Growth And Development Flashcards
At what age do females and males reach PHV (peak height velocity)?
Females = 11.9 years
Males = 14.0 years
At what age does girls and boys initiate adolescence?
Girls = 9.4 years
Boys = 11.2 years
What is the mild-childhood growth spurt? When does it typically occur?
The increase in growth velocity that occurs in some, but not all, children several years before adolescence.
Occurs between 6.5 and 8.5 years of age.
True or false… the mid-childhood growth spurt more often occurs in girls than boys.
False… it tends to occur more frequently in boys than girls
Which skeletal (Hand) indicators are most closely associated with peak height velocity?
PHV in males and females occurs slightly after the appearance of the ulnar sesamoid and the hooking hooking of the hamate, and slightly before capping of the third middle phalanx, the capping of the first proximal phalanx, and the capping of the radius.
Which skeletal indicators (cervical vertebrae) are most closely associated with peak height velocity?
PHV occurs between cervical vertebral maturation stage CS3 (concavities on the inferior borders of the second and third vertebrae, and both the third and fourth vertebrae are either trapezoid or rectangular horizontal in shape) and CS4 (concavities on the inferior borders of the second, third, and fourth vertebrae, and both the third and fourth vertebrae are rectangular horizontal in shape).
What are three conclusions that are drawn from the equilibrium theory of tooth position?
The forces (produced naturally or by orthodontic appliances) extorted on the crowns of teeth are sufficient to cause tooth movements
Each tooth may have more than one stable state of equilibrium
Even small forces (3-7 grams), if applied over a long enough period can cause tooth movements.
What are the primary factors involved in the equilibrium theory of tooth position?
Pressures of the lips, cheeks, and tongue
As well as the eruptive forces produced by metabolic activity within the periodontal membrane.
Extrinsic pressures, such as habits and orthodontic forces, can alter dentoalveolar equilibrium provided that they are sustained for at least 6 hours each day.
Which, the maxilla or mandible, contributes the most to class 3 malocclusions?
The mandible
Do third molars play a role in determining crowding?
Although third molars have been related with crowding, most contemporary studies show little or no relationship.
The NIH determined that there is little to no justification for extracting third molars solely to minimize present or future crowding of the lower anterior teeth.
True or false… anterior growth of the mandible significantly contributes to mandibular incisor crowding as it pushes the incisors in the the lower lip.
False. Although incisor compensation to back-ward mandibular rotation has been demonstrated, crowding as a result of anterior growth displacements remain to be established. However, changes in lower incisors crowding have been shown to be related to VERTICAL growth.
those who undergro greater inferior growth displacements of the mandible, and associated greater eruption of the lower incisors, show greater crowding than those who undergo less vertical growth and less eruption.
How much should the maxillary and mandibular incisors and molars be expected to erupt during adolescence? (Between ages 10-15)
Maxillary first molars 5-6mm
Maxillary central incisors
4.5-5mm
Mandibular molars
3-5.5mm
Mandibular incisors
2.5-4.5
Males showed greater eruption than females
How do untreated maxillary and mandibular intermolar widths change during childhood and adolescence?
Increases 7-8mm between age 5 - age 8. Then an additional 1-2mm between age 8 and age 12.5.
During the transition from the deciduous to permanent incisors, mandibular intercanine width increases approximately ___. Maxillary intercanine width also increases, approximately __. Mandibular intercanine widths decrease slightly after the emergence of the permenent canine.
3mm
1.5 - 2mm
True or false.. maxillary intermolar widths were significantly smaller in subjects with Class 2 division 1 malocclusion than subjects with Class 2 division 2.
True
The narrow maxillary arch of division 1 subjects was apparent at 7 years of age and persisted through age 15.
class 2 division 2 malocclusion have __ and __ maxillary arches, whereas class 2 division 1 have __ and ___ maxillary arches
Short and wide
Long and narrow
True or false.. growth spurts do NOT occur in the AP position of either the maxilla or mandible
True. In other words, the chin does not undergo an anteriorly-directed growth spurt. However, the vertical aspects of both maxillary and mandibular growth exhibit adolescent spurts with peaks.
True or false.. peak maxillary growth velocities are usually attained more than 6 months before peak mandibular velocities. The maxilla tends to peak before PHV, whereas the mandible peaks after PHV.
True
Approximately __% of 10-year-olds are classified as prognathic or retrognathic, changing to orthognathic by age 15.
30%
Approximately __% of those who are orthognathic at 10 years of age become either prognathic or retrognathic at age 15.
30%
Between ages __ and ___, fore every 1mm the maxillary width increased, the mandibular width increased ___.
12 and 18
0.7mm
__ and ___ displacement of the glenoid fossa should be expected to occur along with growth of the sphenoid-occipital synchondrosis, elongation of the posterior cranial base, and associated displacement of the temporal bone.
Inferior and posterior
The distance between the glenoid fossa and nasion increases ___mm between 12 and 20 years of age.
7.5mm
The condyle grows __ and slightly __, whereas the gonion drifts ___ and ___ in approximately equal amounts
Superiorly
Posteriorly
Superiorly
Posteriorly
The closure of the mid palatal and transverse sutures can begin as early as ___ years of age but can be delayed in some individuals into the late ___.
15
20s or early 30s
Midpalatal sutures show evidence of growth through 16 years of age infemales and 18 years of age in males.
True or false… even though sutures start closing in adults, only relatively small portions of the sutures exhibit true fusion
True
The cranial base lengths (SN, BaN, BaS) and mandibular lengths (Ar-Go, Go-Gn, Ar-Gn) attained their maximum lengths between ages __ and __, after which they shortened slightly
29 and 39
