Hello and welcome .. My name is XXXXX XXXXX I am an experienced small animal veterinary surgeon, I will be very pleased to work with you today and will try my best to answer your question to your satisfaction.
Please can you answer : Is you dog otherwise quite happy and behaving normally and is eating well?
This is a fairly simple problem which you see now and again, if it only happens when he yawns he most likely has some arthritis or inflammation in the joints in his jaw.
To be honest there is little you can do for this other than the metacam, if it was stress or discomfort anywhere else in his body the symptoms would not occur only when he yawns ..
I have never had much success in treating this but you should have your vet check this over the next time you take him in just in case ...
Hello again,Yes I would try the full dose for a couple of weeks and see what happens, that could well make a big difference ...I have always found metacam to be very safe and have had very few problems with it. If you have a screening blood test run say every six months you should get early warning if this class of drug is having side effects or making his existing problems worse ....Regards,Scott