Finishing with lingual appliances /certified fixed orthodontic courses by Indian dental academy

FINISHING WITH
LINGUAL APPLIANCES

www.indiandentalacademy.com

INDIAN DENTAL ACADEMY
Leader in continuing dental education




When treating a malocclusion with the lingual
appliance, the finishing phase is probably the
most challenging and difficult stage of treatment.



A major advantage of the lingual appliance over
the labial appliance at this stage of treatment is
the absence of brackets, wires, and sometimes
gingival hypertrophy masking the labial surfaces
and possibly misleading clinical judgment.


 The

difficulties encountered at the
finishing phase of lingual orthodontics
derive from the following three main
sources:
 1. Patients’ characteristics
 2. Anatomy of the lingual surfaces
 3. Mechanics of lingual treatment


Patients’ Characteristics


Most of the patient receiving lingual orthodontics
are adults with specific personal requirements
often associated with general dental and
periodontal problem.



Treatment is more demanding and requires an
interdisciplinary approach with other dental
disciplines to achieve optimum final results.


 Restored teeth- full crown/lingual

restoration
–
–
–

Change in buccolingual thickness of tooth
Compensatory change in bracket base
Compensatory bends in initial wire


Abraded teeth





Vertical finishing is complicated by short
occlusogingival dimension and complexity of
lingual contour
Compensations for passive eruption
Extrusion/intrusion- Progressive 3D wire bending
is required


(A) Step-up bend to intrude
an incisor (a) will move the
crown labially as well. To
avoid the labial crown
movement, the step-up
should have an inset
component(b).
(B) Offset bend for labial
movement (c) will move the
crown gingivally as well. To
avoid the upward crown
movement, the offset bend
should have a downward
component (d)


Anatomy of the Lingual Surfaces




Modifications of the bracket base should
compensate for lingual anatomy including built in
tip, torque and in/out variation.
Accurate rebonding without alteration in original
bracket base


Mechanical Difficulties
Point of force application

Some distance from
labial surface which
defines final alignment

Some distance from
center of resistance

Hence finishing bends should be placed in more
than one planes of space

Short lingual arch length
Small interbracket distance

Poor expression of
prescription

Appliance should be left in position for longer time
with lower levels of force to prevent over powering
of appliance and archwire bowing


Side Effects Specific To Lingual Technique






Upright incisors
Mesially tipped molars
Lateral open bite (vertical bowing)
Arch expansion
Distolingual molar rotation (transverse bowing)


Prevention of Finishing Problems
 Correct patient selection
 Laboratory procedure

– Accurate bracket base construction
– Adequate bonding procedure- ↓ bracket failure
 Treatment mechanics (light forces)

– Avoid anchorage loss
– Avoid bowing effects
– Avoid torque loss

Minimize Wire Bending During Main
Treatment Phases




Correct bracket positioning
Full engagement of archwire
Complete prescription expression
– Vertical discrepancy may be due to incomplete torque
expression not bracket height


Rotational Correction


Difficult due to
–
–
–
–

Small arch perimeter
Reduced interbracket distance
Lack of space for overcorrection of bracket positioning
Less effective rotational bends


Mechanism of Rotation Correction




Full engagement of archwire
Reciprocal rotation
One by one rotation
– Bond the most severely rotated tooth first



Rotation off an anchorage unit
– Figure of 8 tie on multiple teeth to form anchorage unit


Mechanism of Rotation Correction


Rotation of a crimpable hook

– E- chain from bracket to hook crimped on archwire



Anti- rotation elastics

– Clear E- chain from bracket through contact point
along labial surface of rotated tooth and adjacent
tooth doubled back to hook on adjacent tooth



Rotation tie

– E- chain threaded on archwire before insertion



Half rotation tie

– Clear labial button is used

Systematic Finishing Procedure
O
B
S
E
R
V
A
T
I
O
N

General Facial & Dental Esthetics

Specific Tooth Positions

Step I of Finishing Protocol





Eliminate problems that derive from wire
disengagement
Allow expression of bracket prescription by using
resilient archwire
Incisor torque expression, minor rotation
correction, expansion
Vertical bowing effect correction


Step I of Finishing Protocol
(Mechanics)




Should be carried out for 3-4 months
17x17 Cu NiTi for 0.018 slot
Figure of 8 ligation across extraction spaces


Step II of Finishing Protocol





Settling of occlusion
Correction of minor midline discrepancy
Correction of minor anteroposterior & vertical
discrepancy
Mechanics
–
–
–
–

Lower stabilizing arch, 17X17 TMA or SS
Upper 0.014 round sectional SS canine to canine
Figure of 8 ligature
Vertical elastics

Vertical Elastics








Labial composite buttons are bonded
Anterior labial to labial – Class I & Class II cases
Anterior lingual to lingual – Open bite
Anterior upper lingual to lower labial - Class III
Anterior cross elastics – Center line discrepancy
Posterior vertical elastics
Period of wear 4-6 weeks


Step III of Finishing Protocol





Final detailing and finishing bends
Preferred over bracket repositioning
Done in pt time or on model
Mechanics
– Upper 17x17 TMA
– Lower 0.016 TMA



Bends are 1st placed in the maxillary archwire


Different Bends Used for Detailing
•Inset Bend
•Should be wide to avoid
adjacent bracket interference
•Accompanied by step up to
avoid elongation of crown


Different Bends Used for Detailing
•Offset Bend
•Should be narrow to allow
full engagement
•Accompanied by step down
to avoid crown shortening


Different Bends Used for
Detailing




Rotation bend
Should be tied with steel
ligature
Lingual component should be
away from bracket


Tooth Positioner



Suggested for final finishing
Risk of reopening extraction space and loss of
final detailing


Postfinishing Finalizing Procedures


After appliance removal– Occlusal contacts should be checked using
articulating paper
– Esthetic recontouring of incisal edges
– Bleaching of incisor edges


Thank you
Leader in continuing dental education


Finishing with lingual appliances /certified fixed orthodontic courses by Indian dental academy

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