Anterior Open Bite and Deep Bite

Copyright (c) By Dr. Hla Hla Yee
Department of Orthodontics
University of Dental Medicine, Yangon

1. Anterior Open Bite Dr.Hla Hla Yee

2. Definition The absence of any vertical incisor overlap between the upper and lower incisors.

3. Causes ( 1 ) Skeletal causes   Excessive vertical growth of maxilla often more posteriorly than anteriorly and posterior growth rotation of the mandible.  

4. Clinical Features (Skeletal open bite)   Increased lower facial height Increased maxillary-mandibular plane angle Increased Frankfort-mandibular plane angle Obtuse gonial angle Upward slope of the maxillary plane Steep mandibular plane Short mandibular ramus  

5. ( 2 ) Dental causes Excessive eruption of posterior teeth Incisors eruption is impeded

6. ( 3 ) Soft tissue Decrease in tonic muscle activity that occur in muscle dystrophy , cerebral palsy muscle weakness syndrome. Therefore , the mandible drops downward from the rest of the facial skeleton. Therefore , excessive eruption of posterior teeth and narrowing of the maxillary arch and anterior open bite.

7. Muscle weakness syndromes

8. ( 4 ) Habit tongue thrust Thumb sucking Mouth breathing  

9. ( 5 ) Others Localized failure of maxillary dento-alveolar development resulting in an open bite is seen in clefts lip and palate. Hemimandibular hypertrophy – excessive growth of mandible, the dental occlusion shows open bite on the effected site.    

10. Hemimandibular hypertrophy

11. ( 6 ) Combination

12. Treatment

13.   For skeletal open bite In mild case , Can align arches and accept ( or ) try to restrain vertical development of maxilla and / or upper molars with headgear ( or ) functional appliance with posterior bite blocks. Extrusion of incisors is unstable.

14. Anterior vertical elastics

15. In more severe case - surgery or combined treatment.

16. For dental open bite Intrusion of posterior teeth or extrusion of the labial segment by using ( 1 ) High pull headgear to the upper molars is the best approach if excessive vertical development of the posterior maxilla. This treatment will have to be continued until growth is nearly complete, usually well into a retention period. The headgear to the maxillary molars directing the face upward as well as posteriorly. The effect of this, in patients who are still actively growing, is simply to inhibit the eruption of posterior teeth, allowing the anterior segment to catch up.

17. ( 2 ) Inter occlusal bite blocks is controlled the eruption of lower teeth. ( 3 ) bite blocks incorporating repelling magnets to facilitate posterior tooth intrusion.  

18. ( 3 ) Fixed appliances - vertical intermaxillary elastics. ( 4 ) Open bite associated with increased labioversion of the incisors ( Bimaxillary ) - Closure of openbite by retraction of proclined incisors.

19. Vertical intermaxillary elastic

20. Closure of openbite by retraction of proclined incisors.

21. Deep Bite ( Increased Overbite ) Excessive overlap of the anterior teeth Dr.Hla Hla yee

22. Right buccal occlusion Left buccal occlusion

23. Facial profile

24. Causes (1 ) Skeletal cause – ( short face ) due to increased posterior facial height (long mandibular ramus , mandible rotates upward and forward direction). Clinical Features Reduced lower facial height Short nose – chin distance Low mandibular plane angle Flat mandibular plane Low maxillary – mandibular plane angle Acute gonial angle

25. ( 2 ) Dental cause – due to a. Supraeruption of lower incisors and infraeruption of the molars. Therefore, Curve of Spee is exaggerated. b. Retroclined incisors Increased interincisal angle ( Average 130 degree ) Range 125-135 degree Above this value the tendency for the lower incisors to erupt may be inadequately resisted.

26. ( 3 ) Soft tissue Due to high lip line. Therefore the upper incisors are retroclined.

27. Treatment For skeletal deep bite Correction of skeletal deep bite problems requires rotating the mandible downward. Thereby increasing the mandibular plane angle and anterior face height.

28. ( 2 ) For dental cause ( 1 ) Extrusion ( eruption of molars ) Passive eruption of lower molars An anterior bite plane is incorporated into a removable appliance so that the mandibular incisors occlude with the plastic plane lingual to the maxillary incisors. This approach prevents the posterior teeth from occlusion and encourages their eruption. Active extrusion of molars – in either arch is possible by using a fixed – appliance.

29. ( 2 ) Intrusion of incisors ( a ) Absolute intrusion Absolute intrusion of the upper and lower incisors moving their root apices closer to the nose and lower border of the mandible respectively. In the absence of growth, the absolute intrusion and extrusion are possible. ( b ) Relative intrusion Achieved by preventing eruption of incisors while growth provide vertical space into which the posterior teeth erupt.

30. Absolute intrusion

31. Extrusion Relative intrusion ( growth required )

32. Utiity arch

33. ( 3 ) Proclination of upper incisors and proclination of lower incisors.