The Bionator appliance was developed by Dr. Wilhelm Balter in post war Germany. Dr. Balter redesigned the classic activator appliance which had been used in Europe since the early 1900’s to treat skeletal Class II patients. The Bionator appliance was less bulky and easier for the patient to tolerate than the activator appliance.

There are two basic designs of the Bionator appliance. They are the Bionator to open the bite and the Bionator to close the bite. The Bionator to open the bite has an anterior cap that allows for the eruption of the posterior teeth. The Bionator to close the bite has posterior occlusal coverage of acrylic which has a bite closing effect. Both of the designs can also distract the trapped retrognathic skeletal Class II mandible into a skeletal Class I relationship in the pre pubertal patient. (See fig. #1)

Bionaroe to Open Bionator to Close

Fig. #1

Some clinicians like to modify the Bionator appliances with Adams clasps on the maxillary first molars. This modification stabilizes the appliance on the upper arch making it easier for the patient to adapt to the appliance. The Adams clasp is removed for eruption of the upper molars. (See fig.#2)

Fig.#2

Bionator therapy is always preceeded by eleminating the maxillary entrapment that was the cause of the trapped retrognathic mandible. This is usually accomplished by developing the maxilla with one of the designs of the maxillary Schwarz appliance. The Schwarz appliance can be used in conjunction with the night reverse pull gead gear if the position of the maxilla is also retrognathic. (See fig. #3)

Fig.#3

The Bionator is one of many demand position appliances. What makes the appliance unique is it is both an upper and lower appliance combined into one. (See fig.#4)

Fig.#4

Bight Registrations for the Bionator

As with any demand position appliance the patient must have both mandibular codyles correctly positioned on the biconcave articular disks when the bite registration is made. This means that the patient must open as wide as possible prior to making the registration. The patient should be positioned vertically for the registration.

If the patient is a Skenetal Class II deep bite the mandible is moved forward into an end to end relation of the incisors with 2mm vertically between the incisors. The skeletal midlines are correctly aligned. A bite jig is used to hold the mandible in this demand position. Registration paste is used to record the demand position bite. If the patient is a skeletal Class I deep bite the positioning of the mandible is the same and the thickness between the incisors is increased to 4mm. (See fig.#5)

Class II Deep Bite Class I Deep Bite

Fig. #5

If the patient is a skeletal Class II open bite the forward positioning of the mandible remains the same as in the closed bite patient. The vertical dimension must now be opened sufficiently to create around 1.5mm clearance between the most posterior teeth in occlusion. This creates space for the posterior occlusion coverage of acrylic in the appliance. The bite jig is still used by either adding sufficient compound to create the posterior clearance, or by selecting a new thicker bite jig.(See fig.#6)

F

Fig.#6

Horizontal Forces in the Bionator Appliance

Any distraction appliance initially has horizontal forces within the appliance created by the muscles of mastication. The greater the mandibular distraction the higher the level of this horizontal force. This force remains active for approximately the first 90 days of treatment. (See fig.#7)

Fig. #7

This horizontal force in the Bionator appliance must be anchored to prevent it from forcing the lower incisors into excess proclination and from distalizing the maxillary buccal segments. This anchorage must be maintained for approximately 90 days until the muscle attachments begin to migrate and the horizontal force becomes passive. (See fig.#8)

Fig. #8

Insertion Adjustments For Bionator To Open

The first step in placing the Bionator to open the bite is to have the patient fully open their mouth to insure the mandibular condyles arecorrectly positioned on the articular disks. If the patient cannot occlude in the appliance the origional construction registration was made with the mandibular condyles off of the disks. If this occurs a new registration is made and the Bionator is reset to the new registration.

The insertion adjustment for the upper portion of the Bionator is to place the labia bow into the gingival one third of the maxillary incisors to engage maxillary cross-arch anchorage. The adjustment is made symmetrically with the 3-Jaw pliers on the superior and inferior loops in the Hawley labial bow. This prevents the appliance from distalizing the maxillary buccal segments. (See fig.#9)

Fig.#9

The insertion adjust for the lower portion of the appliance is to releive all acrylic contacting the lingual surface of the lower incisors. This adjustment isolates the horizonal force on the lower buccal segments engaging mandibular cross-arch anchorage. This prevents the lower incisors from being dumped forward into excess proclanition. (See fig.#10)

Fig.#10

No further adjustmentis are made on the appliance for 90 days to allow the horizontal forces created by the muscle to become passive. The clinician should monitor the inclination of the lower incisors every four weeks. If the lower incisors begin to move into excess proclination the lingual acrylic of the lower portion of the appliance has moved back into contact and needs to immediately be releived. This is caused by the cranial sutures responding the the mandibular distraction. (See fig.#11)

Fig.#11

The patient should wear the Bionator full time with the exception of eating and for heigyne. Reduced weartime increases the treatment time with the Bionator. The patient acquires approximately 80% of their growth while sleeping so night time wearing is manditory for the appliance to be effective.

After the initial 90 days of treatment the Bionator appliance is adjusted to to allow the posterior teeth to erupt which will open the deep bite. The tooth surface of the appliance is not polished. After 90 days the posterior teeth create a shiney area on the dull acrylic indicating their heights of contour. These shiney facets are used as a guide for adjusting the acrylic. If the patient is a skeletal Class II deepbite the posterior acrylic is releived to allow the lower teeth to erupt. If the patient is a skeletal Class I deep bite the posterior acrylic is releived to allow both the upper and lower posterior teeth to erupt.(See fig.#12)

Fig. #12

After the posterior acrylic has been correctly adjusted the clinician needs to chech the inter proximal molar contacts in the arch or arches that are going to erupt. If the contacts are tight separating elastics are placed which allows the molars to erupt. (See fig.#13)

Fig.#13

The Binator can be fabricated with a midline screw at the lower intercanine area. After the first 90 days of therapy the screw is adjusted twice a week to insure the lower inter canine width is fully keystoned. (See fig.#14)

Fig.#14

When the screw in the Bionator is turned it causes the Hawley labial bow to retract. The bow must be advanced to prevent the creation of a dental Division Two. The adjustments are made symetrically with a flat on flat plier on the superior and inferior loops of the bow. (See fig.#15)

Fig.#15

 

The skeletal Class II correction usually occurs prior to the eruption of the posterior teeth which opens the deep bite. The point to understand is even though the Bionator is still holding the mandible in the distracted position, horizontal growth terminates when the mandible attaines its genetic potential. There is a period of time where the patient only occludes on their anterior teeth. This is not an issue with the younger patient as the articular disks are still dense fibrous tissue and do not require poaterior vertical stops in the occlusion to function normally. The Bionator must continue to be worn until the posterior teeth erupt to support the correct anterior vertical dimension.(See fig.#16)

Fig.#16

The posterior vertical support will be on the permanent first molars. The support almost always occurs unilaterally due to the cant the maxilla which is a conponent of the origional skeletal malocclusion. Once the molar support is established the Bionator appiance is terminated. This allows function to level the maxillary plane as the cranial surures re-establish balance. (See fig#17)

Fig.#17

Retention

There is no retention for Bionator therapy to open the bite. Once the mandible has been distracted into the skeletal Class I relationship and there is posterior molar support established at the correct vertical dimension treatment is terminated. If the patient is still in the mixed dentition a lingual arch is placed to hold the lower Space of Nance as the patient matures into the permanent dentition.

Insertment Adjustments For The Bionator To Close The Bite

The first step in placing the Bionator to close the bite is to have the patient fully open their mouth to insure the mandibular condyles are correctly positioned on the articular disks. If the patient cannot occlude in the appliance the origional construction registration was made with the mandibular condyles off of the disks. If this occurs a new registration is made and the Bionator is reset to the new registration.

The insertion adjustment for the upper portion of the Bionator is to engage the labia bow into the gingival one third of the maxillary incisors to engage maxillary cross-arch anchorage. The adjustment is made symmetrically with the 3-Jaw pliers on the superior and inferior loops in the Hawley labial bow. This prevents the appliance from distalizing the maxillary buccal segments. (See fig.#18)

Fig.#18

The insertion adjust for the lower portion of the appliance is to releive all acrylic contacting the lingual surface of the lower incisors. This adjustment isolates the horizonal force on the lower buccal segments engaging mandibular cross-arch anchorage. This prevents the lower incisors from being dumped forward into excess proclanition. (See fig.#19)

Fig.#19

The lingual tongue wires on the appliance are positioned to prevent the tongue from thrusting forward. These lingual wires are actually ball clasps that allow the tongue to adapt to the wires. After four weeks the ball is removed from the tongue wires. The position of the tongue wires should be checked every four weeks and are adjusted with the Large Occulist Pliers.(See fig.#20)

Fig.#20

Tongue guarde are bonded to the palatal fo the four permanent maxillary incisors. This prevents the tongue from thrusting into the anterior open bite when the Bionator is not being worn. (See fig.#21)

Fig.#21

The myofunctional swallowing training for the anterior tongue thrust began with the Schwarz appliance which developed the maxilla prior to placing the Bionator. This myofunctional therapy should continue until the anterior tongue thrust has been completely corrected.

The Bionator to close the bite has a lower midline screw. The screw can be adjusted to fully develop the lower inter canine width which key stones the lower arch. The screw is turned once a week. (See fig.#22)

Fig.#22

Turning the screw in the Bionator causes the Hawley labial bow to retract which will create a dental Division Two. To prevent this from occurring the labial bow is advanced using the flat on flat plier. The adjustments are made symmetrically on first the superior loops followed by the inferior loops.(See fig.#23)

Fig. #23

The appliance needs to be worn full time with the exception of eating and for hygiene. The clinician will initially see a marked change in the anterior open bite. This is the result of the mandibular condyles and the articular disks returning to their correct relationship. The remainder of the bite closure is an intrusion of the posterior teeth, eruption of the anterior teeth, and a realigning of the cranial sutures.

There are no additional adjustments required for the Bionator to close other than to monitor the inclination of the lower incisors. Any additional proclination is an indication that the lingual acrylic has come back into contact and requires additional relief.

Retention

Once the patient is a skeletal Class I and the anterior open bite close, the Bionator to close is worn at night only for 90 days. The objective is to be sure that the anterior tongue thrust has been fully corrected. If the bite remains closed the Bionator is replaced with a lingual arch to hold the lower Space of Nance as the patient matures into the permanent dentition.

If the bite starts to re-open the patient is still thrusting. The patient should go back to full time wearing of the Bionator appliance and the myofunctional swallowing therapy started again.

The objective of the orthopedic treatment is to create a skeletal Class I, dental Division One, correct vertical with the patient swallowing correctly and breathing through the nose. (See fig.#24)

Fig.#24