Bacteria and pulpal reactions under silicate cement restorations

Silicate cement was inserted in deep unlined cavities in 70 human teeth; 35 cavities were cleaned with an antibacterial cleanser, and the other 35 cavities in the contralateral teeth were treated with water spray only. In all teeth, invasion of bacteria from the tooth surface was prevented with a surface seal. Histologic examinations after 4 weeks revealed bacterial growth on dentinal walls in 9 of the uncleaned and in 2 cleaned cavities. Only in these 11 teeth was an inflammatory reaction seen in the pulp. Under eight cavities without bacterial growth and with silicate cement placed directly on an exposed pulp, no serious injury and no inflammatory reactions were observed. It was concluded that silicate cement per se does not seriously irritate the pulp. Infection of cavity walls should be avoided, not only by removing grinding debris and antibacterial cleansing, but also by use of a liner to prevent invasion of bacteria from the surface of the tooth.