orthodontics In summary Farooq Ahmed
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- Education
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Farooq brings the key points, references and understandings from keynote webinars and papers in a concise podcast.
Providing easy access to gain the most from our esteemed speakers and experts.
*Important to note the information is from our interpretation as individual professionals, and may incorporate our opinions*
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Direct to Print Aligners, are they really different to normal aligners? 8 MINUTE SUMMARY Simon Graf
Join me for a summary
of direct to print aligners. This lecture explores the application of a relatively
new resin material which can be used for aligner fabrication, without the need
of a 3D printed model. The lecture was given by Simon Graf who expertly
compared the differences between conventional and direct to print aligners, as
well as the clinical application of specific features of direct to print
aligners.
Limitations of
current aligner material:
1.
Only small
undercuts
2.
Limited
aligner thickness to sheet thickness / no selective thickness
3.
During the
manufacturing process material can get thinner or thicker depending on heat distribution
and stretch, 54% change in thickness of the aligner Lee 2022
4.
Plastic
and resin waste, (122 million aligners and models in 2022 Slaymaker 2024)
Advantages of direct
to print aligners
· Select thickness, 0.5-0.7mm, conventional
aligners 0.75mm+
· Gingival margin
·
Dentist in
charge of design, not company
Manufacturing steps
of Direct to Print aligners (Tera Harz ‘Graphy’)
1.
3D printing
of resin aligner
2.
Centrifuge:
Spin remove excess resin
3.
UV Light
cure in Nitrogen chamber
4.
Washed
twice, hot distilled water
Characteristics of
Direct to print aligners
· Greater accuracy: (Zendura, Essix
Ace and DTP were compared and DTP were 20-30% more accurate Koenig 2022)
· Less with DTP (Hertan 2022)
o
DTP 50%
less still (2.59 Vs 5.26 N)
o
DTP Less
force as strain increases
Shape memory effect
· DTP Polymer chains crosslinked, not case in conventional aligners
o
The shape recovers in DTP when
strain is removed, which does not occur to the same degree in conventional aligners
Lee 2022
o
Accelerated by placing in water
Unknowns
· How effective shape memory is remains unclear
· Cytotoxicity – not enough data, although manufacturer
protocols, lack of studies
· Changing thickness, unclear how much of a
difference in force it makes
Clinical points
Teeth extrusion
Lateral incisors
· Difficult to do with conventional aligners,
· Create ‘wedging’ gingival pressure columns to
squeeze the teeth to cause an extrusive force.
Elastic Hooks
without loss of force delivery on single tooth
· Hook printed into aligner with DTP, instead of cut
out which alters the force of the aligner instantly, maintain tooth control
· Tip aligners and elastics: Still add attachment
to tooth to prevent aligner displacing
Mandibular advancement
· Problem of mandibular advancement with aligners
o
Wings soft
and not maintaining the AP position
o
Hard block
many breakages
· DTP choice of thickness of block
Bite ramps
Conventional bite
ramps: limited length and often too short
DTP no limit to size
and thickness, and can be designed to not contact upper palatal surfaces, maintaining
full tooth control
In the Transverse
o
Palatal
coverage can be added as feature, similar to a TPA
o
Still
being researched how much force can be delivered with palatal coverage
Concluding statement
Enjoy the variability
of direct printed aligners.
Contributions
Contents:
Abdallah Sharafeldin
Edited
and produced: Farooq Ahmed -
Think pink – orthodontics a problem or solution to gingival recession. 6 MINUTE SUMMARY
Join me for a summary looking at gingival recession in orthodontics, and whether it is detrimental or beneficial. This lecture was given by James Andrews, he explored the effect of orthodontics on the periodontium, an area under increasing interest within aesthetics to achieve the ideal ‘pink aesthetics’ with the increasing adult population receiving orthodontic treatment. His lecture was based on, is orthodontics good or bad for the gingiva?
What is the starting point ?
Increase in adult orthodontics from 1970 by 800%
50% of adults have some element of periodontal disease
Untreated adult population 51% dehiscence 37% areas of fenestration Evangelista 2010
Facial type and bone morphology Tunis 2021
Dolichocephalic = narrow alveolus and elongated to compensate for vertical growth
Brachycephalic = larger alveolus
Dolichocephalic - Red flag patients
Tooth movement:
What happens when teeth move buccally?
facial tooth movement Wennström 1996
Reduced bucco lingual width
Therefore, reduced free gingiva
Increased risk only if tooth is moved out of the alveolar housing
What type of movement
Tipping (uncontrolled) increase likelihood of recession Condo 2017
Proclination causes recession, but inconclusive
Thickness more relevant than final inclination Yared 2006
How to decide what to do?
WALA line – Will Andrews Larry Andrews ridge Andrews 2000
Limit of labial bone – shape is coincident with the mucogingival junction, coincident with centre of resistance
Upper incisors – located anterior 1/3 of alveolus
Mandibular incisors – cantered within the alveolus
Gingival recession did not increase in treatment orthodontic population with segmental mechanics Melsen 2005
Aligners any different?
Association between non-extraction clear aligner therapy and alveolar bone deficiency and fenestration
Presence of both fenestration and dehiscence
What do we do to correct extra-alveolar teeth?
If teeth pushed outside of cortical plate then retracted, what happens
Monkey – moved teeth outside of bone for 8 months, then reposition within bone with appliances = repair bony dehiscence and fenestration
Morten Laursen and Melsen 12 consecutive patients 2020
Teeth moved towards the centre of the cortical plate = improvement in gingival height of depth decrease of 23%, the width with 38%
Intrusion
Use of intrusion arch increases the thickness of the periodontal fibres 0.7 to 2.3 mm Melsen 1988
Gingival graft when to move teeth
Free gingival graft – 6 weeks
Connective tissue graft – 12 weeks
“Diagnose and treat each tooth no miracles shortcuts for good orthodontics” Peck 2017 -
TADs is success in science or practice?
Join me for a summary looking at miniscrews, looking at
where the answer to successful TAD placement lies, in research or clinical
practice. The reasons for higher failure rates than others with TADs was
explored through 3 key factors; insertion torque, site selection and root
proximity. Evaluation of both scientific and clinical processes were described
by Sebastian Baumgartel at the British Orthodontic Conference, as the
Northcroft lecture.
Is torque a factor in TAD success?
Torque study – compression during insertion Motoyoshi 2006
·
High torque – 60%
·
Low torque = 72%
·
Medium torque – 92%
Understanding
·
Low torque = low compression, low primary
stability - early failure as not engagement with screw
·
High torque = high compression, early success,
but greater resorption after insertion, remodelling results in a resorption
process
·
Medium = best of both = sufficient compression
for primary stability, not high enough to cause resorption remodelling
Ideal
·
Ideal torque range – 10 Ncm Shantavasinkal 2016
o
Study of buccal tads
·
Sebastian’s empirical experience between
10-25Ncm depending on site
Rules:
·
Aim for medium torque
·
Target 10Ncm
·
Exceed 10Ncm on palate acceptable
What is the best site for TAD insertion?
Keratinised gingiva
·
Evidence - states no difference Lim 2009, Chen 2008, Park 2006, Cheng 2004
·
Non Keratlised – depends on mobile or non
mobile, with non-mobile higher success rate Viwattanatipa 2009
·
2mm apical to muco-gingival junction
o zone
of opportunity
Target zones and site
o
No roots
o
Consistent cortical bone
o
More tolerant to higher torque
o
Attached gingiva with low mobile mucosa
Is there ideal bone?
·
= if
ideal torque = ideal cortical plate thickness
§
1-1.5mm cortical plate thickness
·
CBCT can be overkill, using research sites for
average sites
Ideal site:
–
1st premolar region (transverse)
Sebastian 2009
–
2 mm away from mid-palatal suture
o
= creates ideal zone ‘Mx1’
Evidence of site selection success
·
98% Vs buccal 71% Houfar 2017
·
84% Trainee success Sebastian 2020
·
Success of Sebastian anterior palate 100%, maxillary
buccal lowest 85%
Does root proximity influence TAD success?
·
Not just contact with roots, but proximity to
root also causes failure Kuroda 2007, Asschericks 2008, Chen 2008
Understanding
o
Increase root and PDL proximity = bone stress increases = increase bone turnover
= increase failure of TAD
·
4mm interradicular distance needed (depending on
size of tad) to achieve 1 mm clearance from roots
·
Most buccal sites have less than 4mm (resolve
through diverging roots, or sites with no roots)
What happens if TADs fail and we try again?
–
Secondary insertion success
o
58% (reduced by 33%) Park 2006
o
44.2% (reduced by 36%) Uesugi 2017
o
58.1% buccal (reduced by 21%), 88.9% palatal
(increased by 4%) Uesugi 2018
§
Uesugi 2018 showed buccal failure increases for
secondary insertion, but palatal insertion increases success
For more education see Sebastian’s TAD course:
https://tadchallenge.com/tad-certification-course
I have no financial interest
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Aligners: do patients wear them and do attachments really work?
Join me for a summary of Tommaso’s lecture on aligner treatment, exploring questions on the use of aligners. Tommaso described how compliant patients are with the use of aligners, who is more likely to wear aligners well and methods to increase compliance. He critically reviewed the use of attachments, and revealed aligner deformation and staging as key areas of treatment. This podcast is a summary of the WFO online webinar from November patient compliance, biomechanics , rotation, distalisation and intrusion
Patient Compliance
Sample of over 200 patients treated with aligners under remote monitoring, Thirumoorthy 2021:
36% of the sample was fully compliant
25% has poor compliance
1st time Ortho patients are more compliant
Conclusion: early detect non compliant patients with remote monitoring
Patient factors which vary compliance of removable appliances Fleming 2019
The study came with some recommendations:
Effective communication with our patients, with visual aid, pictures or movies.
Using of tracking sensor included in the device
Using some reminding tools – remote monitoring
Biomechanics and material properties.
Distalisation class 2
Incisors intrusion
Conclusion
We need to consider the lines of forces and aligner deformation not only on the attachments
Any malocclusion that can be corrected by tipping has better predictability
Add less activation Per aligner (to help flattening the steep decline in force over time and create consistent and continuous force system)
Attachment driven mechanics are not always effective, aligner Activation is more effective
Graphy is the trending technology in aligner activation -
Third permanent molars, what should orthodontists do?
Join me for a podcast summary looking at the grey topic of
lower third molar management. The podcast explores the different guidelines of removal,
factors for consideration for removal as well as the effect orthodontics can
have on third molar pathology. The lecture was given by Flavia Artese at this
year’s British Orthodontic Conference in my city London.
Flavia Artese began with asking the clincal question we
face, what would you do with an impacted 3rd molar?
Difference in international practice
·
UK NICE guidelines 2000: Surgical removal of
impacted third molars should be limited to patients with evidence of pathology
·
AAOMS White paper USA 2016: currently or likely
to be non-functional associated with disease or at a high risk of developing
disease
What factors in decision making
1.
Eruption path
·
Mandible = mesial, whereas Maxilla = distal
o
Rate of impaction Mandible 25%, maxilla 14%
Worthington 2016
2.
Mechanism of tooth eruption – explained by
Frazier-Bowers
·
A pathway created by the dental follicle
o
Triggers eruption of intraosseous eruption
o
Genetic control of cell differentiation in
dental follicle
§
Requires root elongation, vascular pressure and
DL ise 2008
Orthodontic influence
= SPACE
·
Decrease with distal movement of posterior teeth
o
Distalisation, elastics
§
Kim 2014 = limit of lower molar distalisation
§
35% of cases already have contact with lingual
cortical plate
·
Increase through mesial movement
o
80% of 3rd molars erupted in premolar
extraction cases Kim 2003
o
Increase in retromolar area
o
2nd molars – removal of guidance =
unpredictable alignment of 3rd molars, tipped, therefore will likely
require orthodontic alignment Gooris 1990
§
Flavia suggested if 7s impacted, removal of 8s
and 2nd molar uprighting, as no delay until full root development
Prediction method
·
Mandibular morphology
o
Longer the mandible = greater chance of 3rd
molar eruption: Begtrub 2012
·
Retromolar space
o
OPG -
size of crown and space available: If space greater then size of the
tooth = 75% eruption, if less space available than the tooth size = 75% of
impaction Olive
Prediction of orthodontists and surgeons Bastos 2016
·
Orthodontists 38% extract
·
Surgeons 50% extract
·
Surgeons extract more
o
Surgical morbidly 10% Yamada 2022
o
Greater pathology: 82% when erupted, 74% in soft
tissue, bone 33%
Surveillance protocol
·
No complaints from patients
Fully erupted
·
No consensus of protocol pathology
Review of guidelines Gadiwalla 2021
Only 2
guidelines were recommended , RCS and SIGN
·
Recommended guidelines
Conclusion
·
Limited evidence
·
Orthodontists can influence the space
·
If second molars require extraction, will
require time to erupt as well as
·
CBCT should be used for diagnosis
·
Refer to oral surgeon for assessment of
difficulty in removal
Please join Flavia Artese at the 2025 International
Orthodontic Conference in Rio De Janeiro
Contributions
Contents: AbdAllah Sharafeldin
Contents edited and
produced: Farooq Ahmed
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What are the limits of orthodontic movement?
Join me for a podcast exploring the limits of
orthodontic tooth movement. This podcast is a summary of two intriguing
lectures, by Dr Yanqi Yang and Carlos Flores Mir from this year’s International
Orthodontic Symposium by the IOF. This podcast explore the anatomical and
periodontal boundaries of orthodontic tooth movement
Anatomical boundary
·
Distalisation: Alveolar boundary lower
molar distalization
·
Horizontal: Atrophic ridge.
·
Vertical: Maxillary sinus
boundary for lower molar distalization.
o
Coronal level: Anterior border of
mandibular ramus
o
Apex level: lingual plate
o
Variable – distance from second
molar distal root and inner lingual cortex
§
Favourable Class 3 greater retromolar
space, class 2 least Fan 2022
§
Unfavourable High angle have
shorter distance Kim 2021, Victoria 2022
Side effects of lower molar distalisation
o
Mainly tipping
o
Distalisation achieved at apical
level approximately 1mm AJODO 2016
o
Lingual plate contact 1/3 of cases Kim
et al 2014
Horizontal movement: atrophic ridge
·
Change in width and height of
extraction site
o
Loss of 40-60% width and height
Pagni 2012
§
Width 3.79mm Tao 2012
§
Height 1.24mm Tao 2012
o
Mostly within 6 months Schrepp 2003
·
Changes when orthodontic tooth
movement into atrophic edentulous site
o
Increase bone height 2.2-5.2mm,
duration 24 months Elif 2004
o
Increase in width 0.8-1.6mm
Stokland 2011
o
Greater height increase buccally,
less lingually Dos Santos 2017
·
Side effects
o
Root resorption – lateral
§
0.7mm
o
Dehiscence
§
Slight in all cases, thinning of
alveolar bone Patricia dos Santos 2017
o
Reduced bone height compared to
non-edentious area
Vertical:
·
Maxillary sinus prevent tooth
movement?
o
Increased tipping, slower rate of tooth
movement
·
Side effects
o
Mild increase in RR
o
No difference in relapse, vitality
or periodontal differences
o
6 buccal roots closest . (Qin et al
2020)
·
Understanding
o
Maxillary sinus remodels itself
with tooth movement
o
Increase in resistance to tooth
movement, greater tipping.
Periodontal boundaries
Carlos Flores Mir started the topic with a thought proving
question, that we are well aware of Proffit’s envelope of lower incisor dental
movements; but the question of what
is the periodontal limit, is still yet to be clearly defined.
The difference between the gingival biotype and phylotype,
there has been a focus on biotype but it
·
Biotype – thickness of gingiva in
bucco-lingual direction
·
Phenotype – contour gingiva,
underlying bony architecture, and width of keratinised tissue
Thin gingival biotypes are likely to have more chances
of recession.
Factors to consider
·
Extraction Vs non-extraction: in
both scenario the bone height decreases, but in different locations, anterior
extraction treatment = 2mm reduction, non-extraction = 1.2mm. www.orthoinsummary.com/blog
·
Dehiscence exist pre treatment
·
Thicker the gingiva, the better Yared
2006
·
Initial position of the tooth
decides its periodontal future
·
Thickness varies in various areas
of the mouth.
·
Oral hygiene major factor of
recession Melsen 2005.
CBCT
·
Aren’t really telling us the whole
story –
·
Size of the image of a CBCT is
limited by the radiation dose, and typically is 0.3-0.6mm3 of voxel size
·
Tissue less than 0.6mm appears as a
absent in CBCT giving false positive results ( Redua 2020)
Lower incisor proclination and recession:
·
Systematic review Kalina no correlation
between proclination and gingival recession. (Kalina 2022)
Understanding
Recession = Thin gingiva + proclination +
periodontitis
Conten
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Great podcast, summarises long lectures into a few minutes, with great written summaries in the description. IDEAL ORTHODONTIC PODCAST