Effect of tetracycline HCl on periodontally-affected human root surfaces

Scanning electron microscopy was used to evaluate surface characteristics of periodontitis-exposed instrumented human cementum and dentin surfaces following topical application of tetracycline HCl (TTC). Specimens were randomly assigned to application of sterile saline for 1 minute (control); TTC (10 mg/ml) for 1 minute and 4 minutes, respectively; and TTC (100 mg/ml) for 1 minute and 4 minutes, respectively. Solutions were applied with a cotton pellet using a burnishing technique. Control specimens exhibited an amorphous irregular surface smear layer. TTC treatment of cementum for 1 minute resulted in a relatively debris-free, nonhomogeneous surface. The 4-minute application resulted in a surface exhibiting a densely fibrillar, mat-like texture. Dentin specimens conditioned for 1 minute showed a smooth surface with many tubule openings partially occluded by debris. The 4-minute treatment exposed a 3-dimensional network of intertubular and peritubular collagen fibrils. No consistent morphologic differences were observed between cementum or dentin specimens treated with TTC at concentrations of 10 and 100 mg/ml, respectively. The results suggest that topical application of TTC produces morphologic alterations of periodontitis-exposed cementum and dentin that appear related to application interval rather than concentration of the drug.