The Nature of Orthodontic Problems and Malocclusion

Evolution of Orthodontics

Angel’s Molar Classification

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.

Malocclusion

• Any deviation from the ideal occlusal scheme

Epidemiology of Malocclusion• Ideal occlusion as defined by Angle is a rare

occurance• 65% of the US population present some type

of malocclusion

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.

What percentage of the population presents with severe crowding?

• About 15-20%

• Crowding increases with age• Is worst in the lower arch

Overjet

• Horizontal overlap of incisors

• Approx 2mm is considered normal

Malocclusion

What is the

prevalence of severe

overjet ?

(> 6mm)

Malocclusion

• 5 – 10%• Correlates with the prevalence of Class II

malocclusion

What is the prevalence of negative overjet?

Malocclusion

Malocclusion

• Less than 1% in the US

• Is a characteristic of Class III malocclusions

• Much more prevalent in Japan and China

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

Malocclusion

Deep bites are more prevalent in which ethnic

group?

A. BlackB. White

Malocclusion• Open bites are more prevalent in blacks• Deep bites are more prevalent in whites

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

How many patients in a typical US population have a posterior

crossbite?

About 10 % Is very similar between whites, blacks and

hispanics

Diastema

• A space between two adjacent teeth is called a diastema.

• Maxillary midline diastema is most commonly seen in mixed dentition phase

Malocclusion

• Which ethnic group has the higher prevalence of midline diastemas

A. WhiteB. BlackC. Hispanic

Malocclusion

• Blacks have double the prevalence of anterior diastema compared to whites

Assigned reading

Contemporary Orthodontics: Chapter 1 Pg 3-22

Bhoomika Ahuja Department of Orthoodnitcs

bahuja@umaryland.eduRoom 3213