Interceptive Orthodontics Flashcards
What is the most common neo-natal tooth? How treat?
Lower incisors
Extract if risk of inhalation or is causing difficulty with breastfeeding
What are the three eruptive phases?
Pre-eruptive
Eruptive
Post-eruptive
What occurs in pre-eruptive phase?
Starts when crown starts to form, ends when crown formation is complete
Small mesial and distal movements occur and the crowns reposition themselves within the growing and developing jaw
What is the eruptive phase?
Starts when root begins to form, ends when teeth reach occlusal plane
Intra osseous stage is within bone, extra osseous is out of bone
Tooth germ moves into place as predecessor erupts / falls out
What is the post eruptive phase?
Tooth movement and eruption continues as root forms throughout life
This can be due t abrasion or attrition, mesial drifts tends to occur when tooth surface loss occurs
What’s occurs in the intra-osseous stage of eruption?
Root formation begins as proliferation of the epithelial root sheath begins and then dentine and pulp form
Tooth moves slowly incisally
Reduced enamel epithelium fuses with oral epithelium to form junctional epithelium
What’s occurs in the extra-osseous stage of eruption?
Crown penetrates through epithelial layers
Epithelium becomes lower on clinical crown until gingiva is formed
Continues eruption until contacts tooth on opposing arch
What causes eruption?
The dental follicle
- resorbs overlying bone
- facilitates connective tissue degradation and produces eruption pathway
- promote alveolar bone growth at base of tooth
- traction forces within the PDL via fibroblasts
- ectomesenchymal cells form root and cementum below
What is interceptive orthodontics
Any procedure that will reduce or eliminate the severity of developing malocclusion
Review eruption dates of permanent teeth
The permanent dentition erupts lingual to the primary dentition… where is the space gained for this to occur?
Lateral growth of the jaw increasing inter canine width
Upper incisors erupting more proclined rather than straight like primary teeth
Why might someone present like this?
Permanent canine germ is pressing on the root of the primary laterals
This tends to resolve itself later in development
<2.5mm diastema should close
What concerns present themselves in these cases?
Left
- central incisors not erupted, yet laterals have
- cause for concern
Right
- asymmetry, lateral and contralateral central erupted but one central not
- should erupt within 6 months but if not then there is an issue
Why might an upper central incisor not erupt?
Supernumerary teeth
Trauma to primary dentition can cause dilaceration of permanent tooth germ
How would you investigate a missing upper central?
Proper history including trauma
Extra and intra oral assessment including palpating labially and palatally
Is primary tooth still there? Is it discoloured?
Radiograph with anterior occlusal or periapical
How might one treat an unerupted central?
Extract supernumeraries
Maintain or make space for eruption
Monitor for 12 months if patient is <9 yrs old as they have immature root apex
If >9yrs old then expose tooth and use gold chain to apply orthodontic traction
What can early loss of deciduous teeth cause?
Crowding
Centreline shift
What is a balancing extraction? What is a compensating extraction?
Balancing
- removal of tooth opposite side of same arch to maintain position of centreline
Compensating
- removal of tooth from opposing quadrant to maintain occlusion and prevent over eruption
Which teeth might you balance?
Cs
Es you tend not to balance but consider space maintainer to prevent shift
D’s can balance under GA
What is a space maintainer?
Removable or fixed appliance used to maintain space of a lost tooth
What impacts the decision on whether top extract poor prognosis first molars?
Age of patient / stage of development
Degree of crowding
Malocclusion type
What are the general rules for extracting a 6
If extracting lower, compensate with the upper
Don’t balance the extraction if tooth is sound condition, well aligned or well spaced
If extracting upper, don’t extract lower
How does digit sucking cause displacement on biting / posterior UNILATERAL crossbite
Narrowing of maxilla resulting in biting cusp to cusp
Because biting cusp to cusp, mandible must, displace to achieve ICP
What is the ugly duckling stage?
11-12 years of age
Less than 2mm diastema between upper centrals
Mesial eruption of maxillary canines should close this space
What is the leeway space?
Upper arch
- (primary canine + fm + SM) - (permanent canine + first premolar + second premolar) - 1-1.5mm
Lower arch
- (primary canine + fm + sm) - (permanent canine + first pm + second pm) = 2-2.5mm
What % of children 6 and 12 have diastema
What diastema should close?
6 - 96%
12 - 7% - with 3s erupted
<2.5mm should close
How manage ectopic eruption of the first permanent molar?
- If pt <7 years, monitor 6 months - 90% self correct
- Orthodontic separator
- Attempt to distal use FPM
- Extract the E
- Distal disking of the E
When should i assess first molars???
8-9 years of age!
any doubts re long term prognosis?
- refer for advice
What space maintainers can i use?
Removeable
- passive URA
- clasps on 6’s, Southend clasp, baseplate extended around teeth to prevent unwanted mesial drift, with mesial stop on individual teeth if required
Fixed
- band and loop
Most ideal result gained when FPM extracted when?
7 bifurcation calcifying
8s present
Class 1 / reduced overbite
Moderate lower crowding
Mild / moderate upper crowding
How can interceptive tx be used on posterior unilateral crossbites?
Displacement on closure and IOTN?? - YES treat!
- URA hyrax screw, or coffin spring
- baseplate with posterior bite plane to disclude teeth
How manage anterior crossbites???
Displacement, gingival recession, toothwear, mobility
- posterior bite plane
- Z spring
- Adam’s clasps
When should habits be stopped before?
9!
What instructions give to someone wearing an appliance?
Wear full time
Clean it twice per day minimum and after eating
Use fluoride mouthwash daily with no alcohol
Avoid sugar, sticky and hard foods
Remove for sports
Speech affected at first ad extra salvia but it will pass
Teeth moving and when eating might be painful
