a bend in the cable 544 of greater than 90 degrees but less than 180 degrees the guiding fins 562 are in mechanical contact with the cable 544 and provide frictional resistance that compensates for any tensile strain applied to the cable for example due to longitudinal forces applied along the cable 544 in some embodiments the guiding fins 562 provide frictional resistance of at least 100 newtons in some embodiments the guiding fins provide frictional resistance greater than the weight of the mouthpiece in some embodiments the guiding fins provide frictional resistance greater than the forces required to disconnect the mouthpiece 140 from the controller 120 in some embodiments a rubber grommet 563 provides an elastic mechanical attachment between the outer shell 505 and the cable 544 with the outer shell 505 providing a resistance that counteracts any bending strain applied to the cable 544 e g the patient may accidentally pull or tug on the cable while the mouthpiece 500 is secured within the patient 39 s mouth in some embodiments the spacer 508 includes an elastomeric element that provides a mechanical connection between the cable 544 and the entrance fins 561 the elastomeric element provides a frictional force that provides a frictional resistance that counteracts any bending stress applied to the cable 544 in some embodiments the cable 544 can exit the outer shell at a 90 degree angle and be attached to the outer shell by an epoxy the epoxy providing mechanical resistance of up to 100 newtons to accommodate bending strains induced by the patient in some embodiments the cable 544 is attached to the outer shell by an adhesive or glue in some embodiments the cable 544.