Peripheral Purinergic Modulation in Pediatric Orofacial Inflammatory Pain Affects Brainstem Nitroxidergic System: A Translational Research.

Physiology of orofacial pain pathways embraces primary afferent neurons, pathologic changes in the trigeminal ganglion, brainstem nociceptive neurons, and higher brain function regulating orofacial nociception. The goal of this study was to investigate the nitroxidergic system alteration at brainstem level (spinal trigeminal nucleus), and the role of peripheral P2 purinergic receptors in an experimental mouse model of pediatric inflammatory orofacial pain, to increase knowledge and supply information concerning orofacial pain in children and adolescents, like pediatric dentists and pathologists, as well as oro-maxillo-facial surgeons, may be asked to participate in the treatment of these patients. The experimental animals were treated subcutaneously in the perioral region with pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS), a P2 receptor antagonist, 30 minutes before formalin injection. The pain-related behavior and the nitroxidergic system alterations in the spinal trigeminal nucleus using immunohistochemistry and western blotting analysis have been evaluated. The local administration of PPADS decreased the face-rubbing activity and the expression of both neuronal and inducible nitric oxide (NO) synthase isoforms in the spinal trigeminal nucleus. These results underline a relationship between orofacial inflammatory pain and nitroxidergic system in the spinal trigeminal nucleus and suggest a role of peripheral P2 receptors in trigeminal pain transmission influencing NO production at central level. In this way, orofacial pain physiology should be elucidated and applied to clinical practice in the future.

Periodontitis Stage III-IV, Grade C and Correlated Factors: A Histomorphometric Study.

BACKGROUND: Periodontitis is a disease that leads to serious functional and esthetic dysfunctions. Periodontitis exists in different forms, and its etiology is related to multiple component causes. Two key processes involved in the evolution of this pathology are angiogenesis and inflammatory infiltrate. The aim of this study was to understand if important factors such as smoking, gender, age, plaque, pus, and probing pocket depth could influence the histomorphological pattern of generalized stage III-IV, grade C periodontitis (GPIII-IVC), which is a particular form of periodontitis. METHODS: Eighteen subjects with GPIII-IVC were enrolled in this study. The percentage of inflammatory cells and the vascular area were measured and evaluated in relation to each periodontal disease-associated factor. RESULTS: Females showed a significant increase in the percentage of inflammatory cells compared to males (6.29% vs. 2.28%, p-value = 0.020) and it was higher in non-smokers than in smokers (4.56% vs. 3.14%, p-value = 0.048). Young patients showed a significant increase in vascular area percentage compared to older patients (0.60% vs. 0.46%, p-value = 0.0006) and this percentage was also higher in non-smokers compared to smokers (0.41% vs. 0.55%, p-value = 0.0008). The vascular area was also more than halved in subjects with residual plaque on tooth surfaces (0.74% vs. 0.36%, p-value = 0.0005). CONCLUSIONS: These results suggested that even if these factors are commonly related to the worsening of periodontal status, some of them (pus and periodontal probing depth (PPD)) do not affect the inflammatory and vascular patterns.

Beneficial Effects of Concentrated Growth Factors and Resveratrol on Human Osteoblasts In Vitro Treated with Bisphosphonates.

Bisphosphonates are primary pharmacological agents against osteoclast-mediated bone loss and widely used in the clinical practice for prevention and treatment of a variety of skeletal conditions, such as low bone density and osteogenesis imperfecta, and pathologies, such as osteoporosis, malignancies metastatic to bone, Paget disease of bone, multiple myeloma, and hypercalcemia of malignancy. However, long-term bisphosphonate treatment is associated with pathologic conditions including osteonecrosis of the jaw, named BRONJ, which impaired bone regeneration process. Clinical management of BRONJ is controversy and one recent approach is the use of platelet concentrates, such as Concentrated Growth Factors, alone or together with biomaterials or antioxidants molecules, such as resveratrol. The aim of the present study was to investigate the in vitro effects of Concentrated Growth Factors and/or resveratrol on the proliferation and differentiation of human osteoblasts, treated or not with bisphosphonates. Human osteoblasts were stimulated for 3 days in complete medium and for 21 days in mineralization medium. At the end of the experimental period, the in vitro effect on osteoblast proliferation and differentiation was evaluated using different techniques such as MTT, ELISA for the quantification/detection of osteoprotegerin and bone morphogenetic protein-2, immunohistochemistry for sirtuin 1 and collagen type I, and the Alizarin Red S staining for the rate of mineralization. Results obtained showed that Concentrated Growth Factors and/or resveratrol significantly increased osteoblast proliferation and differentiation and that the cotreatment with Concentrated Growth Factors and resveratrol had a protective role on osteoblasts treated with bisphosphonates. In conclusion, these data suggest that this approach could be promised in the clinical management of BRONJ.

Altered immunolocalization of heat-shock proteins in human peri-implant gingiva.

It has been suggested that heat-shock proteins (HSPs) might be involved in autoimmune disease mechanisms in humans, considering the high degree of sequence homology between bacterial and human HSPs. Several authors have postulated that HSPs might be involved in periodontal disease processes, but not specifically in peri-implantitis. Consequently, using immunohistochemical techniques, we studied the distribution of HSP25, HSP32, HSP60 and HSP72 in three groups of patients: (1) subjects with natural teeth (healthy periodontal tissue), (2) subjects with normal peri-implant mucosa and (3) subjects with clinically evident peri-implantitis. The immunolabelling for HSP25 and HSP60 was increased in the peri-implantitis group HSP32 immunolabelling slightly decreased in peri-implant and peri-implantitis gingiva. Labelling for HSP72 was undetectable in all three groups. In conclusion, we observed in peri-implantitis a clearly enhanced immunolabelling of two specific HSPs, HSP25 and HSP60, restricted to gingival epithelium and this could indicate a signal of local altered homeostasis.

Sodium-DNA for Bone Tissue Regeneration: An Experimental Study in Rat Calvaria.

Surgical techniques in dental and maxillofacial surgery request fast bone tissue regeneration, so there is a significant need to improve therapy for bone regeneration. Several studies have recently underlined the importance of nucleotides and nucleosides to increase cell proliferation and activity; in particular, the ability of polydeoxyribonucleotide (PDRN) to induce growth and activity of human osteoblasts was demonstrated. Sodium-DNA is the deoxyribonucleic acid (DNA) extracted from the gonadic tissue of male sturgeon and then purified, depolymerized, and neutralized with sodium hydroxide. To date, there are no evidences about the use of Sodium-DNA for bone tissue regeneration. Consequently, our question is about the efficacy of Sodium-DNA in bone healing. For testing the role of Sodium-DNA in bone healing we used a rat calvarial defect model. Sodium-DNA at different concentrations used alone or in association with Fibrin and/or Bio-Oss was used for healing treatments and the bone healing process was evaluated by histomorphometric and immunohistochemical analyses. Our results suggested a positive effect of Sodium-DNA in bone regeneration, providing a useful protocol and a model for the future clinical evaluation of its osteogenic properties.

Histochemical and immunohistochemical evaluation of gingival collagen and metalloproteinases in peri-implantitis.

The extra-cellular matrix of the gingival tissue plays an important role in the homeostasis of dental implants. In this work we have studied immunohistochemically the distribution of collagen I-III-IV-V, tenascin, metalloproteinases (MMP) 1-3-8-13 and TIMP-1 in three groups of patients: (1) subjects with natural teeth (healthy periodontal tissue), (2) subjects with normal peri-implant mucosa and (3) subjects with clinically evident peri-implantitis. The immunolabelling for collagen I-III-IV showed a similar pattern in all three groups. The labelling for collagen V increased in lamina propria of healthy peri-implant tissue and peri-implantitis. Tenascin immunolabelling in healthy and peri-implant tissues was scattered in lamina propria. In peri-implantitis tenascin immunolabelling increased mainly near to the basal lamina. The MMP-1-3-8 and TIMP-1 immunolabelling were very faint and localized in the stroma in all three groups. In healthy and peri-implant tissues MMP-13 immunolabelling was found in the lamina propria whereas in peri-implantitis MMP-13 immunolabelling was also in epithelium. On the whole, these data suggest that in the extracellular matrix of peri-implantitis there are alterations of collagen V, tenascin and MMP-13 patterns.

Epithelial expression of vanilloid and cannabinoid receptors: a potential role in burning mouth syndrome pathogenesis.

Burning mouth syndrome (BMS) is an intra-oral burning sensation for which presently no medical or dental causes have been found, and in which the oral mucosa appears normal. It remains an unknown disease for which there is still no long-term treatment. The aim of this study was to assess the epithelial alteration of transient receptor potential vanilloid channel type 1 (TRPV1) and cannabinoid receptors type 1 (CB1) and type 2 (CB2) in the human tongue. The study was performed on eight healthy controls and eight BMS patients. All patients underwent a 3-mm punch biopsy at the anterolateral aspect of the tongue close to the tip. TRPV1, CB1 and CB2 immuno-histochemistry was carried out showing an altered expression of all receptors. In BMS patients there was increased TRPV1, decreased CB1 and increased CB2 expression in tongue epithelial cells also associated with a change in their distribution. It would appear that these receptors are related to BMS. These data could be useful for future characterization of BMS epithelial markers and therapy.