The Face and Oral Embryology Flashcards
What are the regions of the face
- 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
The lips
-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.
oral cavity https://quizlet.com/417684262/chapter-10-oral-cavity-flash-cards/
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.
- 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.
Gingival tissue
Gingivae: gums are masticatory mucosae cover alveolar processes of jaws and surround the necks of teeth
What are the characteristics of a normal gingivae.
- surround the tooth in collar like fashion and self cleansing.
- they are firm and resistant and tightly adapted to tooth and bone.
- 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.
- surface color varies according to indvidual’s pigmention.
- gingival groove is a shallow groove that run parallel to the margin of unattached gingiva and marks the begining of the attached gingiva.
- attached gingiva extends from the base of the sucus to the mucogingival junction.
unattached gingiva
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.
The hard palate
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.
soft palate
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
The Gag reflex
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.
tongue function
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.
Embryology and histology
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.
prenatal development
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
tooth develpment
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
tooth development disturbances
- 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.
what are issues that can occur during development of teeth
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.
prenatal fevelopment
- 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.
life cycle of a tooth
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.
Anatomy of tooth
- 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.
Anatomy of tooth
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.
tooth fissures
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.
periodontium:
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
oral mucosa
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
Dentition
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
Tooth development stages
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
