Increased Overbite & Class II Div 2 Flashcards
Definition of increased overbite (deep bite)
overlapping of the upper anterior teeth over the lowers in a vertical plane
Describe increased overbite
upper incisors overlap lowers by more than 4mm
Describe reduced overbite
less than 3mm overlap
Significance of Increased overbite
Why to refer patient for treatment?
•Trauma – soft tissues of anterior palate
•Prevents overjet reduction during treatment
•Dentofacial aesthetics
•Restorative difficulties
Typical extraoral features of increased overbite ?
•Reduced lower face height
•Often Class II
Incidence of Increased Overbite
•Common in many malocclusions
•Most Class II Div 2 malocclusions
•Many Class II Div 1 malocclusions
•Some Class III and Class I malocclusions
Aetiology of Increased Overbite
•AP skeletal discrepancy (Class II, III)
•Increased interincisal angle (Class II Div2)
•Reduced lower face height
•Unopposed lower incisors
Treatment of increased overbite: Why?
•Allow overjet reduction
•Facilitate a Class I incisor
relationship
•Improve post-treatment stability
•Facilitate restorative treatment
Reducing an Increased Overbite
1. Growing patients (ie. <14 years old)
•Anterior Biteplane
•Functional Appliance (eg. Andresen, Twinblock)
•Fixed appliances
Reducing an Increased Overbite
2. Non-growing patients (>14 years old)
•Orthognathic surgery often required
•Sometimes fixed appliances alone
•Therefore refer deep bite patients early
Anterior Biteplane – how does it work for growing patient?
•Biteplane only contacts with lower incisors
•Posterior mandibular rotation
•Eruption of molars
Use of Functional Appliances in treatment of deep overbites …
What malocclusion are they used to treat ?
Class II Div 1 malocclusions
How do functional appliances help to treat Class II div 1 malocclusions (deep overbite)
. Anterior biteplane effect, the posterior teeth are separated vertically when wearing the appliance
•Trimming posterior inter-occlusal acrylic allows eruption of posterior teeth
•This also facilitates full overjet reduction
How to fixed appliances help to treat deep overbites?
Reduction in overbite is
•Mostly due to molar extrusion
•Some incisor intrusion is possible
Increased Overbite: Summary
•Increased overbite is a …
common feature
Correction of increased overbite allows …
full overjet reduction
Correction of increased overbite is easiest in
growing patients, usually in the late mixed or early permanent dentitions
Correction of deep overbites in .. is most difficult and often requires …
Adults
Surgery
When to refer patients with deep overbites ?
Early
Late mixed or early permanent dentitions best time (age 10 to 13 years)
The diagnosis of a Class II Div 2 malocclusion is based on
the incisor relationship
Definition of class II div 2
Lower incisor edges are palatal to the cingulum plateau of the upper incisors and the upper central incisors are retroclined.
The overjet is usually average but may be increased
Incidence of Class II div 2 incisor relationship ?
5-10 percent of population
Class II Div 2: extra-oral features
•Skeletal II
•Reduced lower face height
Class II Div 2: intra-oral features
. Retroclined upper (and lower incisors)
•Increased inter-incisal angle
•Deep overbite
Class II Div 2: Cephalometry upper incisors/ Mx angle
UI Retroclined UI/Mx < 105º
Skeletal relationship and ANB for Class II div 2?
Skeletal class II
ANB >4•
Class II Div 2
Overbite ?
Lower facial proportions ?
Increased overbite
Reduced lower facial proportions
Significance of Class II Div 2V
•Poor dental appearance
•Traumatic overbite
•Reduced lower face height
Treatment of II Div 2: Aims
. Relieve crowding and align arches
•Reduce overbite
•Produce a stable incisal relationship
•Improve facial profile
Treatment Options for class II div 2
•Fixed appliances
•Often also use URA to help overbite reduction
•Fixed Appliances + Surgery
Treatment II Div 2: Fixed appliances- how ?
•Root control required to upright and then bodily retract upper incisors
•This type of tooth movement is called “torqueing”
II Div 2: Fixed appliances: which cases?
•Crowded upper arch requiring extractions
•Crowded lower arch requiring extractions and alignment
•Acceptable facial profile
•Only in growing patients if there is a deep overbite
II Div 2: Fixed appliances- clinically how
•Anterior biteplane usually used with fixed appliances to reduce the overbite
•Usually extract upper 1st premolars
Class II Div 2: Fixed Appliances
Stage 1
Overbite reduction …
An upper removable biteplane and lower fixed appliance is an efficient way to reduce a deep overbite
Class II Div 2: Fixed Appliances
Stage 2 …
Torquing upper incisors
II Div 2: Surgery. Which cases?
•Adult patients (non-growing)
•too old for functional appliances
•Poor facial profile
•vertical: reduced lower face height
•AP: Class II skeletal pattern
•Deep overbite
II Div 2: Surgery
Correction of incisor inclinations
using fixed appliances
Surgical correction of jaw relationship
Prognosis, Retention and Stability of Class II Div 2
Stability depends on …
Must achieve …
•Stability depends on correction
of the inter-incisor angulation
Must achieve Class I incisors
How to ensure good prognosis retention and stability for Class II div 2
Usually a lower fixed retainer
Class II div 2 (increased overbite)
Treatment is ?
What is important ?
What is often required ?
Difficult
Overbite reduction
Fixed appliances
Class II div 2: who may require surgery ?
Severe skeletal discrepancies or non-growing patients
When to refer patients for II/2 ?
Refer patients early (late mixed or early permanent dentition). Age 10-11
