Exam 2 Flashcards
What is HERS?
At the base of the tooth crown, the confluence of the inner and outer enamel epithelium elongate to form a bilayered Hertwig’s epithelial root sheath. It is an extension formed by the free edge of the enamel organ on the developing tooth which goes beyond the DEJ and molds the dental papilla to form the root of the tooth. It also initiates formation of dentin in the root of a tooth by causing the differentiation of odontoblasts from the mesenchyme of the dental papilla.
What is given to babies with cleft lip or palate to help them eat?
Obturator
What has cleft lip been attributed to?
Underdevelopment of the mesenchyme of the maxillary swelling, which results in inadequate contact of the maxillary swelling with the intermaxillary process.
What happens during inductive stage of amelogenesis?
Dentin is not mineralized, and the IEE has a cuboidal or low columnar appearance, with centralized nuclei and poorly developed Golgi. The IEE cells then elongate and become preameloblasts, but no Tomes process yet. It is at this stage that the ameloblasts send a signal across the DEJ to stimulate dentinogenesis.
From what three pairs of cartilaginous precursors does the chondocranium develop from?
- Ethmoid prechordal cartilage 2. Sphenoid hypophyseal cartilage 3. Occipital parachordal cartilage
What innervates the taste component of the anterior 2/3 of the tongue?
It is supplied by the chorda tympani branch of CN VII-facial nerve, which innervates all taste buds except the circumvallate papillae.
What kind of heart defects can accompany DiGeorge syndrome?
Because of lack of blood, you can get a ventricular septal defect, only one large vessels instead of two (truncus arteriosus), or four abnormal heart structures (tetralogy of Fallot)
What is minor clefting?
Involves only the soft tissue of the lip and results in a notch in the vermillion border of the lip just lateral to the philtrum called a partial cleft.
What is the oronasal membrane?
It separates the nasal sac from the oral cavity, similar to the nasal fin, but forms when vacuoles develop in the nasal fin, fuse with the nasal sac, enlarging it and thinning the fin to a thin membrane called the oronasal membrane.
Dentinogenesis takes place throughout our entire lives. True or False?
True. Secondary dentin production happens.
What ends up forming the anterior two thirds of the tongue?
Distal tongue buds
Artificial saliva can also help stimulate salivary gland production. True or False?
False. Just helps lubricate and replace moisture lost.
What are the three kinds of amelogenesis imperfecta?
- Hypoplastic - defect in amount of enamel (pitted). Pitted-Has normal thickness, pitted surface, normal hardness. Generalized-reduced thickness, smooth surface, normal hardness 2. Hypomaturation - defect in final growth and maturation of enamel crystallities and hypomineralization. Has normal thickness, chipped surface, less hardness, opaque white coloration. 3. Hypocalcified - defect in initial crystallite formation followed by defective growth and hypomineralization. Has normal thickness, smooth surface, less hardness.
What do the maxillary swellings do during the fifth week?
They enlarge and grow ventrally and medially simultaneously.
What is the name of the midline swelling that the third and fourth pharyngeal arches give rise to that overgrows the copula on the tongue?
Hypopharyngeal eminence
What is the name of the area between the epiphysis and diaphysis that is made up of uncalcified cartilage?
Epiphyseal plate (growth plate). This is the major center for growth in long bones. While periosteum plays a role in adding thickness and reshapes external contours.
What are the main four drugs that influence neural crest cell migration?
- Alcohol 2. Thalidomide 3. Accutane 4. Retinoic acid
What does sagittal synostosis result in?
Bitemporal narrowing and prominence in frontal and occipital.
What is another name for the small areas of cartilage that represent the old chondocranium?
Synchondroses
What is distraction osteogenesis?
A technique that uses a device to pull the midface slowly forward after surgery and move it further forward than a single surgery can.
What is the name of the muscle that attaches to the posterior aspect of the maxillary palatal shelves?
Superior pharyngeal constrictor muscle, every time we swallow this muscle pulls on the separated palatal shelves. The orbicularis oris muscle is also involved.
What ends up forming the posterior one third of the tongue?
Hypopharyngeal eminence
What are other causes of enamel defects?
Vitamin A deficiency, measles, antibiotics, fluorosis
What are the five principle stages in craniofacial development?
- Germ layer formation 2. Neural tube formation and initial formation of the oropharynx 3. Origin, migration, and interactions of cell population, especially neural crest cells 4. Formation of organ systems, especially the pharyngeal arches and the primary palate and secondary palates 5. Final differentiation of tissues
What causes a facial cleft?
Complete or partial failure of fusion between any of the five facial swellings. Can be unilateral or bilateral.
What are the five facial swellings that all originate from the first pharyngeal arch?
- unpaired frontonasal process 2. Two maxillary swellings 3. Two mandibular swellings
What changes with growth with mineralized tissues?
Hyperplasia, hypertrophy, and secretion of extracellular material can only occur on the surface, not within the mineralized mass. Direct addition of new bone occurs through the activity of cells in the periosteum, and is called direct or surface apposition of bone.
What does cephalocaudal gradient of growth mean?
It means that there is an axis of increased growth extending from the head toward the feet.
By what type of ossification do the maxilla, zyogmatic, and temporal bones form?
Intramembranous ossification
What forms the intermaxillary process?
By the end of week 7, the inferior tips of the medial nasal processes expand laterally and inferiorly and fuse to form the intermaxillary process.
What is a common side effect cleft palates?
Buildup behind the eardrum, which affects hearing.
PTH has no direct established activity on the intestine. True or False?
True, but indiretly it increases intestinal calcium and phosphorus absorption via stimulation of 1,25 dihydroxyvitamin D production.
What are the four main functions of saliva?
- Buffering ability 2. Provides a cleansing effect 3. Has antibacterial action 4. Maintenance of oral environment
What are the two types of cementum? Characteristics? Which one forms first?
- Cellular 2. Acellular -Acellular forms first as cementoblasts differentiate from the dental follicular cells, which only reach surface of tooth once HERS is gone. -Cellular cementum develops after most of tooth formation is complete, it forms around fiber bundles of the PDL, and their cementoblasts become trapped in the cementum they produce.
Amelogenesis takes place throughout our entire lives. True or False?
False. it only happens once, and ends once the ameloblasts are lost within eruption within the REE.
What does the tongue develop from?
From endodermal covered swellings on the floor of the pharynx.
What is ectodermal dysplasia?
Inherited disorders that affect the hair, nails, sweat glands, teeth. You need two of these to be considered. It is genetic, but you can be first in family due to a mutation. Teeth can be missing, pointed, widely spaced, prone to cavities because of defective enamel, multiple denture replacements are needed as child grows, implants may be an option as well, and ortho.
What does PTH do to the kidney and what does it act on?
PTH stimulates the 1-alpha hydroxylase activity in the kidney, resulting in an increase in 1,25 dihydroxyvitamin D production. It also increases the reabsorption of calcium in the distal renal tubules. It also decreases the reabsorption of phosphorus in the proximal renal tubules.
What is the definition of development?
An increasing degree of organization, complexity, or specialization.
What is the primitive choana?
It is formed when the oronasal membrane ruptures during the seventh week to form an opening called the primitive choana.
What forms the nasal fin?
The floor and posterior wall of the nasal sac proliferate to form a thickened, plate like fin of ectoderm separating the nasal sac from the oral cavity called the nasal fin.
What helps form the bony hard palate?
Mesenchymal condensations in the ventral portion of the secondary palate form the bony hard palate.
What does Vitamin D do with calcium?
It helps the intestines absorb calcium, but vitamin D must first be activated by PTH. Vitamin D also increases re-absorption of urinary calcium and phosphorus in the renal tubules. And Vitamin D has a direct effect on the parathyroid gland to suppress PTH secretion when we have too much of it.
What is a LeFort III fracture?
It passes through the nasal bridge medially, extending laterally through the medial orbital rim, nasolcarimal groove, ehtmoid bones, floor of orbit, lateral orbital wall, and zygomatic arch. They separate the entire midface from the cranium, and results in a bone fragment that includes the nasal complex, inferior half of orbit, zygoma, entire maxilla.
The maxilla grows more and later than the mandible. True or False?
False. Just think that the maxilla is closer to the brain, which also grows slower.
What is the bony cap on each end of a long bone called?
Epiphysis
What gives rise to the primary palate?
The floor of the nasal cavity is formed by a posterior extension of the intermaxillary process called the primary palate.
What is fetal alcohol syndrome?
FAS is a mild form of holoprosencephaly. Each year between 5,000 to 12,000 American babies are born with it. They may grow slower than other children, have facial abnormalities, mental retardation. Facial features include small eyes with drooping upper eyelid, short upturned nose, flattened cheek, small jaw, thin upper lip, flattened philtrum. FAS is due to deficiencies of midline tissue of the neural plate very early in embryonic development.
What is amelogenesis imperfecta?
It can be inherited as an x-linked autosomal recessive or AD condition. Mutations in AMELX, ENAM, and MMP20 genes cause it. These genes provide instructions for making proteins essential to tooth development.
What are the two most common missing teeth?
Maxillary lateral incisors and mandibular 2nd premolars
What happens to thymus gland with DiGeorge syndrome?
It is small or missing, and mature T cells are absent and results in poor immune function and frequent infections.
What are the two layers that make up the reduced enamel epithelium?
A layer of ameloblast cells and cuboidal cells from the outer enamel epithelium.
What is the timeline for addressing an infant with cleft lip and cleft palate?
3 months - repair of cleft lip 6 months - pre-surgical orthopedics 9 months - speech therapy begins 9-12 months - repair of cleft palate Age 1 -7 - orthodontic treatment Age 7-8 - alveolar bone graft 8+ - orthodontic treatment
What is osteogenesis imperfecta?
May be seen alone or with dentinogenesis imperfecta, and it is a genetic disorder where bones break for no apparent cause, and is caused by mutations in one of several collagen producing genes, COL1A1 and COL1A2, creating a loss in the production of collagen. The teeth are discolored and show bulbous crowns and small pulp chambers.
What is Pierre Robin syndrome?
Is present at birth, infant has smaller than normal lower jaw, tongue falls back in throat, difficulty breathing. Can be caused by intrauterine folding or by changes in the DNA near the SOX9 gene. Usually not inherited. Also includes cleft soft palate, receding chin, small jaw, natal teeth. These babies frequently experience breathing difficulties, choking, congestive heart failure, low blood oxygen and brain damage, pulmonary hypertension.
Which two organs does PTH mainly act on?
Bone and Kidney
Normally, is most of the calcium that enters glomerular filtrate reabsorbed back into the blood, or excreted?
Reabsorbed back into blood to preserve blood calcium.
What 14 teratogens can cause craniofacial malformations?
- Alcohol - central midface deficiency 2. Hydantoin (anticonvulsant drugs) 3. Accutane - treacher collins 4. Toluene 5. Cigarette smoking - cleft lip and palate 6. Ionizing radiation - microcephaly 7. Aminopterin (chemotherapy) - anencephaly 8. Aspirin - cleft lip and palate 9. Cytomegalovirus - microcephaly, hydrocephaly 10. Dilantin - cleft lip and palate 11. Rubella virus - microphthalmia, cataracts, deafness 12. Thalidomide - treacher collins 13. Valium - treacher collins 14. Vitamin D excess - premature suture closure
What are some treatment options for amelogenesis imperfecta?
Crown, over-dentures, implants.
What is the central shaft of a long bone called?
Diaphysis
What nerve innervates all of the small salivary glands in the insides of the cheeks, tongue, lips, floor of mouth, sublingual gland, and submandibular gland, which are all below the level of the oral fissure?
Chorda tympani branch of the Facial nerve - CN VII
What are the two main drugs that can cause cleft lip?
- Phenytoin - anticonvulsant 2. Vitamin A (Accutane)
Which cells in bone does PTH stimulate?
The osteoclasts to cause bone resorption and increase blood calcium.
What are the two most common types of facial clefts?
Cleft lip and cleft palate
What do the neural crest cells that migrate to lower regions of the facial area help form?
Aorta, pulmonary artery, aortic arch, etc. This is why many syndromic patients have heart defects.
What is DiGeorge syndrome?
It is caused by a deletion in the long (q) arm of chromosome 22. 22q11.2 deletion. And this deletion leads to hypoplasia of 3rd and 4th pouch derivatives.
Phosphorus has no direct stimulatory effect on the parathryoid glands. True or False?
False. It has been shown recently to have an effect.
What happens during maturation stage of amelogenesis?
Ameloblasts transport substances used in the formation of enamel.These cells become striated and have a ruffled border. The ruffled border on the distal aspect helps increase the surface area of the ameloblast to help deliver matrix proteins. The prisms in the enamel grow in thickness, but not in length here.
Does ossification progress from posterior to anterior or anterior to posterior with the chondrocranium?
From posterior to anterior
What nerve supplies sensory to the parotid gland?
The auriculotemporal nerve of the mandibular branch of the trigemincal nerve - CN V.
What is the structure that divides the sensory and taste into two components of the tongue (posterior 1/3 and anterior 2/3)?
Terminal sulcus
Bone is always formed as a primary tissue. True or False?
False. It always replaces a preexisting support tissue, it is never formed as a primary tissue.
What is the process of remodeling?
The balance of apposition and resorption, with new bone being formed while old bone being removed. It is seen at the surfaces of bones that are growing by endochondral replacement as well as bones that are formed directly within a connective tissue membrane.
What nerve innervates all of the small salivary glands in the insides of the cheeks, lips, and hard palate, above the level of the oral fissure?
Greater petrosal branch of the Facial nerve - CN VII
During what weeks is the basic morphology of the face created by?
During weeks 4 through 10
When do craniosynostosis syndromes typically occur or form?
After 8 weeks, during fetal period rather than embryological period. They result form early closure of the sutures between the cranial and facial bones.
At what pH can damage start happening to fluoroapatite structures?
4.5
What does the intermaxillary process give rise to?
The philtrum of the upper lip.