The Face and Oral Embryology

Question 1

What are the regions of the face

Answer 1

• forehead: extending from eyebrows to hairline
• temples: anterior to eyes
  -orbital: eye area that is overed by eyelide
  -external nose
  -zygomatic: cheek
  -mouth and lips
  -chin
  -external ear

Question 2

The lips

Answer 2

-known as labia
-lip are outline by vermilion border.
- labia commissure is angle at corner of mouth
-nasolabial sulcus is groove extending upward between each labial commissure and ala of nose.

Question 3

oral cavity https://quizlet.com/417684262/chapter-10-oral-cavity-flash-cards/

Answer 3

is a lined with mucous membrane tissue.

The oral cavity consists of two areas:
1. vestibule: the space between teeth and inner mucosal lining of the lips and cheeks.

2. oral cavity proper: the space contained within the upper and lower dental arches.

-frenum: is a narrow band of tissue that connects two structures together.

• buccal frenum: passes from the oral mucosa near the maxillary first molars to the inner surface of the cheek.

-intraoral vestibular: begins inside of lip and includes the mucogingival junction, buccal vestibule, parotid papilla, and linea alba.

Question 4

Gingival tissue

Answer 4

Gingivae: gums are masticatory mucosae cover alveolar processes of jaws and surround the necks of teeth

Question 5

What are the characteristics of a normal gingivae.

Answer 5

1. surround the tooth in collar like fashion and self cleansing.
2. they are firm and resistant and tightly adapted to tooth and bone.
3. the surface of attached gingivea and interdental papillae are stripped and similar in appearance to rind of an orange. the interdental gingiva known as gingival papilla.
4. surface color varies according to indvidual’s pigmention.
5. gingival groove is a shallow groove that run parallel to the margin of unattached gingiva and marks the begining of the attached gingiva.
6. attached gingiva extends from the base of the sucus to the mucogingival junction.

Question 6

unattached gingiva

Answer 6

known as marginal gingiva or free gingiva, is the border of the gingiva surround the teeth in collar-like fashion.

the unattached gingiva usually about 1 mm wide and form the soft wall of the gingiva sulcus.

The teeth sit in bony sockets, or alveoli , within alveolar process of maxilla and mandible.

In the mouth, a cuff of gingival tissue surrounds each tooth. the portion of the tooth is visible in the oral cavity is called the crown.

Question 7

The hard palate

Answer 7

separates nasal cavity above from the oral cavity below.

hard palate composed of

-incisive papilla: a pear shaped pad of tissue that covers the incisive foramen

• palatal rugae: are irregular ridges of masticatory mucosa, lateral from incisive pailla.
• palatine raphe: posteriorly from insisive papilla at midline.

Question 8

soft palate

Answer 8

moveable posterior third palate

characteristics:
1. it has no bony skeleton
2. it ends posteriorly as free edge with hanging projection called uvula.
3.it is supported posteriortly by two arches , the fauces

Question 9

The Gag reflex

Answer 9

is a protective mechamism that occure in the posterior region of the mouth. very sensitive area includes the soft palate, fauces, posterior potion of the tongu.

Question 10

tongue function

Answer 10

speech
manpulation and positioing food
sense of taste
swakkowing
cheansing oral cavity

parts of surface of tongue
-body: anterior two thirds of tongue
-Root: posterior portion that travels toward the pharynx
-Dorsum: upper and posterior roughened surface.

Question 11

Embryology and histology

Answer 11

Embryology: study of prenatal deveoplment in stages before brith. learing about th oral cavity is the fundation for understanding developmental problem that can occure in these structures.

histology: study if streucure and function of tissue on microscopic level. oral mucosa which suround s the teeth and lines the mouth. By undersatnding the histology of oral tissues the dental assisentane can understand the disease processes that occur in the oral cavity.

Question 12

prenatal development

Answer 12

the embryonic period beginning oof second week end of 8 week.
during 2 week develpmentmt, cells of embryo form 3 primary embryonic layers
- ectoderm
- mesoderm
- endiderm

5 stage, palate start to develop, at this stage
there two separated embryonic structures
-primary
-secondary

6,7 secondary palate will grow toward the primary palate and fuse to complete hard palate

Question 13

tooth develpment

Answer 13

the earlies signs of tooth development are found in anterior manduular regin when embryo is 5 to 6 week old. By 17 week, develpment of permanent teeth has begun.

At birth, there aare normally 44 teeth in various stages of developemnt.

enamel formation is well underway on all primary dentition and beginnings of the permanent first molars

Question 14

tooth development disturbances

Answer 14

• fever in the mother during pregnancy will leave marks in the developing teeth of fetus.
• when pregnant women take the systemic anitbiotic terracyline during fetal peeriod,permanent staining of the child’s primary teeth might result.
• toxins from a dental infection can be dangerous to both mother and child. for example, toxins. from periodontal disease in mmother are linked to low birthweight in infant.

Question 15

what are issues that can occur during development of teeth

Answer 15

Cusps, pits, and fissures

• Cusps: A cusp is pointed or rounded mound on the crown of the teeth.
• fissure: is a fault along a develpmental groove on the occlusal surface caused by incomplete or imperfect joing of the lobes during the formation of the tooth.
• pit: results when two develpment grooves cross each other, forming a deep area that is too small for bristle of a toothbrush to clean.

Question 16

prenatal fevelopment

Answer 16

• osteoblasts: a cells responsible for new born bone formation (deposition).
• osteoclasts: cells responsible for removing bone (resorption)
• osteocytes: cells maintain bone. osteocytes are osteoblasts or osteoclasts that are buried by osteoblasts when new bone is laid down.

Remodeling: process by which bone is removed and replaced. bone is constanyly remodeled.

Question 17

life cycle of a tooth

Answer 17

Odontogenesis: a process of tooth formation. process divided into three primary periods

• growth
  -calacification
• eurption

active eruption of primary tooth involves many stages of movement of tooth.

the process of eruption for a permanent tooth is same as that for primary tooth. when a permanent tooth starts to erupt before the primary tooth is fully shed, problems in spacing can arise.

• Bud stage: initiation, formation of tooth begins.
• cap stage: proliferation, cells of developing tooth increase.
• bell stage: histodifferenition l different tissues of tooth form and its shape are established.
• calacification: process by which structural uline of tooth formed during growth stage stage and hardened by deposit of calcium other mineral.
• Erption: movment of tooth into its functional position in oral cavity. it impotant that dental assistants know the eruption schedule of the primary and secondary teeth.
• Exforliation: normal pocess by which the primary teeth are lost. when it is time for primary tooth to be lose, osteoclast cause the resortion of the root, begining at apex and continuing in the direction of the crown. eventually, the crown of the tooth is lost because f lack of support.

Question 18

Anatomy of tooth

Answer 18

• Anatomic crown: is portion of tooth that covered with enamel.
• clinical crown: portion of rhe tooth hat is visible in the mouth.
• Root: potion normally embedded in the alveolar process; it is covered with cementum. dependng on type of tooth, root can a have one , two (bifurcated) or three (trifurcated) root.
• Apex: tapered end of each-root tip. anyting that situated at apex is apical. anything surrounding the apex is perioical.

Question 19

Anatomy of tooth

Answer 19

each tooth consists of crown and one or more roots.

-The crown dentin covered by enamel
-each root has dentin covered by cementum
-inner potion of dentin of both the crown and root covers the pulp cavity of tooth.

enamel is translucent means some light passed throught it and ranges in clor frim yelow to grayish white.

cementum on tooth is quickly abraded, leaving exposed dentin. Cementum on rooth is light yellow and easilt distinguishable from enamel by its lack of luster and its darker hue. lighter in color than dentin.

Question 20

tooth fissures

Answer 20

Enamel: make up anatomic crown of tooth and is the hardest material of the tooth body.

Dentin: makes up main portion of tooth structure, which exteneds almost the entire length of tooth. it is covered by enamel on the crown and by cementum on the root, dentin is primary, secondary, tertiary ( reparative dentin).

• cementum: covers roots of tooth,it overlies dentin and joins the enamel at cemenel juction. primary function is to anchor the tooth to bony socket with attachment of fibers

pulp: made uo of blood vessels and nerves that enter the pupl chamber through the apical formen.

Question 21

periodontium:

Answer 21

supports teeth in alveolar bone. Also protect and nourished teeth by way of blood vessels and immune response.

two major unites periodontium
- attachment apparatus
-gingival unit

comprised of
-cementum
-alveolar bobe
-periodontium ligaments
-alveolar crest fibers

Question 22

oral mucosa

Answer 22

composed stratified squamous epithelium connective tissue. oral mucosa almost continuously lines the oral cavity.

-lining: covers inside cheecks ,lips, soft palate and underside of tongus.

• masticatory: upper side of tongue and attached gingiva.
  specialized:helps form the taste papillae

Question 23

Dentition

Answer 23

development of teeth and their arragment in mouth.

-primary Dentition: frist 20 primary teeth.

-mixed Dentition: occurs between 6-12y. both primary and permanent teeth are present

permanent Dentition: adult set of teeth

Question 24

Tooth development stages

Answer 24

tooth development or odontogenesis (adult set 32 teeth.
- tooth development begins around 5-6 week in embryonic stage. by 7th week, primary has developed as well some of permanent. by birth 44 teeth will develped

Question 25

tooth develpment 7 stages

Answer 25

stage 1: Initiation: tooth bud forms. bun stages. A membrane surrounding a small growth of epithelia tissue known as dental lamina leads to tooth bud.

stage 2 proliferation: tooth buds grown to form 20 primary teeth. 4th to 5th of pregancy, small tooth buds begins to grow and develop 20 primary teeth knows as proliferation

stage 3 Differentiation: tooth goes throght morohodifferentiation (tooth bud begibs to take on diffrent shape more bell like.

and histodiffebtion: tissue make up also begins to change. tooth bud into pats eamel,papilla,follicle

Differentiation is process of physical change in cell function as a cell develops and matures.
two main differentiion:
1. enamel organ: composed of ameloblast that produce
2.dental papilla: compsed of adontoblasts that produce dentin makes up bulk of tooth.

dental follicle sac covers tooth bud in this stage. it contains cementoblasts for tooth root.osteoblasts produce bone and fibroblasts produce fibers

stage 4 apposition: the tooth crown forms and begins to harden. known as a crown stage. the crown on tooth will take shape and hard tissues will start to form. the overall size of bud has finished growing by apposition stage so tooth begins to harden. by the end of oppositional stage enamel has completely mineralized.

Question 25

Stage 5, 6

Answer 25

stage 5 calcifation : tooth forms enamel, detin, cementum and periodontium
prior enamel hardening, dentingenesis creation of dentin occurs. it is frist characterustic to be seen in crown stage.
near end of tooth’development cementogensis occurs. periodontium is supporting tissue of tooth composed of periodontal ligments,alveolar bone,gingiva ,cementum

stage 6 Eruption: tooth breaks thorught gingiva to grow into place in the mouth. 3 stages if eruption
- primary dentition stage : only primary teeth are visble.
- mixed dentition stage: some primary tetth lost (exfoliation) and peranent tooth erups both primary and permanet in mouth.
- permant dentition stage: only permaned teeth are visible.

Question 26

stage 7 attrition

Answer 26

occlusal surface of teeth can be worn down.

Question 27

abnormalities during tooth developmnt

Answer 27

• Amelogenesis imperdecta: due to infection, birth injury or trauma enamel does not form completely.
• Dens in dente: early in enmael formation “fold” in enamel
• Dentingenesis imperfecta: dentin discolored giving tooth gray to browish

-Flourisis: teeth present yellowish with white spots

-fusion: two teeth into one tooth during bud stage of development.

• Anodontia: complete lack of tooth development genetic disorder.

Question 28

other abnormalities

Answer 28

• gemination: one tooth separates to form two crown on a single tooth.
• macrodontia: large teeth
• microdontia: small teeth (one or two)
  -supernumerary teeth: extra teeth might or might not be erupted

Question 29

hard tissues

Answer 29

teeth types:
-incisores, permolarmolars, molars. has same tissue structures and same anatomic and structural landmarks.