Bonding increased by the acid etching technique introduced

Bonding is a very important procedure for an orthodontist
which involves joining of two solid substrates by an intervening layer of
adhesive agent. The mechanical bonding between enamel and the resinous
restorative material has increased by the acid etching technique introduced by Bunocore1
in 1955. Phosphoric acid etching creates microporosities in the enamel
and resin gets mechanically interlocked into it. This fact is helpful for
bracket attachment, as the bulk of the resin gets retained in the enamel due to
the resin penetration into the tissue. Attachment of brackets to tooth surface
started with the arrival of this technique by using adhesive resin cements and
other adhesive materials. Direct bonding of orthodontic brackets introduced by Newman2
1965 was regarded as the first step in application of appliances.

On the other hand, debonding of orthodontic fixed
appliances is a critical point at the time of and at the end of fixed
orthodontic treatment. Many instruments and pliers have been used and evaluated
for debonding of brackets. Some specialized debonding pliers are also available
which are not manufactured for debonding but made specifically for this
procedure such as Weingart pliers, Howe pliers, and straight wire cutters to
facilitate debonding.3 Other methods can also be used for debonding
for example using ultrasound or laser application, electrothermic debonding, and
the use of bonding materials like thermoexpandable microcapsules. The purpose
of debonding is removal of these attachments from the tooth and restoring the tooth
surface, without iatrogenic damage as nearly as possible to its pre treatment
condition. To gain these goals, a correct technique is very important because
debonding is time taking and detrimental to the enamel if the technique used is
not proper or if performed in an unskillfull manner.4  The most common type of forces applied at
debonding are shear, tension, compression, and torsion (torque). But, many
factors are reported that can influence the terminal debonding strength value.
The force application type, magnitude, location, direction, and angulation are
some of the major factors affecting the final bond strength value.3

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Artun and Bergland used an Adhesive Remnant Index (ARI)
system to evaluate the amount of adhesive left on the tooth after debracketing.
This index system was developed on the basis of a pilot study of 20 extracted teeth.
Through the years, ARI scores have been one of the most frequently evaluated aspects
in studies on orthodontic adhesives. As, the ARI score system is qualitative and
subjective, attempts were made for modifying the original system and to develop
new quantitative methods to assess the adhesive remnant more accurately. Many
qualitative and quantitative methods are there to decide the ARI score on enamel
surface and bracket bases after bracket removal, like scanning electron microscopy,
visual inspection, stereomicroscopy, photography, 3-dimensional profilometry, and
visual inspection with photography under magnification and use of various stains.
If remnants are not satisfactorily detected, ARI scores can be inaccurate.5

With the evident of literature regarding etching,
composite, bond strength, debonding procedure and bond failure with their ARI
scores, the literature has not explained about the amount of pressure required
to be applied during bonding procedure and its role in bond strength. Also there
is need to determine the effect of pressure applied while bracket bonding on
debonding and adhesive remnant left over the tooth. It is also required to
screen the remnants of adhesive after debonding with use of stain for better
ARI scoring and removal after debonding procedure in the patient.