Interceptive ortho 2 - late mixed dentition Flashcards
What is a URA design to correct anterior cross bite with 21 out of line of arch?
Active - Z-spring UL1 (double cantilevered spring) 0.5mm HSSW
Retentive - Adams clasps 16,14 and 26,24 - 0.7mm HSSW
Anchorage - Only moving one tooth
Base plate - Self cure PMMA + post. bite plane
What is the digit habit management?
- Positive reinforcement
- Bitter-tasting nail varnish
- Glove on hand, elastoplast
- Habit breaker appliance (habit deterrent ) fixed or removable
Why should you treat a digit habit early?
- Maximise potential for spontaneous correction of anterior open bite whilst still eruptive potential for incisors
- fix before 9 yo whilst root formation still incomplete
- Prevent effects on vertical and transverse skeletal development which could lead to permanent skeletal change if habit persists
What URA can be used as deterrents for digit habit?
- One piece baseplate with single goal post OR
- Split baseplate with expansion screw and 2X palatal goal posts
no retention component on midline
What fixed appliance can be used as deterrents for digit habit?
- Tongue rake
How do you know if pt is wearing their appliance?
- Ask
- Did they walk into surgery wearing it?
- Can they speak with it?
- still suffering from excess salivation?
- Can they take it in and out without difficulty?
- Has tooth moved?
- Is the active component now passive
- Does the appliance still fit
- Are there any signs of wear on the appliance
- Does palate look as though appliance has been place - Gingival erythema? Palatal erythema?
What are infra-occluded teeth?
- One or more teeth fail to project as far as normal occlusal plane
What is the probability of infra-occlusion?
- 10%
- Lower > uppers
- Permanent successor absent
What is the aetiology of infra-occluding teeth?
- Ankylosis of primary tooth
- Surrounding alveolar bone continues to grow
- Primary tooth tooth gets left behind
What should you assess the radiographs for when think it’s infra-occluding teeth?
- Presence/ absence of successor
- Ankylosis of primary tooth (no PDL space/ no clear lamina dura)
- Root resorption of primary
What is the treatment for infra-occluding teeth if permanent successor is present?
- Monitor 6-12months
- Extract if primary tooth below IP contact point
- Consider XLA if root formation of successor near completion
- If XLA then maintain the space
What are the risks of doing nothing with an infra-occluding tooth?
- Permanent successor become more ectopic
- Infra-occlusion becomes worse and tipping of adjacent teeth
- Caries and Periodontal disease
What is the treatment for infra-occluding teeth is permanent successor is absent?
Depend on
- Degree of crowding
- Degree of infra-occlusion
- Any other features of malocclusion
- Retain primary if in good condition and consider onlay
- XLA if below IP contact point and plan space management
What is the treatment for plan spacing management for infra-occluding teeth if permanent successor absent?
- Either maintain space for prosthetic tooth
- Reduce space to one premolar unit (needs fixed appliance)
- Close space with fixed appliance
What is an URA design to maintain space of 25?
A - None
R - Adams clasps 16 and 26 0.7mm HSSW
Southend clasp 11 and 21 0.7mm HSSW
A - Not required
B - Extend baseplate distal to 24 or consider wire stop (0.6mm or 0.7mm HSSW) Self cure PMMA acrylic
What is the normal development of upper Canines?
- Development starts high and palatal
- Migrate and lie labial and distal to root apex of upper lateral
- 90% palpable by 11 years
When should you assess position of upper canines?
- 9-10 years
- Palpate by 11
- Mobile C’s and symmetry
- Angulation of lateral incisors
- Radiograph if unable to palpate
What can occur with ectopic maxillary canines?
- Central incisors resorb by 15%
- Lateral incisors resorb by 66.7% using CBCT
- Most root resorption occurs before age 13
What is the management of ectopic maxillary canines?
- XLA of C
- Consider if need space maintainer
- Wait 12months for eruption then reassess
When is the XLA of C’s for ectopic maxillary canines likely to be successful?
- Age between 10-13years
- Canine is distal to midline of upper lateral incisor
- Sufficient space available
- Canine less then 55° to mid-sagittal plane
What are some risks of doing nothing for ectopic maxillary canines?
- Permanent successor become more ectopic
- Permanent canine then fails to erupt (impacted canine)
- Risk of root resorption of adjacent teeth
- Risk of root resorption of canine crown
- Risk of cysts formation around canine
- Permanent canine become ankylosed (incidence increases with age)
What should you be aware of with reverse overjet?
- Is it Skeletal or is it dental?
- Is there incisor angulations
- Is it edge-edge
- Is there mandibular displacement on closing?
max degree for tooth inclination in class III correction?
max : 120
mand: 80
What is the interceptive treatment of Class III?
- Growth modification
- Camouflage with URA
What are the growth modification options for Class III?
- Enhance maxillary growth and/or reduce mandibular growth
- Do this by
- Protraction headgear +/- Rapid maxillary expansion (RME)
- Functional appliances e.g. Reverse twin block / Frankel III
- Bollard implant + class III elastics
When is growth modification in class III most successful?
- Skeletal I or only mild class III
- Maxillary retrusion
- Anterior displacement on closing
- Average or reduced lower face height
- Patient age 8-10yrs
- Needs to wear for 14+hrs per day
What implants are used for anchored maxillary protractions?
- Bollard implants
- Into bone
Why should you treat an increased overjet early?
- Risk of trauma due to incompetent lips
- Appearance (bullying, self esteem)
- More difficult to achieve correction once pt stopped growing
What is the IOTN of increased OJ?
> 6mm = 4a
9mm = 5a
What is the interceptive treatment of Class II?
- Growth modifications with functional appliances or headgear
- Restrain maxillary growth
- Promote mandibular growth
Summary of interceptive orthodontics?
Spaced primary dentition = ok
Unerupted incisors = remove ob. / space/ obs
Balance c’s = not critical
Carious lower 6’s = Take upper
Unilateral cross bites = displacement
Habits = stop before 9yrs
Infra occluded decidious teeth = wait 1yr
Canines = Look at 11
-ve OJ = Growth
+ve OJ = functional app
What is an unusual tooth movement following interceptive XLA?
- Submerging left or right lower e
- Use band and loop space maintainer
What are the digit habits outcome?
- Posterior crossbite
- Anterior open bite
- Increased overjet
- Proclined upper anteriors
- Retroclined lower anteriors
What is the maximum angulation of the incisors if we are looking to procline them?
- Max is 120° so if they are already at this we can’t do anymore
What is the maximum angulation of lower incisors?
- 80°
- If already have this then can’t retrocline them anymore
What does ankylosis of tooth mean?
- Tooth root becomes fused to underlying bone typically as result from trauma or injury
- Can prevent eruption and lead to infra-occluded teeth
- Can lead to ankylosis-related root resorption and requires extraction
