1. Aetiology and extractions Flashcards
Describe the main aetiological factors in malocclusions
- GENERAL FACTORS
- SKELETAL RELATIONSHIP
- TOOTH SIZE / ARCH SIZE DISPROPORTION
- soft tissues
- genetic and developmental disorders
- TMJ trauma / growth abnormalities
- LOCAL FACTORS (more important to us as they are the ones we can identify and prevent/ treat in children/adolescents)
- EARLY LOSS / PROLONGED RETENTION OF DECIDUOUS TEETH
- ECTOPIC TEETH
- Absent teeth, supernumeraries
- Impaction, delayed eruption
- Fraenum, local pathology
- Dental trauma
Describe the main local factors and anomalies that may present in the developing dentition
- Deciduous Teeth
– Early loss or prolonged retention of deciduous teeth - Permanent: number of teeth
–Absent teeth
–supernumeraries
–early loss (6s, 1s) - Permanent: position of teeth
–ectopic canines
–impaction of 1st molars, or premolars - Fraenum
what are the effects of early loss of upper E
impacted and crowded lower premolar
(E extracted due to caries)
6 drifting mesially and not leaving enough space for the 4 and 5 ie posterior crowding
Fitted in patient who has lost both lower Es-
(to prevent the 6 drifting forwards
Space maintainers ie lingual arch (fixed)
Early Loss of Deciduous Teeth
Effects depend on:
- Tooth lost
- Age
- Degree of Crowding in the Arch
Effects of early loss of deciduous teeth- tooth loss
–D, E space loss as 1st permanent molars drift mesially
(causes premolar crowding)
–C incisor midline shift as permanent incisors drift into
space
–A, B minimal effect
Effects of early loss of deciduous teeth- age
–Effects more severe with earlier loss
Effects of early loss of deciduous teeth- degree of crowding in the arch
–more space loss with D or E loss if crowding present
– greater midline shift with C loss if perm incisors crowded
Prolonged Retention of Deciduous
Teeth
(how common, which teeth and effects? what happens?)
- Relatively common
- Usually Es or Ds (radiograph re. successor)
- May delay permanent successor
- May become “submerged” or “infraoccluded” due to ankylosis
–tipping of adjacent teeth (first molars)
–almost all exfoliate naturally
–extract only if becoming completely submerged
Developmental Absence of
Permanent Teeth (“Hypodontia”)
how common and what other type of lack of teeth canyou have?
Relatively common (2-3%)
* Anodontia (complete absence)
what are the most common teeth missing? and what is severe hypodontia?
excluding 3rd molars:
upper laterals, then 2nd premolars, and lower central incisors
6 or more missing teeth (excluding 8s)
Tx of hypodontia?
- space closure
- Open or maintain space then bridgework / implants / denture
- accept (e.g. lower 5s)
Hypodontia: Upper Laterals
. how common
. associated with?
. Tx?
- Common (2-3%)
- Associated with ectopic canines and small
contralateral lateral incisors
*–space closure (crowding, Class II cases, 3s acceptable)
–bridgework (no crowding, 3s poor colour)
–usually need fixed appliances
Absent Second Premolars
- how common?
- can appear on Rx as late as?
- Tx?
- Prognosis?
- Common (2%)
- Can appear on radiographs as late as age 8 years
- – space closure (extract deciduous early)
– bridgework
– use space to treat crowding
– accept and retain Es
0 uncertain, unusual to last beyond age 30
Absent Lower Central Incisors- features?
treatment?
- Rare
- A`s usually retained
- Close space or bridgework
Supernumerary Teeth ($)
incidence? and location?
- Incidence 1-2%
- 80% are in the anterior maxilla
(* OPG - anterior occlusal)
Supernumary teeth classification?
- Morphology (Coniform and Tuberculate)
- Position (Mesiodens, Supplemental, Paramolar)
Supernumary teeth clinical effects?
- delayed eruption of teeth (e.g. Upper centrals)
- may erupt (mesiodens), crowding
- midline diastema (mesiodens)
Supernumerary Teeth: Treatment
- No treatment
- Extract
- Exposure and alignment of teeth with delayed eruption (Upper incisors)
- However, more than 70% of unerupted upper central incisors will erupt following removal of a supernumerary tooth
Impacted teeth
- First permanent molars
- Premolars
- Third molars
Impacted Teeth: Perm First Molars
incidence
location
prognosis?
3-4 percent
almost always in maxilla
2/3 will correct spontaneously, although unlikely to improve after 8 years
treatment of impacted permenant first molars?
- extraction of E
- Simple URA to disimpact
Impacted Teeth: Premolars
- what tooth and why
Usually 2nd premolars
Early loss of E
Tx of impacted premolars
- Extract 4 to allow eruption of 5
- Extract 7 and distalise 6 to create space
- Extract 5 (surgical)
- No treatment and review regularly
Ectopic Maxillary Canines
incidence?
2 percent
see separate lecture
Local Factors: Labial Fraenum-
what is it and sometimes associated with?
Abnormally thick upper labial fraenum
* midline diastema
Treatment of labial fraenum?
- wait until upper canines erupted before
treating - fraenectomy during or after space closure
Early loss of Permanent Teeth- with which?
- 1st molars (caries)
- Upper incisors (trauma)
Early loss of Permanent 1st Molars
* Why is it a problem?
- Residual space
- overeruption of opposing first molar
- space is difficult to use with appliances for treating anterior crowding or overjet
ideal age for spontaneous closure of 6s?
8-9
features of early loss of 6s?
upper spaces close better than lower
unopposed 6s overerupt
what is minimal with early loss of 6s?
midline shift with unilateral loss of a 6
management of carious 1st molars is done how?
extraction best at age 8-9
risk of later extraction?
tipping
consideration for extraction of carious 6s
extraction of both upper and lower
lower 3rd molars?
very weak associated with lower incisor crowding
later lower incisor crowding alone is not an indication for lower 3rd molar extraction
urgical removal of impacted third molars should be limited to patients with
evidence of pathology
Early Loss of Permanent Upper
Incisors is due to … and is seen in
trauma
class II Div 1
early loss of permenant upper incisors is associated with
poor lower lip coverage
treatment of early loss of permenant upper incisors?
try to save if at all possible, (RCT, re-implant)
what are the options if lost or unsavable permanant upper incisors?
- Maintain space with prosthesis
- Close space orthodontically and crown lateral poor gingival margin & canine colour
abnormal tooth form?
- Dilaceration of permanent upper incisors
- Peg shaped upper lateral incisors
- strong association with ectopic canines
- other lateral may be absent
what is dilaceration of upper lateral incisor, due to what
- root bent
- trauma to deciduous predecessor, age 4-5
prognosis of dilacerated upper lateral
- delayed or non-eruption
- orthodontic alignment sometimes possible
peg shaped upper laterals have a strong association with … and the … may be absent
ectopic canines
other lateral
most malocclusions are the result of complex and poorly understood interaction of
genetic and environmental factors
… and … are superimposd on the genetic background
habits and local factors
simple measures can solve and treat successfully
local factors and habits
more complex treatment may be needed for
skeletal problems and tooth-arch size disproportions (crowding and spacing)
