O. Gokay et al., Penetration of the pulp chamber by bleaching agents in teeth restored withvarious restorative materials, J ENDODONT, 26(2), 2000, pp. 92-94
It is thought that externally applied bleaching agents may penetrate into t
he pulp chamber. This study was conducted to evaluate the diffusion of pero
xide bleaching agents into the pulp chamber of teeth restored with various
restorative materials. Sixty-five human extracted anterior maxillary teeth
were separated into the 13 groups containing 5 teeth. Five teeth (control g
roup) were not subjected to any cavity preparation and restoration. Standar
dized class V cavities were prepared in the other 60 teeth and restored usi
ng composite resin (Charisma), polyacid modified composite resin (Dyract),
or resin-modified glass ionomer cement (Vitremer). All teeth were sectioned
3 mm apical to the cementoenamel junction to remove the intracoronal pulp
tissue, and the pulp chamber was filled with acetate buffer to absorb and s
tabilize any peroxide that might penetrate. Vestibular crown surfaces of te
eth in the experimental groups were subjected to four different bleaching a
gents for 30 min at 37 degrees C, whereas the teeth in the control groups w
ere exposed only to distilled water. Then the acetate buffer solution in th
e pulp chamber of each tooth was removed, and the pulp chamber of each toot
h was rinsed with 100 ml of distilled water twice. Leukocrystal violet and
enzyme horseradish peroxidase were added to the mixture of the acetate buff
er and rinse water. The optical density of the resulting blue solution was
determined spectrophotometrically and converted into microgram equivalents
of hydrogen peroxide. Higher hydrogen peroxide concentrations resulted in a
higher pulpal peroxide penetration. The highest pulpal peroxide penetratio
n was found in resin-modified glass ionomer cement groups, whereas composit
e resin groups showed the lowest pulpal peroxide penetration.