RESUMEN
The purpose of this study was to compare morphological changes on the dentin surface induced by laser light delivered perpendicular or parallel to the dentin surface. The surface of the dentin slices and the root canal walls were lased with argon, CO2, and Nd:YAG lasers. When the laser beam was parallel to the dentin, the effects of the laser energy ranged from no effect to eroding and melting of the smear layer and dentin in the samples. When the laser beam was perpendicular to the surface, all three lasers produced well-shaped craters. From this, it was concluded that the angle of the laser beam in relation to the target surface can be a deciding factor of how much energy will be absorbed by the dentin and consequently of the morphological changes induced by the laser.
Asunto(s)
Cavidad Pulpar/efectos de la radiación , Dentina/efectos de la radiación , Rayos Láser , Argón , Dióxido de Carbono , Cavidad Pulpar/ultraestructura , Dentina/ultraestructura , Permeabilidad de la Dentina/efectos de la radiación , Humanos , Microscopía Electrónica de Rastreo , Neodimio , Capa de Barro DentinarioRESUMEN
The histological response of the dental pulp after laser irradiation was studied. After pulpotomy was performed in the premolar and molar teeth of dogs, the exposed pulp tissue at the root canal opening was lased using either a CO2 or Nd:YAG laser. The laser parameters were 2 W, 10 ms, 5 times per second for 1, 2 and 3 s for CO2 laser and 2 W, 20 pulses per second for 1, 2 and 3 s for the Nd:YAG laser. Observations were made 30 and 45 days after treatment. The results revealed that laser irradiation caused carbonization, necrosis, infiltration of inflammation cells, oedema and haemorrhage in the pulp tissue. Under the conditions of this experiment, there was little histological evidence of repair to the treated pulp with a newly formed dentine barrier, which was in contrast to the control samples treated with a calcium hydroxide-containing cement (Dycal).
Asunto(s)
Terapia por Láser/instrumentación , Pulpotomía/instrumentación , Animales , Pulpa Dental/patología , Perros , Estudios de Evaluación como Asunto , Terapia por Láser/métodos , Necrosis , Pulpotomía/métodos , Factores de TiempoRESUMEN
Calcium hydroxide preparations Ca(OH)2 are used as water solutions, putly, liner, cement or artificial material. The therapeutic effect of each medicaments depends on physical and chemical characteristic of additional components. The aim of the paper is to research the sensitivity of Streptococcus faecalis and Candida albicans to different water solution concentrations of calcium hydroxide. As solid plates, Bacto-Mitis-Salivarius agar was used for S. mutans, Torlak blood agar for S. faecalis and Sabourand agar "Torlak" for C. albicans. The holes were drilled in solid plates and were filled by 0.2 ml of water solutions of Ca(OH)2. Preparations, created as described were incubated aerobically at 37 degrees C in the period of 48 hrs. Results were read after 24 as well as after 48 hrs. The examined solutions of Ca(OH)2, revealed the highest antimicrobic effect after 24 hrs. The result remained unchanged even after 48 hrs. The inhibition of S. mutans growth on the solid plate occurred with the concentration of Ca(OH)2 solution from 271.18 x 10(-2) mol/dm3 and pH 12.76. The growth of S. faecalis at the solid plate was inhibited with the concentration of 3335.21 x 10(-3) mol/dm3 and pH 12.82. The inhibition of C. albicans growth on solid plate occurred with the concentration of Ca(OH)2 solution from 1023.20 x 10(-3) mol/dm3 and pH 12.84. The difference in the sensitivity of the examined microorganisms at the same concentrations of Ca(OH)2 solution was observed.
Asunto(s)
Hidróxido de Calcio/farmacología , Candida albicans/efectos de los fármacos , Enterococcus faecalis/efectos de los fármacos , Streptococcus mutans/efectos de los fármacos , Pruebas de Sensibilidad MicrobianaRESUMEN
We have analysed the filling length in 495 teeth, the length of which was measured with various methods routinously used in practice today. Significantly better fillings of root canals after pulpectomy were observed in the group, in which the length of canals was measured with odontometer, in comparison with the group, in which the lengths were measured with the tactile sense method (P less than 0.01), and with the group, in which the length was measured with preoperative radiogram only (P less than 0.05). The odontometric method resulted in statistically significant reduction of overfilled teeth in comparison with the x-ray measurement and with the radiogram made with the instrument in the root canal (P less than 0.01).