Ethology involves investigation of certain behaviors under natural conditions to evaluate ways to improve function. Intraoral sleep appliances that prevent obstructive sleep apnea align the maxilla and mandible in such a way as to dilate and stent the oropharyngeal opening. Interarch stabilization guides specifically position the mouth parts for laboratory fabrication of the oral appliance. Two types of interarch stabilization guides are compared in this paper. Anterior stabilized interarch registration guides were considered the norm until recently. Based on ethological study, it was noted that anterior stabilization typically results in slant, or reduced posterior oropharyngeal opening. Based on the direction of functional contraction of the masticatory muscles, the anatomic phenomenon termed “elevator muscle crunch”, in combination with anterior stabilization typically reduces the oropharyngeal opening. Use of a posterior stabilization interarch registration guide, a recent innovation, that results in a parallel interarch arrangement, no slant and a larger, more patent oropharyngeal airway opening is discussed. Applying ethological investigation and known anatomic principles to the practice of airway focused dentistry

Keywords: Slant; Airway Focused Dentistry; Anatomic Principles