1. The Nature of Orthodontic Problems and Malocclusion

2. Evolution of Orthodontics

3. Angel’s Molar Classification

4. The focus of modern orthodontic treatment is on improving not only dental and skeletal but also soft tissue aspects of orthodontic problems, in combination with other dental treatment as needed.

5. Malocclusion
Any deviation from the ideal occlusal scheme

6. Epidemiology of Malocclusion
Ideal occlusion as defined by Angle is a rare occurance
65% of the US population present some type of malocclusion

7. Crowding
Space required by the dentition for all teeth to be aligned normally exceeds the space available in the dental arch.
Rotations, incisor irregularity etc.

8. What percentage of the population presents with severe crowding?

9. About 15-20%
Crowding increases with age
Is worst in the lower arch

10. Overjet
Horizontal overlap of incisors
Approx 2mm is considered normal

11. Malocclusion
What is the prevalence of severe overjet ?
(> 6mm)

12. Malocclusion
5 – 10%
Correlates with the prevalence of Class II malocclusion

13. What is the prevalence of negative overjet?
Malocclusion
What is the prevalence of negative overjet?

14. Malocclusion Less than 1% in the US
Is a characteristic of Class III malocclusions
Much more prevalent in Japan and China

15. Overbite Overbite is the vertical overlap of incisors.
1-2mm overbite is considered normal.
Excessive overbite is called deep bite
>5mm overbite is considered severed deep bite
Overbite <0mm is called an open bite

16. Malocclusion Deep bites are more prevalent in which ethnic group?
Black
White

17. Malocclusion Open bites are more prevalent in blacks
Deep bites are more prevalent in whites

18. Posterior Crossbite
Maxillary posterior teeth are lingually positioned to mandibular posterior teeth.
Discrepancy in the widths of maxillary and mandibular arches.
Can arise from dental causes as well

19. How many patients in a typical US population have a posterior crossbite?

20. Is very similar between whites, blacks and hispanics
About 10 %
Is very similar between whites, blacks and hispanics

21. Diastema A space between two adjacent teeth is called a diastema.
Maxillary midline diastema is most commonly seen in mixed dentition phase

22. Malocclusion
Which ethnic group has the higher prevalence of midline diastemas
White
Black
Hispanic

23. Malocclusion
Blacks have double the prevalence of anterior diastema compared to whites

24. Department of Orthoodnitcs
Assigned reading
Contemporary Orthodontics: Chapter 1 Pg 3-22
Bhoomika Ahuja
Department of Orthoodnitcs
Room 3213