Hello again friends, after a long time.

After RND / maxillectomy (and later Radiotherapy) my mother (45) has had limited jaw motion. For exercising, she was initially given a small metallic contraption -- an angle (or hinge, if you like) whose open end you put between you teeth, and increase the opening gradually using a screw that goes through the angle. Roughly like a screw jack.
The problem with this device was that the pressure of opening is borne completely by the front-teeth alone.

So, at great expense we acquired a Therabite device (not easily available here in India). This spreads the pressure uniformly on the jaw, and the mechanism of its opening is more natural. But in a few months we've started facing problems with that too.

Firstly, the bitepads they came with got worn out very quickly as the teeth dig into them and tend to slide outward as the device is opened. We got a replacement set shipped from the US, again very expensively, and they too didn't last.*

[img:right]http://i50.tinypic.com/axyb06.jpg[/img] Secondly, the jaws of the device (the white part) are of flexible construction, so the actual opening the mouth gets is much smaller than what's indicated on scale. More so if the teeth slide outward along the angle. If I tightly my mother's head and the device as she exercises (to prevent teeth sliding), she seems to easily reach the maximum opening the device allows. In reality however, she can't put in more than two fingers into her mouth!

Her jaw range has actually reduced since she started using the therabite. We have checked all the settings on the device, and done what we could think of in improving her method of using it (suggestions are welcome). Now, she has switched back to that jack-like device which is visibly straining her incisors, as expected.

I suspect we might have ended up with a bad piece of equipment, but Support for the therabite is harder to find here than the device itself. So if you are someone who's used it before, please tell me:
- how quickly you had to replace the bitepads
- if the jaws on your device are prone to bending under pressure.

Thanks in advance!

I would like to add that am really grateful for the support this forum has given me in the past, and feel bad for not being more active here and contributing towards helping others.

--Ankur

*As an experiment, this time we had ordered the thick Edentulous version of the bite-pads, which was made of even less durable material.

I've been using a Therabite for over a year now. The pads do fall off but I just clean them and reattach them with white glue and clip them until they dry overnight.
It sounds like there is a bite issue as if your Mom presses her teeth right up against the little rim shown in your picture, her teeth shouldn't slide. It also sounds like you Mom is biting too hard onto the pads. The speech therapist who gave me mine emphasized that I should only lightly rest my teeth against the white rim and on the pads and not clamp down or bite at all. Instead let the Therbite open and stretch the jaws. In rereading my instruction booklet it does say: [quote]Your front teeth should just touch the inside rim of the upper Mouthpiece. Be careful to hold the jaw mobilizer level. Slowly squeeze the lever. DO NOT BITE ON THE MOUTHPIECES[/quote]
The upper jaw is just one solid piece of plastic so it should not be bending at all. The lower jaw does flex a little but not so you would notice.
Again, I would recheck the settings, especially the white knob at the handle that sets the distances. It turns in an odd way, the exact opposite of what I expected. Try resetting that. Plus check that the pin in the upper Range Setting Arm is at the last hole towards the mouthpieces (it appears that way in the picture you attached.
Sorry for all your problems and hope this helps
charm

I use the therabite. It came with an extra set of teeth pads, so when the first pads got bad, I replaced them. I wished I hadn't because the replacement pads have never stayed on and I have not had any luck on finding where to purchase new ones. So I would be interested in knowing where you can order these. I hadn't thought of the glue, I might try that.

I do not have any trouble with keeping it in place and working properly. I just don't feel like I have made any progress after the initial first month. I still can not get two fingers between my front teeth and my Prothodontist said that it might not get any better. When I was able to open it at the initial setting then I would turn the nob to increasse the opening and kept increasing until I got to the current setting, which is where I have been stuck.

Thanks Charm and Sharon,

I will see if I can get my mother to not bite. She finds the idea impossible--if the device presses against the teeth, the teeth must press back, says she.

As for the flexibility, what you say strengthens my suspicions of a bad device. The upper mouthpiece is a white plastic arc that attaches to the blue main body through a narrow neck. In my device, this is how bendy the white part is--with the body held in my left hand, a moderate effort using my right thumb and index finger at the tips of the white arc bends it inward by over one centimetre (2/5").
Is that the same with your device?
The lower mouthpiece is one big white thing, and is relatively rigid.

The settings are correct, according to what you say (I'm an engineer, one may expect at least that much).

@Sharon
I got new bitepads from CranioMandibular Rehab, Inc. There was some problem with billing the order but everything cleared up eventually. Being in the US, you should have no issues. The replacement ones have their own gum.
As for external glue, Fevi Kwik works ok for us. Coming-off isn't the problem, in my case the pads get cut-through and ruined completely.

Thanks again!

I had never even tried to bend the upper or lower jaw pieces of the Therabite but after reading your post, I did. Surprisingly, my upper one also flexed easily just as you described and just as much. I'm not an engineer but this suggests to me that the problem is not with the device. Since you have configured your therabite correctly, the only variable in the equation appears to be your mother's "biting". The force of a biting jaw is very powerful and my therapist did stress that I had to consciously refrain from biting down on the mouthpieces. The teeth just go along for the ride, they don't press back.
This must be very frustrating to you and I wish I could solve it, but Trismus is a big issue that keeps coming back (I've been struggling with it for almost three years). I know there are similar devices to the Therabite such as the Dynasplint but their web photos looked very very uncomfortable and weird to me.
Finally, it could also simply be that the damage to your mother's jaw muscles and nerves is simply too great to be remediated by any device. I sadly know this in the context of swallowing where every exercise or device (including the vaunted VitalStim electrical therapy) has not worked for me.
You are a very good son and caregiver
Charm

I am sitting here after looking at mine. I would say it basically appears rigid and I would be afraid to push the top plate down, so there is very little flexibility, if any. I just rest my mouth on it, very lightly and gently. Then as i squeeze the handle, very slowly forcing the mouth open with the up aand down motion. One thing they told me to do it slowly, and then hold it open for the count of seven. Most of the pressure seems to be on the back teeth(or prosthesis) and I feel the stretching in my jaw. I just open until I begin to feel pain, count to seven and then release it. Did you Mom have someone demonstrate it? Does she have an obturator? Is doing these exercises with the obturator in?

Excellent point Sharon. I need to take out my palate drop when I use the Therabite. Also I was told to try to open my mouth independently of the therabite while I was using it, and just have the therabite stretch it past what I could do. All the pressure is on my back teeth and jawbones also.

I wish there was an easy answer to Trismus but I'm told it's chronic and this will just be a daily exercise to keep my jaws from closing up.
Charm

Thanks again, Charm and Sharon.

From Charm's description of her device, and from the fact that you both feel the pressure on your back teeth, the problem does seem to have to do with the way of using it.

I'm getting the picture now, it's all connected. Pressure at the wrong place leads to bending of the mouthpieces where it should not happen. That in turn leads to insufficient opening, and also to the tendency of teeth to slide outwards and cut through the pads.

She does remove her obturator while exercising.

No one demonstrated the use to us. I have managed to contact ATOS support here, and will ask them to give us a demonstration. Or fix/replace the device in case something's wrong.

Thanks again for the replies, it was really helpful!

I have done it a few times with the obturator out (usually only because I forgot to do my exercises and already had taken it out for the night), but mostly use the therabite with it in. I think it gives an additional pressure point to help avoid too much on the front teeth.