no abstract available

Purpose: Recently, it has been revealed that bone marrow-derived mesenchymal stem cells (MSCs) accelerate the healing of skin wounds. Although the proliferative capacity of MSCs decreases with age, MSCs secrete many growth factors. The present study examined the effect of mesenchymal stem cell-conditioned medium (MSC-CM) on wound healing.
Materials and Methods: The wound-healing process was observed macroscopically and histologically using an excisional wound-splinting mouse model, and the expression level of hyaluronic acid related to the wound healing process was observed to evaluate the wound-healing effects of MSC, MSC-CM, and control (phosphate-buffered saline).
Results: The MSC and MSC-CM treatments accelerated wound healing versus the control group. At 7 days after administration, epithelialization was accelerated, thick connective tissue had formed in the skin defect area, and the wound area was reduced in the MSC and MSC-CM groups versus the control group. At 14 days, infiltration of inflammatory cells was decreased versus 7 days, and the wounds were closed in the MSC and MSC-CM groups, while a portion of epithelium was observed in the control group. At 7 and 14 days, the MSC and MSC-CM groups expressed significantly higher levels of hyaluronic acid versus the control group (P < .05). The expression level of hyaluronic acid was lower at 14 days than at 7 days in all three groups.
Conclusions: Both the MSC and MSC-CM groups accelerated wound healing versus the control group to a similar degree. Accordingly, it is suggested that the MSC-CM contains growth factor derived from stem cells, is able to accelerate wound healing as well as stem cell transplantation, and may become a new therapeutic method for wound healing in the future.

Keywords: cell therapy, human mesenchymal stromal cell, hyaluronic acid, stem cell-derived growth factor, wound healing

Purpose: The zygomatic implant is mainly indicated for the rehabilitation of extremely atrophied maxillae when bone augmentation should be avoided. One drawback of zygomatic implants, which typically pass through the sinus, is initial or late bone resorption around the implant neck, which can result in oroantral communications followed by possible infection of the sinus. To decrease the risk of sinus infection, a modified technique was developed to preserve the integrity of the sinus membrane and to regenerate bone around zygomatic implants using an extended sinus grafting approach.
Materials and Methods: Patients with extremely atrophied maxillae were provided with one to four zygomatic implants in conjunction with sinus grafting, plus conventional auxiliary implants, for immediate support of a provisional full-arch maxillary prosthesis. Definitive prostheses were delivered at 6 months after implant placement. All patients underwent clinical and radiographic examinations at 6 months.
Results: Twenty-two zygomatic and 23 conventional auxiliary implants were placed in 10 patients. The overall 6-month implant survival rate was 90.9% for zygomatic implants and 100% for auxiliary implants placed in the anterior area. Only two minor technical complications were seen, and clinical indicators (including probing pocket depth, keratinized tissue, and plaque and bleeding indices) were good in all patients. A substantial gain of radiographic bone around the zygomatic implants was observed.
Conclusion: The proposed technique led to successful prosthetic function for all patients. With the described technique, exposed implant threads within the maxillary antrum are eliminated and the potential for biologic complications is minimized.

Keywords: atrophic maxilla, dental implants, maxillary sinus, peri-implant bone loss, sinus elevation, zygomatic implant

Purpose: The objective of this study was to histologically evaluate and compare the effects of the permeability of shields on bone augmentation in a rabbit calvarial model.
Materials and Methods: Twelve adult male Japanese white rabbits were used for the study. Each received four titanium cylinders, which were placed into perforated slits made in the outer cortical bone of the calvaria and filled with autologous iliac bone. The tops of the cylinders were randomly covered with the following test materials: (1) uncovered (control), (2) a titanium mesh, (3) an expanded polytetrafluoroethylene (e-PTFE) membrane, or (4) a titanium plate. After 8 weeks, the animals were sacrificed, and ground sections were obtained for histomorphometric analysis.
Results: There was no significant difference in augmented bone volume among all groups. However, the distribution of augmented bone in the cylinders differed among the groups. In the uncovered control, there was significantly less augmented bone in the upper third of the cylinder than in the middle or lower thirds. Findings were similar for the titanium mesh group and the e-PTFE membrane group, with significantly less augmented bone in the upper third than in the middle or lower thirds. In the titanium plate group, there was no significant difference in augmented bone among the upper, middle, and lower thirds. The differences among the upper, middle, and lower thirds of the cylinder were smaller in the order of titanium plate, e-PTFE membrane, titanium mesh, and uncovered control.
Conclusion: The use of low-permeability shields resulted in small differences in the distribution of bone structure in the present bone augmentation model.

Keywords: bone augmentation, bone graft, expanded polytetrafluoroethylene membrane, iliac bone, titanium mesh

Temporomandibular disorders (TMD) are a class of degenerative musculoskeletal conditions associated with morphologic and functional deformities that affect up to 25% of the population, but their etiology and progression are poorly understood and, as a result, treatment options are limited. In up to 70% of cases, TMD are accompanied by malpositioning of the temporomandibular joint (TMJ) disc, termed "internal derangement." Although the onset is not well characterized, correlations between internal derangement and osteoarthritic change have been identified. Because of the complex and unique nature of each TMD case, diagnosis requires patient-specific analysis accompanied by various diagnostic modalities. Likewise, treatment requires customized plans to address the specific characteristics of each patient's disease. In the mechanically demanding and biochemically active environment of the TMJ, therapeutic approaches that can restore joint functionality while responding to changes in the joint have become a necessity. One such approach, tissue engineering, which may be capable of integration and adaptation in the TMJ, carries significant potential for the development of repair and replacement tissues. The following review presents a synopsis of etiology, current treatment methods, and the future of tissue engineering for repairing and/or replacing diseased joint components, specifically the mandibular condyle and TMJ disc. An analysis of native tissue characterization to assist clinicians in identifying tissue engineering objectives and validation metrics for restoring healthy and functional structures of the TMJ is followed by a discussion of current trends in tissue engineering.

Keywords: cartilage, condyle, temporomandibular disorders, temporomandibular joint, temporomandibular joint disc, tissue engineering

Four patients underwent posterior sandwich osteotomy combined with sinus floor grafting using bone morphogenetic protein-2 and other grafting materials. The patients were treated over a period of 4 years. Two to four implants were placed in each site subsequently. Of the 12 implants placed, none failed. Alveolar crest bone levels appeared to be stable over time, with an average vertical gain of about 5 mm. Overall vertical gain, including the sinus graft, exceeded 13 mm in all patients. The procedure appears to hold promise for combined vertical alveolar defects and prominent pneumatization of the posterior maxilla.

Keywords: bone morphogenetic protein-2, combined sinus and alveolar bone grafts, dental implants, posterior maxilla, sandwich osteotomy posterior maxilla, sinus elevation

Oral soft tissue plays an important role in the structure and function of the oral cavity by protecting against exogenous substances, pathogens, and mechanical stresses. Repair of oral soft tissue defects that arise as a result of disease, trauma, or congenital abnormalities is often accomplished via transplantation or transfer of autologous mucosal tissue. However, this method of treatment can be complicated by the relatively small amount of autologous mucosal tissue that is available, as well as by the morbidity that may be associated with the donor site and patient reluctance to have oral (eg, palatal) surgery. To circumvent these problems, clinicians have turned to the fields of tissue engineering and regenerative medicine to develop acellular and cellular strategies for regenerating oral soft tissue. This review focuses on the efficacy and safety of cell-based investigational approaches to the regeneration of oral soft tissue.

Keywords: cellular therapy, oral soft tissue, regeneration

Purpose: The present study tested a recently introduced bone substitute material (BSM) with a novel structure to determine its osteoinductive and osteoconductive properties in vitro and in vivo. The specific aims were to determine the microstructure of the as-manufactured BSM, as analyzed with scanning electron microscopy, and to characterize different cellular interactions.
Materials and Methods: Human bone marrow stromal cells were cultured in the presence of the BSM. In vitro, attachment of osteoblastlike cells (SAOS-2) to the BSM was observed with the scanning electron microscope. The expression of genes related to osteogenic differentiation (alkaline phosphatase, bone sialoprotein, type I collagen, and osteocalcin) was determined by reverse-transcriptase polymerase chain reaction. In vivo, bone formation was examined with a murine model of ectopic bone formation through histology and computed tomographic scanning by using tissue-engineered constructs with the BSM and ovine bone marrow stromal cells.
Results: Early cellular attachment could be detected as early as 6 hours. Cellular morphology developed in the following 66 hours toward a starlike appearance. Human bone marrow stromal cells cultured in the presence of the BSM showed no reduction in their viability. Osteocalcin was up-regulated during cell culturing, demonstrating an osteoinductive effect of BSM. Histologic and computed tomographic analyses showed the formation of new bone surrounding BSM particles, and a vascular meshwork was observed in the porosity of the particles.
Conclusion: The analyzed bone substitute of synthetic origin presented osteoinductive properties that may exert a differentiative stimulus upon osteoprogenitor cells. The tested material allowed cellular adhesion of osteoblastlike cells and, following tissue construct implantation in vivo, supported the formation of new bone.

Keywords: beta-tricalcium phosphate, bone augmentation, bone marrow stromal cells, ectopic bone formation, gene expression, hydroxyapatite, reverse-transcriptase polymerase chain reaction

Purpose: To increase the understanding of the applicability of biomaterials and growth factors in enhancing stem cell-based bone regeneration modalities, this study evaluated the effects of enamel matrix derivative (EMD) and recombinant human transforming growth factor-beta (rhTGF-ß) on osteoblastic differentiation of human bone marrow mesenchymal stem cells (hBMSCs) as well as human periodontal ligament stem cells (hPDLSCs).
Materials and Methods: hBMSCs and hPDLSCs were obtained, and identification of stem cell surface markers was performed according to the criteria of the International Society for Cellular Therapy. Each group of stem cells was separately treated with a serial dilution of EMD (10, 50, and 100 µg/mL) or rhTGF-ß (10 ng/mL). Osteoblastic differentiation was examined through in vitro matrix mineralization by alizarin red staining, and mRNA expression of osteopontin and osteonectin was determined by quantitative reverse-transcriptase polymerase chain reaction. hPDLSCs were further assessed for osteocalcin mRNA expression. Stem cells cultured in osteogenic medium were employed as a standard positive control group.
Results: In none of the experimental groups were bone-related mRNAs detected subsequent to treatment with EMD for 5, 10, and 15 days. Alizarin red staining on day 21 was negative in EMD-treated BMSC and PDLSC cultures. In rhTGF-ß-supplemented BMSC culture, expression of osteonectin mRNA was demonstrated on day 15, which was statistically comparable to the positive control group. Nevertheless, extracellular matrix mineralization was inhibited in both groups of stem cells.
Conclusions: Within the limitations of this study, it could be concluded that EMD with a concentration of 10, 50, or 100 µg/mL has no appreciable effect on osteoblastic differentiation of BMSCs and PDLSCs. Application of rhTGF-ß increased osteonectin mRNA expression in BMSCs. This finding corroborates the hypothesis that TGF-ß might be involved in early osteoblastic maturation.

Keywords: bone marrow stem cell, enamel matrix derivative, periodontal ligament stem cell, transforming growth factor

no abstract available

no abstract available