Comparison of Tooth Structure Removed with Curette and Ultrasonics

Objective:

Both hand instruments and ultrasonics are widely used during the initial phase of periodontal treatment and maintenance with the use of each varying with the preference of the clinician.  The literature compares the results of both methods in reducing periodontal disease and describes the differences in surface characteristics, but does not discuss the relative amount of tooth structure removed with each method.  The purpose of this study is to investigate the amount of tooth structure removed by both methods over a simulated time span of roughly five years. 

Method:

Eight single root teeth were selected and hydrated in deionized water.  Each tooth was dried for thirty seconds, weighed, rehydrated, and reweighed, for a total of three measurements, then averaged.  One side of the tooth was root planed for five minutes with a 3-4 Gracey curette, rehydrated, then weighed as before in triplicate.  An ultrasonic was used on the opposite side of the tooth root for five minutes with a Dentsply Bobcat Cavitron using a 25K slimline tip at a medium setting.  The tooth was rehydrated and weighed in triplicate.  Five minutes was chosen because this approximated the time spent root planing/using ultrasonics over a 5 year period of 3-month recalls. 

Result:

The mean amount removed by root planing was 0.0122 grams.  The mean amount removed using ultrasonics was 0.0055 grams.  Root planing removed 2.2 times more root structure than using ultrasonics, a difference confirmed to be statistically significant using a paired T test (P value 0.047). 

Conclusion:

If the results of both methods are similar as far as plaque/calculus removal and reduction in periodontal inflammation/probing depth, then the procedure that removes the least tooth structure would have an advantage. From our results, the use of ultrasonics appears to remove the least amount of tooth structure.