Francisco Javier Rodríguez-Lozano

Mesenchymal stem cells derived from dental tissues

Regeneration of tissues occurs naturally due to the existence of stem cells with the capacity to self-regenerate and differentiate; however, regenerative capacity decreases with age, and in many cases, regeneration is not sufficient to repair the damage produced by degenerative, ischaemic, inflammatory, or tumour-based diseases. In the last decade, advances have been made in the understanding of stem cells, the genes that control the alternative fates of quiescence and differentiation, and the niches that provide specific signals that modulate cell fate decisions. Embryonic stem-cell research is shedding light on the secrets of development. Adult stem cells (AS cells) are available from several sources. Bone marrow and connective tissue have been used in preliminary clinical trials for regenerative therapy. Recently, several types of AS cells have been isolated from teeth, including dental pulp stem cells, stem cells from human exfoliated deciduous teeth, periodontal ligament stem cells, dental follicle progenitor stem cells and stem cells from apical papilla. Preliminary data suggest that these cells have the capacity to differentiate into osteoblasts, adipocytes, chondrocytes and neural cells. If confirmed, these data would support the use of these cells, which are easily obtained from extracted teeth, in dental therapies, including in regenerative endodontics, providing a new therapeutic modality.

Neuropathic orofacial pain after dental implant placement: review of the literature and case report.

Persistent and chronic pain is more common in the head and neck region than in any other part of the body; therefore, dentists are more likely to encounter these rather complex cases in their practices. In this report, we present a brief review of neuropathic orofacial pain (NOP) that can begin after deafferentation of trigeminal nerve fibers after root canal treatment, apicoectomy, tooth extraction, or implant placement or idiopathically. A case of NOP occurring after a surgical implant procedure in a 62-year-old woman is presented. Continuous pain started 6 months after the placement of 8 dental implants in the maxilla, at the time of positioning the prosthesis on her implants. After being subjected to a physical examination and relevant complementary radiologic imaging, the patient was diagnosed with an NOP secondary to nerve impingement due to dental implant placement as well as myofascial head and neck pain.

Human adult periodontal ligament-derived cells integrate and differentiate after implantation into the adult mammalian brain.

Previous studies suggest that neural crest (NC)-derived stem cells may reside in NC derivatives including the human periodontal ligament (hPDL). The isolation and manipulation of autologous NC-derived cells could be an accessible source of adult neural stem cells for their use in cell replacement and gene transfer to the diseased central nervous system. In this study, we examined the expression of NC markers and neural differentiation potential of hPDL-derived cells both in vitro and in vivo. In vitro we found that hPDL-derived cells expressed stem cell markers (Oct3/4, Nestin, Sox2, and Musashi-1) and a subset of NC cell markers (Slug, p75NTR, Twist, and Sox9). hPDL-derived cells differentiated into neural-like cells based on cellular morphology and neural marker expression (TUJ1, MAP2, MAP1b, GAD65/67, GABA, NeuN, ChAT, GAT1, synaptophysin, GFAP, NG2, and O4). In vivo, hPDL-derived cells survive, migrate, and give rise to DCX+, NF-M+, GABA+, GFAP+, and NG2+ cells after grafting the adult mouse brain. Some of the grafted hPDL-derived cells were located in stem cell niches such as the ventricular epithelium and the subventricular zone of the anterolateral ventricle wall as well as in the subgranular zone of the hippocampal dentate gyrus. Thus, the hPDL contains stem cells that originate from the NC and can differentiate into neural cells. The engraftment and differentiation properties of hPDL-derived cells in the adult brain indicate that they are a potential stem cell source to be used in neuroregenerative and/or neurotrophic medicine.

Prevalence of temporomandibular disorder–related findings in violinists compared with control subjects

OBJECTIVE The aim of this study was to determine if there is an association between violin playing and the presence of signs and symptoms of temporomandibular disorder (TMD). STUDY DESIGN We studied a group of violinists in the Murcia region of Spain, who were examined for TMD. The results were compared with those from a random control group who did not play any musical instrument. The groups were matched by age and gender. Statistical analysis was carried out using SPSS 15.0 statistical software. RESULTS Compared with the control subjects, the violinists as a group had significantly more pain in maximum mouth opening (P < .005), parafunctional habits (P = .001), and occurrence of temporomandibular joint sounds (P < .005) as determined by chi-squared. CONCLUSIONS Violin playing appears to be a factor associated with TMD-related findings.

Cell therapy in bisphosphonate-related osteonecrosis of the jaw.

ObjectiveBisphosphonate-related osteonecrosis of the jaw (BRONJ) is a clinical condition found in patients who have received intravenous or oral bisphosphonate therapy for various diseases related to bone. This report describes a novel treatment of BRONJ using autologous bone marrow stem cells, platelet-rich plasma, beta tricalcium phosphate, and demineralized bone matrix. Study DesignWe report a 71-year-old woman with history of multiple myeloma treated with intravenous zoledronic acid during 4 years. After a tooth extraction, the patient presented with a painful BRONJ lesion with no healing wound and cortical bone exposure. The patient was surgically managed with a standardized protocol of autologous stem cell therapy combining bone marrow harvest, cell concentration procedures, and intraoral surgery. ResultsCT scan performed 6 months later showed improvement of bone and concentric ossification. Cellular therapy might be considered a new strategy to heal BRONJ lesions.

Joint hypermobility and disk displacement confirmed by magnetic resonance imaging: A study of women with temporomandibular disorders

OBJECTIVE The objective of this study was to test whether or not there is an association between generalized joint hypermobility (measured using the Beighton score) and temporomandibular joint disk displacement in women who had sought medical attention for temporomandibular disorders (TMD). STUDY DESIGN We studied 66 women who were attending the clinic for TMD. The patients were examined for joint hypermobility, and Beighton scores were calculated. When it was suspected that a patient suffered arthropathic complaints, magnetic resonance imaging of both temporomandibular joints was performed with the mouth closed and at maximal opening. The Pearson chi-squared test was used to test for an association between generalized joint hypermobility and disk displacement. RESULTS We were unable to confirm the existence of an association between generalized joint hypermobility and temporomandibular joint disk displacement in women (chi(2) = 1.523; P = .02). CONCLUSION Generalized joint hypermobility may be a factor related to TMD, but we did not find an association between generalized joint hypermobility and anterior disk displacement in women.

Graphene for the development of the next-generation of biocomposites for dental and medical applications

OBJECTIVE Graphene and its derivatives, graphene oxide (GO) and reduced graphene oxide (rGO), are 2D carbon-based materials with remarkable physical, chemical and biological properties. Graphene sheets have high specific surface area and mechanical strength. Moreover, they have been shown to influence the differentiation of stem cells and to improve properties of biomaterials. METHODS Here, we present the recent achievements on the use of graphene and its derivatives to improve properties and enhance bioactivity of biomaterials. We also discuss the biosafety constraints to be solved to translate these carbonaceous materials to the clinic. RESULTS Graphene and its derivatives can be functionalized and further modified with several bioactive molecules. They can be combined with several biomaterials used in regenerative and reconstructive dentistry and medicine. The resultant graphene-modified composites often present improved physico-mechanical properties and enhanced bioactivity. Moreover, graphene-modified composites are promising candidates to deliver growth factors, drugs and others bioactive compounds. SIGNIFICANCE Graphene can improve the physical, chemical and mechanical properties of biomaterials. As it can be functionalized and combined with several biomolecules, graphene holds enormous potential to be used as drug carriers or substrates and scaffolds for cell-based tissue engineering strategies.

Cytotoxicity of GuttaFlow Bioseal, GuttaFlow2, MTA Fillapex, and AH Plus on Human Periodontal Ligament Stem Cells

Introduction: The aim of the present study was to evaluate the in vitro cytotoxicity of endodontic sealers (GuttaFlow Bioseal, GuttaFlow2, and MTA Fillapex) on human periodontal ligament stem cells (hPDLSCs). As a reference, AH Plus was compared with the more recent endodontic sealers regarding cell viability and cell attachment. Methods: Biological testing was carried out in vitro on hPDLSCs. Cell viability assay was performed by using eluates from each endodontic sealer. To assess cell morphology and attachment to the different sealers, the hPDLSCs were directly seeded onto the material surfaces and analyzed by scanning electron microscopy. Chemical composition of the sealers was determined by energy‐dispersive x‐ray, and eluates were analyzed by inductively coupled plasma mass spectrometry. Statistical differences were assessed by analysis of variance and Tukey test (P < .05). Results: Cell viability was evident after 24 hours in the presence of GuttaFlow Bioseal and GuttaFlow 2 but not in the case of AH Plus or MTA Fillapex. At 168 hours, GuttaFlow Bioseal and GuttaFlow 2 exhibited high and moderate cell viability, respectively, whereas AH Plus and MTA Fillapex revealed low rates of cell cell viability (P < .001). Finally, scanning electron microscopy studies revealed a high degree of proliferation, cell spreading, and attachment, especially when using GuttaFlow Bioseal disks. Conclusions: GuttaFlow Bioseal and GuttaFlow2 showed lower cytotoxicity than MTA Fillapex and AH plus. Further in vitro and in vivo investigations are required to confirm the suitability of GuttaFlow Bioseal for clinical application. HIGHLIGHTSThe sealerss extracts caused dose‐ and time‐dependent effects on hPDLSCs.GuttaFlow Bioseal exhibited better cytocompatibility than the other sealers.Further in vitro and in vivo investigations of GuttaFlow Bioseal are required.

Biocompatibility of New Pulp-capping Materials NeoMTA Plus, MTA Repair HP, and Biodentine on Human Dental Pulp Stem Cells

Introduction: The aim of the present study was to evaluate the in vitro cytotoxicity of MTA Repair HP, NeoMTA Plus, and Biodentine, new bioactive materials used for dental pulp capping, on human dental pulp stem cells (hDPSCs). Methods: Biological testing was carried out in vitro on hDPSCs. Cell viability and cell migration assays were performed using eluates of each capping material. To evaluate cell morphology and cell attachment to the different materials, hDPSCs were directly seeded onto the material surfaces and analyzed by scanning electron microscopy. The chemical composition of the pulp‐capping materials was determined by energy‐dispersive X‐ray and eluates were analyzed by inductively coupled plasma‐mass spectrometry. Statistical differences were assessed by analysis of variance and Tukey test (P < .05). Results: Cell viability was moderate after 24 and 48 hours in the presence of MTA Repair HP and NeoMTA Plus, whereas at 48 and 72 hours, Biodentine showed higher rates of cell viability than MTA Repair HP and NeoMTA Plus (P < .001). A cell migration assay revealed adequate cell migration rates for MTA Repair HP and NeoMTA Plus, both similar to the control group rates, meanwhile the highest cell migration rate was observed in the presence of Biodentine (P < .001). Scanning electron microscope studies showed a high degree of cell proliferation and adhesion on Biodentine disks but moderate rates on MTA Repair HP and NeoMTA Plus disks. Energy‐dispersive X‐ray pointed to similar weight percentages of C, O, and Ca in all 3 materials, whereas other elements such as Al, Si, and S were also found. Conclusions: The new pulp‐capping materials MTA Repair HP, NeoMTA Plus, and Biodentine showed a suitable degree of cytocompatibility with hDPSCs, and good cell migration rates, although Biodentine showed higher rates of proliferation time‐dependent. HighlightsResults of this work suggest that hDPSCs show suitable biological response in terms of cell viability, cell proliferation, and cell migration when in contact with extracts from NeoMTA Plus, MTA Repair HP, and Biodentine.NeoMTA Plus and MTA Repair HP exhibited similar cytocompatibility and cell attachment with hDPSCs, whereas Biodentine promotes higher proliferation rates, cell migration, and cell attachment.Further in vitro and in vivo investigations are required to contrast these results and to prove suitable clinical applications of NeoMTA Plus and MTA Repair HP.

Potential of graphene for tissue engineering applications.

Q2 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 To Editor, We read with great interest the article published by Empson et al. The authors suggested the use of nanocarbon particles as graphene to replace damaged connective tissues. In fact, nanocarbons including carbon nanotubes, carbon nanohorns, and graphenes have also shown an enhancement of matrix mechanical properties; their small size and functional capabilities make them attractive therapeutic options as nanofillers for many regenerative medicine applications. In our recent study, we evaluated the effects of the novel biomaterials graphene oxide (GO) and silk fibroin composites on human periodontal ligament mesenchymal stem cells (PDLSCs) phenotype, adhesion, proliferation rate, and viability. Biocompatibility of scaffolds is a prerequisite for generating cell-biomaterial constructs and for their successful clinical application. GO and fibroin-based biomaterials have been previously studied for several tissue engineering based-therapies, but they have never been tested in conjunction with PDLSCs. Morphologic studies by staining of actin cytoskeleton of PDLSCs cultured for different times on GO and fibroin-coated surfaces showed that PDLSCs cultured on fibroin films displayed lower F-actin polymerization, lower cell spreading, and delayed initial adhesion to the biomaterial. By contrast, GO or GO plus fibroin-coated surfaces significantly improved F-actin polymerization, cell spreading, and initial adhesion when compared with fibroin alone. Furthermore, the proliferation rate and phenotype of PDLSCs on GO and fibroin-based biomaterials by MTT colorimetric assays and flow cytometry, respectively, were studied.