Class 2 Division 1 Malocclusion Flashcards
what is the BSI definition of class 2 division 1 malocclusion
lower incisor edges lie posterior to the cingulum plateau of the upper incisors. there is an increased overjet and the upper centrals are proclined or of average inclination
why would you treat class 2 div 1
aesthetic concerns
trauma if incompetent lips or overjet >9mm
what is the AP skeletal pattern like for class 2 div 1
class 2 AP skeletal base (sometimes class 1)
retrognathic mandible more common than prognathic maxilla
what can cause an overjet
skeletal pattern
tooth inclination
combination of both
lower lip trap
why would the lips be incompetent
prominence of incisors
underlying skeletal pattern
how would someone with incompetent lips achieve an oral seal
by muscle activity
mandible postured to allow lips to meet
lower lip drawn up behind the upper incisors
tongue placed forwards between incisors to lower lip
what are the dental factors of class 2 div 1 malocclusion
increased overjet
variable overbite
crowding/spacing/or good alignment
molar relationship
dry gingiva if parted lips
what kind of sucking habits could a patient have
thumb
fingers
blanket
lip
combination
non-nutritive sucking habit
what are the occlusal features of class 2 div 1
proclination of upper anteriors
retroclination of lower anteriors
localised AOB or incomplete OB
narrow upper arch
what are the treatment principles of habits
stop habit - reinforcement, appliances
allow spontaneous improvement
treat residual malocclusion if required
what are the management options for class 2 div 1
accept
attempt growth modification
simple tipping of teeth
camouflage
orthognathic surgery
when would you accept a class 2 div 1
mildly increased overjet
significant overjet but not unhappy
what advice is given to a patient if they choose to accept a class 2 div 1
wear mouthguard for sports
what are the ways of growth modification
headgear
functional appliance
what is the function of headgear
restrain growth of maxilla horizontally/vertically by using the top of the skull as anchorage
what does a functional appliance do
utilise, eliminate or guide the forces of muscle function, tooth eruption and growth to correct a malocclusion
give an example of a functional appliance
twin block (removable)
what are the aims of a functional appliance
produce restraint of maxillary growth and encourage mandibular growth
what does the success of a functional appliance depend on
favourable growth and enthusiastic patient
what are the dento-alveolar changes with a functional appliances
distal movement of uppers
mesial movement of lowers
retroclination of upper incisors
proclination of lower incisors
what degree of skeletal change can be made with a functional appliance
1-2mm
when is a functional appliance used
during growth
early = 10yrs old
late = late mixed/early permanent
what are the advantages of using a functional appliance in early stages
improve appearance earlier
reduce trauma risk
better compliance
what are the disadvantages of using a functional appliance in early stages
skeletal effects not maintained
treatment time increased - 2 phases (functional and fixed)
when is a URA not used
mild class 2 or class 1
overjet is due to proclined and spaced incisors
overbite is favourable
what is the appliance design for retroclining anterior teeth
active = roberts retractor 0.5mm tubing
retention = adams clasps on 6s 0.7mm HSSW
anchorage = stops mesial to canines
baseplate = flat anterior biteplane
what is the goal of camouflaging a class 2 div 1 and how is it achieved
reducing the overjet
upper arch extractions to give space
when is orthognathic surgery carried out
when growth is complete
what cases would get orthognathic surgery
skeletal discrepancy is severe in AP or vertical direction
