Paul,

The light cured composite resin is indeed the stuff  your dentist cures 
with a blue laser -- but you don't need a laser to cure it.  Actually 
room light will cure the resin but it takes a long time.  Curing time is 
directly proportional to intensity of the source.  The light source most 
commonly used is a quartz bulb.  In the dental office, because the light 
is so tightly focused, using protective shield is recommended. 

Of course, they make units specifically for curing resin -- they start 
about $200 but any intense full spectrum light will work.  Different 
initiators -- the chemical compounds added to facilitate the cure of the 
resin -- are sensitive to different bands of the spectrum.  Most seem to 
prefer the "high frequency" end hence the "blue laser"

Although the material would be very good for the purpose of restoring 
mouthpieces, I was really just joking about it because the cost would be 
prohibitive.  The material is expensive, the curing light is expensive 
and the finishing and polishing material is expensive.  But if you 
happened to already have the stuff...

Dan,

If your repair seems solid, I'd leave it alone.  Dentist and labs use a 
technique known as "microetching" to provide mechanical retention for 
resins.  This amounts to either a mini sand blaster or acid bath.  Both 
provide an extremely fine "patina-like" finish but it is enough for the 
resin to "grab".  My point is, the stuff can get ahold of very little 
and be fine.  Having typed that, more retention is usually better.  The 
contact cement provides an "adhesion", but it is not a true bond.  
Adhesion and chemical bond are physically different joints.  Adhesion 
generally works best when you have a gloss finished surface like 
polished stainless steel.  None the less, adhesion  generally has less 
strength than chemical bonding.

In regards to chips and tip damage, that is where the resin material 
works best, in my opinion.  The orthodontic acrylic that most of you 
seem to be using is very strong even when thin.  However, this is an 
area where some mechanical retention is a good idea.  I suggest 
preparing some fine grooves or undercuts in the base of the defect for 
the repair material to "lock" into.  The folks at Schein dental can hook 
you up with some dental laboratory burs that will work in a Dremel or 
similar tool.  A 1/2 round or #33 inverted cone shape are ideal for 
this.  Again the light cured resin is better when thin but then, the 
start up cost would be prohibitive for most folks.  On the other hand, 
if you have a good friend who is a dentist, maybe...

Dr. T
================
MouthpieceWork@yahoogroups.com wrote:

>________________________________________________________________________
>
>Message: 1         
>   Date: Tue, 16 Nov 2004 19:22:19 -0600
>   From: Jeff & Joan Turner <capjeff@...>
>Subject: Re: Acrylic biteplate
>
>I've been following this discussion in regards to using dental acrylic for repairs and reconstruction of mouthpieces...
>________________________________________________________________________
>________________________________________________________________________
>
>Message: 2         
>   Date: Tue, 16 Nov 2004 21:18:19 -0600
>   From: Paul Coats <tenorman@...>
>Subject: Re: Re: Acrylic biteplate
>
>Dr. Turner... is this "light cured composite resin" the stuff my dentist 
>cures with a blue laser?
>
>(Really, guys, he puts on tinted goggles to do this.)
>
>Paul Coats
>==========================
>
>Message: 3         
>   Date: Wed, 17 Nov 2004 15:12:18 -0600
>   From: Dan Torosian <dtorosian@...>
>Subject: Re: Re: Acrylic biteplate
>
>Jeff & Joan Turner wrote:
>  
>
>>Using acrylic with non acrylic materials requires mechanical retention because there is no true "bond" between the materials.
>>    
>>
>Thanks for the info. 
>
>Do you think I should try to pry the new biteplate off of the stainless 
>steel and contact-cement it in instead, or just leave it alone if it 
>seems solid?
>
>Have you used acrylic to repair chips and other damage around the edges 
>of the mouthpiece? Is it sturdy enough when it gets thin (like at the 
>tip)?   I have only used it to fill in tooth gouges or to make a biteplate.
>
>Dan
>  
>