Never wear an NTItss appliance while eating.  The NTItss is not a functional appliance.  (Doing so may be painful and possibly traumatic to the opposing teeth).

Avoid sleeping on your stomach.  Sleeping on your stomach forces your head to be turned  to the side, which may allow significant muscular strain.

 Discontinue all gum chewing.

NTItss use should be discontinued and adjusted by your doctor
-if it is uncomfortable, too tight or binding, too loose (can be removed with your tongue), or damaged.

-if when wearing the NTItss, your back teeth or canine teeth can somehow touch each other in various jaw positions.

Understand that
The NTItss suppresses muscle dysfunctions and is not an orthodontic appliances which can move teeth. Daily chewing (without wearing the NTItss) will maintain each tooth's original position.  Those familiar with any type of removable custom mouthpiece realize that a mouthpiece may fit poorly if it has not been worn for an extended period.  This is due to the constant, casual adaptation of the teeth to the varying (para)functional forces being applied to them.

 The jaw is like a garage door (spring hinge type).  Just as the tension of the garage door springs influence the path of closure of the door and its final fit, so does the tension of the jaw musculature influence the path of closure and final fit of the teeth.  If one garage door spring is significantly tighter than the other (even though the door may be fitting adequately upon closure), decreasing the tension of that spring will effect the final fit of the door, and may necessitate the modification of the door to ensure efficient closure. Similarly, reducing jaw muscle tension may allow the jaw joints to achieve their most natural, relaxed orientation and allow the jaw to close in its best and most natural path of closure, which may be different than what the patient originally presents with. This only occurs in the presence of relief of symptoms.  In this event, your dentist may recommend modifying the occlusal scheme of your teeth to achieve the most efficient closure (or "bite").

 Pre-existing jaw joint noises are not necessarily indicative of pathology or disease, but may be permanent adaptive conditions to historical muscle dysfunction or trauma.  The NTItss may allow the degree of "loudness" to decrease or resolve completely.  Your dentist will recommend diagnostic tests for specific jaw joint disorders.

Part of the historical "Standard of Care" in dentistry for jaw related conditions had been to provide a "full coverage" mouthpiece.  These appliances cover all of the upper or lower teeth and are intended to deflect or modify the forces generated by muscle parafunction.  Unfortunately, these appliances can also allow for the intensity of muscle parafunction to increase, by simply providing a more efficient surface to bite on.  The NTItss appliance is specifically designed to suppress muscle parafunction intensity, not modify or enhance it.

Complete resolution of your symptoms may not occur immediately.  Muscular parafunction can be aggressive in its attempt to maintain itself.  Typically, the jaw's range of motion improves, allowing it to achieve orientations that allow for continued, or new, symptomatic presentation. Your dentist may need to adjust or modify the NTItss as the condition adapts and attempts to "defeat" the NTItss.