Growth of maxilla

Nasal placodes invaginate to form nasal pits at what week?

5th week

Two prominences surrounding the nasal pits

Lateral nasal prominence (outer edge), medial nasal prominence (inner edge)

Which prominence does NOT contribute to the upper lip

Lateral nasal prominence

What forms the upper lip

Fusion of the two medial nasal prominences with the maxillary prominences

What forms the lower lip and jaw

Mandibular prominences merging across the midline

Five facial prominences that form the nose

Frontal prominence (bridge), 2 medial nasal prominences (crest/tip), 2 lateral nasal prominences (alae)

Intermaxillary segment - three components

Labial component (philtrum), upper jaw component (4 incisors), palatal component (primary palate)

What is the intermaxillary segment continuous with

Rostral portion of the nasal septum (from frontal prominence)

Week the palatine shelves first appear

6th week

Stage 1 of secondary palate fusion

Lateral differentiation of palatine shelves, directed obliquely downward beside tongue

Stage 2 of secondary palate fusion

7th week - tongue moves downward, shelves ascend to horizontal position

Stage 3 of secondary palate fusion

Lateral growth of the shelves

Stage 4 of secondary palate fusion

Creation of epithelial wall

Stage 5 of secondary palate fusion

Fusion of shelves ~1/3 of the way back, proceeds anterior to posterior

Landmark between primary and secondary palate

Incisive foramen

Week of intramembranous ossification of the palate

8th week I.U.

Ossification centers for the fused lateral palatal shelves

Trabeculae from primary ossification centers of each palatine bone

Where does ossification NOT occur in the palate

Most posterior part - becomes the soft palate

Branchial arches supplying soft palate musculature

First, second, and fourth arches

Week the midpalatal sutural structure becomes evident

10.5 weeks

Fetal palate growth pattern 7-18 weeks

Length increases faster than width

Fetal palate growth pattern after 18 weeks

Width increases faster than length (midpalatal suture + appositional growth)

Least severe form of cleft palate

Bifid uvula

Maxilla body - what cavity does it contain

Maxillary sinus (antrum of Highmore)

Four surfaces of the body of the maxilla

Anterior, posterior/infratemporal, superior/orbital, medial/nasal

Four processes of the maxilla

Zygomatic, frontal, alveolar, palatine

Shape and description of the palatine bones

Irregularly shaped, L-shaped bones

What do the palatine bones form

Posterior hard palate, lateral wall of nasal fossa (between medial pterygoid plate and maxilla), posterior floor of orbit

What separates nasal cavity from oral cavity posteriorly

Horizontal plates of the palatine bones

Three postnatal growth directions of the maxilla

Vertical, horizontal, transversal

Two mechanisms producing vertical (downward) growth of maxilla

Sutural displacement of the whole nasomaxillary complex, and remodeling (resorption/deposition)

Proportion of downward maxillary arch movement from sutural displacement

About half

Bone surface pattern in vertical maxillary growth

Deposition on downward-facing surfaces, resorption on superior-facing surfaces

Two-part process of downward tooth movement

a to b: remodeling of alveolar bone (paced by periodontal membrane); b to c: displacement of maxilla as a whole (alveolar bone not participating)

Principal site of horizontal maxillary elongation

Maxillary tuberosity

Until what age does anterior bone deposition contribute to horizontal maxillary growth

5-6 years

What does posterior bone deposition at the tuberosity cause

Anterior displacement of the maxillary complex

Relationship between forward displacement and backward tuberosity growth

Extent of forward displacement is matched by amount of backward bone growth

What allows transversal (width) growth of the maxilla

Presence of the mid-palatal suture (open throughout growth)

Second contributor to maxillary width besides the suture

Remodeling of the palatal vault (resorption on nasal side, apposition on oral side)

Who studied maxillary growth using metallic implants

Bjork and Skieller

Maxillary width increase (bi-molar) from Bjork/Skieller implant study

+9.5 mm sutural component / total change measured across the arch

Growth site vs growth center - definition

Site = location where growth occurs; center = location of independent, genetically controlled growth

Are maxillary sutures growth centers or growth sites

Growth sites, NOT growth centers

What do maxillary sutures allow

Downward and forward positioning of the maxilla

"Push" theory of maxillary displacement - accepted or rejected

Rejected

"Sutural" theory of maxillary displacement - accepted or rejected

Rejected

Nasal septum theory of maxillary displacement - proposed by

Scott

Is there cartilage in the maxilla itself

No

Where is the cartilage that influences maxillary growth

Nasal septum

Type of ossification at the septo-ethmoidal junction

Endochondral ossification

Where is proliferation seen in septal cartilage

Vomeral edge of the cartilage

Bone activity pattern in the palatal area (nasal septum theory)

Resorption on nasal side, apposition on oral side of bony palate

Who proposed the Functional Matrix Theory

Melvin Moss

Core claim of Functional Matrix Theory

The bone does not regulate its own growth rate/direction; functional soft tissues are the actual governing determinant

What does Functional Matrix Theory explain vs not explain

Explains WHAT happens, not HOW it happens

Term for the functioning spaces around the maxilla/mandible per Moss

Orofacial capsular matrix

Per Moss, what enlarges to drive maxillary growth

Nasal and oral cavities (e.g., maxillary sinuses) in response to functional needs

Overall consensus on the driving mechanism of maxillary growth

Multifactorial process

Who conducted the Bolton-Brush Longitudinal Study on adult craniofacial growth

Behrents

Does craniofacial growth stop after adolescence

No - continues into adulthood

Three clinical fields a