Modified TPA for Couple Force Systems
*Smruti Chandan Mohapatra,
Senior lecturer, Department of Orthodontics and Dentofacial Orthopedics,Hi-tech Dental College and
Modified TPA for Couple
Professor, Department of Orthodontics and Dentofacial Orthopedics, Meenakshi Ammal Dental College,
Professor and Head, Department of Orthodontics and Dentofacial Orthopedics, Meenakshi Ammal Dental
J Contemp Orthod 2020;4(4):
Senior Resident, Department of Public Health Dentistry, SCB Dental College and Hospital, Cuttack.
Source of Support:
Conflict of Interest:
Couple force is required for the correction of moderate to
Fabricate a removable TPA in 0.7mm stainless steel wire
severely rotated teeth.
Accurate bracket placement or wire
with its insertion from mesial end of the lingual sheath to
engagement in a rotated tooth is often compromised in the
distal end. (If fabricated with its insertion from distal side,
initial phase of the treatment.The shape of the upper premolar
then free end of the TPA cannot be extended toward
roots also augments the difficulty for de-rotation. Distal-in
rotation of a maxillary tooth arecomfortably corrected by
While fabricating TPA, bend the double back (which will
attaching a couple force from TPA to a lingual attachment on
be inserted inside the lingual sheath) with its free end
the rotated tooth. But for mesial in rotation of a maxillary
extending to the mesial side.
tooth requires mesial driving force from the lingual side,
Then adapt the wire according to the lingual contours of the
which when delivered form the anterior teeth results in its
Hence, a modified removable TPA offers
The wire can be extended till the canine or lateral incisor
a simple,safe, less time consuming and economical solution.
depending upon the purpose of the treatment procedure.
This modification can be helpful in several other aspects of
At the free end, make a helix or two helicesof
the treatmentprocedure which is discussed with case reports.
diameter adapting to the palatal contours.
Composite or acrylic can be placed onto the free end of the
wire to prevent soft tissue injury.
Place the removable TPA inserting from mesial side of the
lingual sheath with the help of a Weingart plier and secure
it with ligature wire.
To correct mesial-in rotation of premolar, engage E-chain
from the helix of the TPA to the lingual attachment on the
Case report 1:
Fig.1: Fabricated Modified TPA
Mesial-in rotation of first premolar was corrected with the help
Journal of Contemporary Orthodontics, Oct-Dec 2020; 4(4):39-40
Mohapatra et al
of modified TPA described above (Fig 2). In the left upper
Maxillary Incisor by Elastics in Mixed Dentition
quadrant the premolar was successfully rotated and mesialised
Complicated by a Mesiodens. Int J ClinPediatr Dent
using the traction from the helix to create space for the
ectopically placed transposed canine. The un-favorable root
positions of the canine and premolar made it difficult to
mesialise the canine.
Case report 2:
Right upper first premolar was moved mesially with the help
of modified TPA described above
3). E-chain was
engaged to helix of the modified TPA to the lingual
attachment on the right upper first premolar. This generated a
couple force for mesialisation of the premolar preventing its
Fig.2: Intraoral occlusal view of before and after correction of Case
ig.3: Intraoral occlusal view of before and after correction of Case
The modified TPA has proven to be an easy and quick method
for the management of mesial-in rotation of premolars with
flat root configuration eliminating the need for complicated
Shastri D, Tandon P, Singh GP, Singh A. A New
Rotation Correction Technique: Technique clinic. J
Sidiq M, Yousuf A, Bhat M, Sharma R, Bhargava
N, Ganta S. Correction of a Severely Rotated