managementofopenbitedralaa-200817143512.pptx

Management of openbite

1. MANAGEMENT OF OPEN BITE Under supervision of Dr Maher Fouda Dr Alaa elkasaby Professor of orthodontics Mansoura Egypt

2. Definitions Open Bite( Negative Overbite): - Inherited ,developmental or acquired maloccluison (vertical occlusal anomaly) whereby no vertical overlap exists between maxillary and mandibular anterior teeth ( anterior open bite- AOB-)when posterior teeth are brought in to maximum intertcuspation ,or no vertical contact is exhibited between maxillary and mandibular posterior teeth ( posterior open bite-POB- ). - An open bite may be localized and thus involve only a few teeth due to a digit sucking habit or other local factors( dental open bite),or it may be caused by divergence of the skeletal planes ( skeletal open bite or apertognathia ).

3. Anterior open bite . Posterior open bite

4. Vertical overlap of Incisors Anterior open bite (AOB): there is no vertical overlap of the incisors when the buccal segment teeth are in occlusion Posterior open bite (POB): when the teeth are in occlusion there is a space between the posterior teeth Incomplete overbite: the lower incisors do not occlude with the upper incisors or the palatal mucosa . The overbite may be decreased or increased Increase Over bite(o/b ) Normal o/b Incomplete o/b AOB

5. Classifications of Open Bite According to Moyers 1988 it can be classified in to: 1-Simple( Dental,functional ) open bite : Anterior or Posterior 2- Complex ( Skeletal) open bite : which could be associated with Class I ,Class II or Class III skeletal discrepancies

6. Classifications of Open Bite A simple clinical diagnostic classification might be as follows: anterior open bite with increased facial proportions anterior open bite with history of digit sucking and normal facial proportions anterior open bite with no history of digit sucking and normal facial proportions EXCELLENCE IN ORTHODONTICS 2005

7. According to location: Anterior open bite Posterior open bite Unilateral bilateral According to anatomical site involved: Dental (simple) Skeletal (complex) Combined (skeletal, functional)

8. According to severity: Pseudo open bite (open bite less than 1 mm). Simple open bite ( anterior open bite more than 1 mm but posterior teeth in occlusion) Complex open bite ( extend from 2nd premolar on one side to the 2nd premolar on the other side) Compound open bite ( includes molars). Iatrogenic open bite (improper orthodontic therapy)

9. Anterior Open Bite (AOB)

10. Etiology : 1- Transitional 2- Skeletal 3- Habits 4- Soft tissues 5- Trauma 6- Iatrogenic 7- Mouth breathing & Head posture 8- Neurological disturbances. 9- Localized failure of development 10- Muscular dystrophy.

11. 1-Transitional : during eruption of teeth, patients are children in the transitional dental stage, it is conceivable that the rate of eruption of the anterior teeth will slow down temporarily. These subjects are often referred to as having "transitional or pseudo open-bite".

12. 2-Skeletal: Discrepancy in vertical development Anterior & Posterior  Backward Rotation (Bjork) Skeletal features: 1- Increased LAFH and there may be vertical maxillary excess ( supragnathism ), ‘long face syndrome’ or Ricketts’ dolichofacial type(1961) . 2- Steep mandibular plane & gonial angle. 3- Reduced posterior FH. 4- Divergent cephalometric planes ( sassouni analysis) In these cases AOB is usually symmetrical and in severe cases only terminal molars contact. Clinical Success in early orthodontic treatment 2005

13. The Frankfort Mandibular Planes Angle (FMPA) is usually increased. In contrast to open bites caused purely by habit, in which there is impedance of incisor eruption by the digit, in true skeletal open bite incisor eruption may be increased in relation to the underlying basal bone, although it still fails to compensate for the excessive vertical development of the jaws.

14. Bjork identified seven structuralsigns related to significantly abnormal mandibular growth rotations: inclination of the condylar head; curvature of the mandibular canal; shape of the lower border of the mandible; inclination of the symphysis ; interincisal angle; interpremolar or intermolar angle; lower anterior face height. Dental Update – June 2003

15. 3- Habits: ( Duration & Intensity) Thumb sucking Digit sucking Dummy sucking( sucking the pacifier ).

16. This open-bite is caused by obstruction of eruption of the anterior teeth. Classically, this open-bite is asymmetrical and fits snugly around the offending agent. Many of these cases show spontaneous remissions , and about 75 to 80% had marked improvement without any form of treatment.

17. 4- Soft tissues: A - Tongue posture & Function: All AOB exhibit anterior tongue thrust,but not all AOB are caused by anterior tongue thrust. Two Condition exists: i- adaptive tongue thrust( secondary) ii- endogenous tongue thrust (primary)  rare & difficult to distinguish

18. B-Lymphatic tissues: Large adenoid  Mouth breathing  Mandible postured downward  separation of posterior teeth  over eruption  increase in Lower Vertical Dimension  Open Bite The ‘Adenoid face’ consists of a narrow face, protruding teeth, and lips separated at rest, and has often been attributed to chronic mouth breathing.

19. 5- Trauma (pathological) : Bilateral fractured of the condyles. Ankylosis of Condyles Le Fort II and III fracture cases often present with gagging occlusion, hence anterior open-bite.

20. 6- Iatrogenic: - This open-bite is produced by active orthodontic treatment 1- the use of anterior bite plane in already reduced overbite and the extrusion of upper molars in high angle cases. Failing to prevent overeruption of second molars when biteplanes or functional appliances are used may also give rise to an AOB. 2-when High canines is engaged during alignment 3-Poor mechanics during fixed-appliance treatment may cause extrusion of the molar teeth or ‘hanging’ palatal cusps, which open the bite.

21. 7- Mouth breathing & Head posture: -- Mouth breathing (due to Nasal obstruction or Habit): This doesn’t play significant role in the development of AOB --Head posture :Related to breathing: mouth breathing  extension of head  stretch muscles  increase vertical dimension Studies have shown that when the nose is completely blocked, there is usually an immediate change of about 5° in the craniovertebral angle . The jaws move apart as much as the elevation of the maxilla because the head tips back by the depression of the mandible. This was described by Solow and Kreiborg as the soft tissue stretching hypothesis. International Journal of Paediatric Dentistry 2007

22. 8- Neurological disturbances: Neurological disorders contribute to the development of anterior open-bite. Gershater demonstrated a very high incidence (32.3%) of anterior open-bite in his survey of mentally retarded and emotionally disturbed children. This supports other studies where problems in controlling the tongue at rest or in function are encountered.

23. 9- Localized failure of development: In patients with cleft lip & alveolus ,although rarely it may occur for no apparent reasons. Pathological conditions may also present as anterior open-bite, such as in cleft palate, acromegaly .

24. 10 -Muscular Dystrophy The decrease in tonic muscle activity that occurs in muscular dystrophy allows the mandible to rotate downwards away from the rest of the facial skeleton, resulting in increased anterior facial height, a posterior growth rotation of the mandible, excessive eruption of the posterior teeth , narrowing of the maxillary arch and AOB that worsens with growth.

25. Posterior Open Bite A lateral open bite is occasionally seen in association with early extraction of first permanent molars, possibly occurring as a result of lateral tongue spread. Posterior open bite is also seen in cases with submergence of buccal segment teeth. An Introduction to Orthodontics , 2nd Edition 2001

26. There are two rare conditions which affect the eruption of the permanent buccal segment teeth : 1-Primary failure of eruption : this condition almost exclusively affects molar teeth and is of unknown aetiology . Although bone resorption above the unerupted tooth proceeds normally, the tooth itself appears to lack any eruptive potential . Extraction is the only treatment alternative. The aetiology is not understood. 2-Arrest of eruption : this also usually involves molar teeth. Affected teeth appear to erupt normally into occlusion, but then subsequently fail to keep pace with occlusal development. As growth of the rest of the dentition and alveolar processes continues, lack of movement of the affected tooth or teeth results in relative submergence . The aetiology is not understood and again the usual treatment is extraction of the affected tooth or teeth. An Introduction to Orthodontics , 2nd Edition 2001

27. 3-More rarely , posterior open bite is seen in association with unilateral condylar hyperplasia, which also results in facial asymmetry. If this problem is suspected, a bone scan will be required. If the scan indicates excessive cell division in the condylar head region, a condylectomy alone, or in combination with surgery to correct the resultant deformity, may be required.

28. Diagnosis of malocclusion with skeletal open bite

29. Diagnosis of malocclusion cases with skeletal open bite: Clinical examination Extraoral Increased lower facial height. Steep mandibular plane Antigonial notching Large interlabial gap. Less prominent chin Long face Upper lip less than 1/3 of the lower facial height. High lip line Gummy smile . Intraoral Anterior open bite extending posteriorly till premolar or molar areas Occlusal planes diverge Incisors extruded more than normal. Hypertrophic gingiva High narrow palatal vault Tongue thrusting during swallowing.

30. Cephalometric examination Maxilla Increased anterior dentoalveolar height ( incisal edge to palatal plane) Increased posterior dentoalveolar height (cusp tip to palatal plane) Mandible Short ramus (normal 51.3) Increased gonial angle Marked antigonial notching Increased FmA (normal 25) Narrow symphesis anteroposterior and long vertically Increased anterior dentoalveolar height Increased posterior dentoalveolar height Vertical relations Diverging SN, FH, occlusal , palatal, mandibular planes Maxillary occlusal plane steep upwards Mandibular occlusal plane steep downwards. Increased total facial hieght Increased lower facial height Reduced PFH

31. Diagnosis of malocclusion with dental open bite

32. Diagnosis of malocclusion cases with skeletal open bite : Clinical examination Extraoral There may be an increase in vertical height. Intraoral Charactreistic features related to the etiology Thumb sucking: proclined upper incisors, narrow upper arch, slightly deppressed lower incisors. Occlusion: open bite in incisor region molars and premolars are in contact

33. Cephalometric examination: Maxilla Upper incisors are proclined and may be spaced Dentoalveolar height at open bite region is reduced Dentoalveolar height otherwise increased Mandible Lower incisors retroclined , crowded, or may be proclined Dentoalveolar height at open bite region is normal or may be reduced Vertical relation Thumb sucking resulted in paltal plane and mandibular plane diverged away from each other at anterior region. Anteroposterior relation Thumb sucking restrains anterior development of mandible and encourage anterior development of maxilla increased incidence of Class ll relation.

34. ODI(Overbite Depth Indicator)(Kim 1974 ): American Journal of Orthodontics 1974; 65:586-611 The Angle A-B planes makes with the mandibular plane combined with the angle of palatal plane to FH . The angle formed by palatal plane and FH is either added (if + ve )to or subtracted (if - ve )from MP/A-B plane The angle is negative if palate is tipped down posteriorly or positive if the palatal plane is tipped down in front A value of less than 68 degrees is said to indicate over bite tendency .

35. 1-ODI(Overbite Depth Indicator) [Example]: ( MP-AB). ( Example : 76°). Measure the angle of the (FH), and (PP). In case of a positive value , write it in the corresponding positive rectangle , otherwise , write it in the corresponding negative rectangle ( Example : -3°) Combine these values to obtain the Overbite Depth Indicator (76°-3°=73°). In this example the ODI is 73 degrees,which is slightly lower than the norm (74.5° , 6°); howerver , the diference is 1.5°. Considering the standard deviation , it falls within the normal limit with a sligth tendency to be an openbite

36. Management of Anterior Open Bite

37. Management of AOB The key to the management of open bite tendency: 1- Eliminate the etiology. 2- Avoidance of extrusion of posterior teeth. 3- Intrusion of molars rather than extrusion of incisors. Treatment modalities: 1- No active treatment. 2- Habit breaker 3- Orthopedic appliances ( myofunctional therapy)& Removable appliances with bite blocks. 4- Fixed appliances. 5- Implants ( microscrew , miniplate ) 6- Surgery ( distraction osteogenisis & orthognathic surgery) 7- combination of two or more of the above.

38. Modalities of open bite correction Skeletal open bite in growing patients Goals of treatment are : vertical control of molars, vertical growth control, and this leads the mandible to rotate upword and forward Vertical control of molars : Direct : applying vertical forces directly to molars by using high pull headgear in maxilla, or cervical pull headgear in mandible Indirect : applying vertical forces via occlusion by using: Occlusal splint (3-4 mm in thickness) Active vertical corrector Vertical holding appliance Chin cup with vertical pull . combination

39. Treatment approach according to age During primary dentition Habit control Chin cup with vertical pull: redirect the growth forward and upward. During mixed dentition Chin cup with vertical pull+posterior bite plane High pull head gear+ acrylic splint Functional appliance + high pull head gear During permanent dentition Fixed orthodontic mechanotherapy : through molar intrusion, incisor extrusion or combination, and includes MEA ( multilooped edgewise apliance ) EOF (extra oral force )on molars TAD (temporary anchorage device). RCS (reverse curve of spee ) in upper arch

40. Extrusion arch wires Stepped arch wires Repelling magnets Vertical inter maxillary elastics extraction Skeletal open bite in non-growing patient Treated by fixed appliance mechano therapy Or orthognathic surgery

41. Treatment of dental open bite During primary dentition Habit control Elemination of deforming muscle activity During mixed dentition Habit control Posterior bite plane Myotherapy of the tongue During permanent dentition Fixed mechanotherapy

42. 1- No active treatment In this case treatment is aimed at relief of any crowding and alignment of the arches. This approach can be considered in the following situations (particularly if the AOB does not present a problem to the patient): 1-mild cases. 2-where the soft tissue environment is not favourable , for example here the lips are markedly incompetent and/or an endogenous tongue thrust is suspected. 3-when anterior open bite is transitional due to partially erupted incisor teeth 4-As first stage treatment in patients with sucking habits

43. 2-Habit breaker Proffit ’ s protocol Dent Update 2003; 30: 235-241

44. 2-Habit breaker Designs: Palatal crib (Removable or Fixed appliance) Tongue guard Quad helix Goal post Crib appliance prevents suction in palate

45. Goal Post

46. Quad helix function with tongue/thumb habit reminder Quad helix with more aggresive habit function

47. Vertical crib appliance traps tongue thrust Dillingham I

48. Mandibular tongue thrust appliance Dillingham Habit

49. Bead appliance to train tongue to proper position Palatal crib with a bead to train proper tongue position

50. 3-Orthopaedic & Removable appliances a-Posterior bite blocks, Twinblock , Elastic activator & Active vertical corrector b- Frankel -4 c- Extra-Oral traction: High pull headgear & Vertical pull chincup . d- palatal crib and high-pull chin cup therapy

51. Clark ’ s Twin-Block

52. a-Posterior bite blocks, Twinblock, Elastic activator & Active vertical corrector

53. Highpull headgear to the biteblocks may increase their efficiency. Where the AOB is associated with aClass II skeletal pattern, a Twin Block appliance with highpull headgear can be used to correct the anteroposterior discrepancy whilst controlling the vertical dimension. Dent Update 2003; 30: 235-241

54. Elastic Activator A modified activator is used treatment of open bite cases. The intermaxillary acrylic of the lateral occlusal zones is replaced by elastic rubber tubes. By stimulating orthopaedic gymnastics (chewing gum effect), the elastic activator intrudes upper and lower posterior teeth. A noticeable counterclockwise rotation of the mandible was accomplished by a decrease of the gonial angle. a-Posterior bite blocks, Twinblock , Elastic activator & Active vertical corrector British Journal of Orthodontics/Vol. 26/1999/89 – 92

55. Elastic Activator a-Posterior bite blocks, Twinblock , Elastic activator & Active vertical corrector

56. Elastic Activator a-Posterior bite blocks, Twinblock, Elastic activator & Active vertical corrector

57. a-Posterior bite blocks, Twinblock , Elastic activator & Active vertical corrector Kalra , Burstone and Nanda (1989) have suggested that magnets may be beneficial in treating anterior open bites by: • intruding upper and lower posterior teeth so as to allow mandibular autorotation and • distracting the condyle downwards and forwards to allow compensatory condylar growth which would again favour mandibular autorotation Magnet-AVC (Active Vertical Corrector)

58. Energized bite blocks. Energy is obtained from repelling force of samarium cobalt magnets hermetically sealed In S.S. capsule. a-Posterior bite blocks, Twinblock , Elastic activator & Active vertical corrector

59. AVC Mode of Action: Reciprocal intrusion of maxillary & mandibular teeth which result in autorotation of mandible & overbite correction Duration of wear  12 hrs /day Force level: -700 gm per unit with 0 gap -In open bite cases no 0 gap is present ,so force 600-650 gm per unit -Magnets are placed over the teeth to be corrected. Reported side effect: posterior crossbite owing to the lateral force component of the repelling magnets. a-Posterior bite blocks, Twinblock , Elastic activator & Active vertical corrector

60. b- Functional Regulator Appliance Frankel (FR-4) These are thought to be effective where the open bite is at least partly due to faulty postural activity of the orofacial musculature. The FR-4 works by allowing vertical eruption of upper and lower incisors and retraction of the maxillary incisors, and some authors have reported a change in mandibular rotation from a downward and backward direction to upwards and forwards.

61. The use of other functional appliances, open-bite bionators , kinators , in the correction of anterior open-bites have also been mentioned by some authors.

62. c- Highpull Headgear Highpull headgear applied to the maxillary molar teeth and worn for 14 hours per day has been used to inhibit eruption of the posterior teeth and hence limit vertical growth. Headgear can be applied directly to the upper molar bands of a fixed appliance or use in conjunction with a functional appliance or an upper removable appliance such as a maxillary intrusion splint . This form of treatment is based on the assumption that over- development of the posterior maxilla is responsible for the deformity.

63. c- Highpull Headgear Functional appliances used for Class II maloclusions with increased vertical proportions include the van Beek appliance ,it incorporate high-pull headgear and buccal capping. In many cases fixed appliances are then used to complete arch alignment, together with extractions if indicated.

64. c-Vertical Pull Chincup Vertical pull chincup therapy has been used to limit excessive vertical growth. Pearson reported on 20 growing patients with backward rotational tendencies treated by the extraction of four first premolars, chincup therapy and fixed appliances. He showed that chincup therapy was effective in reducing the angle between the maxillary and mandibular planes and at closing all anterior open bites.

65. c-Vertical Pull Chincup Mandibular autorotation was attributed to reduction in the ‘wedging’ effect by premolar extraction, retardation of eruption of posterior teeth and redirection of condylar growth. However, chincup therapy generally has poor compliance rates and there is some concern that it may cause condylar damage.

66. d-palatal crib and high-pull chin cup therapy Twelve months treatment with a palatal crib and chin cup therapy resulted in the following changes: 1. Statistically significant extrusion of the incisors, as well as an increase in overbite and exposure of the maxillary incisors. 2. Greater uprighting and retrusion of the incisors, with a statistically significant difference compared with the controls. 3. No statistically significant changes in the level of eruption of the molars, with no real or relative intrusion of these teeth. 4. No statistically significant skeletal changes, or significant growth inhibition of LAFH, closure of the mandibular plane angle or SNA/SNB modification.

67. HIERARCHY OF EFFECTIVENESS IN LONG-FACE CLASS II TREATMENT

68. 4- Fixed appliances

69. 1- Intermaxillary elastics : Anterior open bites can be closed using fixed appliances and vertical intermaxillary elastics to extrude the anterior teeth. This may be combined with a transpalatal arch (TPA) and highpull headgear to limit vertical development of the maxillary molar teeth . The TPA functions to prevent buccal rolling of the first molars, which could cause the bite to be propped open on their palatal cusps. Use of anterior elastics may be successful in patients in whom a digit-sucking habit has artificially inhibited eruption, but is unlikely to work if the aetiology is primarily skeletal.

70. Traditionally, vertical elastics have been used for open bite closure. Inter arch mechanics with vertical elastics are indicated in anterior open bite cases with occlusal planes diverging anteriorly. Vertical elastics from the lower incisors to the upper incisors result in a consistent force system of equal and opposite forces. Force system of anterior vertical elastics (equal and opposite forces).

71. Although vertical elastics are a common method For incisor extrusion, certain problems are inherent in this type of treatment . First, response to this therapy varies greatly among patients due to poor control of the force magnitude and different degrees of compliance. Second , specific goals defined in the treatment plan ( occlusal plane, incisor position objectives) can not be predictably achieved because good mechanical control is difficult wilh indiscriminate use of elastics.

72. Correction of Open Bite with Elastics and Rectangular NiTi Wires

73. JCO 1991 Nov (697-698)

74. Where anterior open bites are associated with proclined incisors, such as some bimaxillary proclination cases and Class II/I malocclusions, retraction of the incisors results in an extrusive movement, as the crown is rotated around the centre of rotation of the tooth. This reduces/eliminates the open bite. Stability depends on the tongue adapting to a new functional position after treatment. Dent Update 2003; 30: 235-241 2-Incisors retraction:

75. 3. Extrusion Arches Extrusion arches are efficient tools used to correct upper and lower occlusal planes that diverge anterior to the first premolars. These archwires are indicated (1) When spontaneous correction of an anterior open bite does not occur following tongue crib therapy. ( 2) When a constant extrusive force is desired in the anterior teeth with minimal posterior side effects. ( 3) In noncompliant patients who will not wear anterior vertical elastics.

76. The extrusion arch is a one-couple force system that applies a single extrusive force in the anterior teeth, and a tip forward moment and intrusive force to the posterior segment. Often, the tip forward moment is undesirable. Extrusion arch force system; a one couple system with ananterior extrusive and a posterior intrusive force. The couple on the molar produces a tip forward moment.

77. First, to negate this side effect, a buccal segment from the upper first molar to the first premolar is added. Second , the magnitude of the extrusive force should be kept low (extrusion of the incisors requires very light forces) to maintain the posterior moment at a minimal level. Finally , adding vertical elastics off the posterior segment to negate this tip forward moment is also helpful. Vertical elastic added to the upper buccal segment to negate the tip forward tendency produced by the couple system in the extrusion arch.

78. The extrusive force of an extrusion arch applied to divergent occlusal planes anterior to the premolars is favorable, especially if the upper incisors are flared. As this force is applied labially to the center of resistance of" the incisors, the moment of the force will produce an uprighting movement (crown lingual). Effects of the anterior force of the extrusion arch on the upper incisors. The applied force at the bracket will produce at the center of resistance of the incisors a clockwise moment plus an extrusive force of equal magnitude.

79. This figure shows a patient with anterior open bite that was corrected using upper and lower extrusion arches Progress of a patient with extrusion arches on the upper and lower dentition. A Frontal view on smile. Only 50% of incisor show on smile. Patient will benefit esthetically from upper incisor extrusion, B-D Preoperative intraoral photographs showing a 3 mm negative overbite and an occlusal plane diverging anteriorly from the first premolars.

80. E-G Upper extrusion arch with buccal segments to prevent molar tip forward. The lower extrusion arch is tied to the four incisors H-J Good anterior open bite correction with maintenance of the vertical relationship on the buccal segments..

81. Upper extrusion arch used in conjunction with a light nickel-titanium base arch. The extrusion arch maintains the anterior vertical relationship as the canines are brought into the arch. Esthetically a good smile arc and approximately 95% incisor display on smile are achieved.

82. 4- Extractions for Open Bite Closure Different types of extraction patterns have been suggested to correct anterior open bites. These extraction patterns include extracting: the second molars, first molars, second premolars, or first premolars. The various extraction modalities for the correction of an open bite are tailored towards extruding the anterior segment, moving the posterior teeth anteriorly (wedge effect). or a combination of the two.

83. Second Molar Extractions The extraction of second molars has been suggested as a viable option in patients who have an anterior open bite with contact only on these teeth, and divergent occlusal planes (wedge effect). Although this is a feasible option, the magnitude of the occlusal plane divergence is the limiting factor in full overbite correction.

84. Anterior open bite with occlusal planes diverging from the second molars anteriorly. All second molars are extracted for correction of the open bite. The magnitude of the open bite correction is dependent on the angle of divergence of the upper and lower occlusal planes. Full correction of the anterior open bite may not be obtained in extremely divergent occlusal planes.

85. A potential problem, depending on the age of the patient, is the necessary continuous monitoring of the third molars until full eruption and correct positioning in the arch is achieved. However, this method provides an advantage over the other extraction patterns since no space closure is needed and vertical forces are not likely to be generated (see section on space closure in premolar extract ions below). Interestingly, patients who present with this anterior open bite pattern (divergent occlusal planes with second molars only contacting) are generally viewed as surgical patients.

86. First Molar Extractions First molar extractions are typically performed only if these teeth are compromised by extensive decay. In theory, this treatment alternative should contribute to anterior open bite closure, and it has been reported that this extraction pattern maintains or slightly reduces the vertical skeletal relationships. However , in the majority of patients, the second molar replaces the first molar and the anterior open bite is not resolved. As the molar is protracted into the extraction space, extrusion of the distal aspect usually results due to poor mechanics, thereby increasing or maintaining the anterior open bite

87. Overall, if this extraction option is considered, space closure mechanics is the deciding factor in the success of the overbite correction, This treatment alternative would be most effective if proper timing is considered. If the second molars have not erupted, and if the patient is only contacting on the first molars, extraction of the first molars would eliminate the increased vertical height and the second molars would only be able to erupt up to the new established vertical height

88. Extractions of Premolars Extractions of the first or second premolars are the most commonly considered procedures for the treatment of anterior open bites associated with crowding and/or over jet. The decision between extracting the first or second premolars depends on the amount of incisor retraction. in these patients the open bite is closed with the help of extrusion of the anterior segment instead of the " wedge effect." Controlled tipping of the upper incisors produced by a distal force results in extrusion of the incisal edge and reduction of the amount of labial incisor inclination.

89. This treatment alternative works very well in patients with occlusal planes that diverge anteriorly from the first or second premolar. The mechanics are easier when the anterior teeth are flared (as is usually the case with this type of occlusal plane divergence ). A single distal force (ideally controlled tipping) will produce lingual tipping of the incisor crowns. Since the center of rotation is close to the apex, the net effect is extrusion and retraction of the incisors to close the bite .

90. Biomechanics of Space Closure in Open Bite Group A Space Closure Group A space closure is most difficult to perform in anterior open bite patients if intraoral anchorage is desired. The use of differential moments to maintain anchorage in this force system results in a large moment and an extrusive force posteriorly. Differential moment force system in group A space closure is unfavorable for anterior open bite correction. Vertical forces tend to accentuate the open bite.

91. Anteriorly a smaller moment and an intrusive force are generated. This force system is highly undesirable in an open bite patient. This figure shows that the vertical forces are antagonistic with this space closure strategy.

92. An alternative would be to use a single couple system (intrusion arch) where a couple is created at the level of the molar and an additional base arch (0.018 SS) is placed for canine sliding mechanics. The base arch would minimize the intrusive force in the anterior teeth while the intrusion arch would contribute to anchorage in the posterior end.

93. Group B Space Closure Mechanically, group B space closure is the simplest. No vertical forces are generated and only two equal and opposite moments are needed. Careful monitoring is essential to ensure that equal moment/force ratios are delivered to the anterior and posterior segments. Mechanics for group B anchorage with equal and opposite moments is favorable in anterior open bite patients since no vertical forces are generated. Adequate mement /force ratios of 10/1 are desired to prevent tipping of the posterior segments that may accentuate the open bite.

94. If a high force magnitude in relation to the moment is delivered in the posterior end, excessive crown lipping will result, extruding the distal cusps of the molar, and possibly increasing the open bite. Patient showing tipping of the lower first molar and extrusion of the distal marginal ridge. Lateral open bite is developed.

95. Group C Space Closure Group C space closure mechanics is the most favorable for anterior open bite correction. Intraoral anchorage by means of differential moments obtains a consistent force system. Mechanics tor group C space closure are the most favorable for open bite correction. Vertical forces are consistent with open bite correction in the anterior (extrusive) and posterior (intrusive) segments

96. This Figure shows a larger moment in the anterior segment and an extrusive force that will maintain the anteroposterior incisor position. A smaller moment in the posterior and an intrusive force will allow this segment to tip as a mesial force is applied.

97. Anterior open bite closure by molar extractions and group C mechanics. A Initial smile view showing an adequate amount of incisor show. B Profile view showing a retrognathic mandible and long facial height .

98. C-E Preoperative photographs showing molar-to-molar open bite. All first molars have significant carious decay, except for the upper left.

99. Initial lateral cephalogram showing a retrognathic mandible with a skeletal anterior open bite and divergent occlusal planes from molar to molar.

100. Differential moment approach for group C space closure. A19 x 25 stainless steel base archwire from 5 to 5 is used as the anchor unit to protract the lower 7s after extraction of the carious first molars . Sectional 17 x 25 CNA wires with a V-bend offset anteriorly (Class V geometry) generate a larger anterior moment and extrusive force , and a smaller moment and intrusive force posteriorly. The sectional wire is connected to the base archwire by a vertical tube soldered to a horizontal tube.

101. Upper left first premolar extracted and upper canines brought into the arch using equal and opposite forces by means of an intermaxillary elastic.

102. Smile view showing unaltered incisor display and open bite correction through molar vertical control as the second molars were protracted S Profile view shows the positive skeletofacial change with the mandibular autorotation and reduction of the anterior facial height.

103. Rationale behind choosing this mechanics: Palatal plane is tipped upward & forward with teeth tipped mesially . Because of this ,treatment should be directed toward extracting the terminal molars and distal tipping of the dentition . 5- Multiloop Edgewise Arch Wire(MEAW) (Kim mechanics)

104. This is usually achieved using multi-loop edgewise archwires made of 0.016× 0.022 S.S. wire. 5-L-shaped loops /side starting from between lateral incisors and canines and moving distally . Vertically ,loops should be 2-3 mm and horizontally it should be 5-mm except in molar region where this increased to 8-mm

105. Tip-back of 3-5 degrees are placed on each loop to place a curve of spee (CS) on upper and reverse curve of spee (RCS) in lower arches .3/16” or 1/8” heavy elastics anteriorly will counter act the curve of spee in upper and RCS in lower.

106. Although this method has proved successful, excellent compliance with elastic wear is essential and long-term stability has yet to be determined.

107. More recently, the use of reverse curve nickel-titanium archwire , instead of multiloop wires, had worked well. 0.016× 0.022 NiTi (reverse curve of spee RCS) in lower and (accentuated CS) in upper arch. Heavy anterior elastics(3/16” 4.5 Oz) in canine region. At some stage ,molar become out of contact , then flat 0.016× 0.022 S.S. wire is inserted and continue with anterior elastics. 6-Recent modification of Kim mechanics

108. Effects of MEAW & CS 1- Retraction and extrusion of anterior teeth 2- Up-righting & intrusion of posterior teeth 3- Few skeletal changes

109. The RMI appliance provided effective bite closure and favorable dentofacial changes for nonsurgical open bite treatment in growing patients . This method could be regarded as a safe and non-compliance alternative for early intervention of skeletal open bite correction. 7-Rapid Molar Intruder(RMI) Appliance in Growing Individuals

110. 5-Microscrews & Miniplates

111. On the upper arch, in the event that one single posterior tooth requires intrusion, two miniimplants should be inserted, one buccally and one palatally , the former on the mesial and the latter on the distal region.The mini-implants, if placed accordingly, will provide a controlled vertical movement without undesirable inclinations. Force can be applied either by extending elastics between the mini-implants and the orthodontic accessories installed on the buccal and palatal surfaces of the tooth in question. 5-Microscrews

112. or by extending elastics directly on the tooth’s occlusal surface and connecting one mini-implant to the other. In this case, caution should be exercised not to allow the force action line to cause the elastic to drift towards the mesial or distal region, which might lead the dental unit which is undergoing intrusion to tip.

113. Intrusion of groups of teeth In the event of a group of teeth requiring intrusion, the whole group should be handled all together in a group. Brackets can be bonded to the buccal and palatal surfaces of the teeth involved and connected with segmented archwires ; an orthodontic archwire segment can be bonded directly to the buccal and/or palatal surfaces; alternatively, a single orthodontic archwire segment can be attached to the occlusal surfaces, provided it does not cause any interference

114. The arch wire segments attached to brackets on the buccal and palatal regions, activation can be achieved using elastic on the archwire attached to the arch segments.

115. Arch wire segments attached to brackets on the buccal and palatal regions with an elastic chain running alongside the occlusal surface for activation

116. Arch wire segments Bonded directly to buccal and lingual surfaces while activation was done with an elastic chain running alongside the occlusal surface

117. An arch wire attached to the occlusal surface while activation was done with an elastic chain running alongside the occlusal surface

118. Mandibular Molar Intrusion

119. 5-Miniplates Titanium miniplates , offer stable skeletal anchorage for intruding molars. True intrusion of molars can be accomplished in adults. The occlusal plane angle of open-bite patients changes accordingly. Anterior open bites can be closed orthodontically by intruding posterior teeth, resulting in reduced anterior vertical face height, decreased mandibular plane angle, and counterclockwise rotation of the mandible.

120. American Journal of Orthodontics and Dentofacial Orthopedics December 2002

121. A-Microscrews & Miniplates American Journal of Orthodontics and Dentofacial Orthopedics December 2002

122. SURGERY

123. A-Segmental alveolar distraction for the correction of unilateral open-bite caused by multiple ankylosed teeth B- Tongue Reduction. C- Orthognathic Surgery.