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Flashcards in Ortho/Pedo Deck (153)
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1
Q

The condition known as “twinning” is also called ___ (the technical term)

A

Gemination

2
Q

The loss of tooth L in a 5-year-old patient requires ___ for space management. Why?

A

Band-and-loop

It will prevent the mesial movement of K into the space created by extracting L

It should be replaced with a lingual holding arch as soon as the other lower permanent incisors erupt

3
Q

Space maintainers should not be placed in children ___ years of age or younger

A

3

4
Q

What causes the discontinuity of the occlusal plane when an ankylosed tooth is present?

A

Continued eruption of non-ankylosed teeth and growth of the alveolar process

When teeth are ankylosed, they usually lie below the occlusal plane because the supporting alveolar process does not grow.

Alveolar process growth occurs simultaneously with the eruption of teeth. Ankylosed teeth do not experience alveolar process growth because of their failure to erupt the same way as the other non-ankylosed teeth due to a lack of PDL.

5
Q

___ is the term for a tooth that is traumatized without being displaced and can also increase the mobility of the tooth. ___ confirms the diagnosis.

A

Subluxation

Bleeding from the gingival sulcus

This trauma may require immediate dental treatment of the affected tooth

6
Q

___ occurs when there is an injury within the supporting structures of a traumatized tooth and does not demonstrate bleeding from the sulcus. Loosening and possible displacement among traumatized teeth is NOT observed.

A

Concussion

7
Q

To obtain optimal retention of a stainless steel crown in a primary mandibular molar, the __ surface should have the least amount of reduction.

A

Lingual

The lingual cervical bulge is smaller than the buccal so the lingual reduction must be minimal

8
Q

Fusion results from the union of two ___. It is usually found in ___ teeth.

A

Adjacent tooth buds

Anterior

9
Q

An anomaly in which there is a distortion of only the root of a tooth, which may be in the form of a right angle bend is a ___

A

Flexion

10
Q

What is the difference between a dilaceration and a flexion?

A

Flexion is distortion of the root portion only

Dilaceration is distortion of the root AND crown from their normally linear relationship

11
Q

What is concresence?

A

The union of the root structure of two or more teeth through cementum only

12
Q

What is a dwarfed root and a segmented root?

A

Dwarfed root - normal sized crowns with abnormally short roots

Segmented root - two separated root segments resulting from break in hertwig’s sheath

13
Q

Development of pulp necrosis is most commonly seen in what type of dental trauma?

A

Intrusion. It may sever the nerve and blood vessels that supply the tooth resulting in pulp necrosis. It may also cause replacement resorption of the roots or ankylosis

Concussion, extrusion, luxation, and subluxation are accidents that are less likely to involve the vascular supply of the tooth

14
Q

What is a flexion and how is it caused?

A

A deviation or a bend of less than 90 degrees at the root of tooth that results from trauma during development

15
Q

Dwarfed roots are normally found in ___ teeth, with __ being the most common

A

Anterior

Maxillary central incisors

16
Q

How is a dilaceration formed?

A

Likely resulted from trauma during development

Trauma during tooth development may result in the position of the calcified portion of the tooth being changed so that the remainder of the tooth is formed at an angle.

The curve or bend may occur anywhere along the length of the tooth and depends on the amount of root that is already formed when the injury is sustained.

17
Q

What teeth anomalies are associated with prenatal syphilis (caused by the bacteria:__)? How does it cause the anomaly? What teeth are they likely to affect?

A

Hutchinson’s teeth and mulberry molars

Treponema Pallidum

It disturbs the calcification of the teeth during the mopodifferentiation of ameloblasts

Incisors (maxillary central) and 1st molars are commonly affected because they are the only permanent teeth at this stage of development

18
Q

What is the primary concern of patients with Hutchinson’s teeth and mulberry molars?

A

Esthetics

19
Q

True or false.. prenatal syphillis affects primary teeth

A

False

20
Q

____ is an abnormal bone growth condition where normal bone is replaced with fibrous bone tissue, causing a “ground glass” appearance radiographically. Cortex may be thinned and displaced. The bones of the skull, thigh, shin, ribs, upper arm, and pelvis are most commonly affected. 70% are ___ and involve just one bone.

A

Fibrous dysplasia

Monostotic

21
Q

Fibrous dysplasia occurs 50% more frequently in the __ than the __

A

Mandible

Maxilla

22
Q

Describe the radiographic features of Fibrous Dysplasia

A

Ground glass appearance (radiopaque (usually or radiolucent)

Usually unilocular

Cortex thinned and may be displaced

Displaces anatomical structures and may or may not displace teeth

Poorly defined with no corticated border

Loss of lamina dura

23
Q

___ is a rare genetic disorder characterized by a bony prominence in the lower portion of the face and unerupted permanent teeth. It is also associated with premature deciduous tooth loss due to the sponge-like quality of bone. It is associated with the uneruption of permanent teeth due to displacement by cysts and lesions.

A

Cherubism

24
Q

True or false… in cherubism, the condition often fades as the child grows

A

True

25
Q

What are the ABCDEs of early signs of melanoma?

A
A-Asymmetry 
B-Border (irregular)
C- Color (multicolored)
D- Diameter (greater than about 6mm)
E- Evolving
26
Q

The most dangerous form of melanoma, ___, can be diagnosed by “EFG”. What does that stand for?

A

Nodular melanoma

E- Elevated above the skin surface
F- Firm to the touch
G- Growing

27
Q

What happens to the morphology of oral mucosa in an aspirin burn?

A

Tissue necrosis

The acetylsalicylic acid in aspirin burns the mucosa causing coagulation necrosis

28
Q

____ are congenital multiloculated lymphatic lesions that can arise anywhere but are classically found in the left posterior triangle of the neck in children. They are considered to be the most common form of lymphangioma. They contain large, cyst-like cavities containing lymph, and they decrease in size as they approach the surface of the skin. They are benign but can be disfiguring

A

Cystic hygromas

29
Q

What are the two types of cystic hygromas?

A

Macrocystic lymphatic malformations (large cysts)

Microcystic (small cysts

A person can have one type of a cyst or a mixture of both.

30
Q

True or false.. a cementoblastoma indicates the presence of a necrotic pulp

A

False

31
Q

____ are benign lesions that usually appear in males under the age of 25 and involve the permanent mandibular molars or premolars. They typically appear as a well-defined, marked radiopaque mass, with a radiolucent peripheral line, which overlies and obliterates the tooth tooth.

A

Cementoblastomas

32
Q

Describe how the sclerotic reaction of condensing osteitis occurs.

A

The sclerotic reaction results from a strong resistance of the patient and a low degree of virulence of the offending bacteria

33
Q

As enamel ages, it becomes ___, __, and ___.

A

Thinner

Less translucent

Worn

Younger teeth exhibit thicker, more translucent, and rougher enamel.

Adult teeth appear smoother, shorter, and darker

34
Q

Which Angle’s classification is most likely to occur as an adult when the primary second molar teeth exhibit a distal step?

A

Class 2

35
Q

Mesial step occlusion usually results either class __ or class __ molar relationships after eruption of permanent teeth.

A

1

3

36
Q

Children with a flush terminal plane occlusion, will end up in a class __, class __, or __ type of molar relationship

A

1

2

End to end

37
Q

A 10 year old patient presents to you with a 2.5mm diasterma and a low attached maxillary labial frenum. What is the best option for this patient? Why?

A

Observe until after eruption of permanent canines

Diastema in between maxillary central incisors normally occur during the mixed dentition stage. Eruption of maxillary canines in children ranging from age 11 to 12 usually will close the diastema between the maxillary central incisors.

38
Q

When is a frenectomy indicated in the case of a midline diastema?

A

If the maxillary canines had already erupted and were unable to close the diastema due to a lowly attached or fibrous maxillary labial frenum.

39
Q

The aging process causes the facial profile to become less __. How else is the face affected by aging?

A

Convex

Loss of facial fat, muscle atrophy, and loss of skin elasticity

The buccal fat pad is gradually lost in the cheeks causing the skin to adapt itself to the underlying muscle and bone

During the aging process, metabolism slows down and the production of skin, collagen, and muscle fibers is reduced. The constant pull of gravity also contributes to the sagging of the face.

40
Q

A 9 year old patient presents to your office with a unilateral posterior crossbite with a functional shift. What is the appropriate timing for correction of the crossbite?

A

Immediately, when the child is approximately 9 years of age.

Unilateral posterior crossbite are best treated immediately after their diagnosis

Treatment is most appropriate for children who are currently in the late deciduous at this age and more space is created to correct the malaignment

41
Q

Cervical pull headgear is an appliance used to correct ___ malocclusions with ___. The neck strap acts to ___. The outer bow connects the facebow assembly with the neck strap. The inner bow is inserted into the tubes found on the ___ bands/brackets.

A

Class 2

Deep bite

Extra-oral anchorage

Molar

42
Q

Cervical pull headgear inhibits the growth of the ___ and causes the ___ to extrude lessening the ___. The headgear must be worn regularly for ___ per day for optimal results.

A

Maxilla

Maxillary molars

Deep bite

12 hours

43
Q

The most common reason or improper speech sounds in cleft lip and palate patients is mainly due to…

A

Inability of the soft palate to close airflow into the nasal area and inability of the tongue to stop airflow from the epiglottis

44
Q

What is the sequence of eruption for primary teeth?

A

Central incisor, lateral incisor, first molar, canine, second molar

45
Q

Loops and helices are incorporated into arch wire to…

A

Improve activation range. Activation is created by slightly closing the loops and helices with a pair of pliers.

Archwires need to be activated to achieve the desired results as it becomes loose after moving teeth in the desired direction decreasing the tension on the arch wire.

Closing the loops and helices result in the tightening of arch wire.

46
Q

Due to the long axis of the teeth, the spontaneous closure of the extraction space in the ___ arch is better than the __ arch.

A

Upper

Lower

47
Q

During the eruption of the permanent 2nd and 3rd molars, what portions of the developing mandible help provide space?

A

Resorption at the anterior border of the ramus while bone is simultaneously deposited at the posterior border of the ramus. This helps maintain the ramus width while providing extra alveolar bone space for the erupting molars.

48
Q

True or false… condylar hypertrophy cannot cause an anterior open bite

A

True

49
Q

In order to effectively translate the roots of teeth, orthodontic appliances must be capable of..

A

Exerting a torque/movement coupling action.

50
Q

Approximately __-__g of force is needed to uniformly load the PDL to create translational movement.

A

100-150

51
Q

A higher-than-average mandibular plane angle indicates a [horizontal/vertical] growth pattern and an [increased/decreased] lower anterior face height

A

Vertical

Increased.

52
Q

True or false.. patients with deep overbites and a vertical growth pattern may exhibit steep mandibular plane angles but NOT a long lower anterior face height due to the type of dental occlusion that the patient demonstrates

A

True

53
Q

Approximately __% of a permanent tooth’s root structure has typically developed right before the tooth first emerges into the oral cavity

A

66% (2/3rds)

The tooth begins to erupt when the root reaches about 2/3 of its complete form.

54
Q

Vertical growth of the mandible is attributed to growth of the __

A

Condylar head

55
Q

Primary tooth formation begins ___ -___ weeks in utero. Calcification of primary teeth begins during the ___ trimester.

A

6-8 weeks

2nd trimester (14th - 19th week)

56
Q

The cusp of carabeli is a feature most commonly found on which Primary tooth? Which permanent tooth? Which cusp is it on?

A

Maxillary 2nd molar

Maxillary first molar

Lingual to the ML cusp

57
Q

What is adjunctive orthodontics?

A

Adjunctive orthodontic treatment integrates favorable orthodontic tooth movement into a treatment plan together with other dental procedures (perio, prosth, operative).

This also eliminates unnecessary tooth extractions, tooth preparations, and other periodontal, preprosthetic, or pre-restorative treatment to achieve more optimal outcomes

58
Q

Cervical pull headgear is an appliance used to reduce ___ growth of the maxilla.

A

Forward

59
Q

Which tooth is most likely to NOT erupt in the arch due to overcrowding?

A

Canine (because they come in after the incisors and premolars have already erupted)

Tooth crowding carries a genetic predisposition because it is often a matter of tooth size vs arch size discrepancy

60
Q

The permanent molars shift mesially to close which space?

A

Leeway space - created from the difference of sizes between the primary canine and molars compared to the erupting premolars and permanent canines

61
Q

Which cephalometric measurement value indicates that if the maxilla is protruded or returned?

A

SNA (sella-nasion-A point)

62
Q

The __ cephalometric value is a useful guide in determining the relation of maxilla to the mandible.

A

ANB

63
Q

During postnatal growth of the maxilla, an increas in maxillary height and depth of the palate is atributed to growth of the __

A

Alveolar bone

64
Q

A 6-year-old presents with need of extraction of L and S. The mandibular incisors have not yet erupted. The indicated method of space maintenance for this patient is…

A

Bilateral band and loops because the mandibular permanent incisors have not yet erupted.

65
Q

___ appliances are cemented on the maxillary permanent first molars and have an acrylic button that rests on the palate to resist forward movement

A

Nance

66
Q

Which three planes of space are used to classify malocclusion? Describe what each plane defines.

A

Sagittal - describes AP relationships (class 1, 2, 3)

Transverse - describes right to left relationships that are predominantly caused by a constriction of the dental arches (unilateral or bilateral crossbite)

Vertical plane - used to give the superior-inferior relationships (deep bite or open bite)

Vertical

67
Q

In a pt with class 3 skeletal malocclusion, which cephalometric measurement is increased?

A

SNB (sella-nasion-B point) (over 80degrees)

SNB under 80 degrees is recursive mandible

68
Q

What is the most ideal media to store an avulsed tooth that preserves the viability of the PDL?

A

Hank’s balanced salt solution

It has the ability to keep the cells surrounding the root viable

It has a rich amount of metabolites such as Ca, K, glucose, and phosphate ions that are sufficient to provide the cells with energy to sustain their normal cell metabolism until replantation can occur

HBSS also has a balanced pH and is known to hep replenish lost metabolites within the PDL cells of an avulsed tooth. It helps improve the prognosis of replantation and decreases the chances of having replacement resorption

69
Q

What is the most likely outcome of an intruded permanent incisor in a 7 year old child in a few weeks after the trauma?

A

Re-eruption

An intruded permanent central incisor will eventually start to re-erupt within a period of approximately 2-3 weeks

The deicision on the mode of treatment for an intruded tooth may vary depending upon the severity of tooth intrusion and the maturity of its roots

70
Q

Name 3 modalities of treatment for an intruded tooth.

A

Passive reposition which provides enough time for the re-eruption of intruded tooth

Active repositioning which is performed through surgical repositioning

Orthodontic repositioning which is achieved with the use of removal or fixed appliances

71
Q

Trauma incurred to a developing tooth bud during the initiation and proliferation phase will likely result in an alteration in…

A

Number of teeth

Abnormalities in the number of teeth manifest from a disturbance during the initiation and proliferation stages of tooth development, hypodonti, oligodontia, anodontia, hyperdontia, and supernumerary teeth are various developmental disturbances that can affect the number of teeth present.

72
Q

What is the difference of hypodontia and oligodontia?

A

Hypodontia - there are fewer than six congenitally missing teeth. It is also known as partial anodontia

Oligodontia - there are 6 or more congenitally missing teeth

73
Q

When the ___ tooth erupts, it moves mesially and maintains a stable position within the corner of the mandibular arch

A

Permanent mandibular canine

74
Q

When is a direct pulp cap Of a non carious exposure contraindicated?

A

When the pulp has been exposed for more than an hour

75
Q

A patient presenting with teeth that appear to have bulbous crowns, an absence of a root canal system, and short roots radiographically likely has what condition?

A

Osteogenesis imperfecta

76
Q

____ is the most common congenital bone disorder where patients are born with defective connective tissue, or without the ability to make it usually because of deficiency of type 1 collagen.

A

Osteogenesis imperfecta

77
Q

____ is suggested radiographically by a thin bone cortex and bulbous crowns, obliterated pulps, and shortened tooth roots. The teeth are described as shell-like because the enamel may fracture and increased wear can occur.

A

Osteogenesis imperfecta

78
Q

In osteogenesis imperfecta, Type 1 collagen is of normal ___ but is produced in insufficient ___. It results in ___ and ___.

A

Quality

Quantity

Blue sclera and easily fractured bones

79
Q

In osteogenesis imperfecta, type 2 collagen is not of a sufficient ___. It results in what three things?

A

Quality or quantity

Most cases die within the first year of life due to respiratory failure or intracerebral hemorrhage

Patients have severe respiratory problems due to underdeveloped lungs

Patients have severe bone deformity and small stature

80
Q

In primary teeth, what is the least reliable in assessing the pulp vitality?

A

Pulp testing

81
Q

Name 5 prodromal symptoms of herpetic gingivostomatitis

A

Fever

Anorexia

Irritability

Malaise

Headache

82
Q

At which stage of tooth development is tetracycline incorporated into the developing tooth?

A

Mineralization - because it forms a chelate with calcium

Tetracycline staining is found in both the enamel and dentin. When first incorporated into the tooth structure, tetracycline produces a yellow color that changes to brown and grey with the addition of sunlight over time.

83
Q

Congenital syphilis is associated with ___ incisors occurring in months __-__ in utero before calcification begins.

A

Hutchinson’s

4-6

84
Q

How are enamelomas (enamel pearls) formed?

A

During tooth development when the cells of the epithelial root sheath remains stuck to predentin. They then differentiate into ameloblasts and deposit enamel where it normally would not.

85
Q

A child exhibiting signs and symptoms of failure to thrive, such as enamel hypoplasia, might also be suffering from which of the following conditions?

A

Ectodermal dysplasia

Ectodermal dysplasia may affect all types of tissues that originated form the ectodermal embryonic layer. Patients with ectodermal dysplasia may also suffer incomplete development of hair, nails, sweat glands, enamel of the teeth, and even the oil glands.

86
Q

In a ____ mixed dentition analysis, the measurements of ___ will indicate the space that will be occupied by the unerupted canines and premolars.

A

Mandibular incisors

It uses the total MD width of the mandibular central and lateral incisors to predict the size of the unerupted canines and premolars.

87
Q

What is the most likely age range for a primary herpetic gingivostomatitis episode?

A

1-5 years

88
Q

Secondary herpetic gingivostomatitis is a deactivation of the latent virus due to ___, __, or ___. The vesicles may be found intraorally or exterorally on ___ surfaces.

A

Trauma, stress, immunosuppression

Keratinized

89
Q

Following facial trauma, an 8-year old pt presents with a fractured central incisor that has an exposed pulp. Radiographic assessment shows the tooth still has an open apex. The pulp tissue appear to be vital and the tooth is non-mobile. What is the indicated treatment?

A

Pulpotomy with calcium hydroxide (cvek pulpotomy)

The root apex of developing permanent central incisor is still open. By performing a Cvek pulpotomy, the root of the central incisor will have extra time to complete its root development. (Pulpotomies are only performed as a temporary treatment option in permanent teeth while you wait for the roots of the tooth to fully develop so a root canal treatment can be performed)

90
Q

A partial pulpotomy for traumatic exposures is also called ___

A

A cvek pulpotomy

91
Q

What is the most common (75% of cases) type of leukemia in children?

A

ALL (acute lymphoblastic leukemia)

92
Q

True or false… epinephrine in local anesthetics are contraindicated in patients with multiple sclerosis.

A

True, because it can aggravate the condition by regulating the activation of blood lymphocytes.

Elevating the levels of epinephrine also increases blood lymphocyte activity which could cause further damage to the myelin sheaths of the neurons thereby aggravating the multiple sclerosis condition

93
Q

True or false… due to the long axis of the teeth, the spontaneous closure of extraction spaces in the mandibular arch is more successful than in the maxilla

A

False.. the upper arch is better than the lower arch

94
Q

What is the greatest risk to a patient with adrenal insufficeincy if they are subjected to a highly stressful situation?

A

Cardiovascular collapse

Adrenal insufficiency occurs when the adrenal glands produce insufficient amounts of steroid hormones like cortisol and aldosterone.

95
Q

Cortisol stimulates ___ in the liver.

A

Gluconeogenesis

It helps maintain normal blood pressure during stressful situations and creates additional energy to cope up with such stress

96
Q

What are the signs and symptoms of Cushing’s syndrome?

A

Extreme weight gain

Buffalo hump (fat deposition in the upper central back)

Moodiness, irritability, or depression

Muscle and bone weakness

Memory and attention dysfunction

Osteoporosis

Diabetes mellitus

Hypertension, immune suppression, sleep disturbances

Menstrual disorders, hirsutism, baldness, hypercholestroemia edema

97
Q

What are the 5 domains of pediatric patient management?

A

Aversive (punishments)

Linguistic

Pharmacological

Reward-oriented

Physical

98
Q

Incidence of ____ is a condition in which cementum overlying the roots of at least two teeth connects to join the teeth together. It is more common in cases of trauma or crowding of teeth. This condition is most common in ____ teeth. How is it different from fusion?

A

Concrescence

Permanent molar

Different from fusion because it occurs following eruption and involves only cementum

99
Q

True or false… crossbite can be corrected immediately during the primary dentition

A

True

100
Q

What is methylphenidate?

A

A psychostimulant approved in treating people with ADHD.

101
Q

Methylphenidate reduces the ___ and ___ reuptake, increasing their levels thereby improving their function as neurotransmitters in the brain. It elicits a similar pharmacological effect to cocaine. However this drug has a lower level of ___ and duration is [longer/shorter].

A

Dopamine and norepinephrine

Potency

Longer

102
Q

Rheumatic fever is an inflammatory disease that occurs after a ___ infection or ___ and is caused by antibody cross-reactivity from the ___ protein.

A

Streptococcus pyogenes

Scarlet fever

Strep M

103
Q

What are the Major criteria under the Jones classification of Rheumatic fever?

A

Polyarthritis

Cariditis

Subcutaneous nodules

Erythema marginatum

Chorea (St. Vitus’ dance)

104
Q

____ is a condition comprised of generalized exocrine dysfunction, steatorrhea, and chronic pulmonary disease. It is a genetic disorder resulting in the inability of the body to transport salt and water in and out of cells. The result is excessive production of sticky and viscous mucus in the lungs and digestive tract. It affects the production of digestive enzymes that break down fats causing them to not be absorbed, resulting in a fatty stool called steatorrhea.

A

Cystic fibrosis

105
Q

____ is fracture lines that do not extend into dentin.

A

Crazing

106
Q

Name 5 potential causes of orofacial clefting.

A

Maternal nutrition - low intake of folic acid

Alcohol and cigarette use

Nitrate compounds and organic solvents

Lead

Medications

107
Q

During the ___ in utero, when orofacial clefting may occur, the embryo is very sensitive to environmental pollutants and malnutrition

A

Sixth week

108
Q

Piezoelectric currents are important for ___, not ____.

A

Bone maintenance

Orthodontic tooth movement

109
Q

It takes ____s for fluid to be expressed from the PDL and the tooth moves in the socket

A

1-2s

110
Q

What occurs after 3-5s of light force?

What occurs after 3-5s of heavy force?

A

Blood vessels distorted, no pain.

Blood vessels occluded. Pain is produced from crushing pressure.

111
Q

What occurs after minutes of light force?

What occurs after minutes of heavy force?

A

Blood flow and oxygen levels altered. Increased prostaglandin and RANKL

Blood flow is cut off

112
Q

_____ resorption occurs with light force after ~___days. It involves both osteoclasts and osteoblasts

A

True

2

113
Q

____ resorption begins after ~___ days of heavy force, it ends after ____ days

A

Undermining

3-5

7-14

114
Q

In light force… the first wave of osteoclasts/osteoblasts come from ___. Later, the second wave comes from ___.

A

The PDL

The blood supply

115
Q

What occurs after hours of application of a heavy force?

A

Sterile necrosis (no bacteria involved)

Hyalinized PDL (no cells)

116
Q

How long does it take after sterile necrosis and after tooth movement via undermining resorption to heal before the next adjustment?

A

~2 weeks

117
Q

Remodeling of gingival fibers takes about ___, which is why you want to wear your retainer as much as possible after orthodontic treatment.

A

1 year

118
Q

In controlled tipping, where is the center of rotation?

A

At the apex of the root

119
Q

In bodily movement, where is the center of rotation?

A

Infinitely past the apex

120
Q

When torquing, where is the center of rotation moved?

A

Coronally

121
Q

What is the optimal force for bodily movement of teeth?

A

100g

122
Q

What is the absolute minimum for tooth movement to occur?

A

4-8 hours

The longer you have an appliance working the better

123
Q

Patient-activated removable display a ___ type of force decay

A

Intermittent

124
Q

What type of force decay do we want for light forces? What about heavy?

A

Light = continuous

Heavy = interrupted

125
Q

Define stress and strain

A

Stress = internal force

Strain = internal displacement

126
Q

Stress is measured in ___

Strain is measured in ___

A

Mega pascals

Mm

127
Q

What is the difference between elastic deformation and plastic deformation?

A

Elastic deformation = goes back to its original shape

Plastic deformation = doesn’t return to its original shape. It undergoes a permanent change

128
Q

When stress/strain have a linear relationship, the slope is called the ___. The steeper the slope the more [elastic/stiff] that material is.

A

Elastic modulus (modulus of elasticity)

Stiff

129
Q

What is the proportional limit?

What is the yield point (yield strength)?

A

proportional limit = The highest point on the stress/strain curve that is still linear. Once you get past this, it isn’t completely elastic

Yield point = initial point where plastic deformation begins

130
Q

What is ultimate tensile strength?

A

Maximum load an object can withstand

131
Q

What is the area under the stress-strain curve of the elastic portion? What does it mean?

A

Resilience = energy storage capacity of the object as you are stretching it

132
Q

What is the area under the stress/strain curve of the plastic deformation curve? What does it mean?

A

Formability = the ability to undergo plastic deformation without breaking

133
Q

If you double the diameter of a wire, you increase strength __X. Increase stiffness ___X. And decrease range by ___.

A

8x

16x

1/2

134
Q

If you double the lengthening of a wire you ___ the strength, but make it ___X springer and ___x more range

A

Half

8x

4x

135
Q

A wire that is attached to two teeth by two brackets is considered a ___ beam. If it is loosely attached it increases strength by __x. If it is tightly fixed the strength increases by ___.

A

Supporting

2x

4x

136
Q

Rubber bands have a great ___ range. They ___ easily. And they provide ___ forces rather than __.

A

Elastic

Fatigue

Interrupted rather than continuous

137
Q

What is a pseudo class 3 malocclusion?

A

They start out as end-end in CR but then protrude to a functional occlusion in MI with their mandibular incisors anterior to maxillary incisors

If not treated it can lead to tooth wear and/or perio problems

138
Q

What is the treatment for a dental anterior crossbite?

A

Tip maxillary incisors labially

Add a bulk of acrylic to the removable appliance (Hawley retainer) to separate the arches and prevent occlusal interference during tooth movement

139
Q

A fingerspring works effectively for ___-___ mm of activation. It affords to ___mm of tooth movement/month

A

2-3mm

1mm

140
Q

Where should the helix be placed in a finger spring?

A

Opposite to direction of intended tooth movement (usually MD)

141
Q

What is a Z-spring?

A

Double cantilever

Second beam with a second helix.

2mm of activation per helix.

142
Q

A Z-spring usually allows for __ movement

A

FL

143
Q

What is a whip spring?

A

Attached to a fixed lingual arch and functions to tip incisors labially

Allows for 1mm/month

144
Q

What is the best option for retention following correction of a crossbite?

A

Hawley retainer

145
Q

How do you treat a skeletal class 3 malocclusion due to maxillary deficiency with growth modification?

A

Reverse pull headgear

146
Q

At what age should reverse pull headgear be used?

A

Age 7 or 8, before skull fissures fuse

147
Q

How can you treat a skeletal class 3 malocclusion using fixed appliances?

A

Class 3 elastics

Age 11, TADs with mature bone

148
Q

What is the “rule of thumb”

A

Put your thumb at the top of the palate, if it fits, the posterior crossbite is likely due to lingual tipping

If the thumb doesn’t fit it means the crossbite is likely due to a narrow palate (narrow palatal vault)

149
Q

What can thumb-sucking habit cause?

A

Maxillary constriction from buccinator

Unilateral posterior crossbite due to functional shift

Tooth wear, dental compensation, crowding

150
Q

How do you treat posterior dental crossbite (palatal tipping of maxillary teeth)?

A

Expansion of lingual arches (slow expansion) for primary and early mixed

151
Q

A W-arch for expansion is usually made with a ___ wire. It is used at age __-__. You can expect to get ___mm/month.

A

.036” SS

8-11 (when midpalatal suture is open)

2mm

Some suture opening may occur

152
Q

A quad helix appliance is made with ___wire. It has 4 helices so it has a better range of action. Treatment is usually __-__ months. It should be worn for ___ months for retention.

A

.038” SS

2-3 months

3

153
Q

When would cross-elastics be used?

It may cause ___ as a side effect.

The amount of force is ___

A

For unilateral or individual teeth in crossbite

Use a mandibular lingual arch to stabilize lowers

It may cause some extrusion

150-170g