Recapturing the Dislocated Disk

SUMMARY

In early stages of forward disk dislocation, orthopedic treatment may be able to restore the disk to its proper position by resetting your lower jawbone (your mandible) forward just far enough to prevent your disk from dislocating. This process usually produces rapid and profound relief, because it suddenly stops the chronic bruising of the retrodiskal tissues which triggers the muscle tension.  In the first phase of treatment, a telescopic night appliance and a tight fitting inconspicuous day appliance reset your mandible forward just far enough to prevent the disk from dislocating. After the disk has been held in place for long enough to stabilize and a new therapeutic bite has been established on the daytime appliance, a second phase of treatment is necessary to transfer that new bite to your natural teeth and thereby free you from having to wear your daytime appliance. If this second phase of treatment is not completed, the disk dislocation will almost certainly recur.  However the second phase requires permanently changing the bite, which can involve significant dental work.  Therefore, if you are considering disk recapturing, the severity of the symptoms and the ability to relieve them with simple treatments (such as wearing a joint protective stabilization appliance during sleep) need to be weighed against the time and expense ultimately required for dental work to change your bite. 

 YOUR DISLOCATED DISK

When your mouth is closed, your disk is dislocated. It only goes back into place for about a second when you open wide enough to click, shift, or pop; and then it goes back out again as soon as you close.   Below is an illustration of the sequence of disk dislocation and relocation during opening and closing.

                                                     MOUTH FULLY CLOSED 

                                                        MOUTH FULLY OPEN

NATURAL PROGRESSION OF THE DISK DISLOCATION 

In most early stages of disk dislocation, the disk is dislocated when your mouth is closed, it goes back into place during the opening click or pop, and it stays in place until you close all the way again.  You can get it to stay in place by keeping your mandible forward (front teeth touching), because your condyles have not gone back far enough to dislocate the disk again. Then, as soon as you bite back into your regular bite with your back teeth touching, the disk will go back out again, and the next opening will be accompanied by the clicking or popping sound made by the disk going back into place.

Over time, anatomical changes make recapture progressively more difficult.  The dislocated disk may get deformed (flattened or balled up), which can make it difficult to stabilize in its recaptured position.  Also the ligaments attached to the dislocated disk get stretched out, so you have to open progressively wider for the opening click to occur, and you have to hold your mandible further forward to stop the clicking.  Eventually your mandible has to be held so far forward that recapture becomes impossible.  The transition from a dislocated disk that can be easily recaptured to a dislocated disk that is difficult or impossible to recapture usually takes a few years, but the rate of progression varies a great deal. Some disks that have only been dislocated for a week can no longer be recaptured, and some disks that have been dislocated for a decade can still be recaptured.   Also, disks that are dislocated sideways are more difficult to recapture.

IMAGING 

The only reliable way to determine the shape, condition, and direction of dislocation of the disk is with MRI.  When considering recapture, the images are taken with the mandible in its old natural bite (should show the disk dislocated) and then again with the mandible in the new proposed therapeutic position (should show the disk recaptured) so that both the pathology and the anatomical correction can be verified before the correction is undertaken. The mandible is supported in the new proposed therapeutic position by a mold of bite putty which Dr. Summer will make for you to bring to the MRI.  If the MRI confirms the disk recapture, we can use that bite putty during the fabrication of the disk recapturing appliances to assure that they hold your mandible in the same position which verified the recapture.

PHASE ONE TREATMENT

The goals of phase one treatment are to hold your disk in its proper place while it stabilizes there and while we establish and test the new therapeutic bite which can be later used for finishing.  During this initial phase of treatment, the disk is held in place by a combination of day and night appliances.  The daytime appliance usually consists of two separate tightly fitting right and left side pieces with no midline plastic to impede normal speech. The night appliance is much more substantial, because it must provide absolute protection for the TMJs during nocturnal clenching and grinding when the jaw undergoes great pressure. One appliance or the other must be worn at all times. Taking the daytime appliance out to eat or sleeping without the night appliance would be like taking the cast off a dislocated knee to run around the block.

As soon as you begin wearing the appliances, you should be able to open your mouth full wide anytime day or night without hearing the click or pop that was previously caused by the disk going back into place. At the same time, your TMJ disorder symptoms should diminish rapidly. If you still hear any of the previous clicking or popping noises or if you don’t feel dramatic relief within a week, you should call the office right away, because the disk recapturing treatment is probably not working, and we should change to "off the disk" treatment as explained in MANAGING THE ARTHRITIC TMJ.

Keeping the disk in its recaptured position progressively stabilizes it and thereby diminishes the need to protect the old bite from returning.  During the first few weeks, the disk can redislocate again relatively easily if the appliances are not worn faithfully.  After the disk has been in place continuously for months, it usually stabilizes due to tissue adaptation.  Subsequently, your day appliance won’t need all its steep inclines, and they can be reduced. Shallowing the inclines makes chewing easier, but it should be done gradually - in a few appointments spread out over a couple of months.

A few recaptured disks stabilize slowly and could become dislocated again from a single mistake like falling asleep with the day appliance or receiving a minor blow to the jaw.  It is difficult to identify in advance which people will have slowly stabilizing disks.  If you notice an occasional click or any other indications that you are not stabilizing as quickly as normal, finishing should be delayed or reconsidered.

Even if the recapture fails, the symptom relief often lasts. When disk recapturing first became popular and the finishing (phase two) process was poorly understood in the 1980’s, there were many patients who underwent a successful phase one and then started clicking again during or shortly after phase two, but only about half of them experienced a return of symptoms. As a result, there are still dentists who advocate “weaning off” the appliances after phase one even though the disk will eventually redislocate, because they don't understand how to alter the bite in the manner needed to maintain the disk recapture. Although we do not recommend wean-off as a substitute for finishing, if your clicking returns without symptoms, you may want to consider the wean-off option.

PHASE TWO (FINISHING)

Once your jaw feels stable and comfortable in its new position, the second phase of treatment frees you from dependence on a daytime appliance.  This finishing step is necessary, because the disk acts like a shim under a table leg. Initially, the dislocation of the disk removed the shim and thereby slightly changed the angle of the lower jawbone so the teeth no longer fit together. Subsequently, the teeth shifted in order to recreate a stable bite with the disk dislocated.  Putting the disk back between the bones separates them slightly and thereby creates a small gap between the back teeth. The daytime appliance keeps the disk in place partly by filling that gap. Later the gap will need to be filled on a more permanent basis to keep the disk in place. The choice of what type of finishing is best for you depends largely on your dental condition. The various options are described below.

PASSIVE ERUPTION - is the simple and inexpensive way to restore the bite, but it is very slow.  In this process, the appliances are made progressively smaller by uncovering one or two teeth at a time until they erupt naturally into contact, which usually takes a couple of months, then another couple of teeth are uncovered.  Over time, the daytime appliance keeps getting smaller, and the new improved jaw position becomes more supported by natural teeth.  Eventually, the daytime appliance can be simply removed, and the last couple of teeth uncovered can erupt into contact.  This process is illustrated from top to bottom below.  In A, the mandible is located too far posteriorly as indicated by the arrow in the condyle.  In B, the disk has been recaptured by shifting the mandible and the condyle down and forward.  In C, a flat front bite plate is place between the front teeth.  In D, the molars are erupted.  In E, the premolars are erupted.  F is the new bite.

 eruption.jpeg

ACTIVE ERUPTION

This eruption process to restore your bite on your natural teeth can also be accelerated by temporarily fastening little buttons to the teeth to be erupted and connecting them by little orthodontic elastics that pull them together more rapidly.

BUILDING UP TEETH

For teeth with previous fillings, finishing is usually accomplished by building up the bite surfaces of either upper or lower back teeth to the same height and contour as the bite surface of the daytime appliance.  Afterwards, each individual back tooth looks and acts like a normal tooth, except that its top is a carefully designed orthopedic bite surface which supports your mandible in its ideal position.

The most inexpensive way to rebuild the bite surfaces of the natural teeth is with a tooth-colored plastic filling material called composite resin. It bonds with tremendous strength to enamel, and it provides some structural reinforcement for teeth that have been weakened by fillings, but it will chip or wear down over time, requiring maintenance by your general dentist.  

The best way to rebuild a bite that stabilizes the disk recapture is with crowns and onlays made of porcelain or gold.  Porcelain has excellent esthetics, but the lab process required makes it difficult to create an accurate bite surface. Gold is the ideal material for reconstructing bite surfaces, because it is extremely accurate, it is strong even when thin, and it has a hardness very similar to natural tooth structure – which minimizes wear. In addition, gold can be bonded to enamel with impressive strength.   For a combination of esthetics, function, and economy; gold onlays on the molars are frequently combined with composite resin onlays on the premolars which are smaller teeth and are exposed to smaller biting forces than molars.

COSTS

The initial cost of fabricating the day and night disk recapturing appliances is $2600.  The costs for finishing vary from hundreds for adjusting bites by selectively drilling down some teeth and/or passively erupting others to thousands for building up teeth.