Digital imaging in orthodontics /certified fixed orthodontic courses by Indian dental academy

DIGITAL IMAGING IN
ORTHODONTICS

www.indiandentalacademy.com

INDIAN DENTAL ACADEMY
Leader in continuing dental education


PRINCIPLES OF DIGITAL IMAGING
Normal X-ray

Digital X-ray

Silver halide grains in x-ray
films perceived as different
shades of gray by the
human eye due to varying
densities

Silver halide grains are
replaced by small lightsensitive electronic
sensors which produce an
electric signal depending
on the voltage recorded
by the sensor

(this analog electronic signal is converted into a digital signal by a capture
card [frame grabber] and represented by shades of gray ranging from
values 0 to 255)

CEPHALOGRAM
CONVENTIONAL
(ANALOG)


DIGITAL

OPG
CONVENTIONAL


DIGITAL

METHODS OF IMAGE ACQUISITION

INDIRECT
a) Scanner
b) Phosphor plate

DIRECT
a) Charged Coupled Device
(CCD)

b) Complementary metal oxide
semiconductor (CMOS)


DIGITAL IMAGING THROUGH CCD
SCINTILLATOR
- converts x-radiation to photons
(light)
FIBRE OPTIC LAYER
- conducts photons to CCD
- stops x-radiation
CCD
- converts photons to electrons
(charge)
ELECTRONIC CIRCUIT
- amplifies the signal
- converts the analog signal to digital

DIGITAL IMAGING
DISADVANTAGES

ADVANTAGES










Dose reduction
Image prediction
Reduced overall time
Measurements [Digital
Calipers]
3-D Reconstruction
Contrast enhancement
Storage
Teleradiology
Environmentally Friendly

► Cost
► Reduced Sensor
Dimension
► Cross-Infection Control


There are five basic techniques for producing
digital models:
1)
2)
3)
4)
5)

Stereophotogrammetry
Laser scanning
Destructive imaging
White light scanning
CT scanning


Stereo pairs of images are captured from two converging
cameras and three dimensional reconstruction occurs in
only those areas that are visible to both cameras

A new Laser scan based approach called
e-models was developed to improve the accuracy
and efficiency of orthodontic diagnosis,
treatment planning, and bracket placement.

DIGITAL MODELS
The orthodontist sends the impression and bite registration to
GeoDigm/OrthoCAD. E-models are constructed through proprietary
laser scanning process
USES
Using the e-model software,
the clinician can move, rotate,
or zoom in on the model and
make measurements in any
plane or orientation.

 Pointing and clicking with the mouse can easily measure Bolton
discrepancies and arch length tooth size discrepancies.

In addition, the software
has an articulation
feature that enables the
clinician to identify
centric occlusion and
point of initial contact.

One of the latest
innovations in 3D digital
treatment planning called
E-plan, which simulates
multiple treatment
options.


VIRTUAL SET UP

INCISORS AND MOLARS ARE REPOSITIONED
AS REQUIRED

ONE CAN CHOOSE PREFERRED BRACKETS, WIRES
FROM THE AVAILABLE STRAIGHT WIRE SYSTEM

MAXILLARY AND MANDIBULAR
TEETH CAN BE SLID
INTO THEIR PROPER POSITIONS
ALSO ONE CAN CORRECT THE
BRACKET POSITIONS FOR
BETTER INTER AND INTRAARCH
RELATIONSHIPS

EXTRACTIONS WITH
RESULTANT SPACE CAN BE
MANIPULATED MANUALLY OR
AUTOMATICALLY


BRACKET PLACEMENT USING
OrthoCAD SOFTWARE


(Wand with miniature video
camera, LED and tip)

Viewing the teeth on monitor
screen with the wand and
temporarily setting the
bracket on the tooth


ORTHOCAD BRACKET PLACEMENT

Initial bracket placement

Adjusting to the correctwww.indiandentalacademy.com
position Final correct bracket placement

ADVANTAGES OF ORTHOCAD BRACKET PLACEMENT
1) Consistent, accurate bracket placement
2) Expresses the full potential of the appliance
3) Yields better treatment outcome
4) Shorter treatment time
5) Allows to compare multiple treatment scenarios

SURE SMILE TECHNOLOGY

OraScanner -a light‑ based
imaging device

Diagnosis and
treatment planning

Obtaining a
Virtual model

"virtual bracket placement"

Wire bending robot
Producing arch wires

and selection of the
arch wire sequence and progression


INVISALIGNERS

PRETREATMENT RADIOGRAPHS
AND IMPRESSIONS SENT TO
INVISALIGN LABORATORIES

IMPRESSIONS ARE CONVERTED
TO PLASTER MODELS AND
CHECKED FOR QUALITY


MODELS ARE COATED WITH
PROTECTIVE
SHELLS AND ENCASED IN A MIXTURE
OF RESIN AND HARDENER

EACH TRAY IS PLACED IN A
DESTRUCTIVE SCANNING
MACHINE

AFTER CHEMICAL CURING, BLOCKS OF
HARDENED RESIN WITH PLASTER
MODELS ARE OBTAINED

DESTRUCTIVE
SCANNING

GENERATED 3-D
MODEL

STEREO LITHOGRAPHIC
MACHINE

TRIMMING
INVISALIGN CUTTER
OF INVISALIGN

Use of INVISALIGN appliance
in the treatment of moderate crowding


ADVANTAGES OF INVISALIGN



Improved esthetics
Ability to remove the appliance

DISADVANTAGES








All permanent teeth should be fully erupted
It does not allow for continued eruption of teeth or dental arch
changes during growth
Major restorative work should be performed before the
commencement of treatment
Treatment plan cannot be changed once the appliance series has
begun
Only crown position is displayed in the computer
Inability to integrate hard and soft tissues
It is expensive

COMPUTERIZED SURGICAL
PREDICTION IMAGING

“A useful indicator of
potential treatment
outcomes with different
techniques & the
orthodontist’s ability to
achieve them”

VIDEO IMAGING & PREDICTION
The software superimposes the patients lateral
photograph onto the lateral cephalogram to a proportionate
scale.
When the computerized predictions are made, the
patient can now have an idea of his / her probable facial
appearance after the planned treatment.

Pre treatment

Computer prediction


ADVANTAGES

DISADVANTAGES

 Stored in computer memory
and recalled easily
 Several alternative
predictions possible much more
rapidly
 Enhancement of the doctorpatient communication
 Promotes greater
understanding and satisfaction
with the outcome, as long as the
patient recognizes that the

 Software design
dependent and technique
sensitive
 Expensive
 Poor soft tissue
definition in particular
areas

Prediction is only a goal and not a guarant

Pt – A

Age: 24/M

Diagnosis:

Skeletal Class III

Hypoplastic Maxilla and Prognathic Mandible


Pre-Treatment Profile


Pre-Surgical after Dentoalveolar Decompensation


Manual Prediction
(Cut and Paste Method)

Maxillary Advancement – 4 mm
Mandibular setback

- 4mm

Soft tissue changes associated with
treatment
MAXILLARY ADVANCEMENT
Nose : Slight elevation of tip
Base of upper Lip : protracted by 1 mm
Upper Lip : protracted by 2.8 mm
and shortens by 1.5 mm

MANDIBULAR SETBACK:
Chin retracted by 4 mm
Lower Lip

by 2.8 mm

Comparison between Manual and Computerized Prediction
OTP Treatment Planning (2).lnk

Manual Superimposition

Computer Superimposition

•1

•2
•3
•4
•5

Pre-Surgical

C:ss.pat

Manual Superimposition

•1

•2
•3
•4
•5
Pre Surgical
Computer Superimposition

Pre- Surgical

Computer Prediction


Actual Post
Treatment

COMPARISION OF CURRENT PREDICTION IMAGING
PROGRAMS
5 programs with the largest market share was chosen
DENTOFACIAL PLANNER
PLUS

DFP

WINDOWS 98 Platform

DOLPHIN IMAGING

DI

WINDOWS 98,2000,XP
Platform

QUICK CEPH SYSTEM

QC

MACINTOSH Platform

VISTA DENT

GAC

WINDOWS XP Pro

PRACTICE WORKS

OTP

WINDOWS

J.Dempsey Smith and Paul M. Thomas, AJO May 2004

Case No:1 Short Face Patient (Actual and Predicted Outcomes)
Surgery Done – Mandibular Advancement


Case No:2 Long Face Patient (Actual and Predicted Outcomes)
Surgery done - Maxillary impaction and mandibular set back


RESULTS
 Dentofacial planner ( DFP) was the clear favorite
in both observer group [short face and long face]
 Dolphin imaging (DI) and Quick ceph (QC) were the
next favorites with DI handling long face subjects
better and QC more competent with the short face
group
 For GAC and OTP- both consistently rated poor
regardless of facial type

J.Dempsey Smith and Paul M. Thomas, AJO May 2004

PREDICTION IMAGING PROGRAMS
1) Prescription Planner/Portrait software system (PP)
2) Orthognathic Treatment Planner (OTP)
3) Dentofacial planner (DFP)
4) Quick Ceph (QC)
5) Dolphin Imaging (DI)
6) Vistadent (GAC)
7) Orthognathic Prediction Analysis (OPAL)
8) Nemoceph
9) Dr.Ceph


THREE DIMENSIONAL IMAGE CAPTURING SYSTEM
FOR FACIAL PROFILES (C3D software)


The analog picture of a stereopair of video cameras
are converted into a digital mode with a standard frame
grabber (A device for converting a television picture to a digital
array of numbers). The software does the entire capture in 50
milliseconds

3D imaging of the face enables the orthodontist to evaluate the face
from any direction. Here, a skeletal Class III case is displayed in
different views

Applications of CT and MRI
in orthodontics


Magnetic Resonance
Imaging
EquipmentGantry – houses the
patient. Patient is
surrounded by magnetic
coils
Magnetic fields are caused by rotating
electric charges.
Essentially it is the- imaging of the
water in the tissue.
Images are generated from protons of
the hydrogen nuclei of water.

 Indications of MRI
 MRI imaging of TMJ
 Cleft lip and palate
 Tonsillitis and adenoiditis, optimum assessment of upper
airway
 Cysts, infections and tumors

 Contraindications
 Patients with cardiac pacemakers.
 Patients with cerebral metallic aneurysm clips.- Slight
movement of the clip could produce bleeding
 Stainless steel and other metals produce artifacts ; obliterate
image details of the facial area.

Importance of MRI imaging of the TMJ
 Determine the structural relationship between the Condyle,
Articular disc and Glenoid fossa
 Detect inflammation, hematoma and effusion for the soft tissue
components


 Short comings
 Inability to identify ligament tears or perforations
 Dynamics of tissue joint not possible
 Cannot be used in patients suffering from
claustrophobia


NewTom QR 9000 CT Scanner
In a single scan, the x‑ray
source and a reciprocating x‑ray
sensor rotate around the
patient's head and acquires 360
pictures in 17 seconds of
exposure time.
The entire maxillofacial volume
(13 cm‑diameter field of view) is
enlarged, and the patient
receives an absorbed dose
similar to a peri apical survey of
the dentition.

The 360 acquired images
undergo a primary
reconstruction to
mathematically replicate the
patient's anatomy into a single
3D volume.
Applications
Location of impacted tooth
relative to roots of adjacent
teeth

ADVANTAGES OF DIGITAL IMAGING IN
DIAGNOSIS AND MANAGEMENT OF
IMPACTED TEETH


IO - Xray

OPG

Occlusal View

Conventional radiography is by far the standard method for
viewing impacted canine but it has following short comings,
 Difficulty in assessing position (buccal/palatal)
 Difficulty in assessing level and extent of resorption of
adjacent teeth

IMPACTED MAXILLARY CANINE
PERIAPICAL
RADIOGRAPH

COMPUTERIZED TOMOGRAPHY


TECHNIQUE OF ACQUIRING CT
Tomogram of the head
showing the cutting
direction of the beam
through the anterior
part of the maxilla
perpendicular to the
long axis of the
maxillary incisors.

Slice thickness of 2mm are normally taken for assessing
the canine position

BUCCALY POSITIONED IMPACTED MAXILLARY CANINE

MAXILLARY CANINE PALATALLY POSITIONED IMPACTED


ASSESSMENT OF ROOT RESORPTION USING
CT SCAN
Periapical radiograph – not
CT scan of the same region
showing extent of resorption

showing the extent of
resorption of lateral incisors
palatally

Lateral incisor after extraction;
Palatal view showing the total extent of
the resorption

DIGITAL IMAGING AND
SMILE ANALYSIS


The flaw in traditional smile
analysis has been based on the
tracing of the lateral
cephalogram, which is taken in
repose (at rest)
Due to this limitation incisor
position has been determined
from a static rather than a
dynamic record.

The orthodontist as an architect of the smile
needs to identify and quantify the elements of the smile that
needs
 correction,
 enhancement
 and improvement
as well as identifying the positive elements of the smile that
must be saved.


Smile Analysis with the SMILE MESH PROGRAMME
This methodology was first used manually by Hulsey and later
modified and computerized by Ackerman
The frame that best represents the patient’s social smile is selected
and saved as a JPEG file.
The smile image is then opened in a program called SmileMesh,
which measures 15 attributes of the smile


Smile mesh analysis after RAPID MAXILLARY EXPANSION
BEFORE RME

AFTER RME

Before expansion(more of dark space on smile)
After expansion(reduced dark space after treatment)

RAPID PROTOTYPING
(RPT)


RAPID PROTOTYPING (RPT)
It is a group of manufacturing processes that enable the direct
physical realization of 3D computer models. This technology
converts the 3D computer data provided by a dedicated file
(STL file) format directly to a physical model, layer by layer
with a high degree of accuracy.

STEREOLITHOGRAPHY (SLA)
Stereolithography (SLA) is the most widely distributed
process of RPT


APPLICATIONS :
1. Custom made brackets for individual patient anatomy
of crowns.[lingual brackets]
2.Various mock surgery procedures can be practiced on
the 3D Biomodels, allowing optimal input into the
management decision, pre-operative planning and
choice of surgical technique.


LIMITATIONS
• Cost
• Radiation exposure of the patient (CT
scanning)
With wider use and further technological
development, these drawbacks will be
minimized. The 3D SLA biomodels may in
future become an adjunct to diagnosis, and
treatment planning in Orthognathic surgery.

BRACKET MANUFACTURING BY RPT
Using state-of-the-art CAD/CAM technology, the two
normally separate processes of bracket production and
bracket positioning are fused into one unit.
• The brackets manufactured for lingual orthodontics is
based on digital registration of the malocclusion.
• The brackets are then individually designed and optimally
positioned in the computer using Rapid prototyping.


A silicone impression is used for
preparation of a malocclusion cast
and a therapeutic set-up.
• The set-up is digitized with a highresolution 3D scanner.
• The individual brackets are
generated on this surface at a
computer workstation.
• First, appropriate pads are designed
on the lingual surfaces of the teeth.
• The next step is optimal
positioning of the bracket bodies


• The brackets are then constructed on
a high-precision prototyping
machine from a wax-like material.
These wax blanks are embedded and
cast in gold.

• As the brackets are made of an alloy
with a high gold content, they offer
an interesting alternative especially
for patients who are allergic to nickel
• In parallel with this design process,
the archwire definition data are
generated.

ADVANTAGES OF BRACKETS
FABRICATED BY RPT :
1.

The exact correspondence of the bracket
and tooth interfaces results in a positive
lock when the bracket is pressed onto the
tooth, making incorrect positioning
unlikely.

Normal Lingual Brackets

2. Reduced bracket loss rate due to the shorter
lever arm in the event of masticationinduced shearing.
3. Exact finishing due to better expression of
tip & torque.
4. Enhanced wearing comfort due to optimum
size and shape of the bracket.

Bracket manufactured by
RPT

ADVANTAGES OF
DIGITAL IMAGING IN
DIAGNOSIS OF
SLEEP APNEA

Disadvantages Of Lateral Cephalograms:
1.Two dimensional data only of evaluating a complex
three dimensional anatomical structure
2.Difficulty in taking cephs in supine position
3.Static investigation is only possible


CT Advantages:
1.Volumetric & 3-dimensional
reconstructions of the airway
and other peripharyngeal
structures are possible.
2.The study can be performed
in the supine position.
3. High spatial resolution
Volumetric reconstruction and
3-dimensional imaging is only
possible with the newer Helical
CT scanner.

MRI Advantages:
1.Non invasive with high contrast resolution
2. Allows scanning in multiple planes, allowing the whole
airway to be visualized at one time.
3.Allows examination of the entire pharynx in a short time
4.Drawbacks of radiation exposure minimized.


A single excitation is used to obtain mid-sagittal and axial
projections during transnasal shallow respiration at rest,
simulation of snoring.

Normal upper airway

Uvula & narrowed airway


Awake position

Asleep state


THE PAST IS A SOURCE OF KNOWLEDGE
AND FUTURE IS A SOURCE OF HOPE.
TO LOVE THE PAST IMPLIES
A FAITH IN THE FUTURE.


Thank you

Leader in continuing dental education


Digital imaging in orthodontics /certified fixed orthodontic courses by Indian dental academy

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