The Risk of Osseointegration in the Coronavirus Disease 19 Pandemic.

ABSTRACT: Coronavirus disease 19 (COVID-19) is associated with respiratory complications but also with alterations on bone metabolism. Coronavirus disease 19, therefore, might be a risk factor for osseointegration. Recent studies suggest that severe acute respiratory syndrome coronavirus 2 is related with bone abnormalities mainly for act via renin-angiotensin system. This report aims to list the bone alterations caused by coronavirus disease 19 and the possible consequences on the peri-implant bone healing. The current data add to the accumulating knowledge that coronavirus disease 19 may negatively impact the osseointegration and it requires further research.

Central giant cell granuloma in pediatric maxilla: surgical management.

Central giant cell granuloma (CGCG) is an intraosseous lesion consisting of fibrous cellular tissue that contains multiple foci of hemorrhage, multinucleated giant cells, and occasional trabeculae of woven bone. An 8-year-old boy presented himself complaining of a painless swelling in the left maxilla that had started 1 year. Computed tomography (CT) scan confirmed a poorly defined multilocular radiolucent lesion in the left maxilla crossing the midline. The patient underwent enucleation through an intraoral approach of the lesion. The biopsy revealed multinucleated giant cells in a fibrous stroma. A CT was taken approximately 1 year postoperatively. There was no clinical or radiographic evidence of recurrence. Therefore, surgical treatment of CGCG can be performed, trying to preserve the surrounding anatomic structures, which can be maintained in case the lesion does not show an aggressive clinical behavior, avoiding large surgical defects which are undesirable in children.

Anterior pericranial flap for frontal sinus duct obliteration: is it a valuable resource?

Inappropriate treatments of frontal sinus fractures may lead to serious complications, such as mucopyocele, meningitis, and brain abscess. Assessment of nasofrontal duct injury is crucial, and nasofrontal duct injury requires sinus obliteration, which is often accomplished by autogenous grafts such as fat, muscle, or bone. These avascular grafts have an increased risk of resorption and infection and donor site morbidity. For these reasons, pericranial flap, which is vascular, should be used for frontal sinus obliteration. The pericranial flap presented with less morbidity procedure and has decreased infection rates, which justifies its use in frontal sinus obliteration. This study aimed to report a case of a comminuted frontal sinus fracture with a brief literature review, regarding the use of pericranial flap. The authors report a case of a 23-year-old male subject with a severely comminuted fracture of the anterior and posterior walls of the frontal sinus. The patient was successfully treated by cranialization with frontal sinus duct obliteration, using anterior pericranial flap. The patient was followed up for 16 months with no postoperative complication, such as infection. Pericranial flap is a good resource for frontal sinus duct obliteration because it is a durable and well-vascularized flap, which determines low rates of postoperative complications.

Bone Repair Process in Defects of Diabetic Rats Filled with Autogenous Bone Graft and Covered with Homogenous Bone Matrix Membrane or Polytetrafluoroethylene Membrane.

PURPOSE: To analyze the process of repair of bone defects in diabetic rats filled with autogenous bone and covered with membranes of homogenous bone matrix or expanded polytetrafluoroethylene (ePTFE). MATERIALS AND METHODS: One hundred twenty male rats were divided into two groups: group 1 (IC), without systemic alterations (control), received an intravenous injection of citrate buffer at 0.01 M, pH 4.5; group 2 (IID) (diabetic) received an intravenous injection of streptozotocin (Sigma-Aldrich) dissolved in 0.01 M citrate buffer (pH 4.5) at a concentration of 35 mg/kg. After glycemic control was achieved, the rats were subdivided into three groups: SM (surgical cavity of the left tibia filled with autogenous bone graft, not covered by membrane); MH (surgical cavity filled with autogenous bone graft and covered with homogenous membrane); and MX (surgical cavity filled with autogenous bone graft and covered with synthetic ePTFE membrane). At 10 and 60 days, the defects in the tibiae were analyzed histologically and histometrically. RESULTS: At 10 days, no statistically significant differences were found between the groups. However, the bone tissue of the diabetic group was qualitatively worse than that of the control group. At 60 days, a delay was found in the bone-repair process in wounds covered by the membranes regardless of the systemic state, but the quality of the newly formed bone in the wounds covered by the membranes was better in both groups. At 60 days, the diabetic group treated with homogenous membrane experienced less bone formation when compared with the nondiabetic group, and this difference was statistically significant. Such differences were even greater between the groups treated without the membrane (P < .01). CONCLUSION: The homogenous membrane exhibited excellent biocompatibility and was incorporated into the newly formed bone in later periods, both in diabetic and nondiabetic rats.

Avaliação do reparo ósseo na interface osso/implante em ratas com deficiência de estrógeno tratadas com OPG-Fc humano ou ranelato de estrôncio: análise histométrica, imunoistoquímica, biomecânica, por microtomografia computadorizada e microscopia confocal / Evaluation of bone repair at the bone/implant interface in estrogen deficient rats treated with human opg-fc or strontium ranelate. Histometric, immunohistochemistry, biomechanics, computerized microtomography and confocal microscopy analysis

Objetivo: Avaliar o reparo ósseo periimplantar em ratas submetidas à ovariectomia e tratadas com Ranelato de Estrôncio (625mg/kg/dia) ou OPG-Fc (10mg/Kg/2 vezes por semana). Material e Método: Sessenta e quatro ratas, com peso aproximado de 300 gramas, divididas em 4 grupos experimentais conforme tratamento medicamentoso e análises: SHAM; OVX; OVX/RE; OVX/OPG-Fc. Cada animal recebeu 2 implantes sendo 1 em cada metáfise tibial. A eutanásia foi realizada aos 42 e 60 dias após a instalação dos implantes. Foram realizadas as análises de microtomografia computadorizada (micro CT), biomecânica (torque reverso) histométrica, por microscopia confocal a laser, análise da expressão gênica por PCR em tempo real, histológica e imunoistoquímica. Os resultados histológicos evidenciaram para o grupo OVX-RE aspecto de neoformação óssea melhorada, com trabéculas mais espessas e baixa presença de tecido conjuntivo, comparado ao grupo OVX. Os resultados imunoistoquímicos demonstraram intensa marcação de OPG para o grupo OVX-RE e intensa marcação de RANKL para o grupo OVX. Já a análise por microscopia confocal evidenciou que o grupo OVX-RE obteve marcação superior para vermelho de alizarina comparado aos outros dois grupos (Tukey test ­ P < 0,05). Para os parâmetros BV/TV, Tb.Th, o grupo OVX/RE apresentou os maiores valores em relação aos demais grupos. Para Tb.Sp o grupo OVX/OPG-Fc apresentou o melhor resultado (OVX: p<0,05 e OVX/RE: p>0,05), e Tb.N, houve diferença estatisticamente significante na comparação dos resultados entre os grupos OVX e OVX/OPG-Fc (p<0,05). Para MAR e avaliação dos fluorocromos, OVX/RE mostrou melhor turnover ósseo periimplantar, para AON, o grupo SHAM apresentou os maiores resultados (OVX: p<0,05), e para ELCOI o grupo OVX/RE apresentou os melhores resultados. Concluiu-se que o tratamento com ranelato de estrôncio ou OPG-Fc humano melhora significativamente a reparação óssea periimplantar de ratas osteopênicas por inibição da atividade osteclástica exacerbada, promovendo um equilíbrio entre OPG/RANKL, apresentando essa característica melhorada nos animais tratados com ranelato de estrôncio(AU)

Objectives: Evaluate the peri-implant bone repair in rats submitted to ovariectomy and treated with Strontium Ranelate (625mg/kg/day) or OPG-Fc (10mg/kg/2 times per week). Material and Method: sixty-four rats weighing about 300 grams, they were divided into 4 experimental groups according with the treatment and analysis: SHAM; OVX; OVX/RE; OVX/OPG-Fc. Each animal received 2 implants, 1 in each tibial metaphysis. Euthanasia was performed 42 and 60 days after implant installation. Computed micro-tomography (micro-CT), biomechanical (reverse torque), histometrical, laser confocal microscopy, realtime gene expression (RT-PCR), histology and immunohistochemiscal analysis. The histological results revealed for the OVX-RE group a better bone neoformation with thicker trabeculae and low connective tissue compared to OVX group. The immunohistochemical results showed intense labeling of OPG to the OVX-RE group and intense labeling of RANKL to the OVX group. Confocal microscopy analysis exhibited that the OVX-RE group obtained a greater red alizarin marking compared to the others two groups (Tukey test - p<0.05). For the parameters BV/TV, Tb.Th, the OVX/RE group showed the larger values in relation to the other groups. For Tb.Sp the OVX/OPG-Fc group presented the best result (OVX: p<0.05 and OVX/RE: p> 0.05), and the Tb.N exhibited a statistical significant difference in the combination of results between the OVX and OVX / OPG-Fc groups (p<0.05). For the MAR and fluorochromes evaluation, OVX/RE group showed a better peri-implant bone turnover, for the AON, the SHAM group presented the higher results (OVX: p<0.05), and for the ELCOI, the OVX/RE group presented the best results. It is concluded that the treatment with strontium ranelate or OPG-Fc human improve significantly the peri-implant bone repair of osteopenic rats by inhibiting the exacerbated osteoclast activity, promoting a balance between the OPG/RANKL, it showing this improved characteristic in the animals treated with the strontium ranch(AU)

Uso do copolímero de PLA/PGA no processo de reparo de defeitos ósseos em tíbia de coelhos: análise histomorfométrica / Use of copolymer PLA/PGA in the bone repair process in rabbits tibia defects: histomorphometric analysis

Analisar a influência do copolímero de ácido polilático e poliglicólico (PLA/PGA) associado ou não ao osso autógeno no processo de reparo ósseo, em defeitos críticos criados em tíbia de coelhos, por meio da análise histomorfométrica. Material e Método: Doze coelhos receberam 2 ostectomias em cada tíbia por meio de trefina de 6.1 mm de diâmetro. Os defeitos ósseos críticos foram preenchidos de acordo com os seguintes grupos: coágulo sanguíneo (GC), osso autógeno (GA), PLA/PGA (GP) e PLA/PGA associado ao osso autógeno (GPA). Seis animais por período foram submetidos à eutanásia aos 7 e 30 dias pós-operatórios, para a análise histomorfométrica. Resultados: Aos 7 dias, na comparação entre GC(48,33%), GA(25,67%), GP(4,17%) e GPA(21,5%), notou-se diferença estatisticamente significante (Kruskal-Wallis, p=0,0163), evidenciada na comparação entre os GC e GP (Teste de Dunn, p<0,05). Aos 30 dias, a comparação entre GC(56,17%), GA(61,50%), GP(67,33%) e GPA(50,50%), não mostrou diferença estatisticamente significante (Kruskal-Wallis, p=0,2026). Conclusão: Foi possível concluir, neste modelo experimental, que o copolímero PLA/PGA é um biomaterial com propriedades osteocondutoras e pode ser utilizado de maneira isolada, sem a presença de osso autógeno associado...

To analyze the influence of polylactic/polyglycolic acid copolymer (PLA/PGA) associated or not with autogenous bone in the bone repair process in critical size defects of rabbit tibia through histomorphometric analysis. Methods: Twelve rabbits received 2 osteotomies in each tibia through trephine (6.1 mm diameter). The critical bone defects were filled according to the following groups: blood clot (GC), autogenous bone (GA), PLA / PGA (GP) and PLA / PGA associated with autogenous bone (GP). Six animals were euthanized at 7 and 30 days postoperatively. Results: At 7 days, through of groups comparison GC (48.33 %), GA (25.67 %), GP (4.17 %) and GPA (21.5 %) was observed statistically significant difference (Kruskal-Wallis, p= 0.0163), when compared GC and GP groups (Dunn, p < 0.05). At 30 days, the comparison between GC (56.17 %), GA (61.50 %), GP (67.33 %) and GPA (50.50 %) showed no statistically significant difference (Kruskal-Wallis, p = 0.2026). Conclusion: PLA / PGA copolymer is a biomaterial with osteoconductive properties and can be used isolated without autogenous bone supplementation...