Spacing Solutions Flashcards
What is the ideal amount of force for orthopedic changes with headgear?
250-450 g per side
What is the ideal amount of force for tooth movement with head gear?
100-200 gm per side
What are the 3 types of pull with headgear on the maxilla?
1-Occipital pull (restricts interior and anterior growth)
2-Cervical pull (restricts superior and anterior growth)
3-Combination pull (restricts anterior maxillary growth)
The mid palatal suture becomes increasingly ______ and _____ with age
tortuous and interdigitated
What are the three categories of crossbites?
1-Dental (teeth erupted into crossbite)
2-Functional (cusps cause shift to achieve max intercuspation)
3-Skeletal (normal dentition)
What are 6 methods of correcting crossbite?
1-Hyrax appliance 2-Haas appliance 3-Hawley removable expander 4-quad-helix 5-w arch 6-Transplantal arch
Midpalatal expanders separate more in the ______ than in the _____ and usually result in ____ to ___ amount of space
Anterior
Posterior
5 to 15 mm
Which type of expansion devices produce higher stress in both cortical and spongy bone from forces against the hard palate and alveolar bone?
Removable expander
*can also cause crown tipping and higher apical and crystal stresses
The outcome of rapid versus slow expansion looks very different at ___ weeks but similar at __ weeks
2
10
*Rapid has more skeletal expansion initially
The mandibular plane angle tends to ____ with growth
Decrease
*Due to up rotation anteriorly and down posteriorly. can be around condyle or centered within the body
Moving mandibular incisors forward more than what may cause stability issues?
2mm
canines are _____ stable if expanded however expansion across premolars and molars ____ be stable if not overdone
not
can
*2mm 1st premolar, 2-3 mm 2nd premolar, 3 mm molars
Though children won’t do it because of the full time wear demands, what method remodels the TMJ joint and restrains mandibular growth?
Chin cup appliance
A delaire-type facemark does what?
pulls maxilla forward in class III patients like a reverse pull headgear
True growth stimulation results in what?
A larger mandible at the end rather that growth acceleration which results in the same size eventually but bigger initially
The frankel, bionator and activator, clark twin block and herbst appliances are all examples of what?
Functional orthodontic appliances that changes soft tissues or occlusion
What is the threshold for duration to move a tooth?
6 hours
Phase 1 treatment is performed before all primary teeth are lost and last how long?
6-12 months
The American Association of Orthodontists recommends every child be evaluated for orthodontics by what age?
8
Which permanent teeth tend to have the most crowding as the mandibular arch forms?
Mandibular incisors for about 2 years from when they come in
What three sources contribute to additional space to align mandibular incisors?
1-Slight increase in arch width between canines
2-Slight labial position of incisors
3-Distal shift of canines
What is the space called that results from the difference in larger primary molars and permanent premolars?
Leeway space or E space
*mand 2.5 mm each side. Max 1.5 mm each side
What is the mesial distal diameter of the maxillary and mandibular permanent teeth respectively?
Max-128 mm
Mand-126 mm
What age is the “ugly duckling” stage?
Around age 9
*flared max incisors may result in impacted canines
A maxillary central diastema of what size or less usually closes on its own?
2 mm
Premature loss of primary canines reflects what?
Insufficient arch size in the anterior region
*laterals cause canine to resorb
Palatal expansion should be done before what?
Adolescent growth Spurt
The most rapid loss of A-P distance in the arch is usually due to what?
Loss of the primary second molar
*a space maintainer should be placed
You do not need a space maintainer if a permanent successor will erupt within what time frame?
Within 6 months
Which type of space maintainer has a blade portion that extends 1 mm below the mesial marginal ridge of the erupting permanent tooth to guide its eruption?
Distal shoe
What are the two types of expansion?
1-Dental
2-Skeletal
What three things should be considered for dental crowding?
1-Esthetics (lip support)
2-Stability (boney support, force equilibrium)
3-Periodontal health
an arch length discrepancy less than what is a contraindication for extraction?
4 mm
An arch length discrepancy between ____ and ____ can be an extraction or non-extraction
5 and 9 mm
Arch length discrepancies of what or more almost always require extraction?
10 mm
Bi-maxillary protrusion causes what facial profile?
Convex
*all four premolars can be extracted to bring teeth back and allow lips to relax
The method of extracting primary teeth and some permanent teeth to guide the remaining teeth into normal occlusion is called what?
Serial Extraction
What are two claims of detrimental facial alteration of extraction cases?
1-Flat lips, sunken/retracted incisors
2-Narrow arch widths with large buccal corridor
Orthodontics can be used to create what for implants?
Good alveolar bone
*canines into lateral position and then moved
Using the central incisor as a reference, what are the normal dimensions of a lateral incisor?
- 2/3 the width
- 80% of the length
- 0.5-1 mm lower gingiva
Behind third molars, what is the second most commonly impacted or displaced tooth?
Maxillary Canines
*0.8-2.45 of US population, More females, 90% unilateral
What are 3 surgery types for uncovering impacted maxillary canines?
1-Gingevectomy
2-Apically positioned flap
3-Closed eruption technique
Where should the oral surgeon bone to the impacted canine so that it can be moved in to place through keratinized tissues?
buccal surface or as close to the occlusal tip as possible
Ectopic eruption of canines may cause what?
Root resorption of lateral incisors
*25% increase in eruption angle increases risk 50%
What three analysis help lead to a proper diagnosis?
1-Cast (symmetry, space, occlusion)
2-Photographic
3-Cephalometric
What are four factors to consider when developing a treatment plan?
1-Timing of tx
2-Complexity/duration
3-Predictability
4-Goals of pt and parents
What three things are evaluated when analyzing Casts?
1-Occlusal relationship
2-Tooth size, shape and morphology
3-Overjet, overbite and open bite
Available space is measured from where to where?
Mesial of one first molar to the mesial of the other over the buccal cusps and incisal edges
How do you determine space using the mixed dentition analysis?
1/2 mesiodistal width of the 4 mand incisors plus canine and premolar space
What is the width added to each quadrant for mandibular canine and premolars?
10.5 mm
What is the width added to each quadrant for Maxillary canine and premolars?
11 mm
Bolton calculated that the mesio-distal dimension of lower teeth must equal what percentage of upper teeth?
91%
*M-D dimension of lower anteriors must be 77% of upper anteriors
What does the lower third of the face contain?
- Corners of the mouth (1/3 of the way between base of nose and chin)
- Chin and lower lip (occupy 2/3 of lower third)
A proportional face is diveded into how many front planes?
5
Interpupillary distance should equal what distance?
Width of mouth
What are three ways that bimaxillary dentoalveolar protrusion is seen?
1-Excessive lip separation at rest (greater than 4 mm)
2-Excessive effort to close lips (chin dimpling)
3-Prominence of lips in profile view
Chin-Throat angle closer to what is best?
90 degrees
The nasiolabial angle should be what?
Slightly obtuse or perpendicular
What percentage of visible tooth width is ideal as you go posterior?
62% of tooth mesial to it
The width of a tooth should be about what percentage of its height?
80%
The Zenith or height of contour should be just distal to the midline on which teeth?
Central incisor and canine.
*it is at the midline on laterals
Hand wrist radiography can help determine physiologic age, specifically what bones are looked at’?
Ulnar sesamoid or Hamate bones
What three major cephalometric superimpositions are used in orthodontics
1-On the anterior cranial base (SN line)
2-On the Maxilla (contour of palate behind incisors)
3-On the mandible (inner surface of and symphysis)
SNA greater than 82 shows a?
Max prognathism
*less is max retrognathism
SNB greater than 80 shows a?
mand prog
*less is and retronagnathism
ANB is normally what?
2 degrees
*class II is greater than 4. Class III is less than 0
SNA is the sella nasion line relationship to the deepest point of what?
Maxilla
SNB is the sella nasion line relationship to the most posterior portion of what point of what?
Mand Symphysis
ANB is the angle between point A B and what?
Nasion
