1,721,050 research outputs found
Management of a Fractured, Nonremovable Implant: A Clinical Report With a 12-Month Follow-Up
Full text linkAbstract
Implant failures could be due to biological or mechanical factors, which also include fracture of the fixture. The present report presents a case of a single fractured implant placed in the left mandibular molar region. Since the residual portion of the fixture was perfectly osseointegrated with no signs of peri-implantitis, and in direct contact with the roof of the inferior alveolar nerve canal, it was decided to treat the patient with a short implant positioned on top of the fractured, and not removing the fractured implant. Clinical and radiographical follow-up was performed for 12 months after loading. Periimplant soft tissues healing and implant osseointegration were achieved 6 months after implant placement; at the end of the follow-up a periimplant bone remodeling of 0.3 mm was observed. In conclusion, short implants could be taken into consideration as a treatment option in cases of nonremovable implants and sufficient residual bone height
Maxillary sinus augmentation in humans using cortical porcine bone: a histological and histomorphometrical evaluation after 4 and 6 months
Full text linkBackground: Bone substitutes, such as allografts, xenografts, and alloplasts, have been proposed in several augmentation procedures. Purpose: The aim of the present study was a histologic and histomorphometric evaluation of specimens retrieved 4 or 6 months after sinus augmentation using cortical porcine bone augmentation material. Materials and Methods: A total of 77 specimens, retrieved after 4 and 6 months from augmented sinuses, were used in this study. The specimens were processed to be observed under light microscopy. Histomorphometric measurements were presented as means 1 standard deviations. Results: Most of the particles were surrounded by newly formed bone with large osteocyte lacunae. Histomorphometry showed that, after 4months, the newly formed bone represented 28%, marrow spaces 36%, the residual graft material 37%, while, after 6 months, the newly formed bone represented 31%, marrow spaces 34%, while the residual graft material was 37%. Conclusion: The present results show that cortical porcine bone is a biocompatible, osteoconductive biomaterial that ca
Sinus Augmentation with Phycogene Hydroxyapatite: Histological and Histomorphometrical Results after 6 Months in Humans
No full textPeri-implant bone reactions around immediately loaded conical implants with different prosthetic suprastructures: Histological and histomorphometrical study on minipigs
No full textThe aim of this study was to evaluate peri-implant bone reactions around immediately loaded conical implants with metal and acrylic resin prosthetic restorations. Five splinted conical implants were inserted in each hemimandible of six minipigs at the alveolar crest level. Ten implants were inserted in each minipig. All the implants were immediately loaded. The implants were divided into a group with an acrylic resin prosthetic restoration and into another group with a metal prosthetic restoration. No postoperative complications or deaths of the minipigs occurred. All minipigs were killed after 3 months. No implant was lost. A total of 60 implants were retrieved and processed to obtain thin ground sections. Histology and histomorphometry showed the presence of compact, mature bone around all the implants. Bone was in close contact with the implant surface starting from the first or second implant threads. A high quantity of mineralized bone was present around immediately loaded conical, root form implants. No differences in the peri-implant bone response were found in the groups with different prosthetic reconstructions. © 2009 Springer-Verlag
Regenerative properties of collagenated porcine bone grafts in human maxilla: demonstrative study of the kinetics by synchrotron radiation microtomography and light microscopy
No full textObjectives: Recently, it has been reported that heterologous biomaterials, where the collagen matrix is preserved, seem to facilitate blood clotting and the subsequent invasion of repairing and regenerative cells. This study aimed at evaluating the healing of human extraction sockets grafted with a collagenated cortico-cancellous porcine bone (mp3®, OsteoBiol®, Tecnoss®, Giaveno, Italy) by Synchrotron Radiation X-ray microtomography (microCT) and histology in order to have a 3D quantitative characterization over time.
Materials and Methods: Ridge preservation with porcine bone and collagen membrane was performed on 21 patients using a flapless approach and a secondary soft tissue closure. At the time of implant placement, 6 bone samples were harvested, two in the 3-month group, two in the 6-month group, one in the 12-month group post-surgery, and evaluated by microCT and histology.
Results: MicroCT revealed that in the grafted sites there was a greater number of trabeculae, although they appeared thinner than in the control sites (spontaneously healed sockets); these trabeculae homogenously filled the defects, suggesting an improved strength of the socket. Histology showed that over time the amount of biomaterial decreased and the newly formed bone increased, whilst less dense bone with wider marrow spaces was detected in the control sample, supporting Synchrotron findings.
Conclusions: The morphometric data converge to indicate the suitability of porcine bone for the preservation of post-extraction sockets.
Clinical Relevance: The use of mp3 is encouraged to preserve and heal sockets
Bone regeneration with phycogene hydroxyapatite. a pilot histological and histomorphometrical study in rabbit tibia defects
No full textBone regeneration with phycogene hydroxyapatite. a pilot histological and histomorphometrical study in rabbit tibia defect
In vitro analysis with human bone marrow stem cells on titanium disks with different surface topographies
No full textThe aim of this study was to assess how surface topography can induce osteoblast differentiation in mesenchymal stem cells by analyzing the expression levels of bone related genes and mesenchymal stem cells marker. Thirty disk-shaped, commercially pure Grade 2 titanium samples (10 x 2 mm) with 3 different surface topographies (DENTSPLY-Friadent GmbH, Mannheim, Germany) were used in the present study: 10 Ti machined disks (control), 10 Ti sandblasted and acid etched disks (DPS) and 10 sandblasted and acid etched disks at high temperature (Plus). Samples were processed for real time Reverse Transcription-Polymerase Chain Reaction (RT–PCR) analysis.
By comparing machined and Plus disks quantitative real-time RT–PCR showed a significant reduction of the bone related genes osteocalcin (BGLAP) and osteoblast transcriptional factor (RUNX2). The comparison between sandblasted and Plus disks showed a slight induction of all the genes examined (RUNX2, ALPL, COL1A1, COL3A1, ENG, FOSL1, SPP1, and SP7); only the expression of BGLAP remained stable. The present study demonstrated that implant surface topography affects osteoblast gene expression. Indeed, Plus surface produces an effect on PB-hMSCs in the late differentiation stages. The obtained results contribute to the understanding of the molecular mechanism of implant osseointegration, the molecular events related to the differentiation of stem cells into osteoblasts and as a model for comparing dental implants with different surface topography
Bone formation in sinus augmentation procedures using autologous bone, porcine bone, and a 50 : 50 mixture: a human clinical and histological evaluation at 2 months
No full textThe aim of this study was to perform a 2 months clinical and histological comparison of autologous bone, porcine bone, and a 50 : 50 mixture in maxillary sinus augmentation procedures. A total of 10 consecutive patients, undergoing two-stage sinus augmentation procedures using 100% autologous bone (Group A), 100% porcine bone (Group B), and a 50 : 50 mixture of autologous and porcine bone (Group C) were included in this study. After a 2-month healing period, at the time of implant insertion, clinical evaluation was performed and bone core biopsies were harvested and processed for histological analysis. The postoperative healing was uneventful regardless of the materials used for the sinus augmentation procedures. The histomorphometrical analysis revealed comparable percentages of newly formed bone, marrow spaces, and residual grafted material in the three groups. The clinical and histological results of this study indicated that porcine bone alone or in combination with autologous bone are biocompatible and osteoconductive materials and can be successfully used in sinus augmentation procedures. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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