Indirect bonding is a technique where orthodontic brackets are bonded to a model of the patient's teeth rather than directly on the teeth. This allows for precise placement of the brackets. In the indirect technique, brackets are bonded to dental casts using adhesive. Then a template is used to transfer the brackets from the model to the patient's mouth. This eliminates problems with inconsistent bonding times and excess adhesive associated with direct bonding. However, some studies found direct bonding had fewer failures and better fit of brackets. A later indirect technique used composite resin to bond brackets to models, then a thin layer of unfilled resin was used to bond to teeth. This helped standardize bonding times and amounts of adhesive used.

1. INDIRECT BONDING
INTRODUCTION
Tooth movement is made possible by an orthodontist by applying
optimal force to the teeth. This optimal force is applied using
archwire, springs, loops, and elastics etc. for this force to be
transferred to the teeth, a rigid attachment on the tooth is required,
which is the bracket. The bracket is held on to the tooth either with
the help of bands or by means of bonding technique, bands were
adapted for each tooth and the brackets were welded on to them. The
bonding technique had several advantages and disadvantages when
compared to the bonding procedure.
Orthodontic brackets were first bonded directly to teeth more
than 20 years ago.1 The technique has been modified and refined since
then and has been so widely adopted that it might be said to have
become part of the standard of care for fixed appliances. The vast
majority of orthodontists bond at least the anterior teeth. Indirect
bonding, introduced in 1972 seemed to offer further advantages but it
was not without its problems. Although chair time and accuracy in
bracket positioning seemed excellent, the adhesives used either
required activation by ultraviolet light or beset the procedure with the
inconsistent setting times of chemical activation. The latter caused
operator stress because there was always the risk that either the
adhesive would begin to set before the template was seated or it would
not set by the time the template was removed. Applying just the right

2. amount of adhesive to attach the brackets to the teeth involved
guesswork with all of the adhesive systems, so adhesive voids and
excess were common. Zachrisson and Brobakken compared direct and
indirect bonding and concluded that direct bonding had fewer failures,
allowed easier flash removal, and yielded brackets more closely fitted
to the tooth surface with fewer voids.
Thomas introduced an indirect-bonding technique that seemed to
correct those deficiencies and perhaps simplify posttreatment
debonding also. Composite resin was used to attach the brackets to
models that were coated with a liquid separating medium. This
allowed the brackets to be positioned accurately-against the teeth with
just the right amount of adhesive. When set, the adhesive formed in
effect a custom-fit bonding pad for each tooth. Two-part unfilled resin
was then used to bond to the teeth. A thin coat of one part was applied
to the set composite resin on the bonding pads and a thin coat of the
other part was applied to the teeth. Thus the problems of working time
and amount of adhesive were virtually eliminated. It seemed
reasonable to hope that at debonding the unfilled resin layer would
fracture so most of the composite resin would be removed with the
bracket, rather than remaining on the tooth as was usually the case
with other techniques. On the other hand, there was the possibility that
the discrete film of unfilled resin might decrease the bond strength.

3. REVIEW
 The introduction of the acid etch bonding technique has led to
dramatic changes in the practice of Orthodontics. The increased
adhesive produced by acid pretreatment, using 85% phosphoric
acid, was demonstrated in 1955 by Buonocose (Journal of Dental
Research – 1955)
 In 1965, with the advent of resin bonding, Newman began to apply
these findings to direct bonding of orthodontic attachments. – (AJO
– 1965)
 In 1968, Smith introduced polyacrylate (Carboxylate) and bracket
bonding with this cement was reported. (- British Dental Journal –
1969)
 Around 1970, several articles appeared on bonding attachments
with different adhesives. The most widely used resin, commonly
referred to as …. resin or Big-GMA was designed to improve bond
strength and increase dimensional stability by cross -linking.
 The indirect bonding technique was originated by Dr. Silverman
and Cohen in 1972 – AJO.

4. Type of Bonding:
Bonding is broadly divided into 1. Direct 2. Indirect
In direct bonding, the brackets are attached to the tooth is the
correct mesiodistal and occlusogingival heights, with proper
angulations, using either a
a. Chemical curved or
b. Light curved composite
c. Glass Ionomer cement
With the indirect bonding technique, brackets are fixed to the
tooth in the working casts and then transfers to the patients’ mouth
with the help of an impression tray, which is usually made of silicone.
To list, the advantages of bonding are:
1. Esthetically superior
2. Faster and simpler
3. Less discomfort to the patient (no separation and band seating)
4. Arch length is not increased by band material
5. Bonds are more hygienic than bands, therefore, an improved
gingival and periodontal condition is possible, and better access
for clearing is a….
6. Mesiodistal enamel reduction is possible during treatment
7. Interproximal areas are accessible for composite build-ups, when
indicated.
8. Caries risk under loose bands is eliminated interproximal caries
can be detected and treated.
9. No band space area present to close at the end of treatment.

5. 10. No large inventory of bands is needed.
11. Lingual brackets, invisible braces, can be used when the patient
rejects visible orthodontic appliances.
12. Brackets may be recycled further reducing the cost.
However, some disadvantages of bonding are present:
2. Weaker attachment than in cemented band.
3. Gingival problems when the excessive adhesive extends beyond
the bracket base.
4. The protection against intrerproximal caries provided by well-
contoured bands is absent.
5. Rebonding a loose bracket required more preparation than re-
cementing a loose band.
6. Rebonding is more time consuming than debanding because
removed of adhesive is more difficult then removal of the cement.