This document provides an overview of transverse malocclusions, specifically crossbites and scissor bites. It defines and classifies different types of transverse malocclusions such as anterior and posterior crossbites. It discusses the prevalence, etiology, clinical features, diagnosis and various treatment options for correcting transverse malocclusions depending on the specific case. Treatment may involve the use of removable or fixed appliances, selective grinding, dental expansion techniques, and in some cases, surgical intervention. Long term retention is emphasized after correcting the underlying skeletal discrepancy.

1. ‫الرحيم‬‫الرحمن‬‫هللا‬‫بسم‬
Sudan International University
Faculty of Dentistry
Department of Orthodontics
Transverse malocclusion
Mohanad Elsherif
BDS (U of K), MFD RCSI, MFDS RCPS(Glasg), MSc (Orthodontics), M.Orth. RCSEd

2. Objectives
 Definition
 Classification
 Prevalence
 Etiology
 Clinical features
 Diagnosis
 Treatment

3. malocclusion
Crossbite Scissor bite

4. Transverse
malocclusion
1. Cross bite:
It is the malocclusion where the lower teeth overlap the upper teeth in
the horizontal (transverse) plane.

6. a. Anterior crossbite
it is either:
I. Single tooth: involve only one tooth.

7. a. Anterior crossbite
II. Segmental (also called reversed overjet).

8. 2. posterior crossbite
I. unilateral: involve only one side.

9. 2. Posterior crossbite
II. bilateral: involve both sides.

10. Transverse
malocclusion
2. Scissor bite (also called lingual crossbite):
It is the malocclusion where the lower posterior teeth completely occlude lingual
to the upper posterior teeth.

11. Anterior crossbite
 affect around 3% of US population.
 Can affect one or more anterior teeth
 The more the teeth in crossbite, the greater the chance of
skeletal discrepancy.

12. Anterior crossbite
 Possible causes are:
 Lack of space
 Platally displaced upper incisor due to
retained deciduous tooth, supernumerary
tooth, trauma or pathology)
 Anterior displacement of the mandible.
 Skeletal problem.

13. Consequence of cross bite
 TMJ problem, specially if
associated with displacement
 Periodontal breakdown
(e.g. to lower incisor).
 Esthetic concern (in case of
anterior crossbite)

14. Treatment
 The success of correction depend on
 Adequate space within the arch.
 Adequate overbite.

15. Treatment options
 Single tooth crossbite:
 Tongue blade
 Removable appliance with Z spring
 Inclined bite plate
 Fixed appliance

16. 1. Tongue blade

17. 2. Removable appliance with Z spring

18. ACTIVE COMPONENT: Z-spring to 1/

19. ACTIVATE THE Z-SPRING....

21. ...VOILA!

22. Treatment options
 Removable appliance with Z spring

23. Treatment options
 Fixed appliance

24. Treatment options
 Segmental crossbite
 Removable appliance
 Fixed appliance
 Facemask
 Functional appliance

25. 1. Removable appliances

26. PROBLEM 2: All four incisors inside bite, with
deep reverse overbite

27. RETENTION: Adams cribs 6/6 and 4/4

28. ANTERIOR RETENTION: Fitted labial bow 21/12

29. ACTIVE COMPONENT: Expansion screw to
section 21/12

30. BITE OPENING: occlusal capping posteriorly

31. Screw is opened by one quarter turn twice a week
and pushes upper incisors forward over the bite

34. URA being used to procline 1/1 using a screw section

35. Facemask

36. Functional appliances

37. Fixed appliances

38. Posterior crossbite
 Can be unilateral or
bilateral
 Can affect one or more
buccal segment teeth
 Often associated with
mandibular displacement

39. Incidence of posterior crossbite
 Affect 8-16 % of the population
Foster & Hamilton 1969
 No differance between gender and races
 80% assosciated with mandibular
displacement

40. Posterior crossbite
 Posterior crossbites have six possible
explanations:
(1) The upper arch is too narrow
(2) the lower arch is too wide
(3) a lateral functional shift occurs during closure of the
mandible
(4) one or more teeth are displaced toward the palate in the
maxillary alveolar ridge
(5) one or more teeth are displaced toward the buccal side of
the mandibular alveolar ridge
(6) combinations of the above explanations.

41. Etiology
 Skeletal factors
 Soft tissue factors
 Dental factors
 Habits
 Others

42. Etiology
 Skeletal factors:
 Due purely to a mismatch in the relative widths of the
arches (i.e. small maxilla, wide mandible or both).
 Due to an anterior-posterior discrepancy resulting in
relative cross bite.
 True skeletal asymmetry (hemimandibular
elongation, …….).

43. Etiology
 Dental factors:
 Palatally displaced upper buccal segment teeth
and/or lingually displaced lower buccal segment teeth.
 High cusp canine or occlusal interference that result
in mandibular displacement
 Improper restoration (e.g. overfilled restoration or
improper crwon design) that result in displacement.

44. Etiology
 Soft tissue factors:
 Microglossia (small tonuge size)
 Enlarged adenoid that result in low tongue position.
 Improper restoration (e.g. overfilled restoration or
improper crwon design) that result in displacement.

45. Etiology
 Habits
 Thumb sucking habits
 Mouth breathing habits

46. Etiology
 Other causes
 Congenital causes: cleft lip and palate
 Trauma
 Pathology of the TMJ’s

47. Treatment options
 Treatment will depend on:
 The nature of the problem (skeletal or dental)
 The age of the patient
 How many teeth in cross bite.
 Whether displacement is present or not.

48. Treatment options
 Cross elastics.
 Selective grinding to remove occlusal prematurity
 Dental expansion using removable plates or a
quad helix
 Skeletal expansion appliances
 Surgically assisted palatal expansion

49. 1. Single tooth posterior
crossbite
 Cross elastics

50. 2. Crossbite with occlusal
prematurity
 Selective grinding to remove occlusal prematurity

51. 3. Dental crossbite
 Management of dental crossbite
 Dental expansion using:
 Removable expansion screw (plates)
 Fixed expanders (W arch, quad helix,…)

52. Removable expansion screw

53. Problem 5: unilateral or bilateral crossbite with
displacement on closure – note narrow upper
arch

54. Retention: Adams cribs on 6 4 / 4 6
Midline Glenross screw for expansion

55. Screw is turned one quarter turn every 3 days
(Mondays and Thursdays) – usually there are
about 36 turns of the screw

58. Quad helix
Coffin spring
W arch
Fixed
expanders

59. 4. Dental crossbite
 Management of dental crossbite
 In adolescence ( age 15 and younger) 
Skeletal expansion.
 In adults  Surgically assisted palatal expansion.

60. Skeletal (rapid) maxillary
expansion

61. Surgically
assisted palatal
expansion

62. After skeletal expansion
 Following skeletal
expansion the appliance is
stabilized with for 3
months, before advancing
to the next phase of
treatment.

63. Retention
 Long term retention is
required using rigid acrylic
retention appliance

64. Declaration
 The author wish to declare that; these presentations are his original work, all
materials and pictures collection, typing and slide design has been done by the
author.
 Most of these materials has been done for undergraduate students, although
postgraduate students may find some useful basic and advanced information.
 The universities title at the front page indicate where the lecture was first
presented. The author was working as a lecturer of orthodontics at Ibn Sina
University, Sudan International University, and as a Master student in Orthodontics at
University of Khartoum.
 The author declare that all materials and photos in these presentations has been
collected from different textbooks, papers and online websites. These pictures are
presented here for education and demonstration purposes only. The author are not
attempting to plagiarize or reproduced unauthorized material, and the intellectual
properties of these photos belong to their original authors.

65. Declaration
 As the authors reviews several textbooks, papers and other references during
preparation of these materials, it was impossible to cite every textbook and journal
article, the main textbooks that has been reviewed during preparation of these
presentations were:
Contemporary Orthodontics 5th edition; Proffit, William R, Henry W. Fields, and
David M. Sarver.
Handbook of Orthodontics. 1st edition; Cobourne, Martyn T, and Andrew T. DiBiase.
Essentials of orthodontics: Diagnosis and Treatment; Robert N. Staley, Neil T. Reske
Orthodontics: Current Principles & Techniques 5th edition; Graber, Lee W, Robert L.
Vanarsdall, and Katherine W. L. Vig
Orthodontics: The Art and Science. 3rd Edition. Bhalajhi, S.I.

66. Declaration
 For the purposes of dissemination and sharing of knowledge, these
lectures were given to several colleagues and students. It were also
uploaded to SlideShare website by the author. Colleagues and students
may download, use, and modify these materials as they see fit for non-
profit purposes. The author retain the copyright of the original work.
 The author wish to thank his family, teachers, colleagues and students
for their love and support throughout his career. I also wish to express
my sincere gratitude to all orthodontic pillars for their tremendous
contribution to our specialty.
 Finally, the author welcome any advices and enquires through his
email address: Mohanad-07@hotmail.com

67. Thank You