SONO-ABRASION 2

TIP MOTION

The tips describe an elliptical motion with a trans verse distance of between 0.08 – 0.15 mm and a longitudinal movement of between 0.055 – 0.135 mm.Diamond coated on one side using 40 μm grit diamond and are cooled using water irrigant at a flow rate of between 20–30 mL /min.

Considering the semi-rotary movement of the tip, the very high frequency of oscillations of the tip and the subsequently produced heat, dentin exposed by sono-abrasion can also be assumed to be covered by a smear layer.

LIMITATION

The torque applied to the instrument tips should be in the region of 2 N.
If the applied pressure is too great, the cutting efficiency is reduced due to damping of the oscillations

STUDIES

Van Meerbeek et al found that sono-abrasion resulted in enamel and dentin surfaces equally receptive towards bonding as compared with bur-cut surfaces, they also found that a three-step etch-and-rinse adhesive (Optibond) with omission of the acid-conditioning phase obtains higher bond strengths when bonded to sono-abraded dentin than to bur-cut dentin.
This was explained by the relatively high acidity of the primer of Optibond FI. (pH= 1.78), which thus acts as a self-etch adhesive, and by the fact that sono-abrasion presumably produces rather thin smear layers.


Pioch et al. investigated the interface of an etch-and-rinse adhesive with confocal laser scanning microscopy and did not see any difference between bur-prepared or sono-abraded dentin of primary teeth.

Opdam et al.| reported equal microleakage in class-II cavities prepared by bur or SonicSys, respectively. Their study was confirmed by the findings of Setien [57].

Minimally Invasive Technique
Sono-abrasion should be regarded as a good complement to rotary instruments for cavity preparation, the main advantages being less damage to adjacent teeth and minimally invasive cavities. A sono-abraded dentin surface is also covered by a thin smear layer.

Dentine caries excavation: a review of
current clinical techniques
Banerjee,1 T. F. Watson,2 and E. A. M. Kidd,3
BRITISH DENTAL JOURNAL VOLUME 188. NO.9 MAY 13 2000 476-482