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What is the difference between hyperplasia, hyperplastic and accretion?
Hyperplasia: ↑ in the number of cells→gingival hyperplasia seen in Dilatin therapy.

Hypertrophy: ↑ in the size of cells

Accreation: ↑ in the amount of non-cellular material (Hurler's Syndrome, mucopolysaccharidosis)
What is the embryonic period?
The first 8 weeks after fertilization and implantation.
What are the 3 components of the brachial/ pharyngeal apparatus?
1. Bracial Arches (4)
2. Brachial Pouches (inner surface)
3. Brachial Grooves (cleft-outer surface)
1st Brachial Arch: Mandibular arch

2nd Brachial Atch: Hyoid Arch

3rd Brachial Arch: Glossoopharybgeal

4th Brachila Arch: Plus
Which Brachial/Pharyngeal arch is a major contributor of facial features?
1st, Mandibular arch.
Name the cartilage, muscle and nerve associated with each arch.
Mandibular arch:
- Meckel's cartilage
- muscles of mastication, tensor palatini, mylohyoid, tensor tympani, ant. digastric
- Trigeminal nerve (V2, V3)

Hyoid Arch:
- Reichart's cartilage
- Mus. of facial expression, post. digastric, stapedius, stylohyoid
- Facial nerve (VII)

Glossopharyngeal:
- Greater Cornu cartilage
- stylopharyngeus mus.
- glossopharyngeal nerve (IX)

Plus 4th Arch:
- thryoid cartilage
- laryyngeal mus. pharyngeal constrictors
- vagus nerve (X)
Mergence vs. Fusion
Structures in the midline MERGE.
Structures located laterally FUSE → more anomalies than mergence.
Facial Processes: 5 prominences surround primitive mouth.

1. Single medial frontonasal (1): Lateral nasal processes & median nasal processes→primary palate

2. Paired maxillary processes→secondary palate.
3. Paired mandibular processes.
When are facial structures "defined" during in utero development?
During the embryonic period; 3-11 wks
What are 3 syndromes/pathologies associated with anomalies of the 1st brachial arch?
1. Pierre Robin Sequence
2. Treacher Collins Syndrome (mandibulofacial dysplasia)
3. Hemifacial microsomia
4. Cleft lip/palate
9 weeks in utero to birth is known as which period?
Fetal period
MN Process→Primary palate "zips" closed from posterior to anterior. Incisors arise in primary palate.

Max. Process→Palatal shelves→Seconday palate "zips" closed from anterior to posterior.

Clefting can occur anywhere along these paths.

Mildest form of cleft palate is cleft uvula (failure of fusion of the secondary palate).
When is palatal fusion complete?
11 weeks in utero.
Closure is oriented at the incisive foramen and closes anteriorly (primary palate) and posteriorly (secondary palate) from there.
Why may a cleft uvula be clinically important?
Submucosal cleft palatal bones fail to fuse but soft tissue is closed. (triad)
1. Bifid uvula
2. palatal muscle diastasis
3. notch in posterior of hared palate.

Prone to ear infections (cleft prevents movement of tensor palatini which closes auditory meatus.

hypernasal speech
TRUE?FALSE: Cleft palate is more common in females due to later closing of secondary palate.
TRUE
What are some dental anomalies associated with clefting?
SN teeth (distal to lateral incisors)
missing teeth (laterals)
enamel defects 
↑ caries rate
Pierre Robin Sequence

1. Glossoptosis
2. Mandibular retrognathia/micrognathia
3. Cleft Palate.
Cleft lip most commonly results from the failure of fusion of which two structures?
Median nasal process with the maxillary process.
TRUE/FALSE: Cleft lip is more common in males.
TRUE 2:1
Left side most common
NAM Appliance
Neonatal pre surgical technique used to mold soft tissue, alevolar bone and palate into favorable growth pattern. Approximates cleft segements closer together.

Also acts as a obturator. Adjustments are made weekly as child grows.
What are the stages of CL/P repair?
1. Neonatal treatment
- obturator, tissue molding ~ 5weeks
- lip adhesion
- surgical lip repair ~ 5 months
- palate repair ~10 months

2. Orthodontic/orthopedic treatment in mixed dentition
- max. expansion & bone grafting to be done while permanent canines are completetly in bone.

3. Comprehensive ortho tx.

4. Orthognathic surgery/distraction osteogenesis.
Latham appliance
Used in the mangement of cleftj palate/lip.
FIxed, secured with pins, activated daily to bring cleft segments together to make surgery easier.
What are the different types of bone formation? Differentiate.
Endochondral bone formation (EBF): cartilage precursor
- generally occurs in areas of pressure.
- i.e long bones (pressure of kids walking around along with gravity stimulates chrondoblasts→cartilage→bone.
- cranial base
- Disorder of EBF: Achondroplasia (dwarfism), midface hypoplasia

Intramembranous bone formation (IBF): No cartilage precursor
- generally forms in areas of tension. 
- skull sutures (expansion of the brain creates tension on the sutures which stimulates bone formation.
- Disorder of IMF: Cleidocranial Dysplasia
What direction does maxillary growth occur?
Downward and forward via displacement

IBF
What occurs when the sutures fuse prematurely and do not allow for intramembranous ossification?
Craniosynostosis.
What are 2 syndromes associated with craniosynostosis?
1. Apert's Syndrome.
2. Crouzon's Syndrome.
Apert's Syndrome

Congenital
1st Brachial arch anomaly
S/S: Craniofacial malformations, Syndactyly
Cognitive deficiency
Crouzon's Syndrome

Congenital 1st brachial arch anomaly
Normal intelligence.
Growth Site vs. Growth Center
Growth centers initiate growth; growth sites do not.

Condyles are growth site.
TRUE/FALSE: Most mandibular growth occurs via intramembranous growth formation
TRUE, however there are areas of endochondral bone formation.

**Mandibular growth occurs posterior to the second primary molar.**
SNA:horizontal position of the maxilla relative to the  cranial base 82°

SNB: horizontal position of the mandibule relativ to the cranial base 80° 

ANB: relative position of the maxilla to the mandible 2°
Down's Analysis reference plane:
Franfort's Horizontal plane→ Porion (Po) to Orbitale (Or)
-parallels horizontal edge of film
Verticle dimension is the Facial Plane/Angle: Nasion to Pogonion.
- parallels veritcle edge of film
- FH-FA=90°

Steiner Analysis reference plane: Sella-Nasion
- used to measure maxilla and mandible to cranial base.
A line extending from the mandibular plane should fall along the base of the occiput.

If the line extends well into to skull→HYPERDIVERGENT; skeletal open bite tendency; ↑VDO dolichocephalic; favors extraction therapy; encourage posterior intrusion

If the line falls outside of the skull as seen here→HYPODIVERGENT; Skeletal deep bite; bradycephalic; non-extraction therapy; encourage posterior extrusion.
Distal step in the primary dentition results in which malocclusion in the permanent dentition?
Class II
Flush terminal plane and mesial step occlusion in the primary dentition usually results in....
Class I Malocclusion
Cervical Pull:
- extrudes and distalizes maxillary molars.
- encourages counter clockwise rotational growth of mandible→closes ant. open bites; opens post.
- may tx normal or hypodivergent, brady profiles.

High Pull:
- intrudes max. molars while keeping their M-D position.
- encourages clockwise mand. growth→ closes post. opens ant.
- may tx hyperdivergent profiles, doli profiles.
Reverse pull headgear:
- Tx: Class III
- protracts maxilla
- mesial movement of max. molars and incisors
- opens bite
- allow for lingual uprighting of lower incisors
Define the Early Mesial Shift
Closure of generalized posterior spacing with the eruption of the 1st permanent molars.

Define the Late Mesial Shift
Mesial drift of permanent 1st molars into leeway/E space.

Note: The primary 1st molar and the 1st PM are the same size. Whereas the primary second molar is much bigger than the 2nd PM, hence the term "E" space.
At what age is mand. arch length the greatest?
Age 4

Generalized arch spacing still present.
No early or late mesial shifts.
Arch length ↓'s on which 2 occasions?
Early mesial shift→eruption of permanent 1st molars

Late mesial shift→loss of 2nd primary molar
A: Flush = Class 1 > Class 2
B: Distal Step = Class 2
C: Mesial Step = Class 1 > Class 2

Excessive Mesial Step = Class 1> Class 3
Primate Spaces
Max: Mesial to canine
Mand: Distal to canine
TRUE/FALSE: Crowding in primary dentition ALWAYS results in crowding in the permanent dentition.
TRUE.

No spacing in primary dentition→66% chance of crowding in permanent dentition

Spacing ≥6mm in primary dentition = no crowding in permanent dentition
TRUE/FALSE: The size of primary teeth are good predictors of the size of permanent teeth.
FALSE.
What are the ideal measurements/occlusion in the primary dentition?
Mesial step (molar and canine)
Generalized and primate spacing
2mm OJ
2mm (30%) OB
What is the leeway/E space in each arch?
Mandible 1.7mm
Maxilla 0.9mm
Summarize arch dimension changes:
Intercanine width
Intermolar width
Arch length
Intercanine width:

Maxilla ↑

Mandible ↑
With the eruption of the permanent canines due to their more labial positions.

Intermolar width:

Maxilla ↑

Mandible ↓ Due to mesial shift

Arch length:

Maxilla ↑ slightly due to labial position of incisors and increased intercanine width

Mandible slight ↑ in anterior archlength due to labial position of incisors and increased intercanine width; ↓ posterior arch lenght due to late mesial shift
Which two medications have a profound effect on orthodontic tooth movement?
Anti-inflammatory meds→removes inflammation necessary for tooth movement
Bisphosphonates→decreases action of osteoclasts


Name the muscles of mastication and their actions.
1. Masseter: Elevates mandible; protrudes; retrudes
2. Medial Pterygoid: Elevates; excursive movements; protrudes
3. Lateral Pterygoid: DEPRESSES Mandible; excursive movements; protrudes
4. Temporalis: Elevates; retrudes; excursive
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