Hi dear Dr. Essam.

I suggest to have a look at this. It might be helpful.

Dear Dr. Essam, 

I believe both are important and should be evaluated together.

We know physical impairments are not always related to pain or limited function

Nevertheless, you could consider using RDC, Helkimo Index(1) or more modern exams such as MRI (articular pathologies) or QSTs.

Good luck!

1) Sven Tandlak Tidskr. 1974 Mar;67(2):101-21.

Studies on function and dysfunction of the masticatory system. II. Index for anamnestic and clinical dysfunction and occlusal state.

Helkimo M.

Dear Dr. Essam,, 

I agree with dr. Furquim, that both aspects are important - subjective and objective as well. 

Expanding the taxonomy of the diagnostic criteria for temporomandibular disorders. Peck et al  2014

Dear  Dr Essam and other  responders,

Interesting theme:. In several studies  on the spine , hip shoulder and head(ache) , subjective assessment  is the driver which  test we choose. If we cluster this  tests  te  

diagnosis may  be accurate ( Schiffmann  2014). It is important that we choose clinical tests which have  a moderate till  excellent reliability  and  responsively. Send you a overview article of the tests 

Dear Dr Essam and contributors

I think both would work there was a paper published comparing a self administered questionnaire result (mainly subjective) patients words with clinical examination findings (mainly objective) in patients with TMD,  The inter and intra observer reliability was good  to excellent. 

Journal of Orofacial Pain . Winter 1998, Vol. 12 Issue 1, p42-51. 10p.

Thanks for the above answer and links, but, if I want to pool  the signs and symptoms of TMD in one analysis to estimate the risk ratio of the outcome variable. Should I use subjective or objective data?