The purpose of this study was 2-fold to: 1) evaluate in vitro the surface texture of titanium implant abutments after exposure to plastic scalers, an air-powder abrasive system, rubber cup polishing with flour of pumice, and untreated control abutments; and 2) compare plaque accumulation in humans on abutments treated with the above methods. In part I, 5.5 mm abutments were instrumented for 30 seconds per 90 degrees segment with the respective methods. The surface character was compared to untreated controls using SEM at 260X magnification. The control abutments revealed prominent milling marks and small pits; plastic scalers slightly smoothed the milling marks and created microscratches; the air-powder abrasive largely obliterated the milling marks and caused some surface pitting; the rubber cup with flour of pumice removed the milling marks and created a smooth swirl pattern. None of the instrumentation appeared to roughen the surface. In the clinical experiment (part II), four abutments, one of each type, were placed in 12 patients for a period of 7 days, during which the patients performed no oral hygiene. At the end of 7 days, the abutments were retrieved and processed for SEM. A digitizer and software program were used to determine the percent of total abutment surface area covered by plaque. The demarcation of supragingival and subgingival plaque was well delineated. The total mean percent surface area of plaque ranged from 52.06% for the air-powder abrasive to 55.29% for the plastic scalers.(ABSTRACT TRUNCATED AT 250 WORDS)