Osteogenic differentiation of mesenchymal stem cells from dental bud: Role of integrins and cadherins.

Several studies have reported the beneficial effects of mesenchymal stem cells (MSCs) in tissue repair and regeneration. New sources of stem cells in adult organisms are continuously emerging; dental tissues have been identified as a source of postnatal MSCs. Dental bud is the immature precursor of the tooth, is easy to access and we show in this study that it can yield a high number of cells with ≥95% expression of mesenchymal stemness makers and osteogenic capacity. Thus, these cells can be defined as Dental Bud Stem Cells (DBSCs) representing a promising source for bone regeneration of stomatognathic as well as other systems. Cell interactions with the extracellular matrix (ECM) and neighboring cells are critical for tissue morphogenesis and architecture; such interactions are mediated by integrins and cadherins respectively. We characterized DBSCs for the expression of these adhesion receptors and examined their pattern during osteogenic differentiation. Our data indicate that N-cadherin and cadherin-11 were expressed in undifferentiated DBSCs and their expression underwent changes during the osteogenic process (decreasing and increasing respectively), while expression of E-cadherin and P-cadherin was very low in DBSCs and did not change during the differentiation steps. Such expression pattern reflected the mesenchymal origin of DBSCs and confirmed their osteoblast-like features. On the other hand, osteogenic stimulation induced the upregulation of single subunits, αV, ß3, α5, and the formation of integrin receptors α5ß1 and αVß3. DBSCs differentiation toward osteoblastic lineage was enhanced when cells were grown on fibronectin (FN), vitronectin (VTN), and osteopontin (OPN), ECM glycoproteins which contain an integrin-binding sequence, the RGD motif. In addition we established that integrin αVß3 plays a crucial role during the commitment of MSCs to osteoblast lineage, whereas integrin α5ß1 seems to be dispensable. These data suggest that functionalization of biomaterials with such ECM proteins would improve bone reconstruction therapies starting from dental stem cells.

Fixation of atrophic edentulous mandible fractures by bone plating at the inferior border.

PURPOSE: No consensus has been reached regarding the best treatment for repair of fractures of the severely atrophic mandible (<10 mm vertical height). The most complete Cochrane review of the published data could not substantiate a single best practice recommendation for treating these fractures. The present study reports the results of such treatment by placing miniplates at the inferior border of the mandible of 23 fractures of the mandibular body in 16 patients. MATERIALS AND METHODS: This was a consecutive case series during a 30-year period performed by a single surgeon at several practice locations using the technique of extraoral plating at the inferior border. All patients were prospectively monitored clinically and radiographically for achievement of bony union and for complications of sensory disturbances of the lower lip, delayed healing, and hardware removal. The mean observation time was 23.1 months (range 1 to 60), with only 2 cases observed for less than 6 months. RESULTS: All the patients achieved clinical union of their fractures. Two cases of fibrous union did not reach ossification until 5 months after surgery. The hardware removal rate was 13.6%, and the infection/prolonged inflammation rate was 13.6%. There was 1 case of malunion. Those patients who had dentures were able to return to denture wearing postoperatively. CONCLUSIONS: Miniplate fixation of fractures of the severely atrophic mandible at the inferior border is safe and effective.

The ImmunoCAP ISAC molecular allergology approach in adult multi-sensitized Italian patients with respiratory symptoms.

OBJECTIVES: To evaluate the performances of an allergen microarray in multi-sensitized allergic patients with respiratory symptoms. DESIGN AND METHODS: 321 patients and 92 controls were included in this study. Specific serum IgE were assayed using ImmunoCAP ISAC, a microarray containing 103 components derived from 47 allergens and results were compared with extract-based ImmunoCAP Allergens sIgE to 15 common airborne allergens. RESULTS: The reproducibility of ISAC was good. The Positive Percent Agreement (PPA) varied between 75% and 100% for sIgE levels above 1 kUA/l. For samples with sIgE levels below 0.1 kUA/l, the Negative Percent Agreement (NPA) ranged between 90% and 100%. Notably, 58% of respiratory allergy patients had IgE to food-specific proteins and 52% resulted sensitized to cross-reactive pan-allergens. CONCLUSION: ImmunoCAP ISAC detects allergen sensitization at component level and adds important information by defining both cross and co-sensitization to a large variety of allergen molecules.

Maxillary bone growth and implant positioning in a young patient: a case report.

The literature supports the efficacy of osseointegrated implants for partially edentulous patients, but care must be exercised in adolescents with incomplete bone formation. Implants do not follow the normal growth of the jaws, and they behave like ankylosed teeth. They may also interfere with the normal growth of the alveolar process and jeopardize the germs of the adjacent permanent teeth or alter eruption. This case report analyzes the unfavorable clinical and radiographic findings of a single-tooth replacement in a young male over a 15-year period.