Interproximal enamel reduction

Interproximal Enamel
Reduction
www.indiandentalacademy.com

Interproximal enamel reduction (IER): is
understood to be the clinical act of removing part
of the dental enamel from the interproximal
contact area

The aim of this reduction is to create space
for orthodontic treatment and to give teeth a
suitable shape whenever problems of shape or
size require attention

In the literature, this clinical act is normally referred
to as:
 stripping,
 slandering,
 slicing,
 Hollywood trim,
 selective
 grinding,
 mesiodistal reduction,”
 reapproximation,
 interproximal wear,
 coronoplastia.

IER treatment should be considered as an
exact reduction of interproximal enamel and not
just as a simple method to solve problems.

HIISTORY OF IINTERPROXIIMAL
ENAMEL REDUCTION
Interproximal dental stripping has been
used by orthodontists for many years. It was
initially used to gain space when correcting
mandibular incisor crowding or to prevent such
crowding

 Ballard 1944 : recommended a careful
stripping of the interproximal surfaces,
mainly from the anterior segment, when a
lack of balance is present.

 Begg (1954): published his study of Stone Age man’s
dentition, where he referred to the shortening of the
dental arch over time, which occurred through abrasion.
Although the degree of shortening of the dental arch
found by Begg was contested, the existence of this
natural reduction led to the publication and development
of the technique for interproximal enamel reduction.

 Hudson 1956 :stated that stripping should be carried
out with medium and fine metallic strips, followed by final
polishing and topical application of fluoride). He stated
that it was possible to gain 3 mm of space between
mandibular canines,and presented an enamel thickness
table for incisor and mandibular canine contact points

 Bolton 1958: This study, together with Ballard’s study,
supported the need, in dental dimension discrepancy
problems, to use interproximal stripping to correct
problems ofdental balance.

 Kelsten 1969 : recommended the use of mechanical
means to carry out stripping and recommended prior
alignment of teeth. He posited that only after alignment
could stripping be simply and accurately achieved.

 Rogers and Wagner: describerd if the extracted teeth
were treated with fluoride after stripping, they offered
greater resistance to acid attacks, mainly in the 48 to 96
hours after the procedure. This scientifically justified the
importance, already highlighted by Hudson, of topical
fluoride application after stripping and polishing.

 Paskow 1971: recommended the use of mechanical
methods of IER.
 Shillingbourg and Grace 1973: important study on
enamel and dentin thickness which became basis for
work on stripping and allowed the amount of enamel that
could be safely removed from each dental face to be
accurately determined

 Peck and Peck ‘70s: Presented the Peck index.
They advised stripping whenever the mesiodistal
dimension of the mandibular incisors did not fall within
acceptable figures calculable from their index.They
claimed that anything in excess would constitute
predisposition toward crowding

 Tuverson 1980 published :which presented a
highly detailed description of the stripping
technique using a back angle and abrasive
disks.
 Doris, Bernard, and Kuftinec 1981 :concluded
that one of the strongest determining factors for
dental crowding is the dimension of teeth in the
arch.
 ,Betteridge 1981 : presented the results of
stripping on the anterior and inferior segment
after 1 year without retention.

 Sheridan 1985: published his article “Air-rotor stripping”
These articles totally revolutionized the technique and aims
of interproximal enamel reduction.
He recommended:
1. Use of a turbine with carbide drill, instead of
diamond disks and strips.
2. Stripping on buccal sectors; in other words, distally
on canines or mesially on the second molars on both
arches. This achieves greater space and allows the
preservation of incisors.
3. Use of stripping procedures to achieve space (up
to 8 mm per arch) for the correction of moderate
dentomaxillary disharmony, without recourse to
extraction or excessive expansion

 Zachrisson 1986 :proposed a new direction
for stripping improvement of the shape of the
teeth, mainly for incisors and reduction of the
black triangular space above the papilla

INDICATIIONS
The IER technique has evolved over the years; it
was first used only for stripping mandibular incisors, with
the aim of preventing and correcting crowding. Areas of
application have continued to grow.

1. Tooth size discrepancy. In 1944, Ballard recommended careful
stripping of the proximal surface of the anterior teeth when there
was imbalance.
2. Crowding of mandibular incisors Stripping was first used to obtain
space for the correction and prevention of crowding.
3. Tooth shape and dental esthetics. Stripping can and should be used
for the reshaping of enamel on some teeth, thus contributing to an
improved finishing of orthodontic treatment and dental esthetics

4. Normalization of gingival contour and elimination of triangular spaces above
the papilla, thus greatly improving esthetics and smile.
5. Moderate dentomaxillary disharmony. This is a primary area of application for
interproximal enamel reduction in the technique developed by Sheridan in
1985 and 1987, which allowed space to b obtained for the correction of
moderate dental crowding; up to 8 mm per arch could be achieved without
the need for extraction or excessive expansion.

6. Reduced expansion and premolar extraction.
7. Camouflage of Class II and III malocclusions. Theuse of mandibular
stripping can be beneficial incamouflaging slight to moderate Class
III conditionsand overjet. In orthodontic treatment to
camouflageClass II with the extraction of two maxillarypremolars,
correcting the crowding and inclinationof the mandibular incisors
with stripping is anideal solution.
8. Correction of the curve of Spee. For the correctionof an exaggerated
curve of Spee, it is necessary tocreate a few millimeters of space in
the arch. This can be achieved through moderate stripping.

CONTRAIINDIICATIIONS
 There are several contraindications for the approximation technique:
1. Severe crowding (more than 8 mm per arch). With application of IER, it
would be hazardous to carry out orthodontic correction. There would be risk
of excessive loss of enamel and all of the ensuing consequences.
2. Poor oral hygiene and/or poor periodontal environment. IER should not be
used when there is active periodontal disease or lack of dental stability.

3.Small teeth and hypersensitivity to cold. Stripping should not be used
in these situations, as the risk of the appearance of or an increase in
dental sensitivity is great.
4. Susceptibility to decay or multiple restorations. There is a risk of
causing imbalance in unstable oral situations,
5. Shape of teeth. Stripping should not be carried out on “square” teeth
teeth with straight proximal surfaces and wide basesas these
shapes produce broad contact surfaces, and could potentially cause
food impaction and reduced interseptal bone

MATERIIAL AND METHODS
Correct IER is composed of four stages:
 reduction,
 reshaping,
 polishing, and
 protection of the enamel

There are two main techniques for IER,
depending on whether manual or mechanical
methods are used.

Manual method
 This method consists of metallic strips, impregnated with
abrasive metal oxides, and numerous holding devices .
 This method was first described in the
literature by Hudson.

The technique is seldom used for three reasons:
(1) It is time consuming;
(2) There is technical difficulty in working on posterior
teeth; and
(3) It causes much deeper grooves on the abraded enamel
than those caused by mechanical instrumentation.

Mechanical method
This technique greatly reduces working time. The
tools for its use mainly consist of disks for handpieces or
contra-angles, high-speed handpieces, and mechanical
files for contra-angle heads with shuttle movement

Tools for the mechanical method of IER.
(a) Disks for handpieces,
(b,c) mechanical files for contra-angle heads with shuttle movement.

Van Waes and Matter have developed an “orthostrips system” of
flexible strips for contra-angle shuttle heads composed of four small
metallic strips of decreasing grain size

Techniques
Initially, stripping was done as described by Hudson,
with metallic strips . Hand disk contra-angles were
introduced later, and are recommended by anumber of
authors
(Left) Manual stripping with small metallic strips.
(RIght) Stripping with disks.

In 1985, Sheridan advised the use of carbide
fissure drills for turbines, cutting from a horizontal
position and parallel to a 0.022-inch wire, called an
“indicator wire,” which was previously positioned at the
gingival margin .
(a) Indicator wire and (b) the Sheridan stripping technique

For the shaping and finishing of the tooth, Sheridan
recommended a finegrain diamond drill. Other authors
have recommended very fine diamond drills, used
vertically, which facilitate the shaping movement and
reduce the risk of causing the formation of steps
Stripping technique with avery fine diamond drill, used vertically

Zhong and colleagues: have concluded that stripping
executed with perforated disks, followed by polishing
with fine and ultra-fine Sof-Lex disks, proved to be
efficient and provided good results in final polishing

The four metallic strips in the van Waes and Matter
ortho-strips system, with grains between 15 and 90 μm
for cutting and polishing, can be adapted to a 36-position
shuttle head with oscillation movement of 0.8 mm.

They have the advantage of being flexible and
adapt well to the shape and convexity of the tooth,
especially at the contour of cervical area
Files for use with shuttle heads are available in several different grains (15
to 125 μm) for cutting and polishing. They are also practical for shaping
teeth

Treatment sequence
The following treatment steps are described in more detail below.:
1. Complete treatment planning, with accurate measurement of study
casts.
2. Ensure that no contraindications to IER exist.
3. Place orthodontic appliances and correct rotation.
4. Place elastic or spring separators.
5. Carefully do the IER (carried out sequentially).
6. Shape and polish the stripped surface.

7. Measure and control the obtained space.
8. Check posterior anchorage.
9. Reduce friction and perform the progressive distalization.
10. Apply fluoride.
11. Align anterior teeth.
12. Retain properly to maintain optimal results.

For sound practice of this technique, the first step
should be to plan the treatment and accurately measure,
on the study casts, the amount of space required for the
desired correction .

A few days before stripping, separators are placed in position or a
spring is placed to separate each tooth at the contact area. This has the
advantage of allowing stripping to be carried out individually on each
tooth.
(a) separators are placed in position or (b) spring is used to separate teeth,
and (c) measurement of the space is obtained with the spring or separator

IER and polishing are then carried out on the mesial
surface of the last tooth to be stripped and on the distal
surface of the penultimate tooth.

The space obtained is measured with the instrument
or with calibrated wires, as recommended by Philippe .
Anchorage of the posterior teeth is then prepared, which
can be done with stops , bends in the arch, or through the
prior fitting of palatal and lingual bars
(a)Calibrated wires, as recommended by Julien Philippe.
(b) Instrument recommended by Sheridan
(c) Anchorage of the posterior teeth with stops.www.indiandentalacademy.com

Distalization should be carried out tooth by toothto avoid any
loss of space. The archwire should slide freely in the brackets, so
round steel arches arerecommend. Brackets with a ball hook can
also be used, which allows the fitting of a metallic ligature to the
bracket and force application at that point.
(a)Distalization elastic placed on bracket and
(b) distalization elastic placed on a ball hook

At the end of each stripping and polishing session, a topical
application of fluoride should be performed.
Fluoride ready for topical application.

When distalization of the tooth is finished, the
whole process is repeated in the next contiguous space .
When the stripping and distalization stages are
complete, a nickel-titanium or thermoactive arch is
placed, followed by alignment of the anterior teeth.

Figures illustrate, with pre- and posttreatment photographs,
the results achieved with proper IER technique in two patients with
Class I malocclusion and moderate crowding.

Advantages of IER
The following are the main advantages of the IER technique:
 Treatment time is reduced.
 The quality of treatment is significantly improved I patients
with crowding and contraindications for extraction, as in the
case of closed bites.
 Esthetics are improved, as is the final health of the gingival
papilla, which adapts better to a reduction of interdental
space than to the space left by extraction.
 Treatment of adults with slight or moderate crowding is
possible, without the need for extraction.
 Greater posttreatment stability is possible.

 The space obtained can be continuously monitored to
adjust it to the space needed to achieve the treatment
goals.
 Overexpansion of the dental arch is avoided.
 Extraction of teeth is greatly reduced.
 The need for excessive tooth movement, as well as the
possible loss of bone and of root cementum, is reduced
due to the fact that the iatrogenic potential is considered
less than with extraction

 Disadvantages of IER
 It is a time-consuming treatment.

KEY POIINTS
•Carry out stripping sequentially.
•Limit stripping to 0.5 mm per contact
surface or, in other words, 1 mm per
mesial contact area second molars to the
distal of the canines.
•Measure space accurately.

•Parallel stripped contact areas.
•Shape dental surfaces to their original
configuration, without abraded grooves.
•Carefully polish the stripped surface.
•Topically apply fluoride after stripping.
•Reduce, as much as possible, inadvertent loss of
space obtained, by using anchorage on
posterior teeth and reducing friction through the
use of round arch and metallic ligatures.

CONCLUSIION
 It has been shown that orthodontists can
effectively
 use the IER technique in many aspects of their
practices.
 There is no evidence that IER conducted within
 recognized limits and in appropriate situations
 causes harm to teeth or gingiva.

Thank you

Interproximal enamel reduction

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