Week 7 Mani- Self correcting anomalies Flashcards
What are self correcting anomalies found in pre-dental period?
- Infantile swallowing
- Retrognathic md
- Anterior open bite
How does pts mandible often appear from birth to eruption of 1st deciduous teeth?
Retrognathic mandible
- Md lateral sulcus lies posterior to mx lateral sulcus
- Upper gum pad protrudes
What are causes of retrognathic mandible prior to eruption of teeth?
- Growth magnitude and duration greater for anterior maxilla than anterior md
- Upper anterior gum pad (intercuspid width) > lower anterior gum pad
- Mandibular undergoes largest amount of growth post-natally rather than prenatally.
How is retrognathic md prior to eruption of teeth self corrected?
Within 6-7 months by downward and forward growth of md
What are self correcting anomalies in primary dentition?
- Anterior deep bite
- Spacing
- Flush terminal plane
- Edge to edge bite
What are self correcting anomalies in mixed dentition?
- Anterior deep bite
- Md anterior crowding
- Ugly duckling stage
- End on relationship
Why is anterior deep bite present in primary dentition?
- Incisors are more upright (more vertical inclination- interincisal angle around 150°)
- Infra-occlusion of partially erupted molars
EXAM NOTE
pic may be given and we could be asked what tx is required → may just be observation
When do you correct anterior deep bite?
Wait until both upper and lower incisors have erupted completely. Approx 10 years.
Why is midline diastema present in ugly duckling stage?
Permanent canine force exerts pressure on lateral incisor which then exerts pressure on central, leading to midline diastema
9-10 year old- large front teeth, midline diastema. How to treat?
Ugly duckling stage. No need for ortho treatment. Condition will correct by itself.
3 types of spacing
- Physiologic (generalised spacing- less likely to get crowding)
- Leeway (contributes to future class I molar relationship in permanent dentition)
- Primate
Can retrognathic md during pre dental period be used as a reliable diagnostic criteria for predicting subsequent arch relationship?
No. But if A-P dimension of gum pads is greater, the possibility of child developing malocclusion is greater
What does anterior open bite and retrognathic md help with in pre dentate children?
Helps in suckling
How does anterior open bite in pre-dental child present?
Upper and lower gums pads are approximated
- Contacts only at molar region
- Space exist in anterior region
How is anterior open bite in pre dental child self corrected?
At 6-7 months by eruption of primary incisors
What is infantile swallowing?
Different from mature swallowing
- Nipple drawn into mouth
- Tongue protrudes between nipple and lower lip
- Milk is directed to pharynx
- Milk passes between faucial pillars and lateral channels of pharynx
- Excess milk dribbles down chin
What are features of infantile swallowing outlined by moyer?
- Jaws are apart- tongue placed between upper and lower gum pads
- Md stabilization by contraction of muscles of facial nerve and interposed tongue
- Swallow is guided and controlled
How is infantile swallowing self corrected?
- Gradually disappears with eruption of teeth and as infant beings to eat solid food (approx 1st year)
- When tongue is contained within dental arch, it indicates onset mature swallowing
Why does tongue go between anterior region of gum pads during infantile swallowing?
To swallow, anterior open bite needs to be closed. This is achieved by placing tongue between gum pads during swallowing
What is adults vs primary interincisal angle?
- Adult: 123°
- Primary: 150°
What is anterior deep bite in primary dentition corrected by?
- Complete eruption of primary molars (inc VDO)
- Attrition of incisal edges
- Forward and downward growth of md
What are physiological spaces in primary dentition mx and md?
- Mx: 4mm
- Md: 3mm
What do spaces indicate and what are they good for?
- Spaces are important for normal development
- Spaces can be used for adjustment of permanent successors which are always larger
- Absence of spaces indicates crowding may occur in permanent dentition
How are spaces in primary dentition self corrected?
- Eruption of larger permanent successors
- Eruption of 1st permanent molar (early mesial shift)
What are the 3 primary molar relationships?
A. Flush terminal plane
B. Distal step terminal plane
C. Mesial step terminal plane
How are primary molar relationships self corrected?
Mesial eruptive force of first permanent molar
- Early mesial shift: using primate spaces
- Late mesial shift: using leeway spaces
How do the 3 different primary terminal planes predict permanent molar relationship?
- Flush terminal plane → class I (56%), class II (44%)
- Mesial step → If <2mm, class I likely. If >2mm, class III likely
- Distal step → class II likely
How does edge to edge bite happen in primary dentition?
By downward growth of md, over jet decreased gradually
How is edge to edge bite in primary dentition self corrected?
- Eruption of permanent incisors
- Having more labial inclination (interincisal inclination 123°)
Why is anterior deep bite present in mixed dentition (6-12/13yrs)
Due to large permanent successor incisors
How is anterior deep bite self corrected in mixed dentition?
Complete eruption of primary molars increase vertical dimension
Why is mandibular anterior crowding present in mixed dentition?
- Disproportion between tooth size and arch length
- Caused by exchange of larger permanent md incisors in narrow lower arch
How is md anterior crowding self corrected in mixed dentition?
- Increased intercanine width by jaw expansion
- Tongue pressure can cause forward migration of lower incisors
How does minor vs moderate crowding resolve?
- Minor: resolves spontaneously by development
- Moderate: use of leeway space (preventing mesial movement of permanent molar)
What is ugly duckling stage?
- Seen at 8-11 years of age and indicates unaesthetic appearance of child
- Centrals appear huge (let them know it is relative appearance)
- Difference in dimension of primary and permanent teeth (permanent centrals and laterals, primary canines and molars)
How is ugly duckling stage self corrected?
Complete eruption of permanent maxillary canine
What is end on end relationship in mixed dentition?
- B cusp tip of permanent mx 1st molar coincide with B cusp of permanent md 1st molar.
- Obtained in mixed dentition period following flush terminal relation in deciduous dentition
What is end on end relationship in mixed dentition self corrected by?
- Eruptive force in M direction of permanent md molars
- Late mesial shift in non-spaced dentition
What is the likely permanent relationship that will come from end to end relationship in mixed dentition?
- 75% shift toward class I relationship
- 25% shift into class II relationship
What are self correcting anomalies in permanent dentition?
Increased overjet and overbite
