Skeletal problems in the mixed dentition

Question 0

As a general rule, the most effective time for undertaking the correction of a class II malocclusion is during the adolecent growth spurt as this will optimise mandibular growth whilst limiting overall treatment time. However, several exceptions exists which indicate early intervention. What are these?

Answer 0

1) Class II females with a significant skeletal disrepency
2) An increased overjet, which is a source of bullying and teasing
3) Increased overjet, which is at risk of trauma (e.g. gross lip incompetence and marked maxillary protrusion)

Question 1

If correction of a skeletal class II malocclusion is elected for during the mixed dentition stage, how can this be carried out?

Answer 1

1) Removable appliance:
- If the upper labial segment is proclined and spaced, an URA with an active labial bow. In the presence of maxillary excess or a class II buccal segment relationship, headgear may also be used in conjuction with the URA.
2) Functional Appliances
- As there may be problems associated with retention of tooth-borne appliances in the mixed dentition as 6s are not fully eruprted, a myoddynamic appliance can overcome this.

Question 2

An anterior crossbite in the mixed dentition is often a sign of an underlying class III skeletal relationship and will tend to worsen with age. Treatment decisions are often delayed to monitor further growth and better determine extent of skeletal problem. When would early treatment be considered appropriate?

Answer 2

1) Skeletal class I or mildly class III
2) Average or reduced lower face height
3) Large anterior displacement on closing

Question 3

If correction of a class III malocclusion is elected for during the mixed dentition, how can this be carried out?

Answer 3

1) Functional appliannces
- for milder class IIIs only. Results in upper incisor proclination, lower incisor retroclincation, backward and downward rotation of the mandible
- a reverse twin block can be used
2) Fixed appliances
- 2 x 4 appliance
3) Protraction headgear
- elastics from either a removable or fixed appliance to a facemask resting on chin and forehead resulting in an anterior skeletal displacement of the maxilla. However, long term stabilty unpredcitable.