The penetration of lavage solution into the periodontal pocket during ultrasonic instrumentation

The purpose of this study was to evaluate the penetration depth of the water coolant for medicament lavage of an ultrasonic device into the periodontal pocket. Patients having teeth previously planned for extraction, and exhibiting probing depths 3 mm or greater were used in this study. A reference notch was placed on the tooth at the level of the gingival margin and the probing attachment level (PAL) was measured from the base of the notch to the base of the pocket. The ultrasonic device, with an EWPP tip and equipped with a reservoir of erythrocin dye colored coolant, was activated and moved in a vertical direction from the gingival margin to the apical extent of the pocket. The tooth was extracted and the penetration depth (PD) of the dye-colored water spray was measured from the reference notch to the apical limit of the stained subgingival plaque. The tooth was counter stained with methylene blue to determine the coronal extent of the connective tissue attachment. Pearsons' Product Moment Correlation Coefficient for the PAL and PD was calculated. Dye-stained root surface was observed along the full extent of the probe tip's penetration path. The dispersion of the dye-colored stain was localized to the area of the ultrasonic probe with very little lateral dispersion. The ultrasonic instrument may be an effective system to mechanically remove plaque and calculus at the same time as delivering a chemotherapeutic agent. The limited dispersion of the liquid dye would indicate that chemical plaque control with this delivery system is dependent upon thorough debridement with the instrument such that all affected surfaces are instrumented.