what is the normal overbite
20% plus or minus 5%
overbite is _______ related to severity of malocclusion
not related
what are the etiological factors for an overbite
- over eruption of upper incisors
- over eruption of lower incisors
- under eruption of lower posterior teeth
- genetic development- class II div 2
what is involved in a class II deep bite
- over eruption of maxillary incisors
- over eruption of mandibular incisors
what are the treatment options of the class II deep bite
treatment options should include active intrusion of the incisors
what does the intrusion arch do
correct the two step occlusal plane
what happens when leveling the curve of spee
- maxillary incisors have been intruded
- leveling the lower arch by incisor intrusion
- extrusion of mandibular posterior teeth
what is a way to avoid relapse of overbite
a hawley retainer with an anterior bite plate to maintain the corrected overbite
what do you do with an overbite with mandibular incisor intrustion
- bite opening with posterior blocks
- intrusion of lower incisors with light wire and constant force
- upper incisors are left at the same level
what are the treatment options for extrusion of posterior segments combined with maxillary incisor intrusion
- bite plate at night
- lower intrusion arch
- cervical pull HG to correct class II molar relation, extrude molars
- intrusion arch for maxillary incisors, lower molar eruption with a bite plate
what are the origins of an open bite
- genetic origin
- functional origin
- parafunctional habits
- combination
what are the multifactorial etiologies of an open bite
- skeletal (genetic)
- tongue thrust
- finger habit
- sleep apnea
- neuromuscular
what malocclusions are anterior open bites present in
a multitude of malocclusions
etiologies for open bite are:
ill defined
is the relapse rate higher for open bites or non open bite malocclusions
open bites
what is the facial type, lip support, lip seal, upper incisor showing at rest, smile line, facial proportions in an open bite
- facial type: variable usually dolychocephalic tendency
- lip support: altered
- lip seal: deficient
- upper incisor showing at rest: variable but usually increased
- smile line: altered
- facial proportions: variable
what is the dentoalveolar response causing an open bite
- displacement of maxillary incisors in the vertical and AP plane
- intrusion and proclination of mandibular incisors
- over eruption of maxillary and/or mandibular molars
what is assessed in the occlusal plane analysis
the position of posterior and anterior teeth in relation to the functional occlusal plane
why is the occlusal plane hard to determine
the anterior teeth are often times displaced in the vertical plane
what is the DDX for open bite
- anterior tongue posture
- thumb sucking habit
- genetics
- sleep apnea
- combination
what are the parafunctional habits affecting open bites
- thumb sucking
- anterior tongue posture
- dentoalveolar deformation and lack of tooth eruption
what are the tx options for a thumb sucking pt
- fixed appliances
- tongue crib
- psychological support
- myofunctional therapy
what is the AOB neuromuscular origin
- anterior tongue posture
- maxillary incisors pushed labially
- mandibular incisors under erupted
- good posterior occlusion
- good facial balance
what is the ismar modified appliance used for
open bites
