Arch forms /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.

Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078

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Arch forms /certified fixed orthodontic courses by Indian dental academy

  1. 1. ARCH FORMS INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  2. 2. OVERVIEW •INTRODUCTION •REVIEW OF LITERATURE •ANATOMY •FACTORS AFFECTING ARCH FORM •PREFORMED ARCHWIRES •DIAGNOSIS •STABILITY & RELAPSE www.indiandentalacademy.com
  3. 3. INTRODUCTION The achievement of a stable, functional & esthetic arch form has long been one of the prime objectives of orthodontist from the period of Edward Angle. www.indiandentalacademy.com
  4. 4. SEARCH FOR IDEAL ARCH FORM 1. Bonwill –1885  Tripod shape of lower jaw  Equilateral triangle Base – Condyle to Condyle Sides – Condyle to midline  Bicuspids & molars formed a straight line from cuspid to condyle 2. Hawley -1905 www.indiandentalacademy.com
  5. 5. Bonwill -Hawley Arch Formula  Anterior teeth should be made to lie along a circle whose radius equaled their combined widths  Equilateral triangle Base – Intercondylar width  Should be used only as a guide in establishing arch form www.indiandentalacademy.com
  6. 6. BONWILL – HAWLEY CHART www.indiandentalacademy.com
  7. 7. 3. Black -1902  Upper teeth are arranged in a semi-ellipse & lower teeth arranged on a smaller curve. www.indiandentalacademy.com were
  8. 8. 4. Broomel -1902 The teeth are arranged in the jaws in the form of two parabolic curves, the superior arch describing the segment of a larger circle than the inferior , as a result of which the upper teeth slightly overhang the lower. www.indiandentalacademy.com
  9. 9. 5. Angle –1907 – Line of occlusion Definition The line with which, in form & position according to type, the teeth must be in harmony if in normal occlusion. • This line resembles parabolic curve but varies due to Race Type Temperament of the individual www.indiandentalacademy.com
  10. 10. LINE OF OCCLUSION •Upper Molar – central fossa Anterior- cingulum •Lower Molar – buccal cusps Anterior –incisal edges www.indiandentalacademy.com
  11. 11. Angle -1907 Bonwill –Hawley Arch form- General approximation of the true line of occlusion Objected the straight line from cuspid to third molar Straight line existed from the cuspid to the MB cusp of the I molar,however, there was a natural curvature needed in the molar region. www.indiandentalacademy.com
  12. 12. 6. Grays Anatomy -1942 Maxillary dental archform- Elliptical curve Mandibular dental archform- Parabolic curve www.indiandentalacademy.com
  13. 13. 7. Chuck, 1934-AO –Ideal arch form Square Round Oval Tapering •BH archform – not suitable for every patient, can be used as a template •Bicuspid region should be wider than the cuspids to prevent excessive expansion of the cuspids. www.indiandentalacademy.com
  14. 14. 8. Boone AO-1963 Similar superimposition of the BH archform on a mm template. 9. Mac Conaill & Scher 1949 It is impossible for an ellipse & a parabola to meet one another at every point. www.indiandentalacademy.com
  15. 15. Mac Conaill 1949 Catenary curve – Ideal curve of common occlusion Catenary curve is formed by suspending a chain or flexible cable of appropriate length from two points of varying width www.indiandentalacademy.com
  16. 16. Scott 1957 Shape of the human arch - Catenary curve Broodie & Lillie 1966 Basic bony arch is established as early as 9.5 weeks in utero & the arch was of a catenary design www.indiandentalacademy.com
  17. 17. Disadvantage of Catenary curve Does not give a good fit in the II & III molar region www.indiandentalacademy.com
  18. 18. 10. Musich –1973, AJO Catenometer –Device for construction of arch perimeter 11. Brader –1972-AJO Dental arch form was made up of teeth which assume unique positions along a compound curve representing an equilibrium at all points and delimited by the counterbalancing forces of the tongue and circumoral tissues. www.indiandentalacademy.com
  19. 19. CATENOMETER www.indiandentalacademy.com
  20. 20. Brader arch form The geometry of the dental arch form was best represented by a Trifocal ellipse, with the teeth occupying the portion at the constricted end of the curve. www.indiandentalacademy.com
  21. 21. BRADER ARCHFORM www.indiandentalacademy.com
  22. 22. Brader arch form  Arch guide with 5 arch forms  Selection of proper form –Arch width at the II molars  Maxillary arch form is selected one size larger than the mandibular arch form Drawback – Excessive narrowing in the cuspid region & excessive wear of the incisal portion of the cuspids www.indiandentalacademy.com
  23. 23. 12. Rocky mountain Data systems – Computer derived Arch design • Inter molar width • Inter cuspid width • Arch depth • facial type www.indiandentalacademy.com
  24. 24. SURESMILE TECHNOLOGY Dr. Rohit sachdeva, JCO- 2000. DIGITAL ARCHWIRES www.indiandentalacademy.com
  25. 25. LINGUAL ORTHODONTICS Mushroom archwire www.indiandentalacademy.com
  26. 26. STANDARD ARCHFORM www.indiandentalacademy.com
  27. 27. Functional anatomy Although bone is the hardest tissue in the body, it is one of the most responsive to change when there is an alteration in the musculature. The dental arch form is initially shaped by the supporting bone & following eruption of teeth, by the musculature & intraoral functional forces. www.indiandentalacademy.com
  28. 28. Buccinator mechanism Tongue www.indiandentalacademy.com
  29. 29. Buccinator mechanism www.indiandentalacademy.com
  30. 30. Balance of muscle forces & Arch form •Between the tongue and perioral musculature, there is no balance of force • During swallowing tongue pressures are considerably greater than those exerted by the cheeks & lips www.indiandentalacademy.com
  31. 31. EQUILIBRIUM ??? www.indiandentalacademy.com
  32. 32.  Buccal forces operate constantly throughout the day.  Occlusal forces also help to maintain the equilibrium. Dental equilibrium – Dynamic equilibrium Posterior teeth may be moving buccally during swallowing, but the forces of the cheeks return them to a more lingual position, occlusal forces also produce buccolingual movements www.indiandentalacademy.com
  33. 33. Facial form Vs Arch form  Leptoprosopic – Narrow dental arches  Euriprosopic - Broad, round arches  Mesoprosopic – Average/ parabolic arches www.indiandentalacademy.com
  34. 34. FACTORS AFFECTING ARCH FORMS www.indiandentalacademy.com
  35. 35. Malocclusion Class II – Narrow & Tapered maxillary arch form - Ovoid mandibular arch form. Class III- Tapered mandibular arch form - Ovoid maxillary arch form. www.indiandentalacademy.com
  36. 36. Stanley Braun et al –AO, 1998 Class II Maxillary arch – Narrower Mandibular arch – z width & Depth Class III Maxillary arch – Arch width Mandibular arch - Arch width Arch depth www.indiandentalacademy.com
  37. 37. Habits Thumb sucking – Narrow dental arches Tongue thrusting – Narrowing of the maxillary arch www.indiandentalacademy.com
  38. 38. PREFORMED ARCHWIRES www.indiandentalacademy.com
  39. 39. Basic components • The anterior curvature • Inter cuspid width • Inter molar width • Curvature from cuspids to II molars www.indiandentalacademy.com
  40. 40. VARI SIMPLEX DISCIPLINE ARCH FORM •Not based on clinical examination •Result of research by Dr. Garland McElvain www.indiandentalacademy.com
  41. 41. Final arch form •Fitted to the original study model of the mandibular arch • cuspids should not be expanded. • Wax bite of the maxillary arch is examined • Mandibular II molars – toe in www.indiandentalacademy.com
  42. 42. Roth – Tru Arch form •Modified catenary curve •5 separate radii •Over correction concept www.indiandentalacademy.com
  43. 43. MBT ARCH FORMS Arch forms [Chuck-1934 ] – Tapered Square Ovoid MBT - 3 Archforms in early treatment Individual archform in final stages These archforms vary mainly in interPm, intercanine width of 6mm. www.indiandentalacademy.com
  44. 44. TAPERED ARCH FORM •Narrowest intercanine width •Indications narrow arches gingival recession single arch Rx www.indiandentalacademy.com
  45. 45. SQUARE ARCHFORM •Indications Broad arches Buccal uprighting & expansion of post To maintain expansion www.indiandentalacademy.com
  46. 46. OVOID ARCHFORM •Most preferred •Good stability & •Minimum relapse www.indiandentalacademy.com
  47. 47. CUSTOMIZING ARCHWIRES  Done according to the lower arch  Upper archform –3mm wider in all areas After the rectangular HANT wires in approximate form for the patient as determined using the clear template. www.indiandentalacademy.com
  48. 48. INDIVIDUALIZED ARCHFORM PROCEDURE Wax template is molded over the lower arch 19x25 ss arch wire is bent to the indentations Compared with starting lower model Checked for symmetry Xerox copy of the wire is made & stored www.indiandentalacademy.com
  49. 49. 3M UNITEK • Tapered archform –Orthoform I • Square archform –Orthoform II • Ovoid archform -Orthoform III www.indiandentalacademy.com
  50. 50. Nojima et al – AO, 1971 Caucasian sample Japanese sample www.indiandentalacademy.com
  51. 51. PRE FORMED ARCHWIRES The normal variation in arch form, are not reflected in the preformed arch wires presently available & it is important to keep in mind during orthodontic treatment that if preformed arch wires are used, their shape should be considered a starting point for the adjustments necessary for proper www.indiandentalacademy.com individualization.
  52. 52. DIAGNOSIS OF ARCHFORM 1. Clear templates - Early indication TAPERED OVOID SQUARE www.indiandentalacademy.com
  53. 53. 2. Hassan Noroozi et al, AO-2001 Defined arch forms using the following parameters •Inter II molar width •Inter canine width •II molar depth •Canine depth www.indiandentalacademy.com
  54. 54. Square archform Inter canine width/ Inter IImolar width Canine depth / Molar depth Tapered archform Canine depth / Molar depth Intercanine width / Intermolar width www.indiandentalacademy.com
  55. 55. STABILITY & RELAPSE www.indiandentalacademy.com
  56. 56. Riedel- 1969 Arch form, particularly in the mandibular arch, cannot be permanently altered during appliance therapy. www.indiandentalacademy.com
  57. 57. Strang , AO- 1949, AJO- 1946 Howes, AJO- 1960 Inter molar width was normally decreased during extraction Rx, however, that if cuspids were moved distally into extraction sites, they could be expanded buccally to limits offered by their new distal location. www.indiandentalacademy.com
  58. 58. Amott-1962, Arnold-1963,Welch-1956 Bishara AJO-1973 With regard to extraction cases, intermolar width decreased post Rx, but inter cuspid width which retained its original dimension did not show an increased arch width as was previously thought. www.indiandentalacademy.com
  59. 59. Shapiro AJO-1974 Mandibular intercuspid width demonstrated a strong tendency to return to its pre Rx dimension in all groups except cl II, div 2.  Mandibular arch length decreased substantially in every group during post- retention period. www.indiandentalacademy.com
  60. 60. Gardner , AJO-1976 Inter cuspid width was expanded during Rx but had a strong tendency to return to its original pre Rx width in both ext & nonext cases. Inter I pm width showed the greatest Rx increase in width with only a minimal post Rx reduction II pm width for nonext cases showed a significant increase with slight tendency www.indiandentalacademy.com for post- retn decrease.
  61. 61. II pm width for ext cases showed a decrease with Rx & a slight continued decrease post- retention Inter molar width Non ext cases –increase in width with Rx Extraction cases – decrease with Rx Post retention - no change www.indiandentalacademy.com
  62. 62. Felton et al, AJO- 1987 70% of the dental arches returned to their original shape during the post Rx period. www.indiandentalacademy.com
  63. 63. De La Cruz et al, AJO 1995  Arch form tended to return toward the pre Rx shape after retention & that the greater the Rx change, the greater the tendency for post- retention change.  Patients pre Rx arch form appeared to be the best guide for future arch form stability. www.indiandentalacademy.com
  64. 64. CONCLUSION The search for an ideal arch form, suitable for every patient, has been an unrealistic goal because of the wide individual variation. The basic principal of arch form in orthodontic Rx is that within reason, the patients original arch form should be preserved. Retention should certainly be an important consideration when original arch form is changed during www.indiandentalacademy.com Rx.
  65. 65. Thank you For more details please visit www.indiandentalacademy.com www.indiandentalacademy.com

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