Lecture 10 Flashcards by Shauniell Frazier Dearing

when extraoral force is applied to the maxillary teeth, where is the force effective?

sutures of maxilla

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What does occipital pull head gear do to growth?

restricts max growth in anterior-posterior and vertical demensions

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in what class would restriction of growth in the maxilla be beneficial?

class II

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what are the two general philosophies for implementing max. expansion?

1-fixed expansion

2- removable expansion

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4 negative effects from using removable expansion appliances

1-apical and crestal stress in anchor teeth is higher
2-higher stress in cortical and spongy bone from forces produced against hard palate and alv. bone
3-vertical displacement (crown tipping) of molar cusps
4-poor patient compliance

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what are the 2 internal rotations of the mandible?

1- rotation around the condyle (matrix rotation)

2-rotations centered within body (intra matrix rotation)

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T/F over time mandibular plane increases

False. body of mandible rotates (up anteriorly, down posteriorly)

*rotation of around condyle or centered within mand. body

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What makes the mandible more challenging to expand?

there is no mandibular suture

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T/F moving lower incisors is problematic for stabilty

True.

*lip pressure increases too much

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What area of the mandible is the only one that can be expanded and maintain stability?

expansion across the premolars

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expansion for canines and maintain stability

0-1mm

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expansion for premolars and maintain stability

1st premolars: 2mm

2nd premolars: 2-3mm

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expansion for molars and maintain stability

3 mm

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T/F the mandible can be pushed and pulled the same way the maxilla can to alter growth

False. The TMJ is difficult to transfer force through

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what is the main problem for the cupping device?

it has to be worn 24/7 and kids just wont do that.

It also runs the risk of tilting incisors lingually

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what is the purpose of the delaire-type facemask, AKA reverse pull headgear?

enhance A-P maxillary growth in a class III px

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mechanism the Delaire-type facemask works

1-pulls maxilla while pushes mandible

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3 effects of Delaire-type face mask

1-some forward max. movement
2-forward movment of max. teeth
3-downward and back rotation of mandible

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it is easier to restrain or stimulate mandibular growth?

stimulate

*mandible can be pulled into protrusion and held for long duration with moderate force

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when do you know true stimulation of mandibular growth has occurred?

when on the growth chart you see faster than normal growth that continues thereafter

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how do functional appliances move the dentition? (2)

1-repositioning the skeletal bases, placing force on teeth by stretching the muscles and tissues
2-changing occlusion relationships and therefore occlusal forces on teeth

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what is the threshold needed to move a tooth?

6 hours

*may or may not also apply to sutures

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when is the best time to wear functional appliances?

sleeping hours

*longer than 6 hours and HGH is being released

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Treating a deficient mandible can be treated in what 3 ways

1-modify growth
2-ortho camouflage
3-surgery

*teach px the pros/cons of each and that they may yield slightly different resutls

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in phase 1 ortho, what area is one of the most actively adaptable areas of bone growth?

alveolar process * between primary and adult dentition * idea for ortho

what are the 2 aspects of the mixed dentition stage?

1-utilize arch perimeter | 2-the adaptive changes in occlusion that occur during transition of one dentition to another

what makes phase 1 ortho limited?

it can only occur in the presence of at least 1 primary tooth

how long does phase 1 ortho usually last?

6-12 months

what 3 things does phase 1 ortho do?

1-corrects existing abnormalities 2-creates conditions where the dentition can function and developing normal 3-final primary teeth are lost and perm. erupt

When does the American Association of Ortho recommend every child receive ortho eval and pano?

before age 8

when can a pt move on to phase 2 ortho?

after phase 1 and after all primary teeth are lost *around 11 or 12

what are 4 reasons to refer your patient for early ortho?

1-crowding 2-abnormal growth and development 3-ectopic eruption and impactions 4-traumatic occlusion/crossbites

phase 1 (early) ortho can help correct what 3 things?

1-abnormal growth 2-abnormal habits 3-fix things that may result in trauma

what 3 things can phase 1 ortho help correct regarding possibility for trauma

1-severe deep bites 2-cross bites 3-protruded maxillary incisors

T/F anterior crossbites in primary dentition is common

False. Anterior cross bites in primary dentition indicates a skeletal growth problem * same with class III * mandibular growth lags

what types of abnormal habits can phase 1 ortho help?

mouth breathing, finger sucking, tongue position posture

What is the most basic sign of future crowding?

Lack of inter-dental spacing in the primary dentition

the maxillary anterior primary teeth are what % smaller than their perm. successors?

75% smaller

mandibular anterior primary teeth combine to be how many mm smaller mesio-distally than their successors?

6 mm smaller

T/F arch perimeter does increase after eruption, however it is a small increase in the maxilla and essentially non-existent in the mandible

TRUE

T/F because of arch growth, it can be relied upon for further dental alignment to alleviate crowding

FALSE *arch growth is not sufficient for that

what 3 things are used to create space in mandible for mild crowding?

1-increase arch width across canines 2-labial positioning of the central and lateral incisors 3-distal shift of perm. canines when primary molars are lost

what is leeway space?

size differential between primary molars and perm premolars *AKA E space

how big is mandibular leeway space on each side?

2.5 mm

how big is maxillary leeway space on each side?

1.5 mm

what is the mesial distal diameter of the maxillary perm. teeth?

128 mm

what is the mesial distal diameter of the mandibular teeth?

126mm

the maxillary arch is aprox. how many mm larger than the mandibular arch?

2 mm

flared maxillary incisors (ugly duckling stage) may cause waht?

impacted canines

what percent of 11 year olds have diastemas?

49%

what 4 things can cause a diastema?

1-tooth size discrepancy 2- mesiodens 3-abnormal frenum 4-a normal stage of deveopment

what event may cause a diastema to close on its own?

eruption of perm. canines

what size of diastema has the greatest chance of closing on its own?

less than 2mm

what does premature loss of the primary canines reflect?

insufficient arch size in the anterior region

During eruption sometimes the lateral incisors impinge on _______ causing them to ______ and be lost

canines, resorb

what happens if only 1 canine is missin?

the midline will shift

what are 3 options for maxillary crowding?

1-expansion 2-limited ortho on 1st molars and incisors 3- extract primary canines to create space

when can palatal expansion be done?

any time prior to the end of the adolescent growth spurt

what are the 4 reason for early palatal expansion?

1-stop mand. shifts on closure 2- space of erupting max. teeth 3-lessen arch distortion and tooth abrasion interferences on anterior teeth 4- reduce mandibular skeletal asymmetry

what 3 options are available for mandibular crowding?

1-expansion (no suture to expand, but lip bumpers/schwarz may help) 2-limited ortho on mand. perm. teeth 3-extract primary canines to create space

T/F class III are easy to control

False *limited ortho, reverse pull head gear

T/F early treatment is really helpful for class II

FALSE. early tx is no more helpful than just regular phase 1

ectopic eruption of the perm. 1st molar can cause resorption of the primary 2nd molar and requires _________

active intervention * impacted molar is susceptible to decay * may need to extract primary tooth

if ectopic eruption of 1st molar occurs what 2 options besides extraction might be called for?

1-spacer between them | 2-active ortho

permanent teeth often erupt in abnormal positions due to _____________

over retained primary teeth

perm. teeth normally move in what 2 directions while erupting?

occlusally an buccally

_____ is when 2 tooth buds fuse together to make one large crown

Fusion * 2 independent pulp chambers and roots * count teeth 1 less than normal

__________ is when one tooth bud tries to divide into 2 teeth

gemination * normal tooth count * 2 pulp chambers, 1 root