RESUMEN
Previous studies have shown that peripheral ionotropic glutamate receptors are involved in the increase in sensitivity of a cutaneous branch of spinal dorsal ramus (CBDR) through antidromic electrical stimulation (ADES) of another CBDR in the adjacent segment. CBDR in the thoracic segments run parallel to each other and no synaptic contact at the periphery is reported. The present study investigated whether the increased sensitivity of peripheral sensory nerves via ADES of a CBDR induced Fos expression changes in the adjacent segments of the spinal cord. Fos expression increased in the T8 - T12 segments of the spinal cord evoked by ADES of the T10 CBDR in rats. The increased Fos expression in the T11 and T12, but not T8 - T10 spinal cord segments, was significantly blocked by local application of either N-methyl-D-aspartate (NMDA) receptor antagonist dizocilpine maleate (MK-801) or non-NMDA receptor antagonist 6,7-dinitroquinoxaline-2,3-dione (DNQX) into the receptive field of T11 CBDR. The results suggest that endogenous glutamate released by ADES of sensory nerve may bind to peripheral ionotropic glutamate receptors and activate adjacent sensory nerve endings to increase the sensitivity of the spinal cord. These data reveal the potential mechanisms of neuron activation in the spinal cord evoked by peripheral sensitization.
Asunto(s)
Ganglios Espinales/metabolismo , Proteínas Proto-Oncogénicas c-fos/metabolismo , Receptores Ionotrópicos de Glutamato/metabolismo , Médula Espinal/metabolismo , Vías Aferentes/metabolismo , Animales , Estimulación Eléctrica , Masculino , Ratas Sprague-Dawley , Piel/inervaciónRESUMEN
OBJECTIVE: To investigate the long-term clinical outcomes of porcelain laminate veneers 1-8 years following delivery. METHODS: A total of 310 feldspathic porcelain laminate veneers on anterior teeth or premolars in 49 patients were included in the present study 1-8 years following delivery. All the subjects underwent a detailed clinical examination utilizing modified United States Public Health Service (USPHS) criteria. Restoration integrity, abrasion, color satisfaction, marginal discoloration, marginal adaptation, secondary caries, postoperative sensitivity, and gingival index (GI) of the prostheses were evaluated according to modified USPHS criteria. The 1-8 year survival rates of the veneers were statistically analyzed using the life table method. RESULTS: The survival rates of porcelain laminate veneers were 98.7%, 98.0%, 93.8%, 93.2%, 89.7%, 81.8%, 76.3%, and 76.3% in 1 to 8 years, respectively. CONCLUSIONS: The long-term clinical outcomes of porcelain laminate veneers are satisfying.