First Semester Flashcards
What is the difference between the primary and secondary palate, and how do they form embyologically? Discuss which branchial arch they come from and the cartilage areas in them.
Primary palate is derived from the 1st pharyngeal arch. It forms at weeks 4-5 by the fusion of the medionasal and frontonasal processes.
Secondary palate is fusion of maxillary process shelves at 7-8 weeks.
Derived from the first branchial arch which is part of the viscerocranium
Derived from the first pharyngeal arch and are formed from intramembranous ossification
Primary epithelial band, odontogenic epithelium
The primary palate is derived from the ___ pharyngeal arch. It forms at weeks ___ by the fusion of the __ and ___ processes.
First
4-5
Medionasal and Frontonasal
The secondary palate forms at ___ weeks by the fusion of the ___.
7-8 weeks
Maxillary process shelves
The primary and secondary palate is derived from the ___ pharyngeal arch and are formed by ___ ossification
First
Intramembranous
From which branchial arch does the mandible grow from and how does the cartilage form in the mandible?
The mandible is derived from the first pharyngeal arch, specifically Meckel’s cartilage. Intramembranous ossification occurs lateral to Meckel’s cartilage and starts at the incisive or mental branches of the IAN
In regards to the cranial base, the basicranium is the template for…
The face. It helps establish the shape and perimeter of the face.
How does the calvaria and cranial base grow?
As the brain expands, the separate bones of the calvaria are correspondingly displaced in an outward direction
Primary displacement causes tension in the sutural membranes -> depositing new bone on sutural edge and enlarging in circumference
During growth, the bones of the calvaria become flatter
The calvaria is resorptive on the cranial floor and depository on endosteal surface
Cranial base is primarily resorptive on cranial floor (fossa). A/P growth occurs via growth and synchondroses
During growth, the bones of the calvaria become ___
Flatter
The cranial floor is [resorptive/depository], whereas the endocranial surface of the calvaria is predominantly [resorptive/depository].
Resorptive
Depository
What is the spheno-occipital synchondrosis and its importance?
The spheno-occipital syncondrosis provides elongation of the midline of the cranial floor (IE allows the cranial floor to expand with the brain).
It is the principle growth cartilage
Define cranial base growth spurt for both boys and girls
Rate of growth of the cranial base exceeding that in the preceding annual interval by at least 0.75mm for boys and 0.5mm for girls
When do the cranial base growth spurts occur for boys and girls?
Female: 11.6yo
Male: 13.2yo
Occurs 1.6 years earlier in females. Mandibular spurt occurs at the same time
How can orthodontics affect cranial base growth?
It has no effect
What is the importance of the cranial base in growth and how does it grow differently in class 1 and class 2 skeletal patterns?
Cranial base is important in growth in that it provides a template for the face. However, it does not grow much differently in class 1 or class 2 skeletal patterns.
What are the 3 evolutionary growth theories and the names associated with them? Where did the theories place the emphasis on growth control (which tissues)?
Genetic blueprint theory - genes control everything
Nasal septum theory - nasal cartilage (cartilage is pressure tolerant and thought capable of driving the maxilla downward and forward).
Functional matrix - genic and epigenetic tissues. Stimuli from growth and function
Discuss the functional matrix theory of growth in the format of what has been added with the most recent research as well as its general premise, genetics and environment.
Can be summarized as “form follows function”, but on a much deeper level, it goes beyond soft tissues driving form. Rather, it is an interplay between genetics (which provide the building blocks) and epigenetics (environment) to provide a phenotype.
General premise: not just soft tissues. Periosteal matrix = muscle and bone. Capsular matrix = neurocranial capsule and orofacial capsule
Genetics and environment: genomic and epigenetic factors are both necessary causes. Neither is sufficient alone, as causative factors
In regards to mandibular And maxillary growth, what are the clinical targets in growing people?
Mandible targets = ramus, condyle, alveolar process
Maxilla targets = Maxillary tuberosity, sutures, alveolar process
The ramus remodels in a ___ manner. It is resorptive at the __ border and depository at the ___ border. The ___ is its counterpart. It [can/cannot] be affected orthodontically.
Anterior/posterior
Anterior
Posterior
Middle cranial fossa
Cannot
The condyle requires ___ growth, yet it is __, ___, and grows in the direction of ___. How well is it affected orthodontically?
Endochondral
Adaptive, multidirectional, articulation
This is the site of growth in the mandible that we can affect most with orthodontic treatment albeit limited (Class 2 and class 3 correctors)
The lingual tuberosity grows in a __ direction but is augmented by ___ fields of the lingual fossa. How well is it affected orthodontically?
Posterior
Resorptive
Cannot be affected orthodontically
Which part of the mandible (besides the alveolar process) can be affected the most with orthodontic treatment?
The Condyle. Although orthodontic treatment has a very limited affect on growth of the condyle
Growth of the maxillary tuberosity causes ____. How can orthodontics affect growth here?
Horizontal lengthening of maxilla (deposition)
Nothing we can do to affect/create more bone (IE cant move teeth into tuberosity and expect to make more bone; the bone has to already be there)
Describe the relationship between growth and sutures in the maxilla.
Theory is that downward and forward growth of the maxilla is caused by tension placed in the sutures. Tension can be created/increased orthodontically with RPE, Headgear, Facemask
Describe the growth that occurs in the alveolar process. How can orthodontics affect this?
Vertical drift occurs here
We readily manipulate the alveolus with all sort of appliances including the straight wire appliance
How does the lingual tuberosity form during growth?
Equivalent of maxillary tuberosity
Growth straight distal with slight lateral shift
Allows maxillary and mandibular posteriors to stay in contact.
What are the major concepts in mandibular growth? Which way does it grow? Limits, borders, and maintenance of homeostasis.
A/P: Remodels and is displaced in a downward and forward fashion. Technically grows up and back to maintain articulation with glenoid fossa. Ramus remodeling.
Transverse: Established/limited by middle cranial fossa. Follows “V” principle.
Vertical: Uprighting of ramus during growth
Explain how neuromuscular development is associated with growth and development and its effect on orthodontic treatment.
Neuromuscular development follows an antero-posterior gradient (IE lips to posterior tongue) Infantile swallow (may be maintained and thus need to be addressed) to mature swallow Maintenance of airway, infant cry, gagging, mastication, neural regulation of jaw positions Neuromuscular mechanisms and bone growth factors are far more important in nature of occlusal relationships than cuspal height/inclination or condylar guidance. Teeth must change continually to adapt to growth and neuromuscular changes.
Does malocclusion affect neuromuscular functioning? How? Name some examples.
Malocclusion affects neuromuscular functioning in cases of crossbite
Throckmorton study: pts with unilateral crossbite had longer chewing cycle on crossbite side and path was more deviated. Treatment to correct crossbite helped chewing cycle approach that of controls
What are the three head/facial forms?
Dolichocephalic (leptoprosopic)
Brachycephalic (euryprosopic)
Dineric
Describe the dolichocephalic face type and how they grow differently. How does this affect our orthodontic treatment?
Long/narrow face, retrognathic, convex facial profile, eyes deep set, aquiline nose
Grow vertically
Worried about opening these pts up because our mechanics have an extrusive nature
Describe the brachycephalic face type. How do they grow? How does this affect our orthodontic treatment?
Short/wide face, prominent chin, straight/concave profile, eyes bulging
Grow horizontally
Try to open these pts up, but have to fight against strong musculature
Describe the dineric face type.
Technically brachycephalic with leptoprosopic facial form
Long face and large nose
Ears appear closer to back of head because of cranial flattening (Cradling)
Mesocephalic-intermediate form
Describe the changes that occur in normal-growing dolichocephalic individuals.
More anteriorly inclined middle cranial fossa (obtuse angle)
Longer and more narrow anterior cranial fossa
Steeper mandibular plane/clockwise rotation of the mandible
Prominent nose, deep set eyes
Describe the growth studies associated with dolichocephaly
Nanda 1988 - dolies eyes grow more vertically, tend to have larger values for LAFH and shorter posterior face heights. Pts have a propensity for anterior open bite
Chung 2003 - growth pattern remains the same (If growing dolie, will continue to grow dolie)
Cangialosi 1984 - LAFH greater than UAFH (agrees with Nanda)
Describe the changes that occur in normal-growing brachy individuals. Describe the growth studies associated with them.
More posteriorly inclined middle cranial fossa (acute angle)
Wider and shorter anterior cranial fossa
Flatter mandibular plane/counter-clockwise rotation
Bulbous forehead, eyes appear more bulging
Nanda 1988 - deep bite pts (brachy) tend to have more UAFH
Chung 2003 - growth pattern remains the same
Why types of malocclusion tend to have orthognathic facial profiles?
Class 1 malocclusion
Class 2 div 2
Which malocclusions are typically the cause of prognathic facial profile?
Class 3 malocclusions.
Headform: brachycephalic more likely
Facial topography: short, round fat heads, protrusive mandible, concave profile
What type of malocclusion is the most likely cause of a retrognathic profile?
Class 2 div 1
Headform: dolicocephalic more likely
Facial topography: long narrow face, recursive mandible, convex profile.
There may be build in ___ features during growth, which can compensate for and help offset abnormal growth tendencies thereby produces a ___ occlusion. If the compensatory features are inadequate, ___ exists, but is generally [less/more] severe than than the abnormal tendencies might have otherwise produced if unchecked.
Compensatory
Class 1
Malocclusion
Less
Dolichofacial patients are associated with ___ bites. Brachyfacial patients are associated with __ bites.
Open
Deep
Dolichofacial pts are associated with a ___ airway while brachyfacial pts are associated with a ___ airway.
narrow
Wider
Why do malocclusions occur in each headform, dolichofacial or brachy?
Malocclusions form as a result of inadequate compensatory growth. For example, in a dolichofacial, LAFH tends to be longer than normal. To prevent an anterior openbite, posterior face height needs to keep pace, which does not happen in some cases. For a brachyfacial, the opposite can be seen; UAFH tends to be greater and LAFH does not keep pace resulting in a deep bite situation
In class 2 div 1, the lower incisors are [flared/steep]
Flared forward
In class 2 div 2, the lower incisors are [flared/steep]
Steep
In a dolichofacial patient, they have a ___ facial profile, a ___ mandible and lower lip, a ____ nose, and soft tissue tends to be ___
Convex
Retrognathic
Prominent
Thicker in a long vertical pattern
In a brachy patient, they tend to have a ___ facial profile, a __ chin, a ___ nose, and soft tissue thickness tends to be…
Straight to concave
Prominent
Less protrusive
Thinner in short facial pattern
What are the boundaries of the mandible and how are they anatomically defined?
Transverse boundary - middle cranial fossa
A/P - ramus (middle cranial fossa) and lingual tuberosity. Corpus of mandible should lie anterior to posterior maxillary plane
Vertical - condyle, ramus
What are the boundaries of the maxilla and how are they anatomically defined?
Transverse - anterior cranial fossa. Maxillary tuberosity
A/P - forward boundary is the brain. For the nasomaxillary complex - cribriform plates. Posterior boundary - posterior maxillary plane (at junction of middle and anterior cranial fossae). Maxillary tuberosity
Vertical - orientation of olfactory bulbs have an influence on how the nasomaxillary complex is oriented
According to longitudinal studies, with growth nose height ___, nose length ___, upper lip length ___, upper lip thickness ___, Lower lip length ___, lower lip thickness ___, nasolabial angle ___, chin ___
Nose height increases (more in boys)
Nose length grows equally
Upper lip length increases (more in boys)
Upper lip thickness decreases with age (according to Sarver), slightly increases (according to Prahl)
Lower lip length increases
Lower lip thickness decreases with age (Sarver), slightly increases (Prahl)
Chin increases in thickness with age
According to Bishara 1998, how does the overbite change from 5-45 yo?
Overbite: pretty stable once permanent teeth erupt. Difficult to predict the final overbite in a child (deciduous dentition). If little overbite to start then maintained in later stages of development
How does anterior face height change from 5-45yo?
Change early on more significant, get vertical change in N-ANS, N-Me throughout life
How does posterior face height change from ages 5-45?
Males>females, Ar-Go, S-Go, growth more significant early on, continuous until mid 20s
How does the relationship of AP face height change from 5-45yo?
MPA flattens with age. Small amount of vertical growth occurring in the face (N-ANS, N-Me, Ar-Go, S-Go)
What are the conclusions drawn regarding change in arch length from birth to 45yo from the Bishara study?
The greatest incremental increases in Mx and Mn arch length occur during the first two years of life
Arch length continues to increase until 13 years in the Mx arch and 8 years in the Mn arch
Following these ages, significant decreases in arch length occurred until 45 years of age. As a result, the decreases in arch length is translated as an increase in the tooth size-arch length discrepancy, unless interproximal attrition keeps pace with the decrease in arch lengths
According to the Bishara paper, how does arch width change from birth to 45yo?
Mx and Mn intercanine width increased between 3-13 years of age in both male and female subjects. After that age, it decreased and continued to do so until age 45 years in both males and females.
Intercanine and intermolar widths significantly increased between 3-13 years of age in both the Mx and Mn arches. After the complete eruption of the permanent dentition, there was a slight decrease in the dental arch widths, more in the intercanine than in the intermolar widths
Mn intercanine width, on average, was established by 8 years of age (after the eruption of the four incisors). After the eruption of the permanent dentition, the clinician should either expect no changes or a minimal decrease in arch widths
According to the Moore’s paper, how does intercanine width change with age?
The main growth phase occurred in both sexes during the incisor transition and levels off after full eruption of the lateral incisors. In the Mx, a second increase in arch breadth was noted after the emergence of the permanent canines, but this increase did not occur in the Mn.
The changes in the intercanine distances are explained by growth of the alveolar processes in the incisor region. Additionally, the changes in arch length in the maturing dentition are also a function of mesial migration of the posterior teeth.
What are the characteristics of the ugly duckling stage? What age does it occur?
4-12years
Diastema between upper incisors
Maligned lateral incisors
Large, protrusive upper incisors
Crowding in the lower incisors
Decreased available space maximum space lost/maximum crowding at this point. Normal on lower, some spacing on upper and will take a couple years to resolve
Describe the arch size/ alveolar growth increase from ages 4-12
Maxilla - slightly, between 8-10 years (after eruption of 2s) (females before males)
Mandible - significant; between 8-9yo males, 7-8 females (after eruption of 2s)
Decreased crowding or increased spacing again
Maxilla becomes slightly more spaced (especially in males) mandible remains slightly crowded but improves (especially in females)
Males have better recovery than females
Changes in arch dimensions (spacing and crowding) seem to be triggered by…
Eruption of permanent teeth
According to the Baume study - unable to accurately predict outcome of development based on ____
Deciduous dentition spacing/crowding
~___% of pts with no primary spacing resulted with normal outcomes
57% (9/16)
It is normal to have buck teeth in mixed dentition. There is typically space in upper incisors and crowded lower incisors (2-4mm). How long does this take to resolve?
About 2 years
What is incisor liability?
Permanent incisors are larger than primary incisors
Maxillary - just enough space to accomodate for larger permanent incisors
Mandible - shortage of space by 1.6 - 2mm
How is incisor liability compensated?
Resolved by widening of canines, facial eruption of maxillary incisors, and leeway space
How can early loss of deciduous teeth negatively affect incisor crowding?
Leeway space creates additional space for crowded lower incisors, if this space is lost you will have more crowded lower incisor.
True or false… there is a slight decrease in arch length upon emergence of the 6s
True
There is a small increase in arch length with eruption of the permanent incisors in the ___ arch, but negligible in the ___ arch
Maxillary
Mandibular
True or false… there is an arch length decrease after shedding of deciduous molars (especially 2nd molars)
True, especially on the lower arch
According to Bork, what are the three most stable superimposition points for the mandible during growth?
Mandibular canal
Internal symphysis
And third molar tooth germ
Failure of migration of the ____ causes treacher Collins syndrome
Neural crest cells
What bones are associated with the first branchial arch? How are they formed?
Intramembranous ossification
Premaxilla Maxilla Zygomatic bone Part of temporal bone Mandible Ossicles
What muscles are associated with the first branchial arch?
Temporalis Masseter Pterygoids Anterior belly of digastric Mylohyoid Tensor tympani Tensor palatini
What nerve(s) are associated with the first branchial arch?
Trigeminal (CN5) - forms maxillary and mandibular process (V2 and V3)
What is Enlow’s first name?
Donald
Define bone remodeling
Progressively shape and create the changing size of the bone to accommodate its various functions
Define bone displacement
Physical movement of the whole bone
When comparing the facial features of a child compared to an adult, the child’s ears appear __ compared to adult. The eyes get [larger/smaller] by proportion. The forehead is more ___. The nasal region is ___. The nasal chamber width is ___
Low
Smaller
Upright and bulbous
Vertically shallow
More narrow. (Nasal width in infant is barely the width of the nose; in an adult it expands to half-way across the orbital floor)
When comparing the facial features of a child compared to an adult, the child jaw size is smaller,and the face is ___ because…. they have a vertically ___ face. The nasal part of face is still small; primary and secondary dentition not fully established. Jaw bones not yet grown to their full ___ extent.
Broader because it is based on brain width which is larger than the face at this stage.
Short
Vertical
True or false: the mandible can continue to grow even if the condyle is removed
True. Although the condyle is an important growth site, it is not a growth center
What is the difference between basal bone and alveolar bone?
Basal bone and alveolar bone are similar in composition. The difference is alveolar bone houses the teeth and is easily modified by orthodontic treatment whereas the basal bone is mandibular bone which does not house the teeth and is more difficult to modify with orthodontic treatment.
Females develop around ___ years earlier than males. However males tend to grow for a longer period of time and to a greater extent.
1.6 years
The ___ and ___ fuse to form the upper lip
Medial nasal process and maxillary process
At what week of gestation does the secondary palate fuse?
7-8 weeks
What are the three most predictable sites for superimposition of the mandible as mentioned from the Bjork study?
Inferior alveolar nerve
Tooth germ position of lower 3rd molar
Inner border of mandibular symphysis
Why is it important for the neuromuscular development in the face to occur early in development?
It is important for vital functions such as respiration, mastication, and swallowing
What 4 bones make up the cranial base?
Ethmoid
Sphenoid
Temporal
Occipital
The ___ that takes place on the superior surface of the basicranium and ___ that takes place on the inferior surface of the basicranium allows compartmentalizations of ___
Resorption
Deposition
Neural structures such as medulla, pons, spinal cord
When does the inter-sphenoidal synchondrosis fuse?
At birth
When does the spheno-ethmoidal synchondrosis fuse?
~age 7
When does the sphenoid-occipital synchondrosis fuse?
Primary growth site for the basicranium and allows growth of the basicranium in the AP direction
Growth continues until about 13-15 years and fuses around 20 years.
Growth of the sphenoid-occipital synchondrsis occurs until age __ and fuses at age ___
13-15
20
What are some stable landmarks used in cehpalographic analysis of the cranial base?
Sella
Nasion
In which direction(s) does the maxillary tuberosity grow?
Posteriorly, inferiorly, and laterally
What are the characteristics of a mature swallow?
Minimal contraction of lips during swallowing
Tongue tip help against palate
Teeth are together
Mandible stabilized by masticatory muscles contracting
Brachy has an ___ basicranium flexure.
Dolicho has an ___ basicranium flexure
Acute
Obtuse
According to the Hesby article (2006) about transverse skeletal changes, the greatest increase in transverse skeletal changes occurs at the ___
Jugale (superior to upper molars)
The greatest increase in intercanine width in both arches occurs when?
The first two years of life
The maxillary intercanine width increased until age ___, whereas the mandibular intercanine width increases until age___
13
8
True or false… intercanine width decreases overtime after the eruption of the canines.
True
In both arches, intermolar width is increased the greatest during the first ___ of life and increases until about ___ years of age. There is a slight increase when the ___ erupt.
2 years
13 years
Permanent molars
Describe the vertical dimension increase in the following ages: 5-10: 10-15: 15-25: 25-45:
5-10 = 11mm
10-15 = 10mm
15-25 = 4-5mm
25 - 45 = 1-2mm
How does posterior vertical dimensional growth differ from anterior?
The posterior facial height grows in a similar fashion except it grows for a longer period of time contributing to the 2-3mm decrease in the MPA overtime.
The MPA [increases/decreases] approximately ___ overtime due to posterior facial growth that occurs for a [shorter/longer] period of time than the anterior facial growth.
Decreases
2-3mm
Longer
Describe the end-end molar relationship in the primary dentition and what it will result in the permanent dentition.
Upper and lower primary second molars in a flush terminal plane
Tendency is to become class 1 molar relationship (however about 20% will become class 2)
Describe the mesial step molar relationship in the primary dentition and what will result in the permanent dentition.
Lower primary second molar is mesial to the upper primary second molar
Tendency to become class 3 or class 1
Describe the distal step molar relationship seen in the primary dentition and what will result in the permanent dentition.
Lower primary second molar is distal to the upper primary second molar
Tendency to become class 2 or class 1
Describe the overjet and overbite changes seen in the transition from primary to permanent dentition.
Overbite and overjet changes are unpredictable.
When comparing the facial features of a child compared to an adult, the child’s ears appear [high/low], the eyes will get [larger/smaller] by proportion with growth, the forehead is ___, the nasal region is vertically [shallow/deep].
Low
Smaller
Upright and bulbous
Shallow
When comparing the facial features of a child with an adult, the nasal chamber in a child is ____. The child face is ___ because…
Major differences start during ___
Barely the width of the nose. In an adult it expands to halfway across the orbital floor
Broader because it is based on brain width which is larger than the face at this stage. Also the child has a vertically short face. The nasal part of the face is still small; primary and secondary dentition is not fully established; jaw bones are not grown to vertical extent
Puberty (pre-pubertal face is very similar for males and females)
In regards to the V principle of growth in the mandible. Where does the resorption and deposition occur?
Resorption occurs on exterior, deposition occurs on interior of the V
At what age is corpus and ramus remodeling conversion thought to be complete?
7.10
The ___ is the mandibular equivalent to the maxillary tuberosity
Lingual tuberosity
What is a common complication from insufficient mandibular growth?
Impacted third molars
What bones make up the nasomaxillary complex? (8 bones)
Nasal Ethmoid Maxilla Vomer Zygomat Lacrimal Palatine Nasal
What is the major growth site of the maxilla?
Maxillary tuberosity
What suture is key and a growth mediator for the nasomaxillary complex?
Lacrimal suture
True or false… according to the Lewis (1985) article, the mean age of occurrence of the first pubertal spurt is the same in males and females
False. It occurs about 1.6 years earlier in females
True or false… from the Lewis 1985 article: the beginning of growth to precede the peak height velocity occurs by about half a year in both sexes
True
What four bones contribute to the cranial base?
Ethmoid
Sphenoid
Temporal
Occipital
In humans, having sight angle at right angle to spinal cord allows for what things?
Close up vision Upright posture Ability to see hands with both eyes Enhanced vision and depth of field Allow for tool/weapon use (All of the above)
What features from primary dentition remain stable during transition to permanent dentition
Primary canine in 90% of cases remained class 1
At what age is the most significant maxillary and mandibular anterior and posterior arch width growth?
6 weeks to 2 years old
Explain why there is typically a decrease in arch depth (length) with growth.
Leeway space lost due to mesial drift of permanent first molars
Increasing curve of spee
Crowding
Interproximal attrition
The cranial base growth spurt occurs about __ earlier than PHV, and ___ earlier than menarche. It typically occurs ___ [before/after] ulnar seasmoid ossification
- 5 years
- 5 years
- 6 - 1.3 years after
According to Bjork and Skieller, there is a [decrease/increase] in palatal width [greater/less than] the increase in molar width. Why is this important?
Increase
Greater
It allows molar uprighting into age 20
Per ABO, there should or should not be a significant difference between heights of buccal and lingual cusps of maxillary and mandibular molars and premolars
should not
Which molars, maxillary or mandibular tend to upright more with age?
the maxillary molars
What are the limits of maxillary expansion?
basicranium
musculature
true or false… you can see some mandibular uprighting with maxillary expansion
true
According to the Moorrees study, inter molar width [increased/decreased] to age 9-14, arch length [increased/decreased] from age 9 to 14 and remained constant after 14, there was a rapid [increase/decrease] in inter canine width from age 6-9 in mandible
increased
decreased
increase
With treatment, ___ and ___ width increased significantly. After treatment ____ decreased and ___ stayed the same.
inter canine and inter molar
inter canine
inter molar
True or false… maxillary inter molar width is NOT related to masseter thickness in males vs females
true
Females showed slight association with weak maxillary inter molar width with masseter thickness. Males’ inter molar width was not related to masseter thickness
Bishara showed that 71.4% of any expansion in lower ___ width resulted in relapse with less relapse seen in upper.
intercanine
Moorrees found that there is a general tendency towards [increase/decrease] in inter molar width in transitional dentition.
increase
True or false.. if a canine is lingually displaced it can be expanded and be stable
true. However, expansion of inter canine width is not stable
Is arch expansion more stable with or without extractions? Is it more stable in the anterior or posterior dentition?
It is most stable without extractions. It is the most stable in the posterior
True or false… molar expansion reduces arch depth (arch length)
true. as posterior width is increased, the spacing in the arch is closed to ensure inter proximal contact
What percentage of pts with distal step present a class 2 molar relationship in permanent dentition?
about 60%
What percentage of pts with mesial step present a class 1 molar relationship in permanent dentition?
about 83%
In regards to the bones of the calvaria, bone is mainly ___ on the ectocranial and endocranial sides, however it is mainly ___ on the endosteal surfaces. This results in….
Depository
resorptive
Thickening and flattening of the bones of the calvaria
Do males or females recover better from the crowding experienced in the mixed dentition?
males
Arch size/alveolar growth increases [slightly/significantly] in the maxilla between ages __-__ after eruption of the ___. This occurs in males or females more/
slightly
8-10
2s
females
Arch size/alveolar growth of the mandible increases [slightly/significantly] between ages __-__ in males and __-___ in females after eruption of the 2s
significantly
8-9
7-8
Therefore, changes in arch dimensions (spacing and crowding) seem to be triggered by the eruption of permanent teeth
In regards to alveolar drift of the maxillary arch, it drifts which direction and by how much?
down and forward 4mm
If a patient is end-end primary molar relationship, ____ and ___ is required in order to obtain class 1 in permanent dentition
leeway space
horizontal mandibular growth
Compare male versus female facial features
male lungs larger (so nose longer?). forehead more protrusive/sloping, male eyes appear more deep set
female nose smaller, straight to concave profile, turned up/bulbous/upright forehead (smaller frontal sinus). female eyes are more bulging. have more prominent and higher appearing cheek bones (upper jaw looks more prominent)
True or false… the pre-pubertal face is very similar for males and females
true. the difference starts at puberty
The ___ relate directly to the alignment and direction of growth of the adjacent nasal region. The plane of nasomaxillary region is approximately perpendicular to the plane of this structure. This is due to increase in size of the brain
olfactory bulbs
The vertical human profile results in what things?
bulbous forehead
rotation of the whole nasal region into an essentially vertical plane
reduction of snout protrusion with medial orbital convergence
rotation of orbits into upright positions
rotation of maxillary complex down and back and during of nasomaxillry complex.
leveling of horizontal palate and maxillary arch
creation of maxillary sinuses
addition of an orbital floor and latearl orbital wall
bimaxillary reduction in the extent of prognathism matching nasal reduction
The mid facial plane is __ to the olfactory bulb, limited in humans by the anterior surface of the ___
perpendicular
anterior surface of the brain (limiting anterior limit of facial development)
The forward boundary of the brain is shared by the forward border of the ____. the course of growth by the nasal part of the face relates to the ___
nasomaxilary complex
olfactory bulbs and sensory olfactory nerves
The posterior plane of the Midface extends from the junction between __ and ___.. this vertical plane passes along the posterior surface of the ___.
anterior and middle cranial fossae
maxillary tuberosity
which is more variable in its anatomic boundaries the maxilla or mandible?
mandible. because it is more distant from the cranium
true or false… the anterior limit of the nasomaxillary complex can be increased by extrinsic forces such as thumb sucking
true. if force is removed, it may rebound to physiologic limit
Facial height is correlated with ___ height and posterior facial height is well correlated to ____
statural height
statuary height growth velocity
which develops first in neuromuscular development of the face, the muscles of mastication or the muscles of facial expression
muscles of facial expression. However, earlier in development the muscles of facial expression are used to stabilize the mandible when swallowing
When is the mature swallow developed?
12-15 months
Describe occlusal homeostasis
occlusal stability sum of several forces acting on teeth (sensory feedback from PDL, TMJ, and other parts of masticatory system)
If you want to move a maxillary molar distally, the maxilla has to move ____ in order for apposition to occur at the ___
downward and forward (away from cranial base)
maxillary tuberosity
Explain how the distal jet or headgear works
It pushes maxillary teeth back into the depository area of the maxillary tuberosity. Pterygoid plates limit the posterior tuberosity extent, therefore the maxilla must grow down and forward for the tuberosity to develop to accommodate the teeth. It does NOT increase the size of the maxilla. a potential negative side-effect of this is palisading molars
what is the multiple assurance concept?
the processes and mechanisms that function to carry out growth are virtually always multifactorial. if one component becomes inoperative, other components usually have the capacity to compensate. Malocclusions are a result of adaption not occurring
as the surrounding bones enlarge or become displaced in many directions and at different rtes and times, the sutural system of the ___ provides for the slippage of multiple bones along sutural interfaces as they enlarge differentially. This permits displacement of the maxilla inferiorly
lacrimal bone
describe the growth of the maxillary tuberosity
lengthens posteriorly by deposition on the posterior-facing maxillary tuberosity
grows laterally by deposits on the buccal sufcae
grows downward by deposition of bone along the alveolar ridge and also on the lateral side.
The endosteal side is resorptive which contributes to maxillary sinus enlargement
What thee things happen in regards to the dentoalveolus that influence tooth position?
dentoalveolar drift (down and forward)
eruption
actual tooth movement within the alveolus
What are some complications involved with vertical drift of alveolus?
ankylosed teeth
implant placement when growth not complete
failure of eruption resulting in resorption of alveolus
The lining surfaces of the bony walls and floor of the nasal chambers are predominantly ___ except for the nasal side of the olfactory fosse
resorptive
this produces a lateral and anterior expansion of the nasal chambers and downward relocation of the palate (the oral side of palate is depository)
In regards to growth/development of the nasal airway, the ethmoidal concha move in which direction(s)?
downward and laterally
True or false… the inferior inter orbital area increases with increase of width of nasal cavity
true
True or false… the width of the nasal bridge greatly increases from childhood to adulthood
false
In regards to palatal remodeling, the labial side of the anterior part of the maxillary arch is ___ with bone being [added/removed] to the [inside/outside] of the arch. the arch increases in width and the palate becomes wider following the V principle
resorptive
added
inside
A maximum of ___mm of crowding in the mandibular arch can be treated by arch development
4mm
(close to amount of leeway space
The [inferior/superior] edge of the zygoma is heavily depository
The malar region and anterior part of the zygoma undergo [anterior/posterior] remodeling movement
inferior
posterior (as it is displaced anteriorly and inferiorly)
The growth changes of the malar process are similar to those of the mandibular coronoid process, its counterpart
does the face relocate from under the cranium in a clockwise or counterclockwise rotation?
clockwise
The orbit expands and moves in a downward and forward direction. the nasal floor in an adult is much ___ than the orbit in a child
lower
In the orbit, deposition takes place on the ___ side of the orbital floor and resorption occurs on the ___ side.
superior
inferior
During growth of the mandible, the ramus is uprighted by remodeling in what direction relative to the body of the mandible?
upward and forward
True or false… with growth, the ramus becoming increasingly wide in the A/P dimension.
false
how does the chin form?
uprighting and resorption at infra-incisor area
bone deposition on chin
According to study done by ingervall, the condylar inclination [increased/decreased] with age
increased
Due to continuous growth in height of articular eminence
Forward rotation of the mandible occurs in what three different ways?
type 1 - forward rotation w/ centers in joints pushing mandible up.
type 2 - forward rotation w/ center at incisal edges
type 3 - in cases of great max or mand oj, center of rotation moves to premolars
which occurs more frequently, forward or backward rotation of the mandible?
forward
What are some structural signs of extreme growth rotation of the mandible?
inclination of condylar head curvature of mandibular canal shape of lower border of mandible inclination of symphysis interincisal angle interpremolar/molar angle anterior lower face height
Do deep bite patents exhibit backward or forward rotation of the condylar head?
forward
true or false… growth rotation of the mandible affects tooth eruption path
true
