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Occlusograms

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Occlusograms

  1. 1. OCCLUSOGRAMS www.indiandentalacademy. com
  2. 2. Orthodontist works primarily in the occlusal plane of space. Advent of radiographic cephalometrics have planned the treatment modality in two dimension space, INTRODUCTION www.indiandentalacademy. com
  3. 3. Currently, the lateral cephalometric head films is used in many respects to the exclusion of record that define the third dimension. www.indiandentalacademy. com
  4. 4. Burstone (1961) introduced a new procedure called occlusogram (positive print 1:1 photographs) and with the help of lateral cephalometric head films it is now possible to make treatment plan in all 3 dimension. “An occlusogram is a 1:1 reproduction of the occlusal surfaces of plaster models on a sheet of acetate tracing paper.” www.indiandentalacademy. com
  5. 5. Photographic technique - Introduced by Burstone; 1961, producing positive - print 1:1 photography of dental casts and tracing was done with the help of photograph. Photocopier technique - Introduced by Yen. Photocopy of models are taken and then they are traced and digitized. TYPES OF OCCLUSOGRAMS www.indiandentalacademy. com
  6. 6. Manual eye viewer technique – Introduced by White, describes a device called an occlusal tracer, which makes a tracing of the teeth directly from the model. (JCO, Feb 1982) Computerized occlusogram - Introduced by Burstone, 1:1 photograph is taken and scanned on to which the points are digitized. (JCO, August 1979) Cont… www.indiandentalacademy. com
  7. 7. • Individualized Arch Forms: The occlusal shape of each tooth can then be traced in an ideal position on this basic arch, and a customized ideal lower arch form can be constructed and used throughout treatment. USES OF OCCLUSOGRAMS White: JCO, Feb 1982 www.indiandentalacademy. com
  8. 8.  Arch Length Discrepancy Measurement: The occlusogram also permits the clinician to make highly accurate and reliable arch length discrepancy measurements by superimposing the idealized lower arch form on the original. Cont…. www.indiandentalacademy. com
  9. 9.  Occlusal Simulations: Marcotte and Burstone suggested setting the maxillary teeth around an idealized lower arch form so that it would be possible to do an occlusal simulation, or what is known as a "set-up": without the time and inaccuracies inherent in a plaster model technique. Occlusal simulations permit the orthodontist to quickly see if the maxillary teeth even have the possibility of occluding with the lower correctly. Cont… www.indiandentalacademy. com
  10. 10.  Evaluation of Various Treatment Plans: The orthodontist can try any alternative he can think of without risk or harm to the patient. Once a decision is made regarding the diagnosis and treatment plan, the orthodontist can implement this plan with a high level of confidence. Cont… www.indiandentalacademy. com
  11. 11.  To compare malocclusions with occlusogram norms.  To formulate accurate tooth-size discrepancies. Many clinicians prefer using diagnostic model setups of standard Bolton measurements, but setups are time consuming and difficult to master. Occlusogram set up gives accurate tooth size discrepancy. Occlusograms Revisited JCO, July 1992 www.indiandentalacademy. com
  12. 12.  To construct ideal and individualized arch forms. Nature arranges teeth in arcs through various forces. An ideal arch selected at the beginning can provide a template for arch wire construction throughout treatment. These arch wire patterns bring a coherence and consistency to arch wire construction that is difficult to achieve by any other means. Cont… www.indiandentalacademy. com
  13. 13.  To create occlusal simulations.  To evaluate various treatment plans.  To make accurate measurements of arch length discrepancy (ALD). Cont… www.indiandentalacademy. com
  14. 14. OCCLUSOGRAM NORMS (WHITE JCO-1982) Although occlusograms have been used by a few orthodontists for several years, there have been no published norms or guidelines. Marcotte published an excellent paper regarding the clinical significance of occlusograms in 1976. In 1978, White illustrated how occlusograms could be used for arch form determination and arch length discrepancy measurements. www.indiandentalacademy. com
  15. 15. Occlusograms of twenty-four untreated normal adult Class I occlusions were made at the University of Connecticut using Dr. Burstone's photographic technique. The measurements on this sample of occlusograms leads to some suggested guidelines for those who want to use occlusograms. www.indiandentalacademy. com
  16. 16.  Each upper tooth touches two lower teeth below it, with the exception of the last upper molar, which has only the last lower molar to bite against.  The biting edge of the upper anterior teeth lies in front of the biting edge of the lower anterior teeth by an average of .7mm (anterior overjet).  The upper posterior teeth extend beyond the lower posterior teeth by an average of 2.3mm on each side (posterior overjet). www.indiandentalacademy. com
  17. 17. Typical ideal normal Class I occlusogram. www.indiandentalacademy. com
  18. 18.  The upper bicuspids are wider than the lower bicuspids by an average of 1.9mm on each side (bicuspid lateral overjet).  The upper molars are wider than the lower molars by an average of 1.4mm on each side (lateral molar overjet). www.indiandentalacademy. com
  19. 19.  A key to firm static occlusion is the width and position of the maxillary lateral incisors. If these teeth are positioned correctly, they will extend at least to the middle of the mandibular cuspid. This will insure that the maxillary cuspid will be in proper occlusal position, contacting the lower first bicuspid. If the maxillary incisors are not wide enough to permit the lateral incisors to engage the mandibular cuspids properly, it will be impossible to achieve a firm Class I occlusion without spacing between the upper anterior teeth. www.indiandentalacademy. com
  20. 20. TYPES OF ARCH FORMS JCO-Nov 1978: White There are four currently popular formulae for arch shape determination: • Bonwill-Hawley formula, • Brader arch forms, • The Catenary arch design, and • Rocky Mountain Data Systems computer-derived formula. www.indiandentalacademy. com
  21. 21. Bonwill-Hawley Arch Design: • Based upon the combined mesiodistal widths of the incisors and cuspids. • Arc of the anterior teeth relates an equilateral triangle. • Largely been discredited, but it is still widely used. • The shape of an ideal arch wire from an orthodontic supply company will most likely be of the Bonwill-Hawley design. www.indiandentalacademy. com
  22. 22. Bonwill-Hawley Arch Design:Bonwill-Hawley Arch Design: www.indiandentalacademy. com
  23. 23. Brader Arch Design: • Known as trifocal ellipses. • Based on arch width at the second molars as measured at the facial, gingival surface. • Brader arch adapts to the facial surfaces of the teeth and all of the forms are alike in shape. They differ in size as dictated by the widths at the second molars. www.indiandentalacademy. com
  24. 24. Brader Arch Design www.indiandentalacademy. com
  25. 25.  The maxillary arch form is always one size larger than the mandibular and coordination of working archwires throughout treatment is greatly simplified.  The main clinical criticism of the Brader arches is that when those forms are followed, there is often severe narrowing in the cuspid areas . Cont… www.indiandentalacademy. com
  26. 26. Typical narrowing of cuspids treated with Brader arch forms. www.indiandentalacademy. com
  27. 27. Catenary Arch Design: • Determined by intermolar widths, but measured from central fossa to central fossa. • Curve which results when a fine chain is suspended at its two ends. • Described as a central core or central perimeter around which the teeth arrange themselves. • Catenary's popularity is the work of MacConaill and Scher. www.indiandentalacademy. com
  28. 28. Catenary Arch Design: www.indiandentalacademy. com
  29. 29. Cont… • MacConaill and Scher acknowledge some deviations from this "pure form", but suggest that these are due to pathological forces that occur during eruption of the teeth and subsequent alveolar development. • Burdie and LillieH found that a basic bony arch is established as early as 9.5 weeks in utero and they suggested that this basic arch was of a catenary design. However, their own evidence shows many arches which were arranged outside of the catenary form and certainly this is before any pathological force has disturbed the catenary "pure form ". www.indiandentalacademy. com
  30. 30. • RMDS is based upon measurements taken from intermolar width, intercuspid width, and arch depth as measured from the facial surface of the incisor to the distal surface of the terminal molar. • This allows the computer to be programmed with Cartesian x and y coordinates that are necessary for a two-dimensional, computer-derived formula. Facial type is also considered in this arch computation. Computer-derived archDesign www.indiandentalacademy. com
  31. 31. Computer-derived archDesign www.indiandentalacademy. com
  32. 32. All of these techniques have one common area of agreement, the anterior part of the dental arch is part of a curve. This curve has been described as 1. an ellipse, 2. a parabola, 3. part of a trifocal ellipse, 4. and a catenary. www.indiandentalacademy. com
  33. 33. A study was undertaken to see how a collection of ideal, untreated arches conformed to the predetermined arch forms of the most popular formulae, and to come to conclusions, if possible, about how reasonable, ideal arch forms can be derived for individual patients. www.indiandentalacademy. com
  34. 34. Dental casts of twenty-four orthodontically untreated, superior, adult occlusions were collected. Tracings of the teeth were made on acetate paper and overlays were constructed and superimposed. RMDS recognized the possibility of arch asymmetry and changed its computer analysis method to use a different mathematical curve for each side of the asymmetric patient. www.indiandentalacademy. com
  35. 35. Clinical Technique Determining Physiologic Archforms – Oakes method (JCO,Feb1991) Mandibular model with all permanent teeth present provides the best basis for construction of a correct or "physiologic" arch form. This technique takes less than three minutes. For the best symmetry, trace first from the midline to the left, then flip the acetate over and trace from the midline to the left on the opposite side. www.indiandentalacademy. com
  36. 36. 1. Attach cake-decorating beads, representing the ideal bracket positions, to the mandibular model with toothpaste. www.indiandentalacademy. com
  37. 37. 2. Place a clear piece of glass or plastic over the model, or place the model in an occlusogram jig and overlay the jig with acetate. www.indiandentalacademy. com
  38. 38. 3. Viewing the model from directly overhead, transfer the bead positions to the acetate, glass, or plastic with a permanent marker. www.indiandentalacademy. com
  39. 39. 4. Remove the acetate, glass, or plastic from the model, and connect the dots as symmetrically as possible. Some smoothing is often needed to obtain symmetry in cases with anterior crowding. www.indiandentalacademy. com
  40. 40. Place the lower arch wire directly over the traced arch form. Bend the upper arch wire to lie outside the traced arch form. Physiologic archforms are difficult to construct in cases where there is severe intercanine constriction. If the original intercanine width is maintained, the arch form will be "squeezed" in the cuspid region. Although the principle is sound, such an arch form would be unacceptable. In these cases, expansion is necessary and extended retainer wear must be encouraged. www.indiandentalacademy. com
  41. 41.  Although preformed arches have been made using various geometric or computer-generated data, the fit to an individual mandibular model is highly variable.  The simple technique described above produces individualized physiologic archforms that reduce the potential for relapse of orthodontic expansion. www.indiandentalacademy. com
  42. 42. • Photographic Technique:  The dental impressions are made, casts poured.  Wax jaw registration be made in centric relation.  This wax centric relation registration is then placed between the dental casts while the posterior borders of the casts are trimmed and made flush with each other. TYPES OF OCCLUSOGRAMS www.indiandentalacademy. com
  43. 43. Study model set-up, Black-and-white camera on horizontal photo copy stand, with lights. www.indiandentalacademy. com
  44. 44.  A registration groove is placed in the backs of both casts simultaneously by means of a custom- made dental cast scriber.  The casts have thus been trimmed with their backs mutually perpendicular to the occlusal plane and to the palatal midline and have also been scribed to permit the positive-print, occlusograms to be oriented laterally.  The casts are then finished and polished in the usual manner. www.indiandentalacademy. com
  45. 45. Central groove cut into the backs of models. Triangular file used to cut central orientation groove. www.indiandentalacademy. com
  46. 46.  Occlusogram camera assembly consists of a 4 by 5 inch box camera, a dental cast stage, two 375- watt floodlights, and a hinged Plexiglas plate.  The camera is mounted on a sliding track, so that the distance from the edge of the stage can be adjusted and fixed to produce a 1:1 magnification. For this particular installation a 210 mm lens is found to be satisfactory.  The dental cast stage has an adjustable guide onto which fit the registration grooves on the backs of the dental casts. www.indiandentalacademy. com
  47. 47. Occlusogram set up. This set up can produce archival-quality occlusograms on positive print film. www.indiandentalacademy. com
  48. 48. Lower dental cast on the registration track of the occlusostat. The registration lines can be seen on the leading face of the occlusostat. The occlusal surfaces of the cast have also been made flush with the leading edge of the occlusostat. www.indiandentalacademy. com
  49. 49. Registration dots which are located in the leading edge of the stage will also be recorded on the occlusogram. With a fine-grain positive film placed into film cassette and with both flood lights focused on the dental casts, a typical the exposure is made. Processed according to manufacturer's directions, maxillary and mandibular occlusograms are produced at 1:1 magnification. www.indiandentalacademy. com
  50. 50.  Using the registration dots on the leading edge of the stage as reference points, both occlusograms are registered on these dots and permanently fixed at the bottom edge with a noncracking type of tape (for example, Mylar tape).  Since the positive print film is transparent, the existing occlusal relationships in centric relation can be seen when the occlusograms are folded over. For most treatment procedures, however, an occlusogram tracing is required. www.indiandentalacademy. com
  51. 51.  For this occlusogram tracing, acetate paper is placed over the occlusograms and the maxillary and mandibular teeth are outlined, showing the gingival tooth contours, incisal edges, buccal cusp ridges, central grooves, and cusp tips.  Also traced are the palatal rugae, the midpalatal raphe, the fovea palatinus, and the registration dots. www.indiandentalacademy. com
  52. 52. Occlusogram tracing Upper and lower occlusogram tracings. Both are shown with the registration dots on the backs and the registration lines (R). A mid saggital reference line is also drawn on the upper occlusogram tracing www.indiandentalacademy. com
  53. 53. Both the occlusogram tracing are assembled on the registration dots. www.indiandentalacademy. com
  54. 54. Photocopier technique • Yen makes a photocopy of the model and then traces or digitizes the photocopy. • Yen's method is easier than the other two, but the photocopying can introduce varying degrees of distortion because the models are three-dimensional. • This distortion can be limited to about 1 -2 percent enlargement if the models are placed on the surface of the machine so that the least amount of shadow is projected to the copy. www.indiandentalacademy. com
  55. 55. Photo copier method www.indiandentalacademy. com
  56. 56. Photocopy of upper and lower models, with right, left, and midline reference marks. www.indiandentalacademy. com
  57. 57. The following is a simple clinical method of using occlusograms to evaluate space requirements, while taking into account lateral and frontal treatment planning objectives. Like Yen's technique, it uses a photocopier, but the effect of a small amount of photocopier distortion is minimized by the measurement procedures. Occlusograms in Orthodontic Treatment Planning FABER; JCO Jul 1992 www.indiandentalacademy. com
  58. 58. Technique:  Make a set of orthodontic study models with a centric relation wax bite registration.  Trim the backs of the models with the bite registration in place, so that when they are placed on their backs they are in centric relation. www.indiandentalacademy. com
  59. 59.  Make three marks on each model with the backs in centric relation and the teeth in occlusion- on the right and left sides in the buccal segments (usually the molars) and at the midline.  Then, extend the marks over the occlusal surfaces so they will appear on the photocopy. Triangular file used to cut central orientation groove. www.indiandentalacademy. com
  60. 60.  Make a photocopy of the models. Photocopy of upper and lower models, with right, left, and midline reference marks. www.indiandentalacademy. com
  61. 61.  Trace both arches along with the reference marks. Mark the right and left sides.  With the frontal cephalogram and the clinical examination, establish the post-treatment midline for the mandibular arch and mark it with an arrow on the lower occlusal tracing. www.indiandentalacademy. com
  62. 62. A. Pretreatment lateral tracing showing AB to occlusal plane. B. Pretreatment anteroposterior tracing with apical base midlines marked. www.indiandentalacademy. com
  63. 63.  Use an arch symmetry chart to establish symmetry of the lower arch from right to left. Mark the midline and a perpendicular reference line. Lower occlusal tracing placed over arch symmetry chart to establish midline and perpendicular reference crosshairs. www.indiandentalacademy. com
  64. 64.  Place the upper tracing over the lower, aligning the reference marks marked on the occlusal surfaces. Transfer the crosshair reference lines from the lower occlusogram to the upper. www.indiandentalacademy. com
  65. 65. Determine the desired post-treatment position of the lower incisor on the lateral cephalometric tracing. Measure the amount of facial or lingual movement, and mark this amount along the vertical reference line on the lower occlusogram. Mark the desired post-treatment cuspid width on the lower occlusogram. www.indiandentalacademy. com
  66. 66. Treatment objectives for incicors and molars. Pretreatment lateral cephalogram www.indiandentalacademy. com
  67. 67.  When the anteroposterior position of the denture bases is influenced by growth, facial growth rotations, changes in the cant of the occlusal plane, and/or surgery, these positions should be anticipated for the period of treatment and incorporated into the occlusogram tracings. www.indiandentalacademy. com
  68. 68. Treatment objectives for orthodontic phase (blue) and surgical advancement of mandible (red).  The amount of movement is calculated by measuring the projected AB to occlusal plane before and after changes. www.indiandentalacademy. com
  69. 69. Completed occlusograms showing archforms in red and space requirements in blue. Dashed line indicates projected change in AB to occlusal plane after surgery.  This can be marked on the occlusogram, and the lower tracing can then be slid forward to the new line to evaluate the arch width required for good posterior occlusion after changes. www.indiandentalacademy. com
  70. 70.  Determine the desired molar movement from the axial inclinations on the frontal cephalogram, from the study models, or from clinical examination of the buccal and gingival tooth contacts.  Mark the desired molar width on the lower occlusogram.  Using a French curve (or a template if desired), draw the treatment-planning archform by connecting the incisor, cuspid, and molar reference points. www.indiandentalacademy. com
  71. 71.  Place the upper occlusal tracing over the lower by aligning the reference crosshairs, and draw the planned upper archform, allowing for buccal and incisal overjet.  Measure the mesiodistal tooth widths directly from the models with bow calipers, then mark off these widths on the occlusogram archforms.  Work distally from the midline, and be sure to measure the widths on both sides of the arch; there are often significant tooth-size differentials from right to left. www.indiandentalacademy. com
  72. 72. Direct measurement of models using bow calipers. www.indiandentalacademy. com
  73. 73. Planned archforms drawn in red, and mesiodistal tooth widths marked off in blue. Blue posterior lines perpendicular to archforms show space required to meet treatment objectives. www.indiandentalacademy. com
  74. 74. This technique demonstrates the versatility and simplicity of occlusograms when used for space analysis and coordination with treatment planning in the other planes of space. www.indiandentalacademy. com
  75. 75. Reliability of Measurements from Photocopies of Study Models:- MICHEL JCO,1992 Oct  Ten sets of study models (20 occlusal surfaces) were photocopied on a Canon PC-25 photocopier.  Each model and its photocopy were then measured by the same operator, using an electronic digital caliper. The following measurements were recorded: 1. Total arch length (the sum of all maxillary and mandibular individual tooth widths) 2. Intercuspid width 3. Intermolar width www.indiandentalacademy. com
  76. 76. Results: There was little difference between the actual models and the photocopies in measurements of arch width. However, there was a substantial difference in the measurements of total arch length. www.indiandentalacademy. com
  77. 77. Photocopies of models appear to be valid for:  Comparing pre- and post-treatment archforms  Checking original tooth rotations or the initial arch form during treatment.  Producing occlusograms for demonstration purposes Photocopies may be less precise for:  Measuring arch length  Producing occlusograms for space analysis www.indiandentalacademy. com
  78. 78. The most primitive technique for making accurate 1:1 occlusal reproductions is to trace the occlusal surfaces of the teeth onto a clear 1/8" plastic sheet that is secured against the dental cast. Since the eye of the viewer is the camera, the viewer's head must not be moved while tracing both sides of the model. With a minimum of practice, highly accurate tracings can be made with inexpensive materials . Manual eye viewer –occlusogram www.indiandentalacademy. com
  79. 79. Manual method: Occlusal map maker. www.indiandentalacademy. com
  80. 80. Computer-Aided Space Analysis YEN- JCO, Apr 1991  Make a photocopy of the upper and lower study models.  Digitize the key landmarks from the photocopy. (If necessary, allow for any enlargement introduced by the photocopier.)  Run the program and print out the data. www.indiandentalacademy. com
  81. 81. Printout of space analysis and computer-generated arch form. Horizontal lines in arch form indicate arch widths. www.indiandentalacademy. com
  82. 82.  Computerized arch form is made by simply connecting the most mesial and distal points of each tooth from second molar to second molar.  Each arch is divided into three segments- anterior (B + C) and posterior (A and D).  The "required space" for each segment is the sum of the tooth sizes in that segment; the "available space" is the total width of the segment. www.indiandentalacademy. com
  83. 83. Each arch is divided into anterior (B + C) and posterior (A + D) segments for space analysis. Computer produces arch form by connecting most mesial and distal points of teeth. www.indiandentalacademy. com
  84. 84. Computerized occlusogram (Burstone -Jco-1979) Digitizing the points of the 1:1 occlusal photograph of the model give the both measurements and a diagram of the tooth positions . The computer does a setup. Points are digitized at the mesial and distal contacts and the tips of the buccal cusps of the lower, and the functional cusps on the upper will be the tips of the lingual cusps. The computer draws the teeth. www.indiandentalacademy. com
  85. 85. Digitizing points on a 1:1 occlusal photograph. Occlusogram. Computer-drawn original and final arch forms. Arch length inadequacies and movement required of each tooth are calculated and shown. www.indiandentalacademy. com
  86. 86. The computer calculates the variations from the mean in tooth size. The reason for seeing this on the screen at this time is to find out if there are major tooth size differences and make a decision on extraction, or to point out a mistake in digitizing. www.indiandentalacademy. com
  87. 87. Now, the first question the computer asks is if the right molar should be moved so that we can determine the geometric midline. There are other determinants of the midline, including what looks good for the face and also if there is any skeletal discrepancy anteriorly. The geometric midline is a point right in the center of the arch if we like the relative positions of the posterior teeth on the right and left sides. www.indiandentalacademy. com
  88. 88. So, the computer asks whether the buccal segments to be moved back in respect to the other, just to equalize their axial inclination or their position. It will then calculate where the center of the arch is — the geometric midline. www.indiandentalacademy. com
  89. 89. Now the computer will first of all draw the original malocclusion on which you see certain control points which the orthodontist decides. Orthodontist decides what the width should be. He digitizes where he wants the lower incisor to be. This is all individualized. All the computer does is make it easy to handle. www.indiandentalacademy. com
  90. 90. Final upper occlusal plot. Now, we have the new arch form constructed. Both the original and final arches are shown on the screen. www.indiandentalacademy. com
  91. 91. The anterior part of the arch is a segment of a parabola, so it fits a parabola between the points that clinician select. There are enough control points, so that each arch form is individualized for the patient. The clinician decides where to position the midline, the computer stores that decision and it then calculates the arch length inadequacy. Also, the computer graphically shows where each tooth will be in the individualized arch. www.indiandentalacademy. com
  92. 92. Control points are placed one in the midline point, how far backward or forward you want the incisor. Clinician also selects the width points where he thinks the tips of the cuspids should be, and the mesiobuccal cusp of the first and second molars. The clinician must make those decisions. No computer can make them. However, lateral treatment planning program helps with the decision of where the lower incisor goes. www.indiandentalacademy. com
  93. 93. Now, the computer asks if he want to see a hard copy. Normally hard copies are made as a permanent record at the end. The printout is three times life size, so he can see what the relationships are in detail. The longer lines represent the mesials of the first molars . www.indiandentalacademy. com
  94. 94. Computerized setup. Lower teeth (red) and upper teeth (green). www.indiandentalacademy. com
  95. 95. Orthodontist can choose to extract and see the "treated case" on the screen. If he doesn't like the results, he can go back and go through another treatment plot. He can try one with different extractions or nonextraction options. A number of different treatment plans can be tried to arrive at the best possible one. www.indiandentalacademy. com
  96. 96. Manual and computer-aided space analysis: A comparative study. Schirmer, AJO;1997 Dec The computer-aided measuring system is reliable, but accurate mesiodistal measurements cannot be made from photocopies of dental models. Manual measurements that use a calibrated gauge produce the most accurate, reliable, and reproducible results. www.indiandentalacademy. com
  97. 97. Video Printing in Orthodontic Photography. BURKE: JCO; Feb 1987 The Mitsubishi P5OU Video Printer measures about 4"×8"×14“. Video printer used to image study models, with sample print.. www.indiandentalacademy. com
  98. 98.  The printer can “ grab” a still picture of anything that appears on the TV monitor when the “ print” button is pushed. This triggering can be done at the printer or by a remote-control extension cord switch.  Video cameras or color camcorder, which has self-contained playback capability, can be connected directly to the video printer for making extraoral pictures. www.indiandentalacademy. com
  99. 99. Close-up lenses are more adaptable. These optical glass “ magnifiers” come in various diopter strengths and attach to the lens. Close-up lenses permit any type of magnification— for example, a 1:1 ratio for occlusograms. Diopter lenses attach to camera lens for close-up focusing.www.indiandentalacademy. com
  100. 100.  Creating a video print is essentially the same as conventional photography, with the added advantage of immediate results for appraisal and adjustment.  Facial images can be improved by using adjustable photo reflector light stands with standard household bulbs.  When you set up your system, trial and error will determine the correct camera distance, magnification, and lighting. www.indiandentalacademy. com
  101. 101. THE “3-D OCCLUSOGRAM” SOFTWARE AJO, Sep 1999: Foirelli • The 3-D Occlusogram (3-DO) procedure includes 4stages, which are performed by different components of the software: • Image scanning and setting • Occlusal view processing • Lateral cephalometric processing • Occlusogram construction www.indiandentalacademy. com
  102. 102. • The treatment goal can be produced either manually, by means of 3-dimensional scanning equipment, or by means of the software demonstrated above coupled with a common flatbed scanner. • The latter has the advantage that, after a rather short training period, it is more rapid and more precise than the manual method without requiring any special and expensive equipment that the orthodontist does not generally already possess. www.indiandentalacademy. com
  103. 103. www.indiandentalacademy. com
  104. 104. Holograms as substitutes for study casts. Harradine et al: AJO 1990 Aug A hologram not only provides two-dimensional information about an object, as found in photographs, but also depth information. This transforms the image of the object into three dimensions. www.indiandentalacademy. com
  105. 105. Plaster casts are mainstay of clinical orthodontic records since many years but has disadvantages:  Fragile & prone for fracture  Bulky & expensive to store and transport. Need keep for long periods. www.indiandentalacademy. com
  106. 106. Advantages of holograms Schwaninger et al (1977) proposed potential advantages of holograms as a substitute for study casts. Holograms are resistant to damage.  Better suited to transport by post.  Can be stored with patient’s clinical records.  Accurate measurements such as intercanine width can be measured. www.indiandentalacademy. com
  107. 107. Chair sideviewer Holographic camera Hologram www.indiandentalacademy. com
  108. 108. Disadvantages  Significant consideration is the consequence of incorrect occlusion of the models when the holograms are being made.  Once made, a hologram cannot be adjusted as a set of study casts.  Clinically useful holograms are therefore more demanding in terms of clinical and laboratory techniques than are study casts. www.indiandentalacademy. com
  109. 109. In a study by Harradine et al ( 1990 Aug AJO) with four clinicians and 56 patients, three of the clinicians found the holograms to be acceptable alternatives to study casts in routine clinical orthodontic practice. Current holographic cameras enable those who are not experts to produce holograms very simply, but careful clinical and laboratory techniques are required to ensure that these holograms correctly record the occlusion. www.indiandentalacademy. com
  110. 110. The Holodent system, a new technique for measurement and storage of dental casts. Martensson et al: AJO 1992 Aug The system has a precision that is equal to that of previously reported methods and may be well-suited for studies of dental positional changes in longitudinal materials of study models. Holograms of dental casts may solve storage problems by replacing space consuming plaster models. www.indiandentalacademy. com
  111. 111. Conclusion Occlusograms offer us an accurate way to measure, compare, and evaluate malocclusions, to plan and forecast treatment, and to visualize occlusal objectives. They do take time, but it can be easily learn how to do them. The use of photocopies removes the need for expensive and arcane equipment. www.indiandentalacademy. com
  112. 112. Hoping that orthodontists will take one more look at this valuable technique. The rewards to both patient and doctor clearly make occlusograms a worthwhile adjunct to our diagnostic armamentarium. www.indiandentalacademy. com
  113. 113. ThankThank youyou www.indiandentalacademy. com

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