Recent advances in diagnosis and treatment planning1 /certified fixed orthodontic courses by Indian dental academy


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The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.

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Recent advances in diagnosis and treatment planning1 /certified fixed orthodontic courses by Indian dental academy

  1. 1. INDIAN DENTAL ACADEMY Leader in continuing dental education
  2. 2. Recent Advances in Diagnosis and Treatment Planning.
  3. 3. Introduction Original Diagnostic records consisted of set of study models and patient‘s orthodontic problems Discovery of X-rays by Roentgen in 1895. Traditional 2-D cephalographs also known as Roentgenographic cephalometry introduced by Broadbent, 36 years later.
  4. 4. Introduction With the arrival of the cephalometric technique and its increasing popularity clarification of the anatomic basis for malocclusions became possible.
  5. 5. Introduction 1. 2. Several reasons for limited validity of the 2D Cephalometry‘s scientific method : A conventional headfilm is a 2D representation of a 3D object. Cephalometric analyses are based on the assumption of a perfect superimposition of the right and left sides about the midsagittal plane.
  6. 6. Introduction 3. a) b) c) d) e) A significant amount of external error, known as radiographic projection error, is associated with image acquisition. Size Magnification Distortion Patient positioning Projection distortion *
  7. 7. Introduction 4. 5. Manual data collection and processing in cephalometric analysis has been shown to have low accuracy and precision. Errors in location of landmarks due to the lack of well defined outlines, hard edges and shadows.
  8. 8. Introduction Despite these limitations Various ceph. analyses have been developed to help diagnose skeletal malocclusions and dentofacial deformities.
  9. 9. Introduction Integration of computers and ceph technology in the 1970‘s Complex statistical analysis of growth patterns and dentoskeletal relations were estb.
  10. 10. Introduction Various technological aids were introduced. IMAGING; most important tools used by an orthodontist to measure and record the size and form of craniofacial structures. Traditionally used to record the status quo of limited or grouped anatomical structures.
  11. 11. Introduction Despite the diverse image acquisition technologies currently available Standards have been adopted in an effort to balance the anticipated benefits with the associated costs and risks.
  12. 12. Some of the recent advances which have taken place in the field of diagnosis and treatment planning are as follows;
  13. 13. radiographic image acquisition 3D radiographs holographs Arthrography CT and MRI II. Cephalometric application analysis and planning
  14. 14. Imaging and Image acquisition Images Conventional ANALOG PROCESS Contemporary DIGITAL PROCESS
  15. 15. Imaging and Image acquisition       Necessity : Manipulation of data on a computer Facilitating complex analysis Organisation of data (CT and MRI imaging) Biology: Reduce patient radiation exposure Practicality: Decreases storage needs transmission of images (teleradiology)
  16. 16. Imaging and Image acquisition Digital Photography: INPUT PROCESSING OUTPUT
  17. 17. Imaging and Image acquisition   Digital Camera: uses a CCD (charged coupled device) or a CMOS (complementary metal oxide) semiconductor as a image sensor rather than film. CCDs are small sensors light electric charge
  18. 18. Imaging and Image acquisition Image quality • sensor pixel count •Tonal range • color purity • Lighting etc….. Compression using JPEG (Joint photographic experts group format) or TIFF(Tag image file format).
  19. 19. Imaging and Image acquisition 1. 2. 3. No. of images stored depend on Capacity of the storage device Resolution at which the picture was taken Amount of compression used.* 3:1 – no loss of information upto 20:1- some loss , but clinically insigf.
  20. 20. Video Imaging. With the integration of computers and cephalometric technology in the 1970s, complex statistical analyses of growth patterns and dentoskeletal relations were established. The speed of computerized cephalometric programs has helped streamline the laborious manual measurement of patient cephalograms and the creation of the visualization treatment objective (VTO).
  21. 21. Video Imaging. In the VTO of an orthognathic surgery case, the clinician classically has used acetate templates of the teeth and jaws to predict orthodontic and surgical movements and the final profile is determined by the reaction of the soft tissue to the hard tissue movements.
  22. 22. Video Imaging. Cut photographs and move the sections in a way that somewhat simulates the surgical outcome, but does not allow the planner to visualize limiting factors such as the dental relationships (overjet) or differential soft tissue reaction to hard tissue movement. Gaps in the manipulated photographs are unavoidable.
  23. 23. Video Imaging. Cephalometric digitizing programs may be used in automating these predictions and, in both cases, single line profile renderings serve as the profile outline of the final treatment goal. Profile line renderings may represent a reasonable feedback system for the orthodontist, but has little cognitive value to the patient.
  24. 24. Video Imaging. Video imaging technology allows the orthodontist to gather frontal and profile images and modify them to project overall esthetic treatment goals The video image is much more realistic than photograph simulation and it is much easier for the patient to comprehend than just the soft tissue profile of a cephalometric tracing.
  25. 25. Video Imaging.     Coordinating images and cephalogram: Digitizing the ceph and then matching the size of the video image to it Digitizing the ceph and then sizing the ceph to an existing video image (loss of calibration) Gathering the video image of a ceph through a calibrated video camera and matching it to an existing video image Simultaneous image gathering and ceph. radiography.
  26. 26. Video Imaging.(advantages)      Graphic method of communication with patients Formation of visual template in treatment planning. Quantification of treatment plans. Ease of communication with others of the similar profession Less time consuming and more efficient .
  27. 27. Digital Radiographs          Process of data collection RVG Dentoptix digital radiographic system Cephalometric applications DIGICEPH DIGIGRAPH Dentofacial Planner Vista dent Teleradiography
  28. 28. Digital Radiographs X Ray Sensor Data collection: IMAGE Electrical charge digitizer • CCDs • Amorphous Selenium • Amorphous Silicon • Phosphor plates
  29. 29. Digital Radiographs (RVG) Basic Principles: sensor head object x-ray source transmitter scintillator CCD converter amplifier fibre optic PC quantizer amplifier receiver
  30. 30. Digital Radiographs (RVG) CCD -analogy The charge of the pixel is proportional to the amount of light
  31. 31. X-ray imaging with CCD Scintillator - converts x-radiation to photons (light) Fibre optic layer - conducts photons to CCD - stops x-radiation pixels CCD - converts photons to electrons (charge) Electronic circuit - amplifies the signal - converts the analog signal to digital
  32. 32. Dixi2 scintillation material  x-rays crystalline   light  x-rays  amorphous  light new crystalline scintillation material no scattering no need for fibre optic layer thicker scintillator can be used more light to CCD better detective quantum efficiency
  33. 33. Dixi2 digital intraoral radiography real time image acquisition view delay 1 - 4 s pixel size: 19 / 38 µm (selectable) very high resolution optimal shape and size of the sensor        Dixi2 sensor thickness 4 mm sensor cable diameter 3 mm
  34. 34. Dixi2 digital intraoral radiography      Dixi2 long reach, 27 m to PC no reset between exposures fast multiple exposures - study templates versatile and easy-to-use Dimaxis software DICOM compatible 0301
  35. 35. Digital Radiographs      DENOPTIX A radiographic technique which eliminates silver halide film Storage Phosphor imaging plates * High costs of scanners (laser) needed to read the images. Adv. over CCDs no wires and rigid sensors. Available in thin flexible films.
  37. 37. Principle of phosphor plate imaging Phosphor particles store the x-ray information laser beam releases the stored information exposure A/D digital data erasure of the plate for reuse 0301
  38. 38. Digital Radiographs Cephs and OPGs : same cassettes can be used Intensifying screen has to be removed* Same machine and settings can be used for DENOPTIX and regular Cephs and OPGs .
  39. 39. Digital Radiographs This digital image can be then manipulated using various software programs. Soft tissue filtering can be done afterwards with the software
  40. 40. Digital Radiographs Advantages: 1. 2. 3. 4. Alternative to conventional film No dark room or scanner required No chemicals, film mounts or film required Saving staff time
  41. 41. Digital Radiographs 5. 6. 7. Environmental friendly; no heavy metal wastage Transmission of images Enlargement of any area of interest
  42. 42. Cephalometric Applications Orthodontic treatment involves synthesizing functional and esthetic treatment goals. Ceph. applications offer various treatment planning procedures. Various methods of cephalometric analysis; 1. Hand tracing and direct measurements 2. Direct computer digitization of the ceph. 3. Indirect computer digitization of the ceph.
  43. 43. Cephalometric Applications  Direct digitization; Analog info. converted into digital info. Digitizing tablet Electronic pen mouse Cross hair cursor
  44. 44. Digitizing tablet with cross hair cursor.
  45. 45. Cephalometric Applications Modes of digitization; 1. Point mode:  Discrete location of individual landmarks  Location of landmarks in a predetermined sequential manner  Visual ceph. generated by connection of dots by lines and curves.  Close to accurate landmark identification
  46. 46. Cephalometric Applications Stream mode digitization:  Stream of coordinate points recorded as the radiographic contour is traced  Stream controlled by programmable options  Digitizing cursor or mouse to be used  More technique sensitive than point mode  Less time consuming  Landmark identification is less accurate
  47. 47. Cephalometric Applications    DIGICEPH Method for computerized digitization, analysis and superimposition 13 cephalometric analysis Developed by Centre for Bio-medical Engineering, IIT, Delhi and dept. of Dental Surgery, AIIMS, Delhi.
  48. 48. Cephalometric Applications Features  10 image storage data bank. (1 temp and 9 perm)  Requires a computer, printer, backlit hipad digitizer and digiceph software  Uses point mode of digitization
  49. 49. Cephalometric Applications       DIGIGRAPH Introduced by Dolphin imaging systems Non-radiographic system ‗Digigraph workstation‘ Video images also possible VTO Reduces time required for records.
  50. 50. Cephalometric Applications System design: The DigiGraph Work Station is about 5 feet long, 3 feet wide and 7 feet high. The main cabinet contains the electronic circuitry, and the patient sits next to the cabinet in an adjustable chair similar to those used with cephalometers.
  51. 51. Cephalometric Applications The head holder is suspended from a beam, supported by a vertical column attached to the cabinet (Fig. 5). more comfortable than cephalometer head holders, allowing the patient to remain in the holder for several minutes. Ear rods and forehead and posterior head pieces are used to minimize patient movement. The ear rods can be removed so that facial and intraoral images can also be recorded while the patient is sitting in the adjustable chair.
  52. 52. Cephalometric Applications A model board can be inserted into the head holder, and images of various views can be recorded (Fig. 6) .
  53. 53. Cephalometric Applications A light box can also be attached to the head holder for imaging headfilms, wristfilms, laminagraphic films, and panoramic x-rays (Fig. 7).
  54. 54. Cephalometric Applications The video monitor (Fig. 8) is attached that can be rotated as the operator moves. Images are as sharp as those on a standard color television. The images, text, and numerical data can be displayed, stored, and modified using either a light pen or a standard computer keyboard.
  55. 55. Cephalometric Applications Any image appearing on the screen can be reproduced instantaneously with one of three "hard copy" output devices: • Sony video imager— makes 5 " x 7 " color prints in 60 seconds (Fig. 9). • Polaroid freeze-frame camera— produces Polaroid prints in 10 seconds; a 35mm slide back can be added to make slides, which can be sent out for processing. • Hewlett Packard Paintjet printer— makes 8 " x 10 " paper color copies in 4 to 8 minutes.
  56. 56. Cephalometric Applications The digitizing handpiece (Fig. 10) is used to record cephalometric data while the patient is in the head holder. The removable, sterilizable tip of the handpiece is placed directly on the patient to record a series of facial and intraoral landmarks. As each landmark is located, the handpiece button is depressed and the location is recorded in threedimensional coordinates (x,y,z). Each time the handpiece button is depressed, an audible sound is picked up by an array of four microphones on the beam. The time it takes the sound to reach each of the microphones determines the landmark location.
  57. 57. Cephalometric Applications Some practices may need additional work stations where records are not taken, but can be viewed, modified, or analyzedConsultation Station (Fig. 11) it can be placed in the orthodontist's private office. It is built on casters and can easily be moved from chair to chair in the operatory.
  58. 58. Cephalometric Applications procedure
  59. 59. Cephalometric Applications Video imaging Images can include left or right lateral, frontal full face, standard intraoral, or dental casts. These can be viewed on the monitor singly or in traditional groupings (Fig. 14).
  60. 60. Cephalometric Applications Procedure
  61. 61. Cephalometric Applications Digitizing is done in this order: 1) facial landmarks, 2) mouth-closed intraoral landmarks, and 3) intraoral landmarks requiring a disposable bite opener to be inserted. There is a fourth category that is not digitized directly: 4) extrapolated landmarks. Such frequently used points as sella, incisor root apices, and anterior nasal spine cannot be measured directly from the patient using the digitizer. Locations of these points are calculated by the program based on the locations of other related landmarks, using specific mathematical algorithms.
  62. 62. Cephalometric Applications If both lateral and frontal data are being recorded, the lateral imaging and digitizing are performed first. Then the patient is removed from the head holder while it is rotated to the frontal position. An experienced operator can perform a lateral or frontal imaging and tracing in approximately two minutes. At this point, the patient is no longer required to be present. The information is ready to be analyzed by the orthodontist.
  63. 63. Cephalometric Applications 4. Cephalometric Analysis Display The program produces any of 14 cephalometric analyses:
  64. 64. Cephalometric Applications •Ricketts lateral • Ricketts frontal • Vari-Simplex • Holdaway • Alabama • Jarabak • Steiner • Downs • Burstone
  65. 65. Cephalometric Applications Additional custom analyses may be set up, using any combination of more than 150 cephalometric measurements programmed into the Work Station. The observed value is shown along with the patient norm— adjusted for age, sex, race, and head size— and standard deviations from the norm.
  66. 66. Cephalometric Applications 5.Tracing Display Tracings - displayed immediately; include planes relevant to the selected cephalometric analysis; An advantage - is that the nonlinear distortion associated with radiographs is eliminated. - all points are recorded in a direct, oneto-one manner, allowing precise superimposition of patient tracings over video images (Fig. 19).
  67. 67. Cephalometric Applications 6. Visual Treatment Objective To move part of the picture, simply touch the light pen to two points on the screen, at opposite extremes of the area to be moved. The computer draws a box with the two points at opposite corners (Fig. 20A). Then, by touching the light pen to another spot on the screen, the boxed image is moved to that spot (Fig. 20B). Boxes can be moved vertically, horizontally, or diagonally, or they can be rotated about any point.
  68. 68. Cephalometric Applications The software automatically blends skin tones and smoothes profile lines so they are consistent with the surrounding tissue. "before and after" format (Fig. 21). The light pen can also be used for freehand drawing over any video image.
  69. 69. Cephalometric Applications 7. Finishing a DigiGraph Session At this point, the operator saves the data onto the two 3 ½ " patient disks . The information on the two disks is identical, but one is a backup. These disks - stored All the information for one patient's treatment usually fits on a 3½" disk.
  70. 70. Teleradiology INTRODUCTION AND DEFINITION Teleradiology is the electronic transmission of radiological images from one location to another for the purposes of interpretation and/or consultation.
  71. 71. Teleradiology When a teleradiology system is used to produce the official authenticated written interpretation,there should not be a significant loss of spatial or contrast resolution from image acquisition through transmission to final image display.
  72. 72. Teleradiology GOALS A. providing consultative and interpretative radiological services in areas of demonstrated need; B. making services of radiologists available in medical facilities without on-site radiologist support; C. providing timely availability of radiological images and radiologic image interpretation in emergent and nonemergent clinical care areas;
  73. 73. Teleradiology GOALS D. enhancing educational opportunities for practicing radiologists; E. promoting efficiency and quality improvement; and Teleradiology is an evolving technology. New goals will continue to emerge.
  74. 74. Teleradiology EQUIPMENT GUIDELINES Equipment guidelines cover two basic categories of teleradiologic systems when used for rendering the official authenticated written interpretation: small matrix size and large matrix size.
  75. 75. Teleradiology A. Specific Guidelines 1. Small-matrix systems (computed tomography (CT), magnetic resonance imaging (MRI), ultrasound, nuclear medicine, and digital fluorography): a. Digitization system: These systems require 0.5k x 0.5k x 8 bits array or better. b. Display System: These systems require a 0.5k x 0.48k x 8 bits array or better.
  76. 76. Teleradiology 2. Large-matrix systems (digitized radiographic films and computed radiography): a. Digitization system: These systems require a 2k x 2k x 12 bits array or better. b. Display system: These systems should be 2k x 2k x 8 bits array or better. .
  77. 77. Teleradiology B. General Guidelines 1. IMAGE MANAGEMENT Teleradiologic require the use of image management for optimal performance. Both matrix systems should include:
  78. 78. Teleradiology a. capability for the selection of the image sequence for transmission and display at the receiving site; b. capabilities for use at the transmitting station that must include patient name, identification number, date and time of examination, institution of origin, type of examination, degree of compression (if any), and brief patient history; and
  79. 79. Teleradiology 2. TRANSMISSION OF IMAGES AND PATIENT DATA New technology systems should include the current version of the ACR image data format standard and the DICOM network standard.
  80. 80. Teleradiology PATIENT DATABASE For radiological images transmitted by teleradiology, a database should be available, at either the transmitting or receiving site, that includes: a. patient name, identification number, and date; b. type of examination; and c. type of images.
  81. 81. Teleradiology SECURITY Teleradiology systems should provide network and software security protocols to protect the confidentiality of the patient images and data.
  82. 82. Teleradiology (USES) 1. Teleradiology allows timely interpretation of radiological images 2. Gives greater access to secondary consultations and to improved continuing education. 3. Users in different locations may simultaneously view images. 4. Appropriately utilized: can improve access to quality radiological interpretations and thus significantly improve patient care.
  83. 83. The introduction of digital image sources in the 1970‘s and the use of computers in processing these images led the American College of Radiology (ACR) and the National Electrical Manufacturers Association (NEMA) to form a joint committee in order to create a standard method for the transmission of medical images and their associated information.
  84. 84. •This committee, formed in 1983, •in 1985 published the ACR-NEMA Standards Publication .. • with the release of version 3.0 a name change - Digital Imaging and Communications in Medicine (DICOM)
  85. 85. The DICOM standard today uses a specific network protocol utilizing TCP/IP created a mechanism for identifying Information Objects as they are acted upon across the network.
  86. 86. • DICOM defined Information Objects not only for images but also for patients, studies, reports, and other data groupings. • With the enhancements made in DICOM (Version 3.0), came the development and expansion of picture archiving and communication systems (PACS) and its interfacing with medical information systems.
  87. 87. DICOM is used or will soon be used by virtually every medical profession that utilizes images within the healthcare industry. These include cardiology, dentistry, endoscopy, mammography, opthamology, orthopedics, pathology, pediatrics, radiation therapy, radiology, surgery, etc. DICOM is even used in veterinary medical imaging applications.
  88. 88. Transmission of images done : •using various forms of Ethernet • virtual private networks (VPNs), • within a metropolitan area (often using ATM), • by modem • and via satellite
  89. 89. DICOM does not specify functional requirements for an entire system, For example, storage of image objects is defined only in terms of what information must be transmitted and retained, not how images are displayed or annotated. DICOM can be considered as a standard for communication across the ―boundaries‖ between heterogeneous applications, devices and systems.
  90. 90. Dentofacial Planner Plus is a powerful treatment visualization software system. DFP Plus links digitized lateral cephalograms to digital facial images - move the skeletal and dental components of the cephalometric tracing - the cephalometric profile and the facial image are automatically transformed to represent the predicted facial form.
  91. 91. Specifications Recommended hardware: Pentium computer, Windows 95, MS-DOS 5.0 or higher 1 GB hard drive, 16 MB RAM (expandable to 32 MB) Tseng ET-4000 graphics adapter Microsoft bus mouse backup system - tape or zip drive 2 serial ports, a parallel port 800 x 600, 1024 x 768 graphics resolution Supported digitizers:
  92. 92. Video Cameras; Recommended features; S-video output, also known as super VHS or Y-C video high pixel count (over 320,000 pixels) charge coupled device (CCD); generally found in Hi-8 cameras through-the-lens (TTL) macro auto-focus for ease of focus when acquiring intraoral images white balance control
  93. 93. Cephalometrics DFP Plus contains all of the cephalometric functionality of Dentofacial Planner, A digitized radiograph is used as the starting point for a wide variety of cephalometric analyses and superimpositions, growth estimation, orthodontic treatment planning and surgical prediction. Soft tissue profile changes are automatically computed and displayed during treatment planning manipulations.
  94. 94. Flexible Cephalometric Analysis DFP and DFP Plus share the unique functionality of Tools(tm), that provides flexibility in customizing the work. Tools - mix and match measurements from several different analyses into one or more personalized cephalometric analyses. easily add new landmarks, measurements and graphical reference lines.
  95. 95. - automated lateral facial image manipulation through linkage to digitized lateral cephalograms. Facial form is automatically transformed in response to interactive hard tissue manipulations: Incisor retraction, advancement Maxillary orthopedics Functional appliance therapy Mandibular auto- or counter-rotation LeFort 1 maxillary surgery Mandibular advancement, setback Total or anterior sub-apical osteotomy Genioplasty
  96. 96. Image Review: • simultaneously showing pretreatment and predicted images: Other functions; •Ceph superimposition and narrow review •Overlay ceph tracing on image •Semi-transparent image superimposition
  97. 97. Cephalometric Hardcopy generate precise cephalometric hardcopy through the use of pen plotters, laser printers or ink-jet printers. Tracing size can be varied so that multiple tracings can be generated per page, in either portrait or landscape orientation.
  98. 98. VISTADENT Image management system VISTADENT COMPLETE™ ability to modify an image that is stored in the program, as well as the ability to do Visual Treatment Objective (VTO). Images can easily be manipulated to show treatment objectives by using standard editing features such as cut and paste or more advanced features like the Smile Library.
  99. 99. VISTADENT Image management system Ideal system requirements;  win 98 operating system or above  pentium processor II 64 MB RAM 1GB hard disk space
  100. 100. Cephalometric Applications Other attachments  digital camera or scanner  RGB camera Printer ( color)  CD ROM drive
  101. 101. VISTADENT Image management system Easy to calculate cephalometric analysis. The Ceph program allows one to trace and identify your points directly from a scanned X-RAY. After points and tracings are entered they can easily be edited for accuracy purposes. Then Tracings, Analysis and Measurements can all be printed on one page with the image.
  102. 102. VISTADENT Image management system The VTO feature automatically illustrates soft tissue changes based on measurements for most orthodontic treatment as well as many surgeries.
  103. 103. Cephalometric Applications Procedure;  input - scanner / digital camera Photographs and x –rays (tracing) are scanned separately  digitizing the ceph - stream mode i) Using a digitizing tablet ii) On screen tracing
  104. 104. Cephalometric Applications  Aligning the ceph on the photograph  Calibration  Ready for use
  105. 105. Arthrography (TMJ)  Radiographic invasive technique  uses a radio opaque substance (Tc99 / Ba )  injected into the joint space to enhance the contrast between disc and the space
  106. 106. Arthrography (TMJ) Equipment required;  dental X ray unit  Syringes ( 27 gauge needle )  L.A.  Contrast medium
  107. 107. Arthography (TMJ) Procedure: 1. Anesthesia;  27 gauge needle with 1ml of 2% lignocaine  Subcutaneously - 5 mm anterior to tragus  Open mouth 1 finger – forward, inward and upward - till contact with posterior lateral aspect of the condyl.  Inject 0.4ml in the lower compartment
  108. 108. Arthrography (TMJ) For the upper compartment;  5 mm superior to the lower compartment insertion site.  The mouth opening should be more
  109. 109. Arthrography (TMJ) Patient Positioning ;
  110. 110. Arthrography (TMJ) Opacifying the Lower joint;  a new 27 gauge needle is used  insert 1cm posterior to the tragus of the ear  Needle is placed on skin overlying the condyl  mouth should be open at this time  0.5 – 1ml injected
  111. 111. Arthrography (TMJ) Opacifying the upper joint;  27 gauge needle is used  insert 5mm superior to insertion of the lower compartment needle  mouth should be open more than halfway  After contacting bone, withdraw 1 -2mm and inject 1- 1.5ml
  112. 112. Arthrography (TMJ) Exposure factors;  65 kVp for speed of 400 (film)  40 degree angle ( tomograph)  Distance of 42‖ from source
  113. 113. Arthrography (TMJ)
  114. 114. Arthrography (TMJ) Post – Op;  contrast media aspirated and the spaces should be irrigated with saline  patient should be informed about the pain and if it remains persistent - medication
  115. 115. Arthrography (TMJ) This procedure is not used now a days because of:  Patient discomfort  allergic reactions  chances of disc perforation  time consuming  relatively high radiation exposure
  116. 116. Arthrography (TMJ) More recent techniques for TMJ imaging 1. Bones - CT Scanning 2. Joint spaces and disc - MRI
  117. 117. Magnetic Resonance Imaging Principles: Magnetism is a dynamic invisible phenomenon consisting of discrete fields of forces. Magnetic fields are caused by moving electrical charges or rotating electric charges. Images generated from protons of the hydrogen nuclei.* Essentially imaging of the water in the tissue. 
  118. 118. Magnetic Resonance Imaging  The technique is based on the presence of specific magnetic properties found within atomic nuclei containing protons and neutrons, Inherent property of rotating about their axis Causes a small magnetic field to be generated around the electrically charged nuclei.
  119. 119. Magnetic Resonance Imaging When dipoles exposed within a strong electric field Orientation in response to the field Depending on density and spatial relation Signal interpreted and image produced
  120. 120. Magnetic Resonance Imaging When images are displayed; intense signals show as white and weak ones as black. Intermediate as shades of gray. Cortical bone and teeth with low presence of hydrogen are poorly imaged and appear black.
  121. 121. Magnetic Resonance Imaging Equipment; 1. The Gantry ;houses the patient. Patient is surrounded by magnetic coils 2. Operating console ; where the operator controls the computer and scanning procedure 3. Computer room network.
  122. 122. Magnetic Resonance Imaging (TMJ) The objectives of MRI imaging of the TMJ are;  Determine relationship between the disc and Temporal and mandibular components of the TMJ  Detect inflammation, hematoma and effusion for the soft tissue components
  123. 123. Magnetic Resonance Imaging (TMJ) MRI clearly differentiates the soft tissue components . Short and long echo imaging of the TMJ enables identification of the positional relationships between the disc and the condyl
  124. 124. Magnetic Resonance Imaging (TMJ) The contrast and appearance of images can be varied by selecting the field strength and other factors. Special head holders have been designed which facilitates orientation of the patient and reduces patient movement during imaging.
  125. 125. Magnetic Resonance Imaging Complications; Magnetic forces and radio waves - not know to produce any biological side effects in man. Non invasive technique and can be used in most patients. 
  126. 126. Magnetic Resonance Imaging     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.*
  127. 127. Magnetic Resonance Imaging       Indications Assessing diseases of the TMJ Cleft lip and palate Tonsillitis and adenoiditis Cysts and infections Tumors
  128. 128. Magnetic Resonance Imaging     Short comings; Inability to identify ligament tears or perforations Dynamics of tissue joint not possible Cannot be used in patients suffering from claustrophobia.
  129. 129. Computed Tomography   Invented by Sir Godfrey Hounsfield who was awarded a Nobel prize in 1979 CT is an image display of the anatomy of a thin slice of the body developed from multiple x- ray absorption measurements made around the body‘s periphery.
  130. 130. Computed Tomography Parts of the Equipment; 1. Scanner ( movable x ray table + gantry) 2. Computer system 3. A display console
  131. 131. Computed Tomography Principle; A x ray source and array of detectors mounted within the gantry rotate around the patient during each scan. Detectors record the attenuation values of the beam emerging from the patient Information from each traverse is a Profile
  132. 132. Computed Tomography The tube and detectors are further angled and another traverse is made. A series of Profiles is built up. The computer analyses the data and an image is produced.
  133. 133. Computed Tomography Early scanners translate and rotate system. Recently developed scanners stationary detectors and x ray tube rotates around the patient both the detectors and x ray tube rotate in synchrony
  134. 134. Computed Tomography Radiation dosage 1.536 rad for a single section 1.8432 rad for multiple sections Estimated dose to the centre of the condyl with CT is 180mR
  135. 135. Computed Tomography (TMJ) CT for the evaluation of the TMJ was introduced by Wegener and colleagues for demonstrating bone abnormalities within the TMJ.
  136. 136. Computed Tomography (TMJ)    Useful in determining changes in bone density Primary imaging method when internal derangement or arthrosis is suspected – clinical diagnosis is not always sufficient. Has advantages when planning treatment or operations on jaws and TMJ diseases and deformities.
  137. 137. Computed Tomography Although CT scans are too expensive and the radiation dose too high to be appropriate for orthodontic applications Certain situations, benefits outweigh the risks
  138. 138. Computed Tomography    In the treatment of certain craniofacial deformities. 2D diagnostic records inadequate. To visualize outcome of certain surgical procedures 3D reconstruction of images and viewing of the final images via Monitor or processed via Milling machines or Stereolithography.
  139. 139. Microcomputed Tomography Principally the same as CT, except that the reconstructed cross sections are confined to a much smaller area. Significantly reduces radiation dosage. Used to measure bone connectivity in all 3 dimensions and even record anisotropy – till now not possible even with histology.
  140. 140. Computerized tooth width analysis  Introduced by Christopher T.C. Ho and Terrence Freer  Named as Ho-Freer Graphical analysis of tooth width Discrepancy (GATWD)  Base line data obtained from pre treatment orthodontic casts 9 percentage ratios relating max teeth to mand. teeth were derived. 
  141. 141. Computerized tooth width analysis     Direct input using digital calipers or manual input using visual basic 3.0 Upto 24 tooth width measurements can be done Caliper used is a Mitutoyo 6‖/ 150mm , with tapered beaks Connected to a Mitutoyo digimatic mini processor IBM compatible computer
  142. 142. Computerized tooth width analysis  1. 2. 3. 4. Advantages: Less time consuming Use of digital calipers reduces errors during transfer of measurements Mathematical calculations done by the computer Eliminates reference to standard value tables
  143. 143. What is Invisalign®? Invisalign® is the invisible way to straighten teeth without braces. uses a series of clear removable aligners to straighten teeth without metal wires or brackets.
  144. 144. Invisalign      co-founded by Zia Chishti and Kelsey Wirth in 1997 Based in Sunnyvale, California.* Align Technology the treatment procedure is handled by the computer technicians in Pakistan - process takes 3 weeks to a month. After approval from the orthodontist, specifications are transmitted to the manufacturing plant in Mexico
  145. 145. Invisalign     Patient gets the first aligner 6 weeks after the 1st visit Most treatments require 20 – 60 aligners worn for 2 weeks each Should be taken off only for eating and brushing
  146. 146. Impressions are made using Polyvinyl Siloxane Impression and bite send along with a detailed treatment plan. advanced imaging technology transforms plaster models into a highly accurate 3-D digital image. A computerized movie called ClinCheck® depicting the movement of teeth from the beginning to the final position is created. Procedure After wearing all of the aligners in the series, customized set of From the approved file, aligners are made from laser scanning to build a these models, sent to the set Invisalign® uses of doctor, and given to the actual models that reflect patient. Pt to wear each each stage aligner for about two www.indiandentalacademy.comof the treatment plan. weeks. Using the Internet, the doctor reviews the ClinCheck file - if necessary, adjustments to the depicted plan are made.
  147. 147. Invisalign Contraindications;  patients with severe malocclusions  All children – growing jaws and erupting teeth too complicated for the computer to model
  148. 148. A comparison of sonically derived and traditional cephalometric values Daniel Langford Hall, Anne-Marie Bollen. Angle Orthodontist 1997 No. 5, 365 - 372: The cephalometric technique is the standard used by orthodontists to assess skeletal, dental, and soft-tissue relationships. However, this technique exposes patients to radiation, preventing orthodontists from taking frequent cephalograms to assess growth and to monitor treatment.
  149. 149. A comparison of sonically derived and traditional cephalometric values Daniel Langford Hall, Anne-Marie Bollen. the Dolphin Imaging Company developed the DigiGraph™, a nonradiographic cephalometric method that uses sound waves and mathematical algorithms But its accuracy as a cephalometric alternative has not been adequately investigated.
  150. 150. A comparison of sonically derived and traditional cephalometric values Daniel Langford Hall, Anne-Marie Bollen. The purpose of this study was to compare the values obtained by traditional cephalometrics with those obtained by the DigiGraph technique,for 30 well-known measurements, and then to assess the repeatability (intraobserver comparison) and reproducibility (interobserver comparison) for both techniques.
  151. 151. A comparison of sonically derived and traditional cephalometric values Daniel Langford Hall, Anne-Marie Bollen.    Materials and methods Patients starting or finishing orthodontic treatment at the University of Washington lateral cephalogram. a DigiGraph analysis was performed for each consenting patient.
  152. 152. A comparison of sonically derived and traditional cephalometric values Daniel Langford Hall, Anne-Marie Bollen.   There were no exclusionary criteria. The sample consisted of 70 patients, 41 males and 29 females, with a mean age of 18.2 years
  153. 153. A comparison of sonically derived and traditional cephalometric values Daniel Langford Hall, Anne-Marie Bollen.        Standard cephalograms were obtained using the following criteria: Anode-to-subject distance of five feet. Subject-to-film distance of five inches. A kVp setting of 78 and a mA setting of 100. Kodak Lanax Regular film with an exposure of 0.1 second. A cephalostat with a light indicator was used to orient the patient‗s head so that Frankfort horizontal was parallel to the ground. A dodger was used to enhance the soft tissue profile.
  154. 154. A comparison of sonically derived and traditional cephalometric values Daniel Langford Hall, Anne-Marie Bollen.     The patients closed their teeth together (centric occlusion) and relaxed their lips to provide the most correct reproduction of lip morphology. The lateral cephalograms were traced by hand on acetate paper using a mechanical pencil with a 0.5 mm diameter lead. Landmarks were identified for each cephalogram, and 30 angular and linear measurements were calculated by hand, using a protractor and millimeter ruler. Measurements were made to the nearest 0.5 mm or degree.
  155. 155. A comparison of sonically derived and traditional cephalometric values Daniel Langford Hall, Anne-Marie Bollen.  Each subject was digitized in the manner described in the DigiGraph operations manual.
  156. 156. A comparison of sonically derived and traditional cephalometric values Daniel Langford Hall, Anne-Marie Bollen.    Patients were asked to bring their teeth together (centric occlusion) and to relax their lips. The appropriate landmarks were digitized in the following order: (1) facial landmarks, (2) mouth-closed intraoral landmarks, and (3) mouth-open intraoral landmarks. The fourth category of landmarks cannot be digitized directly (e.g., sella turcica) and are computed by mathematical algorithms. The desired analysis (e.g., Steiner, Downs) was selected and the linear and angular measurements were computed by the DigiGraph system. The average time to digitize a patient once was approximately 10 minutes.
  157. 157. A comparison of sonically derived and traditional cephalometric values   Daniel Langford Hall, Anne-Marie Bollen. To assess the intraobserver error, 15 randomly selected subjects were immediately digitized a second time by the primary examiner. The corresponding cephalograms were traced a second time after a 2week interval. To assess interobserver error, 15 subjects were chosen at random, and immediately following the initial procedure, a second examiner, independently digitized the patients. The second examiner also independently traced the corresponding cephalograms.
  158. 158. A comparison of sonically derived and traditional cephalometric values Daniel Langford Hall, Anne-Marie Bollen.    Results Differences in techniques The means, mean differences, and standard deviations of the differences for the two techniques are listed in Table 1.
  159. 159. There was a statistically significant mean difference for 18 of the 30 measurements (p >.0067).  Eighteen of the measurements had standard deviations equal to or greater than +/- 4.0 degrees/millimeters.
  160. 160. A comparison of sonically derived and traditional cephalometric values Daniel Langford Hall, Anne-Marie Bollen.   Correlation of methods Correlation coefficients between both methods were calculated (Table 1). Twenty-eight of the 30 variables had statistically significant correlation coefficients (r> .37), but only four had correlation coefficients greater than 0.80.
  161. 161. A comparison of sonically derived and traditional cephalometric values Daniel Langford Hall, Anne-Marie Bollen.     Repeatability / Reproducibility the DigiGraph angular and linear mean error values were two to three times that of the cephalogram mean error values. For both angular and linear measurements, the interobserver error for the two methods was greater than the intraobserver error. For all the intraobserver measurements, there was greater agreement for the traditional cephalometric values than for the DigiGraph values. Except for Steiner's soft-tissue convexity, interoperator measurements for the cephalogram show greater reproducibility.
  162. 162.
  163. 163. A comparison of sonically derived and traditional cephalometric values Daniel Langford Hall, Anne-Marie Bollen.   Discussion; Sixty percent of the variables had mean differences between methods that were statistically significant. The greatest differences were found for the measurements involving sella, orbitale, A-point, and incisor position.
  164. 164. A comparison of sonically derived and traditional cephalometric values Daniel Langford Hall, Anne-Marie Bollen.  Measurements relying on soft-tissue landmarks, which were digitized directly, showed no difference between techniques.
  165. 165. A comparison of sonically derived and traditional cephalometric values Daniel Langford Hall, Anne-Marie Bollen.  The sonically generated values consistently showed less agreement between examiners.  -while two consecutive digitizations were taken for each patient, only one cephalogram was taken. - a single cephalogram was traced twice.
  166. 166. A comparison of sonically derived and traditional cephalometric values   Daniel Langford Hall, Anne-Marie Bollen. patients were asked to remain in the DigiGraph head positioner between digitizations. - a head-holder can minimize movement but cannot prevent it superficial skeletal landmarks such as orbitale are not digitized directly, but necessitate palpation and firm pressure.- not being able to directly visualize a landmark increases the likelihood of identification error.
  167. 167. A comparison of sonically derived and traditional cephalometric values Daniel Langford Hall, Anne-Marie Bollen.  deep skeletal structures, such as sella turcica and the root apices, are derived from mathematical algorithms, which can only estimate the position of the true landmark.  only the subject's right-sided structures are digitized, any asymmetry that is projected on the cephalogram will not be represented by the DigiGraph.
  168. 168. A comparison of sonically derived and traditional cephalometric values Daniel Langford Hall, Anne-Marie Bollen.  The concept of a nonradiographic technique to perform cephalometric analyses is encouraging, but the diagnostic information must be comparable to the traditional technique  If a three-dimensional analysis can be developed based on landmarks that can be digitized directly, perhaps the DigiGraph can be an adjunct to the lateral cephalogram.
  169. 169. A comparison of sonically derived and traditional cephalometric values Daniel Langford Hall, Anne-Marie Bollen. Conclusions 1. Eighteen of 30 sonically generated measurements were statistically different from the radiographically generated measurements; however, the differences for some measurements may not be clinically significant. The soft tissue variables revealed no significant difference between the two techniques. 2. The regression analyses showed low correlations for all measurements except lower incisor to NB (mm), Ricketts' esthetic line, and Steiner‗s soft tissue convexity.
  170. 170. A comparison of sonically derived and traditional cephalometric values Daniel Langford Hall, Anne-Marie Bollen. 3. Intraobserver and interobserver errors were found with both techniques, but overall repeatability and reproducibility were greater for the radiographically generated measurements. 4. The DigiGraph's soft tissue measurements involving landmarks that were digitized directly were comparable to those obtained by the radiographic cephalometric analysis.
  171. 171. Arthroscopy First arthroscopic examination of the TMJ reported by Ohnishi in 1975 Invasive technique One of the several diagnostic methods and not a substitute for a thorough case history, clinical examination and indirect imaging.
  172. 172. Arthroscopy Indications; 1. Internal derangements 2. Osteoarthrosis 3. Examination and biopsy of suspected neoplastic disease and 4. Investigation of post traumatic complains
  173. 173. Arthroscopy Equipment; 1. Small diameter arthroscope (needlescope) 2. Sharp and blunt trocars 3. Arthoroscopic sheath 4. Fiber optic cable 5. Light source 6. Video documentation sets
  174. 174. Arthroscopy Anesthesia frequently done under G.A – diagnostic arthroscopy may be done under LA  Auriculotemporal nerve is blocked, posterior to the condylar neck.
  175. 175. Arthroscopy Technique;  Patient asked to open mouth  Joint space distended by injection of isotonic saline in to joint space  3ml for upper compartment and 1.5 for lower compartment
  176. 176. Arthroscopy     3mm vertical skin incision made at the injection site using a sharp trocar surrounded by the arthroscopic sheath The lateral capsule is punctured Resistance felt as the capsule is penetrated Sharp trocar is exchanged for a blunt one
  177. 177. Arthroscopy      Trocar pushed further Then exchanged for an arthroscope 2nd puncture created on the canthaltragal line 5mm ant. And 3mm inferior the arthroscope sheath A 2mm diameter cannula is inserted . Joint continuously irrigated during the procedure with saline or Ringer‘s solution.
  178. 178. Arthroscopy Provides valuable data that cannot be obtained by other methods – direct visualization. Shows a high diagnostic accuracy and low risk of postoperative complications
  179. 179. Thank you For more details please visit