The dental pulp in human primary teeth is densely innervated by a plethora of nerve endings at the coronal pulp-dentin interface. This study analyzed how the physiological root resorption (PRR) process affects dental pulp innervation before exfoliation of primary teeth. Forty-four primary canine teeth, classified into 3 defined PRR stages (early, middle, and advanced) were fixed and demineralized. Longitudinal cryosections of each tooth were stained for immunohistochemical and quantitative analysis of dental pulp nerve fibers and associated components with confocal and electron microscopy. During PRR, axonal degeneration was prominent and progressive in a Wallerian-like scheme, comprising nerve fiber bundles and nerve endings within the coronal and root pulp. Neurofilament fragmentation increased significantly during PRR progression and was accompanied by myelin degradation and a progressive loss of myelinated axons. Myelin sheath degradation involved activation of autophagic activity by Schwann cells to remove myelin debris. These cells expressed a sequence of responses comprising dedifferentiation, proliferative activity, GAP-43 overexpression, and Büngner band formation. During the advanced PRR stage, increased immune cell recruitment within the dental pulp and major histocompatibility complex (MHC) class II upregulation by Schwann cells characterized an inflammatory condition associated with the denervation process in preexfoliative primary teeth. The ensuing loss of dental pulp axons is likely to be responsible for the progressive reduction of sensory function of the dental pulp during preexfoliative stages.

Schwann cells are glial cells that support axonal development, maintenance, defense, and regeneration in the peripheral nervous system. There is limited knowledge regarding the organization, plasticity, and aging of Schwann cells within the dental pulp in adult permanent teeth. The present study sought to relate changes in the pattern of Schwann cell phenotypes between young and old adult teeth with neuronal, immune, and vascular components of the dental pulp. Schwann cells are shown to form a prominent glial network at the dentin-pulp interface, consisting of nonmyelinating and myelinating phenotypes, forming a multicellular neuroimmune interface in association with nerve fibers and dendritic cells. Schwann cell phenotypes are recognized by the expression of S100, glial fibrillary acidic protein (GFAP), myelin basic protein (MBP), Sox10, GAP43, and p75NTR markers. In young adult teeth, a dense population of nonmyelinating Schwann cells projects processes in close association with sensory nerve terminals through the odontoblast layer, reaching the adjacent predentin/dentin domain. While GAP43 and p75NTR are highly expressed in nonmyelinating Schwann cells from young adult teeth, the presence of these markers declines significantly in old adult teeth. Myelinated axons, identified by MBP expression, are mainly present at the Raschkow plexus and within nerve bundles in the dental pulp, but their density is significantly reduced in old adult versus young adult teeth. These data reveal age-related changes within the glial network of the dental pulp, in association with a reduction of coronal dental pulp innervation in old adult versus young adult teeth. The prominence of Schwann cells as a cellular component at the dentin-pulp interface supports the notion that their association with sensory nerve terminals and immune system components forms part of an integrated multicellular barrier for defense against pathogens and dentin repair.

El síndrome de la boca ardiente (SBA) es una entidad nosológica, más frecuente en mujeres menopáusicas. Su principal característica es una sintomatología urente y/o dolorosa de la mucosa bucal (principalmente en la lengua), sin hallazgos clínicos aparentes que expliquen la aparición de esta sensación. Se encuentra relacionado con una serie de factores locales y sistémicos posibles desencadenantes, por lo que se considera de etiología multifactorial. El tratamiento va dirigido a mejorar la sintomatología y controlar los factores. Las terapias propuestas consistentes en control de factores locales, factores sistémicos y psicológicos y algunas indicaciones farmacoló-gicas, proporcionan resultados mediocres. En términos generales, el SBA continúa siendo objeto de estudios en el ámbito de la medicina bucal en busca de un diagnóstico más preciso y de una terapéutica más eficaz.Palabras clave: Síndrome de boca ardiente, Glosodinia, Menopausia. ABSTRACTBurning mouth syndrome (BMS)is a nosological entity, frequent in women in the menopausal period, which principal characteristic is a burning andlor pain sensation of the oral cavity (principally in the tongue). However, the oral mucosa often appears normal, with no apparent organic cause to account for the symptomatology. This syndrome is found to be related which a series of local and systemic factors as possible cause. Therefore is to be considerate a pathology with multifactorial etiology. The treatment is directed to improve the symptomatology and to control the factors. The proposal therapies, related to the control of local, systemic and psychological factors and some pharmacological indications, provide poor results. In general terms the BMS is still the object of many studies in the environment of the oral medicine, in order to search several aspects of diagnose and a more effective therapy.Key words: Burning mouth syndrome, glossodynia, menopause. INTRODUCCIÓNEl síndrome de la boca ardiente (SBA) es un cuadro clínico muy frecuente, caracterizado por una sensación espontánea anormal descrita por el paciente como quemazón, ardor, escozor, que afecta la mucosa bucal, generalmente en ausencia de datos clínicos y de laboratorio que justifiquen estos síntomas (1-7). La zona de mayor afectación es la lengua (punta y bordes), por lo que se le ha llamado "glosodinia" y "glosopirosis" (lengua ardiente) (7-9). Comúnmente, además de ardor, los pacientes experimentan sínto-mas tales como alteración del gusto, sensación punzante, sequedad, intolerancia a las prótesis (7). Estas condiciones se presentan como parte del SBA o bien de forma alternativa (2). Es más frecuente en mujeres en edades medias-altas de la vida. Concretamente es típico en mujeres perimenopáusicas (10).La falta de signos clínicos aumenta su complejidad y hace difícil su diagnóstico, al cual se le ha prestado atención esporádica en la bibliografía, durante los AVANCES EN ODONTOESTOMATOLOGÍAII93