In July 2000, the American Board of Orthodontics (ABO) came out with revised requirements and a grading system for dental casts and panoramic radiographs.4 It is the authors' hope that this book will be helpful to readers wanting to reach ABO goals.
T he ABO places emphasis on self assessment of seven features of dental casts. Interestingly, these seven criteria for cast evaluation quite closely match the finishing goals described in this chapter, and throughout the book. Progress models, taken in the finishing stages of treatment, and before appliance removal, should be checked for ABO requirements for any case which is intended for presentation. More specifically, these include:
• Tooth alignment. Almost 80% of malalignments were found to occur among lateral incisors and second molars. Care with bracket positioning (pp 61, 66, and 67) can help to eliminate such errors.
• Marginal ridges. Accuracy in vertical relationship of the marginal ridges is improved by using gauges and bracket positioning charts (pp 62-65), taking extra care in first and second molar regions, which are the most frequent problem areas.
• Buccolingual inclination. The torque features in the recommended bracket system (p. 33 and Fig. 4.40, p. 89) are specifically intended to deliver correct buccolingual inclination in the molar regions.
• Occlusal relationship. T he A/P relationship of molars, premolars and canines is assessed using Angle's classification. Coordination of tip, torque, and tooth size (with correction where necessary) is required (p. 282), to achieve Class I occlusion, and this is a theme running throughout the book.
• Occlusal contacts. Good posterior occlusion can normally be achieved with the help of vertical elastics (p. 294). Additionally, well-constructed positioners can help to settle cases intended for ABO presentation. A common problem area was reported to be upper and lower second molars.4
• Overjet. Methods of overjet correction are reviewed in Chapters 7 and 8. Attention also needs to be given to tip, torque, and tooth size (p. 282).
• Interproximal contacts. Techniques for closing spaces (p. 254), and for keeping them closed during finishing (p. 286), have been described. Particular care is needed in adult extraction cases (p. 268).
Finally, concerning root angulation asessment using panoral radiographs, it has been a consistent finding with the MBT™ system, that root angulations match the ABO requirements, especially concerning canine roots.
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