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INDIAN DENTAL ACADEMY Leader in continuing dental education

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

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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 ď Ž

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

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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 

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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 ď Ž

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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 ď Ž ď Ž

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

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Finishing with lingual appliances  
Finishing with lingual appliances  

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