ABSTRACT
Ignoring the functional activity of boundary muscles in complete denture construction leads to loss of denture retention, stability and causes other problems and eventually leads to patient dissatisfaction. Recording the neutral zone and utilization it will prevent these problems. Neutral zone has been defined as a space of edentulous area in patient's mouth where the force of the tongue pressing outward is neutralized by forces of the cheeks and lips pressing inward. Recording and utilization of Neutral zone is more important information denture polished surface contours and teeth orientation specially in patients with vigorously atrophic ridges, elderly patients and patients with decreased occlusal vertical dimension. In this study introducing the technique, neutral zone was recorded in a patient lack of muscle tonicity was recorded in maxillary and mandibular acrylic rims which had been made in both jaws special trays. After two weeks and two month follow-ups, the patient was satisfied with her prosthesis; so this technique seems to be an appropriate method for complete denture construction, especially in patients with lack of muscle tonicity