This document provides an introduction to orthodontics. It begins by defining orthodontics as the branch of dentistry concerned with preventing, intercepting, and correcting malocclusions and other dentofacial deformities. Ideal occlusion and Andrews' six keys of occlusion are described. The document outlines the different branches of orthodontics including preventive, interceptive, and corrective orthodontics. The aims of orthodontic treatment are discussed as achieving aesthetic harmony, functional efficiency, and structural balance. Finally, the 4th year orthodontic syllabus is summarized.

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

2. Perio
Prosthesis
Ortho

3. Introduction to orthodontics?
What is Orthodontics?

4. Definition
 It is the branch of dentistry that concern with
prevention, interception and correction of
malocclusion and other dento-facial deformities.

5. Definition
 It is the branch of dentistry that concern with
prevention, interception and correction of
malocclusion and other dento-facial deformities.

6. Ideal occlusion
 Anatomically perfect alignment of teeth.
 How do we know it?
Andrews Six Key’s of
Occlusion

7. Andrews six keys of occlusion
Key (1): Molar relationship:
1. The distal surface of the distal marginal ridge of the upper
first permanent molar contacts and occludes with the mesial
surface of the mesial marginal ridge of the lower second molar.
2. The mesiobuccal cusp of the upper first permanent molar falls
within the groove between the mesial and middle cusps of the
lower first permanent molar.
3. The mesiolingual cusp of the upper first molar seats in
the central fossa of the lower first molar.

8. Andrews six keys of occlusion
Key (2): Crown angulation (tip):
The gingival portion of the long axis of each crown is distal to
the incisor portion.

9. Andrews six keys of occlusion
Key (3): Crown inclination (torque):
a. Incisors: labial crown inclination is sufficient to prevent over
eruption of the anterior teeth and to allow proper position of
posterior contact.
b. Upper canines, premolars and molars: a palatal inclination
is present, slightly more pronounced in the molars.
c. Lower canines, premolars and molars: lingual inclination
is present which increases progressively from front to back.

10. Andrews six keys of occlusion
Key (4): Rotation:
Absent

11. Andrews six keys of occlusion
Key (5): Contact:
Tight contact should be present with no spacing between teeth.

12. Andrews six keys of occlusion
Key (6): Occlusal plane:
The curve of spee should be absent or minimal.

13. Definition
Ideal occlusion
Good (normal)
occlusion
Malocclusion
Mild
(acceptable)
deviation
Large
(unacceptable)
deviation

14. Malocclusion
It is an unacceptable deviation from ideal
occlusion that compromise the function
andor aesthetic.

15. Definition
 It is the branch of dentistry that concern with
prevention, interception and correction of
malocclusion and other dento-facial deformities.

16. Branches of orthodontics
Preventive
Orthodontics
Interceptive
Orthodontics
Corrective
Orthodontics

17. Preventive Orthodontics
Def: “These are the action taken to preserve the integrity
of what appears to be normal occlusion at specific time”.
 The preventive procedures are:
1. Caries control.
2. Parent counseling.
3. Space maintenance.

18. Contd Preventive Orthodontics
4. Monitoring of shedding of the teeth.
5. Correction of abnormal frenal attachment.
6. Treatment of locked permanent first molar.
7. Correction of abnormal oral musculature and related
habit.

19. interceptive Orthodontics
Def: “Early recognition and elimination potential
irregularities and developing malocclusion before it became
more sever”.
 The interceptive procedures are:
1. Space regaining.
2. Elimination of oral habits.

20. Contd interceptive Orthodontics
3. Correction of anterior and posterior crossbites.
4. Removal of hard or soft tissue or bony barrier that
prevent eruption of a tooth.
5. Resolution of crowding.
6. Serial extraction.

21. Corrective Orthodontics
Def: “These are procedures undertaken to correct a well-
established malocclusion”.
1. Non Surgical ( appliance).
2. Combined surgical and orthodontics.

22. Definition
 It is the branch of dentistry that concern with
prevention, interception and correction of
malocclusion and other dento-facial deformities.

23. Why do we do
ortho?

24. Aims of Orthodontics
Esthetic
Harmony

25. Aims of Orthodontics
Functional
efficiency

26. Aims of Orthodontics
Structur
al
Balance

27. Aims of Orthodontics
Aesthetic
harmony
Functional
efficiency
Structural balance
Jackso
n
trait

28. How can we achieve these
aims?

29. Scope of orthodontic
•Moving teeth1.
•Altering the soft tissue
envelop3.
•Producing skeletal changes2.

30. 4th year Syllabus
What we are going
to study this year?

31. Orthodontic syllabus
 Introduction to Orthodontics.

32. Orthodontic syllabus
 Classification of malocclusion.

33. Orthodontic syllabus
 Etiology of malocclusion.

34. Orthodontic syllabus
 Oral habits.

35. Orthodontic syllabus
 Growth and development.

36. Orthodontic syllabus
 Maturity indicators

37. Orthodontic syllabus
 Development of dentition and
occlusion.

38. Orthodontic syllabus
 Anchorage.

39. Orthodontic syllabus
 Removable appliances.
 Fixed appliances.

40. Orthodontic syllabus
 Functional appliances.
 Extraoral appliances.

41. Orthodontic syllabus
 Biomechanics and tooth movement.
Ultimate tensile strength
Yield strength
Proportional limit
Failure point
Stress
Strain

42. The Rule

43. That’s it

44. 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.

45. 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.

46. 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

47. Thank You