Deep Bite Management
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Direct answer
Overbite that traps the lower incisors against the palate or upper incisors against the labial gingiva — beyond about 3 mm of vertical overlap, or covering more than two-thirds of the lower crowns — is a deep bite, and its first subdivision is therapeutic: a true deep bite combines excessive overlap with a reduced lower anterior face height (the Class II division 2 prototype), while a pseudo deep bite deepens secondarily to attrition with a normal face height, and requires restoration of the lost vertical dimension rather than pure intrusion. Correction then proceeds by three levers chosen for growth status and facial pattern — molar extrusion in growers with flat-to-normal mandibular planes, true incisor intrusion with utility or intrusion arches (or miniscrews) in adults and high-angle faces, and Le Fort I impaction with autorotation where vertical maxillary excess drives the trait — closed by retention with a bite-plane retainer, since deep bite is among the most relapse-prone of corrections.
What you must remember
- Definitions: normal overbite 2-3 mm or one-third to one-half of the lower crown; a complete deep bite contacts palatal mucosa or gingiva and constitutes traumatic occlusion demanding priority.
- True deep bite: reduced lower anterior face height, Class II tendency, excessive curve of Spee, deep mentolabial fold; pseudo deep bite: normal face height, generalised attrition, deepened by wear.
- Three-component analysis: over-erupted incisors, excessive curve of Spee, under-erupted molars — each dictates one lever of mechanics.
- Growing patients: anterior bite planes disocclude the posteriors so molars erupt and the mandible rotates forward — extrusive levelling is appropriate only in low to normal angle, growing faces.
- Incisor intrusion: Ricketts' utility arch bypassing the buccal segments to intrude and torque the incisors with light force (15-20 g per incisor region); Burstone's intrusion arch with an auxiliary to the segment; Begg mechanics use anchor bends on 0.016 round Australian wire to intrude incisors as an anchorage consequence.
- Adults and high-angle faces: extrusion relapses and lengthens the face — intrude with miniscrews or accept surgical impaction for vertical maxillary excess.
- Trauma hierarchy: palatal stripping and lower labial gingival trauma from incisal edges prioritise deep-bite correction in sequencing.
- Retention: Hawley-type retainer with a flat anterior bite plane worn nights, because both extrusion and intrusion relapse without it.
Correcting a division 2 deep bite
A 14-year-old girl presents with a Class II division 2 malocclusion: overbite 7 mm, lower incisors striking palatal mucosa with a localised gingival furrow, deep curve of Spee, and a horizontal growth pattern — still growing, which is her greatest asset. Step one relieves the trauma: a removable anterior bite plane worn full-time disoccludes the posteriors, allowing mandibular development while the appliance plan is made. Step two aligns and corrects torque: division 2 mechanics begin with alignment on light wires, then deliberate labial root torque of the retroclined upper incisors — the bite often deepens transiently as incisors upright. Step three levels the curve of Spee to her facial pattern: in a horizontal grower, a bite-plane effect within the fixed appliance lets molars erupt and the curve flattens extrusively; where intrusion is chosen, a utility arch delivers 15-20 g of true incisor intrusion while the molars remain untouched. Step four addresses the Class II sagittal discrepancy — functional appliance or headgear as growth permits. Step five retains with a deep-bite retainer carrying a bite plane and reviews the traumatized palatal mucosa, which recovers once the trauma is removed. Contrast her 26-year-old sister: no growth remains, extrusion would rotate the mandible down and back, and her plan leans on miniscrew intrusion or Le Fort I impaction.
Where students slip
The pattern error is extruding molars in every deep bite: in the adult or high-angle face, extrusion lengthens the face, rotates the mandible backward and relapses — name the facial pattern before naming the wire. The second slip is forgetting that straight-wire levelling of a deep curve of Spee itself extrudes incisors; genuine intrusion requires utility, intrusion-arch or screw mechanics, not passive hope. The third is definitional: offering intrusion to an attritive pseudo deep bite mistakes the problem — lost tooth structure — and restoration is the actual treatment.
Frequently asked questions
What distinguishes true from pseudo deep bite?
True deep bite has a reduced lower anterior face height with genuine vertical overlap excess; pseudo deep bite has a normal face height with the bite deepened secondarily by attrition.
How does an anterior bite plane correct deep bite?
It disoccludes the posterior teeth, permitting molar eruption and forward mandibular rotation in a growing patient — the effect is extrusive levelling, appropriate only in growing, low to normal angle faces.
Who designed the utility arch and what does it do?
Ricketts; a bypass arch from the molars to the incisors delivering true incisor intrusion with torque at light force, leaving the buccal segments untouched.
Why is molar extrusion avoided in adults?
Without growth, extrusion relapses, rotates the mandible down and back, lengthens the face and worsens the profile — intrusion or surgery is the stable route.