Head gear in orthodontics

Head gear in orthodontics

1. WEL COME

2. HEAD GEAR Presented by: Md. Ishtiaq Hasan FCPS-II Trainee, Dept. of Orthodontics, DDCH Supervisor: Prof. Dr. Md. Zakir Hossain BDS, PhD(Japan) Prof. & Head, Dept. of Orthodontics, DDCH.

3. WHAT IS HEAD GEAR The orthodontic or orthopaedic appliance which deliver force intraorally or to the chin from a cranial extra-oral support.

4. COMPONENTS Facebow or a pair of ‘J’ hooks Force element Head cap

5. ‘J’ HOOK The extra-oral force is transmitted from the head cap to the hooks soldered on the arch wire by two seperate wire on each side.

6. FACE BOW Metallic component that transmit extra-oral force to the posterior teeth. It consists of ---Outer bow Inner bow & The junction

7. OUTER BOW Made of 1.5 mm stiff round wire contoured to fit around thc face.

8. INNER BOW Made of 1.25 mm round wire Contoured around the dental arch and molar Inserted into the buccal tube of upper first molar. Stops are placed mesial to the molar tube.

9. There are many ways in which the inner bow can be stopped at the mesial aspect of the buccal tube sothat the force is transmitted to the molars. Bayonet offset , ‘U’ loop or soldered stop can be used. ‘U’ loop have the advantage that it will allow for the adjustment to the antero-posterior length of the inner arch during treatment. This is necessary when the upper molars are being moved distally , in order to clear the bow from incisors.

10. THE JUNCTION It is a rigid joint of inner and outer bow. It can be a single soldered joint.

11. THE FORCE ELEMENT It is the part of the head gear which provides the force to bring about the desired effect. May conprise of spring , elastics or other streatchable materials. It connect the face bow to head cap.

12. THE HEAD CAP The appliance takes anchorage from the rigid bones of the skull or from the back of the neck. The point of anchorage ---Cervical Occipital Parietal

13. HOW TO CONSTRUCT HEAD GEAR

14. PRINCIPLES OF USE OF HEAD GEAR Head gear have the ability to move the dentition and the maxilla in all 3 planes of space. The following factors should be considered when planning the use of head gear---

15. CENTRE OF RESISTANCE OF THE DENTITION The COR for a molar is usually at the mid root region ,1-2mm apical to the furcation area.

16. If forece is passing through the COR , it causes bodily movement. If force is above COR , it causes distal root tipping. If force is below COR , it causes distal crown tipping.

17. DIRECTION OF FORCE Cervical head gear produce a inferior and distal force on the teeth ,while high pull head gear produce a superior and distal force on the teeth and maxilla.

18. CENTRE OF RESISTANCE OF MAXILLA The COR of the maxilla should also be considered when planning for head gear. COR of maxilla is located above the apices of the premolar teeth. Forces passing through the COR of maxilla produce translation of the maxilla in a distal direction while forces above or below this point causes rotation of maxilla.

19. POINT OF ATTACHMENT OF FORCE Point of attachment of force means the point where the hooks of the outer bow is connected to the elastics. It is possible to alter the direction of force by altering the point of attachment. This can be done by varying the length of the outer bow or by varing the angle between the inner and outer bow.

20. MAGNITUDE OF FORCE To measure the force level , strain gauge should be used. Some commercial head gear , force level indicator built into the traction spring. Excessive force level will result in the appliance being difficult to place and pt will very quickly complain of discomfort.

21. TYPES OF HEAD GEAR Cervical head gear Occipital head gear High pull head gear Combination head gear

22. CERVICAL HEAD GEAR Obtain ancorage from the nape of the neck. Causes distal and extrusive movement of the upper molars leadind to increase in lower facial height.

23. INDICATION Generally indicated in class-II deep bite cases sothat lower facial height can be increased.

24. CONTRA-INDICATION Pt with long face syndrome Open bite cases Gummy smile

25. ADVERSE EFFECT undesirable

26. To minimize the extrusive force , we can bend the outer arm upward. Bringing the outer bow down to the line of action of neck strap create an upward pressure which counteract the downword pressure of elastics.

27. OCCIPITAL HEAD GEAR Derive anchorage from the occipital region (back of the head). Produce distal and some intrusive frce.

28. HIGH PULL HEAD GEAR Derive anchorage from parietal region(Front of head). Cause intrusion of upper molar and maxilla, leading to decreased lower facial height.

29. INDICATION In class-II long face patient. Open bite cases

30. CONTRAINDICATION Deep bite cases.

31. ADVERSE EFFCET Intrusion of the molars undesirable

32. COMBINATION HEAD GEAR Here cervical and occipital anchorage are combined. It allow a distal force straight through the centre of resistance by having equal occipital and cervical components.

33. USES OF HEAD GEAR

34. ORTHOPAEDIC EFFECT Forces applied onto the maxilla can be used to restrict its downward and forward growth. For this , distal force should be applied through the COR of the maxilla. 350-450 gm force on each side for a minimum of 12-14 hrs/day are required for this.

35. ANCHORAGE REINFORCEMENT When intra-oral anchorage is insufficient , then head gear can be used. 300 gm/side force level for 10 hrs/day is needed for this.

36. DISTALIZING THE MOLAR Distal movement of molar may be required for correction of molar relation or to gain space for correction of crowding or retraction of anteriors. 300 gm/side for 14 hrs/day is needed for this. The use of head gear for 14 hrs each night with a force passing through the COR of upper first molar will move the tooth distally 2-4 mm/2-4month without tipping.

37. DISTALIZING THE MOLAR As the molar move distally, the bow will impinge against the incisors, so it is necessary to lengthen the inner arch. The ‘U’ loop need to expand to increase the length of the inner arch. Occlusion should be checked and ensure that the distal movement is not hampered by the interference of the lower molar. If it happens , a removable appliance with anterior bite plane can be used.

38. CORRECTION OF MOLAR ROTATION AND EXPANSION Correction is achieved by adjustment of the inner bow sothat it will produce rotational force to the molar or expansion of the arch.

39. SPACE MAINTAINER Most effective method of maintaining arch length is by the use of head gear. The mesial movement of molar is protected and the face bow does not interfere with the erupting teeth. For this , 8 hrs/day wear is sufficient.

40. EXTRA-ORAL ANCHORAGE FOR THE MANDIBULAR ARCH This is usually achieved by ‘j’ hooks because placement of inner bow in the lower buccal tube is difficult. If extra-oral anchorage is already in use in the upper arch, anchorage reinforcement can be achieved by cl-III intermaxillary traction at the same time. Sliding jig can also be used to transmit the force to the lower jaw.

41. PRACTICAL MANAGEMENT At first , select the appropiate size of face bow. Then determine the COR of tooth mentally. Mark the COR on the pt’s cheek. Choose the type of head gear. Allow the outer bow to rest away from chek and adjust its length and position with respect to COR to achieve proper line of force. Monitor for changes as treatment proceed and adjust the force line of action if necessary.

42. Since extra-oral traction depends on pt’s co-operation , it is vitally important at each visit to assess wheather the appliance has been worn sufficiently or not. A ‘time sheet’ should give to the pt where he will keep record about the time of wearing of head gear. Pt should be asked to fit the head gear and observed to ensure that he is familiar with the insertion. Any difficulty in fitting may be a sign of poor co-operation. The head cap should give the appearance of having been worn. The elastic should lost some of its elasticity.

43. THE MOST IMPORTANT ELEMENT COMPLIANCE!

44. CASE PRESENTATION

45. PARTICULARS OF THE PATIENT WITH PRESENTING COMPLAINS: Simu, age 9 years, student,came to DDCH with the complains of proclination of upper ant. teeth and aesthetic problem.

46. LOCAL EXAMINATION EXTRA-ORAL Right profile view Frontal view Left profile view

47. Her face appeared to be symmetrical with convex profile. Shape of the head : Mesocephalic. Facial profile : Convex Facial divergence : posterior. Vertical relation : normal Shape of the face : Oval. Facial symmetry : Symmetrical. Lips : Potentially competent. Upper lip line : Normal. Lower lip line : Low Naso-labial angle : Normal Mento-labial depression : Deep Breathing : Nasal .

48. LOCAL EXAMINATION INTRA-ORAL Frontal view Right buccal view Left buccal view

49. OCCLUSAL VIEW UPPER LOWER

50. INCISOR RELATIONSHIP

51. MOLAR AND CANINE RELATIONSHIP

52. OCCLUSAL RELATIONSHIP: Anterior posterior relation: 1. Molar relation : Class-II both sides. 2. Canine relation : Class-II on both sides. 3. Incisor relation : Class-II div I 4.Overjet : 10mm B. Vertical relationship: 1. overbite : 5 mm. C. Lateral relation: 1. Midline : Coinside 2. Cross bite : Absent

53. 1. Model Analysis / Space analysis : Upper arch Lower arch Arch perimeter_ Total tooth material = 97mm – 102mm = -- 5 mm Arch perimeter —Total tooth material =85mm — 92mm = --5 mm Remarks: Crowding in both the arches due to teeth jaw discrepancy.

54. OPG

55. CEPHALOMETRIC X-RAY

56. AETIOLOGY DENTOALVEOLAR DISPROPORTION THUMB SUCKING FAMILY HISTORY(MOTHER)

57. DIAGNOSIS : It is a case of class II div I malocclusion with crowding & proclination of upper anterior segment; crowding of lower ant segment. Canine & molar relationship is class II on both side .

58. Treatment plan: 1 . URA with ant. bite plane to open the bite. 2.URA with palatal finger spring(1 mm SS wire) on to fascilate distal movement of the upper molars with bands and extra-oral traction. 3. Reasses the case for further treatment. 6 6

59. Thanks to all