Pain and discomfort levels in patients during root surface debridement with sonic metal or plastic inserts

The study was designed to evaluate whether root surface debridement with a sonic scaler plastic insert would cause less pain and discomfort to patients than an ordinary, probe-shaped metal sonic insert. One quadrant in each of 23 patients was debrided with each insert. Blood pressure, mean arterial pressure, and heart rate were monitored before, during, and immediately after each treatment. Pain was also evaluated on a visual analogue scale (VAS) after each treatment, as well as 2 weeks later following pain-provoking stimuli. Blood pressure, mean arterial pressure, and heart rate did not reveal any differences between quadrants treated with plastic or metal inserts. Heart rate had a weak, positive association with treatment time. The VAS gave a higher pain score for the plastic (30.8) than for the metal insert (24.4), but this difference was not statistically significant (P = 0.055). Following pain-provoking stimuli at the 2-week follow-up visit, quadrants debrided with the metal insert (31.3) scored significantly lower (less pain) (P < 0.01) on the VAS than quadrants treated with the plastic insert (30.7). It is concluded that the sonic metal insert caused less pain and discomfort to the patients due to its superior accessibility and water spray cooling. The significant difference between metal and plastic tip debrided quadrants at the follow-up visit was probably caused by the smearing effect of the metal insert with partial closure of the dentin tubule orifices.