Retracted: Bone neoformation of a novel porous resorbable Si-Ca-P-based ceramic with osteoconductive properties: physical and mechanical characterization, histological and histomorphometric study

2016 ◽  
Vol 27 (11) ◽  
pp. 1368-1375 ◽  
Author(s):  
Piedad N. De Aza ◽  
Jose E. Mate-Sanchez de Val ◽  
Carmen Baudin ◽  
Carlos Perez Albacete-Martínez ◽  
Antonio Armijo Salto ◽  
...  
Author(s):  
Yaniv Mayer ◽  
Ofir Ginesin ◽  
Hadar Zigdon-Giladi

Implant primary stability, which depends mainly on the amount and quality of bone, is important for implant survival. Socket preservation aims to reduce bone volumetric changes following tooth extraction. This animal study aims to examine whether preserving a ridge by using xenograft impairs the primary stability of the implant. Eighteen artificial bone defects were prepared in four sheep (5mmØ and 8mm length).  Defects were randomly grafted with xenografts: Bio-Oss (BO), Bioactive Bone (BB), or left for natural healing (control). After 8 weeks, bone biopsy was harvested and dental implants installed. During installation, peak insertion torque (IT) was measured by hand ratchet, and primary stability by the Osstell method. Histomorphometric analysis showed a higher percentage of new bone formation in the naturally healed defects compared to sites with xenograft (control 68.66 ± 4.5%, BB 48.75 ± 4.34%, BO 50.33 ± 4.0%). Connective tissue portion was higher in the BO and BB groups compared to control (44.25 ± 2.98%, 41 ± 6%, and 31.33 ± 4.5, p<0.05, respectively). Residual grafting material was similar in BO and BB (7 ± 2.44%, 8.66 ± 2.1 %, respectively). Mean IT and ISQ values were not statistically different among the groups. A positive correlation was found between IT and ISQ (r=0.65, p=0.00). In conclusion, previously grafted defects with xenograft did not influence primary stability and implant insertion torque in delayed implant placement. These results may be attributed to a relatively high bone fill of the defect (~50%) two months after grafting.


2018 ◽  
Author(s):  
Devon Jakob ◽  
Le Wang ◽  
Haomin Wang ◽  
Xiaoji Xu

<p>In situ measurements of the chemical compositions and mechanical properties of kerogen help understand the formation, transformation, and utilization of organic matter in the oil shale at the nanoscale. However, the optical diffraction limit prevents attainment of nanoscale resolution using conventional spectroscopy and microscopy. Here, we utilize peak force infrared (PFIR) microscopy for multimodal characterization of kerogen in oil shale. The PFIR provides correlative infrared imaging, mechanical mapping, and broadband infrared spectroscopy capability with 6 nm spatial resolution. We observed nanoscale heterogeneity in the chemical composition, aromaticity, and maturity of the kerogens from oil shales from Eagle Ford shale play in Texas. The kerogen aromaticity positively correlates with the local mechanical moduli of the surrounding inorganic matrix, manifesting the Le Chatelier’s principle. In situ spectro-mechanical characterization of oil shale will yield valuable insight for geochemical and geomechanical modeling on the origin and transformation of kerogen in the oil shale.</p>


2017 ◽  
Vol 5 (3) ◽  
pp. 8
Author(s):  
KUMAR DINESH ◽  
KAUR ARSHDEEP ◽  
AGGARWAL YUGAM KUMAR ◽  
UNIYAL PIYUSH ◽  
KUMAR NAVIN ◽  
...  

Author(s):  
Erick Ramon Medeiros do Nascimento ◽  
Evans Ferreira ◽  
Daniel Freitas Freire Martins ◽  
Ana Batista ◽  
Fernanda Beatriz Aires de Freitas

Author(s):  
Alexandre Luiz Pereira ◽  
Rafael Oliveira Santos ◽  
DOINA BANEA ◽  
Álisson Lemos

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