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Outline
•
Introduction
•
Technologies used
• Techniques
• Customized
precision prescriptions
•
Semi-customed appliances
• Fully
customized appliances
• Summary
· References
1-
Introduction
The power,
speed, low cost and portability of modern computers has made substantial
computing
power readily available while digital design and manufacturing techniques
are now
transferable into orthodontic practice.
Customisation types
Customised
precision prescription appliances or orthodontic treatment can be delivered by either:
•
Customising or individualising brackets to the patient’s tooth morphology
•
Customising the bracket-tooth surface composite/resin interface to the
patient’s tooth morphology and planned
treatment needs
•
Customising the archwires to the patient’s tooth morphology and planned
treatment needs.
• Using
selected prescriptions to semi-customise the appliance
• A
combination of the above
• Aligners
2-Technologies Used
• Digital imaging
Photographs and radiographs now makes it easy to transmit or
upload patient data to
sites that are geographically distant
• Computer modelling
Ability to visualise, manipulate and test treatment outcomes
• Robotics
Archwire fabrication
• High technology materials
and manufacturing technique
Metal injection moulding and nickel
titanium archwires
3-Techniques
• Records
o Digital photographs
o Digital radiographs
o Impressions
In order to select the size of tray required to fit the patient,
the bite registration is done
first and then use to select the tray size as described in the Align Technology
PVS
Impressions Overview.
Errors in impressions :
Loupes are recommended for inspecting the impressions prior to
sending them off to the
service provider.
Ø gingival margins
Ø occlusal surfaces
Ø molar area
Ø material adhesion
Ø tooth by tooth inspection
Ø • Cone beam CT
o One advantage of this technique is
that it brings distortion-free representation of he
subsurface anatomy to SureSmile’s 3D virtual setup simulations.
o The use of CBCT involves the use of
ionizing radiation but allows the incorporation of subsurface detail into the
3D data capture.
o It would eliminate the use of
impressions or an intra-oral scanner.
o Kau et al (2010) investigated the
difference between digital models derived from CBCT
using anatomage InVivo Dental software and compared these with OrthoCAD models generated from dental impressions.
o Results: linear anatomical
measurements were insignificantly different between the two methods although resolution of dental anatomy was less
good from CBCT
than from digital models derived from impressions.
• Intra-oral scanners
o Allow direct capture of tooth anatomy
and eliminate the need for impressions.
o Several intraoral scanning systems
are available or in advanced stages of development:
Ø Cadent iTero™
Ø 3M Lava™ COS
Ø DImensional Photonics International 3D
Ø Orametrix Orascanner™
Ø D4D Technologies Intraoral Digitizer
4-Customised precision prescriptions
• Information
about the patient specific prescription will be required. This may be completed online but a printed copy is normally required to be
sent with the PVS impressions
to the service provider
o Demographic details of patient
o Orthodontist’s details
o Preferred appliances
o Selective torque values
o Teeth to be bonded
o Teeth to be extracted
o Buccal segment relationship required
at the end oftreatment
o Final overbite and overjet required
at the end of treatment
o Any spacing to be left
o Planned tooth replacements or
restorations
o Planned interproximal reduction
o Expansion or contraction of molar
widths
o Mesial or distal molar movement
o Upper incisor edge alignment
Constructing computer model from impressions :
• CT scanning
oThe impression can be scanned using
and industrial CT scanner
• Surface scanning
o 3D surface scanning
• Destructive scanning
o Removes
slices about 0.003 inch wide and a digital camera then takes a 2D scan after each slice. A computer stacks together around 300 of these
digital images to create the 3D model.
Limitations of digital models
• Observing
crossbites.
• Detail
of midlines, occlusal anatomy and wear facets.
• Quantifying
precise interdigitation.
5-Semi-customed appliances
The term semi customised appliances is used to describe the
variations from standard straight
wire technique, such as inverting brackets or mixing of brackets from different
prescriptions in order to produce specific tooth movements of
individual patient’s needs .they
are :
• More
variability than fully programed appliances .
• Not
fabricated specifically to the pts needs.
• Uses
mixed prescription Straight Wire appliance
6-Fully-customed appliances
Designed to meet the spesific needs of the pt’s malocclusion
• Oramco
–Insignia
• Incognito
–custom made lingual appliances
• Custom
SL appliances
• Clear
aligners
• OrthoCAD
• SureSmile
7-Summary
ü Customised precision prescription
appliances offer several potential advantages .
ü The extent
to which they are translated into tangible benefits is as yet unclear.
ü Overall, impressed with the early
experiences with this technique and are convinced
it will become the preferred way of placing fixed appliances in the future.
ü The learning curve in the early
stages is sheepish but perseverance makes orthodontics even more enjoyable! Well worth a try.
8-References
• Customized
precision prescription appliances
Excellence in orthodontics 2012.
• Postgraduate
Notes inOrthodontics (University Of Bristol).
• Contemporary
Orthodontics by William Proffit,chapter 10
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