Interceptive Orthodontics 1 Flashcards
Define interceptive orthodontics.
Any procedure that reduces or eliminates the severity of a developing malocclusion.
What are the key stages covered in interceptive orthodontics?
- Early mixed dentition
- Late mixed dentition
What is the sequence of eruption for permanent teeth
• 6’s → 6 years
• 1’s → 7 years
• 2’s → 8 years
• 4’s → 10 years
• 3’s & 5’s → 11-12 years
• 7’s → 12-13 years
What is ectopic eruption of the first permanent molar?
When the permanent first molar gets stuck beneath the primary second molar (‘e’) and fails to fully erupt.
What are the management options for an impacted first molar that does not self-correct?
• Orthodontic separator
• Attempt to distalise the first molar
• Extract the primary second molar (‘E’)
• Distal disking of the primary second molar (‘e’)
What factors can cause an unerupted central incisor?
• Supernumerary teeth
• Trauma to primary teeth → dilaceration of the permanent tooth
• Pathology or developmental anomaly
• Congenital absence (rare)
How is a case of an unerupted central incisor assessed?
- Case history – especially trauma history
- Extra-oral assessment
- Intra-oral assessment – check retained primary tooth for mobility/discoloration
- Space availability assessment
- Radiographs – Anterior occlusal or periapical
What are the treatment options for an unerupted central incisor?
- Remove any retained primary teeth & supernumeraries
- Create/maintain space
- Monitor for 12 months if patient <9 years (immature root apex)
- If the tooth fails to erupt or patient is >9 years (mature root apex) → surgical exposure & orthodontic traction
What are the two types of surgical exposure, and which is preferred for a maxillary incisor?
• Closed exposure (preferred): Mucoperiosteal flap raised, gold chain bonded to the palatal surface, flap replaced.
• Open exposure (rare): Simple elliptical flap over the tooth, used for soft tissue-only impactions.
What factors influence the effect of early primary tooth loss?
• Degree of pre-existing crowding
• Age of the patient
• Arch (maxillary vs. mandibular)
• Specific tooth lost
Define and explain the purpose of balancing and compensating extractions.
• Balancing extraction: Removal of a contralateral tooth in the same arch to preserve the midline.
• Compensating extraction: Removal of the opposing tooth in the opposite arch to preserve buccal occlusion.
How does early loss of different primary teeth impact occlusion?
• A’s and B’s: Little impact, no balancing or compensating needed.
• C’s: Balance if necessary.
• D’s: Small centreline shift; consider balancing (more likely if crowded).
• E’s: Major space loss (upper > lower), consider space maintenance.
What is the consequence of early loss of a lower ‘E’?
Mesial drift of the first permanent molar (6), leading to space loss.
What are the types of space maintainers?
• Removable: Passive URA (with clasps, labial bow, acrylic baseplate, and optional mesial stops).
• Fixed: Palatal and lingual arches, band and loop.
What factors influence the decision to extract first permanent molars?
• Age/dental development stage
• Degree of crowding
• Malocclusion type
• Condition of other teeth
• Patient’s ability to tolerate complex dental care (GA vs. LA)
• Availability of orthodontic services
• Willingness of child and parent to engage in long-term care
When is the best time to extract a poor prognosis first molar for the best outcome?
• Second molars’ bifurcation is calcifying
• Third molars (8’s) are present
• Lower second molar has mesial angulation
• Class I or reduced overbite
• Moderate lower crowding and mild/moderate upper crowding
What considerations should be made for balancing first molar extractions?
• If extracting a lower 6, consider extracting the upper 6 only if it will remain unopposed for a prolonged time.
• If extracting an upper 6, the unerupted upper second molar can drift mesially into place.
• Do not balance with a sound tooth unless an occlusal reason exists.
How do you assess a posterior unilateral cross-bite?
- Check for displacement on closure
- Determine IOTN score
- If IOTN ≥ 4c and displacement >2mm, treat
What is the recommended approach for treating posterior cross-bites?
• Overcorrect the cross-bite
• Use a removable appliance (e.g., hyrax screw or coffin spring)
• Use a posterior bite plane to disclude the teeth
• Retain for 3 months post-treatment
What are the indications for early anterior cross-bite correction?
• Displacement
• Mobility of lower incisors
• Tooth wear
• Gingival recession
What type of appliance is used for anterior cross-bite correction?
Removable appliance with a Z-spring (double cantilevered spring) and clasping for retention.
What factors influence the stability of cross-bite correction?
• Anterior cross-bites: Stability depends on overbite and growth.
• Posterior cross-bites: 50% relapse rate.
Why should oral habits be corrected early?
• To allow spontaneous correction of anterior open bite while incisors still have eruptive potential (8-10 years).
• To prevent skeletal changes in vertical and transverse dimensions.
What are common approaches for digit habit management?
- Positive reinforcement
- Bitter-tasting nail varnish
- Glove or elastoplast on the hand
- Habit breaker appliance (fixed or removable)
Name two types of habit-breaking appliances.
- Palatal goal post appliance
- Tongue rake (fixed or removable)
What instructions should be given to patients when fitting a removable appliance?
Wear full-time
• Keep both teeth and appliance clean (brush at least twice a day)
• Use daily fluoride mouthwash
• Avoid sugary, hard, and sticky foods
• Speech may be affected initially
• Expect excess salivation and mild discomfort initially
• Contact the dentist if experiencing problems
How can you assess if a patient is wearing their appliance?
• Ask them!
• Observe if they walked in wearing it
• Check their speech
• Look for signs of excess salivation
• Check for appliance wear
• Inspect the palate for erythema
• Check if active components are now passive
• Confirm fit of the appliance
Summarize key management principles for early mixed dentition.
• Spaced primary dentition: Normal
• Unerupted incisors: Remove obstruction, create space, observe
• Impacted 6’s: Observe 6 months or intervene
• Balance ‘C’ extractions if needed
• Carious lower 6’s: Refer for assessment
• Cross-bites: Check IOTN and displacement
• Habits: Stop before age 9
