EFFECT OF TETRACYCLINE HCL ON PERIODONTALLY-AFFECTED HUMAN ROOT SURFACES

SCANNING ELECTRON MICROSCOPY was used to evaluate surface characterist ics of periodontitis-exposed instrumented human cementum and dentin su rfaces following topical application of tetracycline HCl (TTC). Specim ens were randomly assigned to application of sterile saline for 1 minu te (control); TTC (10 mg/ml) for 1 minute and 4 minutes, respectively; and TTC (100 mg/ml) for 1 minute and 4 minutes, respectively. Solutio ns were applied with a cotton pellet using a burnishing technique. Con trol specimens exhibited an amorphous irregular surface smear layer. T TC treatment of cementum for 1 minute resulted in a relatively debris- free, nonhomogeneous surface. The 4-minute application resulted in a s urface exhibiting a densely fibrillar, matlike texture. Dentin specime ns conditioned for 1 minute showed a smooth surface with many tubule o penings partially occluded by debris. The 4-minute treatment exposed a 3-dimensional network of intertubular and peritubular collagen fibril s. No consistent morphologic differences were observed between cementu m 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 co ncentration of the drug.