orthodontic appliances Flashcards
what are removable appliances?
-appliances that are not attached to the teeth-they can be removed for cleaning/sports
what are the components of removable appliances?
BARA
-baseplate
-active component
-retentive component
-anchorage
what active components are in removable appliances?
SSB
-springs
-screws
-bows
what is the force applied by springs dependent on?
-length of wire
-radius of wire
-elastic stiffness of wire
give examples of retentive components…
CLASPS
-Adam clasps
-delta clasps
-ball-ended clasps
-southend clasps
what is the base plate made of?
acrylic
what is the function of the base plate?
-holds all components together
-provides anchorage of the appliance
define anchorage
anchorage is the resistance to unwanted tooth movements
newtons 3rd law
how do you increase the anchorage?
-use more clasps
-move only 1 or 2 teeth at a time
-use lighter forces
what are the advantages of removable appliances to patients?
-can be removed for cleaning and sports/hobbies
what are the advantages of removable appliances to orthodontists?
-cheap
-less chair side time than fixed
-good anchorage
-can move blocks of teeth
-easy to adjust
what are the disadvantages to patients?
-must be worn
-lower appliances less tolerated
-can temporarily affect speech/eating
what are the disadvantages to orthodontists?
-dependent on pt cooperation
-limited movement
-retention post correction can be difficult
what are the post op instructions for fitting removable appliances?
give verbal and written instructions:
-must be worn 24hrs/day
-can be removed for cleaning/sports/hobbies and eating if necessary
-warn of initial discomfort
-warn of initial difficulty eating/speaking
-inform pt/parent how to activate screw
-inform pt/parent who to contact if any problems
when do you review fitting of removable appliance?
-4 weeks
then every 4-6 weeks
what do you do at reviews?
-check OH
-check if any problems e.g sharp edges
-reactive active components
-teeth move approx 1mm/month
-note any speech problems
-check signs of wear
-encourage pt
what are common problems seen at review of removable appliances?
-wear
-breakages
-appliance is loose
-poor pt compliance
-excessive tilting (spring in wrong position)
-candida infections
- poor OH- canidida and gingival inflammation
what kind of patients do functional appliances require?
-good OH
-good compliance
-pre-adolescent growth phase
what are the contra-indications of functional appliances?
-poor OH
-poor motivation
-non-growing pt (>15/16)
give an example of a fixed functional appliance
Herbst appliance
name a removable functional appliance
twin block appliance
what are advantages of twin blocks?
-removable for cleaning
-may avoid extractions
-may accelerate growth
-may reduce incidence of trauma
-may reduce complexity of tx needs
-effective for class II malocclusions
what are the disadvantages of twin blocks?
-affect speech and eating
-bulky appliance
-may cause ST trauma
what are fixed appliances?
-made of brackets and wires
-attached to the tooth- cannot be removed by pt
-appliance moves teeth by wire and its interactions with bonds/brackets
what are orthodontic wires made of?
-nickel titanium
-stainless steel
what shapes do orthodontic wires come in?
-round
-rectangular
name some fixed appliance types
-labial/lingual fixed appliances
-TPA
-QUAD HELIX
-RME
-TADS
what kind of pt is suitable for fixed appliances?
-good OH
-free from pathology/disease
-motivated pt
-IOTN-suitability
what are the contraindications of fixed appliances?
-poor OH
-poor motivation/attendance
-pathology/disease
-pre-existing root resorption
what are the advantages for fixed appliances?
-full range of tooth movements are possible
-provides optimal tooth control
-flexible
what are the risk of fixed appliances?
-poor OH
-caries
-gingivitis
-periodontitis
-ST trauma
-pulpal necrosis
-root resorption
-gingival recession
what will be seen at end of fixed appliance tx?
-class I/II molars
-class I canines
-no spacing
-no rotations
-flat occlusal plane
-normal incisor angulting
-normal incisor inclination
what is essential after fixed appliances?
retainers
describe the importance of retainers?
-active phase
-retention phase
the biggest risk to orthodontics is relapse
what is the current advice for retainers?
-must be worn 7 nights/week
-removable retainers are used for life
-removable must be worn even with fixed retainer
what are the two main retainers used?
-hawley retainers
-clear plastic retainers
what do fixed retainers need?
-maintainance
-removable retainer
do clear plastic retainers require follow up?
yes in primary care- won’t last a lifetime and can be remade by gdp
what orthodontic emergencies can be treated by therapists?
-broken removable retainer-can be remade
- all other removable appliances need referred
-wire out- can be cut in emergencies then referred
-all other problems with fixed appliances should be referred.
what should you do if patients bracket has debonded?
-cover with wax to secure and refer
if pt’s wire comes out of tube, what should do?
-rewire if skilled and cut wire distal to easy bracket excess
-if cutting wire-refer to orthodontists
-use wax to cover wire
