Visual treatment objective /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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Visual treatment objective /certified fixed orthodontic courses by Indian dental academy

  1. 1. Visualized Treatment Objective www.indiandentalacademy.com
  2. 2. INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  3. 3.  History of visual treatment objective .  What is the purpose and applicability of VTO ?  Methods of prediction: 1.by templates, 2.by cephalogram  General concepts of VTO  Advantages and disadvantages of VTO  Surgical VTO www.indiandentalacademy.com
  4. 4. History In early days of Orthodontic treatment, the original diagnostic records consisted only of a set of patient record and the patient’s were classified as Angle’s class 1 or 2 or 3 dental malocclusion. Treatment prescription during those times basically aimed at establishing class 1 alignment of the dental arch. Therefore Orthodontics became branded as a field dedicated to correcting occlusal disharmony rather than looking through the facial changes occurring during the course or as a result of the treatment being constituted. www.indiandentalacademy.com
  5. 5. The alignment of the teeth was confined to the upper arch only, as the orthodontist during those times believed that only the upper arch was quite obvious when the patient speaks or smiles. The basic objective to align the teeth was that if the teeth were malaligned, they are more prone to /for decay. As a result growth and treatment forecast terminologies were obsolete during the past. The recognition of jaws interaction and the position of the teeth lead to a refinement of the diagnostic procedure and treatment, wherein beyond dental terminologies all other factors were analyzed. www.indiandentalacademy.com
  6. 6. This recognition occurred after the arrival of cephalometry in 1930’s. Malocclusions were beginning to be classified based on anatomical structure of the jaw. New vistas in orthodontics like computer simulations of the treatment plan wherein the patient is also allowed to make decisions with regards to their own treatment are now on the rise. For a successful treatment to occur, the term prediction was considered as an important criteria. www.indiandentalacademy.com
  7. 7. Prediction       according to Kendall & Buckland – it is the process of forecasting the magnitude of a statistical variant at some point of time in the future.     Baumrind suggested that the prediction of a case assists the Orthodontist psychologically in planning out the treatment process by removing some part of the act & adding a little more science. www.indiandentalacademy.com
  8. 8. Though prediction was considered as an important criteria, the orthodontist faced problems with regards to it due to, a) variations in growth and development b) variations in treatment. www.indiandentalacademy.com
  9. 9. The process of prediction can be performed in 2 ways manually computer (recent trends) www.indiandentalacademy.com
  10. 10. Manual prediction Template prediction:Templates have been shown to be useful in orthodontic diagnosis for comparing cephalometric tracings to established norms. a) In 1952 Baumrind devised a set of 4 templates to be overlaid directly on a x-ray film by using Down’s analysis. b) Grainger & Popovich performed a study on a population in Berlington & devised templates for ages 3-6 yrs & 10-12 yrs that could be used to assess antero-posterior, vertical & lateral facial development. www.indiandentalacademy.com
  11. 11. c) Highley developed cephalometric standards for children 4-8 yrs of age & also proposed sex specific transparencies for each age level. d) Johnston introduced a simplified method of long term forecasting of growth wherein the tracing is superimposed on a printed grid. www.indiandentalacademy.com
  12. 12. The most commonly used cephalometric templates are: • The unisex Bolton templates for ages 1-18. • The Burlington templates, in three basic configurations, for ages 2-18. • The original Burlington templates or the subsequent Michigan modifications. • Jacobson’s proportionate templates for orthognathic surgery and orthodontic cases. • Johnston’s template analysis. www.indiandentalacademy.com
  13. 13. Burlington prediction template www.indiandentalacademy.com
  14. 14. FORECAST GRID L.E. Johnston has produced a diagram on the assumption of regular annual changes and an average direction of the growth. He states that accurate prediction is made in 65% of cases. He developed a simplified method of generating a long term fore cast by use of a printed forecast grid. Each point was advanced on the grid unit per year using a standard S-N orientation registered at S www.indiandentalacademy.com .
  15. 15. Johnston’s prediction grid www.indiandentalacademy.com
  16. 16. Advantages of Template analysis • It provides an immediate picture of the patient’s dentoskeletal structures without any measurements or calculations. • Outlines of hard & soft tissue components can be judged easily. • It allows comparison of the patient’s tracing with an age-appropriate ideal template. • Templates are used based on average of www.indiandentalacademy.com norms from several sources.
  17. 17. In both conventional cephalometric and template analysis, there has long been a need for an absolute reference point or plane from which to measure craniofacial deviations. Many of the common landmarks are sites of bone resorption or deposition and therefore are constantly changing. The relationships of landmarks to one another are also affected by growth and by the orientation of the patient. www.indiandentalacademy.com
  18. 18.   Cephalometric Predicition Cephalometric radiography was once employed primarily to study the growth of the skull, following which it was later recognized as a method for evaluating treated orthodontic cases. Mandibular movements & studies on dynamic occlusion were other phases of its application included later.   Cephalometrics was not popular until they were utilized in routine clinical practice as an aid in diagnosis & treatment planning. www.indiandentalacademy.com
  19. 19. Origin of VTO a) Ricketts in 1960 stated that all treatment planning constituted some type of prediction of craniofacial growth & tooth movement & termed this method of prediction as a Dynamic synthesis. In Ricketts prospective, the VTO is like a blue print used in constructing a house. It’s a visual plan to forecast the normal growth of the patient & the anticipated influences of treatment so as to establish the individual objectives to be achieved for that patient. Treatment for a growing patient according to Ricketts must be planned & directed to the face & structure that can be anticipated in future & not to the skeletal structure that the patient presents initially. www.indiandentalacademy.com
  20. 20. b)  Bench & Hilgers in JCO 1977 state that VTO permits the development of alternative treatment plans. They also state that after setting up the teeth ideally within the anticipated/ grown facial pattern, the orthodontist 1) Must decide how far he must go with mechanics & orthopedics to achieve them. 2) Whether its possible to achieve them 3) What are the other alternatives. www.indiandentalacademy.com
  21. 21. • According to DR. ROTH the dentition can be positioned objectively for esthetics only by doing a VTO. Dr.Reed A Holdaway in 1971 devised the “Visualized treatment objective” a treatment planning method based upon prediction & the desired treatment objectives. The Holdaway VTO emphasizes soft tissue profile balance, whereas other analyses & treatment planning methods reposition the dental structure first thereby permitting the lips to drape over the teeth. www.indiandentalacademy.com
  22. 22. In contrast to Ricketts, Holdaway believed that mandibular incisors could not be rigidly fixed to any anatomical landmarks such as point A to the pogonion line. He proposed that mandibular incisors should be placed relative to their maxillary counterparts where adequate lip support has been established. Growth of the craniofacial skeleton is predicted for the estimated treatment time, and the soft tissue profile between the nose and the chin arranged to create an “ideal” facial profile for the individual patient. Having established the soft tissue profile, the maxillary and mandibular incisor teeth are repositioned to eliminate lip strain. Allowance is made for probable post-treatment “incisor rebound”. www.indiandentalacademy.com
  23. 23. Guidelines are provided whereby the lips are graphically repositioned. A template may be used to facilitate drawing the soft tissue of the lips. This is followed by location of the maxillary incisor teeth. Finally, the lower incisors are repositioned to be in harmony with the upper incisors. Following upon the repositioning of the mandibular incisor, the resultant arch length discrepancy may be calculated to determine whether or not teeth should be extracted prior to orthodontic correction. Should the computed information suggest that teeth be extracted, the V.T.O. will yield information based on anchorage requirements as to whether first or second bicuspids should be removed, or whether the proposed treatment plan is feasible or desirable www.indiandentalacademy.com
  24. 24. Jacobson & Sadowsky in 1980 JCO, state that VTO is a procedure based primarily on cephalometrics, the purpose of which is to establish a balanced profile & pleasing facial esthetics & to evaluate the orthodontic correction necessary to achieve this goal. In attempts to make prediction – Hixon1972 pointed out that the accepted standard error for most of the measurements should not be more than 5 or 6% of the total distance measured, because craniofacial growth is a relatively slow process wherein a small error in constructing the tracing can lead to a significant difference in the results obtained. www.indiandentalacademy.com
  25. 25. Jacobson & Sadowsky JCO 1980 have listed the  advantages the VTO as follows, 1) Predicts growth over an estimated treatment time,       based on the individual   morphogenetic pattern. 2)  Analyzes the soft tissue facial profile. 3)  Graphically plans the best soft tissue facial profile for        the particular patient. 4)  Determines favorable incisor repositioning, based on  an “ideal” projected soft tissue facial profile. www.indiandentalacademy.com
  26. 26. 5.  Assists in determining total arch length discrepancy  when taking into account “cephalometric  correction”. 6. Aids in determining between extraction and non       extraction treatment. 7. Aids in deciding which teeth to extract, if extractions       are indicated. 8. Assists in planning treatment mechanics. 9. Assists in deciding which cases are more suited to       surgical and/or surgical- orthodontic  correction. 10.  It provides a visual goal or objective for which to strive during treatment. www.indiandentalacademy.com
  27. 27. The advantages of the VTO are:           1. Establishment of specific treatment goals                 2.  Formulation of specific treatment plan to reach treatment goals.             3. Assistance in making mid treatment correction             4. Assistance in determining if ideal treatment result is attainable orthodontically / surgically. 5. Enhancing communication between patients and clinicians, 6. Allowing quantification of proposed movements to reduce the difficulties in planning facial response to different movements, 7. Allowing rapid comparisons of different treatment options before arriving at a final treatment plan. www.indiandentalacademy.com
  28. 28. Despite the listed advantages of VTO limitations exist in their implementation. Inadequacies of VTO are 1. Use of average growth increments in growth prediction.   2. Use of existing morphological traits to predict future growth events. 3. Failure of presenting VTO analyses as an exact representation of treatment outcome www.indiandentalacademy.com
  29. 29. Ricketts prediction 1. 2. 3. 4. 5. 6. The cranial base prediction The mandibular growth prediction The maxillary growth prediction The occlusal plane position The location of the dentition The soft tissue of the face www.indiandentalacademy.com
  30. 30. After completion of the different prediction’s, the VTO is taken and superimposed in the five superimposition areas to establish individual objectives for the case. The use of superimposition areas and evaluation areas to establish treatment design including changes due to normal growth and changes due to various treatment mechanics are different for each individual because of his individual morphology and facial type. www.indiandentalacademy.com
  31. 31. In order to forecast effectively and decide upon the correct treatment design, it is necessary for us to first understand the individual patient and describe his basic facial, skeletal and dental structures and secondly we should be able to anticipate normal growth in amount and direction in the various areas of the face and the jaws and thirdly we should understand the response of his individual skeletal and facial structures to various treatment mechanics. www.indiandentalacademy.com
  32. 32. The five superimposition areas used to evaluate the face are in the following order: 1.The chin. 2.The maxilla. 3.The teeth in the mandible. 4.The teeth in the maxilla. 5.The facial profile. www.indiandentalacademy.com
  33. 33. Superimposition Area 1 (Evaluation Area 1) The first superimposition (Basion-Nasion at CC Point) establishes Evaluation Area 1, within which we evaluate the amount of growth of the chin in millimeters; any change in chin in an opening or closing direction that may result from our mechanics; and any change in upper molar. In normal growth, the chin grows down the facial axis and the six year molars also grow down the facial axis. www.indiandentalacademy.com
  34. 34. www.indiandentalacademy.com
  35. 35. Superimposition Area 2 (Evaluation Area 2) The second superimposition area (Basion-Nasion at Nasion) establishes Evaluation Area 2 to show any change in the maxilla (Point A). The Basion-NasionPoint A Angle does not change in normal growth. Therefore, any change in this angle would be due to the effect of the mechanics. With Evaluation Area 2, we can determine whether we wish to use an orthodontic or an orthopedic force on the maxilla with a headgear. www.indiandentalacademy.com
  36. 36. www.indiandentalacademy.com
  37. 37. Superimposition Area 3 (Evaluation Areas 3 and 4) The third superimposition area (Corpus Axis at PM) establishes Evaluation Area 3 and Evaluation Area 4, which together evaluate any changes that take place in the mandibular denture. In normal growth, the lower denture remains constant with the APO Plane (the denture plane). In Evaluation Area 3, we evaluate whether we have to intrude, extrude, advance or retract the lower incisors, which helps us determine what type of utility arch we will use. www.indiandentalacademy.com
  38. 38. In Evaluation Area 4, we evaluate the lower molars to determine what type of anchorage we need and whether we wish to advance, upright or hold the lower molars. www.indiandentalacademy.com
  39. 39. www.indiandentalacademy.com
  40. 40. Superimposition Area 4 (Evaluation Areas 5 and 6) The fourth superimposition area (Palate at ANS) establishes Evaluation Area 5 and Evaluation Area 6, which together evaluate any changes that take place in the maxillary denture. In normal growth, upper molars and upper incisors grow on their polar axis. In Evaluation Area 5, we evaluate what we are going to do with the upper molars— hold, intrude, extrude, distallize or bring them forward. In Evaluation Area 6, we evaluate what we are going to do with the upper incisors— intrude, extrude, retract, advance, torque or tip them. www.indiandentalacademy.com
  41. 41. www.indiandentalacademy.com
  42. 42. Superimposition Area 5 (Evaluation Area 7) The fifth superimposition area (Esthetic Plane at the crossing of the Occlusal Plane) establishes Evaluation Area 7 with which we evaluate the soft tissue profile. In normal growth, the face becomes less protrusive with reference to the esthetic plane. We use Superimposition Area 5 and Evaluation Area 7 to evaluate the effect of our mechanics on the soft tissue of the face. www.indiandentalacademy.com
  43. 43. www.indiandentalacademy.com
  44. 44. VTO by Holdaway www.indiandentalacademy.com
  45. 45. VTO BY HOLDAWAY The main difference between Holdaway’s VTO and other types was that, Holdaway predicted the soft tissue profile first, then the positions of the maxillary incisors. Holdaway re-emphasized the importance of soft tissue analysis as he quantified certain soft tissue relationships in harmonious faces. In contrast to Ricketts, Holdaway believed that the mandibular incisor could not be rigidly fixed to any anatomical landmark such as the Apoint–pogonion line. Instead, the mandibular incisors should be placed relative to the maxillary incisors where adequate lip support had been established. www.indiandentalacademy.com
  46. 46. All cephalometric head films to be taken in the lips closed position even if the lips are strained to close. The various steps involved are, STEP 1. OBJECTIVE: To draw fronto nasal area, line BaN and line NA. Place a clean sheet of acetate paper over the original cephalometric tracing and copy the frontonasal area both hard and soft tissue, tracing through the bridge of the nose. Copy the line BaN. Copy the line NA. www.indiandentalacademy.com
  47. 47. OBJECTIVE I www.indiandentalacademy.com
  48. 48. STEP II OBJECTIVE: To express growth in the frontonasal area over a two-year period. a) Superimpose on line BaN and move the VTO tracing until there is 1.5mm of growth expressed in the frontonasal area b) Holding the VTO tracing in the position as in above, copy the Ricketts facial axis (foramen rotundum to Gnathion). www.indiandentalacademy.com
  49. 49. OBJECTIVE II www.indiandentalacademy.com
  50. 50. STEP III. OBJECTIVE: To express growth in a vertical direction in the mandible, and to draw the anterior portion of the mandible, soft tissue chin and the mandibular plane of Downs. a) Superimpose the V.T.0 Facial axis along the original facial axis. Move the V.T.0 tracing upwards so that the V.T.0 BaN line is above the original BaN line, the distance between these lines should be three times the amount of growth expressed previously in the frontonasal area. www.indiandentalacademy.com
  51. 51. b) Holding this position, copy the anterior portion of the mandible to include the symphysis, anterior 1/3 of lower border of the mandible and Downs’ mandibular plane c) Draw soft tissue chin from its anterior most point, extending this line posteriorly. Eliminate any evident hyper tonicity (mentalis action) by rounding out this area. www.indiandentalacademy.com
  52. 52. OBJECTIVE III www.indiandentalacademy.com
  53. 53. STEP IV OBJECTIVE: To express growth in a horizontal direction in the mandible (or lower face) and draw the posterior border of the mandible a) Superimpose on mandibular plane and move the V.T.O. forward until the original and V.T.O. foramina rotundae are vertically aligned. b) With the tracing in this position the posterior border and ramus of the mandible is drawn www.indiandentalacademy.com
  54. 54. OBJECTIVE IV www.indiandentalacademy.com
  55. 55.  STEP V.  OBJECTIVE: To locate and draw the maxilla, and lower half of nose. a) Superimpose the V.T.0 NA line on the original NA line and move the V.T.0 up until the vertical growth expressed above the BaN line and below the mandibular plane is in the ratio of 40:60. In other words, there is 40% of total vertical growth above the BaN line and 60% below the mandibular plane. b) With the V.T.0 tracing in this position copy the maxilla to include posterior 2/3 of hard palate, PNS to ANS to 2mm below the ANS. www.indiandentalacademy.com
  56. 56. c) With the V.T.0 In the same position, draw the new nose up to the middle of the inferior surface of the nose. Estimated growth usually parallels the contour of the old nose in this area. Average nose growth is 1mm per year www.indiandentalacademy.com
  57. 57. OBJECTIVE V www.indiandentalacademy.com
  58. 58. STEP VI. OBJECTIVE: To locate and draw the occlusal plane. a) With the V.T.0 super imposed on line NA move the V.T.0 tracing so that the vertical growth between the maxilla and the mandible is expressed as being 50% above the maxilla and 50% below the mandible. b) With the tracing in this position copy the occlusal plane. www.indiandentalacademy.com
  59. 59. OBJECTIVE VI www.indiandentalacademy.com
  60. 60. STEP VII OBJECTIVE: To determine the soft tissue lip contour using the “new” Holdaway line (HLine). The “Lip Contour Template” may be usefully employed as an aid in the location of the H-line. Dr Holdaway’s studies have shown that in “ideal” profiles, the distance between the depth of the upper lip contour and the H-line is between 3 and 7 millimeters. www.indiandentalacademy.com
  61. 61. Clinically judge the length of the upper lip. For short lips, use a 3 mm sulcus depth and a 7 mm sulcus depth for long lips. In lips of AVERAGE length a sulcus depth of 5mm is used. Having judged the lip length, use the “Lip Contour Template” to locate the H-line www.indiandentalacademy.com
  62. 62. OBJECTIVE VII www.indiandentalacademy.com
  63. 63. Lip contour template www.indiandentalacademy.com
  64. 64. USE OF TEMPLATE a) Judge the upper lip length to determine the most suitable lip contour profile for the patient. b) With the lower end of the H-line tangent to the chin soft tissue contour, slide the template up or down until the lip embrasure is located 3mm above the occlusal plane. c) Maintaining the lower end of the H-line tangent to the chin contour, move the upper end of the template forward or backward until a desirable, balanced and aesthetically “ideal” soft tissue profile contour is obtained. www.indiandentalacademy.com
  65. 65. d) Pencil a point in the centers of the circles at the top and bottom ends of selected template H-line. e) Joining the penciled points will provide the location of the H-line. f) Having determined the location of the H-line, the position of the lip embrasure and the upper lip sulcus depth, artistically draw the upper and lower lip contours. The upper lip should just touch the H-line, whereas the lower lip should lie approximately ½mm anterior to this line. www.indiandentalacademy.com
  66. 66. STEP VIII OBJECTIVE: To relocate maxillary central incisor PRINCIPLES: 1) Lip strain— Dr Holdaway contends that in well-balanced soft tissue profiles the distance along a horizontal line extending between a point 3mm below the original point A to the point where the line crosses the upper lip is within 1mm of the distance between the labial surface of the maxillary incisor to the tip of the upper lip. Should the lower measurement be less than within 1mm of the upper measurement, then lip strain is said to exist. To eliminate lip strain where it exists, the upper incisor is moved back to allow the aforementioned readings to be within 1mm of each other www.indiandentalacademy.com
  67. 67. 2) Where no lip strain exists retraction of the maxillary incisors allows the upper lip to move backwards an equal amount, i.e. lip and incisors maintain a 1:1 ratio. 3) Maxillary Incisor Rebound— generally, during post treatment maxillary incisors tend to move labially 0.5mm in Class I cases and 1.5mm in Class 11 cases. This is referred to as “Incisor Rebound”. Superimpose theV.T.0. Tracing on the NA line and the maxilla and trace in the maxillary incisor, taking cognizance of the amount it is to be repositioned. The axial inclination of this tooth is judged and the occlusal plane is used to locate it vertically. The tip of the maxillary incisor touches the occlusal plane. www.indiandentalacademy.com
  68. 68. OBJECTIVE VIII www.indiandentalacademy.com
  69. 69. STEP IX. OBJECTIVE: To reposition lower incisor and calculate resultant arch length change. 1) Having located the position of the upper incisor, judge the position and axial inclination of the lower incisor 2) To calculate lower arch length change, superimpose tracing on mandibular plane and register on symphysis. Measure the distance between old and new incisor position and double this measurement to determine total arch length discrepancy. www.indiandentalacademy.com
  70. 70. OBJECTIVE IX www.indiandentalacademy.com
  71. 71. STEP X. OBJECTIVE: To reposition lower first molar, use the plaster casts to determine arch length discrepancy due to crowding and/or rotation. Superimpose tracing on mandibular plane and register on symphysis. Incisor repositioning was 2mm lingually, thus effectively decreasing lower arch length 4mm www.indiandentalacademy.com
  72. 72. OBJECTIVE X www.indiandentalacademy.com
  73. 73. STEP XI. OBJECTIVE: To reposition maxillary first molar using the occlusal plane and lower first molar as a guide, draw the maxillary first molar in good Class I occlusion with the lower first molar www.indiandentalacademy.com
  74. 74. OBJECTIVE XI www.indiandentalacademy.com
  75. 75. STEP XII. OBJECTIVE: To complete artwork 1) ANS to upper incisor 2) Anterior portion of hard palate. 3) Lower alveolus lingually and labially. www.indiandentalacademy.com
  76. 76. OBJECTIVE XII www.indiandentalacademy.com
  77. 77. The mini visualized treatment objective was described by “MAGNESS” in 1987; it is a simple yet relatively accurate method of predicting the incisor and molar relations on the basis of growth and treatment alteration of the dentoskeletal framework. Obtainable treatment objectives are recorded on the original acetate tracings. In addition to space calculation, direction and magnitude of tooth movement are clearly indicated. It is an excellent visual aid during case presentation and may also be used to check on possible “midcourse” corrections during treatment and the evaluation of the final result compared with the original prediction. www.indiandentalacademy.com
  78. 78. *Weakness of manual prediction :1) Variability in lip thickness. 2) Degree of lip version 3) Lip tonicity 4) Methods are more cumbersome & time consuming. www.indiandentalacademy.com
  79. 79. *To overcome the limitations of manual prediction – computers moved into orthodontic practice environment. Ricketts advocated the use of computers to predict growth because of the time required to compare, organize & sort the data & then retrieve the information in a clinically useful form. He also stressed the need for individualizing the measurements according to age, sex, ethnic type & degree of maturation of each patient. www.indiandentalacademy.com
  80. 80. SURGICAL V.T.O www.indiandentalacademy.com
  81. 81. There are basically 2 types of surgical vto’s. They are 1) Orthodontic – Surgical VTO 2) Surgical VTO The orthodontic- surgical VTO is used for overall treatment planning & illustrates the effect of both orthodontic tooth movement & surgical skeletal changes. The surgical prediction is performed immediately before surgery to plan the specific surgical movements. They include no dental changes other those to be produced by surgery. www.indiandentalacademy.com
  82. 82. Reasons for performing Ortho-surgical VTO 1) To assess accurately the profile esthetic results of proposed surgery & orthodontics. 2) To determine the desirability of adjunctive surgical procedures like genioplasty. 3) To help determine the sequencing of surgery & orthodontics. 4) To help determine if extractions are necessary & to determine which teeth to extract if extraction is necessary. 5) To determine the anchorage requirements. www.indiandentalacademy.com
  83. 83. For the surgical – orthodontic patients, the treatment plan is constituted based on predictions made on the radiograph & the cast. The types of predictions are a) Cephalometric prediction : - allows direct evaluation of both dental & skeletal movements. b) Cast predictors:- show in detail the dental relationships that indirectly reflect the www.indiandentalacademy.com
  84. 84. Cephalometric prediction Manual Overlay tracing method Computer Software Template programmes method only Software programme & video imaging www.indiandentalacademy.com
  85. 85. Manual methods Tracing overlay:It’s the simplest way to simulate the effects of mandibular surgery. The final prediction tracing is produced without any intermediate tracings. This procedure is limited to surgery that does not affect the vertical position of the maxilla. www.indiandentalacademy.com
  86. 86. Steps in Overlay Tracing 1) The film is traced, all the teeth( especially the occlusal surfaces) are to be traced. 2) A new sheet is to be placed over the existing traced one & structures that will not be changed by the mandibular surgery are traced. www.indiandentalacademy.com
  87. 87. The structures not changed are, a) Cranial base, b) Maxilla & mandibular teeth c) Mandibular ramus down to the angle d) Soft tissue profile down to the base of the nose. *** mandible or soft tissue below the nose is not traced. www.indiandentalacademy.com
  88. 88. 3) The overlay tracing to be slid so that mandibular teeth can be seen through it in their desired post surgical position & trace the lower teeth & jaw. 4) The overlay tracing is superimposed on the cranial base to measure how far the lower has moved froward. Lower lip will go forward 2/3rd as far, mark is made at that distance. 5) Superimpose again on the mandible, soft tissue chin to be drawn & lower lip outline to be completed through the marked point. 6) Superimpose again on the cranial base & the soft tissue profile to be completed. www.indiandentalacademy.com
  89. 89. www.indiandentalacademy.com
  90. 90. Advantages of Overlay tracing 1) Dental casts are made available when cephalometric predicitons are carried out. 2) If major orthodontic tooth movement is anticipated before surgery, so that the orientation of the incisor teeth will change, it helps to have this simulated on dental casts in the form of orthodontic diagnostic setup. www.indiandentalacademy.com
  91. 91. Template method The use of templates for intermediate tracings between the original & final prediction tracing is mandatory, a) b) c) d) When the major movements of the teeth must be simulated. When the maxilla will be repositioned vertically When the chin is repositioned Only when the mandible is being moved. www.indiandentalacademy.com
  92. 92. Advantages:They can be used for any type of prediction. Disadvantage:More time consuming to prepare a template. Typical templates are made for the entire maxilla if a 1 or 2 piece maxillary osteotomy is planned. In cases wherein 3 piece maxillary osteotomy is planned, an anterior & posterior template have to be made. The posterior template would have to show , Posterior nasal spine till the second premolar While the anterior segment includes ANS, bony contour through point A & lingual contour of the alveolar process behind the incisors. www.indiandentalacademy.com
  93. 93. In the mandibular arch, the template includes the mandibular teeth & the entire outline of the mandible. The templates should be in different color from the original tracing so that it would be easy to interpret. www.indiandentalacademy.com
  94. 94. Surgical procedure for mandibular enhancement 1) The desired facial depth is indicated on the tracing. www.indiandentalacademy.com
  95. 95. Step 2:The prediction is began by tracing the distal portion of the mandible, soft tissue chin, & the occlusal plane on a clean piece of acetate. www.indiandentalacademy.com
  96. 96. Step 3:Slide the prediction forward along the chosen occlusal plane until bony pogonion lies on the line indicating the desired facial depth. www.indiandentalacademy.com
  97. 97. Step 4:Trace the fixed structures. www.indiandentalacademy.com
  98. 98. Step 5:Draw the A-Pogonion line & the facial axis on the prediction. These line are used to place the teeth in their ideal positions. www.indiandentalacademy.com
  99. 99. Step 6:Place the lower incisor in its ideal position ( wherein the incisal edge is 1mm ahead of the A-PO line & long axis at 22 degrees to the A-PO line. www.indiandentalacademy.com
  100. 100. Step 7:Superimpose the distal mandible of the prediction on that of the tracing. The change in position of the lower incisor is to be noted at this time. The amount of space required for axial inclination correction of the lower incisor is to be noted at this time, and the total arch length discrepancy is measured. www.indiandentalacademy.com
  101. 101. Step 8:The total arch length discrepancy amount is subtracted from the width of the tooth to be extracted, the remainder of the space is to be closed by bringing the molars forward. Molar is placed on the occlusion plane & advanced half the amount o f the extraspace. www.indiandentalacademy.com
  102. 102. Step 9:- place the upper molar in ideal class 1 occlusion. The upper incisor is placed in an ideal overbite & overjet Relationship with the long axis 5 degrees more upright than the new facial axis. The soft tissue profile is completed. www.indiandentalacademy.com
  103. 103. Step 10:Superimpose the prediction on the fixed structures of the tracing & note the changes. Antero-posteriorly upperlip vermillion will change in same direction as upper incisor movement, but only 2 half distance. Subnasale is not affected by dentall changes, so new lip is drawn in appropriate position & connected to subnasale by smooth curve. www.indiandentalacademy.com
  104. 104. Step 11:To indicate appropriate lip thickness, draw a dashed line on the tracing. www.indiandentalacademy.com
  105. 105. Step 12:- prediction to be laid on the tracing so that the lower lip on the tracing touches a) Upper lip b) Incisal edge of upper incisor c) Labial surface of the lower incisor. The vermilion border of the lip to be traced. www.indiandentalacademy.com
  106. 106. Step 13:Connect the lip to the soft tissue chin with a smooth curve to complete the tracing. www.indiandentalacademy.com
  107. 107. COMPUTER PREDICTION www.indiandentalacademy.com
  108. 108. Computer Imaging : The use of computer imaging simulated the probable treatment outcomes such as results of dental compensation or surgical orthodontic correction, which could facilitate communication about these alternatives by eliminating misconceptions. Full disclosure of the consideration of all valuable treatment alternatives had a great benefit from a risk management standpoint in addition to their bioethical merits. www.indiandentalacademy.com
  109. 109. Video imaging is another recent advancement in the field of orthodontic diagnosis. According to Turpin (1995) - orthodontist is generally influenced more by the objective findings whereas patient is guided by subjective issues. Orthodontic treatment planning is becoming an interactive process in which the patient and the parent are acting as co- decision makers. New and more effective tools are needed to help make such an important decision. One such tool is computerized video imaging. He concluded that computer imaging is the prediction and reporting of dental and facial changes. Describing the potential changes to the lay person has always been difficult. Practitioners frequently resort to the use of another patient’ records as an example. In reality the other patient may have little in common with the person whose treatment is being planned. Computer imaging provides a new tool for describing soft tissue changes. www.indiandentalacademy.com
  110. 110. According to Sarver (1996) computerized video imaging fits in this time proven treatment planning scenario. Video imaging technology allows the orthodontist to gather frontal and profile images and modify them to project overall esthetic treatment goals. In the course of surgical treatment, patients are very motivated to know what they will look after surgery. Profile line rendering may represent a reasonable feedback system for the orthodontist but has little cognitive value to the patients. It is possible to cut photographs and move the sections in a way that some what simulates the surgical outcome but does not allow the planner to visualizes limiting factors such as the dental relationship or differential soft tissue reaction to hard tissue movements. Gaps in manipulated photographs are unavoidable. www.indiandentalacademy.com
  111. 111. The use of video imaging technology allows us to modify facial images to project treatment goals and then discuss them with the patient. Video imaging is mush easier for a patient to comprehend than just the soft tissue profile of cephalometric tracings. Video imaging has the potential to touch almost every aspect of orthodontic practice, diagnosis and treatment planning, communication at consultation, database management, integration with practice management programmes, and many other areas that have not been fully realized yet. www.indiandentalacademy.com
  112. 112. COMPUTER PREDICTION The first step in using a computer program for cephalometric prediction is to enter a digital model of the patient’s tracing into computer memory. Even though the details of the digital model vary among the several currently available software programs the number of coordinate points (x,y) to represent the tracing are only limited. The more, the number of points to be digitized, the more time it takes to enter the tracing into the computer. Once an adequate digital model has been created, most computer programs operate quite analogously to the template method and key or mouse is used for moving the electronic template to a new position. Different surgical procedures can be depicted by moving the templates. www.indiandentalacademy.com
  113. 113. The computer method has two major advantages (1) the software programs have automatic adjustments in the soft tissue profile, or which speeds up the prediction process and makes it more consistent and another advantage (2) is with the digital model in computer memory, it is easy to produce several slightly different cephalometric predictions. Therefore the more predictions that are made the more advantageous it is to have the cephalometric data in an appropriate digital model (3) it also helps to integrate information from the dental casts with the cephalometric information. www.indiandentalacademy.com
  114. 114. RELIABLITY OF COMPTER PREDICTION Much attention has been devoted to facial esthetics, harmony, and balance as they relate to orthodontics. In essence, well proportioned and balanced soft tissue facial contours presuppose well defined underlying skeletal and dental structures. Many claim that correct positioning of the incisors allows the overlying soft tissues to be in balance and in harmony. The positioning of the mandibular incisors in particular has been cited as being the key to orthodontic diagnosis and treatment planning, because of its effects on esthetics. This is only a hypothesis. www.indiandentalacademy.com
  115. 115. The determination of facial balance for the particular individual being treated as judged from a two dimensional lateral head film tracing is subjective and at best only an estimate. So a video imaging or VTO of what a patient may look like after orthodontic treatment should have a written disclaimer placed on the print out, lest the patient perceive that the VTO is a guaranteed result. www.indiandentalacademy.com
  116. 116. CONCLUSION The V.T.O forecast is a valuable tool for the orthodontist (with regards to his self improvement), which permits him to set his / her goals well in advance for better comparison with the results which they obtain at the end of the treatment programme. www.indiandentalacademy.com
  117. 117. Thank you www.indiandentalacademy.com Leader in continuing dental education www.indiandentalacademy.com

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