Mechanical and chemical root preparation in vitro: efficiency of plaque and calculus removal

The aim of this investigation was to compare the effectiveness of several different methods of root instrumentation by measuring and comparing the amount of residual stained material following treatment. Also, 2 different methods of quantitating residual stained material were compared. A total of 90 periodontally-involved teeth were extracted and randomly assigned to 1 of 8 treatment groups or to the untreated control group. Experimental treatments consisted of one or a combination of the following: Columbia 13-14 curet, P-10 ultrasonic instrument, diamond-coated P-10 ultrasonic instrument, or antiformin/citric acid chemical treatment. Selected samples were examined using light microscopy in order to determine the amount of cementum removed during root instrumentation. Residual stained material was quantitated using a method of grid-square analysis as well as by the use of photographs and a digitizing tablet. Following instrumentation, it was noted in histologic sections that the complete removal of cementum was rare, although all of the cementum was removed by some experimental treatments in some areas. All mechanical methods of root instrumentation were found to be essentially equal in effectiveness with respect to the removal of plaque and calculus. Chemical debridement alone was found to be ineffective. It was further noted that the grid-square method of analysis produced measurements that were 2 to 8 times higher than measurements produced by the digitizing tablet.