roth's prescription / orthodontic courses by indian dental academy
TRANSCRIPT
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
The Roth Rx Dr. Punit Thawani
Functional Occlusion
• 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.
The Roth Rx Dr. Punit Thawani
Functional Occlusion
• SIX KEYS of Occlusion, with the mandible in CENTRIC RELATION
The Roth Rx Dr. Punit Thawani
Functional Occlusion
• 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
The Roth Rx Dr. Punit Thawani
Functional Occlusion
• 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
The Roth Rx Dr. Punit Thawani
Functional Occlusion
The Roth Rx Dr. Punit Thawani
Functional Occlusion
• Signs that mand. is not in centric – – Occlusal wear– Excessive tooth mobility– TMJ sounds– Limitation of mouth opening– Myofacial pain– Tightness of mandibular musculature
The Roth Rx Dr. Punit Thawani
Functional Occlusion
• 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.
The Roth Rx Dr. Punit Thawani
Functional Occlusion
• 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
The Roth Rx Dr. Punit Thawani
Functional Occlusion
Anatomic articulator mounting/SAM articulator
The Roth Rx Dr. Punit Thawani
Functional Occlusion
CO
CR
CR after equilibration of cast
The Roth Rx Dr. Punit Thawani
Functional Occlusion
Repositioning of the mandible on the tracing
The Roth Rx Dr. Punit Thawani
Gnathological Objectives
3 parts –
1. On normal closure in centric relation
2. Protrusive movement
3. Lateral movement
The Roth Rx Dr. Punit Thawani
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
The Roth Rx Dr. Punit Thawani
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
The Roth Rx Dr. Punit Thawani
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
The Roth Rx Dr. Punit Thawani
The Roth Prescription
• Too many brackets in Andrews’ prescription
• Translation – friction
• Roth did not translate teeth
• Overcorrection
• Wanted 1 prescription for all his patients.
The Roth Rx Dr. Punit Thawani
The Roth Prescription
• 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
The Roth Rx Dr. Punit Thawani
The Roth Prescription
• Lower posteriors –
– 3o distal tip
– Distal rotation
The Roth Rx Dr. Punit Thawani
The Roth Prescription
Also available –
• Molar tubes with no upper molar offset
• “Super torque” anterior brackets
• Canines with 0o tip
The Roth Rx Dr. Punit Thawani
The Roth Prescription
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
The Roth Rx Dr. Punit Thawani
The Roth Prescription
Bracket placement – as advocated by Andrews –
except –
• Upper anteriors and lower incisors bonded more
incisally
• Lower canines bonded slightly more gingivally
The Roth Rx Dr. Punit Thawani
The Roth Prescription
Archform – Tru Arch• Flatter anteriorly• Sharp curve in Canine PM
region• Gentle curve at post. legs.
The Roth Rx Dr. Punit Thawani
The Roth Prescription
Roth Andrews
The Roth Rx Dr. Punit Thawani
The Roth Prescription
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
The Roth Prescription
Roth’s treatment mechanics
The Roth Rx Dr. Punit Thawani
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
The Roth Rx Dr. Punit Thawani
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
The Roth Rx Dr. Punit Thawani
Treatment Mechanics
3 phases –
1. Unlocking phase
2. Working phase
3. Finishing phase
The Roth Rx Dr. Punit Thawani
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
The Roth Rx Dr. Punit Thawani
Unlocking Phase
Jarabak light wire loops
The Roth Rx Dr. Punit Thawani
Unlocking Phase
Main objective –
• Gross corrections
• Aligment with flexible wires – so that heavier
wires can be used later
The Roth Rx Dr. Punit Thawani
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
The Roth Rx Dr. Punit Thawani
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.
The Roth Rx Dr. Punit Thawani
Working phase
• Asher face bow for retracting anteriors en masse. – 12 – 15 oz of force for upper ant.
The Roth Rx Dr. Punit Thawani
Working phase
The Roth Rx Dr. Punit Thawani
Working phase
• Upper wire with gable bend distal to canine and COS
• To protract posteriors – cinch back keyhole loops – discontinue Headgear
The Roth Rx Dr. Punit Thawani
Working phase
• Some tipping occurs after space closure – – 18x25 blue Elgiloy - COS
• 0.018 steel• 16 x 22 yellow Elgiloy 2 ½ turn helix
The Roth Rx Dr. Punit Thawani
Working phase
The Roth Rx Dr. Punit Thawani
Working phase
• After uprighting – – 21 x 25 ss wire with only archform and no COS– Occationally 22 x 28 ss wire
The Roth Rx Dr. Punit Thawani
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
The Roth Rx Dr. Punit Thawani
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
The Roth Rx Dr. Punit Thawani
Working phase
• Maximum retraction and torque control
– 21 x 25 SS or Elgiloy double keyhole loops
– Maximum torque control
– Reduce posterior ends
The Roth Rx Dr. Punit Thawani
Finishing Phase
• Place full sized wires and let brackets express• Drop to braided – settling elastics
– Short Class IIs - minimum extrusion.?
The Roth Rx Dr. Punit Thawani
Case report – Bimax.
The Roth Rx Dr. Punit Thawani
Pretreatment
The Roth Rx Dr. Punit Thawani
Retraction
The Roth Rx Dr. Punit Thawani
After Space Closure
The Roth Rx Dr. Punit Thawani
Post Treatment
The Roth Rx Dr. Punit Thawani
Post Treatment
The Roth Rx Dr. Punit Thawani
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
The Roth Rx Dr. Punit Thawani
Anchorage considerations
• 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.
The Roth Rx Dr. Punit Thawani
Anchorage considerations
• 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
The Roth Rx Dr. Punit Thawani
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
The Roth Rx Dr. Punit Thawani
Expansion with archwire
The Roth Rx Dr. Punit Thawani
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
The Roth Rx Dr. Punit Thawani
Minimal use of HG
0.015 Coaxial 0.019 Coaxial
The Roth Rx Dr. Punit Thawani
Minimal use of HG
0.020 double keyhole loopsExtends up to 1st molar
19x26 double keyhole loops
The Roth Rx Dr. Punit Thawani
Minimal use of HG
Deep COS by end of Space Closure19 x 19 Utility arch
Incisor intrusion – 3 months
Intrusion of canine1 month
The Roth Rx Dr. Punit Thawani
Minimal use of HG
Braided wire for alignment
21x25 NiTi then SS
The Roth Rx Dr. Punit Thawani
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.
The Roth Rx Dr. Punit Thawani
• 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
The Roth Rx Dr. Punit Thawani
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