Mbt technique part

MBT, pea ,fixed applaince, mclaughlin, bennett and triversi

1. Umar Mohamed PART I

2. CONTENTS . Introduction Brief history An overview of treatment mechanics Appliance specification – Variations and Versatility Bracket positioning Arch form Anchorage control during levelling and aligning Arch wire sequence Over bite control Space closure by Sliding mechanics Finishing the case Appliance removal and retention protocol References

3. Introduction

4. FUNDAMENTALS OF TREATMENT MECHANICS

5. The Work of ANDREWS

6. The work of Roth

7. The work of McLaughlin and Bennett between 1975 and 1993 Worked with SWA brackets . Redefined treatment mechanics based on sliding mechanics continues light forces

8. The work of McLaughlin Bennett and Trevisi between 1993 and 1997 Redesigned entire bracket system MBT TM is a version of Preadjusted bracket system specifically for use with Light continuous forces , Lacebacks , bendbacks and designed to work with sliding mechanics

9. Anterior tip specification for original SWA greater than research findings

10. The work of McLaughlin Bennett and Trevisi between 1997 and 2003

11. Overview of the MBT treatment philosophy Bracket selection Versatility of the bracket system Accuracy of bracket positioning Light continues forces The .022 vs the .018 slot Anchorage control in early treatment Group movement The use of three arch forms One size rectangular steel wires

12. Arch wire hooks Method of archwire ligation Awareness of tooth size discrepancies Persistence in finishing

13. Bracket selection Accuracy of bracket positioning

14. Light continues forces Most effective way to move teeth is being comfortable to patient and minimizing the threat to anchorage Thin, flexible wires early on ,with minimal deflection and avoid too frequent arch wire changes. Clinician needs to recognize the signs of excess forces Later in sliding mechanics ,light continues forces are applied using active tie backs and rigid .019x.025 steel working wires

15. The .022 versus the .018 slot

16. Anchorage control in early treatment

17. Group movements

18. One size of rectangular steel wire

19. Arch wire hooks

20. Appliance Specification -Variations and Versatility

21. Design features of a modern bracket system Range of Brackets

22. i.d system and shape of the bracket

23. Torque in base –computer aided design(CAD) factor

24. TIP SPECIFICATION

25. TORQUE SPECIFICATION

26. Recommended torque

27. Incisor torque It is helpful clinically have torque control which moves upper incisor roots palatally and lower incisor roots labially . This treatment is necessary for many types of malocclusison

28. Class II cases, Torque lose on the upper incisors and where lower incisors tends procline during levelling and in response to class ii elastics. Class I cases, correct torque help to achieve anterior tooth fit Class iii cases Correct torque can help to compensate for mild class iii dental bases

29. Canine torque

30. Upper premolar and molar toque

31. Lower Premolar and molar torque Many orthodontic cases showed narrow maxillary arch with lower arch showing compensating narrowing . They require buccal crown torque ( uprighting ) Rolling-in

32. The Versatility of the MBT Bracket System

33. Versatility

34. 1.Palatally Displaced Upper Lateral Incisors

35. Three torque for upper canine (-7 ,0 ,+7 ) & lower canine (- 6 ,0 ,+6 )

36. Effective torque control of the upper canines is necessary, because they are key elements in a mutually protected occlusion. The inefficiency of the PEA in delivering torque is evident when working with canines (longest roots in the human dentition). The MBT philosophy used two type of canine brackets (in each arch) to provide three possible torque options (in each arch).

37. 1. Arch form Well developed arches: (not requiring substantial tooth movement) -7 ° upper canines -6 ° lower canines Ovoid or tapered arch form: ° for upper canines ° for lower canines Narrow tapered arch form: +7 ° upper canines +6 ° lower canines

38. 2. Canine prominence Prominent canines or Gingival recession present: upper canines = 0 ° or +7 ° torque lower canines = +6 ° torque

39. 47 3. Extraction decision In premolar extraction cases or In cases where there is considerable canine tip to be corrected: ° torque As they tend to maintain the canine roots in cancellous bone, thereby making tip control of the canine roots easier . Canine bracket carries a hook

40. 4. Overbite In class II/2 cases and Other deep bite situations Lower canine = 0 ° or +6 ° torque There is often a requirement to move the lower canine crowns labially , but to maintain the roots centered in the bone.

41. 49 5. Rapid palatal expansion cases Widening of the upper arch creates a secondary widening in the lower arch = torque changes among lower teeth. lower canine = 0 ° or +6 ° torque Recommended to assist this favorable change.

42. 6. Agenesis of upper lateral incisor If to close the spaces of missing lateral incisors with canine mesialization : Canine bracket = +7 ° torque

43. 51 Interchangeable lower incisor brackets Interchangeable

44. Interchangeable upper premolar brackets

45. 53 Use of upper second molar tubes on first molars in non HG- cases

46. 54 Finishing to a Class II molar relationship  Use of second molar tubes for the upper first and second molars of the opposite side . .

47. Bracket positioning and case setup

48. BRACKET POSITIONING

49. Direct visualization HORIZONTAL POSITIONING VERTICAL POSITIONING AXIAL POSITIONING

50. Rotations On a rotated tooth the bracket bonded slightly more mesially or distally, with a very small amount of excess composite under the mesial or distal of the bracket base.

51. Clinical Use of gauges

52. Upper first molar band placement When viewed from buccal side ,the tube and band should be parellel to buccal cusps It is common error to allow the band to seat too gingivally at the distal,causing excessive crown tip. Mesio -distally the bracket should straddle the buccal groove

53. Lower first molar band placement Correct band positioning . A common error is to allow the band to seat too gingivally at the mesial .

54. Horizontal bracket placement errors If brackets are placed to the mesial or distal of the vertical long axis of the clinical crown, improper tooth rotation can occur.

55. Axial or paralleling bracket placement errors These will occur if the bracket wings do not straddle the vertical long axis of the crown in a parallel manner. Such errors lead to improper crown tip.

56. Thickness errors. Excess bonding agent beneath the bracket base can cause thickness and rotational errors. Can be eliminated by pressing the bracket against the tooth.

57. Vertical errors Vertical errors in bracket placement are caused by placing brackets gingival or incisal\occlusal to the center of the clinical crown. May lead to extrusion or intrusion.

58. Gingival Concern. Partially erupted tooth. It is difficult to visualize the center of the clinical crown on partially erupted teeth, when treating young patients.

59. Gingival Inflammation Top:Healthy gingivae. Bottom :The same case with inflamed gingivae in the upper right quadrant . Gingival inflammation causes foreshortening,effectively reducing the length of the clinical crowns.

60. Teeth with palatally or lingually displaced roots. Individual teeth with lingually displaced roots can produce short clinical crowns.

61. Incisal or Occlusal concerns. Incisal crown fractures or tooth wear make it difficult to visualize the center of the clinical crown. Restore crown

62. 71 Technique for Vertical Bracket Placement Measuring the clinical crown heights on as many fully erupted teeth as possible

63. The bracket placement guide is used to supplement the visual technique and is most helpful in those cases where the center of the clinical crown is difficult to locate due to partial eruption, gingival inflammation, or abnormal tooth size and shape .

64. Chart individualization in premolar extraction cases 74 Chart individualization in deep bite and open bite cases Deep-bite cases - the incisor and canine brackets 0.5 mm more occlusally. Open bite cases - 0.5 mm more gingival