RESUMO

The aim of this study is to validate a minimally invasive surgical procedure to harvest palate periosteum as a source of tissue for mesenchymal stromal/stem cells. We performed a standardized procedure to harvest the palate periosteum in ten subjects, which consisted of a 3 mm disposable punch and a Molt periosteal elevator to harvest a small full-thickness fragment of soft tissue at the hard palate area, between the upper bicuspids, 3 to 4 mm apical to the cement enamel junction. The one-third inner portion was fragmented, and following standard cell culture procedures, the adherent cells were cultured for three passages, after obtaining 70-90% confluence. Cell morphology analysis, flow cytometry analysis, and viability and osteogenic differentiation assays were performed. In all 10 cases, uneventful healing was observed, with no need for analgesic intake. The evaluation of cell morphology showed elongated spindle-shaped cells distributed in woven patterns. A high viability range was verified as well as an immunophenotype compatible with mesenchymal stem cell lineage. The differentiation assay showed the potential of the cells to differentiate into the osteogenic lineage. These results demonstrate that the minimally invasive proposed surgical technique is capable of supplying enough periosteum source tissue for stem cell culture and bone tissue engineering.

RESUMO

The aim of this study was to test whether lyophilized conditioned media from human dental pulp mesenchymal stem cell cultures promote the healing of critical-size defects created in the calvaria of rats. Prior to the surgical procedure, the medium in which dental pulp stem cells were cultured was frozen and lyophilized. After general anesthesia, an 8 mm diameter bone defect was created in the calvaria of twenty-four rats. The defects were filled with the following materials: xenograft alone (G1) or xenograft associated with lyophilized conditioned medium (G2). After 14 or 42 days, the animals were euthanized, and the specimens processed for histologic and immunohistochemical analysis. Bone formation at the center of the defect was observed only in the G2 at 42 days. At both timepoints, increased staining for VEGF, a marker for angiogenesis, was observed in G2. Consistent with this, at 14 days, G2 also had a higher number of blood vessels detected by immunostaining with an anti-CD34 antibody. In conclusion, conditioned media from human dental pulp mesenchymal stem cell cultures had a positive effect on the regenerative process in rat critical-size bone defects. Both the formation of bone and enhancement of vascularization were stimulated by the conditioned media.

RESUMO

The aim of this study was to histologically verify the performance of pulp-derived stem cells used in the pulp-dentin complex regeneration. Maxillary molars of 12 immunosuppressed rats were divided into two groups: the SC (stem cells) group, and the PBS (just standard phosphate-buffered saline) group. After pulpectomy and canal preparation, the teeth received the designated materials, and the cavities were sealed. After 12 weeks, the animals were euthanized, and the specimens underwent histological processing and qualitative evaluation of intracanal connective tissue, odontoblast-like cells, intracanal mineralized tissue, and periapical inflammatory infiltrate. Immunohistochemical evaluation was performed to detect dentin matrix protein 1 (DMP1). In the PBS group, an amorphous substance and remnants of mineralized tissue were observed throughout the canal, and abundant inflammatory cells were observed in the periapical region. In the SC group, an amorphous substance and remnants of mineralized tissue were observed throughout the canal; odontoblasts-like cells immunopositive for DMP1 and mineral plug were observed in the apical region of the canal; and a mild inflammatory infiltrate, intense vascularization, and neoformation of organized connective tissue were observed in the periapical region. In conclusion, the transplantation of human pulp stem cells promoted partial pulp tissue neoformation in adult rat molars.

RESUMO

The aim of this study was to compare the clinical, tomographic, and histological performance of collagenated xenogeneic bone blocks (CXBB) in horizontal bone augmentations for implant placement. Five patients with an absence of the 4 upper incisors and an HAC 3 horizontal bone defect, with a remaining of 3 to 5 mm, underwent a bone-grafting procedure with CXBB (test group [TG], n = 5) and autogenous graft (control group [CG], n = 5), with one type of graft used on the right side and other type on the left side. Changes in bone thickness and density (tomographic evaluation), levels of complications (clinically), and distribution pattern between mineralized and nonmineralized tissue (histomorphometrically) were analyzed. Tomographic analysis showed a horizontal bone increase of 4.25 ± 0.78 mm in the TG and 3.08 ± 0.8 mm in the CG between baseline and 8 months postoperatively (P < .05). The horizontal loss between the day of installation of the blocks and 8 months postoperatively was 1.02 ± 0.39 mm for the TG and 1.10 ± 0.71 mm for the CG (P > .05). With regard to bone density, the TG blocks right after installation had 440.2 ± 89.15 HU, and after 8 months, the region reached 730.7 ± 130.98 HU, representing an increase of 29.05%. For the CG blocks, bone density increased from 1052.2 ± 398.35 HU to 1222.5 ± 453.28 HU, representing an increase of 17.03%. The increase in bone density was significantly higher in the TG (P < .05). Clinically, no cases of exposure of the bone blocks and no failure of incorporation were observed. Histomorphometrically, the percentage of mineralized tissue was lower in the TG than in the CG (48.10% ± 2.88% and 53.53% ± 1.05%, respectively), and the opposite was verified for the levels of nonmineralized tissue (52.79% ± 2.88% and 46.47% ± 1.05%, respectively; P < .05). The use of CXBB achieved higher levels of horizontal gain, with lower bone density and lower levels of mineralized tissue when compared with the use of autogenous blocks.

Assuntos

RESUMO

Background: It is known that a large number of mediators involved in osteogenesis can influence bone development and repair; however, whether these mediators could be used as markers of bone maturity has yet to be determined. Aim: To evaluate the expression of osteocalcin (OC) and Runt-related transcription factor 2 (Runx2) in bone biopsies obtained during the reconstruction of atrophic anterior maxillae using particulate bone xenografts with or without association of autogenous bone marrow aspirate concentrate (BMAC). Materials and Methods: Ten patients were distributed into two groups (n = 5), according to the type of grafting material used: Control group (CG), particulate bone xenograft alone, and test group (TG), particulate bone xenograft combined with BMAC. A bone specimen was removed from the graft area 4 months after grafting, before implant placement. The specimens were processed and submitted to immunohistochemical analysis for detection of OC and Runx2. Histomorphometry was used to ascertain the percentage of stained areas in both groups. The Wilcoxon Mann-Whitney U-Test was used in the statistical analysis (P < 0.05). Results: The immunohistochemical analysis revealed a significantly higher OC expression in the TG than in the CG, namely 27.40 ± 1.34% and 11.40 ± 2.70%, respectively (P < 0.05), and a significantly higher Runx2 expression in the TG than in the CG, namely 2.80 ± 0.84% and 0.40 ± 0.55%, respectively (P < 0.05). Conclusion: The OC and Runx2 expression levels were higher when BMAC was associated with the bone xenograft than when it was not.

RESUMO

BACKGROUND: The vertical increase of the alveolar ridge dimension using allograft or xenograft mixed with autogenous bone graft and covered by a nonabsorbable high-density polytetrafluoroethylene (d-PTFE) membrane is well documented in the literature. PURPOSE: The aim of this study was to assess vital mineralized tissue formation in vertical ridge augmentation (VRA) procedures using autogenous bone chips mixed either with an allograft or a xenograft. METHODS: This prospective clinical trial recruited 16 partially edentulous patients to undergo vertical ridge augmentation in one or more sites, making up a total of 24 samples for histological evaluation. Patients were sequentially stratified into Group A (treated with a freeze-dried bone allograft [FDBA] mixed with autogenous bone) or to Group B (treated with a bovine xenograft mixed with autogenous bone). Histological samples were analyzed according to the biomaterial used for VRA. Histological samples were obtained on the same day of membrane removal and implant placement. RESULTS: Thirty-three implants were placed in 16 sites of regenerated bone via VRA, 13 patients with ridge augmentation in the posterior mandible, and 3 patients with VRA in the anterior maxilla. Group A (FDBA + autogenous) and Group B (xenograft + autogenous) showed a percent vital mineralized tissue (VMT) area of 67.64 ± 16.84 and 60.93 ± 18.25, respectively. A significant difference between the two biomaterials was not observed. CONCLUSION: When mixed with autogenous bone, either allografts or xenografts may provide a successful augmentation. Either mixture could serve as reliable alternative in VRA for obtaining a high percentage of VMT.

Assuntos

RESUMO

Background: The integrity of the protective seal provided by the gingiva in direct contact with the implant surface is one of the main factors involved in the prevention of peri-implantitis. Aim: The aim of this study was to assess the viability of periodontal fibroblasts grown in an osteogenic culture medium in contact with titanium surfaces treated either with acid etching alone or with acid etching + anodizing. Materials and Methods: Periodontal fibroblasts grown in an osteogenic culture medium were distributed in a control group, with cells grown in culture bottles, and two experimental groups, with cells grown in contact with titanium disks measuring 6 mm in diameter. The surface of the disks was subjected to acid etching alone (AEG, n = 25) or to acid etching + anodizing (ANG, n = 25), and then evaluated using scanning electron microscopy (SEM). Cell viability was assessed by the [3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl tetrazolium] bromide test on days 1, 2, 3, 7, and 14 of the cell culture. The Mann-Whitney test was used for the statistical analysis (P < 0.05). Results: The SEM assessment revealed that the surface of AEG specimens had micrometric characteristics, whereas the surface of ANG specimens had nanometric characteristics. No significant difference was observed among the groups regarding cell viability at any of the evaluation time points. Conclusion: The titanium surface treatments tested did not affect the viability of periodontal fibroblasts in an osteogenic culture medium.

RESUMO

OBJECTIVE: To compare two pulp harvesting methods for stem cell expansion, namely, conservative pulpotomy and pulpectomy from exodontia. METHOD: Ten freshly extracted sound third molars from five patients were selected. Five were used in the control group, where pulp harvesting was performed by exodontia and the remaining teeth were used in the test group, where the pulp was harvested by conservative pulpotomy (preserving the tooth). This was a split-mouth design study, where a third molar from one side was randomly allocated into the test group and the contralateral tooth in the control group. After pulp harvesting, the following evaluations were performed: cell morphology, sterility test, immunophenotyping, differentiation assays, first pass live cell counts, time to cryopreservation, and total number of expanded cells at the end of the fourth pass. RESULTS: Regarding morphology, the cells from both groups presented a fibroblastic phenotype. All samples were sterile. Immunophenotyping demonstrated a positive expression for CD105, CD90, and CD73 and negative expression for CD45 in both groups. Differentiation assays were positive for osteogenic and chondrogenic differentiation in both groups. Regarding live cell counts in the first passage, the control group had 95.8% live cells in the total count and the test group 91.2% (p < 0.05). The time required for cryopreservation was equivalent in both groups 51.6 days and 52.6 days, respectively (p > 0.05). The total number of cells at the end of the fourth passage was 5,286,782 and 5,736,862, respectively (p > 0.05). CONCLUSION: These results suggest that adult stem cell harvesting from conservative pulpotomy is as effective as the traditional exodontia-based method.

RESUMO

OBJECTIVES: To analyze the histology and histomorphometry of healing associated with acellular dermal matrix in skin wounds in rabbits. METHODS: Twelve male rabbits were divided into two groups: the control group (CG) and the matrix group (MG). Three skin wounds with a total area of 20 × 20 mm were created on the dorsal region of each animal. Photographic records of the lesions taken over a 21-day period and use of the ImageJ program allowed calculation of the wound contraction rate. The lesions were biopsied on days 3, 14 and 21 for histomorphometric analysis to define the thicknesses of the dermis and epidermis (hematoxylin-eosin) and calculate the densities of type I and type III collagen (picrosirius). RESULTS: No significant difference in the healing rate was found between the groups (p>0.05). The MG presented greater epidermal thickness on day 3 (p<0.05) and on days 14 and 21 (p<0.001). The MG presented greater dermal thickness throughout the study period (p<0.05). The type I collagen density was higher in the MG throughout the study period (p<0.05), and the type III collagen density was higher in the MG on days 3 and 14 (p<0.05) and on day 21 (p<0.001). CONCLUSION: The use of acellular dermal matrix increased the thickness of the dermal and epidermal layers and the amount of type I and III collagen during skin wound healing and did not alter the rate of wound contraction.

Assuntos

RESUMO

The aim of this study was to evaluate the level of mineralized tissue and expression of bone markers in sockets grafted with platelet-rich fibrin and bone marrow aspirate concentrate (BMAC). Patients requiring extraction of one maxillary anterior tooth were randomized into three groups. After tooth extraction, the sockets in the control group (CG) were permitted to fill with blood clot. In the platelet-rich fibrin group (PRFG), after blood processing, the sockets were grafted with PRF plug. In the bone marrow aspirate concentrate combined with platelet-rich fibrin group (BM/PG), after blood and bone marrow processing, the sockets were grafted with a mixture of PRF plug and BMAC. After 6 months, the sites were reopened and bone cores were harvested and prepared for histomorphometric and immunohistochemical evaluation. The following levels were measured: mineralized tissue, expression of RUNX-2, and osteocalcin. Fifteen patients were included in this study. The histomorphometric analysis showed a more pronounced level of mineralized tissue in PRFG and BM/PG (54.20 ± 4.31% and 64.70 ± 6.74%, respectively) when compared with CG (40.60 ± 5.98%) (p = 0.0283 and p = 0.0090, respectively). The expression of RUNX-2 was very low in BM/PG (0.80 ± 0.84%) and absent in CG and PRFG (p = 0.0528). Osteocalcin expression was higher for BM/PG (23.40 ± 1.52%) when compared with CG and PRFG (18.40 ± 2.07% and 16.20 ± 1.92%, respectively) (p = 0.0117 and p = 0.0088, respectively). This preliminary study indicates that clinical use of bone marrow aspirate concentrate, when combined with platelet-rich fibrin as a carrier, might have some potential to increase mineralization in fresh extraction sockets.

Assuntos