DEPROGRAMMING SPLINTS

By- DR. ARPIT RAMANI

NPDCH

WHAT ARE SPLINTS?

Occlusal Splint/ Occlusal Device/ Orthotics: “Any removable artificial occlusal surface used for diagnosis or therapy affecting the relationship of the mandible to the maxillae. It may be used for occlusal stabilization, for treatment of TMJ disorders, or to prevent wear of the dentition.”

Its usually made of hard acrylic, that fits over the occlusal and incisal surfaces of teeth in one arch, creating precise occlusal contact with the teeth of opposing arch

Splint therapy may be defined as the art and science of

establishing neuromuscular harmony in the masticatory system

and creating a mechanical disadvantage for parafunctional

forces with removable appliances.

A properly constructed splint supports a harmonious

relation among the muscles of mastication, disk assemblies,

joints, ligaments, bones, teeth, and tendons

Principle:

Most occlusal splints have one primary function: to alter an occlusion so they do not interfere with complete seating of the condyles in centric relation.

When and why are splints(orthotics) indicated? Stabilization of weak teeth: An occlusal splint can effectively stabilize weak or

hypermobile teeth by the adaptation of the splint material around the axial surfaces.

In stabilizing the occlusion in patients with anterior open bites and other

malocclusions Distribution of occlusal forces Reduction of wear Stabilization of unopposed teeth Alteration of the dental occlusion Reduction of muscle contraction and associated forces Repositioning of the TMJ Splints are effective in reducing musculoskeletal pain (myalgia, myofascial Pain,

osteoarthritis and systemic arthritis (RA).

- Splints allowing the condyle to seat in centric relation

What is CR – GPT “A clinically determined relationship of the mandible to the maxilla when the condyle disk assemblies are positioned in their most superior position in the mandibular fossae and against the distal slope of the articular eminence”

Occlusion hit and slide can create muscle incoordination when occluding.

How do muscle and joint disorders affect occlusal stability and Centric Relation?

- All joints, including the temporomandibular joints, undergo remodeling throughout life with thinning of the disc and remodeling(flattening) of the head of the condyle and articular eminence.

As the disc space diminishes, the elevator muscles continue to seat the condyle in the fossa resulting in greater wear of the posterior molars.

In patients with oral habits of clenching and bruxing, a progression of excessive occlusal wear, excessive interproximal wear, crowding of the mandibular teeth will be seen. With interproximal wear, the arch shortens and a malocclusion may result and even an anterior open-bite relation.

- Sustained muscle contraction in clenching and bruxing can lead to muscle co-contraction and a shortened resting muscle length.

- Chronic and acute overloading of the condyle/disk assembly when it is out of its normal physiologic position contributes greatly to the catch-all term temporomandibular disorder. Temporomandibular joints are load bearing and susceptible to overload.

The key rule is, “do not adjust the occlusal of the teeth in any patient with muscle pain or muscle or TMJ dysfunction.” “Resolve the muscle and joint pain first with a splint or other reversible procedure or modality,e.g.stress management, and then reevalualte the occlusion.”

Centric relation is the optimal arrangement of joint, disk, and muscle.

HISTORY OF SPLINTSWith the development and patenting of vulcanite rubber in 1855, Charles Goodyear provided dentists with material that could be molded for many different oral appliances.

In November 1862, Thomas Gunning , a practicing surgeon, used vulcanite to fabricate a custom fitting splint to treat himself for a broken jaw.

The Gunning vulcanite splint, is remarkably similar to appliances used today to treat TMD. Additionally, his double arch splint, very closely resembles early orthodontic positioners, snoring and sleep apnea appliances in use today.

In 1887, twenty five yrs. after Gunning’s development, Kingsley, published an article discussing the use of soft vulcanized rubber to make an obturator.

Karolyi, a German, introduced an occlusal splint in 1901 for the treatment of bruxism.

Hawley, in 1919, and then Monson, in 1921, each suggested that bruxism led to a loss of occlusal vertical dimension, which gave rise to occlusal disorders

SPLINT TYPES AND FUNCTIONS According to Dawson:

1. Permissive splints/ muscle deprogrammer : (eg.-ant deprogrammer,ant jigs, lucia jig, stabilization splints)

2. Directive splints/ non-permissive splints: --(eg-ant repositioning splints)

3. Pseudo permissive splints (e.g Soft splints, Hydrostatic splint)

MORA – mandibular orthopedic repositioning appliance

Permissive Splints:

They are designed to eliminate noxious occlusal contacts and promote

harmonious masticatory muscle function. The primary function of these splints is

to alter the occlusion so that teeth do not interfere with complete seating of the

condyles and to control muscle forces. These represent the flat-plane appliances.

The two classic designs of permissive splints are anterior midpoint contact

splints and full contact splints.

Directive splints (Pull forward splint or Anterior Repositioning Splint)

These Are designed to position the mandible in a specific relationship to the

maxilla. The sole purpose of a directive splint is to position or align the condyle-

disk assemblies. Thus directive splints should be used only when a specifically

directed position of the condyles is required

PERMISSIVE SPLINTS/ MUSCLE DEPROGRAMMER

The concept of deprogramming is based on the reflexive relaxation of the lower jaw when the posterior teeth are not permitted to engage.  The various muscles that open and close the jaw learn and remember the level of contraction needed to perform their movements in a coordinated, comfortable way.

They learn which positions of these muscles cause pain, and which don't, and store all the information in your brain in the form of "engrams" which are similar to automatic, unconscious computer programs that our body uses each time we open or close our mouth.  In persons with TMJ, these movements can be quite complex

The relief of symptoms is the result of a forced relaxation of

the muscles of mastication, which in turn brings about relief of

pressure on all anatomic structures including the TMJ, the muscles of

mastication, the teeth and supporting structures. 

Deprogramming frequently brings about a shift in the position of the

lower jaw leaving the joints in a more relaxed functional position which

probably corresponds fairly closely to Dawson's definition of centric

relation.  The condyles thus occupy a more centric and relaxed position

in the fossae.  This position is reproducible without forceful manipulation

by the dentist. 

ANTERIOR MIDPOINT CONTACT PERMISSIVE SPLINT

Anterior midpoint contact permissive splints are designed to disengage all teeth except the incisors. This accomplishes several objectives:

-- It removes occlusal interferences to complete joint seating on closure.

-- Simultaneously, it allows freedom for full seating of the mandibular condyles when the elevator muscles contract on closure.

-- It encourages release of the lateral pterygoid and anterior neck positioning muscles on closure.

It has been shown through electromyography that molar contact allows 100% clenching force; cuspid contact permits approximately 60% maximum clenching force; and incisor contact minimizes elevator muscle clenching force to 20% to 30% of maximum clenching force.

Therefore, muscle clenching forces are reduced significantly when contact is isolated exclusively on the incisors. The width of the midpoint contacting platform is limited to the width of the 2 lower incisors, measuring 8 mm to 10 mm.

Eliminating posterior teeth contact significantly reduces noxious sensory feedback, through the trigeminal afferents, from previously sore temporalis muscles, which can evoke sympathetic vascular changes intracranially. This is the premise of the nociceptive trigeminal inhibition (NTI) splint

NTI (nociceptive trigeminal inhibition) anterior midpoint contact permissive splint.

-- Other examples of anterior midpoint contact permissive splints include the Lucia jig (Great Lakes Orthodontics, LTD, Tonawanda, NY) and the B splint.

Lucia jig anterior midpoint contact permissive splint.

B Splint (bruxism) anterior midpoint contact permissive splint.

Lower full arch permissivesplint.

Upper full arch permissivesplint.

Gibbs et al found that the highest recorded bite force during bruxism was 975 lbs. and that can be as much as 6 times to that of the nonbruxer. The average maximum biting force measured during clenching is 162 lbs. This data indicates why the forces generated during night activity can destroy the dentition. A splint not balanced in CR will show increased localized wear.

Holmgren et al have shown that splints do not stop bruxism but do redistribute the load borne by the teeth and masticatory system.

Piper recommended using a 12- to 15-mm-thick splint (incise edge to incisal edge) to decrease clenching efficiency. A thick splint should be considered for chronic bruxers with morning muscle pains.

Thick splint used to decrease muscle strength duringbruxism.

Anterior Deprogrammer type splints

“Do not use them if the patient continues to clench and or grind on the anterior deprogrammer type appliance and scratches are seen on the appliances.” “This will cause injury to the TMJs.” “If a patient continues to clench on an anterior bite plane, the biting forces will be directed onto the disc causing injury.

Why Deprogram? An anterior midline contact produces minimal temporalis contraction intensity and minimal joint strain, and tends to allow the TMJ to translate slightly forward to rest against the eminence. 

Thus deprogramming is a simple trick to produce a forced relaxation of the temporalis, masseter and pterygoid muscles allowing the TM Joints to rest in a functionally comfortable position in the fossa. 

Masseter and Temporalis are the key players in the action of mastication. Muscular activity is independent of the occlusal scheme. However, the occlusal scheme modifies the forces generated by the muscular activity

The best application of the occlusal splint seems to be in its application prior to any occlusal adjustment. It is important to bring the patient to ‘round zero’ lowering EMG activity in the masster and temporalis muscles, and then proceed with further treatment.

It is imperative to understand that results of splint therapy are temporary and recurrent symptoms are likely to show up within 4 wks of discontinuing the splint.

The deprogrammer, followed by a bruxing guard built using the new functional (deprogrammed) bite registration can bring about immediate and permanent relief of pain in a majority of TMD cases. 

Symptoms relieved include a reduction in tension headaches, ear aches and the neck stiffness associated with parafunction.  Sensitive teeth and "phantom toothaches" in otherwise healthy teeth frequently respond to this form of treatment.  Crepitus and popping of the temperomandibular joints may be lessened or relieved.

The deprogrammer accomplishes three goals

1. The deprogrammer brings about nearly immediate relief of

acute symptoms.  In general, pain is reduced or eliminated

within one or two hours of insertion of the deprogrammer. 

• Muscle relaxants, analgesics or other drugs are generally

not necessary

2. The butterfly deprogrammer helps to confirm the

diagnosis of TMD, and the appropriateness of jaw

repositioning as a treatment. 

In cases where the deprogrammer does not bring about

sufficient relief from pain, the construction of a functional

appliance will be of little benefit.  

Butterfly Deprogrammer

3.The butterfly deprogrammer brings about relaxation of masticatory structures, and allows for the determination of a functional centric jaw relation and the construction of a "deprogrammed" bite appliance. 

Any symptoms of TMD that have been relieved by the use of the deprogrammer should be also be corrected by a properly fabricated deprogrammed bruxing guard.

  Unfortunately, bruxing guards, even deprogrammed guards, do not always relieve tension headaches since the patient can still clench against the guard.   Even so, patients often experience a reduction in the frequency and intensity of tension headaches.

Dr. N.R. Krishnaswamy (7th IOS P.G. Convention) outlined the objectives of Splint therapy as follows

•To find the “true” anatomic relationship of the mandible to the maxilla by “deprogramming” the muscle to eliminate the neuromuscular reflexes.

•To test the patient’s response to a change in the occlusion

•To determine if the craniomandible relationship can be stabilized.

ANTERIOR DEPROGRAMMER FABRICATION TECHNIQUE

Prepare the model Place a sheet of Isofolan spacer in place of separating medium

Position the model in the pellets Enter the heating time of 25 seconds into the Biostar

after heating cycle is complete, swing thechamber over the model. Lock the chamber to activate the pressure and the cooling cycle

At the end of the cooling phase, evacuate the air pressure from the chamber and Slide the clamping frame to the left to release the material and swing the chamberback to its open position.

Trim the excess materiala piece of 1.5mm splint Biocryl material is used to fabricate an anteriordeprogrammer

Place the material on the pressure chamber Enter the heating time of 50 seconds into the Biostar

Once the heating cycle is complete, swing thechamber over the model

Remove the matrix from the machine and shake offexcess pellets.

Trim excess material With a lab knife, remove the splint Biocryl from the model. Peel away and discard the Isofolan spacer.

Place the trim-line at

With a carbide taper bur in a lab handpiece, trim the Biocryl to the reference lines

halfway down the labial surface of the anterior teeth and at the gingival margin of the labial surface of the posterior teeth.

Direct Technique

For the direct technique, try the Biocryl matrix on the patient to make sure it’s comfortable

With 50 micron aluminum oxide, air-abraide the anterior section from the first premolar to the first pre-molar where the bite plane will be formed

Apply a light cure bonding agent to the anterior section cure it according to the instructions for the bonding agent.

Light-cure rope material is used to form the bite plane. With fingers, mold the light cure material to the basic flat plane form from first pre-molar to first pre-molar. The bonding agent can be used to smooth the bite plane to reduce trimming time.

Prepare a Whale Tail with a thin layer of petroleum jelly. This will be used to form the flat plane. Place the appliance into the patient’s mouth and slide the Whale Tailacross the bite plane

Ask the patient to close very lightly into the bite plane so that the lower six anterior teeth just come in contact with the bite plane.

Use a light cure gun to cure the bite plane With a pencil, mark where the lower anteriors made contact with the bite plane.

The goal is to trim the bite plane as flat as possible Insert the appliance in the patient’s mouth. Use blue or black articulating paper tocheck the contacts.

If all anterior teeth are not contacting the bite plane, lightly trim marks and repeat theprocess until all anterior teeth are in contact

Once all the anterior contacts are visible, choose a different color articulating paper to mark excursive movements

After excursive movements are marked, use the black or blue articulating paper to mark the centric contacts

Remove the appliance. Check to ensure contacts trimming and finishing procedures

Finished Anterior Deprogrammer

CHOOSING THE CORRECT SPLINT Determination of the appropriate type of splint therapy depends on the specific diagnosis of the temporomandibular disorder and a thorough understanding of the anatomy of the condyle/disk complex.

Muscle incoordination is determined by muscle palpation, joint loading, range-of-motion measurements, joint palpation, occlusal evaluation, and Doppler diagnosis.

Patients present with painful symptoms in the facial muscles, headaches, limited ranges of motion, frequent joint inflammation, and occlusal interferences to CR; infrequent clicking on jaw movement also may be present.

This anatomic asymmetryis reversible if caught in time and treated with bite plane therapy or permissive splint therapy in Phase I (reversible treatment) and with appropriate Phase II therapy (additive or subtractive occlusal therapy, restorative dentistry, orthodontics, maxillofacial surgery, and segmental alveolar surgery) to restore balance from/to the CR position.

Muscle and disk incoordination has the same signs and symptoms as muscle incoordination except reciprocal clicking or a history of reciprocal clicking that stops. Diagnosis may include sagittally corrected tomograms. Patients often present with the medial pole of the condyle intact under the disk with the lateral pole of the disk damaged from loading or stretching and subsequent ligament laxity.

Most symptoms may be reversible if caught in time, though the reversibility of clicking depends on the shape of the distorted disk and the fibrosis of the lateral pterygoid muscle.

Treatment usually includes permissive splint therapy and Phase II therapy for stabilization because of the weak ligament structure.

With advanced muscle and disk incoordination, symptoms may be the same as in previous stages, though jaw locking, painful joint noises, and increases in pain with splint therapy may be evident. These patients often have a long history of joint noises without pain that have become painful. Pain on loading with bimanual manipulation is evident and may be extreme.

Diagnostic techniques include sagittally corrected tomograms and magnetic resonance images. Surgical intervention may be necessary depending on the location and degree of displacement of the disk.

These stages are irreversible but may be managed to a pain-free state with appropriate medications, splint therapy, and Phase II therapy.

REFERENCES 1) INTERNATIONAL JOURNAL OF DENTAL CLINICS: 2 (2):22-29

2) J Appl Oral Sci 2004; 12(3): 238-43

3) Anterior Deprogrammer Fabrication Technique

4) DeWitt C. Wilkerson, DMD Senior Faculty/Lecturer, Dawson Academy Adjunct Professor, University of Florida College of DentistryPartner, International Center for Complete Dentistry, St. Petersburg, Florida.

5) J Adv Prosthodont 2014;6:103-8

6) J tnd Orthod Soc 2002; 35:113·117

7) J Prsthet Dent 2001;86:539-45.