aao / aapd scottsdale 2018 missing premolars : what are ... · aao / aapd scottsdale 2018 missing...

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AAO / AAPD Scottsdale 2018

Missing Premolars : What are the Options?

• David Kennedy

• Clinical Professor UBC

• Vancouver Canada

• [email protected]

At what age can you know second premolars are absent?

• chronological age 8 to 9• compare to first premolar• compare to opposing arch• family history• late eruption

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Missing Second Premolars-Associated Anomalies

Infraocclusion – 25% vs 9%

Distoangular premolar – 8% vs 0.2%

Garib et al Angle Orthod 2009 : 79 : 436-41

Should we save or extract the E?

• Naoumova J et al J World Fed Ortho (2017) 6:142-6

• Systematic Review

• Outcomes of preserving vs extract E when 5 missing in normal occlusion

• No evidence to support either extraction or preservation

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Missing PremolarsTreatment Options

• Leave primary molars + build up +disk

• Extract – hold space – restore

• Extract – close space

• Extract early – drift – close

• Transplant

• Decoronation

• TADS to protract molars

4 PrinciplesKennedy DB Eur Arch Ped Dent 2009 10 : 201-10

• Establish correct space

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• Establish correct space• Preserve occlusal table


• Establish correct space• Preserve occlusal table• Preserve alveolar ridge

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• Establish correct space• Preserve occlusal table• Preserve alveolar ridge• Correct incisor position

3 Questions

• What would you do if the absent tooth were present?

• Can this malocclusion be satisfactorily treated with extractions?

• What is the likelihood of survival of deciduous molar?

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What is the survival rate of deciduous second molar with absent premolar?

What is the survival rate of deciduous second molar with absent premolar ?

• reduced numbers of retained maxillary deciduous molars

• mandibular molars maybe more durable

• mandibular molars show increased infraocclusion

• resorption occurs in about 50%

• sample bias ?

Sletten et al AJODO 2004 : 124 : 625-630

Rune & Sarnas Eur J. Ortho 1984 : 6 : 123-131

Bjerklin K and Bennett J Eur J. Ortho 2000 : 22 : 245-255

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• age 36 to 48 years

• negligible root resorption

• no infraocclusion

Sletten et al AJODO 2004 : 124 : 625-630


• If deciduous molar lasts to adulthood without resorption or infraocclusion : excellent prognosis for longevity.

Bjerklin K and Bennett J Eur J. Ortho 2000 : 22 : 245-255

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• deciduous molar wider than absent premolar

• results in end on / ½ cusp Class ΙΙ molar

Retained Second Deciduous MolarProblems : size of molar

• resorption progressive

• reduced crown root ratio for restoration

Retained Second Deciduous MolarProblems : root resorption

Before After

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• When ankylosed E is left

• non restorable

• space too wide

• end on molar

• surgical removal

• compromised bone for implant

• impact magnified with growth

• early ankylosis worse than late

• infraocclusion worse when absent premolar than if premolar present

Retained Second Deciduous Molar

Problems : infraocclusion

Kurol 1981 Comm Dent Oral Epid 9- 94

Kurol 1984 Eur J Ortho 6: 277-93

Kurol 1984 Angle Orthod 54 :283-94

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• infraocclusion magnified with growth

• space loss > leeway space

• adjacent teeth tipping

• reduced vertical growth of adjacent teeth

• midline deflection in unilateral cases

Retained Second Deciduous Molar

Problems : infraocclusion

Becker A et al AJO 1992 102 256-264



After Before

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When baby teeth behave badly – thanks Dr. Lesley Williams

Impact of Extraction of Infraoccluded Deciduous Molars - vertical

• don’t let infraocclusion extend beyond proximal contact - non restorable

Before ext After ext

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Can we enhance extraction socket for future implant ?

• Random Clinical Trial of coral granules placed in primary molar extraction sites

• Posterior Mx and Mn 93.5 % successful in preserving alveolar width

• No pre- implant grafting needed

• Socket preservation

Sandor et al : Dent Traumat : 19 : 221-7 : 2003

Missing Teeth Treatment

• Costs to replace missing teeth– orthodontic treatment

– prosthetic replacement

– adjunctive procedures

( CBCT / grafting )

– maintenance of prosthesis

– $ 5000 per tooth

– competes with college funds / availablity

– space closure eliminates these

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Treatment Options





• Transplant

• Decoronation


Missing Lower Second

Premolars Class 1 non

crowded

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Before

After

• interproximal reduction of mandibular second deciduous molars

• limited by root proximity / pulp size

• occlusal build up

Before After

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Before After

Leave upper space to obtain Class I canine and molar

Final Post restorative

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Treatment Options





• Transplant

• Decoronation

• TADs to protract molars

Missing Lower Second

Premolars –Class 1 minimal

crowding

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• Can the malocclusion be satisfactorily treated with extractions or not?

• What is the longevity of the deciduous second molar?

• extract lower primary molars / lingual arch

• non extraction treatment to open space for lower second premolar replacements

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Impact of Extraction of Infraoccluded Deciduous Molars – ridge width

• 25% of buccal lingual reduction occurs in first 3 years

• 4% more loss over next 4 years

• limited vertical change

• adequate bone for implant

Ostler & Kokich J. Prosth. Dent. 1996

Ridge changes with missing lower second premolars

Final

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• early extraction preserved bone height

• eruption of teeth brings bone with them

After Before

Ostler & Kokich J. Prosth. Dent. 1996

• Other anomalies

• late 1 . 7

• absent 3rd molars

• absent 3.5 4.5

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Implant supported crowns-after growth finished

6 years

after

implant

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Before After 3 unit bridge

• Maryland bridge until growth complete

• less invasive

• less cost

• future implant still an option

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Treatment Options

• Leave primary molars + build up + disk




• Transplant

• Decoronation


Class I mild crowding :

missing lower left second premolar

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• extract all second premolars

• slightly protrusive incisors

• steep mandibular plane

• encourages mesial drift of molars

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Final

Note mesial drift of molars, increased space

for third molar eruption, no impact on profile

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Treatment Options


• Extract – hold space – restore• Extract – close space• Extract early – drift – close• Transplant• Decoronation • TADS to protract molars

Initial - Missing Lower Second PremolarsTSALD 7 mm lower5 mm upper

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Extract Upper 4 and Lower E

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Post Ext 4 / E / Drift

Progress – Post Ext / Drift

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Progress – Post Ext / Drift

Final

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Static Working Non working

Final

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More room for 8’s –molars come forward

Final

Final

Post DriftInitial

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Missing

maxillary right second premolar

Class 1 crowded




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• Modified serial extraction• Place Nance – control molar / midline• Phase 2 with maxillary expansion and

fixed appliances

Post

Driftodontics

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Post Drift

Initial

Initial

Post Drift

Post Drift

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After drift Before ext

FinalThanks

Dr Flanagan

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Initial

Final Final

Initial

Missing Lower

Second Premolars

Class 2 crowded

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Treatment Plan

• full treatment

• skeletal camouflage (Class II)

• extraction of upper first permanent first premolars and lower second premolars

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Extract lower E / Drift

Post

Lower E

Extraction

and Drift

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• midline correction due to extraction timing

• Mesial drift of lower 6 with Minimal incisor retraction

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Before After

• Mesial drift improves Class 2 molar

Initial

Post Drift

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• Tipping at lower extraction sites

Before ext After ext / drift

Phase 2-extract upper 4-critical anchorage

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Final

• Mesial drift improves Class 2 molar

• Upper molar held in position

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10 years

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Rob Mintenko

3rd Year Resident-UBC

MSc Craniofacial Sciences/Diploma in Orthodontics

Dental Changes Following Serial Extraction of Mandibular

Second Premolars

Methodology• Two principal measurement methods:

– 1) Change in tooth angulation using lateral cephalometric radiographs

Yoshihara 2000

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Results – Dental Tipping• T0 = white

• T1 = blue

• T2 = red

-6.0⁰ +13.5⁰ +7.3⁰ +1.2⁰T0 →T1

T1 →T2 +10.1⁰ -13.8⁰ -8.3⁰ -3.0⁰

Palatal Plane

+ change indicates distal tipping of teeth

- change indicates mesial tipping of teeth

Group 1: Early extraction of lower 5’s

Teeth: Mandibular First Molar

Mandibular First Premolar

Mandibular Canine

Mandibular Central Incisor

Methodology

• Two principal measurement methods:

– 2) Changes in occlusal curves• Digitize plaster models

• Placement of points on digitized models

• Analysis via spheres

Curve of Spee Curve of Wilson Monson’s Sphere

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Results – Occlusal Curves

20.0

22.0

24.0

26.0

28.0

30.0

32.0

34.0

Curve of Spee Curve of Spee Curve of Spee

T0 T1 T2

Sp

her

e R

adii

(mm

)

Curve of Spee from T0-T1-T2

Group 1: Early ext 5's Group 2: Early ext E's Group 3: Late ext 5's Group 4: Control


48.0

50.0

52.0

54.0

56.0

58.0

60.0

62.0

64.0

66.0

Curve of Wilson Curve of Wilson Curve of Wilson

T0 T1 T2

SP

her

eR

adii

(mm

)

Curve of Wilson from T0-T1-T2


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42.0

44.0

46.0

48.0

50.0

52.0

54.0

56.0

58.0

60.0

Monson's Sphere Monson's Sphere Monson's Sphere

T0 T1 T2

SP

her

eR

adii

(mm

)

Monson's sphere from T0-T1-T2


Treatment Options





• Transplant

• Decoronation


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Missing all second premolars

Class 1 minimal crowding

Extract all second primary molars / driftodontics

• What would you do if the absent tooth were present?• Can the malocclusion be satisfactorily treated with

extractions or not?• What is the longevity of the deciduous second molar?

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Post E

Extraction

5 years

of Drift

After Before

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• Mesial drift of 6 with Minimal incisor retraction

Final

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Early extraction results in mesial drift of posterior teeth.

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Spontaneous Space Closure after Extraction

• 11 patients mean age 11.8 years

• Class Ι non crowded with missing second premolars

• models before , 1, 2 and 4 years

• ceph before , 2 and 4 years

Mamopouloua A et al E.J.O. 1996 : 18 : 589-600

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• 55% Mx space closed in 1st year

• 46% Mn space closed in 1st year

• at year 4 - 89% of Mx space closed : 0.9 mm left

• at year 4 - 80% of Mn space closed : 2.0 mm left


Lindqvist B E.J.O. 1980 : 2 : 173-181


• Mx premolar tipped 7º by year 4

• Mx molar tipped 4.5º by year 4

• Mn premolar tipped 9º by year 4

• Mn molar tipped 5.7º by year 4

• most tipping occurred in 1st year


Lindqvist B E.J.O. 1980 : 2 : 173-181

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• minimal incisor movement

• Mx incisor retroclined 3.5º

• Mn incisor retroclined 3.0º

• Mn incisors 0.9 mm posterior to A-Pg line

• unilateral case showed midline shift


Lindqvist B E.J.O. 1980 : 2 : 173-181

Treatment Options



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Premolar to Premolar TransplantClass II Camouflage Tx / Missing Premolar

Initial

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Post TransplantPost Transplant

Donor Pre Transplant

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Final

• working occlusion

• non working occlusion

• static occlusion

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Donor tooth

Final

Donor tooth Immediate post transplantDonor tooth

FinalDuring orthodontics

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Initial

Final

Treatment Options


• Extract – hold space – restore• Extract – close space• Extract early – drift – close• Transplant• Decoronation• TADS to protract molars

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Decoronation

• Preserve vertical bone

• Preserve buccal lingual bone

• Must be done before growth spurt

• No research available yet on primary molars

a Proffit WR, Fields HW, Larson BE, Sarver DM. Contemporary Orthodontics, Chapter 12,

6th Edition, Elsevier, Philadelphia PA, USA.

Treatment Options



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Initial

Initial

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Initial - Extract Upper 4 Lower E

Progress

Buccal and Lingual sliding mechanics for lower space

closure

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Indirect anchorageLace 3 and 4 to TAD

Buccal and Lingual sliding mechanics

for lower arch space closure

Final

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Final

Final

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Missing Premolars :What are the Options ?

• Longevity of primary molar• Leave primary molars + build up +

disk• Extract – hold space – restore• Extract – close space• Extract early – drift – close• Transplant• Decoronation • TADS to protract molars

Thank You

aao / aapd scottsdale 2018 missing premolars : what are ... · aao / aapd scottsdale 2018 missing...

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