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Anchorage types
Science
ClinicalAP problemsCaninesMolars
Vertical problemsAOB
What’s being done?
TADs - What we really know
ANCHORAGE IN UK ORTHODONTICS
Routine HG use - 38%
Never use HG - 20%
Other methods:
Trans palatal arch 25%, Nance 20%
Implants 0.2%, TADs 65%,
Palatal implants 13%,
SALESMEN PROMISES ON TADSSmart, patient friendly . . . safe, secure . . . easy, intuitive, effective?
Annie C 126 Horizontal problem
JCC with restorative dentists from CCDH
Time for anchorage supplementation
Class 1 canines
Implantologists requirements?
11
Annie C 186
Charlotte 156, Vertical problems
Contact only on second molars
Time for extraction decision…
X X
2mm overbite finally!
Overcorrect molars - 30% relapse risk reported!
Treatment time28 months
Lisa 28
XXX
X
Modified arch toallow intrusion
Added hooks give options
Power chain applied on buccal & palatal
Horizontal issuesOlivia - 149
Referred by GDP for extraction of 47!
Major risk of over-retracting LLS
Overjet is still only 2.5mm, OB hasn’t ⬆d
All lower space closed, LLS looks good
8s have kept up with the mesialised 7s
Theresa 166 - uprighting 7s
Horizontal and vertical problem . . .
Horizontally impacted LR7, slight mesial impaction LL7
X X
Mesial marginal ridge of LR7 now visible
26 months of conventional orthodontics
Natalie - 166
1
11
12 2
8mm in total - for two lateral incisor pontics!
More horizontal problems
Treatment time - 18 months
Updated 2011 - Safa, Sandler et al
What about the science?
TADS - WHAT WE REALLY KNOW•Simple to place and remove
•Well tolerated
•Low failure rate < 20%
•Inexpensive
•Minimal co-operation required
•Some evidence demonstrating they work better than HG or palatal arches
What else is being done?
Science in Cyprus
TADs literature review
Design of the study
Anchorage loss measurement
ResultsMolar movementProcessPatient views
Conclusions
TADs literature review
Design of the study
Stability of the rugae
ResultsMolar movementProcessPatient views
Conclusions
3364 abstracts
3312 excluded
General Selection Criteria
success of mini-implants measured
human studies, > 10 screws
ignored technique articles, case reports, opinion pieces, reviews, lab studies, animal
studies, in-vitro . . .
implant diameter < 2.5mm
excluded mini-plates
52 scrutinisedFurther 21 excluded
General Selection Criteria
success of mini-implants measured
human studies, > 10 screws
ignored technique articles, case reports, opinion pieces, reviews, lab studies, animal
studies, in-vitro . . .
31 dissected
Further 12 excluded
19!
Specific Selection Criteria
only if they specifically defined success
only if they defined force duration
only if they measured success @ > 3/12
only if they pre-defined time to measure success or measured @ Tx completion
Assessment of validity clear in only 3
Fewer than 50% wereprospective studies
Conclusion: Poor methodology and lack of clarity generally Clinical studies considered in their infancy More RCTs - standardized methodology proposed
4115 abstracts
4063 excluded
Reasons for exclusion explained
52 included infailure estimate
Only 30 in risk factor estimate
CONCLUSIONSRisk Factors
• 4987 miniscrews in 2281 patients - failure rate 13.5% (95% CI 11.5-15.8)
• No association with sex, age, insertion site (BL vs PL), thread morphology
• Jaw of insertion was important: failure in mandible (19%) maxilla (12%)
Exploratory analyses (< 5 studies)
• Self drilling vs no drilling & immediate loading vs late loading - no difference
• No association with cortical notching or type of soft tissue
• Root contact results in 30% failures - absence of root contact - 8% failures
Examined all randomised and quasi-randomised studies
Only Benson et al (2007) of ‘Cochrane’ quality for scientific assessment of surgically assisted anchorage
Conclusion: Quality of almost all the studies pre-2007 was lowLimited evidence suggests palatal implants support anchorageMore RCTs are required
. . . the Cochrane Collaboration policy is reviews updated every
two years or include a commentary why not . . .
Update of the Cochrane review - surgical anchorage
Safa Jamba was the lead researcher
Contacted CCDH - offered to do r/v
Reviews need 2 reviewers
PJS - co-researcher
K.D.O’B the adjudicator
108 reports identified by initial search
!
!
!
!
!
!
25 abstracts remained
Study eligibility form
11 reports included3 unclear, authors contacted ultimately
excluded
11 excluded
7 reports finally included
Title and abstract scanned
Duplicates identified
!
ONLY 4 STUDIEDMOLAR MOVEMENT
MOLAR MOVEMENT STUDIES
Study InterventionInterventionInterventionIntervention
Chesterfield HeadgearHeadgear Palatal implantsPalatal implants
Upadhyay 1 HeadgearHeadgear TADsTADs
Upadhyay 2 ConventionalConventional TADsTADs
Feldmann HG Palatal arch Onplant Palatal
implants
RESULTS
StudySurgical
NMean Conventional
NMean Mean
differenceMean
differenceMean
difference
Chesterfield 23 1.5 24 3 -1.5
Feldmann 54 -0.1 59 1.5 -1.7
Upadhyay 1 18 0.7 18 3.2 -2.4
Upadhyay 2 15 0.8 15 2.0 -1.2
Total 110 116 -1.75
Favours surgical anchorage
Favours conventional
• Many papers have been written on TADs since 1983
• Very few would stand scientific scrutiny
• Seven scientifically sound RCTs have been published on anchorage
• Four demonstrate surgically assisted anchorage superior to conventional anchorage, for maintaining molar position (226 pts)
• Further high quality RCTs desirable
THE BOTTOM LINE
. . . time for another RCT
Any difference in anchorage supplementation capability
. . . in maximum anchorage cases . . . treated with
Headgear Nance TADs?
WHAT DID I ASK?
!!
v v
. . . and what was the ‘process’ of treatment?
• Based on clinically meaningful difference in anchorage loss of 1.5mm
• Common SD 3.03 (Luecke and Johnston, AJODO 1992)
• Power 80%, alpha 0.05
• Non-compliance 20% (Sandler et al. AJODO2008) . . . therefore 25 patients per group needed nQuery Advisor statistical software
Sample Size Calculation
Maximum anchorage cases - no forward movement of upper molars allowed
Give patients ownership of the decisions
WHAT DID I DO?
78 patients
!
!
10m, 15f 19m, 7f 10m, 17f
2f discontinued 2f & 3m discontinued
22 analysed26 analysed23 analysed
14.38(1.67) 14.14(1.48) 14.15(1.25)
90 patients12 declined
WHAT DID I DO?
78 patients
!!
10m, 15f 19m, 7f10m, 17f
22 analysed26 analysed23 analysed
14.38(1.67) 14.14(1.48) 14.15(1.25)
90 patients
12 declined
Didn’t want: orthodontics - 1, to be in a study - 4 Nance - 3, HG - 3, TADs - 1
WHAT DID I DO?
78 patients
!
!
10m, 15f 19m, 7f 10m, 17f
2f discontinued 2f & 3m discontinued
22 analysed26 analysed23 analysed
14.38(1.67) 14.14(1.48) 14.15(1.25)
90 patients12 declined
WHAT DID I DO?
78 patients
!
!
10m, 15f 19m, 7f 10m, 17f
2f discontinued
2f & 3m discontinued
22 analysed26 analysed23 analysed
14.38(1.67) 14.14(1.48) 14.15(1.25)
90 patients12 declined
Mesial molar movement measured on cephalogram
!
!
97
ANCHORAGE LOSS MEASURED BY:
!
!
!
!
!
!
ANCHORAGE LOSS MEASURED ON
DIGITAL MODELS
!!
Iterative Closest Point
= algorithm for superimposition of 3D objects
“Cross section” of upper model
TARGET
SOURCE
Identify correspondences
If overall ‘fit’ < 0.8mm deemed acceptable
then move to regional superimposition
101
6 degrees of freedom
TARGET
SOURCE
ITERATION 1- ROTATE
TARGET
SOURCE
ITERATION 2- TRANSLATE
ITERATION 3 - another rotation . . . etc.
ITERATION n - TRANSLATE
Iterative closest point - ‘least squares fit’
Initial molar shell used for both start of anchorage and end of anchorage ‘Centres of
Mass’
X Y Z
X: Bucco-Palatal Y: Vertical Movement
Z: Mesio-Distal movement of the post-treatment molar
Double determination demonstrated method as precise
Analysis of CovarianceRegression models for effects of treatment on outcomes
CRIME SCENE DO NOT CROSS
CRIME SCENE DO NOT CROSS
CRIME SCENE DO NOT CROSS
0.07
0.09
0.01
0.06
0.23
R2
Analysis of CovarianceRegression models for effects of treatment on outcomes
Right molar position, as measured on digital models
P = 0.05 therefore statistically significant
BUT Nance and TAD differences clinically small & CI cross zero
Therefore - no ‘overall effect of treatment’
R2
0.07
Analysis of CovarianceRegression models for effects of treatment on outcomes
Also no ‘overall effect of treatment’ on:Left Molar positionor . . . total treatment timeor . . . total number of visits
0.09
0.01
0.06
R2
Analysis of CovarianceRegression models for effects of treatment on outcomes
Statistically significant effect of treatment on the final PAR
TADs 4 PAR points better than headgear
. . . the only real difference so far!
Investigate process of treatment
R2
0.23
GroupDuration of anchorage
months
Total treatment time (months)
Number of visits Casuals DNA
13.01+5.7 28.01+5.4 19.2+6.4 1.88+1.8 1+1.8
15.9+2.9 27.43+6.3 21.8+4.4 1.81+2.0 1+1.3
9.0+4.2 26.8+9.3 18.3+5.9 1.78+1.7 1.2+2
What did I find about treatment process?
!
!
No real effect of Tx method on molar position
Another determinant of treatment method required
Process Placement discomfort
Discomfort level days 1-3
Number of discomfort days No Problems?
4.6+2.1 3.5+2.8 2.6+4.2
Removal discomfort
Discomfort level after 3 days
Number of discomfort days
Recommend to a friend
4.3+0.78 4.9+1.1 1.1+1.4
Levels of discomfort - 6-pt. Likert scale
!
!
4.3+1.1 3.7+1.6 3+2.1 17
4.3+1.4 4.8+1.5 1.1+1.4 20/22
20
24/26
V.s imi lar
levels
both highly
recommended
!
Free comments about Nance problems
food got stuck under arch
sometimes would catch roof of mouth
it felt like it was dislodged into the gums
little inflammation
concerned how to clean under it
catching skin on roof of mouth
!
Free comments about Nance after removal
it was comfortable when fitted
easy to get used to
not very painful and easy to get on with
good and comfortable treatment
very effective
no particular discomfort in removal, the area tickled and
was tender
Free comments about TADs
uncomfortable at first, but all worth while
didn’t know he had removed screw
after a couple of days of hurting, I couldn’t feel anything
microscrews pain free, tightening braces very painful
worked well, comfortable
tender for a bit after, but all ok 24hrs later
very impressive on how the screws work
Process Requested hrs Actual hrsReported months of
HGComfort
(1-5)
13.9+3.3 10.9+4 9.9+4.7 2.87+1.4
Convenience(1-5)
Social interference
(1-5)Did it bother
you? (1-5)Recommend to a friend
2.9+1.4 3.8+1.5 2.8+1.5 13/23
What did I find in the HG group
!
!
Free comments about HG problems
!
hard to sleep
pain sometimes
at beginning getting used to fitting in right slots
broke whilst on holiday, pain sometimes
uncomfortable at night when sleeping, also when putting in
left mark on hair
difficult to eat and drink, rubbed cheek
impracticle (sic)
hurt to lay down on pillow
Free comments about HG after removal
!
wouldn’t rec if alternative,
makes you very conscious
very happy with teeth afterwards
uncomfortable to sleep, but got used to it
got used to it but glad not to wear now
it works but embarrassing to wear
don’t understand how people can wear it,
even in sleep I would take it off
Few differences between techniques, in terms of molar position, as measured by superimposition of 3D models
Benson at al. (2007) and Feldmann and Bondemark (2008) both reported surgical anchorage better . . . they were using OSSEO INTEGRATED implants
Discussion
All previous studies based on cephalograms with all the inherent errors:
patient positioning errors
errors of projection
measurement errors
landmark identification errors
bilateral structures ‘averaged‘ on imprecise sketchings
Discussion
Being able to separate left and right molar movement adds a degree of precision
Discussion
TAD problemsone placement issueone became loose
one TAD fracturedtherefore 2.8% failure rate
No differences in terms of molar position
Best PAR scores in TADs cases
Discomfort levels similar with Nance and TADs
Nance and TADs both highly recommended
HG least recommended method
TADs - treatment of choice if absolute anchorage
Conclusions
