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Unilateral posterior contact in excursive position
The patient presented complaining of a 13 year history of:
     Pain and pressure behind the eyes;  ringing in right ear;  headache at forehead and around skull.
     An NTI had been delivered at another facility.  Patient discontinued its use after one month due to ineffectiveness, but brought it with him as well as his complete collection of failed splints.

     The first consideration is to identify what parafunctional activity could result in such a presentation.

 --A chronic tension and strain on a pterygoid plate of the sphnoid bone elicits "sinus" pain and pressure (behind the eyes), which is created by a chronic pulling by a lateral pteryoid. (example)

--In order for a lateral pterygoid to generate considerable force, it must shorten to a degree (thereby translate its condyle) and then encounter resistance (occluded teeth, made possible by a chronically contracted temporalis, that is, clenching). (example)

--When one condyle is translated during jaw clenching, the contralateral side may be distalized, putting pressure on the posterior joint space, thereby eliciting tinnitus.
Since this act would have to occur in an excursive position, the clenching intensity is less efficient (that is, intense) than it would be in CO, therefore, the degree of chronic headache is mild to moderate.
 

Centric occlusion
  
With lower NTI device in CR

The DE had been properly narrowed...

...to avoid canine contact in excursive movement.

However, in an extreme right excursive movment...
...a posterior contact existed.
Without  the device in place (pictured to the left), the patient's parafunctional ability allowed for the left posterior contact as well.  Not surprisingly, the two occluding teeth  had received root canal therapy in the attempt to address their chronic "achyness" and temperature sensitivity.  This parafucntional occluding obligates and allows the left lateral pterygoid to maintain considerable contraction intensity in a static state, thereby pulling on its origin, the pterygoid plate of the sphenoid bone, resulting in "sinus" pain and pressure (behind the eyes).  Meanwhile, the right condyle's posterior space is strained, resulting in tinnitus.  The chronic clenching results in chronic headache.

The opposing interfering cusps were reduced.
The patient reported that he no longer felt that the left posterior "hit first" upon closure.
The patient was instructed to resume nightly wear of the NTI.  Within the first four days following the reduction of the interference, symptoms had reached an 80% resolution.