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Anterior Open Bite etiology and differential diagnosis

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A brief discription of the anterior open bite malocclusion, its etiology and differential diagnosis

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Anterior Open Bite etiology and differential diagnosis

  1. 1. Anterior Open Bite Etiology and Differential Diagnosis Dr.Marwan Mouakeh, Consultant Orthodontist Academic Adviser, Al-Hokail Polyclinic – Khobar ( KSA)
  2. 2.  OPEN BITE – Definition • The term was coined by Caravelli in 1842 as a distinct form of malocclusion. • Anterior Open Bite ( AOB) may be defined as the lack of incisal contact between anterior teeth when the mandible is brought into full closure .
  3. 3.  OPEN BITE – Definition • Anterior Open Bite ( AOB) may be also defined as : the absence of vertical overlap of the lower incisors by the upper incisors ,when the posterior teeth are in full occlusion . • AOB can occur in all types of malocclusion.
  4. 4. Subtelny and Sakuda Open Bite is a deviation in the vertical relationship of the maxillary and mandibular dental arches. It is characterized by a definite lack of contact , in the vertical direction, between opposing segments of teeth.  OPEN BITE – Definition
  5. 5. Anterior Open Bite •The prevalence of dental open bites in the U.S Children is approximately 16.5% in the black population and 3.5% in the white population. • The prevalence of simple anterior open bite decreases until adolescence . Worms et al , 1971  Prevalence Kelly et al,1973 • Prevalence of AOB in the population ranges from 1.5% to 11% ( Zuroff et al, AJO-DO March 2010 )
  6. 6.  Prevalence • Varies among races & with dental age - At 6 years, 4.2% of children present with anterior open bite, whereas at age 14 the prevalence decreases to 2% . - Negative overbite ( > -2mm) occurs less than 1% of the US population . - AOB is 5 times more prevalent in Blacks (16.5% )than in Whites(3.5% ) or Hispanics . Kelly et al, NCHS 1973 Anterior Open Bite
  7. 7.  Prevalence •Open bites occur less than deep bites • The Demand for treatment is approximately 17% . Anterior Open Bite Contemporary Orthodontics 4th edition , Proffit,Fields and Sarver. 2007
  8. 8. Prevalence of Anterior Open Bite Malocclusion in a sample of Saudi Orthodontic Patients A Pilot study
  9. 9. Materials and Methods • A pilot study on a sample of Orthodontic Population • Evaluation of 500 Cephalometric Radiographs and Tracings • All subjects were Adults of Saudi origin • Isolation of the anterior open bite (AOB) patients on the basis of negative overbite . Prevalence of Anterior Open Bite Malocclusion in a sample of Saudi Orthodontic Patients
  10. 10.  Results • Number of AOB cases = 48 (out of 500) or a percentage of 9.6% »Males = 20 (41.7 %) »Females = 28 (58.3 %) Prevalence of Anterior Open Bite Malocclusion in a sample of Saudi Orthodontic Patients
  11. 11. Classification of Anterior Open Bite
  12. 12. Classification of Open Bite ( Worms,Meskin,and Isaacson )  Simple OB : from canine to canine  Compound OB: from premolar to premolar  Infantile OB : from molar to molar.
  13. 13. Classification of Open Bite ( Cooke,1981)  Skeletal OB  Habit or Dental OB  Abnormal Tongue Function OB  Iatrogenic OB  Pathological OB
  14. 14.  Classification of AOB  Dental  Dento-alveolar  Skeletal abnormal eruption of the incisors change in the vertical growth of the alveolar component unfavorable vertical growth pattern
  15. 15. • Dentoalveolar with alteration in normal eruption of anterior teeth( due to non-nutritive sucking habits ). • Skeletal with long face caused by clockwise(backward ) rotation of the mandible . • Skeletal caused by skeletal deformation such as tipping of the maxilla and diversion of the gonial angle of the mandible .  Classification of Open Bite (K.Yamaguchi ) • K.Yamaguchi , in Nanda : Current Therapy in Orthodontics – 2010
  16. 16.  Classification and Types of Anterior Open Bite Dentoalveolar SkeletalSkeletal + • K.Yamaguchi , in Nanda : Current Therapy in Orthodontics -2010
  17. 17.  Restricted to the anterior teeth Normal facial &skeletal features  Dentoalveolar Anterior Open Bite  Classification and Types of Anterior Open Bite
  18. 18.  Skeletal Anterior Open Bite  Backward and downward rotation of the mandible  Classification and Types of Anterior Open Bite
  19. 19.  Skeletal Anterior Open Bite  Extending to the buccal teeth Due to skeletal abnormality  Associated with facial vertical disproportion .  Classification and Types of Anterior Open Bite
  20. 20.  Skeletal Anterior Open Bite Excessive vertical growth of posterior maxillary and mandibular regions .  Classification and Types of Anterior Open Bite
  21. 21. The etiology of anterior open bite malocclusion is Multifactorial :  Genetic and Hereditary factors  Anatomic factors  Environmental factors Etiology of Anterior Open Bite
  22. 22. Genetic Factors Environmental Factors Lower facial height is under strong genetic influence. Etiology of Anterior Open Bite Abnormal functions and altered soft tissues posture.
  23. 23. • Sbtelny & Sakuda (1964) • The main cause of Skeletal Open Bite is an unfavorable growth pattern with divergent basal bones . Etiology of Anterior Open Bite  Abnormal skeletal size  Abnormal vertical growth pattern  Increased tongue size .  Genetic and Anatomic Factors
  24. 24. Etiology of Anterior Open Bite  Genetic and Anatomic Factors Abnormal skeletal growth pattern of the maxilla & mandible, particularly the lower jaw.  Skeletal Open Bite (Sassouni)  Backward Mandibular Growth Rotation ( Bjork)  Clockwise Rotation of the Mandible (Jarabak)  Dolichofacial Pattern ( Ricketts)  Hypedivergent Facial Pattern ( Schudy )  Terminology
  25. 25.  Genetic and Anatomic Factors •Unfavorable Growth Potential - Steepness of mandibular plane - Increased gonial angle - Short mandibular ramus - Increased anterior lower face height - Backward rotation of the mandible. Etiology of Anterior Open Bite
  26. 26. 9,6y 24,6 y Bjørk & Skieller,1983 •Backward Rotation Arne Bjørk 1911-1996)  Growth Rotations
  27. 27. •Inclination of the condylar head •Curvature of the mandibular canal •Shape of the lower border of the mandible •Inclination of the symphysis • Anterior lower facial height •Inter incisal angle •Inter premolar , inter molar angle. Structural signs of extreme Growth Rotations
  28. 28.  Genetic and Anatomic Factors Tongue size and Posture - Macroglossia - Lower tongue posture (at rest) Etiology of Anterior Open Bite
  29. 29. Genetic and Anatomic Factors Etiology of Anterior Open Bite Muscular dystrophy Neuromuscular deficiencies
  30. 30. Etiology of Anterior Open Bite Genetic and Anatomic Factors •The decrease in tonic muscle activity that occurs in muscular dystrophy allows the mandible to rotate downwards resulting in increased anterior facial height & posterior growth rotation of the mandible. Muscular dystrophy
  31. 31. Etiology of Anterior Open Bite • Amelogensis imperfecta
  32. 32. Genetic and Anatomic Factors  Mandibular condyle resorption - Local causes : example ( osteoarthritis , avascular necrosis ,traumatic injuries…) - Systemic causes : example ( rheumatoid arthritis …) Etiology of Anterior Open Bite
  33. 33. Idiopathic condylar resorption  Most common in TMD adolescent patients ( particularly in females )  Affects mandibular condyles bilaterally  No obvious etiology ( DD Without reduction, joint hypermobility , trauma , parafunctional activity, decreased levels of estrogen….).
  34. 34. •Idiopathic condylar resorption Etiology of Anterior Open Bite - may induce a “sudden open bite “
  35. 35. •Idiopathic condylar resorption may induce a “sudden open bite “ Etiology of Anterior Open Bite
  36. 36. Etiology of Anterior Open Bite Genetic Factors Environmental Factors •Anterior (and low) tongue posture at rest • Prolonged thumb or finger sucking • Tongue thrust • Mouth breathing • Atypical deglutition • Weak masticatory muscle forces
  37. 37. Environmental Factors Etiology of Anterior Open Bite
  38. 38. Environmental Factors  Habits - Pacifier and Thumb sucking habits - Tongue thrust - Infantile deglutition ( swallowing ) Etiology of Anterior Open Bite
  39. 39. Etiology of Anterior Open Bite Environmental Factors •Thumb & Pacifier sucking habits
  40. 40. •Pacifier and Thumb-sucking habits are strong etiologic factors for open-bite malocclusion . Etiology of Anterior Open Bite Environmental Factors G. Janson &F.Valarelli , Open –Bite Malocclusion Treatment and Stability . 2014
  41. 41. •Anterior open bite caused by the use of pacifier is characterized by being restricted to the anterior region of the dental arches and circular . Etiology of Anterior Open Bite G. Janson &F.Valarelli , Open –Bite Malocclusion Treatment and Stability . 2014
  42. 42. Environmental Factors  Non-Nutritive Sucking Habits Etiology of Anterior Open Bite
  43. 43. Environmental Factors Etiology of Anterior Open Bite • Thumb and Finger Sucking (Non-Nutritive Sucking ) - Major cause of AOB in young children - 10% -15% of children tend to continue sucking habit after age 10 .
  44. 44. •Thumb-sucking habit characteristically causes labial inclination of maxillary incisors and lingual inclination of mandibular incisors . Environmental Factors Etiology of Anterior Open Bite
  45. 45. Environmental Factors  Non-Nutritive Sucking Habits Etiology of Anterior Open Bite Asymmetric AOB
  46. 46. Environmental Factors • Abnormal tongue function Etiology of Anterior Open Bite Anterior Tongue Thrust , Tongue Sucking
  47. 47. Environmental Factors Etiology of Anterior Open Bite Airway obstructions ( Mouth Breathing ) - Enlarged adenoids and tonsils - Swollen nasal turbinates - Deviated nasal septum - Inflammed nasal mucosa
  48. 48. Upper Airway Obstruction Mouth Breathing Low Tongue & Mandibular Posture Supra-eruption of Posterior Teeth •Enlarged Adenoids •Enlarged Tonsils •Deviated nasal septum •Swollen nasal turbinates
  49. 49.  No clear –cut relationship between Breathing and Malocclusion :  Total nasal obstruction is highly likely alter the pattern of growth and lead to malocclusion in experimental animals and humans But , the majority of individuals with long face have no evident nasal obstruction . Etiology of Anterior Open Bite
  50. 50. 11 yrs. 17 yrs. • Airway Obstruction Great controversy regarding the real effect on facial growth pattern •Decrease in adenoid volume and enhancement of “ airways patency ” with growth and maturation.
  51. 51. Low and anterior tongue posture may be considered as the key etiological factor in AOB . • Abnormal tongue posture Etiology of Anterior Open Bite
  52. 52.  If Postural change of the tongue lasts long ,  Maxillary arch becomes narrow  Molars passively super-erupt  Mandible rotates clock-wise  Anterior facial height increases  Overjet increases
  53. 53. Etiology of Anterior Open Bite • Abnormal tongue posture  Enlarged tonsils Low & forward tongue positioning
  54. 54. Low and anterior tongue posture may cause: - infra-position of the anterior teeth - over-eruption of posterior teeth - upper arch constriction . • Abnormal tongue posture Etiology of Anterior Open Bite
  55. 55. Etiological Factors and Morphological Features of Open Bite • K.Yamaguchi , in Nanda : Current Therapy in Orthodontics
  56. 56. Etiology of Anterior Open Bite Environmental Factors •Disturbance in the eruption of the teeth & alveolar growth due to trauma causing ankylosis of anterior teeth .
  57. 57. Etiology of Anterior Open Bite Environmental Factors •Severe crowding of anterior teeth • Arrested tooth eruption (Idiopathic or Iatrogenic )
  58. 58. •Iatrogenic Open Bite: In the consequence of orthodontic therapy where poor mechanics can cause extrusion of the molar teeth or hanging palatal cusps which open the bite. Failing to prevent over-eruption of second molars when biteplates or functional appliances are used will give rise to an open bite. Etiology of Anterior Open Bite Environmental Factors
  59. 59. Etiology of Anterior Open Bite Environmental Factors •Iatrogenic Open Bite
  60. 60. •Temporomansibular Pain & Dysfunction may cause resorption of the mandibular condyle which in turn induce open bite malocclusion. • TMD problems and Open bite make bite force weaker. • The weaker is the bite force , the severer becomes the open bite .This makes a vicious cycle. JW Han & TW Kim,2006 Etiology of Anterior Open Bite
  61. 61. • JW Han & TW Kim,2006 Etiopathogenesis of open bite in TM Dysfunctions
  62. 62. • Some Etiological Factors of Open bite Malocclusions • JW Han & TW Kim,2006
  63. 63. Anterior Open Bite Diagnostic Considerations
  64. 64. Dentoalveolar Open Bite •Main Feature •Proclined upper anterior teeth •Lack of overlap between the upper and lower anterior teeth. •Narrow Maxillary Arch (Low Tongue Posture)
  65. 65. Dentoalveolar Open Bite Main Features • Normal facial proportions • Associated with anterior tongue thrust during swallowing and lisping .
  66. 66. Dentoalveolar Open Bite •Main Cephalometric Feature •Proclined upper anterior teeth •Infraposition of the anterior teeth • Reduced anterior dentoalveolar height
  67. 67.  Characteristics of Dental Open Bite  Normal craniofacial pattern  Proclined incisors  Undererupted anterior teeth  Normal or slightly excessive molar height  Divergent upper and lower occlusal planes  Absence of remarkable cephalometric findings  Thumb or finger sucking habits  Tongue thrusting habit
  68. 68.  Skeletal Open Bite
  69. 69.  Main Clinical Characteristics Skeletal Open Bite • Excessive anterior face height , particularly in the lower third • Lip incompetence (interlabial gap > 4mm) • Anterior open bite ( not always) •Tendency to Class II malocclusion with mandibular deficiency • Tendency to posterior cross bite due to narrow maxilla.
  70. 70. • Main Facial and Occlusal Features • Lip Incompetency • Large Interlabial gap at rest Key soft tissue finding  Skeletal Open Bite
  71. 71.  Skeletal Anterior Open Bite Severe &extended open bite including the posterior teeth.
  72. 72. •Dentoalveolar OB ,vs, Skeletal OB  Divergence of occlusal planes Dentoalveolar Open Bite Skeletal Open Bite
  73. 73.  Skeletal AOB : Occlusal planes generally diverge from the 1st molar anteriorly Occlusal characteristics of Skeletal and Dental Open Bites  Dental AOB : Occlusal planes generally diverge from the premolar anteriorly
  74. 74. Cephalometric Characteristics Skeletal Open Bite
  75. 75. • Proportional discrepancy between anterior and posterior facial heights  Mechanism of Skeletal Open Bite (K.Yamaguchi ) •Any elongation of posterior teeth will induce a clockwise rotation of the mandible + +
  76. 76.  Main Cephalometric Characteristics Skeletal Open Bite • Increased anterior face height and decreased posterior face height • Steep mandibular plane with short ramus • Increased anterior lower facial height • Upper tip of the palatal plane • Excessive eruption of maxillary posterior teeth .
  77. 77. Common Cephalometric Indicators for Skeletal Open Bite • SN- MP • FH-MP • PP-MP • Y-axis angle • Gonial angle  Sagittal Angles •Lower Gonial Angle LGA FH SN MP PPY-Axis
  78. 78. •Mandibular Plane angle > 36⁰ Key skeletal finding associated with anterior skeletal open bite cases . SN/ MP > 36⁰  Skeletal Open Bite
  79. 79. •Anterior face height : increased •Ratio : PFH / AFH < 62% (Jarabak ) • Ratio : AUFH / AFH < 45% •Ratio : ALFH / AFH > 55% Me / Skeletal Open Bite Main Cephalometric Indicators AUFH / ALFH < 70% - 65% ( Nahoum ,1975)
  80. 80. Kim, 1974 Overbite Depth Indicator (ODI) = ( A-B plane/ MP )⁰ + ( FH/PP)⁰ Mean = 74.5⁰ ± 6⁰ Skeletal Open Bite
  81. 81.  Overbite Depth Indicator (ODI) • ODI ≤ 68 ⁰ Skeletal OB Tendency Skeletal Open Bite A-B Plane FH MP PP
  82. 82. •Structural signs of mandibular growth rotation demonstrated on two craniums one with basal deep bite and one with basal open bite.  A . Bjork,1969
  83. 83. •Morphological signs of backward mandibular growth rotation ( Bjork , Skieller and Linde-Hansen) •Anterior facial height Increased •Inclination of lower border Notched of the mandible •Inclination of symphysis Slopes forward •Inclination of the condyle Straight or slopes back •Curvature of mandibular Straight canal •Intermolar angle Acute •Internincisal angle Acute Backward rotationMorphological sign
  84. 84. • Sassouni, 1969 Classification of Facial Types
  85. 85. •Ratio : PFH / AFH •Ratio : UFH / LFH •SN/ GoGn angle •Gonial angle •SN / PP angle • PP/ GoGn angle The angles and ratios remained relatively constant with age. T J Cangialosi, Cephalometric Features of Skeletal Open Bite
  86. 86. • Result showed a significant increase in :  AFH  MP angle  Gonial angle  Y-Axis angle  Mandibular occlusal plane/SN angle  Interincisal angle  A significant decrease in maxillary length , and retruded position of both the maxilla and the mandible relative to SN plane .  Cephalometric features of anterior open bite SM Taibah & RM Feteih , 2007 •Cephalometric evaluation of 111 ( 58 females,53 males ) subjects of Saudi origin with anterior open bite .
  87. 87.  No Significant differences in all dental heights between open-bite and control subjects.  Open bite malocclusion is largely due to changes in the skeletal pattern .  Cephalometric features of anterior open bite SM Taibah & RM Feteih , 2007
  88. 88. Open bite malocclusion: Analysis of the underlying components M. El-Dawlatly et al, Dent Oral Craniofac Res,2015 The Percentages of occurrence of all components in open bite malocclusion.
  89. 89. The Percentages of occurrence of skeletal components in open bite malocclusion. Open bite malocclusion: Analysis of the underlying components M. El-Dawlatly et al, Dent Oral Craniofac Res,2015
  90. 90. The Percentages of occurrence of dental components in open bite malocclusion. Open bite malocclusion: Analysis of the underlying components M. El-Dawlatly et al, Dent Oral Craniofac Res,2015
  91. 91. Open bite malocclusion: Analysis of the underlying components M. El-Dawlatly et al, Dent Oral Craniofac Res,2015  High contribution of skeletal factors in the development of open bite malocclusion.  The increased downward and backward rotation of the mandible is the highest sharing skeletal variable .  The reverse curve of Spee and the proclination of the upper incisors are the highest sharing dental factors in open bite malocclusion. Conclusions
  92. 92.  Skeletal Open Bites : main skeletal etiologies PFH/AFH > 65% PFH/AFH > 65% PFH/AFH > 65% PFH/AFH =62%-65% Normal maxillomandibular relation PFH /AFH < 62% PFH /AFH < 62% PFH /AFH < 62%
  93. 93. Aleppo , Citadel – SYRIA
  94. 94. Anterior Open Bite Treatment in the Deciduous and Mixed Dentitions Next : Part 2 …. Dr.Marwan Mouakeh, Consultant Orthodontist Academic Adviser, Al-Hokail Polyclinic – Khobar ( KSA)

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