A histopathological study was attempted in order to investigate the pulpal response to diammine silver fluoride.
Cavity preparation was performed on 103 healthy permanent teeth of mongrel dogs with an air turbine and a carbide-bar with water spray. The specimens were divided into 2 groups. In the experimental group,0.01 ml 38% diammine silver fluoride (Ag(NH3)2F) solution was applied on the dentin for 3 minutes after the cavity preparation. In the control group, nothing was applied on dentin. All the dentin cavities of these groups were left open to the oral environment without any restoration.
The specimens were processed for histopathological evaluation at 3,7 and 30 days. The teeth were fixed in 10% neutral buffered formalin, embedded in celloidin, serially sectioned through the pulp and stained with hematoxylin and eosin.
The following observations were obtained.
1. Various histopathological changes such as necrosis, suppurative inflammation, round cell infiltration, bleeding, hyperemia, atrophy and vacuolization of pulps, and atrophy, loss and separation on odontoblastic layers, and destruction of predentin were observed in the experimental group and the control group. Apposition of dentin on the pulp chamber wall was observed in 11 cases (61.1%) out of 18 cases in the experimental group and in 7 cases (63.6%) out of 11cases in the control group of 30 days specimens.
2. In the experimental group, there was a 75% success ratio, a 20% fairly success raito and a 5% failure ratio in 3 day specimens, and a 73.9% success ratio, a 26.1 % fairly success ratio and a no failure ratio in 7 day specimens, and a 66.7% success ratio, a 22.2% fairly success ratio and a 11.1 % failure ratio in 30 days specimens.
3. In the control group, there was a 60% success ratio, a 26.7% fairly success ratio and a 13.3% failure ratio in 3 day specimens, and a 75% success ratio, a 25% fairly success ratio and a no failure ratio in 7 day specimens, and a 72.7% success ratio, a 18.2 % fairly success ratio and a 9.1 % failure ratio in 30 days specimens.
4. The above histopathological evaluations showed no significant differences between the experimental group and the control group.
5. There was no relation between the depth of silver particles included in Ag-(NH3)2F into dentinal tubles and the histopathological observations and evaluations.
6. Application of 38% Ag(NH3)2F did not show any protective efficacy to dental pulp.