iDentistry The Journal September-December 2017 | Page 20

*Dr. Amandeep Kaur Ahuja
**Dr. Sudhir Dole
***Dr. Sanket Kumar Baranwal
****Dr. Bhavdeep Singh Ahuja
The Journal
Retention and stability in Orthodontics : A review of the
literature
Maintaining the treatment result following orthodontic treatment is one of the most difficult aspects of
the entire treatment process. Normal maturational changes, together with post-treatment tooth
alterations, conspire against long-term stability. Long-term post treatment stability is an issue of great
concern to all orthodontists. This article highlights the factors reported to play a role in post treatment
crowding and reviews the long-term retention studies evaluating the stability of various treatment
modalities.
Mandibular incisor dimensions
Introduction
Retention may be defined as the holding of
teeth following orthodontic treatment in the
treated position for the period necessary for the
1
maintenance of the result .It is an important
factor in the success of any orthodontic
treatment. Teeth have the tendency to return to
their former position post orthodontic treatment,
which results in relapse. 2 In orthodontics the
long term stability of the achieved result
remains a fundamental issue of concern and
debate. Orthodontic retainers are specially
made devices, usually made of wires or clear
acrylic, that hold tooth in position after
orthodontics, orthognathic surgery or any
method of realigning teeth. They are most often
used after orthodontic correction to keep teeth
in position while allowing remodelling of the
surrounding tissue and to hold the teeth in ideal
aesthetic and functional relation and to prevent
the inherent tendency of the teeth to return to
3
their former position relapse .
Factors that affect post treatment stability
Although numerous factors have been reported
to play a role in post treatment crowding, no
definite conclusions regarding the relative
contribution of these factors have been
reached. Some areas of investigation are
discussed in the following section.
The mandibular incisors showed the most
rebound followed by the canines and then the
molars. The greater the proclination of
mandibular incisor during treatment, the greater
the irregularity. The conception that mandibular
incisor dimensions were correlated with lower
incisor crowding was reintroduced by Peck and
4
Peck after a study of 45 untreated normal
occlusions. They advocated reduction of
mandibular incisors to a given
faciolingual/mesiodistal ratio to increase
stability. Peck and Peck’s work, however, was
criticized because their recommendations were
based on a study involving untreated rather
than treated cases. Young patients with ideal
lower incisor alignment were used in the study.
It is possible that these cases would show
crowding if followed long term. To evaluate
more whether the Peck and Peck ratio had long-
term value, Gilmore and Little5 studied 134
treated and 30 control cases a minimum of 10
years post retention. They showed a weak
association between long-term irregularity and
either incisor width or the faciolingual/
mesiodistal ratio. In addition, the actual mean
difference in incisor widths between crowded
and uncrowded cases was only 0.25 mm.
These findings were also confirmed by other
studies(Keane, Smit, Alexander,Mills)6-
10which suggest that tooth structure plays only
a minor role (if any) in the etiology of late
mandibular incisor crowding.
* Orthodontist, Jalandhar
** Ozone Initiator and Private Practitioner, Mumbai
*** Private Practitioner, Bettiah, Bihar
**** Private Practitioner, Ludhiana, Punjab
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Vol. 13 No. 3
Sep-Dec 2017