June 21, 2023

Impacted teeth, it’s in the timing

6 minutes

Join me for a summary looking at impacted teeth and key components of timing which affect not only the success of alignment, but also root formation. This podcast also explores the occurrence of asymmetries of both dental and facial due to impacted teeth, and what can be done about it. This podcast is a summary of the AAO lecture by Stella Chaushu and Adrian Becker.

Timing

Role of timing to the impacted tooth, the adjacent teeth and alveolar and skeletal growth.

Implications of timing on impacted teeth:

Eruptive potential

Root development

1/ Eruptive potential and timing

Interceptive treatment Ideal time for spontaneous eruption is ½ to 2/3 of final root length.

Orthodontic traction: Ideal time for active (orthodontic traction) eruption is 2/3 to ¾ final root length.

Principle:

Peak of eruptive potential is at 2/3 to ¾ of final root length

Root completed within 2.5 to 3 yrs post eruption

Timing of impacted maxillary canine interceptive treatment

Dental age of 9-10 years

Interceptive treatment includes: extraction C, D, distalisation molars, RME

Prognosis of treatment of impacted canines is uncertain and reduces with age.

Ideal early adolescence

Timing of impacted maxillary incisor interceptive treatment

Before age of eruption 7-8 years

Likely spontaneous eruption, but risk of damage to permanent incisor in surgery

After age of eruption > 8 years

Spontaneous eruption not predictable, likely require active (orthodontic traction)

Interceptive treatment

Removal of obstruction, spontaneous eruption 36-75%

Removal of obstruction + space creation spontaneous eruption 82-89%

(Sun et al AJODO 2006)

Root development

Impacted incisor due to obstruction – ideal time =7-8 yrs

Dilacerated upper incisors – ideal time – at ½ root or less = 6-7 yrs, as removal of root proximity to the anatomical barrier can reduce the dilaceration of the forming root

Timing of impacted premolar interceptive treatment

What to do when premolar root formation has not occurred in adolescent patient

If apex is open = root formation occurring

Timing of obstruction management

Removal: As early as possible

Orthodontic traction: Delay until bony infil, otherwise loss of gingivla and alveolar supoort

2/ Root development

Canine root development

Hooked apex 3-4 times more likely with impacted canines

Shorter root

impacted incisor 2.3mm shorter root Sun 2016, Impacted canine 2.3mm shorter roo Cao 2021

Total volume unaffected (length + hook)

Prevalence and severity of dilaceration increase with age until apex closed

Dilacerated root respond to traction/

Yes but increased treatment difficulty and duration , example of 2 years

Arrested root development

Can arrested root development be reversed?

If root abuts with an anatomical barrier. Such as nasal floor, it is the cause of the arrested development

Orthodontic traction and movement away from the barrier = continued root development

Early exposure and orthodontic traction

Implication of impacted tooth and asymmetry

Impacted tooth can affect alveolar and skeletal growth

Cases with asymmetry significantly higher in impacted group.

Asymmetry index 27% Vs 3.4%

Chin asymmetry 52% Vs 14%

Occlusal cant 38% Vs 10%

Timing of treatment, if delayed = occlusal cant increased with age.

After treatment, asymmetry can persist = treat as early as possible to limit asymmetry (managing impaction will not correct asymmetry)

...more

View all episodes

By Farooq Ahmed

77 ratings

June 21, 2023

Impacted teeth, it’s in the timing

6 minutes

Timing

Role of timing to the impacted tooth, the adjacent teeth and alveolar and skeletal growth.

Implications of timing on impacted teeth:

Eruptive potential

Root development

1/ Eruptive potential and timing

Interceptive treatment Ideal time for spontaneous eruption is ½ to 2/3 of final root length.

Orthodontic traction: Ideal time for active (orthodontic traction) eruption is 2/3 to ¾ final root length.

Principle:

Peak of eruptive potential is at 2/3 to ¾ of final root length

Root completed within 2.5 to 3 yrs post eruption

Timing of impacted maxillary canine interceptive treatment

Dental age of 9-10 years

Interceptive treatment includes: extraction C, D, distalisation molars, RME

Prognosis of treatment of impacted canines is uncertain and reduces with age.

Ideal early adolescence

Timing of impacted maxillary incisor interceptive treatment

Before age of eruption 7-8 years

Likely spontaneous eruption, but risk of damage to permanent incisor in surgery

After age of eruption > 8 years

Spontaneous eruption not predictable, likely require active (orthodontic traction)

Interceptive treatment

Removal of obstruction, spontaneous eruption 36-75%

Removal of obstruction + space creation spontaneous eruption 82-89%

(Sun et al AJODO 2006)

Root development

Impacted incisor due to obstruction – ideal time =7-8 yrs

Dilacerated upper incisors – ideal time – at ½ root or less = 6-7 yrs, as removal of root proximity to the anatomical barrier can reduce the dilaceration of the forming root

Timing of impacted premolar interceptive treatment

What to do when premolar root formation has not occurred in adolescent patient

If apex is open = root formation occurring

Timing of obstruction management

Removal: As early as possible

Orthodontic traction: Delay until bony infil, otherwise loss of gingivla and alveolar supoort

2/ Root development

Canine root development

Hooked apex 3-4 times more likely with impacted canines

Shorter root

impacted incisor 2.3mm shorter root Sun 2016, Impacted canine 2.3mm shorter roo Cao 2021

Total volume unaffected (length + hook)