OPENBITE

Zainab HajiRoll # 12Dept of Orthodontics

Roadmap

Definition

Classification

Causes

Management

definition Malocclusion in vertical plane.

A deviation in the vertical relationship of the maxillary and mandibular dental arches characterized by a definite lack of contact between opposing segments of teeth.” (Daniel  Subtelny, 1964). 

“Localized absence of occlusion while the remaining teeth are in occlusion” (Moyer’s).

classification

According to location:Anterior OB.Posterior OB.

According to cause:Dental or simple OB.Skeletal or complex OB.

Anterior OB: “Absence of contact between the maxillary and mandibular incisors at centric relation (Worms 1971).”Absence of vertical overlap of incisors.

Posterior OB: “Lack of contact between the posterior teeth when the teeth are in centric occlusion.”

Dental (Simple) OB: When the basal skeleton is normal and the open bite is confined to the teeth and alveolar processes.

Skeletal OB: Results from skeletal dysplasia, so severe that the alveolar processes cannot cope to maintain occlusal stops. 

causes

Dental openbite 1) Heredity Secondary to class III malocclussion.

2) Environmental

Mouth breathing change in mode of

respiration ,lowers the mandible and the tongue

supra-eruption of posterior teeth

downward and backward rotation of mandible

increased facial (ant) height.

Factors that cause mouth breathing-

Enlarged adenoids or tonsils. naso-pharyngeal deformities. Enlarged turbinates. Allergic rhinitis, nasal polyps,

etc.

digit sucking

Normal upto 4-5 years - Inadequate development of the

anterior alveolar process. - Incomplete eruption of the incisor

teeth

Accommodation of thumb

Lowered positioning of mandible

Alteration in vertical equilibrium Excessive eruption of posterior teeth

 

Tongue thrusting

defined as placement of the tongue tip forward between the incisors during swallowing”.

Transitional Displaced incisors

Trauma Failure of eruption

Iatrogenic

Expansio

n treatmen

t:

Excessive tipping of the buccal segments.Elongation of lingual cuspPremature contactsOpen Bite

Distalization:

Distalization of 6 l 6 Distal tipping Elongation of mesial cusps OpenBite (Great concern in vertical grower)

as a consequence of orthodontic therapy

Skeletal openbite

Jaw rotation during growth.

The palatal plane rotates downward posteriorly.

Mandible shows backward rotation with an increased in MPA

management

Diagnosis: Extraoral Intraoral Cephalogram

Treatment: Deciduous dentition

Mixed dentiton:-habit control-growth modulation

Habit control:

Dental Approach:

Gaining confidence of the patient

Education to the patient Reminder Therapy Reward Therapy Restriction Therapy: Appliance : Vestibular screen. Tongue crib

Bluegrass appliance

Growth modulation

Only if associated with long face syndrome.

I. HIGH PULL HEADGEAR TO THE MOLARS: Maintains the vertical position of the maxilla. Inhibits eruption of the maxillary posterior teeth.. Duration : 14 hours, putting the headgear right after dinner and

wearing it until next morning. Force : 350 – 450 gm / side (12 – 16 ounces). Drawback : It does not control the eruption of other teeth.

II. HIGH PULL HEADGEAR TO A MAXILLARY SPLINT: acrylic splint to which a face bow and HP headgear is attached. appears to have substantial maxillary skeletal and dental effect

with good vertical control. Unfortunately, this appliance allows mandibular posterior teeth to

erupt freely, and if this occurs, there may be neither redirection of growth for favorable upward and forward mandibular rotation. 

III. FUNCTIONAL APPLIANCES WITH BITE BLOCKS :The retraction force of headgear is replaced by the somewhat lesser “headgear effect” of the functional appliance with posterior bite block

Purpose: To inhibit eruption of posterior teeth and vertical

descent of the maxilla. When the mandibular is held in this position by the

appliance, the stretch of soft tissues (including but not limited to the muscles) exerts a vertical intrusive force in the posterior teeth.

In children with AOB the anterior teeth are allowed to erupt, which reduces the OB.

As this allows the mandible to position forward, horizontal growth of mandible can be encouraged. 

IV. HP HEADGEAR TO A FUNCTIONAL APPLIANCE WITH BITE BLOCKS:

Most effective approach in OB classII.HP headgear: Increases the control of maxillary growth. Allows the force to be delivered to the whole

maxilla Improves retention appliance. Produces force direction near the estimated center

of resistance of the maxilla.  The headgear tube – is incorporated in premolar

regions. Force = 250 – 500 /side

PROFFIT’S HIERARCHY AND RECOMMENDATION:

  High pull headgear to a maxillary

molars

High pull headgear to maxillary splint

Functional appliance with bite blocks

High pull headgear to a functional

appliance with bite blocks

Surgical management

Surgical Orthodontics is a term that refers to surgical procedures carried out as an adjunct to or in conjunction with orthodontic treatment.

Orthognathic surgery is a surgical procedure carried out along with orthodontic therapy to correct dento-facial deformities or severe orofacial disproportion involving the maxilla, the mandible or both in combination.

Surgical –skeletal OB

I. MAXILLARY SURGERY: LeeForte I down fracture of maxilla, or. Segmental maxillary osteotomy, and Combination.

II. MANDIBULAR SURGERY: 1. BSSO (BILATERAL SAGITTAL SPLIT

OSTEOTOMY)2. INVERTED ‘L’ OSTEOTOMY OF RAMUS

WITH RIF:III. SUPERIOR REPOSITIONING OF THE

CHIN BY A MANDIBULAR LOWER BORDER OSTEOTOMY

Surgical-dental OB

(AOB NOT RELATED TO LONG FACE):

There are 2 major possibilities:1-Deficient eruption of maxillary

incisor:*LeForte 1 osteotomy with or without anterior and posterior components.

*Maxillary anterior segmental osteotomy.

Cont…

2-AOB due to deficient eruption of mandibular incisors +excessive eruption of posterior teeth:*anterior subapical osteotomy*total submandibular sub-apical osteotomy

references

Worms F.W, Meskin L.H, Isaacson R.J., Open bite. AJO 1971; 59:589-95.

Klein: The Thumb sucking habit: Meaningful or Empty. AJO 1971.

Bishara. Clinical Biomechanics, Seminar Orthodontics; March

2001, Vol 7. No.1. Carano A., Machita W. A rapid molar intruder for `Non-

compliances treatment’ . JCO 2002 March; 8: 137-142. Iscan M.N. Akkaya Sevil and Koralp E. The effects of

the spring - loaded posterior bite-block on the maxillo-facial morphology. Eur J Orthod 1992; 14:54-60.