DIGITAL IMAGING IN ORTHODONTICS
INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com
PRINCIPLES OF DIGITAL IMAGING Normal 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) www.indiandentalacademy.com
CEPHALOGRAM CONVENTIONAL (ANALOG)
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 www.indiandentalacademy.com
DIGITAL IMAGING DISADVANTAGES
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 www.indiandentalacademy.com
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. www.indiandentalacademy.com
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.
ďƒ˜ Pointing and clicking with the mouse can easily measure Bolton discrepancies and arch length tooth size discrepancies. www.indiandentalacademy.com
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 www.indiandentalacademy.com
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 www.indiandentalacademy.com
SURE SMILE TECHNOLOGY
OraScanner -a lightâ€‘ 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
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 www.indiandentalacademy.com
GENERATED 3-D MODEL
STEREO LITHOGRAPHIC MACHINE
TRIMMING INVISALIGN CUTTER www.indiandentalacademy.com OF INVISALIGN
Use of INVISALIGN appliance in the treatment of moderate crowding
ADVANTAGES OF INVISALIGN
Improved esthetics Ability to remove the appliance
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 www.indiandentalacademy.com
COMPUTERIZED SURGICAL PREDICTION IMAGING
“A useful indicator of potential treatment outcomes with different techniques & the orthodontist’s ability to achieve them” www.indiandentalacademy.com
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.
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 www.indiandentalacademy.com
Pt â€“ A
Skeletal Class III
Hypoplastic Maxilla and Prognathic Mandible
Pre-Surgical after Dentoalveolar Decompensation
Manual Prediction (Cut and Paste Method)
Maxillary Advancement â€“ 4 mm Mandibular setback
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 www.indiandentalacademy.com Lower Lip
by 2.8 mm
Comparison between Manual and Computerized Prediction OTP Treatment Planning (2).lnk
•2 •3 •4 •5
Manual Superimposition www.indiandentalacademy.com
•2 •3 •4 •5 Pre Surgical Computer Superimposition
Actual Post Treatment
COMPARISION OF CURRENT PREDICTION IMAGING PROGRAMS 5 programs with the largest market share was chosen DENTOFACIAL PLANNER PLUS
WINDOWS 98 Platform
WINDOWS 98,2000,XP Platform
QUICK CEPH SYSTEM
WINDOWS XP Pro
J.Dempsey Smith and Paul M. Thomas, AJO May 2004 www.indiandentalacademy.com
Case No:1 Short Face Patient (Actual and Predicted Outcomes) Surgery Done â€“ 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 www.indiandentalacademy.com
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 www.indiandentalacademy.com
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 www.indiandentalacademy.com
Applications of CT and MRI in orthodontics
Magnetic Resonance Imaging EquipmentGantry â€“ 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. www.indiandentalacademy.com
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. www.indiandentalacademy.com
Importance of MRI imaging of the TMJ ďƒź Determine the structural relationship between the Condyle, Articular disc and Glenoid fossa ďƒź 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. www.indiandentalacademy.com
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 www.indiandentalacademy.com
ADVANTAGES OF DIGITAL IMAGING IN DIAGNOSIS AND MANAGEMENT OF IMPACTED TEETH
IO - Xray
Conventional radiography is by far the standard method for viewing impacted canine but it has following short comings, ďƒ˜ Difficulty in assessing position (buccal/palatal) ďƒ˜ Difficulty in assessing level and extent of resorption of adjacent teeth www.indiandentalacademy.com
IMPACTED MAXILLARY CANINE PERIAPICAL RADIOGRAPH
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 www.indiandentalacademy.com
BUCCALY POSITIONED IMPACTED MAXILLARY CANINE
MAXILLARY CANINE PALATALLY POSITIONED IMPACTED
ASSESSMENT OF ROOT RESORPTION USING CT SCAN Periapical radiograph â€“ 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 www.indiandentalacademy.com
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. www.indiandentalacademy.com
The orthodontist as an architect of the smile needs to identify and quantify the elements of the smile that needs ď‚§ correction, ď‚§ enhancement ď‚§ 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 patientâ€™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
Before expansion(more of dark space on smile) www.indiandentalacademy.com 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 â€˘ Cost â€˘ 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. www.indiandentalacademy.com
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. â€˘ The brackets manufactured for lingual orthodontics is based on digital registration of the malocclusion. â€˘ 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
â€˘ 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.
â€˘ 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 â€˘ In parallel with this design process, the archwire definition data are generated. www.indiandentalacademy.com
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. www.indiandentalacademy.com
Bracket manufactured by RPT
ADVANTAGES OF DIGITAL IMAGING IN DIAGNOSIS OF SLEEP APNEA www.indiandentalacademy.com
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. www.indiandentalacademy.com
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
THE PAST IS A SOURCE OF KNOWLEDGE AND FUTURE IS A SOURCE OF HOPE. TO LOVE THE PAST IMPLIES A FAITH IN THE FUTURE.
www.indiandentalacademy.com Leader in continuing dental education
Published on May 8, 2014
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