The national institute of health I linked to above advises against contested, invasive treatments. I have no vested interest in any treatments, nor products. I am just a person with wrecked TMJoints (multiple severe dislocations from sports and car accidents, and chronic bruxism). I wouldn't be surprised to learn that you are a doctor or dentist who is invested in treatments for TMJoint related pain. In any case, I am not, nor am I a salesman, not am I vested in any way, other than experience and results.
I spent a mansion-worth of dollars, trying every invasive, bite changing, therapeutic treatment for TMJ related pain, that various dentists, TMJ specialist dentists, doctors and pain specialists could think up. This included arthroscopic surgeries (Mayo is at least honest enough to state that titanium replacment often gives NO pain relief), Botox (causes long term jaw bone density reduction), progressive splints, NTI devices, many drugs, physical etc. therapies, etc. etc. A very few of them temporarily interrupted my TMD bruxism, and temporarily reduced my levels of pain. Most made it worse or did nothing but spend my life savings. The worst was getting temporary results, and temporary hope.
I knew I was a bruxer, and found that the slimmest, slightly flexible bite guard, made by my dentist who also bruxes, really reduced harm to my teeth and my dental work. It also did not increase leverage on my ruined TMJoints, nor TMJoint area pain, like some of the fancy splints did.
Then I learned that venerable, proven, non-invasive EMG sleep studies are the most effective diagnostic for TMD bruxism. And EMG sleep studies will also track your reduction in bruxism. And it meant I could finally manage my pain levels and have a life again.
There is nothing contested about diagnosing TMD bruxism with EMG. In fact, the original sleep centers that tested for apnea, like Stanford's, used to include an electrode to the temporal muscle. One thing they were trying to do was see if there is a significant relationship between chronic TMD sleep bruxism and apnea, which I don't think anyone ever proved.
I just wish I had all the money I spent on expensive, invasive TMJD treatments that ASSUME a diagnosis, based upon structural analyses.
If bruxism is not causing your TMJoint related pain, EMG won't help you at all, except to rule out chronic sleep bruxism as a cause of your TMJoint related problems. Ruling out a diagnosis is a time tested way to save a lot of time, pain, side effects, and money. You can rent from a dentist now (there's a list of dentists in various states).
There are unfortunately still many pain conditions, that you STILL have to diagnose by trying on treatments, then diagnosing by results, like hereditary migraine, for example. But TMD bruxism is no longer on this list. And TMD bruxism can cause a lot of TMJoint related problems.
I expect that sleep studies for TMD bruxism will become eventually covered, like sleep studies for apnea. In any case, it's non-invasive and tracks what's going on, instead of making assumptions. And a lot cheaper and safer than invasive treatments.
You are correct that exactly how CES biofeedback works on TMD bruxism is not yet fully documented with enough double blind studies for the kind of agreement that EMG has. But Electromylography is completely understood as effective, both diagnostically, and also for effectively monitoring reduction in chronic sleep bruxism.
So it would be tragic if anyone conflates questions about biofeedback or CES with EMG. And non-invasive CES does not interrupt normal restorative sleep patterns.
I just see no benefit to patients in sowing doubt about the NIH reccomendations, or in EMG as a diagnostic or monitoring tool.