こう合採得法の相違による水平的下がく位の変動

Abstract

The purpose of this study was to compare and evaluate the relative reproducibility and equality as well as jaw relationships produced by four jaw guiding methods; the gothic arch tracing, the voluntary tapping, the myomonitor centric and to occlude warm wax bite rim by light habitual closure. Four patients were selected whose remaining teeth had already lost the maximum intercuspation. The intraoral tracer was fixed on upper complete denture base and lower removable partial denture in three cases. Only in one dentulous case needed complete occlusal rehabilitation, the appliance was fixed on transfer coping crowns.The mandibular position guided by each methods was measured to the nearest 0.1mm in laterally and anteroposteriorly (x and y components). The accuracy of this experiment was estimated at 0.22mm (±2σ) or 0.34 mm (±3σ). This error was derive from width of tracing line, area of tapping point, mobility of denture base and mounting on articulator. Within the limits of this investigation, it is concluded that;1. Each guiding methods determined different mandibular position in case 1, 2 and 4. But in case 3, they terminated in the same mandibular position.2. The gothic arch tracing produced the least variable and the voluntary, tapping the most variable. The habitual closure tended toward eccentric position laterally. The myo-monitor centric produced more variable than the gothic arch tracing but less than the habitual closure.3. The estimated region of apex point was 0.57mm in laterally and 0.45mm in anteroposteriorly, the myo-monitor centric showed 0.62mm in laterally and 0.76mm in anteroposteriorly, the habitual closure determined 0.97 mm in laterally and 0.96mm in anteroposteriorly and the voluntary tapping produced 0.95mm in laterally and 1.59 mm in anteroposteriorly in an average of rejection ellipse (α=0.05).4. In an average of mandibular positon in anteroposteriorly, the gothic arch apex was the most retruded. The distance between apex point and the habitual closure was 0.4mm, the myo-centric was 0.7mm and the voluntary tapping was 0.9mm anterior.5. An average distance between apex point and mean points of each methods produced more consistent mandibular position that ranged within 0.15mm in laterally.