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

SONO-ABRASION

SONO-ABRASION

INTRODUCTION
A recent development from the original ultrasonics ,is the use of
high-frequency, sonic, air-scalers with modified abrasive tips – a technique known
as ‘sono-abrasion’

The Sonicsys micro unit, designed by Drs Hugo, Unterbrink and
Mösele

Sono-abrasion is based upon the Sonicflex 2000L and 2000N air-scaler handpieces that oscillate in the sonic region (< 6.5 kHz)

WORKING PRINCIPLE

Sono abrasion technique is based on the removal of tooth material by an air-driven hand piece equipped with a diamond-coated working tip that removes tooth material by ultrasonic kinetic energy.

sono-abrasion has been introduced as an alternative for preparing minimally invasive cavities .

Sono abrasion technique was initially developed to prepare predetermined cavity outlines but also works well in removing hard tissue when finishing cavity preparation.

DIAMOND TIPS
Different sizes and shapes of diamond tips have been designed.
There are three different instrument tips:
lengthways halved torpedo shape (9.5 mm long, 1.3 mm wide),
small hemisphere (1.5 mm diameter) and
large hemisphere(2.2 mm).

As these tips are coated only on one side, additional damage and trauma of the approximal side of adjacent teeth is prevented.

The constricted shape of the tip enables easy access in small occlusal and approximal cavities.

Sono-abrasion can be used for beveling the cavity margins, thereby improving the marginal adaptation of a composite filling