Avaliação da variação de pH e da permeabilidade da dentina cervical em dentes submetidos ao tratamento clareador

Abstract

External cervical root resorption is one of the disadvantages of the bleaching procedure. There are several mechanisms that may be responsible for causing resorption, such as the chemical and physical action of the utilized materials and the morphology of the cementoenamel junction. The purpose of this study was to investigate the presence of a communication between the pulp chamber and the external root surface. The investigation was carried out by means of pH tests and measurement of dye infiltration into cervical dentin after the bleaching procedure. Thirty-four human permanent incisors were submitted to endodontic treatment. The teeth were assigned to three experimental groups, according to the level at which the filling was cut, and to the sealing of the root canal entrance with glass ionomer cement. Sodium perborate and 30% hydrogen peroxide were utilized for bleaching. pH readings were carried out after 30 minutes, 24 h, 48 h and 72 h from the beginning of the procedure. The teeth were immersed in 0.5% basic fuchsin for 24 h in order to determine possible differences in the permeability of cervical dentin. The results revealed that pH tended to change when the root filling was cut at the entrance of the canal, when 2 mm of the filling were removed, and when the canal entrance was sealed with glass ionomer. Dentinal permeability increased in the three experimental groups, in comparison with the control group. These slight differences may suggest a communication between the pulp chamber and the external root surface.

Infiltration of Rhodamin B into three materials used as cervical barrier

“…For this purpose, different types and concentrations of chemical agents are used, which must at all times be applied under the control and supervision of the dentist Non vital tooth bleaching is a conservative and esthetic alternative in the treatment of teeth darkened after endodontic treatment, offering greater preservation of tooth structure, at low cost when compared with more invasive procedures, such as fabrication of veneers or total crowns, restorative maneuvers or even the association of restorative and bleaching techniques [3][4][5][6][7][8][9] . Color changes in non vital teeth may occur due to a series of etiological factors, such as the occurrence of pulp hemorrhage caused by traumatisms; after pulpotomy or pulpectomy, in which the rupture of blood vessels allows penetration of erythrocytes into the dentinal tubules, and their hemolysis releasing hemoglobin; inadequate coronal access, with the permanence of areas of retention such as the roof; penetration product resulting from pulp tissue decomposition into the dentinal tubules; the presence of filling material remainders in the root canal, and medications used in endodontic treatment in the pulp chamber [4][5][6][7][8][9] .…”

“…Color changes in non vital teeth may occur due to a series of etiological factors, such as the occurrence of pulp hemorrhage caused by traumatisms; after pulpotomy or pulpectomy, in which the rupture of blood vessels allows penetration of erythrocytes into the dentinal tubules, and their hemolysis releasing hemoglobin; inadequate coronal access, with the permanence of areas of retention such as the roof; penetration product resulting from pulp tissue decomposition into the dentinal tubules; the presence of filling material remainders in the root canal, and medications used in endodontic treatment in the pulp chamber [4][5][6][7][8][9] . Loguercio et al 3 affirmed that irrespective of the causal factors, all professionals must be well prepared to correctly diagnose the cause of color changes, because this is an indispensable condition for successful bleaching treatment.…”

Ex vivo evaluation of the effectiveness of bleaching agents on the shade alteration of blood‐stained teeth

“…Utilization of hydrogen peroxide for bleaching of root filled teeth has been associated with undesirable side effects, such as external cervical root resorption (Harrington & Natkin 1979), increased dentinal permeability (Dezotti et al 2002) and alterations in the chemical structure of dentine (Rotstein et al 1992).…”

“…Hydrogen peroxide, when in an acidic medium, breaks down into oxygen ions and hydroxyl free radicals, whereas in an alkaline medium (between 9.5 and 10.8) it produces hydroperoxyl free radicals that are oxidizing, improving the bleaching effect (Goldstein & Garber 1995, Sun 2000. Utilization of hydrogen peroxide for bleaching of root filled teeth has been associated with undesirable side effects, such as external cervical root resorption (Harrington & Natkin 1979), increased dentinal permeability (Dezotti et al 2002) and alterations in the chemical structure of dentine (Rotstein et al 1992).…”

Avaliação da limpeza das paredes dos canais radiculares e da permeabilidade dentinária, após o uso da solução de EGTA isoladamente, ou sem associação com tensoativos

“…Os resultados mostraram que a irrigação final com o gel Carisolv ou com a solução de EDTA-T, promoveu um aumento significativo da permeabilidade da dentina radicular, sendo que, no terço apical, o aumento foi de menor intensidade. NISHIYAMA43 , em 2002, avaliaram a permeabilidade da dentina cervical em dentes tratados endodonticamente, submetidos ao clareamento interno com perborato de sódio e peróxido de hidrogênio a 30%. Após a obturação, os dentes foram divididos em grupos de acordo com o nível de corte do material obturador e selamento, ou não, da embocadura dos canais com ionômero de vidro.…”