Bite Plates

Definition

Biteplate is an appliance widely used in orthodontic treatment for many purposes. It can be removable (can be taken out of the mouth by the patient) or fixed (cemented in the mouth and removed only at the end of treatment by the dentist).

Types

In orthodontics there are 2 types of biteplates:
1) Anterior biteplates
2) Posterior biteplates

Note: In the vast majority of circumstances, biteplate refers to the anterior biteplate rather than the posterior biteplate due to its more frequent use

The general use of biteplates
1) Opening the bite
2) Disocclude teeth

Biteplates can be used to correct dental or functional malocclusions such as:

a. Selective disocclusions
b. Occlusal adjustments
c. Diminished vertical dimension
d. Irregular occlusal plane
e. Severe deep overbite (upper front teeth covering much of the lower front teeth when biting)
f. Posterior bite collapse (due to breakdown; often causing flaring of anterior teeth)
g. Open bite (gap between lower and upper front teeth when biting)
h. Class II division I (upper front teeth are too far forward)
i. Functional Crossbite
Bite planes free occlusal interferences for quicker tooth movement or to allow some teeth to erupt while holding others in their position (the posterior bite plane allows the anterior teeth to erupt while the anterior bite plane allows the posterior teeth to erupt)

Note.: Anterior or posterior biteplates are not functional appliances but they can be used in conjunction with Hawley type retainers, rapid palatal expanders, or activators.

Anterior biteplates

An anterior biteplate is an appliance that would fit snuggly to the palate of the patient (roof of the mouth) and disarticulates the front teeth (stops the upper and lower front teeth from touching each other). The appliance is retained in the mouth with the help of the clasps found in the appliance. Adams clasps around the molars and ball clasps in the space between teeth are most commonly used for this purpose of retention.

Components:

1. Palatal acrylic coverage and anterior baseplate
2. Adams clasps for retention
3. Hawley type labial bow for anterior stabilization (optional)

Note: a C-clasp may be used instead of an Adams clasp if the Adams clasp is found to interfere with the occlusion.

Indications

An anterior biteplate is most commonly used to correct a deep bite (when the upper front teeth greatly overlap the lower front teeth). Such cases render orthodontic treatment harder to deliver: deep bite combined with low overjet (upper front teeth sliding too close against the lower front teeth) leads to shearing off of lower brackets. Deep overbite also hinders the anterior-posterior movement of teeth (teeth moving forward and backward), leading to delays in response to orthodontic dental treatment.

Its main function is to disocclude posterior teeth with relative intrusion of anterior teeth to allow for:
1. Correction of deep bite by extrusion of posterior teeth and relative intrusion of anterior teeth
2. Correction of posterior crossbite of dental origin
3. Eliminate adverse forces of occlusion
4. Eliminate occlusal interference to facilitate tooth movement
5. Correction of some temporal mandibular disease when use in combination with fixed appliance
6. Correction of a Class II div. I. Used as a functional appliance, it causes the disarticulation of the posterior teeth and forces the mandible to bite in a more forward position

The disarticulation of the front teeth by the biteplate opens a space in the back of the mouth between the posterior teeth as shown in the picture (Fig3) The space now existing between the upper and lower teeth (the posterior ones) encourages them to erupt further. This is due to the fact that teeth keep growing until they come against resistance. The eruption of the posterior teeth will decrease the overbite (amount of lower front teeth covered/overlapped by upper front teeth when biting).

Contraindications:
♦ Incompliant patient
♦ High caries risk
♦ Poor oral hygiene
♦ Patient with long lower face height

Posterior biteplates

Same concept as an anterior biteplate except it comes between upper and lower posterior teeth, causing an amount of space to be available between the upper and lower anterior teeth. This in turn would allow the anterior teeth to erupt.

Indications

1. A posterior biteplate is used to correct an anterior open bite (when front teeth are not overlapping at all when biting). It is often used with a functional appliance such as an activator. It does so by allowing the anterior teeth to erupt (extrude) while preventing the posterior teeth from erupting (some relative intrusion of the posterior teeth).

2. It may be used in conjunction with an appliance to expand the palate (roof of the mouth) to correct a functional crossbite.

3. May also be used to correct a Class I type III (lingually trapped anterior tooth). It does so by opening the bite hence allowing the trapped tooth to come into occlusion.

Requirements of a posterior biteplate:

1) It should be thin.
2) Occlusion should be adjusted equally on both sides (both sides should touch at the same time)

Contraindication:

1) Uncooperative patient
2) Poor oral hygiene
3) High caries rate
4) Class III of skeletal origin (lower jaw is too far forward)

Timing

♦ Biteplates can be used at any age. When used as a functional appliance, the biteplate is best used while growth is still occurring (i.e. in the mixed dentition phase). For treatment of dental malocclusions, it can be used in the mixed or permanent dentitions.

♦ Intrusion/extrusion of teeth (i.e. correction of a deep overbite) takes several months during which time the appliance must be worn on a full-time basis. Once the proper vertical dimension has been established, the biteplate must be worn as a retainer at night for a Maintenance phase (due to a strong tendency for relapse)

Special Consideration:

♦ High FMA (Frankfort mandibular plane angle)
There is a great tendency for an anterior open bite to occur. Anterior Biteplate therapy with these cases is not indicated, however a posterior bite plane may be used

Adjustments
♦ Tightening of clasps with birdsbeak pliers or three-prong pliers
♦ Activation of the spring 1mm at a time (if used)
♦ Removal of material from baseplate (pink material) to allow activation of a spring (if used in the appliance) but not near a clasp as this may jeopardize retention on the anchor teeth

Directions for wearing:

a) Active treatment
♦ All the time (except meal time, contact sports)

b) Retention
♦ Wear at night time only for 6 months

Variations in biteplate

♦ Fingerspring, microscrews etc can be added (used to tip certain teeth while the biteplate is in the mouth)
♦ Can be used in combination with other appliances (e.g. fixed appliances, headgear)

Maintenance

♦ Patient should clean the appliance on a daily basis with their toothbrush, some toothpaste and cold water.
♦ Hot water should be avoided as it might distort the acrylic (the pink material) which leads to improper fitting of the appliance.