Variations in rest vertical dimension: effects of headrest in edentulous patients

Some clinicians believe that using a headrest may result in an inaccurate rest vertical dimension (RVD) and thus alter the occlusal vertical dimension when fabricating complete dentures. This study measured the RVD established by a group of totally edentulous subjects seated in a relaxed upright position with the Frankfort Plane parallel to the horizontal and the head unsupported and compared this measurement with the RVD established when the same subjects were seated in a relaxed upright position and looking straight at the horizon with the head supported by a headrest. The mean values obtained when the head was unsupported were compared to those obtained when the head was supported by a headrest. Statistical analysis was performed using Student's t-test (alpha = 0.05). No significant differences were noted in the RVD between the two positions (P = 0.38).