W4 - Eruption Problems - Abdalla - do again Flashcards
Chronological age vs Biological age
Chronological age - number of years alive
Biological age - how old cells seem
*be specific when talking about which type of age in exams*
Which sex gets all the permanent teeth first? what age?
Girls - 12.5
Boys - 13
However there is a wide range of variance
What determines dental age? (4)
Which teeth have erupted?
Amount of resorption of primary teeth
Amount of development of permanent teeth
Demirjian & Nolla’s staging methods
Why is dental age important?
Determines the appropriate time for orthodontic intervention
What determines a “retained deciduous tooth”
tooth remains in place beyond its normal, chronological shedding time due to the absence or slowed development of the permanent successor
What determines an “over-retained deciduous tooth”
A tooth whose unerupted permanent successor exhibits a root development in excess of 75% of its exposed final length
4 Systemic factors affecting eruption (conditions)
- Cleidocranial dysplasia
- Ectodermal dysplasia
- Gardner syndrome
- Apert syndrome
Local factors affecting eruption (7)
- Barriers in the eruption pathway
- Abnormal position
- Tooth deformity
- Bone deficit
- Lack of space
- Dilaceration
- Ankylosis
What is Primary Failure of Eruption
Posterior teeth fail to erupt despite clear eruption pathway
- Unknown etiology
- Unresponsive to ortho force
Treatment of Primary Failure of Eruption (5 step)
- Wait until completion of veritcal growth
- Segmental osteotomy
- Distraction osteogenesis
- Bone grafting
- Implant
What happens with ankylosis? Cause?
Fusion of cementum or dentine with alveolar bone
- Affected tooth remains in place while adjacent teeth continue to erupt
- Changes in PDL
- Unknown cause
Most common tooth to be Ankylosed
Deciduous second molars
Defintition of tooth impaction
Failure of a tooth which exhibits more than ¾ of final root length to erupt into a normal function position
Treatment of impaction is based on ______ (4)
Treatment is based on:
- Cause of the impaction
- Position of tooth
- Ability to move tooth (ortho)
- Likelihood of causing damage to adjacent teeth
2 common orthodontic indications for third molar removal are
- Distalisation of lower molars
- Preparation for jaw surgery (BSSO split location is at third molar site)
*crowding is NOT a reason* - no sound evidence that states wizzies cause incisor crowding
What is an ectopic tooth?
Most common tooth?
- Tooth is following an abnormal eruption path
- Only becomes impacted if it cannot erupt
Maxillary first molars are most common
Aetiology of ectopic eruption of first molars (6)
- Larger than normal 6’s
- Small maxilla
- Class 3
- More pronounced angle of eruption
- Genetics
- Association with other dental anomalies (impacted canines)
How are ectopic eruption of first molars most often diagnosed?
- Incidental bitewings
- Tipping of 2nd deciduous molars
- Infra-occlusion of first permanent molar
What is the problem with ectopic eruption of first molars? (3)
- Loss of space
- Impaction of second premoalrs
- Over eruption of lower first molar
Management of ectopic eruption of first molars
Spontaneous resolution is unlikely after age 7
- Brass wire
- Elastomeric separator
- Fixed appliances
- Extractraction of deciduous molar
How are impacted incisors diagnosed
By deviation of eruption sequence
- Eruption of contralateral tooth occured more than 6 months ago
- Both central incisors remain unerupted 12 months after lower centrals
Aetiology of impacted incisors (4)
- Supernumaries
- Dilaceration
- Early loss of primaries
- Retained primaries
Managment of impacted incisors
Children <9 y.o. (incomplete root dvlpmt of perm incisor)
- Remove obstruction
- Create space if needed
- Monitor eruption for 18 months
Children >10 y.o.
- remove obstruction, expose and bond bracket
- OR
- Extract and transplant/implant
What is the most commonly impacted tooth after wizzies + why?
Maxillary canines
- Longest period of development
- Greatest distance to travel from point of formation to mouth
Aetiology of ectopic maxillary canines (3)
- Prolonged retention of primary canine
- Association with small/absent lateral incisor
- Genetic
though not completely clear
Why must the buccal mucosa be palpated in pts 9-10?
To feel canine bulge
- If canine cannot be palpated, radiograph is indicated
Biggest complication of impacted maxillary canines
Resorption of incisors
Describe the probability of impacted canines erupting
Divide the OPG into zones
- whole premolar or deciduous canine
- Distal lateral
- mesial lateral
- Distal central
- mesial central
Highest chance of successful eruption is canine is positioned in the distal lateral section
How is canine impaction treated (2)
- No tx / extraction
- Surgical exposure and alignment (chain - long tx time)
After what age is root resorption unlikely in untreated canine impaction
Age 14
Ectopic eruption of first molar
Common causes of tooth impaction
- Failure of resorption of deciduous teeth
- Abnormal eruptive pathway
- Supernumaries
- Crowding
- Dentigerous cysts
- Ankylosis
Impaction treatment options (3)
- Extraction
- Make space +/- surgical exposure
- Make space and transplant tooth
Ectopic eruption of first molars
Impacted incisors
