Orthodontics BDS3 Flashcards
name 5 investigations required for orthodontic diagnosis
study models
radiographs
photographs
sensibility tests
CBCT
what is the aim of orthodontic treatment
to have a stable functional and aesthetic occlusion
what are the three main risks of orthodontic treatment
decalcification
root resorption
relapse
when should children first be examined to see if they will need ortho treatment
9 years old in the mixed dentition
name andrew’s six keys
molar relationship
crown angulation
crown inclination
no rotations
no spaces
flat occlusal plane
what three planes is the facial skeleton considered in
Anetero-posterior
vertical
transverse
how do you assess the AP relationship
visual assessment
palpate cranial base
how is the vertical relationship assessed
using the frankfort mandibular planes angle
name five occlusal effects of sucking habit
proclination of upper anteriors
retroclination of lower anteriors
localised AOB
narrow upper arch
unilateral crossbite
what is an AP class I
SNA of 81 (plus or minus 3)
SNB of 78 (plus or minus 3)
ANB of 3 (plus or minus 2)
what is an AP class II
SNA usually averaged
SNB decreased
ANB of more than 5
what is an AP class III
SNA decreased
SNB average or increased if mandible prognathic
ANB less than 1 or negative
where is the upper anterior face height taken from
glabella to base of nose
where is the lower anterior face height taken from
base of nose to the inferior aspect of chin
what is the average value of the FMPA
27 plus or minus 4
what growth rotation is associated with a long facial type
backwards mandibular growth rotation
what growth rotation is associated with a short facial height
forward mandibular growth rotation
what are the five aspects of local causes of malocclusion
variation in tooth number
variation in tooth size
abnormalities of tooth position
local abnormalities of soft tissue
local pathology
what are the four types of supernumerary teeth
conical
tuberculate
supplemental
odontome
why may teeth be retained
absent successor
extopic successor
infra-occluded
what is a balancing extraction
extracting a tooth of the opposite side of same arch to minimise midline shift
what is compensating extraction
extraction of tooth on opposing arch of same side to maintain occlusal relationship
when will a tooth not move
if is ankylosed or has no PDL
what happens to bone in areas of compression
bone is resorbed
what happens to bone in areas of tension
bone is deposited
