Computerâ Guided Immediate Implant Placement and Predigitally Designed Immediate Provisionalization

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142440/1/cap10007_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142440/2/cap10007.pd

Role of Vascular Endothelial Growth Factor in Bone Marrow Stromal Cell Modulation of Endothelial Cells

One of the fundamental principles that underlies tissue-engineering strategies using cell transplantation is that a newly formed tissue must acquire and maintain sufficient vascularization in order to support its growth. Enhancing angiogenesis through delivery of growth factors is one approach to establishing a vascular network to these tissues. In this study, we tested the potential of bone marrow stromal cells (BMSCs) to modulate the growth and differentiation activities of blood vessel precursors, endothelial cells (ECs), by their secretion of soluble angiogenic factors. The growth and differentiation of cultured ECs were enhanced in response to exposure to BMSC conditioned medium (CM). Enzyme-linked immunosorbent assays demonstrated that both mouse and human BMSCs secreted significant quantities of vascular endothelial growth factor (VEGF) (2.4-3.1 ng/106 cells per day). Furthermore, eliminating the activity of BMSC-secreted VEGF with blocking antibodies completely blocked the CM effects on cultured ECs. These data demonstrate that human BMSCs secrete sufficient quantities of VEGF to enhance survival and differentiation of endothelial cells in vitro, and suggest they may be capable of directly orchestrating angiogenesis in vivo.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63256/1/107632703762687573.pd

Comparative analysis of dental implant treatment outcomes following mandibular reconstruction with double‐barrel fibula bone grafting or vertical distraction osteogenesis fibula: a retrospective study

PurposeThe purpose of this study was twofold: (i) to compare vertical bone height (VBH) after tumor resection through grafting with either a double‐barrel fibula (DBF) technique or vertical distraction osteogenesis of the fibula (VDOF); (ii) to compare the performance of loaded dental implants following either DBF or VDOF with special focus on implant survival, implant success, and bone resorption.Materials and methodsThis retrospective clinical study involved 19 patients who underwent implant placement following DBF (group A, n = 9) or VDOF (group B, n = 10) for mandibular reconstruction from March 2006 to May 2008. Clinical and radiographic assessments, including VBH, modified Plaque Index (mPI), modified Sulcus Bleeding Index (mSBI), and marginal bone level (MBL), were taken for both groups after delivery of the final prostheses and annually thereafter.ResultsNine patients underwent DBF with 24 implants placed and 10 patients underwent VDOF with 27 implants placed for mandibular reconstruction after tumor resection. Overall, all DBF and VDOF procedures were successful for group A and group B. VBH for group A and group B were 20 and 17 mm. There was no statistically significant difference of mSBI scores between group A and group B in the 3‐year follow‐up (P = 0.40). In four cases with eight implants of group A and two cases with three implants of group B, granulomatous soft tissue grew. There was no statistically significant differences of MBL between group A and group B in the 3‐year follow‐up (p = 0.736). The cumulative survival and success rates of implants for group A were 100% and 87.5%, and for group B were 100% and 85.2% in 3‐year follow‐up, respectively.ConclusionsOn the basis of the study of 19 patients who received a total of 51 implants, reconstruction of the mandible with DBF flap or VDOF flap, combined with dental implant therapy, was considered a predictable option. Compared with implants placed in VDOF bone, implants placed in DBF bone had a relative higher incidence of associated gingival inflammation. The DBF bone seems more resistant to peri‐implant resorption processes than VDOF bone during functional loading.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110599/1/clr12300.pd

Implant success remains high despite grafting voids in the maxillary sinus

ObjectivesGiven that the nature and presence of voids present within grafted sinuses following maxillary sinus elevation procedures were not known, nor was the contribution of these factors to implant success, the purpose of this study was to investigate these parameters and their relationship to implant success.Materials and MethodsThis study evaluated data from 25 subjects who had a lateral window maxillary sinus augmentation procedure. Cone‐beam computed tomography (CBCT) was performed at baseline and 4 months after surgery. CBCT images were used to evaluate grafted sites prior to implant placement. Using CBCT images, three examiners independently measured bone‐grafted areas (BG), void areas (V), and percentage of void areas (V%) from six different sections within grafted sites. The six sections were defined as a cross‐sectional (CS) midpoint, CS mesial point, CS distal point, horizontal section (HS) low point, HS midpoint, and HS high point. Implant success was also determined.ResultsThe calculated V% (V/BG) for the CS midpoint, CS mesial point, CS distal point, HS low point, HS midpoint, and HS high point were 5.30 ± 6.67%, 5.79 ± 8.51%, 6.67 ± 7.12%, 2.07 ± 2.56%, 5.30 ± 6.62%, and 4.92 ± 5.17% respectively. Implant success after 6 months of follow‐up approximated 100%.ConclusionsAlthough voids within grafts varied in terms of distribution and size, the V% within the HS low point were significantly smaller compared to those within the CS midpoint and CS distal point, which had the most intra‐subject V%. Thus, more attention should be given to the distal aspect of the sinus when compacting graft materials in the lateral wall sinus augmentation procedure. Implant success was not influenced by the existence of voids as implant success remained high.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110843/1/clr12386.pd

Endothelial cell modulation of bone marrow stromal cell osteogenic potential

In the context of bone development and regeneration, the intimate association of the vascular endothelium with osteogenic cells suggests that endothelial cells (ECs) may directly regulate the differentiation of osteoprogenitor cells. To investigate this question, bone marrow stromal cells (BMSCs) were cultured: in the presence of EC‐conditioned medium, on EC extracellular matrix, and in EC cocultures with and without cell contact. RNA and protein were isolated from ECs and analyzed by reverse transcriptase‐polymerase chain reaction and Western blotting, respectively, for expression of bone morphogenetic protein 2 (BMP‐2). In animal studies, BMSCs and ECs were cotransplanted into severe combined immunodeficient mice on biodegradable polymer matrices, and histomorphometric analysis was performed to determine the extent of new bone and blood vessel formation. ECs significantly increased BMSC osteogenic differentiation in vitro only when cultured in direct contact. ECs expressed BMP‐2, and experiments employing interfering RNA inhibition confirmed its production as contributing to the increased BMSC osteogenic differentiation. In vivo, cotransplantation of ECs with BMSCs resulted in greater bone formation than did transplantation of BMSCs alone. These data suggest that ECs function not only to form the microvasculature that delivers nutrients to developing bone but also to modulate the differentiation of osteoprogenitor cells in vitro and in vivo.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154319/1/fsb2fj042529fje-sup-0001.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154319/2/fsb2fj042529fje.pd

Stem Cells Derived from Tooth Periodontal Ligament Enhance Functional Angiogenesis by Endothelial Cells

In regenerative medicine approaches involving cell therapy, selection of the appropriate cell type is important in that the cells must directly (differentiation) or indirectly (trophic effects) participate in the regenerative response. Regardless of the mode of action of the cells, angiogenesis underlies the success of these approaches. Stem cells derived from tooth tissues, specifically the periodontal ligament of teeth (periodontal ligament stem cells [PDLSCs]), have recently been identified as a good source of multipotent cells for cell therapies. PDLSCs have demonstrated properties similar to mesenchymal stem cells (MSCs), yet, unlike MSCs, their vascular potential has not been previously demonstrated. Thus, the aim of this study was to determine if PDLSCs could modulate angiogenesis. In comparison to MSCs and stem cells derived from tooth pulp tissues (SHEDs), we first determined if PDLSCs released soluble proangiogenic factors with the capacity to induce vessel formation by endothelial cells (ECs). Next, the ability of PDLSCs to modulate angiogenesis was examined through their cotransplantation with ECs in subcutaneous sites of immunocompromised mice. Finally, the stability of the PDLSC-mediated vasculature was determined through evaluation of the maturity and functionality of the vessels formed following PDLSC transplantation. It was determined that PDLSCs produced appreciable levels of vascular endothelial growth factor and basic fibroblast growth factor-2, and additionally, were able to initiate in vitro angiogenesis of ECs comparable to MSC- and SHED-mediated angiogenesis. In vivo cotransplantation of ECs with PDLSCs significantly (>50% increase) enhanced the number of blood vessels formed relative to transplantation of ECs alone. Finally, vessels formed following PDLSC cotransplantation were more mature and less permeable than those formed after transplantation of EC alone. These data demonstrate for the first time that PDLSCs have vascular potential, which could make them a very attractive cell population for utilization in regenerative cell therapies.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140229/1/ten.tea.2013.0512.pd

Autologous Ilium Grafts: Long‐Term Results on Immediate or Staged Functional Rehabilitation of Mandibular Segmental Defects Using Dental Implants after Tumor Resection

BackgroundIt is a challenge for clinicians to restore oral function in patients with segmental defects of the mandible because of tumor extirpation. Dental implant therapy following vascularized autologous ilium grafts is an effective method to restore oral function in patients with mandibular segmental defects.PurposeThe aim of this retrospective study was to investigate the long‐term clinical outcomes of ilium grafts combined with immediate or staged mandibular dental implant therapy to restore craniofacial defects resulting from tumor resection.Materials and MethodsOver a 5‐year period (2000–2004), 32 patients who underwent mandibular segmental resection for tumors were treated with vascularized ilium grafts to augment bone volume. Seventeen patients received phase I therapy (immediate placement of implants), and 15 patients underwent phase II therapy (delayed placement of implants). A total of 110 dental implants were placed in these patients for mandibular restoration of the defective areas. Information regarding implant success and survival rates, marginal bone loss, soft tissue inflammation, complications of prosthesis, and patient satisfaction for the 8 to 12 years following oral reconstruction was obtained from patient records.ResultsAlthough there was mild evidence of bone graft resorption, the vascularized autogenous ilium bone grafts were successful in all patients. The cumulative patient survival and success rate of the implants were 96.4% and 91.8%, respectively. The mean peri‐implant bone resorption ranged from 1.0 to 1.2 mm over the 8‐ to 12‐year follow‐up period. The annual mean number of complications/repairs was from 0.11 to 0.07 per patient during the 8‐ to 12‐year follow‐up. Over 80% of the patients were fully satisfied with their restoration of oral function.ConclusionsThis study demonstrates that reconstruction of mandibular segmental defects because of resection of mandibular tumors using dental implants therapy combined with vascularized autogenous ilium grafts is an effective method to restore oral function.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/112185/1/cid12169.pd

Guided Bone Regeneration Using Injectable Vascular Endothelial Growth Factor Delivery Gel

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141041/1/jper0230.pd

Restoration of Oral Function for Adult Edentulous Patients with Ectodermal Dysplasia: A Prospective Preliminary Clinical Study

BackgroundTherapy with zygomatic implants (ZIs) or conventional implants (CIs) has proven to be an effective method to restore oral function for systemically healthy patients. However, it is still a major challenge to fully restore oral function to edentulous adult patients with ectodermal dysplasia (ED).PurposeThe aim of this study was to determine an effective treatment protocol for restoring oral function using ZIs and CIs to edentulous adult ED patients.Materials and MethodsTen edentulous adult ED patients were treated in this study. The treatment protocol involved the following: (1) bone augmentation in the region of the anterior teeth; (2) placement of two ZIs and four CIs in the maxilla, and four CIs in the mandible; (3) fabrication of dental prosthesis; and (4) psychological and oral education. Following treatment of these patients, implant success rates, biological complications, patient satisfaction, and psychological changes were recorded.ResultsAlthough there was evidence of bone graft resorption in the maxilla, bone augmentation of the mandible was successful in all patients. Nine CIs in the maxilla failed and were removed. All ZIs were successful, and the CIs success rates were 77.50% in the maxilla and 100% in the mandible, with a mean of 88.75%. The mean peri‐implant bone resorption for the CIs ranged from 1.3 ± 0.4 mm to 1.8 ± 0.6 mm, and four cases exhibited gingival hyperplasia in the maxilla and mandible. One hundred percent of the patients were satisfied with the restoration of their oral function, and >50% of the patients exhibited enhanced self‐confidence and self‐esteem.ConclusionsThis study demonstrates that oral function can be restored in edentulous adult ED patients using a comprehensive and systematic treatment protocol involving psychological and oral education, bone augmentation, implant placement, and denture fabrication. Despite these positive outcomes, bone augmentation remains challenging in the anterior region of the maxilla for edentulous adult ED patients.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/115948/1/cid12296.pd

Optimized Cell Survival and Seeding Efficiency for Craniofacial Tissue Engineering Using Clinical Stem Cell Therapy

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135593/1/sct320143121495.pd