The stability of treatment outcome in orthodontics remains a fundamental issue of concern and debate. Usually a retention phase is required after active Orthodontic tooth movement to maintain the ideal aesthetic and functional relation and prevent the teeth to return to their former position. In the importance of retention in orthodontic treatment, this article makes an attempt to refresh our knowledge on retainers by exploring the literature.
In Orthodontics the stability of the achieved result remains a fundamental issue of concern and debate. Tirk has said “The result of Orthodontic therapy - good, bad or indifferent is only evident many years out of retention”. Maintaining teeth in their corrected positions after Orthodontic treatment has been continuous to be the challenge . A phase of retention is normally required after active Orthodontic tooth movement to hold teeth in ideal aesthetic and functional relation and combat the inherent tendency of the teeth to return to their former position . Stability can only be achieved if the forces derived from the periodontal and gingival tissues, the orofacial soft tissues, the occlusal forces and post treatment facial growth and development are in equilibrium .
The most commonly used retainer designed in 1920’s as an active removable appliance. It incorporates clasps on molar teeth and a characteristic outer labial bow with adjustment loops, spanning from canine to canine. The outer bow provides excellent control of the incisors even if it is not adjusted to
retract them. When first premolars are extracted, one function of a retainer is to keep the extraction space closed, which the standard design cannot do. A common modification of the Hawley retainer for use in extraction cases is a bow soldered to the buccal section of Adam’s clasp on the first molars, so that the action of the bow helps hold the extraction site closed.
The wrap around or clip-on retainer, which consists of a plastic bar along labial and lingual surfaces of teeth. A full arch wrap around retainer should allow each tooth to move individually, stimulating reorganization of the periodontal ligament. In addition, a wraparound retainer, though quite aesthetic, is often less comfortable than a Hawley retainer and may not be effective in maintaining overbite correction. A full arch wrap around retainer is indicated primarily when periodontal breakdown requires splinting of teeth together.
These types of retainers can be made relatively quickly and by untrained personnel. The construction of the appliance is with the use of two 0.025” wires, which are bent and placed in the embrasure between the lower cuspid and lateral incisors and a separating medium is placed on the cast. The salt and pepper method are used to apply a quick- cure acrylic covering the labial surfaces from cuspid to cuspid and the lingual surfaces from first bicuspid to first bicuspid or second bicuspid if first bicuspids have been extracted. When the acrylic has set, retainer is removed from the cast, trimmed, pumiced and polished. The acrylic should be cut down on the labial to avoid being struck by the maxillary central incisors but left at the incisal edge on the lingual. The whole procedure requires about fifteen minutes
of working time and produces a smooth, inconspicuous, easily
fitted retainer that will do a positive job of controlling corrected
The lingual arch is formed of 0.045” hard SS wire. Adams
clasps are formed of 0.028 or 0.035” SS wire. Bend clasp tails
over arch wire so that stress is wire to wire and not on solder.
In soldering, use Hydro flame or electro soldering. Add buccal
wires, tubes, lingual finger springs, ball end clasps, and distal
extensions to second molars.
A tooth positioner can also be used as a removable retainer,
either fabricated for this purpose alone, or more commonly,
continued as a retainer after serving initially as a finishing
device. Positioners are excellent finishing devices and under
special circumstances can be used to an advantage as retainers.
For routine use, however, a positioner does not make a good
retainer. The major problems with positioners as retainer are as
i. The pattern of wear of a positioner does not match the
pattern usually desired for retainers. Because of its bulk,
patients often have difficulty in wearing full time or nearly
ii. Positioners do not retain incisor irregularities and
rotations as well as standard retainers. Also, overbite tends
to increase while a positioner is being worn.
The positioner has one advantage over a standard removable
or wrap around retainer - it maintains the occlusal relationships
as well as intra-arch tooth positioners. For a patient with a
tendency towards class III relapse, a positioner made with the
jaws rotated somewhat downward and backward may be useful
Essix thermoplastic copolyester retainers are a thinner, but
stronger, cuspid to cuspid version of the full arch, vacuum formed
devices. Essix retainers can be placed on the same day the fixed
appliances are removed. The vinyl polysiloxane impression is
taken immediately after debonding. Minor incisor rotations can
be corrected by altering the cast, since the teeth will be slightly
mobile. Seat the retainers over the incisors with firm finger
pressure. If a retainer will not seat properly, it is usually because
of internal plastic ridges formed by interproximal undercuts that
were not adequately reduced. These ridges can be smoothed out
at chair side with a scalpel. It is critical that the retainer does
not slip easily over the teeth but requires a reasonable amount
of pressure to flex over the interproximal undercuts gingival to
the Contact points.
They are normally used in situations where intra-arch
instability is anticipated and prolonged retention is planned,
especially the mandibular incisor area. There are mainly four
major indications, they include the following.
An excellent retainer to hold these teeth in alignment is a
fixed lingual bar, attached only to the canines and resting against
the flat surface of the lower incisors above the cingulum. This
prevents the incisors from moving lingually and is reasonably
effective in maintaining correction of rotations in the segment.
Fixed canine to canine retainers must be made from a wire heavy
enough to resist distortion over the long span between these
teeth. Usually 28 or 30 mil stainless steel is used for this purpose
with loop bend in the end of the wire to improve retention [7,8].
A second indication for a fixed retainer is a situation where
the teeth must be permanently or semi permanently bonded
together to maintain the closure of space between them. This
is encountered most commonly when a diastema between
maxillary central incisors has been closed. Even if frenectomy
has been done, there is a tendency for a small space to open up
between the upper central incisors. The best retainer for this
purpose is a bonded section of flexible wire. The wire should
be contoured so that it lies near the cingulum to keep it out of
occlusal contact. The object of the retainer is to hold the teeth
together while allowing some ability to move independently
during function. An alternative is a solid wire to avoid the tooth
contacts to facilitate flossing, which also can incorporate stops
to prevent deepening of the bite.
A fixed retainer is both more reliable and better tolerated
than a full time removable retainer and spaces reopen unless a
retainer is worn consistently . Bonded flexible wire lingual
retainer and the flexible spiral wire retainers were found to be
excellent in the following indication:
i. In midline diastema cases
ii. Spaced anterior teeth
iii. Adult cases with potential post orthodontic tooth
iv. Accelerated loss of maxillary incisors, requiring the
closure and retention of large anterior space.
A 4-4 Crozat appliance has cribs on the first bicuspids,
recurved double lapping lingual finger springs and a labial bow. It combines the advantages of other types of retainers and
has been well received by patients. Its advantages include the
i. Firm retention, because of the Crozat clasping
ii. Labiolingual control of anterior teeth to maintain or
restore arch form in the lower or upper arch
iii. Flexible, because it is all wire. It can be left out for
months and still fit
iv. Maintenance of adequate oral hygiene, because it is
v. Esthetic, because only a single labial wire shows.
The major disadvantages of the appliance are:
i. it must be fabricated at a quality laboratory, making it
cost prohibitive and
The molar to molar mandibular retainer is done with
the heavy gauge wire and with the use of molar bands. The
advantages of molar to molar mandibular retainer over a
Hawley’s or a cuspid to cuspid retainer include the following.
i. Allows the mandibular canines and molars to settle
ii. Mandibular arch can be expanded or contracted
iii. Rotations can be corrected by ligating the teeth to the
The Resin fiberglass bonded retainer was developed by
Michael. It is a direct technique that solves the major problem
with cuspid to cuspid retainer and takes 20 minutes or less with
previsit preparation. The system uses glass fiber from woven
fiberglass fabric or fiber bond. The main advantage of the resin
fiberglass retainer have proven rigid and impervious. Patients
appreciate the tooth colored material and the comfort that is
provided by smoothing the margins with rubber abrasive points
Retention is the important phase in orthodontic treatment
that is essential to achieve post treatment Stability and its
mandatory to plan the requirements of retention at the time of
diagnosis and treatment planning. Permanent retention is the
only way to ensure long term post treatment stability. However,
as trained orthodontist it is necessary to take a more pro-active
approach in dealing with the actions associated with relapse. We
should aim to remove the primary burden of preventing relapse
from our patients and would be well advised to maintain as
treatment goals the following well documented basic principles:
i. The patient’s pre-treatment lower arch form should
be maintained during orthodontic treatment as much as
ii. Original lower intercanine width should be maintained
as much as possible because of lower intercanine width is
the most predictable of all orthodontic relapse.
iii. Mandibular arch length decreases with time.
iv. The most stable position of the lower incisor is its
pretreatment position. Advancing the lower incisors is
unstable and should be considersd as seriously compromising
lower anterior post- treatment stability.
v. Fiberotomy is an effective means of reducing rotational
vi. Lower incisor reproximation shows long-term
improvements in post-treatment stability.