RESUMEN
OBJECTIVE: Dentine hypersensitivity may occur due to loss of covering enamel and/or loss of cementum after gingival recession, resulting in exposure of cervical dentine and patency of dentinal tubules. The effect of thermally cooled pulsed neodymium:yttrium-aluminium-garnet (Nd:YAG) laser on the permeability and structural appearance of the root canal wall was investigated in vitro. The aim of this study was to compare the occluding effect of Nd:YAG laser with that of sensodyne on exposed dentine. MATERIAL AND METHODS: Forty freshly extracted human maxillary anterior teeth were collected at random. Root canal obturations were performed using master apical file no. 60 k-type for obturated teeth. All teeth were stored in 100% humidity at 37 degrees C for 48h to allow time for the sealer to set. Dentine of 35 teeth was exposed by removing the cementum, and the remaining five teeth represented a negative control group. Specimens were examined using stereomicroscopy to show the surface topography of the dentine substrate before and after treatment with Nd:YAG laser or sensodyne. RESULTS: A double-blind technique was used when taking measurements of ink penetration (in mm) for each group. Teeth treated by Nd:YAG laser showed the least ink penetration, followed by teeth treated by sensodyne. The positive control group demonstrated complete ink penetration and the negative control group showed no ink penetration. Stereomicroscopic examination of specimens treated with Nd:YAG laser showed deposition on the dentinal surface, and specimens treated with sensodyne showed partial deposition. Untreated specimens were free of deposition and the tubules remained patent. CONCLUSION: There is no significant difference in the occluding effect of Nd:YAG laser and sensodyne toothpaste. Both treatments have a promising effect on the reduction of permeation through exposed dentinal tubules. However, the occluding effect of Nd:YAG laser occurs within seconds whereas that of sensodyne takes at least 3 weeks.
Asunto(s)
Dentina , Fluoruros/uso terapéutico , Terapia por Luz de Baja Intensidad/métodos , Nitratos/uso terapéutico , Fosfatos/uso terapéutico , Diente no Vital , Pastas de Dientes/uso terapéutico , Análisis de Varianza , Dentina/efectos de los fármacos , Dentina/efectos de la radiación , Dentina/ultraestructura , Combinación de Medicamentos , Humanos , Microscopía Electrónica de Rastreo , Permeabilidad , Diente no Vital/tratamiento farmacológico , Diente no Vital/radioterapiaRESUMEN
BACKGROUND: Recent years have witnessed an increasing emphasis on the role of nuclear DNA and its application in experimental pathological diagnosis to predict prognosis and management of certain neoplasm. AIMS: to establish objective criteria for the degree of differentiation and histochemical quantitative of nuclear DNA of oral squamous cell carcinoma (OSCC) using microspectrophotometric analysis. MATERIAL AND METHODS: The study was conducted on histologic materials from patient with OSCC. Two histological grading systems were used; Broder's and invasive front grading system were recorded. Microspectrophotometry was applied on Feulgen-stained sections to determine the quality of tumour nuclear DNA content in two different histological grading systems of OSCC. RESULTS: Nuclear DNA content increased significantly with decreasing tissue differentiation as well with increasing tumour size. CONCLUSION: The grading system and DNA content provides more objective and accurate criteria which relate the morphologic finding to biologic activity and growth patterns of oral cancer as compared to histologic differentiation alone.