotes fracture healing by coordinating bone regeneration and bone resorption to maintain bone homeostasis. In view of the above biological characteristics, PTX3 is expected to become a new target for the diagnosis and treatment of OP and other age-related bone diseases and fracture healing.

Regulatory function and mechanism of autophagy on osteoclast / 中国骨伤

Osteoclast (OC) is multinucleated, bone-resorbing cells originated from monocyte/macrophage lineage of cells, excessive production and abnormal activation of which could lead to many bone metabolic diseases, such as osteoporosis, osteoarthritis, etc. Autophagy, as a highly conserved catabolic process in eukaryotic cells, which plays an important role in maintaining cell homeostasis, stress damage repair, proliferation and differentiation. Recent studies have found that autophagy was also involved in the regulation of osteoclast generation and bone resorption. On the one hand, autophagy could be induced and activated by various factors in osteocalsts, such as nutrient deficiency, hypoxia, receptor activator of nuclear factor(NF)-κB ligand(RANKL), inflammatory factors, wear particles, microgravity environment, etc, different inducible factors, such as RANKL, inflammatory factors, wear particles, could interact with each other and work together. On the other hand, activated autophagy is involved in regulating various stages of osteoclast differentiation and maturation, autophagy could promote proliferation of osteoclasts, inhibiting apoptosis, and promoting differentiation, migration and bone resorption of osteoclast. The classical autophagy signaling pathway mediated by mammalian target of rapamycin complex 1(mTORC1) is currently a focus of research, and it could be regulated by upstream signalings such as phosphatidylinositol 3 kinase(PI-3K)/protein kinase B (PKB), AMP-activated protein kinase(AMPK). However, the paper found that mTORC1-mediated autophagy may play a bidirectional role in regulating differentiation and function of osteoclasts, and its underlying mechanism needs to be further ciarified. Integrin αvβ3 and Rab protein families are important targets for autophagy to play a role in osteoclast migration and bone resorption, respectively. In view of important role of osteoclast in the occurrence of various bone diseases, it is of great significance to elucidate the role of autophagy on osteoclast and its mechanism for the treatment of various bone diseases. The autophagy pathway could be used as a new therapeutic target for the treatment of clinical bone diseases such as osteoporosis.

Research progress of bone graft resorption after Latarjet procedure for treatment of recurrent anterior shoulder dislocation / 中国修复重建外科杂志

OBJECTIVE@#To review the research progress of bone graft resorption after Latarjet procedure for the treatment of recurrent anterior shoulder dislocation, and provide a guide for further research on bone graft resorption.@*METHODS@#The relevant literature in recent years was extensively reviewed. The pathogenesis, classification, risk factors, clinical function impact, and management of bone graft resorption after Latarjet procedure for the treatment of recurrent anterior shoulder dislocation were summarized.@*RESULTS@#Bone graft resorption is the common complication after Latarjet procedure for the treatment of recurrent anterior shoulder dislocation. Stress shielding and poor blood supply may contribute to the occurrence of bone graft resorption. The absence of significant preoperative glenoid bone loss, open procedure, earlier graft healing may to be the risk factors for bone graft resorption. Various assessment methods and classification systems are used to evaluate the region and severity of bone graft resorption. Partial resorption may be considered as a natural glenoid remodeling process after the surgery, but severe and complete resorption is proved to be one of the reasons for failed procedures and there is no effective measure to prevent it, except for accepting revision surgery.@*CONCLUSION@#The pathogenesis, risk factors, clinical function impact of bone graft resorption after Latarjet procedure for the treatment of recurrent anterior shoulder dislocation has not been fully elucidated and there is a lack of effective management strategies, so further clinical and basic researches are needed.

Research progress in biomechanics of Bristow-Latarjet procedure for anterior shoulder dislocation / 中国修复重建外科杂志

OBJECTIVE@#To review the research progress of the biomechanical study of the Bristow-Latarjet procedure for anterior shoulder dislocation.@*METHODS@#The related biomechanical literature of Bristow-Latarjet procedure for anterior shoulder dislocation was extensively reviewed and summarized.@*RESULTS@#The current literature suggests that when performing Bristow-Latarjet procedure, care should be taken to fix the bone block edge flush with the glenoid in the sagittal plane in the direction where the rupture of the joint capsule occurs. If traditional screw fixation is used, a double-cortical screw fixation should be applied, while details such as screw material have less influence on the biomechanical characteristics. Cortical button fixation is slightly inferior to screws in terms of biomechanical performance. The most frequent site of postoperative bone resorption is the proximal-medial part of the bone block, and the cause of bone resorption at this site may be related to the stress shielding caused by the screw.@*CONCLUSION@#There is no detailed standardized guidance for bone block fixation. The optimal clinical treatment plan for different degrees of injury, the factors influencing postoperative bone healing and remodeling, and the postoperative osteoarticular surface pressure still need to be further clarified by high-quality biomechanical studies.

Exercise regulates bone metabolism via microRNAs / 生理学报

It has been well documented that exercise can improve bone metabolism, promote bone growth and development, and alleviate bone loss. MicroRNAs (miRNAs) are widely involved in the proliferation and differentiation of bone marrow mesenchymal stem cells, osteoblasts, osteoclasts and other bone tissue cells, and regulation of balance between bone formation and bone resorption by targeting osteogenic factors or bone resorption factors. Thus miRNAs play an important role in the regulation of bone metabolism. Recently, regulation of miRNAs are shown to be one of the ways by which exercise or mechanical stress promotes the positive balance of bone metabolism. Exercise induces changes of miRNAs expression in bone tissue and regulates the expression of related osteogenic factors or bone resorption factors, to further strengthen the osteogenic effect of exercise. This review summarizes relevant studies on the mechanism whereby exercise regulates bone metabolism via miRNAs, providing a theoretical basis for osteoporosis prevention and treatment with exercise.

Osteoimmunology research in rheumatoid arthritis: From single-cell omics approach / 中华医学杂志(英文版)

Cellular immune responses as well as generalized and periarticular bone loss are the key pathogenic features of rheumatoid arthritis (RA). Under the pathological conditions of RA, dysregulated inflammation and immune processes tightly interact with skeletal system, resulting in pathological bone damage via inhibition of bone formation or induction of bone resorption. Single-cell omics technologies are revolutionary tools in the field of modern biological research.They enable the display of the state and function of cells in various environments from a single-cell resolution, thus making it conducive to identify the dysregulated molecular mechanisms of bone destruction in RA as well as the discovery of potential therapeutic targets and biomarkers. Here, we summarize the latest findings of single-cell omics technologies in osteoimmunology research in RA. These results suggest that single-cell omics have made significant contributions to transcriptomics and dynamics of specific cells involved in bone remodeling, providing a new direction for our understanding of cellular heterogeneity in the study of osteoimmunology in RA.

Acro-osteolysis in a Filipino male with Vinyl chloride exposure: A case report

@#Occupational acro-osteolysis pertains to bone resorption of the distal phalanges of the hands and feet among workers with vinyl chloride exposure. We report the case of a Filipino man with osteolysis of the distal phalanges of the hands initially considered to have systemic sclerosis. The patient had gradual shortening of the fingers, thickening of the skin over the extremities, and hypopigmented patches over a span of more than 20 years. His lower extremities presented with non-pitting edema, skin thickening, and neuropathy, without shortening of the digits. Difficulty of ambulation was apparent due to the development of feet inversion. Radiographic findings of the hands and feet included resorption of distal phalanges, erosive and sclerotic changes, and narrowed joint spaces. Other conditions considered were Hansen’s disease, skeletal tuberculosis, and diabetic neuropathic arthropathy, which were eventually ruled out. The final diagnosis was occupational acro-osteolysis secondary to vinyl chloride exposure. The patient underwent serial total contact casting of the bilateral lower extremities to relieve bipedal edema and to reposition the feet. This case emphasizes the significance of investigating a patient’s occupational history and highlights a rare sequela of exposure to a commonly used chemical agent in the manufacture of polyvinyl chloride products.

Minimally invasive techniques for lateral maxillary sinus floor elevation: small lateral window and one-stage surgery-a 2-5-year retrospective study / 国际口腔科学杂志·英文版

This study aimed to introduce a minimally invasive technique for maxillary sinus floor elevation using the lateral approach (lSFE) and to determine the factors that influence the stability of the grafted area in the sinus cavity. Thirty patients (30 implants) treated with lSFE using minimally invasive techniques from 2015 to 2019 were included in the study. Five aspects of the implant (central, mesial, distal, buccal, and palatal bone heights [BHs]) were measured using cone-beam computed tomography (CBCT) before implant surgery, immediately after surgery (T0), 6 months after surgery (T1), and at the last follow-up visit (T2). Patients' characteristics were collected. A small bone window (height, (4.40 ± 0.74) mm; length, (6.26 ± 1.03) mm) was prepared. No implant failed during the follow-up period (3.67 ± 1.75) years. Three of the 30 implants exhibited perforations. Changes in BH of the five aspects of implants showed strong correlations with each other and BH decreased dramatically before second-stage surgery. Residual bone height (RBH) did not significantly influence BH changes, whereas smoking status and type of bone graft materials were the potentially influential factors. During the approximate three-year observation period, lSFE with a minimally invasive technique demonstrated high implant survival rate and limited bone reduction in grafted area. In conclusion, lSFE using minimally invasive techniques was a viable treatment option. Patients who were nonsmokers and whose sinus cavity was filled with deproteinized bovine bone mineral (DBBM) had significantly limited bone resorption in grafted area.

Long-term effectiveness of uncemented allograft-prosthesis composite for reconstruction of bone defects after proximal femur tumor resection / 中国修复重建外科杂志

OBJECTIVE@#To investigate the long-term effectiveness of uncemented allograft-prosthesis composite (APC) for reconstruction of bone defects after proximal femur tumor resection.@*METHODS@#Between June 2007 and March 2014, 21 patients who underwent uncemented APC reconstruction of proximal femur after tumor resection were retrospectively evaluated. There were 9 males and 12 females with an average age of 33.2 years (range, 19-54 years). There were 9 cases of giant cell tumor of bone, 5 cases of osteosarcoma, 4 cases of osteoblastic osteosarcoma, 2 cases of chondrosarcoma, and 1 case of undifferentiated pleomorphic sarcoma. Thirteen cases of benign bone tumors were all classified as stage 3 by Enneking staging; and 8 cases of malignant bone tumors were classified as grade ⅡB in 7 cases and grade ⅡA in 1 case according to the American Joint Committee on Cancer (AJCC) staging system. Among them, 7 patients underwent reoperation after recurrence, and the rest were primary operations; 8 patients presented with pathological fractures. The preoperative Harris hip score (HHS) and American Musculoskeletal Tumor Society (MSTS) score was 40 (30, 49) and 9.1±3.5, respectively. The length of osteotomy was 80-154 mm, with an average of 110 mm. At 1 year after operation and last follow-up, HHS and MSTS scores were utilized to evaluate the function of hip joint; the gluteus medius strength score was used to evaluation of the hip abduction function. Image examinations were taken at 1, 3, 6, 9, and 12 months after operation and every year thereafter to assess the union of allograft-host bone interfaces. Intra- and post-operative complications were also recorded.@*RESULTS@#All patients were followed up 84-163 months (mean, 123.5 months). At 1 year after operation and last follow-up, the HHS and MSTS scores significantly improved when compared with the preoperative scores ( P<0.05). However, there was no significant difference in the HHS score, MSTS score, and gluteus medius strength score between the two time points after operation ( P>0.05). Image examination showed that all allograft-host bone interfaces achieved union after 5-10 months (mean, 7.6 months). At last follow-up, all patients had bone resorption, including 11 severe cases, 4 moderate cases, and 6 mild cases; the bone resorption sites included Gruen 1, 2, and 7 regions. Complications included 10 fractures and 1 prosthetic fracture. Local recurrence occurred in 3 patients and pulmonary metastasis in 3 patients.@*CONCLUSION@#Uncemented APC is a reliable method for the reconstruction of bone defects after proximal femur tumor resection. It has the good long-term effectiveness and possesses obvious advantages in the union at the bone-bone surface.

Avaliação da resposta óssea de uma superfície de implante revestida com odanacatib em ratas ovariectomizadas: estudo experimental in vivo / Evaluation of the bone response of an odanacatib coated implant surface in ovariectomized rats: in vivo experimental study

Atualmente novos princípios ativos de função reabsortiva têm ganhado campo de estudo para avaliar seus mecanismos e comportamento biológico. Com isso, um novo antirreabsortivo, inibidor da catepsina K tem apresentado efeito positivo na osseointegração. Este estudo tem como objetivo avaliar a resposta óssea da superfície de implantes revestida por duplo ataque ácido e Odanacatib (MK-0822) em ratas ovariectomizadas. Neste estudo foram utilizadas ratas (Albinus, Wistar) ovariectomizadas ou sham (placebo). Cinquenta e dois (52) tiveram as superfícies revestidas por duplo ataque ácido e MK-0822 a 0,06 mg/ml através do método biomimético, e 48 implantes foram instalados em tíbias de ratas ovariectomizadas ou sham. Microscopia eletrônica de varredura (MEV) e energia dispersiva de raios-x (EDS) foram realizadas em 4 implantes após tratamento de superfície, para análise da topografia e composição química, além da realização da análise do ângulo de contato em 16 discos de titânio comercialmente puro tratados com as mesmas superfícies. Aos 15 e 40 dias após instalação de implantes (n=6), foi realizada microtomografia computadorizada. Dados quantitativos foram avaliados adotando-se o nível de significância p< 0,05. Além dos resultados topográficos favoráveis para os grupos tratados com MK-0822, os resultados microtomográficos apresentaram diferença estatisticamente significante entre os grupos SHAM e OVX na maioria dos parâmetros (p< 0,05). Ainda assim, os grupos tratados com MK-0822 apresentaram resultado semelhante ou maior, porém sem diferença estatística, em relação ao grupo controle em todos os parâmetros (TV, BV, BV ̸TV, Tb.Sp e Tb.N)(AU)

Currently new active principles of resorptive function have gained field of study to evaluate their mechanisms and biological behavior. Thereby a new anti-absorbent, cathepsin K inhibitor has had a positive effect on osseointegration. This study aims to evaluate the bone response of the surface of implants coated by double acid-etched and Odanacatib (MK-0822) in ovariectomized rats. In this study, either ovariectomized rats (Albinus, Wistar) or sham (placebo) have been used. Fifty-two (52) implants had the surfaces coated with double acid-etched and MK-0822 at 0,06 mg/ml by the biomimetic method and 48 implants were installed on sham or ovariectomized rat tibias. Scanning electron microscopy (SEM) and X-ray dispersive energy (EDS) were performed in 4 implants after surface treatment for analysis of topography and chemical composition, in addition to performing contact angle analysis on 16 commercially pure titanium discs treated with the same surfaces. At 15 and 40 days after implant installation, microcomputer tomography was performed. Quantitative data was evaluated by adopting the significance level of p< 0.05. Besides the favorable topographic results to MK-0822 coated implants group, the microtomographic results presents statistically significant differences between the SHAM and OVX groups at most of the parameters (p< 0,05). Nevertheless, the MK-0822 coated group presents similar or higher values, although without statistic differences related to the control group in all parameters (TV, BV, BV ̸TV, Tb.Sp and Tb.N)(AU)

Preservação alveolar e instalação tardia de implante dentário: relato de caso / Alveolar preservation and late dental implant installation: case report / Preservación alveolar e instalación tardía de implante dental: reporte de caso

Introdução. Decorrente do trauma local, durante a exodontia, ou pela falta de estímulos mastigatórios, a ausência dentária promove respostas biológicas que desencadeiam um processo de reabsorção óssea. A preservação óssea alveolar propõe minimizar a reabsorção óssea alveolar, promovendo maior biodisponibilidade óssea para a reabilitação por implantes dentários. Os implantes dentários são uma modalidade terapêutica eficaz para a reabilitação de ausências dentárias. Objetivo. relatar um caso de reabilitação por implante em alvéolo cicatrizado, após preservação alveolar. Relato de caso. Paciente A.L.L., sexo masculino, 23 anos, compareceu à clínica odontológica da UNIBRA. Ao exame físico observou-se ampla destruição coronária do elemento 25 e, ao exame radiográfico notou-se tratamento endodôntico. O tratamento proposto foi a exodontia minimamente traumática, preservação alveolar com matriz de colágeno e instalação de implante dentário em alvéolo cicatrizado. Discussão. Em desdentados, a falta de estímulos mastigatórios, promove um desequilíbrio no turnover ósseo, desencadeando um processo de reabsorção. A preservação alveolar por matriz de colágeno visa minimizar a reabsorção e fornecer maior biodisponibilidade óssea para a reabilitação por implantes. Conclusão. A preservação alveolar com a matriz de colágeno cumpriu com seu objetivo e, a reabilitação por implante dentário em alvéolo cicatrizado é uma modalidade eficaz na reabilitação de pacientes desdentados... (AU)

Introduction. Due to local trauma, during tooth extraction, or the lack of masticatory stimuli, the absence of teeth promotes biological responses that trigger a process of bone resorption. Alveolar bone promotion minimizes alveolar bone resorption, promoting high bone bioavailability for rehabilitation with dental implants. Dental implants are a treatment modality to edentulous. Objective. Report a case of implant rehabilitation in a healed socket after alveolar preservation. Case report. Patient A.L.L., male, 23 years old, attended the UNIBRA dental clinic. On physical examination, a wide coronary destruction of element 25 was observed and, on radiographic examination, endodontic treatment was noted. The proposed treatment was a minimally traumatic tooth extraction, alveolar preservation with collagen matrix and implant placement in healed sockets. Discussion. In edentulous patients, the lack of masticatory stimuli promotes an imbalance in bone turnover, triggering a resorption process. Alveolar preservation by collagen matrix aims to minimize resorption and provide greater bone bioavailability for implant rehabilitation. Conclusion. Alveolar preservation with collagen matrix fulfilled its objective, and rehabilitation by dental implant in a healed socket is an effective modality in the rehabilitation of edentulous patients... (AU)

Introducción. Por traumatismo local, durante la extracción dentaria, o por falta de estímulos masticatorios, la ausencia de dientes promueve respuestas biológicas que desencadenan un proceso de reabsorción ósea. La preservación ósea alveolar propone minimizar la reabsorción ósea alveolar, promoviendo una mayor biodisponibilidad ósea para la rehabilitación mediante implantes dentales. Los implantes dentales son una modalidad terapéutica eficaz para la rehabilitación de dientes perdidos. Objetivo. reportar un caso de rehabilitación con implantes en un alvéolo cicatrizado después de preservación alveolar. Reporte de un caso. Paciente A.L.L., masculino, 23 años, acudió a la clínica odontológica de la UNIBRA. El examen físico reveló destrucción coronaria extensa del elemento 25 y el examen radiográfico reveló tratamiento endodóntico. El tratamiento propuesto fue extracción dental mínimamente traumática, preservación alveolar con matriz de colágeno y colocación de implante dental en alvéolo cicatrizado. Discusión. En pacientes edéntulos, la falta de estímulos masticatorios promueve un desequilibrio en el recambio óseo, desencadenando un proceso de reabsorción. La preservación alveolar mediante matriz de colágeno tiene como objetivo minimizar la reabsorción y proporcionar una mayor biodisponibilidad ósea para la rehabilitación con implantes. Conclusión. La preservación alveolar con matriz de colágeno cumplió su objetivo, y la rehabilitación mediante implante dental en un alvéolo cicatrizado es una modalidad eficaz en la rehabilitación de pacientes edéntulos... (AU)

Viabilidade de fibroblastos do ligamento periodontal estimulados com sobrenadante necrótico de células de polpa dental in vitro / Viability of periodontal ligament fibroblasts stimulated with necrotic supernatant from dental pulp cells in vitro

As células necróticas são capazes de induzir a instalação de processos inflamatórios importantes, mesmo em ambientes estéreis, e o papel de remanescentes necróticos pulpares ainda não é conhecido na periodontite apical. O objetivo deste estudo foi investigar a capacidade de modulação in vitro de fibroblastos do ligamento periodontal (FLP) pelo sobrenadante necrótico (SN) de polpa dental. Cultura de fibroblastos de polpa dental (FPD) (n=1) e de ligamento periodontal (n=1) foram obtidas a partir do biobanco. Os FPDs passaram por ciclos de congelamento/descongelamento e o SN submetido a diluições 1/2, 1/10 e 1/20. Os FLPs foram estimulados com o SN de FPD. Para avaliar se o SN interfere na viabilidade celular do FLP foi realizado o ensaio de alamarBlue nos períodos de 24h, 48h e 72h. Nos grupos 24h, 48h e 72h não se observou diferença estatisticamente significativa. Porém, foi notado que no grupo de 72h o tratamento com SN resultou em uma maior ativação celular nas concentrações 1/10 e 1/20 em relação ao controle (p<00,5). O ensaio de MTT avaliou o efeito do SN na viabilidade celular do FLP. No grupo de 24h o SN resultou em uma ativação celular expressiva nas concentrações 1/2, 1/10 e 1/20 em relação ao controle. Nos grupos 48h e 72h não houve diferença estatisticamente significativa (p< 0,05). Os FLPs foram tratados com SN de FPD para avaliar os efeitos da produção de citocinas. A produção de OPG se apresentou maior no grupo com diluição 1/2 em comparação com as demais (p<0,05). A IL-6 apresentou-se aumentada no grupo com menor diluição e reduzida nos grupos com SN mais diluído (p<0,05). A expressão de CCL2 demonstrou-se menor nos grupos com diluição 1/10 e 1/20 (p<0,05). Diante desses resultados, observou-se que o sobrenadante de fibroblastos de polpa dental foi capaz de ativar células de ligamento periodontal in vitro modulando a produção de OPG, IL-6 e CCL2 de forma diluição-dependente.

Revisión sistemática de los efectos de microvibración de baja magnitud alta frecuencia en osteocitos cultivados / Systematic review of the effects of low intensity high frequency microvibration on osteocytes cultivated

Introducción: El hueso, reservorio de minerales y moléculas orgánicas, es un tejido dinámico que detecta y se adapta a las cargas mecánicas de los órganos y tejidos del cuerpo, el cual mantiene la estructura ósea del esqueleto durante el crecimiento y a través de la vida del ser humano. Las células óseas son sensibles a las cargas mecánicas y microvibra- ciones que recibe el esqueleto. Objetivo: El propósito de este estudio fue realizar una revisión sistemática acerca de los efectos que ejerce la microvibración de alta frecuencia-baja intensidad, en osteocitos cultivados in vitro sobre la síntesis de factores solubles, con el propósito de entender si la microvibración tiene influencia en la aceleración del movimiento dentario. Material y métodos: Se realizó una búsqueda de artículos de revisión de osteocitos y otras células óseas in vitro, a través de la estrategia PICO (Paciente, Intervención, Comparación, Resultado [Outcome]), con el empleo de palabras clave como: «os- teocitos¼, «microvibración¼, «remodelación¼, «osteoclastogénesis¼, «citocinas¼ y «osteoblastos¼. Se estructuró por medio de PRISMA (informe de revisiones sistemáticas y meta-análisis). La captación de datos finales se hizo por medio del método de puntuación de calidad Jadad y Cochrane (modelo de correlación) como herramientas para evaluar el riesgo de sesgo de cada uno de los artículos. Se incluyeron 11 artículos con alta calidad metodológica. Resultados: La mayoría de los experimentos in vitro demostraron que la microvibración tuvo un aumento estadísticamente significativo en la proliferación y dife- renciación de las células madre mesenquimales (MSC), en osteoblastos (MC3T3-E1), en la expresión de proteínas para inducir osteogénesis y en los osteocitos (MLO-Y4). Asimismo, sobrerregularon la expresión de osteoprotegerina (OPG), prostaglandina (PGE2) y óxido nitroso (NO) al alterar y regular los factores solubles como las citocinas, factores de crecimiento y quimiocinas, de las demás células, además de mostrar una disminución en la actividad de los osteoclastos (RAW246.7) en la resorción ósea. Conclusión: La microvibración induce remodelación ósea. Los osteocitos son sensibles a los estímulos mecánicos y producen factores solubles para inducir la remodelación ósea, razón por la cual se emplea la microvibración como una terapia innovadora y prometedora, no invasiva y no farmacológica en la estimulación de la formación ósea de la superficie del hueso (AU)

Implantes imediatos, e seus defeitos peri-implantares (GAP) preenchidos com o uso de biomateriais sintéticos / Implants, and their peri-implant defects (GAP) filled with the use of synthetic biomaterials

A colocação de implantes osseointegráveis requer volume ósseo adequado, porém, a extração de dentes leva a diferentes padrões de remodelaç ão e reabsorção óssea. A reabsorção do rebordo alveolar tem sido considerada uma consequência inevitável da extração dentária e pode ser um problema significativo em Implantodontia. Após a extração dentária, mesmo com a instalação de implantes imediatos, o sítio desdentado do processo alveolar sofre substancial modelagem óssea, com a diminuiç ão das dimensões da crista alveolar. Após a inserção de um implante em um local de extração fresco, um defeito marginal (GAP) ocorre, frequentemente, entre o rebordo e a superfície do implante, A fim de superar esse problema e para facilitar a formaç ão de osso no defeito marginal, vários processos de enxerto têm sido utilizados, associados ou não ao uso de membranas de barreira, bem como diversos tipos de substitutos ósseos que podem ser utilizados para tal procedimento. Esse trabalho tem por objetivo revisar e discutir a literatura relacionada ao uso de biomateriais sintéticos para preenchimento desses defeitos que se formam ao redor de implantes instalados em alvéolos frescos. No entanto, ainda não existe um biomaterial ideal que possua todas as pro- priedades desejáveis. Além disso, o volume de osso residual deve ser avaliado antes da extração de dentes, de modo que os cirurgiões possam utilizar técnicas diferentes para preservar o osso alveolar.

Relationship between the Height of Alveolar Bone Resorption and Sex and Age in Adolescents / 法医学杂志

OBJECTIVES@#To explore the relationship between the height of alveolar bone resorption and sex and age in the adolescent dentition.@*METHODS@#Multi-slice computed tomography (MSCT) was used to measure the height of alveolar bone resorption at labial, lingual, mesial and distal sites of teeth in 149 adolescents aged from 10 to 20 years. SPSS 25.0 software was used to analyze the relationship between the height of alveolar bone resorption and sex and age.@*RESULTS@#There was no significant difference in the height of alveolar bone resorption between sex (P>0.05). The height of alveolar bone resorption was positively correlated with age in all types of teeth. The model constructed by combining the alveolar bone resorption height data of four sites (y=2.569x1+3.106x2+4.108x3+1.451x4-0.082, R2max=0.756)had a better ability to infer age than that of combining two sites (y=5.942x1+4.489x2+0.612, R2max=0.706) and a single site (R2max=0.638).@*CONCLUSIONS@#The height of alveolar bone resorption is positively correlated with the age of adolescents. The combination of four sites has a stronger ability to infer the relationship between the height of alveolar bone resorption and age in adolescents and has higher accuracy in practical application.

Host defense peptides clavanins A and MO reduce in vitro osteoclastogenesis

Aim: Several systemic diseases, such as periodontitis and apical periodontitis, can cause extensive bone resorption. Host defense peptides may have the potential for the development of novel therapies for the bone resorption process. This study evaluated the potential of host defense peptides clavanins A, MO, and LL-37 in in vitro osteoclastogenesis. Methods: RAW 264.7 cultures were stimulated with recombinant of receptor activator of nuclear factor kappa B ligand in the presence of different tested concentrations of host defense peptides, besides calcium hydroxide and doxycycline. Cellular viability, nitric oxide production, and a number of differentiated osteoclast-like cells were also evaluated. Results: Results showed that none of the substances were cytotoxic, except for 128 µg.mL-1 of doxycycline after 3 days. Host defense peptides, calcium hydroxide, and doxycycline did not interfere in nitric oxide production or downregulated it. An exception was observed in the presence of 2 µg.mL-1 of doxycycline, in which nitric oxide production was up-regulated. All host defense peptides were capable of reducing osteoclast-like cell differentiation. Conclusion: Host defense peptides clavanins A and MO demonstrated to be potential suppressors of osteoclastogenesis in vitro without interfering in cellular viability and nitric oxide production. These promising results need to be further analyzed in in vivo models of bone resorption