Roth's Prescription / orthodontic courses by Indian dental academy

The Roth Prescription

The Roth Rx Dr. Punit Thawani

Functional Occlusion

• Increasing awareness and fear

• Roth’s interests– Belief that functional dynamics of occlusion imp. for

stability– To prove that no harm was being done to his pts. – To disprove that PM extractions could cause TMD



• Equilibration –

– Time consuming and difficult

– Only possible if there are minor problems

– Jaws had to have stable relation – i.e.. after growth.

– More important to straighten teeth better.



• SIX KEYS of Occlusion, with the mandible in CENTRIC RELATION



• The condyles should be seated superior and anterior in the fossae against the articular disks and the distal slope of the articular eminence, and centered transversely.

» Electromyographic study by Williamson



• Incisors in Class I occlusion• 4 mm overbite• 2-3mm overjet at incisors• 1mm overjet at canines• U Canine cusp tip below occl. plane – at level of

contact point b/w L3 & 4/5• U canine, slightly mesial axial incliation, so that it

touches disto – incisal slope of L canine



• Signs that mand. is not in centric – – Occlusal wear– Excessive tooth mobility– TMJ sounds– Limitation of mouth opening– Myofacial pain– Tightness of mandibular musculature



• Important to diagnose a patient from centric• Guide mandible into centric, and check for first

tooth contact– Articulator mounting may be necessary.– Splint therapy may be needed.



• Once mandible is stabilized in centric, Rx planning can begin.

• If large difference, ceph should be taken in centric, or adjusted accodingly.

• Jarabak ceph analysis and Ricketts VTO



Anatomic articulator mounting/SAM articulator



CO

CR

CR after equilibration of cast



Repositioning of the mandible on the tracing


Gnathological Objectives

3 parts –

1. On normal closure in centric relation

2. Protrusive movement

3. Lateral movement


Gnathological Objectives

On closure in centric• Class I occlusion at centric• Simultaneous contact of all posterior teeth with

force directed down the long axis of the posterior teeth

• 0.005” clearance of anteriors

CO = CR


Gnathological ObjectivesProtrusive movement.• Anteriors must gently

disocclude postriors• Sufficient overjet and bite • Occlusion – U 6 ant with L

ant and 1st PM– 14 teeth bear the stress

Mutually protected occlusion


Gnathological ObjectivesOn lateral excursions• Cuspids main guiding

inclines• U canine cusp tips ride

on disto-incisal incline of L canine.

• All other teeth lifted out of occlusion

Cuspid Guidance



• Too many brackets in Andrews’ prescription

• Translation – friction

• Roth did not translate teeth

• Overcorrection

• Wanted 1 prescription for all his patients.



• 5o more torque in upper incisors,

• Less torque in upper canines

• 2o more tip in canines

• 2o anti-rotation in canines and PMs

• Upright posterior segments

• Over-correction of U molar offset and torque



• Lower posteriors –

– 3o distal tip

– Distal rotation



Also available –

• Molar tubes with no upper molar offset

• “Super torque” anterior brackets

• Canines with 0o tip



Tooth II molar I Molar II PM I PM Canine Lateral Central

Maxillary 5/-9(14o

offset)

5/-9 (14o

offset)

2/-7 2/-7 11/-7 9/8 5/12

Mand. 2/-354o offset

2/-354o offset

2/-22 2/-17 5/-11 2/-1 2/-1



Bracket placement – as advocated by Andrews –

except –

• Upper anteriors and lower incisors bonded more

incisally

• Lower canines bonded slightly more gingivally



Archform – Tru Arch• Flatter anteriorly• Sharp curve in Canine PM

region• Gentle curve at post. legs.



Roth Andrews



Large amount of overcorrection because –

1. Brackets do not express themselves – play

2. Before complete expression – force levels drop

3. Tendency of teeth to relapse


Roth’s treatment mechanics


Treatment Objectives

1. Correction of Crossbites

2. Correction of jaw relations

3. Eliminate severe crowding

4. Create space in the arch for severely malposed/impaced teeth

5. Alignment of teeth in the individual arches


Treatment Objectives

6. Begin space closure

7. Finish the lower arch

8. Achieve class I relationship of the buccal segments

9. Retract and intrude maxillary anterior teeth.

10. finishing and detailing


Treatment Mechanics

3 phases –

1. Unlocking phase

2. Working phase

3. Finishing phase


Unlocking Phase

• Major corrections– Cross bites

– Severely malposed teeth

• Use of RME, Quadhelix, Bimetric arches, Utility arches

• Jarabak style loops in light wire

• Braided wires


Unlocking Phase

Jarabak light wire loops


Unlocking Phase

Main objective –

• Gross corrections

• Aligment with flexible wires – so that heavier

wires can be used later


Working phase

• Closure of extraction site• Correct a-p jaw relation and

dental relation• Intrusion, if required

• Space closure with double keyhole loop– Usu – 19x26 mil rounded edge

rectangular wire


Working phase

Double keyhole loop – • Space closure with 1 wire• Medium between tipping and translation• Permit either ant. retraction or post. protraction• Control of canine rotation• Used as elastic hooks.


Working phase

• Asher face bow for retracting anteriors en masse. – 12 – 15 oz of force for upper ant.


Working phase


Working phase

• Upper wire with gable bend distal to canine and COS

• To protract posteriors – cinch back keyhole loops – discontinue Headgear


Working phase

• Some tipping occurs after space closure – – 18x25 blue Elgiloy - COS

• 0.018 steel• 16 x 22 yellow Elgiloy 2 ½ turn helix


Working phase


Working phase

• After uprighting – – 21 x 25 ss wire with only archform and no COS– Occationally 22 x 28 ss wire


Working phase

• High angle cases – – Avoid heavy wires – max use of Nitinol and TMA and

braided wires

– Space closure on 0.016” SS wire

– Uprighting with 19x25 TMA/Nitinol/braided wire


Working phase

• Bimax cases – – Initial space closure with 0.018” or 0.020” wire with

double keyhole loops

– Once teeth are upright – intrude with Utility arch

– Continue space closure with 19x26 double keyhole loops and Asher face bow


Working phase

• Maximum retraction and torque control

– 21 x 25 SS or Elgiloy double keyhole loops

– Maximum torque control

– Reduce posterior ends


Finishing Phase

• Place full sized wires and let brackets express• Drop to braided – settling elastics

– Short Class IIs - minimum extrusion.?


Case report – Bimax.


Pretreatment


Retraction


After Space Closure


Post Treatment


Anchorage considerations

Factors that result in mesial migration of molars – • Heavy wires for leveling COS• Attempts to gain rapid alignment with heavy

wires• Uprighting distally tipped canines• Lingual root torque of max. incisors• Arch expansion with labial archwire• Retracting extremely procumbent anterior teeth



• Procumbent teeth offer a lot of anchorage• Once teeth are upright, they retract easily.

• Space closure can be done on any wire, as long as it is done slowly.



• Initial alignment on light wires – – 0.015 Coaxial wire then 0.017/0.019 Coaxial wire– Heavier wires (esp with COS – tend to procline teeth)

• For leveling COS – where do incisors need to be?– Intrusion with - 19 square Utility arch

• Then go to continuous wire


Minimal use of HG

1. Leveling on light wires – usually Coaxial

2. If procumbent incisors – upright with HG

– 6-8 weeks with HG – then reciprocal space closure

3. Band 2nd molars from the beginning

4. Intrude the incisors to level the COS


Expansion with archwire


Expansion with the Quadhelix

• Quadhelix can be used to correct molar rotation

• Mild buccal expansion– Buccinator mechanism and buccal musculature

retract the 1st molars ----- ???

– Truncated cone effect - used in Crozat appliance


Minimal use of HG

0.015 Coaxial 0.019 Coaxial


Minimal use of HG

0.020 double keyhole loopsExtends up to 1st molar

19x26 double keyhole loops


Minimal use of HG

Deep COS by end of Space Closure19 x 19 Utility arch

Incisor intrusion – 3 months

Intrusion of canine1 month


Minimal use of HG

Braided wire for alignment

21x25 NiTi then SS


Upper arch

• Upper arch treatment slightly behind the lower

arch

• When lower arch is in 21 x 25 SS – and upper in

braided – start short Class II elastics

• Go to 21 x 25 SS in upper – continue elastics

• Settling with 21 x 25 braided wire.


• Mandible is in centric – importance to TMJ

• Incorporation of different mechanics

• Use of HG to anterior teeth for minimal amount

of time

• Light wires for initial alignment, to prevent

proclination of incisors


References

• Orthodontics – Current Principles and Techniques– Graber and Swain

• Orthodontics – Current Principles and Techniques– Graber and Vanarsdall

• The Straight-Wire Appliance - 17 Years Later– Roth – JCO Sep 1987

Roth's Prescription / orthodontic courses by Indian dental academy

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