Effects of antibacterial capping agents on dental pulps of monkeys mechanically exposed to oral microflora.

The effects of antibacterial drugs on bacterially contaminated dental pulps were investigated in monkeys. Class V buccal cavities with pulpal exposures were prepared and then left open to the oral environment for 24 h. The exposed pulps were capped with alpha-tricalcium phosphate (alpha-TCP) containing a mixture of antibacterial drugs. Either alpha-TCP or Ca(OH)2 was used as a control. Pulpal responses were histologically evaluated after 4 wk. Those teeth capped with alpha-TCP alone showed total pulp necrosis and bacterial growth within the pulp chamber. By contrast, the pulps capped with alpha-TCP containing mixed antibacterial drugs remained almost normal without any necrotic layer, but showed persistent absorbing response to capping materials and no signs of hard tissue barrier formation. In teeth capped with Ca(OH)2, a hard tissue barrier was formed below the exposure site, with a wide loss of pulp tissue. No inflammation was seen under the barrier. These results indicate that mixed antibacterial drugs added to alpha-TCP effectively disinfected pulpal lesions, without destroying any of the sound pulp tissue. However, hard tissue barrier formation was delayed by this mixture as compared with Ca(OH)2.