Pain: Persistent postsurgery and bone cancer-related pain.

The generation of neuropathic pain is a complex dynamic process. Factors involved include one or more dysregulated sensory neural pathways; dysregulated activity of specific neurotransmitters, synapses, receptors and cognitive and emotional neural circuits; and the balance between degenerative and regenerative neural events. Risk factors include age, sex, cognition, emotions, genetic polymorphism, previous or ongoing chronic pain conditions and the use of certain drugs. Intense pain experienced before, during and after surgery is a risk factor for the development of central sensitization with consequent persistent postsurgery neuropathic pain. Blockade of N-methyl-D-aspartate receptors with appropriate drugs during and immediately after surgery may prevent persistent postsurgical pain. Most cancers, but particularly malignant metastases in bone, can induce persistent pain. Local factors including direct damage to sensory nerve fibres, infiltration of nerve roots by cancer cells and algogenic biological agents within the microenvironment of the tumour bring about central sensitization of dorsal horn neurons, characterized by neurochemical reorganization with persistent cancer pain. In this article, the clinical features, pathogenesis and principles of management of persistent postsurgery pain and cancer pain are briefly discussed.

Cellular responses evoked by different surface characteristics of intraosseous titanium implants.

The properties of biomaterials, including their surface microstructural topography and their surface chemistry or surface energy/wettability, affect cellular responses such as cell adhesion, proliferation, and migration. The nanotopography of moderately rough implant surfaces enhances the production of biological mediators in the peri-implant microenvironment with consequent recruitment of differentiating osteogenic cells to the implant surface and stimulates osteogenic maturation. Implant surfaces with moderately rough topography and with high surface energy promote osteogenesis, increase the ratio of bone-to-implant contact, and increase the bonding strength of the bone to the implant at the interface. Certain features of implant surface chemistry are also important in enhancing peri-implant bone wound healing. It is the purpose of this paper to review some of the more important features of titanium implant surfaces which have an impact on osseointegration.

Fourier transform spectral imaging microscopy (FT-SIM) and scanning Raman microscopy for the detection of indoor common contaminants on the surface of dental implants.

Endosteal dental implants are used routinely with high success rates to rehabilitate the integrity of the dentition. However if implant surfaces become contaminated by foreign material, osseointegration may not occur and the dental implant will fail because of the lack of mechanical stability. Detection and characterization of dental implant surface contaminants is a difficult task. In this article we investigate the application of several spectral microscopy methods to detect airborne contaminants on dental implant surfaces. We found that Fourier Transform Spectral Imaging Microscopy (FT-SIM) and scanning Raman microscopy provided the most useful information. Some implants possess weak and homogeneous auto-fluorescence and are best analyzed using FT-SIM methods, while others are Raman inactive and can be analyzed using scanning Raman microscopy.

Radiolucent inflammatory implant periapical lesions: a review of the literature.

PURPOSE: To discuss the terminology, etiopathogenesis, and treatment of radiolucent inflammatory implant periapical lesions. MATERIALS AND METHODS: An electronic search for relevant articles published in the English literature in the PubMed database. RESULTS: Bacterial contamination of the apical portion of the implant either from a preexisting dental periapical infection or from a periapical lesion of endodontic origin of an adjacent tooth is the probable causative factor. Aseptic bone necrosis owing to overheating of the bone during preparation of osteotomies, or compression of the bone at the apex of the implant owing to excessive tightening, may also play a role. The histopathological features are of a mixed inflammatory cell infiltrate on a background of granulation tissue consistent with either a granuloma or an abscess as may be found at the apex of a nonvital tooth. Treatment consists of immediate and aggressive surgical debridement, chemical detoxification of the apical portion of the exposed implant surface, and systemic antibiotics with or without a bone regenerative procedure. CONCLUSION: A radiolucent inflammatory implant periapical lesion is analogous to either a granuloma or an abscess as may be found at the apex of a nonvital tooth.

Melanin: the biophysiology of oral melanocytes and physiological oral pigmentation.

The presence of melanocytes in the oral epithelium is a well-established fact, but their physiological functions are not well defined. Melanin provides protection from environmental stressors such as ultraviolet radiation and reactive oxygen species; and melanocytes function as stress-sensors having the capacity both to react to and to produce a variety of microenvironmental cytokines and growth factors, modulating immune, inflammatory and antibacterial responses. Melanocytes also act as neuroendocrine cells producing local neurotransmitters including acetylcholine, catecholamines and opioids, and hormones of the melanocortin system such as proopiomelanocortin, adrenocorticotropic hormone and α-melanocyte stimulating hormone, that participate in intracellular and in intercellular signalling pathways, thus contributing to tissue homeostasis.There is a wide range of normal variation in melanin pigmentation of the oral mucosa. In general, darker skinned persons more frequently have oral melanin pigmentation than light-skinned persons. Variations in oral physiological pigmentation are genetically determined unless associated with some underlying disease.In this article, we discuss some aspects of the biophysiology of oral melanocytes, of the functions of melanin, and of physiological oral pigmentation.

Human immunodeficiency virus (HIV)-associated extranodal T cell non-Hodgkin lymphoma of the oral cavity.

T cell non-Hodgkin lymphoma is characterized by uncontrolled cellular proliferation of immature malignant clones. HIV-associated T cell non-Hodgkin lymphoma comprises a heterogeneous group of lymphoproliferative neoplastic entities classified according to morphological, immunological, genetic and clinical features. Extranodal T cell non-Hodgkin lymphoma of the oral cavity is uncommon. A case is presented with extranodal T cell non-Hodgkin lymphoma as an initial sign of HIV-infection. The characteristics of HIV-associated non-Hodgkin lymphoma are discussed.

HIV-associated oral Kaposi sarcoma and HHV-8: a review.

Kaposi sarcoma is the most common malignant tumour associated with HIV infection. In the majority of cases oral tissues are involved and in 22% the initial presentation is in the oral cavity. The oral lesions are either single or multifocal, and the palate, gingiva and tongue are the sites most frequently involved. The pathogenesis of Kaposi sarcoma in HIV-seropositive subjects is complex. It involves interaction between human herpesvirus-8 (HHV-8) and HIV, altered cellular signal transduction pathways, and increased production of cytokines and growth factors. The multifactorial nature and clinical stages in the growth of oral Kaposi sarcoma are discussed.

Enamel dysplasia with odontogenic fibroma-like hamartomas: review of the literature and report of a case.

This article reports on a case presenting with a rare syndrome characterized by enamel dysplasia and multiple unerupted teeth with large solid fibrous pericoronal lesions manifesting with odontogenic fibroma-like features. Our case shows in addition to these findings an anterior open bite malocclusion and gingival overgrowths. These overgrowths exhibit the microscopic features of the multiple pericoronal odontogenic fibroma-like lesions that appear to be the hallmark of this syndrome. This unusual case brings the total number documented in the literature to 5, all of which were reported from South Africa.