Bacterial cellulose matrix and acellular dermal matrix seeded with fibroblasts grown in platelet-rich plasma supplemented medium, compared to free gingival grafts: a randomized animal study.

PURPOSE: Mucogingival defects (MGDs), such as dental root recessions, decreased vestibular depth, and absence of keratinized tissues, are commonly seen in dental clinics. MGDs may result in functional, aesthetic, and hygienic concerns. In these situations, autogenous soft tissue grafts are considered the gold-standard treatment. This study compares the healing process of free gingival grafts (FGGs) to bacterial cellulose matrix (BCM) and human acellular dermal matrix (ADM) seeded with fibroblasts from culture supplemented with platelet-rich plasma in a rat model. METHODS: Surgical defects were made in rats, which received the following treatments in a randomized manner: group I, negative control (defect creation only); group II, positive control (FGG); group III, BCM; group IV, BCM + fibroblasts; group V, ADM; and group VI, ADM + fibroblasts. Clinical, histological, and immunological analyses were performed 15 days after grafting. Clinical examinations recorded epithelium regularity and the presence of ulcers, erythema, and/or edema. RESULTS: The histological analysis revealed the degree of reepithelization, width, regularity, and presence of keratin. The Fisher exact statistical test was applied to the results (P<0.05). No groups showed ulcers except for group I. All groups had regular epithelium without erythema and without edema. Histologically, all groups exhibited regular epithelium with keratinization, and myofibroblasts were present in the connective tissue. The groups that received engineered grafts showed similar clinical and histological results to the FGG group. CONCLUSIONS: Within the limitations of this study, it was concluded that BCM and ADM can be used as cell scaffolds, with ADM yielding the best results. This study supports the use of this technical protocol in humans.

Enhanced bone tissue regeneration with hydrogel-based scaffolds by embedding parathyroid hormone in mesoporous bioactive glass.

OBJECTIVES: To evaluate hydrogel-based scaffolds embedded with parathyroid hormone (PTH)-loaded mesoporous bioactive glass (MBG) on the enhancement of bone tissue regeneration in vitro. MATERIALS AND METHODS: MBG was produced via sol-gel technique followed by PTH solution imbibition. PTH-loaded MBG was blended into the hydrogels and submitted to a lyophilisation process associated with a chemical crosslinking reaction to the production of the scaffolds. Characterisation of the MBG and PTH-loaded MBG scaffolds, including the scanning electron microscope (SEM) connected with an X-ray detector (EDX), Fourier transform infrared (FTIR), compression strength, rheological measurements, swelling and degradation rates, and PTH release analysis, were performed. Also, bioactivity using simulated-body fluid (SBF), biocompatibility (MTT), and osteogenic differentiation analyses (von Kossa and Alizarin Red stainings, and µ-computed tomography, µCT) of the scaffolds were carried out. RESULTS: SEM images demonstrated MBG particles dispersed into the hydrogel-based scaffold structure, which was homogeneously porous and well interconnected. EDX and FTIR revealed large amounts of carbon, oxygen, sodium, and silica in the scaffold composition. Bioactivity experiments revealed changes on sample surfaces over the analysed period, indicating the formation of carbonated hydroxyapatite; however, the chemical composition remained stable. PTH-loaded hydrogel-based scaffolds were biocompatible for stem cells from human-exfoliated deciduous teeth (SHED). A high quantity of calcium deposits on the extracellular matrix of SHED was found for PTH-loaded hydrogel-based scaffolds. µCT images showed MBG particles dispersed into the scaffolds' structure, and a porous, lamellar, and interconnected hydrogel architecture. CONCLUSIONS: PTH-loaded hydrogel-based scaffolds demonstrated consistent morphology and physicochemical properties for bone tissue regeneration, as well as bioactivity, biocompatibility, and osteoinductivity in vitro. Thus, the scaffolds presented here are recommended for future studies on 3D printing. CLINICAL RELEVANCE: Bone tissue regeneration is still a challenge for several approaches to oral and maxillofacial surgeries, though tissue engineering applying SHED, scaffolds, and osteoinductive mediators might help to overcome this clinical issue.

Effect of dexamethasone as osteogenic supplementation in in vitro osteogenic differentiation of stem cells from human exfoliated deciduous teeth.

In in vitro culture systems, dexamethasone (DEX) has been applied with ascorbic acid (ASC) and ß-glycerophosphate (ßGLY) as culture media supplementation to induce osteogenic differentiation of mesenchymal stem cells. However, there are some inconsistencies regarding the role of DEX as osteogenic media supplementation. Therefore, this study verified the influence of DEX culture media supplementation on the osteogenic differentiation, especially the capacity to mineralize the extracellular matrix of stem cells from human exfoliated deciduous teeth (SHED). Five groups were established: G1-SHED + Dulbecco's Modified Eagles' Medium (DMEM) + fetal bovine serum (FBS); G2-SHED + DMEM + FBS + DEX; G3-SHED + DMEM + FBS + ASC + ßGLY; G4-SHED + DMEM + FBS + ASC + ßGLY + DEX; G5-MC3T3-E1 + α Minimal Essential Medium (MEM) + FBS + ASC + ßGLY. DNA content, alkaline phosphatase (ALP) activity, free calcium quantification in the extracellular medium, and extracellular matrix mineralization quantification through staining with von Kossa, alizarin red, and tetracycline were performed on days 7 and 21. Osteogenic media supplemented with ASC and ß-GLY demonstrated similar effects on SHED in the presence or absence of DEX for DNA content (day 21) and capacity to mineralize the extracellular matrix according to alizarin red and tetracycline quantifications (day 21). In addition, the presence of DEX in the osteogenic medium promoted less ALP activity (day 7) and extracellular matrix mineralization according to the von Kossa assay (day 21), and more free calcium quantification at extracellular medium (day 21). In summary, the presence of DEX in the osteogenic media supplementation did not interfere with SHED commitment into mineral matrix depositor cells. We suggest that DEX may be omitted from culture media supplementation for SHED osteogenic differentiation in vitro studies.

PLGA+HA/ßTCP Scaffold Incorporating Simvastatin: A Promising Biomaterial for Bone Tissue Engineering.

The aim of this study was to synthesize, characterize, and evaluate degradation and biocompatibility of poly(lactic-co-glycolic acid) + hydroxyapatite/ß-tricalcium phosphate (PLGA+HA/ßTCP) scaffolds incorporating simvastatin (SIM) to verify if this biomaterial might be promising for bone tissue engineering. Samples were obtained by the solvent evaporation technique. Biphasic ceramic particles (70% HA, 30% ßTCP) were added to PLGA in a ratio of 1:1. Samples with SIM received 1% (m/m) of this medication. Scaffolds were synthesized in a cylindric shape and sterilized by ethylene oxide. For degradation analysis, samples were immersed in phosphate-buffered saline at 37°C under constant stirring for 7, 14, 21, and 28 days. Nondegraded samples were taken as reference. Mass variation, scanning electron microscopy, porosity analysis, Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetry were performed to evaluate physico-chemical properties. Wettability and cytotoxicity tests were conducted to evaluate the biocompatibility. Microscopic images revealed the presence of macro-, meso-, and micropores in the polymer structure with HA/ßTCP particles homogeneously dispersed. Chemical and thermal analyses presented similar results for both PLGA+HA/ßTCP and PLGA+HA/ßTCP+SIM. The incorporation of simvastatin improved the hydrophilicity of scaffolds. Additionally, PLGA+HA/ßTCP and PLGA+HA/ßTCP+SIM scaffolds were biocompatible for osteoblasts and mesenchymal stem cells. In summary, PLGA+HA/ßTCP scaffolds incorporating simvastatin presented adequate structural, chemical, thermal, and biological properties for bone tissue engineering.

The use of zygomatic implants for the rehabilitation of atrophic maxillas with 2 different techniques: Stella and Extrasinus.

The zygomatic implant anchorage is a surgical technique that provides a new perspective for patients with severe maxillary atrophy, increasing predictability and reduced cost of treatment, besides being a tool for the hardships of the rehabilitation of such a challenging region. This article describes 2 clinical cases with zygomatic implants with different techniques (Stella and Extrasinus) and both with immediate loading and accompanying clinical radiographic follow-up procedures of 12 and 24 months, respectively.

Evaluation of the stress distribution in CFR-PEEK dental implants by the three-dimensional finite element method.

CFR-PEEK (carbon fiber reforced-poly ether ether ketone) has been demonstrated to be excellent substitute titanium in orthopedic applications and can be manufactured with many physical, mechanical, and surface properties, in several shapes. The aim of this study was to compare, using the three-dimensional finite element method, the stress distribution in the peri-implant support bone of distinct models composed of PEEK components and implants reinforced with 30% carbon fiber (30% CFR-PEEK) or titanium. In simulations with a perfect bonding between the bone and the implant, the 30% CFR-PEEK presented higher stress concentration in the implant neck and the adjacent bone, due to the decreased stiffness and higher deformation in relation to the titanium. However, 30% CFR-PEEK implants and components did not exhibit any advantages in relation to the stress distribution compared to the titanium implants and components.